P_CANDEBUG(9) BSD Kernel Developer's Manual P_CANDEBUG(9)NAME
p_candebug -- determine debuggability of a process
SYNOPSIS
#include <sys/param.h>
#include <sys/proc.h>
int
p_candebug(struct thread *td, struct proc *p);
DESCRIPTION
This function can be used to determine if a given process p is debuggable by the thread td.
SYSCTL VARIABLES
The following sysctl(8) variables directly influence the behaviour of p_candebug():
kern.securelevel
Debugging of the init process is not allowed if this variable is 1 or greater.
security.bsd.unprivileged_proc_debug
Must be set to a non-zero value to allow unprivileged processes access to the kernel's debug facilities.
RETURN VALUES
The p_candebug() function returns 0 if the process denoted by p is debuggable by thread td, or a non-zero error return value otherwise.
ERRORS
[EACCESS] The MAC subsystem denied debuggability.
[EAGAIN] Process p is in the process of being exec()'ed.
[EPERM] Thread td lacks super-user credentials and process p is executing a set-user-ID or set-group-ID executable.
[EPERM] Thread td lacks super-user credentials and process p's group set is not a subset of td's effective group set.
[EPERM] Thread td lacks super-user credentials and process p's user IDs do not match thread td's effective user ID.
[EPERM] Process p denotes the initial process initproc() and the sysctl(8) variable kern.securelevel is greater than zero.
[ESRCH] Process p is not visible to thread td as determined by cr_seeotheruids(9) or cr_seeothergids(9).
[ESRCH] Thread td has been jailed and process p does not belong to the same jail as td.
[ESRCH] The MAC subsystem denied debuggability.
SEE ALSO jail(2), sysctl(8), cr_seeothergids(9), cr_seeotheruids(9), mac(9), p_cansee(9), prison_check(9)BSD November 19, 2006 BSD
Check Out this Related Man Page
KILL(2) BSD System Calls Manual KILL(2)NAME
kill -- send signal to a process
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/types.h>
#include <signal.h>
int
kill(pid_t pid, int sig);
DESCRIPTION
The kill() system call sends the signal given by sig to pid, a process or a group of processes. The sig argument may be one of the signals
specified in sigaction(2) or it may be 0, in which case error checking is performed but no signal is actually sent. This can be used to
check the validity of pid.
For a process to have permission to send a signal to a process designated by pid, the user must be the super-user, or the real or saved user
ID of the receiving process must match the real or effective user ID of the sending process. A single exception is the signal SIGCONT, which
may always be sent to any process with the same session ID as the sender. In addition, if the security.bsd.conservative_signals sysctl is
set to 1, the user is not a super-user, and the receiver is set-uid, then only job control and terminal control signals may be sent (in par-
ticular, only SIGKILL, SIGINT, SIGTERM, SIGALRM, SIGSTOP, SIGTTIN, SIGTTOU, SIGTSTP, SIGHUP, SIGUSR1, SIGUSR2).
If pid is greater than zero:
The sig signal is sent to the process whose ID is equal to pid.
If pid is zero:
The sig signal is sent to all processes whose group ID is equal to the process group ID of the sender, and for which the process has
permission; this is a variant of killpg(2).
If pid is -1:
If the user has super-user privileges, the signal is sent to all processes excluding system processes (with P_SYSTEM flag set),
process with ID 1 (usually init(8)), and the process sending the signal. If the user is not the super user, the signal is sent to
all processes with the same uid as the user excluding the process sending the signal. No error is returned if any process could be
signaled.
For compatibility with System V, if the process number is negative but not -1, the signal is sent to all processes whose process group ID is
equal to the absolute value of the process number. This is a variant of killpg(2).
RETURN VALUES
The kill() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate
the error.
ERRORS
The kill() system call will fail and no signal will be sent if:
[EINVAL] The sig argument is not a valid signal number.
[ESRCH] No process or process group can be found corresponding to that specified by pid.
[EPERM] The sending process does not have permission to send sig to the receiving process.
SEE ALSO getpgrp(2), getpid(2), killpg(2), sigaction(2), sigqueue(2), raise(3), init(8)STANDARDS
The kill() system call is expected to conform to ISO/IEC 9945-1:1990 (``POSIX.1'').
HISTORY
The kill() function appeared in Version 7 AT&T UNIX.
BSD March 15, 2012 BSD