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 GPLv2 or later, see file LICENSE in this source tree. 8 */ 9#include "libbb.h" 10 11/* 12In Linux we have three ways to determine "process name": 131. /proc/PID/stat has "...(name)...", among other things. It's so-called "comm" field. 142. /proc/PID/cmdline's first NUL-terminated string. It's argv[0] from exec syscall. 153. /proc/PID/exe symlink. Points to the running executable file. 16 17kernel threads: 18 comm: thread name 19 cmdline: empty 20 exe: <readlink fails> 21 22executable 23 comm: first 15 chars of base name 24 (if executable is a symlink, then first 15 chars of symlink name are used) 25 cmdline: argv[0] from exec syscall 26 exe: points to executable (resolves symlink, unlike comm) 27 28script (an executable with #!/path/to/interpreter): 29 comm: first 15 chars of script's base name (symlinks are not resolved) 30 cmdline: /path/to/interpreter (symlinks are not resolved) 31 (script name is in argv[1], args are pushed into argv[2] etc) 32 exe: points to interpreter's executable (symlinks are resolved) 33 34If FEATURE_PREFER_APPLETS=y (and more so if FEATURE_SH_STANDALONE=y), 35some commands started from busybox shell, xargs or find are started by 36execXXX("/proc/self/exe", applet_name, params....) 37and therefore comm field contains "exe". 38*/ 39 40static int comm_match(procps_status_t *p, const char *procName) 41{ 42 int argv1idx; 43 const char *argv1; 44 45 if (strncmp(p->comm, procName, 15) != 0) 46 return 0; /* comm does not match */ 47 48 /* In Linux, if comm is 15 chars, it is truncated. 49 * (or maybe the name was exactly 15 chars, but there is 50 * no way to know that) */ 51 if (p->comm[14] == '\0') 52 return 1; /* comm is not truncated - matches */ 53 54 /* comm is truncated, but first 15 chars match. 55 * This can be crazily_long_script_name.sh! 56 * The telltale sign is basename(argv[1]) == procName */ 57 58 if (!p->argv0) 59 return 0; 60 61 argv1idx = strlen(p->argv0) + 1; 62 if (argv1idx >= p->argv_len) 63 return 0; 64 argv1 = p->argv0 + argv1idx; 65 66 if (strcmp(bb_basename(argv1), procName) != 0) 67 return 0; 68 69 return 1; 70} 71 72/* This finds the pid of the specified process. 73 * Currently, it's implemented by rummaging through 74 * the proc filesystem. 75 * 76 * Returns a list of all matching PIDs 77 * It is the caller's duty to free the returned pidlist. 78 * 79 * Modified by Vladimir Oleynik for use with libbb/procps.c 80 */ 81pid_t* FAST_FUNC find_pid_by_name(const char *procName) 82{ 83 pid_t* pidList; 84 int i = 0; 85 procps_status_t* p = NULL; 86 87 pidList = xzalloc(sizeof(*pidList)); 88 while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_COMM|PSSCAN_ARGVN|PSSCAN_EXE))) { 89 if (comm_match(p, procName) 90 /* or we require argv0 to match (essential for matching reexeced /proc/self/exe)*/ 91 || (p->argv0 && strcmp(bb_basename(p->argv0), procName) == 0) 92 /* or we require /proc/PID/exe link to match */ 93 || (p->exe && strcmp( 94 procName[0] == '/' ? p->exe /* support "pidof /path/to/binary" case too */ 95 : bb_basename(p->exe), 96 procName 97 ) == 0) 98 ) { 99 pidList = xrealloc_vector(pidList, 2, i); 100 pidList[i++] = p->pid; 101 } 102 } 103 104 pidList[i] = 0; 105 return pidList; 106} 107 108pid_t* FAST_FUNC pidlist_reverse(pid_t *pidList) 109{ 110 int i = 0; 111 while (pidList[i]) 112 i++; 113 if (--i >= 0) { 114 pid_t k; 115 int j; 116 for (j = 0; i > j; i--, j++) { 117 k = pidList[i]; 118 pidList[i] = pidList[j]; 119 pidList[j] = k; 120 } 121 } 122 return pidList; 123} 124