kvm_getenvv(3) [freebsd man page]

KVM_GETPROCS(3) 					   BSD Library Functions Manual 					   KVM_GETPROCS(3)

NAME

     kvm_getprocs, kvm_getargv, kvm_getenvv -- access user process state

LIBRARY

     Kernel Data Access Library (libkvm, -lkvm)

SYNOPSIS

     #include <kvm.h>
     #include <sys/param.h>
     #include <sys/sysctl.h>
     #include <sys/user.h>

     struct kinfo_proc *
     kvm_getprocs(kvm_t *kd, int op, int arg, int *cnt);

     char **
     kvm_getargv(kvm_t *kd, const struct kinfo_proc *p, int nchr);

     char **
     kvm_getenvv(kvm_t *kd, const struct kinfo_proc *p, int nchr);

DESCRIPTION

     The kvm_getprocs() function returns a (sub-)set of active processes in the kernel indicated by kd.  The op and arg arguments constitute a
     predicate which limits the set of processes returned.  The value of op describes the filtering predicate as follows:

	   KERN_PROC_ALL	 all processes and kernel visible threads
	   KERN_PROC_PROC	 all processes, without threads
	   KERN_PROC_PID	 processes with process ID arg
	   KERN_PROC_PGRP	 processes with process group arg
	   KERN_PROC_SESSION	 processes with session arg
	   KERN_PROC_TTY	 processes with TTY arg
	   KERN_PROC_UID	 processes with effective user ID arg
	   KERN_PROC_RUID	 processes with real user ID arg
	   KERN_PROC_INC_THREAD  modifier to return all kernel visible threads when filtering by process ID, process group, TTY, user ID, and real
				 user ID

     The number of processes found is returned in the reference parameter cnt.	The processes are returned as a contiguous array of kinfo_proc
     structures.  This memory is locally allocated, and subsequent calls to kvm_getprocs() and kvm_close() will overwrite this storage.

     The kvm_getargv() function returns a null-terminated argument vector that corresponds to the command line arguments passed to process indi-
     cated by p.  Most likely, these arguments correspond to the values passed to exec(3) on process creation.	This information is, however,
     deliberately under control of the process itself.	Note that the original command name can be found, unaltered, in the p_comm field of the
     process structure returned by kvm_getprocs().

     The nchr argument indicates the maximum number of characters, including null bytes, to use in building the strings.  If this amount is
     exceeded, the string causing the overflow is truncated and the partial result is returned.  This is handy for programs like ps(1) and w(1)
     that print only a one line summary of a command and should not copy out large amounts of text only to ignore it.  If nchr is zero, no limit
     is imposed and all argument strings are returned in their entirety.

     The memory allocated to the argv pointers and string storage is owned by the kvm library.	Subsequent kvm_getprocs() and kvm_close(3) calls
     will clobber this storage.

     The kvm_getenvv() function is similar to kvm_getargv() but returns the vector of environment strings.  This data is also alterable by the
     process.

RETURN VALUES

     The kvm_getprocs(), kvm_getargv(), and kvm_getenvv() functions return NULL on failure.

SEE ALSO

     kvm(3), kvm_close(3), kvm_geterr(3), kvm_nlist(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3)

BUGS

     These routines do not belong in the kvm interface.

BSD
								 November 22, 2011							       BSD

Check Out this Related Man Page

KVM(3)							   BSD Library Functions Manual 						    KVM(3)

NAME

     kvm -- kernel memory interface

LIBRARY

     Kernel Data Access Library (libkvm, -lkvm)

DESCRIPTION

     The kvm library provides a uniform interface for accessing kernel virtual memory images, including live systems and crash dumps.  Access to
     live systems is via sysctl(3) for some functions, and mem(4) and kmem(4) for other functions, while crash dumps can be examined via the core
     file generated by savecore(8).  The interface behaves similarly in both cases.  Memory can be read and written, kernel symbol addresses can
     be looked up efficiently, and information about user processes can be gathered.

     The kvm_open() function is first called to obtain a descriptor for all subsequent calls.

COMPATIBILITY

     The kvm interface was first introduced in SunOS.  A considerable number of programs have been developed that use this interface, making back-
     ward compatibility highly desirable.  In most respects, the Sun kvm interface is consistent and clean.  Accordingly, the generic portion of
     the interface (i.e., kvm_open(), kvm_close(), kvm_read(), kvm_write(), and kvm_nlist()) has been incorporated into the BSD interface.
     Indeed, many kvm applications (i.e., debuggers and statistical monitors) use only this subset of the interface.

     The process interface was not kept.  This is not a portability issue since any code that manipulates processes is inherently machine depen-
     dent.

     Finally, the Sun kvm error reporting semantics are poorly defined.  The library can be configured either to print errors to stderr automati-
     cally, or to print no error messages at all.  In the latter case, the nature of the error cannot be determined.  To overcome this, the BSD
     interface includes a routine, kvm_geterr(3), to return (not print out) the error message corresponding to the most recent error condition on
     the given descriptor.

SEE ALSO

     kvm_close(3), kvm_getargv(3), kvm_getenvv(3), kvm_geterr(3), kvm_getfiles(3), kvm_getloadavg(3), kvm_getprocs(3), kvm_getswapinfo(3),
     kvm_nlist(3), kvm_open(3), kvm_openfiles(3), kvm_read(3), kvm_write(3), sysctl(3), kmem(4), mem(4)

BSD
								  April 25, 2010							       BSD

Linux and UNIX Man Pages

kvm_getenvv(3) [freebsd man page]

Check Out this Related Man Page