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proc(4) 				   File Formats 				  proc(4)

NAME
       proc - /proc, the process file system

DESCRIPTION
       /proc  is a file system that provides access to the state of each process and light-weight
       process (lwp) in the system. The name of each entry in the /proc directory  is  a  decimal
       number  corresponding to a process-ID. These entries are themselves subdirectories. Access
       to process state is provided by additional files contained within each  subdirectory;  the
       hierarchy is described more completely below. In this document, ``/proc file'' refers to a
       non-directory file within the hierarchy rooted at /proc. The owner of each /proc file  and
       subdirectory is determined by the user-ID of the process.

       /proc  can  be  mounted on any mount point, in addition to the standard /proc mount point,
       and can be mounted several places at once. Such additional mounts are allowed in order  to
       facilitate  the confinement of processes to subtrees of the file system via chroot(1M) and
       yet allow such processes access to commands like ps(1).

       Standard system calls are used to access /proc  files:  open(2),  close(2),  read(2),  and
       write(2)  (including  readv(2),	writev(2),  pread(2), and pwrite(2)). Most files describe
       process state and can only be opened for reading. ctl and lwpctl  (control)  files  permit
       manipulation of process state and can only be opened for writing. as (address space) files
       contain the image of the running process and can be opened for both reading  and  writing.
       An  open  for  writing  allows process control; a read-only open allows inspection but not
       control. In this document, we refer to the process as open for reading or writing  if  any
       of its associated /proc files is open for reading or writing.

       In general, more than one process can open the same /proc file at the same time. Exclusive
       open is an advisory mechanism provided to allow controlling processes to avoid  collisions
       with  each other. A process can obtain exclusive control of a target process, with respect
       to other cooperating processes, if it successfully opens any  /proc  file  in  the  target
       process	for writing (the as or ctl files, or the lwpctl file of any lwp) while specifying
       O_EXCL in the open(2). Such an open will fail if the target process is  already	open  for
       writing (that is, if an as, ctl, or lwpctl file is already open for writing). There can be
       any number of concurrent read-only opens; O_EXCL is ignored on opens for  reading.  It  is
       recommended  that the first open for writing by a controlling process use the O_EXCL flag;
       multiple controlling processes usually result in chaos.

       If a process opens one of its own /proc files for writing, the open succeeds regardless of
       O_EXCL  and  regardless	of  whether  some other process has the process open for writing.
       Self-opens do not count when another process attempts an exclusive open. (A process cannot
       exclude	a debugger by opening itself for writing and the application of a debugger cannot
       prevent a process from opening itself.) All self-opens for writing are forced to be close-
       on-exec (see the F_SETFD operation of fcntl(2)).

       Data  may  be  transferred  from  or  to  any locations in the address space of the traced
       process by applying lseek(2) to position the as file at the virtual  address  of  interest
       followed by read(2) or write(2) (or by using pread(2) or pwrite(2) for the combined opera-
       tion). The address-map files /proc/pid/map and /proc/pid/xmap can be read to determine the
       accessible  areas  (mappings) of the address space. I/O transfers may span contiguous map-
       pings. An I/O request extending into an unmapped area is  truncated  at	the  boundary.	A
       write  request  beginning  at  an  unmapped virtual address fails with EIO; a read request
       beginning at an unmapped virtual address returns zero (an end-of-file indication).

       Information and control operations are provided through additional files. <procfs.h>  con-
       tains  definitions  of  data structures and message formats used with these files. Some of
       these definitions involve the use of sets of flags. The set types sigset_t, fltset_t,  and
       sysset_t  correspond, respectively, to signal, fault, and system call enumerations defined
       in <sys/signal.h>, <sys/fault.h>, and <sys/syscall.h>. Each set type is	large  enough  to
       hold flags for its own enumeration. Although they are of different sizes, they have a com-
       mon structure and can be manipulated by these macros:

	 prfillset(&set);	      /* turn on all flags in set */
	 premptyset(&set);	      /* turn off all flags in set */
	 praddset(&set, flag);	      /* turn on the specified flag */
	 prdelset(&set, flag);	      /* turn off the specified flag */
	 r = prismember(&set, flag);  /* != 0 iff flag is turned on */

       One of prfillset() or premptyset() must be used to initialize set before it is used in any
       other operation. flag must be a member of the enumeration corresponding to set.

       Every  process  contains  at least one light-weight process, or lwp. Each lwp represents a
       flow of execution that is independently scheduled by the operating system. All lwps  in	a
       process	share  its  address  space  as	well as many other attributes. Through the use of
       lwpctl and ctl files as described below, it is possible to affect  individual  lwps  in	a
       process or to affect all of them at once, depending on the operation.

       When  the  process has more than one lwp, a representative lwp is chosen by the system for
       certain process status files and control operations. The representative lwp is  a  stopped
       lwp only if all of the process's lwps are stopped; is stopped on an event of interest only
       if all of the lwps are so stopped (excluding PR_SUSPENDED lwps); is in a PR_REQUESTED stop
       only if there are no other events of interest to be found; or, failing everything else, is
       in a PR_SUSPENDED stop (implying that the process is deadlocked). See the  description  of
       the  status  file  for definitions of stopped states. See the PCSTOP control operation for
       the definition of ``event of interest''.

       The representative lwp remains fixed (it will be chosen again on the  next  operation)  as
       long  as  all  of the lwps are stopped on events of interest or are in a PR_SUSPENDED stop
       and the PCRUN control operation is not applied to any of them.

       When applied to the process control file, every /proc control operation that must  act  on
       an  lwp uses the same algorithm to choose which lwp to act upon. Together with synchronous
       stopping (see PCSET), this enables a debugger to control a multiple-lwp process using only
       the process-level status and control files if it so chooses. More fine-grained control can
       be achieved using the lwp-specific files.

       The system supports two process data models, the traditional 32-bit data  model	in  which
       ints,  longs  and  pointers are all 32 bits wide (the ILP32 data model), and on some plat-
       forms the 64-bit data model in which longs and pointers, but not  ints,	are  64  bits  in
       width  (the  LP64  data	model).  In  the  LP64 data model some system data types, notably
       size_t, off_t, time_t and dev_t, grow from 32 bits to 64 bits as well.

       The /proc interfaces described here are available to both 32-bit  and  64-bit  controlling
       processes.  However, many operations attempted by a 32-bit controlling process on a 64-bit
       target process will fail with EOVERFLOW because	the  address  space  range  of	a  32-bit
       process	cannot	encompass a 64-bit process or because the data in some 64-bit system data
       type cannot be compressed to fit into the corresponding 32-bit type without loss of infor-
       mation.	Operations that fail in this circumstance include reading and writing the address
       space, reading the address-map files, and setting the target process's registers. There is
       no  restriction	on  operations applied by a 64-bit process to either a 32-bit or a 64-bit
       target processes.

       The format of the contents of any /proc file depends on the data  model	of  the  observer
       (the  controlling process), not on the data model of the target process. A 64-bit debugger
       does not have to translate the information it reads from a /proc file for a 32-bit process
       from 32-bit format to 64-bit format. However, it usually has to be aware of the data model
       of the target process. The pr_dmodel field  of  the  status  files  indicates  the  target
       process's data model.

       To  help  deal  with  system data structures that are read from 32-bit processes, a 64-bit
       controlling program can be compiled with the  C	preprocessor  symbol  _SYSCALL32  defined
       before  system  header  files  are  included.  This makes explicit 32-bit fixed-width data
       structures (like cstruct stat32) visible to the 64-bit program. See types32.h(3HEAD).

DIRECTORY STRUCTURE
       At the top level, the directory /proc contains entries each of  which  names  an  existing
       process	in  the  system. These entries are themselves directories. Except where otherwise
       noted, the files described below can be opened for reading only. In addition, if a process
       becomes	a  zombie  (one that has exited but whose parent has not yet performed a wait(3C)
       upon it), most of its associated /proc files  disappear	from  the  hierarchy;  subsequent
       attempts  to  open  them, or to read or write files opened before the process exited, will
       elicit the error ENOENT.

       Although process state and consequently the  contents  of  /proc  files	can  change  from
       instant to instant, a single read(2) of a /proc file is guaranteed to return a sane repre-
       sentation of state; that is, the read will be atomic with respect  to  the  state  of  the
       process.  No such guarantee applies to successive reads applied to a /proc file for a run-
       ning process. In addition, atomicity is not guaranteed for I/O applied to the as (address-
       space)  file  for  a  running process or for a process whose address space contains memory
       shared by another running process.

       A number of structure definitions are used to describe the  files.  These  structures  may
       grow by the addition of elements at the end in future releases of the system and it is not
       legitimate for a program to assume that they will not.

STRUCTURE OF /proc/pid
       A given directory /proc/pid contains the following entries. A process can use the  invisi-
       ble  alias  /proc/self  if  it wishes to open one of its own /proc files (invisible in the
       sense that the name ``self'' does not appear in a directory listing of /proc obtained from
       ls(1), getdents(2), or readdir(3C)).

   contracts
       A  directory  containing  references to the contracts held by the process. Each entry is a
       symlink to the contract's directory under /system/contract. See contract(4).

   as
       Contains the address-space image of the process; it can be opened  for  both  reading  and
       writing. lseek(2) is used to position the file at the virtual address of interest and then
       the address space can be examined or changed through read(2)  or  write(2)  (or	by  using
       pread(2) or pwrite(2) for the combined operation).

   ctl
       A  write-only file to which structured messages are written directing the system to change
       some aspect of the process's state or control its behavior in some way. The seek offset is
       not  relevant when writing to this file. Individual lwps also have associated lwpctl files
       in the lwp subdirectories. A control message may be written either to  the  process's  ctl
       file or to a specific lwpctl file with operation-specific effects. The effect of a control
       message is immediately reflected in the state of the process visible  through  appropriate
       status and information files. The types of control messages are described in detail later.
       See CONTROL MESSAGES.

   status
       Contains state information about the process and the representative lwp. The file contains
       a  pstatus structure which contains an embedded lwpstatus structure for the representative
       lwp, as follows:

	 typedef struct pstatus {
	      int pr_flags;	       /* flags (see below) */
	      int pr_nlwp;	       /* number of active lwps in the process */
	      int pr_nzomb;	       /* number of zombie lwps in the process */
	      pid_tpr_pid;	       /* process id */
	      pid_tpr_ppid;	       /* parent process id */
	      pid_tpr_pgid;	       /* process group id */
	      pid_tpr_sid;	       /* session id */
	      id_t pr_aslwpid;	       /* obsolete */
	      id_t pr_agentid;	       /* lwp-id of the agent lwp, if any */
	      sigset_t pr_sigpend;     /* set of process pending signals */
	      uintptr_t pr_brkbase;    /* virtual address of the process heap */
	      size_t pr_brksize;       /* size of the process heap, in bytes */
	      uintptr_t pr_stkbase;    /* virtual address of the process stack */
	      size_tpr_stksize;        /* size of the process stack, in bytes */
	      timestruc_t pr_utime;    /* process user cpu time */
	      timestruc_t pr_stime;    /* process system cpu time */
	      timestruc_t pr_cutime;   /* sum of children's user times */
	      timestruc_t pr_cstime;   /* sum of children's system times */
	      sigset_t pr_sigtrace;    /* set of traced signals */
	      fltset_t pr_flttrace;    /* set of traced faults */
	      sysset_t pr_sysentry;    /* set of system calls traced on entry */
	      sysset_t pr_sysexit;     /* set of system calls traced on exit */
	      char pr_dmodel;	       /* data model of the process */
	      taskid_t pr_taskid;      /* task id */
	      projid_t pr_projid;      /* project id */
	      zoneid_t pr_zoneid;      /* zone id */
	      lwpstatus_t pr_lwp;      /* status of the representative lwp */
	 } pstatus_t;

       pr_flags is a bit-mask holding the following process flags. For convenience, it also  con-
       tains the lwp flags for the representative lwp, described later.

       PR_ISSYS     process is a system process (see PCSTOP).

       PR_VFORKP    process is the parent of a vforked child (see PCWATCH).

       PR_FORK	    process has its inherit-on-fork mode set (see PCSET).

       PR_RLC	    process has its run-on-last-close mode set (see PCSET).

       PR_KLC	    process has its kill-on-last-close mode set (see PCSET).

       PR_ASYNC     process has its asynchronous-stop mode set (see PCSET).

       PR_MSACCT    Set  by  default  in  all processes to indicate that microstate accounting is
		    enabled. However, this flag has been deprecated and no longer has any effect.
		    Microstate	accounting  may not be disabled; however, it is still possible to
		    toggle the flag.

       PR_MSFORK    Set by default in all processes to indicate that microstate  accounting  will
		    be	enabled  for  processes  that this parent forks(). However, this flag has
		    been deprecated and no longer has any effect. It is possible to  toggle  this
		    flag; however, it is not possible to disable microstate accounting.

       PR_BPTADJ    process has its breakpoint adjustment mode set (see PCSET).

       PR_PTRACE    process has its ptrace-compatibility mode set (see PCSET).

       pr_nlwp is the total number of active lwps in the process. pr_nzomb is the total number of
       zombie lwps in the process. A zombie lwp is a non-detached lwp that has terminated but has
       not been reaped with thr_join(3C) or pthread_join(3C).

       pr_pid,	pr_ppid,  pr_pgid,  and  pr_sid  are, respectively, the process ID, the ID of the
       process's parent, the process's process group ID, and the process's session ID.

       pr_aslwpid is obsolete and is always zero.

       pr_agentid is the lwp-ID for the /proc agent lwp (see the PCAGENT control  operation).  It
       is zero if there is no agent lwp in the process.

       pr_sigpend identifies asynchronous signals pending for the process.

       pr_brkbase is the virtual address of the process heap and pr_brksize is its size in bytes.
       The address formed by the sum of these values is the process break (see	brk(2)).  pr_stk-
       base  and  pr_stksize  are, respectively, the virtual address of the process stack and its
       size in bytes. (Each lwp runs on a separate stack; the  distinguishing  characteristic  of
       the process stack is that the operating system will grow it when necessary.)

       pr_utime,  pr_stime,  pr_cutime,  and pr_cstime are, respectively, the user CPU and system
       CPU time consumed by the process, and the cumulative user CPU and system CPU time consumed
       by the process's children, in seconds and nanoseconds.

       pr_sigtrace and pr_flttrace contain, respectively, the set of signals and the set of hard-
       ware faults that are being traced (see PCSTRACE and PCSFAULT).

       pr_sysentry and pr_sysexit contain, respectively, the sets of system calls being traced on
       entry and exit (see PCSENTRY and PCSEXIT).

       pr_dmodel indicates the data model of the process. Possible values are:

       PR_MODEL_ILP32	  process data model is ILP32.

       PR_MODEL_LP64	  process data model is LP64.

       PR_MODEL_NATIVE	  process data model is native.

       The  pr_taskid,	pr_projid,  and pr_zoneid fields contain respectively, the numeric IDs of
       the task, project, and zone in which the process was running.

       The constant PR_MODEL_NATIVE reflects the data model of the controlling process, that  is,
       its  value is PR_MODEL_ILP32 or PR_MODEL_LP64 according to whether the controlling process
       has been compiled as a 32-bit program or a 64-bit program, respectively.

       pr_lwp contains the status information for the representative lwp:

	 typedef struct lwpstatus {
	   int pr_flags;	      /* flags (see below) */
	   id_t pr_lwpid;	      /* specific lwp identifier */
	   short pr_why;	      /* reason for lwp stop, if stopped */
	   short pr_what;	      /* more detailed reason */
	   short pr_cursig;	      /* current signal, if any */
	   siginfo_t pr_info;	      /* info associated with signal or fault */
	   sigset_t pr_lwppend;       /* set of signals pending to the lwp */
	   sigset_t pr_lwphold;       /* set of signals blocked by the lwp */
	   struct sigaction pr_action;/* signal action for current signal */
	   stack_t pr_altstack;       /* alternate signal stack info */
	   uintptr_t pr_oldcontext;   /* address of previous ucontext */
	   short pr_syscall;	      /* system call number (if in syscall) */
	   short pr_nsysarg;	      /* number of arguments to this syscall */
	   int pr_errno;	      /* errno for failed syscall */
	   long pr_sysarg[PRSYSARGS]; /* arguments to this syscall */
	   long pr_rval1;	      /* primary syscall return value */
	   long pr_rval2;	      /* second syscall return value, if any */
	   char pr_clname[PRCLSZ];    /* scheduling class name */
	   timestruc_t pr_tstamp;     /* real-time time stamp of stop */
	   timestruc_t pr_utime;      /* lwp user cpu time */
	   timestruc_t pr_stime;      /* lwp system cpu time */
	   uintptr_t pr_ustack;       /* stack boundary data (stack_t) address */
	   ulong_t pr_instr;	      /* current instruction */
	   prgregset_t pr_reg;	      /* general registers */
	   prfpregset_t pr_fpreg;     /* floating-point registers */
	 } lwpstatus_t;

       pr_flags is a bit-mask holding the following lwp flags. For convenience, it also  contains
       the process flags, described previously.

       PR_STOPPED    The lwp is stopped.

       PR_ISTOP      The lwp is stopped on an event of interest (see PCSTOP).

       PR_DSTOP      The lwp has a stop directive in effect (see PCSTOP).

       PR_STEP	     The lwp has a single-step directive in effect (see PCRUN).

       PR_ASLEEP     The lwp is in an interruptible sleep within a system call.

       PR_PCINVAL    The lwp's current instruction (pr_instr) is undefined.

       PR_DETACH     This is a detached lwp (see pthread_create(3C) and pthread_join(3C)).

       PR_DAEMON     This is a daemon lwp (see pthread_create(3C)).

       PR_ASLWP      This flag is obsolete and is never set.

       PR_AGENT      This is the /proc agent lwp for the process.

       pr_lwpid names the specific lwp.

       pr_why and pr_what together describe, for a stopped lwp, the reason for the stop. Possible
       values of pr_why and the associated pr_what are:

       PR_REQUESTED	indicates that the stop occurred in response to a  stop  directive,  nor-
			mally  because	PCSTOP	was  applied or because another lwp stopped on an
			event of interest and the asynchronous-stop flag (see PCSET) was not  set
			for the process. pr_what is unused in this case.

       PR_SIGNALLED	indicates  that  the  lwp  stopped on receipt of a signal (see PCSTRACE);
			pr_what holds the signal number that caused the stop (for a newly-stopped
			lwp, the same value is in pr_cursig).

       PR_FAULTED	indicates  that  the  lwp stopped on incurring a hardware fault (see PCS-
			FAULT); pr_what holds the fault number that caused the stop.

       PR_SYSENTRY	indicate a stop on entry to or exit from a system call (see PCSENTRY  and
       PR_SYSEXIT	PCSEXIT); pr_what holds the system call number.

       PR_JOBCONTROL	indicates that the lwp stopped due to the default action of a job control
			stop signal (see sigaction(2)); pr_what holds the stopping signal number.

       PR_SUSPENDED	indicates that the lwp stopped due to internal	synchronization  of  lwps
			within the process. pr_what is unused in this case.

       pr_cursig  names  the current signal, that is, the next signal to be delivered to the lwp,
       if any. pr_info, when the lwp is in a PR_SIGNALLED or PR_FAULTED stop, contains additional
       information pertinent to the particular signal or fault (see <sys/siginfo.h>).

       pr_lwppend  identifies any synchronous or directed signals pending for the lwp. pr_lwphold
       identifies those signals whose delivery is being blocked by the lwp (the signal mask).

       pr_action contains the signal action information pertaining to  the  current  signal  (see
       sigaction(2));  it  is  undefined if pr_cursig is zero. pr_altstack contains the alternate
       signal stack information for the lwp (see sigaltstack(2)).

       pr_oldcontext, if not zero, contains the address on the lwp stack of a ucontext	structure
       describing the previous user-level context (see ucontext.h(3HEAD)). It is non-zero only if
       the lwp is executing in the context of a signal handler.

       pr_syscall is the number of the system call, if any, being executed by the lwp; it is non-
       zero if and only if the lwp is stopped on PR_SYSENTRY or PR_SYSEXIT, or is asleep within a
       system call ( PR_ASLEEP is set). If pr_syscall is non-zero, pr_nsysarg is  the  number  of
       arguments to the system call and pr_sysarg contains the actual arguments.

       pr_rval1,  pr_rval2,  and pr_errno are defined only if the lwp is stopped on PR_SYSEXIT or
       if the PR_VFORKP flag is set. If pr_errno is  zero,  pr_rval1  and  pr_rval2  contain  the
       return  values from the system call. Otherwise, pr_errno contains the error number for the
       failing system call (see <sys/errno.h>).

       pr_clname contains the name of the lwp's scheduling class.

       pr_tstamp, if the lwp is stopped, contains a time stamp marking when the lwp  stopped,  in
       real time seconds and nanoseconds since an arbitrary time in the past.

       pr_utime is the amount of user level CPU time used by this LWP.

       pr_stime is the amount of system level CPU time used by this LWP.

       pr_ustack  is  the  virtual  address of the stack_t that contains the stack boundaries for
       this LWP. See getustack(2) and _stack_grow(3C).

       pr_instr contains the machine instruction to which the lwp's program counter  refers.  The
       amount  of  data retrieved from the process is machine-dependent. On SPARC based machines,
       it is a 32-bit word. On x86-based machines, it is a single byte. In general, the  size  is
       that  of  the machine's smallest instruction. If PR_PCINVAL is set, pr_instr is undefined;
       this occurs whenever the lwp is not stopped or when  the  program  counter  refers  to  an
       invalid virtual address.

       pr_reg is an array holding the contents of a stopped lwp's general registers.

       SPARC		    On SPARC-based machines, the predefined constants R_G0 ... R_G7, R_O0
			    ... R_O7, R_L0 ... R_L7, R_I0 ... R_I7, R_PC, R_nPC, and R_Y  can  be
			    used  as  indices  to  refer to the corresponding registers; previous
			    register windows can be read from their  overflow  locations  on  the
			    stack (however, see the gwindows file in the /proc/pid/lwp/lwpid sub-
			    directory).

       SPARC V8 (32-bit)    For SPARC V8 (32-bit) controlling processes, the predefined constants
			    R_PSR, R_WIM, and R_TBR can be used as indices to refer to the corre-
			    sponding special registers. For SPARC V9  (64-bit)	controlling  pro-
			    cesses, the predefined constants R_CCR, R_ASI, and R_FPRS can be used
			    as indices to refer to the corresponding special registers.

       x86 (32-bit)	    For 32-bit x86 processes, the predefined constants listed belowcan be
			    used as indices to refer to the corresponding registers.

			      SS
			      UESP
			      EFL
			      CS
			      EIP
			      ERR
			      TRAPNO
			      EAX
			      ECX
			      EDX
			      EBX
			      ESP
			      EBP
			      ESI
			      EDI
			      DS
			      ES
			      GS

			    The preceding constants are listed in <sys/regset.h>.

			    Note that a 32-bit process can run on an x86 64-bit system, using the
			    constants listed above.

       x86 (64-bit)	    To read the registers of a 32- or a  64-bit  process,  a  64-bit  x86
			    process should use the predefined constants listed below.

			      REG_GSBASE
			      REG_FSBASE
			      REG_DS
			      REG_ES
			      REG_GS
			      REG_FS
			      REG_SS
			      REG_RSP
			      REG_RFL
			      REG_CS
			      REG_RIP
			      REG_ERR
			      REG_TRAPNO
			      REG_RAX
			      REG_RCX
			      REG_RDX
			      REG_RBX
			      REG_RBP
			      REG_RSI
			      REG_RDI
			      REG_R8
			      REG_R9
			      REG_R10
			      REG_R11
			      REG_R12
			      REG_R13
			      REG_R14
			      REG_R15

			    The preceding constants are listed in <sys/regset.h>.

       pr_fpreg is a structure holding the contents of the floating-point registers.

       SPARC  registers, both general and floating-point, as seen by a 64-bit controlling process
       are the V9 versions of the registers, even if the target process is a 32-bit (V8) process.
       V8 registers are a subset of the V9 registers.

       If the lwp is not stopped, all register values are undefined.

   psinfo
       Contains  miscellaneous information about the process and the representative lwp needed by
       the ps(1) command. psinfo remains accessible after a process becomes a  zombie.	The  file
       contains  a  psinfo structure which contains an embedded lwpsinfo structure for the repre-
       sentative lwp, as follows:

	 typedef struct psinfo {
	     int pr_flag;	      /* process flags (DEPRECATED: see below) */
	     int pr_nlwp;	      /* number of active lwps in the process */
	     int pr_nzomb;	      /* number of zombie lwps in the process */
	     pid_t pr_pid;	      /* process id */
	     pid_t pr_ppid;	      /* process id of parent */
	     pid_t pr_pgid;	      /* process id of process group leader */
	     pid_t pr_sid;	      /* session id */
	     uid_t pr_uid;	      /* real user id */
	     uid_t pr_euid;	      /* effective user id */
	     gid_t pr_gid;	      /* real group id */
	     gid_t pr_egid;	      /* effective group id */
	     uintptr_t pr_addr;       /* address of process */
	     size_t pr_size;	      /* size of process image in Kbytes */
	     size_t pr_rssize;	      /* resident set size in Kbytes */
	     dev_t pr_ttydev;	      /* controlling tty device (or PRNODEV) */
	     ushort_t pr_pctcpu;      /* % of recent cpu time used by all lwps */
	     ushort_t pr_pctmem;      /* % of system memory used by process */
	     timestruc_t pr_start;    /* process start time, from the epoch */
	     timestruc_t pr_time;     /* cpu time for this process */
	     timestruc_t pr_ctime;    /* cpu time for reaped children */
	     char pr_fname[PRFNSZ];   /* name of exec'ed file */
	     char pr_psargs[PRARGSZ]; /* initial characters of arg list */
	     int pr_wstat;	      /* if zombie, the wait() status */
	     int pr_argc;	      /* initial argument count */
	     uintptr_t pr_argv;       /* address of initial argument vector */
	     uintptr_t pr_envp;       /* address of initial environment vector */
	     char pr_dmodel;	      /* data model of the process */
	     lwpsinfo_t pr_lwp;       /* information for representative lwp */
	     taskid_t pr_taskid;      /* task id */
	     projid_t pr_projid;      /* project id */
	     poolid_t pr_poolid;      /* pool id */
	     zoneid_t pr_zoneid;      /* zone id */
	     ctid_t pr_contract;      /* process contract id */
	 } psinfo_t;

       Some of the entries in psinfo, such as pr_addr, refer to internal kernel  data  structures
       and should not be expected to retain their meanings across different versions of the oper-
       ating system.

       psinfo_t.pr_flag is a deprecated interface that should no  longer  be  used.  Applications
       currently  relying  on  the SSYS bit in pr_flag should migrate to checking PR_ISSYS in the
       pstatus structure's pr_flags field.

       pr_pctcpu and pr_pctmem are 16-bit binary fractions in the  range  0.0  to  1.0	with  the
       binary  point  to the right of the high-order bit (1.0 == 0x8000). pr_pctcpu is the summa-
       tion over all lwps in the process.

       pr_lwp contains the ps(1) information for the representative lwp. If the process is a zom-
       bie,  pr_nlwp,  pr_nzomb,  and pr_lwp.pr_lwpid are zero and the other fields of pr_lwp are
       undefined:

	 typedef struct lwpsinfo {
	     int pr_flag;	      /* lwp flags (DEPRECATED: see below) */
	     id_t pr_lwpid;	      /* lwp id */
	     uintptr_t pr_addr;       /* internal address of lwp */
	     uintptr_t pr_wchan;      /* wait addr for sleeping lwp */
	     char pr_stype;	      /* synchronization event type */
	     char pr_state;	      /* numeric lwp state */
	     char pr_sname;	      /* printable character for pr_state */
	     char pr_nice;	      /* nice for cpu usage */
	     short pr_syscall;	      /* system call number (if in syscall) */
	     char pr_oldpri;	      /* pre-SVR4, low value is high priority */
	     char pr_cpu;	      /* pre-SVR4, cpu usage for scheduling */
	     int pr_pri;	      /* priority, high value = high priority */
	     ushort_t pr_pctcpu;      /* % of recent cpu time used by this lwp */
	     timestruc_t pr_start;    /* lwp start time, from the epoch */
	     timestruc_t pr_time;     /* cpu time for this lwp */
	     char pr_clname[PRCLSZ];  /* scheduling class name */
	     char pr_name[PRFNSZ];    /* name of system lwp */
	     processorid_t pr_onpro;  /* processor which last ran this lwp */
	     processorid_t pr_bindpro;/* processor to which lwp is bound */
	     psetid_t pr_bindpset;    /* processor set to which lwp is bound */
	     lgrp_id_t pr_lgrp		/* home lgroup */
	 } lwpsinfo_t;

       Some of the entries in lwpsinfo,  such  as  pr_addr,  pr_wchan,	pr_stype,  pr_state,  and
       pr_name,  refer	to  internal  kernel data structures and should not be expected to retain
       their meanings across different versions of the operating system.

       lwpsinfo_t.pr_flag is a deprecated interface that should no longer be used.

       pr_pctcpu is a 16-bit binary fraction, as described above. It represents the CPU time used
       by  the	specific  lwp. On a multi-processor machine, the maximum value is 1/N, where N is
       the number of CPUs.

       pr_contract is the id of the process contract of which the process is a member.	See  con-
       tract(4) and process(4).

   cred
       Contains a description of the credentials associated with the process:

	 typedef struct prcred {
	      uid_t pr_euid;	  /* effective user id */
	      uid_t pr_ruid;	  /* real user id */
	      uid_t pr_suid;	  /* saved user id (from exec) */
	      gid_t pr_egid;	  /* effective group id */
	      gid_t pr_rgid;	  /* real group id */
	      gid_t pr_sgid;	  /* saved group id (from exec) */
	      int pr_ngroups;	  /* number of supplementary groups */
	      gid_t pr_groups[1]; /* array of supplementary groups */
	 } prcred_t;

       The  array of associated supplementary groups in pr_groups is of variable length; the cred
       file contains all of the supplementary groups. pr_ngroups indicates the number of  supple-
       mentary groups. (See also the PCSCRED and PCSCREDX control operations.)

   priv
       Contains a description of the privileges associated with the process:

	 typedef struct prpriv {
	      uint32_t	      pr_nsets;      /* number of privilege set */
	      uint32_t	      pr_setsize;    /* size of privilege set */
	      uint32_t	      pr_infosize;   /* size of supplementary data */
	      priv_chunk_t    pr_sets[1];    /* array of sets */
	 } prpriv_t;

       The actual dimension of the pr_sets[] field is

	 pr_sets[pr_nsets][pr_setsize]

       which  is  followed by additional information about the process state pr_infosize bytes in
       size.

       The full size of the structure can be computed using PRIV_PRPRIV_SIZE(prpriv_t *).

   sigact
       Contains an array of sigaction structures describing the current dispositions of all  sig-
       nals  associated  with the traced process (see sigaction(2)). Signal numbers are displaced
       by 1 from array indices, so that the action for signal number n appears in position n-1 of
       the array.

   auxv
       Contains  the  initial values of the process's aux vector in an array of auxv_t structures
       (see <sys/auxv.h>). The values are those that were  passed  by  the  operating  system  as
       startup information to the dynamic linker.

   ldt
       This  file  exists  only  on  x86-based	machines. It is non-empty only if the process has
       established a local descriptor table (LDT). If non-empty, the file contains the	array  of
       currently  active  LDT  entries	in  an	array  of elements of type struct ssd, defined in
       <sys/sysi86.h>, one element for each active LDT entry.

   map, xmap
       Contain information about the virtual address map of the process. The map file contains an
       array of prmap structures while the xmap file contains an array of prxmap structures. Each
       structure describes a contiguous virtual address region in the address space of the traced
       process:

	 typedef struct prmap {
	      uintptr_tpr_vaddr;	 /* virtual address of mapping */
	      size_t pr_size;		 /* size of mapping in bytes */
	      char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
	      offset_t pr_offset;	 /* offset into mapped object, if any */
	      int pr_mflags;		 /* protection and attribute flags */
	      int pr_pagesize;		 /* pagesize for this mapping in bytes */
	      int pr_shmid;		 /* SysV shared memory identifier */
	 } prmap_t;

	 typedef struct prxmap {
	      uintptr_t pr_vaddr;	 /* virtual address of mapping */
	      size_t pr_size;		 /* size of mapping in bytes */
	      char pr_mapname[PRMAPSZ];  /* name in /proc/pid/object */
	      offset_t pr_offset;	 /* offset into mapped object, if any */
	      int pr_mflags;		 /* protection and attribute flags */
	      int pr_pagesize;		 /* pagesize for this mapping in bytes */
	      int pr_shmid;		 /* SysV shared memory identifier */
	      dev_t pr_dev;		 /* device of mapped object, if any */
	      uint64_t pr_ino;		 /* inode of mapped object, if any */
	      size_t pr_rss;		 /* pages of resident memory */
	      size_t pr_anon;		 /* pages of resident anonymous memory */
	      size_t pr_locked; 	 /* pages of locked memory */
	      uint64_t pr_hatpagesize;	 /* pagesize of mapping */
	 } prxmap_t;

       pr_vaddr  is  the  virtual address of the mapping within the traced process and pr_size is
       its size in bytes. pr_mapname, if it does not contain a null string, contains the name  of
       a  file	in the object directory (see below) that can be opened read-only to obtain a file
       descriptor for the mapped file associated with the mapping. This  enables  a  debugger  to
       find  object  file  symbol  tables  without having to know the real path names of the exe-
       cutable file and shared libraries of the process. pr_offset is the  64-bit  offset  within
       the mapped file (if any) to which the virtual address is mapped.

       pr_mflags is a bit-mask of protection and attribute flags:

       MA_READ		mapping is readable by the traced process.

       MA_WRITE 	mapping is writable by the traced process.

       MA_EXEC		mapping is executable by the traced process.

       MA_SHARED	mapping changes are shared by the mapped object.

       MA_ISM		mapping is intimate shared memory (shared MMU resources)

       MAP_NORESERVE	mapping does not have swap space reserved (mapped with MAP_NORESERVE)

       MA_SHM		mapping System V shared memory

       A contiguous area of the address space having the same underlying mapped object may appear
       as multiple mappings due to varying read, write, and execute  attributes.  The  underlying
       mapped  object  does  not change over the range of a single mapping. An I/O operation to a
       mapping marked MA_SHARED fails if applied at a virtual  address	not  corresponding  to	a
       valid  page  in	the  underlying mapped object. A write to a MA_SHARED mapping that is not
       marked MA_WRITE fails. Reads and writes to private  mappings  always  succeed.  Reads  and
       writes to unmapped addresses fail.

       pr_pagesize is the page size for the mapping, currently always the system pagesize.

       pr_shmid  is the shared memory identifier, if any, for the mapping. Its value is -1 if the
       mapping is not System V shared memory. See shmget(2).

       pr_dev is the device of the mapped object, if any, for the mapping. Its value  is  PRNODEV
       (-1) if the mapping does not have a device.

       pr_ino  is  the inode of the mapped object, if any, for the mapping. Its contents are only
       valid if pr_dev is not PRNODEV.

       pr_rss is the number of resident pages of memory for the mapping. The number  of  resident
       bytes  for  the	mapping may be determined by multiplying pr_rss by the page size given by
       pr_pagesize.

       pr_anon is the number of resident anonymous memory pages (pages which are private to  this
       process) for the mapping.

       pr_locked is the number of locked pages for the mapping. Pages which are locked are always
       resident in memory.

       pr_hatpagesize is the size, in bytes, of  the  HAT  (MMU)  translation  for  the  mapping.
       pr_hatpagesize  may be different than pr_pagesize. The possible values are hardware archi-
       tecture specific, and may change over a mapping's lifetime.

   rmap
       Contains information about the reserved address ranges of the process. The  file  contains
       an  array of prmap structures, as defined above for the map file. Each structure describes
       a contiguous virtual address region in the address space of the	traced	process  that  is
       reserved  by  the  system  in  the sense that an mmap(2) system call that does not specify
       MAP_FIXED will not use any part of it for the new mapping. Examples of  such  reservations
       include the address ranges reserved for the process stack and the individual thread stacks
       of a multi-threaded process.

   cwd
       A symbolic link to the process's current working directory. See chdir(2). A readlink(2) of
       /proc/pid/cwd  yields  a null string. However, it can be opened, listed, and searched as a
       directory, and can be the target of chdir(2).

   root
       A symbolic link to the process's root directory. /proc/pid/root can differ from the system
       root directory if the process or one of its ancestors executed chroot(2) as super user. It
       has the same semantics as /proc/pid/cwd.

   fd
       A directory containing references to the open files of the process. Each entry is a  deci-
       mal number corresponding to an open file descriptor in the process.

       If  an  entry refers to a regular file, it can be opened with normal file system semantics
       but, to ensure that the controlling process cannot gain greater access than the controlled
       process,  with no file access modes other than its read/write open modes in the controlled
       process. If an entry refers to a directory, it can be accessed with the same semantics  as
       /proc/pid/cwd. An attempt to open any other type of entry fails with EACCES.

   object
       A  directory containing read-only files with names corresponding to the pr_mapname entries
       in the map and pagedata files. Opening such a file yields a file descriptor for the under-
       lying  mapped  file associated with an address-space mapping in the process. The file name
       a.out appears in the directory as an alias for the process's executable file.

       The object directory makes it possible for a controlling process to  gain  access  to  the
       object  file  and any shared libraries (and consequently the symbol tables) without having
       to know the actual path names of the executable files.

   path
       A directory containing symbolic links to  files	opened	by  the  process.  The	directory
       includes  one  entry  for  cwd and root. The directory also contains a numerical entry for
       each file descriptor in the fd directory, and entries matching those in the object  direc-
       tory.  If  this information is not available, any attempt to read the contents of the sym-
       bolic link will fail. This is most common for files that do not exist  in  the  filesystem
       namespace (such as FIFOs and sockets), but can also happen for regular files. For the file
       descriptor entries, the path may be different from the one used by the process to open the
       file.

   pagedata
       Opening	the page data file enables tracking of address space references and modifications
       on a per-page basis.

       A read(2) of the page data file descriptor returns structured  page  data  and  atomically
       clears  the  page  data	maintained  for the file by the system. That is to say, each read
       returns data collected since the last read; the first read returns  data  collected  since
       the  file  was  opened.	When  the  call completes, the read buffer contains the following
       structure as its header and thereafter contains a number of section header structures  and
       associated byte arrays that must be accessed by walking linearly through the buffer.

	 typedef struct prpageheader {
	     timestruc_t pr_tstamp; /* real time stamp, time of read() */
	     ulong_t pr_nmap;	    /* number of address space mappings */
	     ulong_t pr_npage;	    /* total number of pages */
	 } prpageheader_t;

       The  header  is	followed  by  pr_nmap  prasmap structures and associated data arrays. The
       prasmap structure contains the following elements:

	 typedef struct prasmap {
	     uintptr_t pr_vaddr;	/* virtual address of mapping */
	     ulong_t pr_npage;		/* number of pages in mapping */
	     char pr_mapname[PRMAPSZ];	/* name in /proc/pid/object */
	     offset_t pr_offset;	/* offset into mapped object, if any */
	     int pr_mflags;		/* protection and attribute flags */
	     int pr_pagesize;		/* pagesize for this mapping in bytes */
	     int pr_shmid;		/* SysV shared memory identifier */
	 } prasmap_t;

       Each section header is followed by pr_npage bytes, one byte for each page in the  mapping,
       plus  0-7 null bytes at the end so that the next prasmap structure begins on an eight-byte
       aligned boundary. Each data byte may contain these flags:

       PG_REFERENCED	page has been referenced.

       PG_MODIFIED	page has been modified.

       If the read buffer is not large enough to contain all of the page  data,  the  read  fails
       with  E2BIG  and the page data is not cleared. The required size of the read buffer can be
       determined through fstat(2). Application of lseek(2) to the page data file  descriptor  is
       ineffective;  every read starts from the beginning of the file. Closing the page data file
       descriptor terminates the system overhead associated with collecting the data.

       More than one page data file descriptor for the same process can be opened, up to  a  sys-
       tem-imposed  limit  per	traced process. A read of one does not affect the data being col-
       lected by the system for the others. An open of the page data file will fail  with  ENOMEM
       if the system-imposed limit would be exceeded.

   watch
       Contains  an  array  of	prwatch  structures, one for each watched area established by the
       PCWATCH control operation. See PCWATCH for details.

   usage
       Contains process usage information described by a  prusage  structure  which  contains  at
       least the following fields:

	 typedef struct prusage {
	     id_t pr_lwpid;	      /* lwp id.  0: process or defunct */
	     int pr_count;	      /* number of contributing lwps */
	     timestruc_t pr_tstamp;   /* real time stamp, time of read() */
	     timestruc_t pr_create;   /* process/lwp creation time stamp */
	     timestruc_t pr_term;     /* process/lwp termination time stamp */
	     timestruc_t pr_rtime;    /* total lwp real (elapsed) time */
	     timestruc_t pr_utime;    /* user level CPU time */
	     timestruc_t pr_stime;    /* system call CPU time */
	     timestruc_t pr_ttime;    /* other system trap CPU time */
	     timestruc_t pr_tftime;   /* text page fault sleep time */
	     timestruc_t pr_dftime;   /* data page fault sleep time */
	     timestruc_t pr_kftime;   /* kernel page fault sleep time */
	     timestruc_t pr_ltime;    /* user lock wait sleep time */
	     timestruc_t pr_slptime;  /* all other sleep time */
	     timestruc_t pr_wtime;    /* wait-cpu (latency) time */
	     timestruc_t pr_stoptime; /* stopped time */
	     ulong_t pr_minf;	      /* minor page faults */
	     ulong_t pr_majf;	      /* major page faults */
	     ulong_t pr_nswap;	      /* swaps */
	     ulong_t pr_inblk;	      /* input blocks */
	     ulong_t pr_oublk;	      /* output blocks */
	     ulong_t pr_msnd;	      /* messages sent */
	     ulong_t pr_mrcv;	      /* messages received */
	     ulong_t pr_sigs;	      /* signals received */
	     ulong_t pr_vctx;	      /* voluntary context switches */
	     ulong_t pr_ictx;	      /* involuntary context switches */
	     ulong_t pr_sysc;	      /* system calls */
	     ulong_t pr_ioch;	      /* chars read and written */
	 } prusage_t;

       Microstate  accounting  is now continuously enabled. While this information was previously
       an estimate, if microstate accounting were not enabled, the  current  information  is  now
       never an estimate represents time the process has spent in various states.

   lstatus
       Contains  a  prheader structure followed by an array of lwpstatus structures, one for each
       active lwp in the process (see also /proc/pid/lwp/lwpid/lwpstatus,  below).  The  prheader
       structure describes the number and size of the array entries that follow.

	 typedef struct prheader {
	     long pr_nent;	  /* number of entries */
	     size_t pr_entsize;   /* size of each entry, in bytes */
	 } prheader_t;

       The lwpstatus structure may grow by the addition of elements at the end in future releases
       of the system. Programs must use pr_entsize in the file header to index through the array.
       These  comments	apply  to  all /proc files that include a prheader structure (lpsinfo and
       lusage, below).

   lpsinfo
       Contains a prheader structure followed by an array of lwpsinfo structures, one for eachac-
       tive and zombie lwp in the process. See also /proc/pid/lwp/lwpid/lwpsinfo, below.

   lusage
       Contains  a  prheader  structure  followed by an array of prusage structures, one for each
       active lwp in the process, plus an additional element at the beginning that  contains  the
       summation  over	all  defunct  lwps  (lwps  that  once  existed but no longer exist in the
       process). Excluding the pr_lwpid, pr_tstamp, pr_create, and pr_term entries, the entry-by-
       entry  summation over all these structures is the definition of the process usage informa-
       tion obtained from the usage file. (See also /proc/pid/lwp/lwpid/lwpusage, below.)

   lwp
       A directory containing entries each of which names an active  or  zombie  lwp  within  the
       process. These entries are themselves directories containing additional files as described
       below. Only the lwpsinfo file exists in the directory of a zombie lwp.

STRUCTURE OF /proc/pid/lwp/ lwpid
       A given directory /proc/pid/lwp/lwpid contains the following entries:

   lwpctl
       Write-only control file. The messages written to this file affect the specific lwp  rather
       than the representative lwp, as is the case for the process's ctl file.

   lwpstatus
       lwp-specific  state  information.  This file contains the lwpstatus structure for the spe-
       cific lwp as described above for the representative lwp in the process's status file.

   lwpsinfo
       lwp-specific ps(1) information. This file contains the lwpsinfo structure for the specific
       lwp  as	described  above  for  the  representative  lwp in the process's psinfo file. The
       lwpsinfo file remains accessible after an lwp becomes a zombie.

   lwpusage
       This file contains the prusage structure for the specific lwp as described above  for  the
       process's usage file.

   gwindows
       This  file  exists  only  on SPARC based machines. If it is non-empty, it contains a gwin-
       dows_t structure, defined in <sys/regset.h>, with the values of those SPARC register  win-
       dows  that  could  not be stored on the stack when the lwp stopped. Conditions under which
       register windows are not stored on the stack are: the stack pointer refers to  nonexistent
       process memory or the stack pointer is improperly aligned. If the lwp is not stopped or if
       there are no register windows that could not be stored on the stack,  the  file	is  empty
       (the usual case).

   xregs
       Extra  state  registers. The extra state register set is architecture dependent; this file
       is empty if the system does not support extra state registers. If the file  is  non-empty,
       it   contains  an  architecture	dependent  structure  of  type	prxregset_t,  defined  in
       <procfs.h>, with the values of the lwp's extra state registers. If the lwp is not stopped,
       all register values are undefined. See also the PCSXREG control operation, below.

   asrs
       This  file  exists  only for 64-bit SPARC V9 processes. It contains an asrset_t structure,
       defined in <sys/regset.h>, containing the values of the lwp's platform-dependent ancillary
       state  registers.  If  the lwp is not stopped, all register values are undefined. See also
       the PCSASRS control operation, below.

   templates
       A directory which contains references to the active templates for the lwp,  named  by  the
       contract  type.	Changes  made to an active template descriptor do not affect the original
       template which was activated, though they do affect the active template. It is not  possi-
       ble to activate an active template descriptor. See contract(4).

CONTROL MESSAGES
       Process	state changes are effected through messages written to a process's ctl file or to
       an individual lwp's lwpctl file. All control messages consist of a  long  that  names  the
       specific operation followed by additional data containing the operand, if any.

       Multiple control messages may be combined in a single write(2) (or writev(2)) to a control
       file, but no partial writes are permitted. That is, each control message,  operation  code
       plus  operand, if any, must be presented in its entirety to the write(2) and not in pieces
       over several system calls. If a control operation fails,  no  subsequent  operations  con-
       tained in the same write(2) are attempted.

       Descriptions  of the allowable control messages follow. In all cases, writing a message to
       a control file for a process or lwp that has terminated elicits the error ENOENT.

   PCSTOP PCDSTOP PCWSTOP PCTWSTOP
       When applied to the process control file, PCSTOP directs all lwps to stop  and  waits  for
       them  to stop, PCDSTOP directs all lwps to stop without waiting for them to stop, and PCW-
       STOP simply waits for all lwps to stop. When  applied  to  an  lwp  control  file,  PCSTOP
       directs	the specific lwp to stop and waits until it has stopped, PCDSTOP directs the spe-
       cific lwp to stop without waiting for it to stop, and PCWSTOP simply waits  for	the  spe-
       cific  lwp  to stop. When applied to an lwp control file, PCSTOP and PCWSTOP complete when
       the lwp stops on an event of interest, immediately if already so stopped; when applied  to
       the  process  control file, they complete when every lwp has stopped either on an event of
       interest or on a PR_SUSPENDED stop.

       PCTWSTOP is identical to PCWSTOP except that it enables the  operation  to  time  out,  to
       avoid  waiting  forever	for a process or lwp that may never stop on an event of interest.
       PCTWSTOP takes a long operand specifying a number of milliseconds; the wait will terminate
       successfully after the specified number of milliseconds even if the process or lwp has not
       stopped; a timeout value of zero makes the operation identical to PCWSTOP.

       An ``event of interest'' is either a PR_REQUESTED stop or a stop that has  been	specified
       in the process's tracing flags (set by PCSTRACE, PCSFAULT, PCSENTRY, and PCSEXIT). PR_JOB-
       CONTROL and PR_SUSPENDED stops are specifically not events of interest. (An lwp	may  stop
       twice  due  to a stop signal, first showing PR_SIGNALLED if the signal is traced and again
       showing PR_JOBCONTROL if the lwp is set running without clearing the signal.) If PCSTOP or
       PCDSTOP	is  applied  to an lwp that is stopped, but not on an event of interest, the stop
       directive takes effect when the lwp is restarted by the competing mechanism. At that time,
       the lwp enters a PR_REQUESTED stop before executing any user-level code.

       A  write  of a control message that blocks is interruptible by a signal so that, for exam-
       ple, an alarm(2) can be set to avoid waiting forever for a process or lwp that  may  never
       stop  on an event of interest. If PCSTOP is interrupted, the lwp stop directives remain in
       effect even though the write(2) returns an error. (Use of PCTWSTOP with a non-zero timeout
       is recommended over PCWSTOP with an alarm(2).)

       A  system  process  (indicated  by the PR_ISSYS flag) never executes at user level, has no
       user-level address space visible through /proc, and cannot be  stopped.	Applying  one  of
       these operations to a system process or any of its lwps elicits the error EBUSY.

   PCRUN
       Make  an  lwp  runnable again after a stop. This operation takes a long operand containing
       zero or more of the following flags:

       PRCSIG	   clears the current signal, if any (see PCCSIG).

       PRCFAULT    clears the current fault, if any (see PCCFAULT).

       PRSTEP	   directs the lwp to execute a single machine instruction. On completion of  the
		   instruction,  a trace trap occurs. If FLTTRACE is being traced, the lwp stops;
		   otherwise, it is sent SIGTRAP. If SIGTRAP is being traced and is not  blocked,
		   the	lwp  stops.  When  the lwp stops on an event of interest, the single-step
		   directive is cancelled, even if the stop occurs before the instruction is exe-
		   cuted.  This  operation requires hardware and operating system support and may
		   not be implemented on all processors. It is implemented on SPARC and x86-based
		   machines.

       PRSABORT    is meaningful only if the lwp is in a PR_SYSENTRY stop or is marked PR_ASLEEP;
		   it instructs the lwp to abort execution of the system call (see  PCSENTRY  and
		   PCSEXIT).

       PRSTOP	   directs  the  lwp  to  stop again as soon as possible after resuming execution
		   (see PCDSTOP). In particular,  if  the  lwp	is  stopped  on  PR_SIGNALLED  or
		   PR_FAULTED,	the  next  stop  will  show PR_REQUESTED, no other stop will have
		   intervened, and the lwp will not have executed any user-level code.

       When applied to an lwp control file, PCRUN clears any  outstanding  directed-stop  request
       and makes the specific lwp runnable. The operation fails with EBUSY if the specific lwp is
       not stopped on an event of interest or has not been directed to stop or if the  agent  lwp
       exists and this is not the agent lwp (see PCAGENT).

       When applied to the process control file, a representative lwp is chosen for the operation
       as described for /proc/pid/status. The operation fails with EBUSY  if  the  representative
       lwp  is	not  stopped  on  an event of interest or has not been directed to stop or if the
       agent lwp exists. If PRSTEP or PRSTOP  was  requested,  the  representative  lwp  is  made
       runnable  and  its outstanding directed-stop request is cleared; otherwise all outstanding
       directed-stop requests are cleared and, if it was stopped on an	event  of  interest,  the
       representative  lwp  is	marked	PR_REQUESTED.  If,  as a consequence, all lwps are in the
       PR_REQUESTED or PR_SUSPENDED stop state, all lwps showing PR_REQUESTED are made runnable.

   PCSTRACE
       Define a set of signals to be traced in the process. The receipt of one of  these  signals
       by  an lwp causes the lwp to stop. The set of signals is defined using an operand sigset_t
       contained in the control message. Receipt of SIGKILL cannot be traced; if specified, it is
       silently ignored.

       If  a signal that is included in an lwp's held signal set (the signal mask) is sent to the
       lwp, the signal is not received and does not cause a stop until it  is  removed	from  the
       held signal set, either by the lwp itself or by setting the held signal set with PCSHOLD.

   PCCSIG
       The current signal, if any, is cleared from the specific or representative lwp.

   PCSSIG
       The  current  signal and its associated signal information for the specific or representa-
       tive lwp are set according to the contents of the operand siginfo structure (see <sys/sig-
       info.h>).  If  the  specified  signal  number  is zero, the current signal is cleared. The
       semantics of this operation are different from those of kill(2)	in  that  the  signal  is
       delivered  to the lwp immediately after execution is resumed (even if it is being blocked)
       and an additional PR_SIGNALLED stop does not intervene even if the signal is traced.  Set-
       ting the current signal to SIGKILL terminates the process immediately.

   PCKILL
       If  applied  to	the  process control file, a signal is sent to the process with semantics
       identical to those of kill(2). If applied to an lwp control file,  a  directed  signal  is
       sent  to the specific lwp. The signal is named in a long operand contained in the message.
       Sending SIGKILL terminates the process immediately.

   PCUNKILL
       A signal is deleted, that is, it is removed from the set of pending signals. If applied to
       the  process  control  file,  the signal is deleted from the process's pending signals. If
       applied to an lwp control file, the signal is deleted from the lwp's pending signals.  The
       current	signal	(if any) is unaffected. The signal is named in a long operand in the con-
       trol message. It is an error (EINVAL) to attempt to delete SIGKILL.

   PCSHOLD
       Set the set of held signals for the specific or representative lwp (signals whose delivery
       will be blocked if sent to the lwp). The set of signals is specified with a sigset_t oper-
       and. SIGKILL and SIGSTOP cannot be held; if specified, they are silently ignored.

   PCSFAULT
       Define a set of hardware faults to be traced in the process. On	incurring  one	of  these
       faults,	an  lwp stops. The set is defined via the operand fltset_t structure. Fault names
       are defined in <sys/fault.h> and include the following. Some of these may not occur on all
       processors; there may be processor-specific faults in addition to these.

       FLTILL	    illegal instruction

       FLTPRIV	    privileged instruction

       FLTBPT	    breakpoint trap

       FLTTRACE     trace trap (single-step)

       FLTWATCH     watchpoint trap

       FLTACCESS    memory access fault (bus error)

       FLTBOUNDS    memory bounds violation

       FLTIOVF	    integer overflow

       FLTIZDIV     integer zero divide

       FLTFPE	    floating-point exception

       FLTSTACK     unrecoverable stack fault

       FLTPAGE	    recoverable page fault

       When  not  traced,  a  fault  normally  results in the posting of a signal to the lwp that
       incurred the fault. If an lwp stops on a fault, the signal is posted to the lwp when  exe-
       cution  is  resumed  unless  the fault is cleared by PCCFAULT or by the PRCFAULT option of
       PCRUN. FLTPAGE is an exception; no signal is posted. The pr_info field  in  the	lwpstatus
       structure identifies the signal to be sent and contains machine-specific information about
       the fault.

   PCCFAULT
       The current fault, if any, is cleared; the associated signal will not be sent to the  spe-
       cific or representative lwp.

   PCSENTRY PCSEXIT
       These  control  operations  instruct  the  process's lwps to stop on entry to or exit from
       specified system calls. The set of system calls to be traced is	defined  via  an  operand
       sysset_t structure.

       When  entry  to a system call is being traced, an lwp stops after having begun the call to
       the system but before the system call arguments have been fetched from the lwp. When  exit
       from  a	system	call  is being traced, an lwp stops on completion of the system call just
       prior to checking for signals and returning to user level. At this point, all return  val-
       ues have been stored into the lwp's registers.

       If an lwp is stopped on entry to a system call (PR_SYSENTRY) or when sleeping in an inter-
       ruptible system call (PR_ASLEEP is set), it may be instructed to  go  directly  to  system
       call exit by specifying the PRSABORT flag in a PCRUN control message. Unless exit from the
       system call is being traced, the lwp returns to user level showing EINTR.

   PCWATCH
       Set or clear a watched area in the controlled process from a prwatch structure operand:

	 typedef struct prwatch {
	     uintptr_t pr_vaddr;  /* virtual address of watched area */
	     size_t pr_size;	  /* size of watched area in bytes */
	     int pr_wflags;	  /* watch type flags */
	 } prwatch_t;

       pr_vaddr specifies the virtual address of an area of memory to  be  watched  in	the  con-
       trolled process. pr_size specifies the size of the area, in bytes. pr_wflags specifies the
       type of memory access to be monitored as a bit-mask of the following flags:

       WA_READ	       read access

       WA_WRITE        write access

       WA_EXEC	       execution access

       WA_TRAPAFTER    trap after the instruction completes

       If pr_wflags is non-empty, a watched area is established for  the  virtual  address  range
       specified  by  pr_vaddr	and  pr_size.  If  pr_wflags is empty, any previously-established
       watched area starting at the specified virtual address is cleared; pr_size is ignored.

       A watchpoint is triggered when an lwp in the traced process makes a memory reference  that
       covers  at  least  one  byte of a watched area and the memory reference is as specified in
       pr_wflags. When an lwp triggers a watchpoint, it incurs a watchpoint trap. If FLTWATCH  is
       being  traced,  the lwp stops; otherwise, it is sent a SIGTRAP signal; if SIGTRAP is being
       traced and is not blocked, the lwp stops.

       The watchpoint trap occurs before the instruction completes unless WA_TRAPAFTER was speci-
       fied, in which case it occurs after the instruction completes. If it occurs before comple-
       tion, the memory is not modified. If it occurs after completion, the  memory  is  modified
       (if the access is a write access).

       Physical i/o is an exception for watchpoint traps. In this instance, there is no guarantee
       that memory before the watched area has already been modified (or in the case  of  WA_TRA-
       PAFTER,	that the memory following the watched area has not been modified) when the watch-
       point trap occurs and the lwp stops.

       pr_info in the lwpstatus structure contains information pertinent to the watchpoint  trap.
       In particular, the si_addr field contains the virtual address of the memory reference that
       triggered the watchpoint, and the si_code field contains one of TRAP_RWATCH,  TRAP_WWATCH,
       or  TRAP_XWATCH, indicating read, write, or execute access, respectively. The si_trapafter
       field is zero unless WA_TRAPAFTER is in effect for this watched area;  non-zero	indicates
       that the current instruction is not the instruction that incurred the watchpoint trap. The
       si_pc field contains the virtual address of the instruction that incurred the trap.

       A watchpoint trap may be triggered while executing a system call that makes  reference  to
       the  traced  process's memory. The lwp that is executing the system call incurs the watch-
       point trap while still in the system call. If it stops as a result, the	lwpstatus  struc-
       ture contains the system call number and its arguments. If the lwp does not stop, or if it
       is set running again without clearing the signal or fault,  the	system	call  fails  with
       EFAULT.	If  WA_TRAPAFTER  was specified, the memory reference will have completed and the
       memory will have been modified (if the access was a write access) when the watchpoint trap
       occurs.

       If  more than one of WA_READ, WA_WRITE, and WA_EXEC is specified for a watched area, and a
       single instruction incurs more than one of the specified types, only one is reported  when
       the  watchpoint	trap  occurs.  The  precedence is WA_EXEC, WA_READ, WA_WRITE (WA_EXEC and
       WA_READ take precedence over WA_WRITE), unless WA_TRAPAFTER was specified, in  which  case
       it is WA_WRITE, WA_READ, WA_EXEC (WA_WRITE takes precedence).

       PCWATCH fails with EINVAL if an attempt is made to specify overlapping watched areas or if
       pr_wflags contains flags other than those specified above. It  fails  with  ENOMEM  if  an
       attempt	is  made  to establish more watched areas than the system can support (the system
       can support thousands).

       The child of a vfork(2) borrows the parent's address space. When a vfork(2) is executed by
       a  traced  process,  all  watched areas established for the parent are suspended until the
       child terminates or performs an exec(2). Any watched areas  established	independently  in
       the  child are cancelled when the parent resumes after the child's termination or exec(2).
       PCWATCH fails with EBUSY if applied to the parent of a vfork(2) before the child has  ter-
       minated	or  performed  an exec(2). The PR_VFORKP flag is set in the pstatus structure for
       such a parent process.

       Certain accesses of the traced process's address space by the operating system are  immune
       to  watchpoints.  The initial construction of a signal stack frame when a signal is deliv-
       ered to an lwp will not trigger a watchpoint trap even if the  new  frame  covers  watched
       areas  of  the stack. Once the signal handler is entered, watchpoint traps occur normally.
       On SPARC based machines, register window overflow and underflow will  not  trigger  watch-
       point traps, even if the register window save areas cover watched areas of the stack.

       Watched	areas are not inherited by child processes, even if the traced process's inherit-
       on-fork mode, PR_FORK, is set (see PCSET, below). All watched areas are cancelled when the
       traced process performs a successful exec(2).

   PCSET PCUNSET
       PCSET  sets  one  or  more modes of operation for the traced process. PCUNSET unsets these
       modes. The modes to be set or unset are specified by flags in an operand long in the  con-
       trol message:

       PR_FORK	    (inherit-on-fork):	When set, the process's tracing flags and its inherit-on-
		    fork mode are inherited by the child of a  fork(2),  fork1(2),  or	vfork(2).
		    When unset, child processes start with all tracing flags cleared.

       PR_RLC	    (run-on-last-close):  When	set  and  the last writable /proc file descriptor
		    referring to the traced process or any of its lwps	is  closed,  all  of  the
		    process's  tracing	flags and watched areas are cleared, any outstanding stop
		    directives are canceled, and if any lwps are stopped on events  of	interest,
		    they  are  set  running as though PCRUN had been applied to them. When unset,
		    the process's tracing flags and watched areas are retained and lwps  are  not
		    set running on last close.

       PR_KLC	    (kill-on-last-close):  When  set  and the last writable /proc file descriptor
		    referring to the traced process or any of its lwps is closed, the process  is
		    terminated with SIGKILL.

       PR_ASYNC     (asynchronous-stop): When set, a stop on an event of interest by one lwp does
		    not directly affect any other lwp in the process. When unset and an lwp stops
		    on	an  event  of  interest  other	than  PR_REQUESTED, all other lwps in the
		    process are directed to stop.

       PR_MSACCT    (microstate accounting): Microstate accounting is now  continuously  enabled.
		    This flag is deprecated and no longer has any effect upon microstate account-
		    ing. Applications may toggle this flag; however, microstate  accounting  will
		    remain enabled regardless.

       PR_MSFORK    (inherit   microstate  accounting):  All  processes  now  inherit  microstate
		    accounting, as it is continuously enabled. This flag has been deprecated  and
		    its use no longer has any effect upon the behavior of microstate accounting.

       PR_BPTADJ    (breakpoint  trap  pc  adjustment):  On x86-based machines, a breakpoint trap
		    leaves the program counter (the EIP) referring to the  breakpointed  instruc-
		    tion plus one byte. When PR_BPTADJ is set, the system will adjust the program
		    counter back to the location of the breakpointed  instruction  when  the  lwp
		    stops on a breakpoint. This flag has no effect on SPARC based machines, where
		    breakpoint traps leave the program	counter  referring  to	the  breakpointed
		    instruction.

       PR_PTRACE    (ptrace-compatibility):  When  set,  a  stop  on  an event of interest by the
		    traced process is reported to the parent of the traced process  by	wait(3C),
		    SIGTRAP  is sent to the traced process when it executes a successful exec(2),
		    setuid/setgid flags are  not  honored  for	execs  performed  by  the  traced
		    process,  any  exec  of  an  object  file that the traced process cannot read
		    fails, and the process dies when its parent dies. This mode is deprecated; it
		    is	provided only to allow ptrace(3C) to be implemented as a library function
		    using /proc.

       It is an error (EINVAL) to specify flags other than those  described  above  or	to  apply
       these operations to a system process. The current modes are reported in the pr_flags field
       of /proc/pid/status and /proc/pid/lwp/lwp/lwpstatus.

   PCSREG
       Set the general registers for the specific or representative lwp according to the  operand
       prgregset_t structure.

       On  SPARC  based  systems,  only  the condition-code bits of the processor-status register
       (R_PSR) of SPARC V8 (32-bit) processes can be modified by PCSREG. Other privileged  regis-
       ters cannot be modified at all.

       On  x86-based  systems,	only  certain bits of the flags register (EFL) can be modified by
       PCSREG: these include the condition codes, direction-bit, and overflow-bit.

       PCSREG fails with EBUSY if the lwp is not stopped on an event of interest.

   PCSVADDR
       Set the address at which execution will resume for the specific or representative lwp from
       the  operand long. On SPARC based systems, both %pc and %npc are set, with %npc set to the
       instruction following the virtual  address.  On	x86-based  systems,  only  %eip  is  set.
       PCSVADDR fails with EBUSY if the lwp is not stopped on an event of interest.

   PCSFPREG
       Set  the  floating-point registers for the specific or representative lwp according to the
       operand prfpregset_t structure. An error (EINVAL) is returned if the system does not  sup-
       port floating-point operations (no floating-point hardware and the system does not emulate
       floating-point machine instructions). PCSFPREG fails with EBUSY if the lwp is not  stopped
       on an event of interest.

   PCSXREG
       Set  the  extra	state  registers  for the specific or representative lwp according to the
       architecture-dependent operand prxregset_t structure. An error (EINVAL) is returned if the
       system  does not support extra state registers. PCSXREG fails with EBUSY if the lwp is not
       stopped on an event of interest.

   PCSASRS
       Set the ancillary state registers for the specific or representative lwp according to  the
       SPARC  V9  platform-dependent operand asrset_t structure. An error (EINVAL) is returned if
       either the target process or the controlling process is not a  64-bit  SPARC  V9  process.
       Most  of  the  ancillary state registers are privileged registers that cannot be modified.
       Only those that can be modified are set; all others are silently  ignored.  PCSASRS  fails
       with EBUSY if the lwp is not stopped on an event of interest.

   PCAGENT
       Create  an  agent  lwp  in  the	controlled  process with register values from the operand
       prgregset_t structure (see PCSREG, above). The agent lwp is created in the  stopped  state
       showing	PR_REQUESTED  and  with  its held signal set (the signal mask) having all signals
       except SIGKILL and SIGSTOP blocked.

       The PCAGENT operation fails with EBUSY unless the process is fully stopped via /proc, that
       is,  unless  all of the lwps in the process are stopped either on events of interest or on
       PR_SUSPENDED, or are stopped on PR_JOBCONTROL and have been directed to stop via  PCDSTOP.
       It  fails  with	EBUSY  if  an  agent  lwp  already exists. It fails with ENOMEM if system
       resources for creating new lwps have been exhausted.

       Any PCRUN operation applied to the process control file or to the control file of  an  lwp
       other  than  the agent lwp fails with EBUSY as long as the agent lwp exists. The agent lwp
       must be caused to terminate by executing the SYS_lwp_exit  system  call	trap  before  the
       process can be restarted.

       Once the agent lwp is created, its lwp-ID can be found by reading the process status file.
       To facilitate opening the agent	lwp's  control	and  status  files,  the  directory  name
       /propc/pid/lwp/agent  is  accepted  for	lookup	operations  as	an  invisible  alias  for
       /proc/pid/lwp/lwpid, lwpid being the lwp-ID of the agent lwp (invisible in the sense  that
       the  name  ``agent'' does not appear in a directory listing of /proc/pid/lwp obtained from
       ls(1), getdents(2), or readdir(3C)).

       The purpose of the agent lwp is to perform operations in the controlled process on  behalf
       of  the controlling process: to gather information not directly available via /proc files,
       or in general to make the process change state in ways not directly  available  via  /proc
       control	operations.  To make use of an agent lwp, the controlling process must be capable
       of making it execute system calls (specifically, the SYS_lwp_exit system call  trap).  The
       register values given to the agent lwp on creation are typically the registers of the rep-
       resentative lwp, so that the agent lwp can use its stack.

       The agent lwp is not allowed to execute any variation of the SYS_fork or  SYS_exec  system
       call traps. Attempts to do so yield ENOTSUP to the agent lwp.

       Symbolic  constants  for system call trap numbers like SYS_lwp_exit and SYS_lwp_create can
       be found in the header file <sys/syscall.h>.

   PCREAD PCWRITE
       Read or write the target process's address space via a priovec structure operand:

	 typedef struct priovec {
	     void *pio_base;	  /* buffer in controlling process */
	     size_t pio_len;	  /* size of read/write request in bytes */
	     off_t pio_offset;	  /* virtual address in target process */
	 } priovec_t;

       These operations have the same effect as pread(2) and pwrite(2), respectively, of the tar-
       get  process's  address space file. The difference is that more than one PCREAD or PCWRITE
       control operation can be written to the control file at once, and they can be interspersed
       with  other  control operations in a single write to the control file. This is useful, for
       example, when planting many breakpoint instructions in the  process's  address  space,  or
       when stepping over a breakpointed instruction. Unlike pread(2) and pwrite(2), no provision
       is made for partial reads or writes; if the operation cannot be performed  completely,  it
       fails with EIO.

   PCNICE
       The  traced process's nice(2) value is incremented by the amount in the operand long. Only
       a process with the {PRIV_PROC_PRIOCNTL} privilege asserted in its effective set can better
       a  process's  priority in this way, but any user may lower the priority. This operation is
       not meaningful for all scheduling classes.

   PCSCRED
       Set the target process credentials to the values contained in the prcred_t structure oper-
       and  (see  /proc/pid/cred).  The  effective, real, and saved user-IDs and group-IDs of the
       target process are set. The target process's supplementary groups  are  not  changed;  the
       pr_ngroups and pr_groups members of the structure operand are ignored. Only the privileged
       processes can perform this operation; for all others it fails with EPERM.

   PCSCREDX
       Operates like PCSCRED but also sets the supplementary groups; the length of the data writ-
       ten with this control operation should be "sizeof (prcred_t) + sizeof (gid_t) * (#groups -
       1)".

   PCSPRIV
       Set the target process privilege to the values contained  in  the  prpriv_t  operand  (see
       /proc/pid/priv).  The  effective,  permitted, inheritable, and limit sets are all changed.
       Privilege flags can also be set. The process is made privilege aware unless it can  relin-
       quish privilege awareness. See privileges(5).

       The limit set of the target process cannot be grown. The other privilege sets must be sub-
       sets of the intersection of the effective set of the calling process with  the  new  limit
       set  of	the  target  process  or subsets of the original values of the sets in the target
       process.

       If any of the above restrictions are not met, EPERM is returned. If the structure  written
       is improperly formatted, EINVAL is returned.

PROGRAMMING NOTES
       For  security  reasons,	except	for  the  psinfo,  usage,  lpsinfo, lusage, lwpsinfo, and
       lwpusage files, which are world-readable, and except for privileged processes, an open  of
       a  /proc  file fails unless both the user-ID and group-ID of the caller match those of the
       traced process and the process's object file is readable by the caller. The effective  set
       of  the	caller	is a superset of both the inheritable and the permitted set of the target
       process. The limit set of the caller is a superset of the limit set of the target process.
       Except for the world-readable files just mentioned, files corresponding to setuid and set-
       gid processes can be opened only by the appropriately privileged process.

       A process that is missing the basic privilege {PRIV_PROC_INFO} cannot  see  any	processes
       under /proc that it cannot send a signal to.

       A  process  that has {PRIV_PROC_OWNER} asserted in its effective set can open any file for
       reading. To manipulate or control a process, the controlling process must have at least as
       many privileges in its effective set as the target process has in its effective, inherita-
       ble, and permitted sets. The limit set of the controlling process must be  a  superset  of
       the  limit  set of the target process. Additional restrictions apply if any of the uids of
       the target process are 0. See privileges(5).

       Even if held by a privileged process, an open process or lwp file descriptor  (other  than
       file  descriptors for the world-readable files) becomes invalid if the traced process per-
       forms an exec(2) of a setuid/setgid object file or an object file that the traced  process
       cannot read. Any operation performed on an invalid file descriptor, except close(2), fails
       with EAGAIN. In this situation, if any tracing flags are set and the process  or  any  lwp
       file  descriptor  is open for writing, the process will have been directed to stop and its
       run-on-last-close flag will have been set (see PCSET). This enables a controlling  process
       (if  it has permission) to reopen the /proc files to get new valid file descriptors, close
       the invalid file descriptors, unset the run-on-last-close flag (if desired), and  proceed.
       Just  closing  the  invalid file descriptors causes the traced process to resume execution
       with all tracing flags cleared. Any process not currently open for writing via /proc,  but
       that  has  left-over tracing flags from a previous open, and that executes a setuid/setgid
       or unreadable object file, will not be  stopped	but  will  have  all  its  tracing  flags
       cleared.

       To  wait  for  one  or more of a set of processes or lwps to stop or terminate, /proc file
       descriptors (other than those obtained by opening the cwd or root directories or by  open-
       ing  files  in  the  fd	or object directories) can be used in a poll(2) system call. When
       requested and returned, either of the polling events POLLPRI or POLLWRNORM indicates  that
       the process or lwp stopped on an event of interest. Although they cannot be requested, the
       polling events POLLHUP, POLLERR, and POLLNVAL may be returned. POLLHUP indicates that  the
       process	or  lwp  has  terminated.  POLLERR  indicates that the file descriptor has become
       invalid. POLLNVAL is returned immediately if POLLPRI or POLLWRNORM is requested on a  file
       descriptor  referring  to a system process (see PCSTOP). The requested events may be empty
       to wait simply for termination.

FILES
       /proc

	   directory (list of processes)

       /proc/pid

	   specific process directory

       /proc/self

	   alias for a process's own directory

       /proc/pid/as

	   address space file

       /proc/pid/ctl

	   process control file

       /proc/pid/status

	   process status

       /proc/pid/lstatus

	   array of lwp status structs

       /proc/pid/psinfo

	   process ps(1) info

       /proc/pid/lpsinfo

	   array of lwp ps(1) info structs

       /proc/pid/map

	   address space map

       /proc/pid/xmap

	   extended address space map

       /proc/pid/rmap

	   reserved address map

       /proc/pid/cred

	   process credentials

       /proc/pid/priv

	   process privileges

       /proc/pid/sigact

	   process signal actions

       /proc/pid/auxv

	   process aux vector

       /proc/pid/ldt

	   process LDT (x86 only)

       /proc/pid/usage

	   process usage

       /proc/pid/lusage

	   array of lwp usage structs

       /proc/pid/path

	   symbolic links to process open files

       /proc/pid/pagedata

	   process page data

       /proc/pid/watch

	   active watchpoints

       /proc/pid/cwd

	   alias for the current working directory

       /proc/pid/root

	   alias for the root directory

       /proc/pid/fd

	   directory (list of open files)

       /proc/pid/fd/*

	   aliases for process's open files

       /proc/pid/object

	   directory (list of mapped files)

       /proc/pid/object/a.out

	   alias for process's executable file

       /proc/pid/object/*

	   aliases for other mapped files

       /proc/pid/lwp

	   directory (list of lwps)

       /proc/pid/lwp/lwpid

	   specific lwp directory

       /proc/pid/lwp/agent

	   alias for the agent lwp directory

       /proc/pid/lwp/lwpid/lwpctl

	   lwp control file

       /proc/pid/lwp/lwpid/lwpstatus

	   lwp status

       /proc/pid/lwp/lwpid/lwpsinfo

	   lwp ps(1) info

       /proc/pid/lwp/lwpid/lwpusage

	   lwp usage

       /proc/pid/lwp/lwpid/gwindows

	   register windows (SPARC only)

       /proc/pid/lwp/lwpid/xregs

	   extra state registers

       /proc/pid/lwp/lwpid/asrs

	   ancillary state registers (SPARC V9 only)

SEE ALSO
       ls(1), ps(1), chroot(1M),  alarm(2),  brk(2),  chdir(2),  chroot(2),  close(2),	creat(2),
       dup(2),	 exec(2),  fcntl(2),  fork(2),	fork1(2),  fstat(2),  getdents(2),  getustack(2),
       kill(2), lseek(2), mmap(2), nice(2), open(2), poll(2),  pread(2),  ptrace(3C),  pwrite(2),
       read(2),   readlink(2),	 readv(2),  shmget(2),	sigaction(2),  sigaltstack(2),	vfork(2),
       write(2), writev(2), _stack_grow(3C), readdir(3C),  pthread_create(3C),	pthread_join(3C),
       siginfo.h(3HEAD),  signal.h(3HEAD),  thr_create(3C), thr_join(3C), types32.h(3HEAD), ucon-
       text.h(3HEAD), wait(3C), contract(4), process(4), lfcompile(5), privileges(5)

DIAGNOSTICS
       Errors that can occur in addition to the  errors  normally  associated  with  file  system
       access:

       E2BIG	    Data  to  be  returned in a read(2) of the page data file exceeds the size of
		    the read buffer provided by the caller.

       EACCES	    An attempt was made to examine a process that ran under a different uid  than
		    the  controlling process and {PRIV_PROC_OWNER} was not asserted in the effec-
		    tive set.

       EAGAIN	    The traced process has performed an exec(2) of a setuid/setgid object file or
		    of	an object file that it cannot read; all further operations on the process
		    or lwp file descriptor (except close(2)) elicit this error.

       EBUSY	    PCSTOP, PCDSTOP, PCWSTOP, or PCTWSTOP was applied to  a  system  process;  an
		    exclusive  open(2)	was  attempted on a /proc file for a process already open
		    for writing; PCRUN, PCSREG, PCSVADDR, PCSFPREG, or PCSXREG was applied  to	a
		    process  or  lwp  not stopped on an event of interest; an attempt was made to
		    mount /proc when it was already mounted; PCAGENT was  applied  to  a  process
		    that was not fully stopped or that already had an agent lwp.

       EINVAL	    In	general,  this	means that some invalid argument was supplied to a system
		    call. A non-exhaustive list of conditions eliciting this  error  includes:	a
		    control  message  operation  code is undefined; an out-of-range signal number
		    was specified with PCSSIG, PCKILL, or PCUNKILL; SIGKILL  was  specified  with
		    PCUNKILL;  PCSFPREG  was  applied on a system that does not support floating-
		    point operations; PCSXREG was applied on a system that does not support extra
		    state registers.

       EINTR	    A signal was received by the controlling process while waiting for the traced
		    process or lwp to stop via PCSTOP, PCWSTOP, or PCTWSTOP.

       EIO	    A write(2) was attempted at an illegal address in the traced process.

       ENOENT	    The traced process or lwp has terminated after being opened. The basic privi-
		    lege  {PRIV_PROC_INFO}  is	not  asserted in the effective set of the calling
		    process and the calling process cannot send a signal to the target process.

       ENOMEM	    The system-imposed limit on the number of  page  data  file  descriptors  was
		    reached on an open of /proc/pid/pagedata; an attempt was made with PCWATCH to
		    establish more watched areas than the system can support; the PCAGENT  opera-
		    tion was issued when the system was out of resources for creating lwps.

       ENOSYS	    An	attempt  was  made to perform an unsupported operation (such as creat(2),
		    link(2), or unlink(2)) on an entry in /proc.

       EOVERFLOW    A 32-bit controlling process attempted to  read  or  write	the  as  file  or
		    attempted to read the map, rmap, or pagedata file of a 64-bit target process.
		    A 32-bit controlling process attempted to apply one of the control operations
		    PCSREG, PCSXREG, PCSVADDR, PCWATCH, PCAGENT, PCREAD, PCWRITE to a 64-bit tar-
		    get process.

       EPERM	    The process that issued the PCSCRED or PCSCREDX operation did  not	have  the
		    {PRIV_PROC_SETID}  privilege  asserted  in	its effective set, or the process
		    that issued the PCNICE operation did not have the {PRIV_PROC_PRIOCNTL} in its
		    effective set.

		    An	attempt  was made to control a process of which the E, P, and I privilege
		    sets were not a subset of the effective set of the controlling process or the
		    limit  set	of  the controlling process is not a superset of limit set of the
		    controlled process.

		    Any of the uids of the target process are 0 or an attempt was made to  change
		    any of the uids to 0 using PCSCRED and the security policy imposed additional
		    restrictions. See privileges(5).

NOTES
       Descriptions of structures in this document include only interesting  structure	elements,
       not filler and padding fields, and may show elements out of order for descriptive clarity.
       The actual structure definitions are contained in <procfs.h>.

BUGS
       Because the old ioctl(2)-based version of /proc is currently supported for binary compati-
       bility  with  old  applications,  the top-level directory for a process, /proc/pid, is not
       world-readable, but it is world-searchable. Thus, anyone can  open  /proc/pid/psinfo  even
       though  ls(1)  applied to /proc/pid will fail for anyone but the owner or an appropriately
       privileged process. Support for the old ioctl(2)-based version of /proc will be dropped in
       a  future release, at which time the top-level directory for a process will be made world-
       readable.

       On SPARC based machines, the types gregset_t and fpregset_t defined in <sys/regset.h>  are
       similar	to  but  not  the  same  as  the  types  prgregset_t  and prfpregset_t defined in
       <procfs.h>.

SunOS 5.11				   29 Nov 2006					  proc(4)
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