[3320] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /*
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| 3 | * Utility routines.
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| 4 | *
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| 5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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| 6 | *
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| 7 | * Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 8 | */
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| 9 |
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| 10 | #include "libbb.h"
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| 11 |
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| 12 | /*
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| 13 | In Linux we have three ways to determine "process name":
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| 14 | 1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field.
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| 15 | 2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall.
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| 16 | 3. /proc/PID/exe symlink. Points to the running executable file.
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| 17 |
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| 18 | kernel threads:
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| 19 | comm: thread name
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| 20 | cmdline: empty
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| 21 | exe: <readlink fails>
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| 22 |
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| 23 | executable
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| 24 | comm: first 15 chars of base name
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| 25 | (if executable is a symlink, then first 15 chars of symlink name are used)
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| 26 | cmdline: argv[0] from exec syscall
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| 27 | exe: points to executable (resolves symlink, unlike comm)
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| 28 |
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| 29 | script (an executable with #!/path/to/interpreter):
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| 30 | comm: first 15 chars of script's base name (symlinks are not resolved)
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| 31 | cmdline: /path/to/interpreter (symlinks are not resolved)
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| 32 | (script name is in argv[1], args are pushed into argv[2] etc)
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| 33 | exe: points to interpreter's executable (symlinks are resolved)
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| 34 |
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| 35 | If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y),
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| 36 | some commands started from busybox shell, xargs or find are started by
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| 37 | execXXX("/proc/self/exe", applet_name, params....)
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| 38 | and therefore comm field contains "exe".
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| 39 | */
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| 40 |
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| 41 | static int comm_match(procps_status_t *p, const char *procName)
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| 42 | {
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| 43 | int argv1idx;
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| 44 | const char *argv1;
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| 45 |
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| 46 | if (strncmp(p->comm, procName, 15) != 0)
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| 47 | return 0; /* comm does not match */
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| 48 |
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| 49 | /* In Linux, if comm is 15 chars, it is truncated.
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| 50 | * (or maybe the name was exactly 15 chars, but there is
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| 51 | * no way to know that) */
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| 52 | if (p->comm[14] == '\0')
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| 53 | return 1; /* comm is not truncated - matches */
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| 54 |
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| 55 | /* comm is truncated, but first 15 chars match.
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| 56 | * This can be crazily_long_script_name.sh!
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| 57 | * The telltale sign is basename(argv[1]) == procName */
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| 58 |
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| 59 | if (!p->argv0)
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| 60 | return 0;
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| 61 |
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| 62 | argv1idx = strlen(p->argv0) + 1;
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| 63 | if (argv1idx >= p->argv_len)
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| 64 | return 0;
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| 65 | argv1 = p->argv0 + argv1idx;
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| 66 |
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| 67 | if (strcmp(bb_basename(argv1), procName) != 0)
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| 68 | return 0;
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| 69 |
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| 70 | return 1;
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| 71 | }
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| 72 |
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| 73 | /* This finds the pid of the specified process.
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| 74 | * Currently, it's implemented by rummaging through
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| 75 | * the proc filesystem.
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| 76 | *
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| 77 | * Returns a list of all matching PIDs
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| 78 | * It is the caller's duty to free the returned pidlist.
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| 79 | *
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| 80 | * Modified by Vladimir Oleynik for use with libbb/procps.c
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| 81 | */
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| 82 | pid_t* FAST_FUNC find_pid_by_name(const char *procName)
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| 83 | {
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| 84 | pid_t* pidList;
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| 85 | int i = 0;
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| 86 | procps_status_t* p = NULL;
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| 87 |
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| 88 | pidList = xzalloc(sizeof(*pidList));
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| 89 | while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN|PSSCAN_EXE))) {
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| 90 | if (comm_match(p, procName)
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| 91 | /* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/
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| 92 | || (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0)
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| 93 | /* or we require /proc/PID/exe link to match */
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| 94 | || (p->exe && strcmp(bb_basename(p->exe), procName) == 0)
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| 95 | ) {
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| 96 | pidList = xrealloc_vector(pidList, 2, i);
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| 97 | pidList[i++] = p->pid;
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| 98 | }
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| 99 | }
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| 100 |
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| 101 | pidList[i] = 0;
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| 102 | return pidList;
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| 103 | }
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| 104 |
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| 105 | pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList)
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| 106 | {
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| 107 | int i = 0;
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| 108 | while (pidList[i])
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| 109 | i++;
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| 110 | if (--i >= 0) {
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| 111 | pid_t k;
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| 112 | int j;
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| 113 | for (j = 0; i > j; i--, j++) {
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| 114 | k = pidList[i];
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| 115 | pidList[i] = pidList[j];
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| 116 | pidList[j] = k;
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| 117 | }
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| 118 | }
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| 119 | return pidList;
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| 120 | }
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