src/kill.c

   1 /* kill -- send a signal to a process
   2    Copyright (C) 2002-2023 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Paul Eggert.  */
  18
  19 #include <config.h>
  20 #include <stdckdint.h>
  21 #include <stdio.h>
  22 #include <getopt.h>
  23 #include <sys/types.h>
  24 #include <signal.h>
  25
  26 #include "system.h"
  27 #include "sig2str.h"
  28 #include "operand2sig.h"
  29 #include "quote.h"
  30
  31 /* The official name of this program (e.g., no 'g' prefix).  */
  32 #define PROGRAM_NAME "kill"
  33
  34 #define AUTHORS proper_name ("Paul Eggert")
  35
  36 #if ! (HAVE_DECL_STRSIGNAL || defined strsignal)
  37 # if ! (HAVE_DECL_SYS_SIGLIST || defined sys_siglist)
  38 #  if HAVE_DECL__SYS_SIGLIST || defined _sys_siglist
  39 #   define sys_siglist _sys_siglist
  40 #  elif HAVE_DECL___SYS_SIGLIST || defined __sys_siglist
  41 #   define sys_siglist __sys_siglist
  42 #  endif
  43 # endif
  44 # if HAVE_DECL_SYS_SIGLIST || defined sys_siglist
  45 #  define strsignal(signum) (0 <= (signum) && (signum) <= SIGNUM_BOUND \
  46                              ? sys_siglist[signum] \
  47                              : 0)
  48 # endif
  49 # ifndef strsignal
  50 #  define strsignal(signum) 0
  51 # endif
  52 #endif
  53
  54 static char const short_options[] =
  55   "0::1::2::3::4::5::6::7::8::9::"
  56   "A::B::C::D::E::F::G::H::I::J::K::M::"
  57   "N::O::P::Q::R::S::T::U::V::W::X::Y::Z::"
  58   "Lln:s:t";
  59
  60 static struct option const long_options[] =
  61 {
  62   {"list", no_argument, nullptr, 'l'},
  63   {"signal", required_argument, nullptr, 's'},
  64   {"table", no_argument, nullptr, 't'},
  65   {GETOPT_HELP_OPTION_DECL},
  66   {GETOPT_VERSION_OPTION_DECL},
  67   {nullptr, 0, nullptr, 0}
  68 };
  69
  70 void
  71 usage (int status)
  72 {
  73   if (status != EXIT_SUCCESS)
  74     emit_try_help ();
  75   else
  76     {
  77       printf (_("\
  78 Usage: %s [-s SIGNAL | -SIGNAL] PID...\n\
  79   or:  %s -l [SIGNAL]...\n\
  80   or:  %s -t [SIGNAL]...\n\
  81 "),
  82               program_name, program_name, program_name);
  83       fputs (_("\
  84 Send signals to processes, or list signals.\n\
  85 "), stdout);
  86
  87       emit_mandatory_arg_note ();
  88
  89       fputs (_("\
  90   -s, --signal=SIGNAL, -SIGNAL\n\
  91                    specify the name or number of the signal to be sent\n\
  92   -l, --list       list signal names, or convert signal names to/from numbers\n\
  93   -t, --table      print a table of signal information\n\
  94 "), stdout);
  95       fputs (HELP_OPTION_DESCRIPTION, stdout);
  96       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  97       fputs (_("\n\
  98 SIGNAL may be a signal name like 'HUP', or a signal number like '1',\n\
  99 or the exit status of a process terminated by a signal.\n\
 100 PID is an integer; if negative it identifies a process group.\n\
 101 "), stdout);
 102       printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
 103       emit_ancillary_info (PROGRAM_NAME);
 104     }
 105   exit (status);
 106 }
 107
 108 /* Print a row of 'kill -t' output.  NUM_WIDTH is the maximum signal
 109    number width, and SIGNUM is the signal number to print.  The
 110    maximum name width is NAME_WIDTH, and SIGNAME is the name to print.  */
 111
 112 static void
 113 print_table_row (int num_width, int signum,
 114                  int name_width, char const *signame)
 115 {
 116   char const *description = strsignal (signum);
 117   printf ("%*d %-*s %s\n", num_width, signum, name_width, signame,
 118           description ? description : "?");
 119 }
 120
 121 /* Print a list of signal names.  If TABLE, print a table.
 122    Print the names specified by ARGV if nonzero; otherwise,
 123    print all known names.  Return a suitable exit status.  */
 124
 125 static int
 126 list_signals (bool table, char *const *argv)
 127 {
 128   int signum;
 129   int status = EXIT_SUCCESS;
 130   char signame[SIG2STR_MAX];
 131
 132   if (table)
 133     {
 134       unsigned int name_width = 0;
 135
 136       /* Compute the maximum width of a signal number.  */
 137       unsigned int num_width = 1;
 138       for (signum = 1; signum <= SIGNUM_BOUND / 10; signum *= 10)
 139         num_width++;
 140
 141       /* Compute the maximum width of a signal name.  */
 142       for (signum = 1; signum <= SIGNUM_BOUND; signum++)
 143         if (sig2str (signum, signame) == 0)
 144           {
 145             size_t len = strlen (signame);
 146             if (name_width < len)
 147               name_width = len;
 148           }
 149
 150       if (argv)
 151         for (; *argv; argv++)
 152           {
 153             signum = operand2sig (*argv, signame);
 154             if (signum < 0)
 155               status = EXIT_FAILURE;
 156             else
 157               print_table_row (num_width, signum, name_width, signame);
 158           }
 159       else
 160         for (signum = 1; signum <= SIGNUM_BOUND; signum++)
 161           if (sig2str (signum, signame) == 0)
 162             print_table_row (num_width, signum, name_width, signame);
 163     }
 164   else
 165     {
 166       if (argv)
 167         for (; *argv; argv++)
 168           {
 169             signum = operand2sig (*argv, signame);
 170             if (signum < 0)
 171               status = EXIT_FAILURE;
 172             else
 173               {
 174                 if (ISDIGIT (**argv))
 175                   puts (signame);
 176                 else
 177                   printf ("%d\n", signum);
 178               }
 179           }
 180       else
 181         for (signum = 1; signum <= SIGNUM_BOUND; signum++)
 182           if (sig2str (signum, signame) == 0)
 183             puts (signame);
 184     }
 185
 186   return status;
 187 }
 188
 189 /* Send signal SIGNUM to all the processes or process groups specified
 190    by ARGV.  Return a suitable exit status.  */
 191
 192 static int
 193 send_signals (int signum, char *const *argv)
 194 {
 195   int status = EXIT_SUCCESS;
 196   char const *arg = *argv;
 197
 198   do
 199     {
 200       char *endp;
 201       intmax_t n = (errno = 0, strtoimax (arg, &endp, 10));
 202       pid_t pid;
 203
 204       if (errno == ERANGE || ckd_add (&pid, n, 0)
 205           || arg == endp || *endp)
 206         {
 207           error (0, 0, _("%s: invalid process id"), quote (arg));
 208           status = EXIT_FAILURE;
 209         }
 210       else if (kill (pid, signum) != 0)
 211         {
 212           error (0, errno, "%s", quote (arg));
 213           status = EXIT_FAILURE;
 214         }
 215     }
 216   while ((arg = *++argv));
 217
 218   return status;
 219 }
 220
 221 int
 222 main (int argc, char **argv)
 223 {
 224   int optc;
 225   bool list = false;
 226   bool table = false;
 227   int signum = -1;
 228   char signame[SIG2STR_MAX];
 229
 230   initialize_main (&argc, &argv);
 231   set_program_name (argv[0]);
 232   setlocale (LC_ALL, "");
 233   bindtextdomain (PACKAGE, LOCALEDIR);
 234   textdomain (PACKAGE);
 235
 236   atexit (close_stdout);
 237
 238   while ((optc = getopt_long (argc, argv, short_options, long_options, nullptr))
 239          != -1)
 240     switch (optc)
 241       {
 242       case '0': case '1': case '2': case '3': case '4':
 243       case '5': case '6': case '7': case '8': case '9':
 244         if (optind != 2)
 245           {
 246             /* This option is actually a process-id.  */
 247             optind--;
 248             goto no_more_options;
 249           }
 250         FALLTHROUGH;
 251       case 'A': case 'B': case 'C': case 'D': case 'E':
 252       case 'F': case 'G': case 'H': case 'I': case 'J':
 253       case 'K': /*case 'L':*/ case 'M': case 'N': case 'O':
 254       case 'P': case 'Q': case 'R': case 'S': case 'T':
 255       case 'U': case 'V': case 'W': case 'X': case 'Y':
 256       case 'Z':
 257         if (! optarg)
 258           optarg = argv[optind - 1] + strlen (argv[optind - 1]);
 259         if (optarg != argv[optind - 1] + 2)
 260           {
 261             error (0, 0, _("invalid option -- %c"), optc);
 262             usage (EXIT_FAILURE);
 263           }
 264         optarg--;
 265         FALLTHROUGH;
 266       case 'n': /* -n is not documented, but is for Bash compatibility.  */
 267       case 's':
 268         if (0 <= signum)
 269           {
 270             error (0, 0, _("%s: multiple signals specified"), quote (optarg));
 271             usage (EXIT_FAILURE);
 272           }
 273         signum = operand2sig (optarg, signame);
 274         if (signum < 0)
 275           usage (EXIT_FAILURE);
 276         break;
 277
 278       case 'L': /* -L is not documented, but is for procps compatibility.  */
 279       case 't':
 280         table = true;
 281         FALLTHROUGH;
 282       case 'l':
 283         if (list)
 284           {
 285             error (0, 0, _("multiple -l or -t options specified"));
 286             usage (EXIT_FAILURE);
 287           }
 288         list = true;
 289         break;
 290
 291       case_GETOPT_HELP_CHAR;
 292       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 293       default:
 294         usage (EXIT_FAILURE);
 295       }
 296  no_more_options:
 297
 298   if (signum < 0)
 299     signum = SIGTERM;
 300   else if (list)
 301     {
 302       error (0, 0, _("cannot combine signal with -l or -t"));
 303       usage (EXIT_FAILURE);
 304     }
 305
 306   if ( ! list && argc <= optind)
 307     {
 308       error (0, 0, _("no process ID specified"));
 309       usage (EXIT_FAILURE);
 310     }
 311
 312   return (list
 313           ? list_signals (table, optind < argc ? argv + optind : nullptr)
 314           : send_signals (signum, argv + optind));
 315 }