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/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
*
* Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
*/
#include "libbb.h"
/*
In Linux we have three ways to determine "process name":
1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field.
2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall.
3. /proc/PID/exe symlink. Points to the running executable file.
kernel threads:
comm: thread name
cmdline: empty
exe: <readlink fails>
executable
comm: first 15 chars of base name
(if executable is a symlink, then first 15 chars of symlink name are used)
cmdline: argv[0] from exec syscall
exe: points to executable (resolves symlink, unlike comm)
script (an executable with #!/path/to/interpreter):
comm: first 15 chars of script's base name (symlinks are not resolved)
cmdline: /path/to/interpreter (symlinks are not resolved)
(script name is in argv[1], args are pushed into argv[2] etc)
exe: points to interpreter's executable (symlinks are resolved)
If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y),
some commands started from busybox shell, xargs or find are started by
execXXX("/proc/self/exe", applet_name, params....)
and therefore comm field contains "exe".
*/
static int comm_match(procps_status_t *p, const char *procName)
{
int argv1idx;
/* comm does not match */
if (strncmp(p->comm, procName, 15) != 0)
return 0;
/* in Linux, if comm is 15 chars, it may be a truncated */
if (p->comm[14] == '\0') /* comm is not truncated - match */
return 1;
/* comm is truncated, but first 15 chars match.
* This can be crazily_long_script_name.sh!
* The telltale sign is basename(argv[1]) == procName. */
if (!p->argv0)
return 0;
argv1idx = strlen(p->argv0) + 1;
if (argv1idx >= p->argv_len)
return 0;
if (strcmp(bb_basename(p->argv0 + argv1idx), procName) != 0)
return 0;
return 1;
}
/* find_pid_by_name()
*
* Modified by Vladimir Oleynik for use with libbb/procps.c
* This finds the pid of the specified process.
* Currently, it's implemented by rummaging through
* the proc filesystem.
*
* Returns a list of all matching PIDs
* It is the caller's duty to free the returned pidlist.
*/
pid_t* FAST_FUNC find_pid_by_name(const char *procName)
{
pid_t* pidList;
int i = 0;
procps_status_t* p = NULL;
pidList = xzalloc(sizeof(*pidList));
while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN))) {
if (comm_match(p, procName)
/* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/
|| (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0)
/* TOOD: we can also try /proc/NUM/exe link, do we want that? */
) {
pidList = xrealloc_vector(pidList, 2, i);
pidList[i++] = p->pid;
}
}
pidList[i] = 0;
return pidList;
}
pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList)
{
int i = 0;
while (pidList[i])
i++;
if (--i >= 0) {
pid_t k;
int j;
for (j = 0; i > j; i--, j++) {
k = pidList[i];
pidList[i] = pidList[j];
pidList[j] = k;
}
}
return pidList;
}
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