procps/kill.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini kill/killall[5] implementation for busybox
   4  *
   5  * Copyright (C) 1995, 1996 by Bruce Perens <bruce@pixar.com>.
   6  * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
   7  *
   8  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   9  */
  10 //config:config KILL
  11 //config:       bool "kill"
  12 //config:       default y
  13 //config:       help
  14 //config:         The command kill sends the specified signal to the specified
  15 //config:         process or process group. If no signal is specified, the TERM
  16 //config:         signal is sent.
  17 //config:
  18 //config:config KILLALL
  19 //config:       bool "killall"
  20 //config:       default y
  21 //config:       help
  22 //config:         killall sends a signal to all processes running any of the
  23 //config:         specified commands. If no signal name is specified, SIGTERM is
  24 //config:         sent.
  25 //config:
  26 //config:config KILLALL5
  27 //config:       bool "killall5"
  28 //config:       default y
  29 //config:       help
  30 //config:         The SystemV killall command. killall5 sends a signal
  31 //config:         to all processes except kernel threads and the processes
  32 //config:         in its own session, so it won't kill the shell that is running
  33 //config:         the script it was called from.
  34
  35 //applet:IF_KILL(APPLET(kill, BB_DIR_BIN, BB_SUID_DROP))
  36 //applet:IF_KILLALL(APPLET_ODDNAME(killall, kill, BB_DIR_USR_BIN, BB_SUID_DROP, killall))
  37 //applet:IF_KILLALL5(APPLET_ODDNAME(killall5, kill, BB_DIR_USR_SBIN, BB_SUID_DROP, killall5))
  38
  39 //kbuild:lib-$(CONFIG_KILL) += kill.o
  40 //kbuild:lib-$(CONFIG_KILLALL) += kill.o
  41 //kbuild:lib-$(CONFIG_KILLALL5) += kill.o
  42
  43 //usage:#define kill_trivial_usage
  44 //usage:       "[-l] [-SIG] PID..."
  45 //usage:#define kill_full_usage "\n\n"
  46 //usage:       "Send a signal (default: TERM) to given PIDs\n"
  47 //usage:     "\n        -l      List all signal names and numbers"
  48 /* //usage:  "\n        -s SIG  Yet another way of specifying SIG" */
  49 //usage:
  50 //usage:#define kill_example_usage
  51 //usage:       "$ ps | grep apache\n"
  52 //usage:       "252 root     root     S [apache]\n"
  53 //usage:       "263 www-data www-data S [apache]\n"
  54 //usage:       "264 www-data www-data S [apache]\n"
  55 //usage:       "265 www-data www-data S [apache]\n"
  56 //usage:       "266 www-data www-data S [apache]\n"
  57 //usage:       "267 www-data www-data S [apache]\n"
  58 //usage:       "$ kill 252\n"
  59 //usage:
  60 //usage:#define killall_trivial_usage
  61 //usage:       "[-l] [-q] [-SIG] PROCESS_NAME..."
  62 //usage:#define killall_full_usage "\n\n"
  63 //usage:       "Send a signal (default: TERM) to given processes\n"
  64 //usage:     "\n        -l      List all signal names and numbers"
  65 /* //usage:  "\n        -s SIG  Yet another way of specifying SIG" */
  66 //usage:     "\n        -q      Don't complain if no processes were killed"
  67 //usage:
  68 //usage:#define killall_example_usage
  69 //usage:       "$ killall apache\n"
  70 //usage:
  71 //usage:#define killall5_trivial_usage
  72 //usage:       "[-l] [-SIG] [-o PID]..."
  73 //usage:#define killall5_full_usage "\n\n"
  74 //usage:       "Send a signal (default: TERM) to all processes outside current session\n"
  75 //usage:     "\n        -l      List all signal names and numbers"
  76 //usage:     "\n        -o PID  Don't signal this PID"
  77 /* //usage:  "\n        -s SIG  Yet another way of specifying SIG" */
  78
  79 #include "libbb.h"
  80
  81 /* Note: kill_main is directly called from shell in order to implement
  82  * kill built-in. Shell substitutes job ids with process groups first.
  83  *
  84  * This brings some complications:
  85  *
  86  * + we can't use xfunc here
  87  * + we can't use applet_name
  88  * + we can't use bb_show_usage
  89  * (Above doesn't apply for killall[5] cases)
  90  *
  91  * kill %n gets translated into kill ' -<process group>' by shell (note space!)
  92  * This is needed to avoid collision with kill -9 ... syntax
  93  */
  94
  95 //kbuild:lib-$(CONFIG_ASH_JOB_CONTROL) += kill.o
  96 //kbuild:lib-$(CONFIG_HUSH_KILL) += kill.o
  97
  98 #define SH_KILL (ENABLE_ASH_JOB_CONTROL || ENABLE_HUSH_KILL)
  99 /* If shells want to have "kill", for ifdefs it's like ENABLE_KILL=1 */
 100 #if SH_KILL
 101 # undef  ENABLE_KILL
 102 # define ENABLE_KILL 1
 103 #endif
 104 #define KILL_APPLET_CNT (ENABLE_KILL + ENABLE_KILLALL + ENABLE_KILLALL5)
 105
 106 int kill_main(int argc UNUSED_PARAM, char **argv)
 107 {
 108         char *arg;
 109         pid_t pid;
 110         int signo = SIGTERM, errors = 0, quiet = 0;
 111
 112 #if KILL_APPLET_CNT == 1
 113 # define is_killall  ENABLE_KILLALL
 114 # define is_killall5 ENABLE_KILLALL5
 115 #else
 116 /* How to determine who we are? find 3rd char from the end:
 117  * kill, killall, killall5
 118  *  ^i       ^a        ^l  - it's unique
 119  * (checking from the start is complicated by /bin/kill... case) */
 120         const char char3 = argv[0][strlen(argv[0]) - 3];
 121 # define is_killall  (ENABLE_KILLALL  && char3 == 'a')
 122 # define is_killall5 (ENABLE_KILLALL5 && char3 == 'l')
 123 #endif
 124
 125         /* Parse any options */
 126         arg = *++argv;
 127
 128         if (!arg || arg[0] != '-') {
 129                 goto do_it_now;
 130         }
 131
 132         /* The -l option, which prints out signal names.
 133          * Intended usage in shell:
 134          * echo "Died of SIG`kill -l $?`"
 135          * We try to mimic what kill from coreutils-6.8 does */
 136         if (arg[1] == 'l' && arg[2] == '\0') {
 137                 arg = *++argv;
 138                 if (!arg) {
 139                         /* Print the whole signal list */
 140                         print_signames();
 141                         return 0;
 142                 }
 143                 /* -l <sig list> */
 144                 do {
 145                         if (isdigit(arg[0])) {
 146                                 signo = bb_strtou(arg, NULL, 10);
 147                                 if (errno) {
 148                                         bb_error_msg("unknown signal '%s'", arg);
 149                                         return EXIT_FAILURE;
 150                                 }
 151                                 /* Exitcodes >= 0x80 are to be treated
 152                                  * as "killed by signal (exitcode & 0x7f)" */
 153                                 puts(get_signame(signo & 0x7f));
 154                                 /* TODO: 'bad' signal# - coreutils says:
 155                                  * kill: 127: invalid signal
 156                                  * we just print "127" instead */
 157                         } else {
 158                                 signo = get_signum(arg);
 159                                 if (signo < 0) {
 160                                         bb_error_msg("unknown signal '%s'", arg);
 161                                         return EXIT_FAILURE;
 162                                 }
 163                                 printf("%d\n", signo);
 164                         }
 165                         arg = *++argv;
 166                 } while (arg);
 167                 return EXIT_SUCCESS;
 168         }
 169
 170         /* The -q quiet option */
 171         if (is_killall && arg[1] == 'q' && arg[2] == '\0') {
 172                 quiet = 1;
 173                 arg = *++argv;
 174                 if (!arg)
 175                         bb_show_usage();
 176                 if (arg[0] != '-')
 177                         goto do_it_now;
 178         }
 179
 180         arg++; /* skip '-' */
 181
 182         /* -o PID? (if present, it always is at the end of command line) */
 183         if (is_killall5 && arg[0] == 'o')
 184                 goto do_it_now;
 185
 186         if (argv[1] && arg[0] == 's' && arg[1] == '\0') { /* -s SIG? */
 187                 arg = *++argv;
 188         } /* else it must be -SIG */
 189         signo = get_signum(arg);
 190         if (signo < 0) { /* || signo > MAX_SIGNUM ? */
 191                 bb_error_msg("bad signal name '%s'", arg);
 192                 return EXIT_FAILURE;
 193         }
 194         arg = *++argv;
 195
 196  do_it_now:
 197         pid = getpid();
 198
 199         if (is_killall5) {
 200                 pid_t sid;
 201                 procps_status_t* p = NULL;
 202                 /* compat: exitcode 2 is "no one was signaled" */
 203                 int ret = 2;
 204
 205                 /* Find out our session id */
 206                 sid = getsid(pid);
 207                 /* Stop all processes */
 208                 if (signo != SIGSTOP && signo != SIGCONT)
 209                         kill(-1, SIGSTOP);
 210                 /* Signal all processes except those in our session */
 211                 while ((p = procps_scan(p, PSSCAN_PID|PSSCAN_SID)) != NULL) {
 212                         char **args;
 213
 214                         if (p->sid == (unsigned)sid
 215                          || p->sid == 0 /* compat: kernel thread, don't signal it */
 216                          || p->pid == (unsigned)pid
 217                          || p->pid == 1
 218                         ) {
 219                                 continue;
 220                         }
 221
 222                         /* All remaining args must be -o PID options.
 223                          * Check p->pid against them. */
 224                         args = argv;
 225                         while (*args) {
 226                                 pid_t omit;
 227
 228                                 arg = *args++;
 229                                 if (arg[0] != '-' || arg[1] != 'o') {
 230                                         bb_error_msg("bad option '%s'", arg);
 231                                         ret = 1;
 232                                         goto resume;
 233                                 }
 234                                 arg += 2;
 235                                 if (!arg[0] && *args)
 236                                         arg = *args++;
 237                                 omit = bb_strtoi(arg, NULL, 10);
 238                                 if (errno) {
 239                                         bb_error_msg("invalid number '%s'", arg);
 240                                         ret = 1;
 241                                         goto resume;
 242                                 }
 243                                 if (p->pid == omit)
 244                                         goto dont_kill;
 245                         }
 246                         kill(p->pid, signo);
 247                         ret = 0;
 248  dont_kill: ;
 249                 }
 250  resume:
 251                 /* And let them continue */
 252                 if (signo != SIGSTOP && signo != SIGCONT)
 253                         kill(-1, SIGCONT);
 254                 return ret;
 255         }
 256
 257 #if ENABLE_KILL || ENABLE_KILLALL
 258         /* Pid or name is required for kill/killall */
 259         if (!arg) {
 260                 bb_error_msg("you need to specify whom to kill");
 261                 return EXIT_FAILURE;
 262         }
 263
 264         if (!ENABLE_KILL || is_killall) {
 265                 /* Looks like they want to do a killall.  Do that */
 266                 do {
 267                         pid_t* pidList;
 268
 269                         pidList = find_pid_by_name(arg);
 270                         if (*pidList == 0) {
 271                                 errors++;
 272                                 if (!quiet)
 273                                         bb_error_msg("%s: no process killed", arg);
 274                         } else {
 275                                 pid_t *pl;
 276
 277                                 for (pl = pidList; *pl; pl++) {
 278                                         if (*pl == pid)
 279                                                 continue;
 280                                         if (kill(*pl, signo) == 0)
 281                                                 continue;
 282                                         errors++;
 283                                         if (!quiet)
 284                                                 bb_perror_msg("can't kill pid %d", (int)*pl);
 285                                 }
 286                         }
 287                         free(pidList);
 288                         arg = *++argv;
 289                 } while (arg);
 290                 return errors;
 291         }
 292 #endif
 293
 294 #if ENABLE_KILL
 295         /* Looks like they want to do a kill. Do that */
 296         while (arg) {
 297 # if SH_KILL
 298                 /*
 299                  * We need to support shell's "hack formats" of
 300                  * " -PRGP_ID" (yes, with a leading space)
 301                  * and " PID1 PID2 PID3" (with degenerate case "")
 302                  */
 303                 while (*arg != '\0') {
 304                         char *end;
 305                         if (*arg == ' ')
 306                                 arg++;
 307                         pid = bb_strtoi(arg, &end, 10);
 308                         if (errno && (errno != EINVAL || *end != ' ')) {
 309                                 bb_error_msg("invalid number '%s'", arg);
 310                                 errors++;
 311                                 break;
 312                         }
 313                         if (kill(pid, signo) != 0) {
 314                                 bb_perror_msg("can't kill pid %d", (int)pid);
 315                                 errors++;
 316                         }
 317                         arg = end; /* can only point to ' ' or '\0' now */
 318                 }
 319 # else /* ENABLE_KILL but !SH_KILL */
 320                 pid = bb_strtoi(arg, NULL, 10);
 321                 if (errno) {
 322                         bb_error_msg("invalid number '%s'", arg);
 323                         errors++;
 324                 } else if (kill(pid, signo) != 0) {
 325                         bb_perror_msg("can't kill pid %d", (int)pid);
 326                         errors++;
 327                 }
 328 # endif
 329                 arg = *++argv;
 330         }
 331         return errors;
 332 #endif
 333 }