src/coreutils.c

   1 /* Copyright (C) 2014-2023 Free Software Foundation, Inc.
   2
   3    This program is free software: you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation, either version 3 of the License, or
   6    (at your option) any later version.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  15
  16 /* coreutils.c aggregates the functionality of every other tool into a single
  17    binary multiplexed by the value of argv[0]. This is enabled by passing
  18    --enable-single-binary to configure.
  19
  20    Written by Alex Deymo <deymo@chromium.org>.  */
  21
  22 #include <config.h>
  23 #include <getopt.h>
  24 #include <stdio.h>
  25 #if HAVE_PRCTL
  26 # include <sys/prctl.h>
  27 #endif
  28
  29 #include "system.h"
  30 #include "quote.h"
  31
  32 #ifdef SINGLE_BINARY
  33 /* Declare the main function on each one of the selected tools.  This name
  34    needs to match the one passed as CFLAGS on single-binary.mk (generated
  35    by gen-single-binary.sh). */
  36 # define SINGLE_BINARY_PROGRAM(prog_name_str, main_name) \
  37   int single_binary_main_##main_name (int, char **);
  38 # include "coreutils.h"
  39 # undef SINGLE_BINARY_PROGRAM
  40 #endif
  41
  42 /* The official name of this program (e.g., no 'g' prefix).  */
  43 #define PROGRAM_NAME "coreutils"
  44
  45 #define AUTHORS \
  46   proper_name ("Alex Deymo")
  47
  48 static struct option const long_options[] =
  49 {
  50   {GETOPT_HELP_OPTION_DECL},
  51   {GETOPT_VERSION_OPTION_DECL},
  52   {nullptr, 0, nullptr, 0}
  53 };
  54
  55
  56 void
  57 usage (int status)
  58 {
  59   if (status != EXIT_SUCCESS)
  60     emit_try_help ();
  61   else
  62     {
  63       printf (_("\
  64 Usage: %s --coreutils-prog=PROGRAM_NAME [PARAMETERS]... \n"),
  65               program_name);
  66       fputs (_("\
  67 Execute the PROGRAM_NAME built-in program with the given PARAMETERS.\n\
  68 \n"), stdout);
  69       fputs (HELP_OPTION_DESCRIPTION, stdout);
  70       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  71
  72 #ifdef SINGLE_BINARY
  73 /* XXX: Ideally we'd like to present "install" here, not "ginstall".  */
  74       char const *prog_name_list =
  75 # define SINGLE_BINARY_PROGRAM(prog_name_str, main_name) " " prog_name_str
  76 # include "coreutils.h"
  77 # undef SINGLE_BINARY_PROGRAM
  78       ;
  79       printf ("\n\
  80 Built-in programs:\n\
  81 %s\n", prog_name_list);
  82 #endif
  83
  84       printf (_("\
  85 \n\
  86 Use: '%s --coreutils-prog=PROGRAM_NAME --help' for individual program help.\n"),
  87               program_name);
  88       emit_ancillary_info (PROGRAM_NAME);
  89     }
  90   exit (status);
  91 }
  92
  93 static void
  94 launch_program (char const *prog_name, int prog_argc, char **prog_argv)
  95 {
  96   int (*prog_main) (int, char **) = nullptr;
  97
  98   /* Ensure that at least one parameter was passed.  */
  99   if (!prog_argc || !prog_argv || !prog_argv[0] || !prog_name)
 100     return;
 101
 102 #ifdef SINGLE_BINARY
 103   if (false);
 104   /* Look up the right main program.  */
 105 # define SINGLE_BINARY_PROGRAM(prog_name_str, main_name) \
 106   else if (STREQ (prog_name_str, prog_name)) \
 107     prog_main = single_binary_main_##main_name;
 108 # include "coreutils.h"
 109 # undef SINGLE_BINARY_PROGRAM
 110 #endif
 111
 112   if (! prog_main)
 113     return;
 114
 115 #if HAVE_PRCTL && defined PR_SET_NAME
 116   /* Not being able to set the program name is not a fatal error.  */
 117   prctl (PR_SET_NAME, prog_argv[0]);
 118 #endif
 119 #if HAVE_PRCTL && defined PR_SET_MM_ARG_START
 120   /* Shift the beginning of the command line to prog_argv[0] (if set) so
 121      /proc/$pid/cmdline reflects a more specific value.  Note one needs
 122      CAP_SYS_RESOURCE or root privileges for this to succeed.  */
 123   prctl (PR_SET_MM, PR_SET_MM_ARG_START, prog_argv[0], 0, 0);
 124 #endif
 125
 126   exit (prog_main (prog_argc, prog_argv));
 127 }
 128
 129 int
 130 main (int argc, char **argv)
 131 {
 132   char *prog_name = last_component (argv[0]);
 133   int optc;
 134
 135   /* Map external name to internal name.  */
 136   char ginstall[] = "ginstall";
 137   if (STREQ (prog_name, "install"))
 138     prog_name = ginstall;
 139
 140   /* If this program is called directly as "coreutils" or if the value of
 141      argv[0] is an unknown tool (which "coreutils" is), we proceed and parse
 142      the options.  */
 143   launch_program (prog_name, argc, argv);
 144
 145   /* No known program was selected via argv[0].  Try parsing the first
 146      argument as --coreutils-prog=PROGRAM to determine the program.  The
 147      invocation for this case should be:
 148        path/to/coreutils --coreutils-prog=someprog someprog ...
 149      The third argument is what the program will see as argv[0].  */
 150
 151   if (argc >= 2)
 152     {
 153       size_t nskip = 0;
 154       char *arg_name = nullptr;
 155
 156       /* If calling coreutils directly, the "script" name isn't passed.
 157          Distinguish the two cases with a -shebang suffix.  */
 158       if (STRPREFIX (argv[1], "--coreutils-prog="))
 159         {
 160           nskip = 1;
 161           arg_name = prog_name = argv[1] + strlen ("--coreutils-prog=");
 162         }
 163       else if (STRPREFIX (argv[1], "--coreutils-prog-shebang="))
 164         {
 165           nskip = 2;
 166           prog_name = argv[1] + strlen ("--coreutils-prog-shebang=");
 167           if (argc >= 3)
 168             arg_name = last_component (argv[2]);
 169           else
 170             arg_name = prog_name;
 171         }
 172
 173       if (nskip)
 174         {
 175           argv[nskip] = arg_name; /* XXX: Discards any specified path.  */
 176           launch_program (prog_name, argc - nskip, argv + nskip);
 177           error (EXIT_FAILURE, 0, _("unknown program %s"),
 178                  quote (prog_name));
 179         }
 180     }
 181
 182   /* No known program was selected.  From here on, we behave like any other
 183      coreutils program.  */
 184   initialize_main (&argc, &argv);
 185   set_program_name (argv[0]);
 186   setlocale (LC_ALL, "");
 187   bindtextdomain (PACKAGE, LOCALEDIR);
 188   textdomain (PACKAGE);
 189   atexit (close_stdout);
 190
 191   if ((optc = getopt_long (argc, argv, "", long_options, nullptr)) != -1)
 192     switch (optc)
 193       {
 194       case_GETOPT_HELP_CHAR;
 195
 196       case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
 197       }
 198
 199   /* Only print the error message when no options have been passed
 200      to coreutils.  */
 201   if (optind == 1 && prog_name && !STREQ (prog_name, "coreutils"))
 202     error (0, 0, _("unknown program %s"),
 203            quote (prog_name));
 204
 205   usage (EXIT_FAILURE);
 206 }