mirror of
https://github.com/topjohnwu/ndk-busybox.git
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120 lines
3.2 KiB
C
120 lines
3.2 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Utility routines.
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*
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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#include "libbb.h"
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/*
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In Linux we have three ways to determine "process name":
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1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field.
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2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall.
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3. /proc/PID/exe symlink. Points to the running executable file.
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kernel threads:
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comm: thread name
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cmdline: empty
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exe: <readlink fails>
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executable
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comm: first 15 chars of base name
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(if executable is a symlink, then first 15 chars of symlink name are used)
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cmdline: argv[0] from exec syscall
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exe: points to executable (resolves symlink, unlike comm)
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script (an executable with #!/path/to/interpreter):
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comm: first 15 chars of script's base name (symlinks are not resolved)
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cmdline: /path/to/interpreter (symlinks are not resolved)
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(script name is in argv[1], args are pushed into argv[2] etc)
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exe: points to interpreter's executable (symlinks are resolved)
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If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y),
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some commands started from busybox shell, xargs or find are started by
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execXXX("/proc/self/exe", applet_name, params....)
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and therefore comm field contains "exe".
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*/
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static int comm_match(procps_status_t *p, const char *procName)
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{
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int argv1idx;
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const char *argv1;
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if (strncmp(p->comm, procName, 15) != 0)
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return 0; /* comm does not match */
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/* In Linux, if comm is 15 chars, it is truncated.
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* (or maybe the name was exactly 15 chars, but there is
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* no way to know that) */
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if (p->comm[14] == '\0')
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return 1; /* comm is not truncated - matches */
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/* comm is truncated, but first 15 chars match.
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* This can be crazily_long_script_name.sh!
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* The telltale sign is basename(argv[1]) == procName */
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if (!p->argv0)
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return 0;
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argv1idx = strlen(p->argv0) + 1;
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if (argv1idx >= p->argv_len)
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return 0;
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argv1 = p->argv0 + argv1idx;
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if (strcmp(bb_basename(argv1), procName) != 0)
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return 0;
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return 1;
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}
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/* This finds the pid of the specified process.
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* Currently, it's implemented by rummaging through
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* the proc filesystem.
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*
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* Returns a list of all matching PIDs
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* It is the caller's duty to free the returned pidlist.
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*
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* Modified by Vladimir Oleynik for use with libbb/procps.c
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*/
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pid_t* FAST_FUNC find_pid_by_name(const char *procName)
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{
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pid_t* pidList;
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int i = 0;
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procps_status_t* p = NULL;
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pidList = xzalloc(sizeof(*pidList));
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while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN|PSSCAN_EXE))) {
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if (comm_match(p, procName)
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/* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/
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|| (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0)
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/* or we require /proc/PID/exe link to match */
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|| (p->exe && strcmp(bb_basename(p->exe), procName) == 0)
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) {
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pidList = xrealloc_vector(pidList, 2, i);
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pidList[i++] = p->pid;
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}
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}
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pidList[i] = 0;
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return pidList;
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}
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pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList)
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{
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int i = 0;
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while (pidList[i])
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i++;
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if (--i >= 0) {
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pid_t k;
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int j;
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for (j = 0; i > j; i--, j++) {
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k = pidList[i];
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pidList[i] = pidList[j];
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pidList[j] = k;
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}
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}
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return pidList;
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}
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