Annotation of /tags/mkinitrd-6_1_11/busybox/libbb/find_pid_by_name.c
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Revision 816 -
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Fri Apr 24 18:33:46 2009 UTC (15 years, 5 months ago) by niro
Original Path: trunk/mkinitrd-magellan/busybox/libbb/find_pid_by_name.c
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File size: 3174 byte(s)
Fri Apr 24 18:33:46 2009 UTC (15 years, 5 months ago) by niro
Original Path: trunk/mkinitrd-magellan/busybox/libbb/find_pid_by_name.c
File MIME type: text/plain
File size: 3174 byte(s)
-updated to busybox-1.13.4
1 | niro | 532 | /* vi: set sw=4 ts=4: */ |
2 | /* | ||
3 | * Utility routines. | ||
4 | * | ||
5 | * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org> | ||
6 | * | ||
7 | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. | ||
8 | */ | ||
9 | |||
10 | #include "libbb.h" | ||
11 | |||
12 | niro | 816 | /* |
13 | In Linux we have three ways to determine "process name": | ||
14 | 1. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field. | ||
15 | 2. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall. | ||
16 | 3. /proc/PID/exe symlink. Points to the running executable file. | ||
17 | |||
18 | kernel threads: | ||
19 | comm: thread name | ||
20 | cmdline: empty | ||
21 | exe: <readlink fails> | ||
22 | |||
23 | executable | ||
24 | comm: first 15 chars of base name | ||
25 | (if executable is a symlink, then first 15 chars of symlink name are used) | ||
26 | cmdline: argv[0] from exec syscall | ||
27 | exe: points to executable (resolves symlink, unlike comm) | ||
28 | |||
29 | script (an executable with #!/path/to/interpreter): | ||
30 | comm: first 15 chars of script's base name (symlinks are not resolved) | ||
31 | cmdline: /path/to/interpreter (symlinks are not resolved) | ||
32 | (script name is in argv[1], args are pushed into argv[2] etc) | ||
33 | exe: points to interpreter's executable (symlinks are resolved) | ||
34 | |||
35 | If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y), | ||
36 | some commands started from busybox shell, xargs or find are started by | ||
37 | execXXX("/proc/self/exe", applet_name, params....) | ||
38 | and therefore comm field contains "exe". | ||
39 | */ | ||
40 | |||
41 | static int comm_match(procps_status_t *p, const char *procName) | ||
42 | { | ||
43 | int argv1idx; | ||
44 | |||
45 | /* comm does not match */ | ||
46 | if (strncmp(p->comm, procName, 15) != 0) | ||
47 | return 0; | ||
48 | |||
49 | /* in Linux, if comm is 15 chars, it may be a truncated */ | ||
50 | if (p->comm[14] == '\0') /* comm is not truncated - match */ | ||
51 | return 1; | ||
52 | |||
53 | /* comm is truncated, but first 15 chars match. | ||
54 | * This can be crazily_long_script_name.sh! | ||
55 | * The telltale sign is basename(argv[1]) == procName. */ | ||
56 | |||
57 | if (!p->argv0) | ||
58 | return 0; | ||
59 | |||
60 | argv1idx = strlen(p->argv0) + 1; | ||
61 | if (argv1idx >= p->argv_len) | ||
62 | return 0; | ||
63 | |||
64 | if (strcmp(bb_basename(p->argv0 + argv1idx), procName) != 0) | ||
65 | return 0; | ||
66 | |||
67 | return 1; | ||
68 | } | ||
69 | |||
70 | niro | 532 | /* find_pid_by_name() |
71 | * | ||
72 | * Modified by Vladimir Oleynik for use with libbb/procps.c | ||
73 | * This finds the pid of the specified process. | ||
74 | * Currently, it's implemented by rummaging through | ||
75 | * the proc filesystem. | ||
76 | * | ||
77 | * Returns a list of all matching PIDs | ||
78 | * It is the caller's duty to free the returned pidlist. | ||
79 | */ | ||
80 | niro | 816 | pid_t* FAST_FUNC find_pid_by_name(const char *procName) |
81 | niro | 532 | { |
82 | pid_t* pidList; | ||
83 | int i = 0; | ||
84 | procps_status_t* p = NULL; | ||
85 | |||
86 | niro | 816 | pidList = xzalloc(sizeof(*pidList)); |
87 | while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN))) { | ||
88 | if (comm_match(p, procName) | ||
89 | /* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/ | ||
90 | || (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0) | ||
91 | /* TODO: we can also try /proc/NUM/exe link, do we want that? */ | ||
92 | ) { | ||
93 | pidList = xrealloc_vector(pidList, 2, i); | ||
94 | niro | 532 | pidList[i++] = p->pid; |
95 | } | ||
96 | } | ||
97 | |||
98 | pidList[i] = 0; | ||
99 | return pidList; | ||
100 | } | ||
101 | |||
102 | niro | 816 | pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList) |
103 | niro | 532 | { |
104 | int i = 0; | ||
105 | while (pidList[i]) | ||
106 | i++; | ||
107 | if (--i >= 0) { | ||
108 | pid_t k; | ||
109 | int j; | ||
110 | for (j = 0; i > j; i--, j++) { | ||
111 | k = pidList[i]; | ||
112 | pidList[i] = pidList[j]; | ||
113 | pidList[j] = k; | ||
114 | } | ||
115 | } | ||
116 | return pidList; | ||
117 | } |