Contents of /tags/mkinitrd-6_1_2/busybox/libbb/find_pid_by_name.c
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Mon May 4 17:23:09 2009 UTC (15 years, 4 months ago) by niro
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Mon May 4 17:23:09 2009 UTC (15 years, 4 months ago) by niro
File MIME type: text/plain
File size: 3174 byte(s)
tagged 'mkinitrd-6_1_2'
1 | /* 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 | /* |
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 | /* 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 | pid_t* FAST_FUNC find_pid_by_name(const char *procName) |
81 | { |
82 | pid_t* pidList; |
83 | int i = 0; |
84 | procps_status_t* p = NULL; |
85 | |
86 | 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 | pidList[i++] = p->pid; |
95 | } |
96 | } |
97 | |
98 | pidList[i] = 0; |
99 | return pidList; |
100 | } |
101 | |
102 | pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList) |
103 | { |
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 | } |