contrib/grep/lib/progname.c

   1 /* Program name management.
   2    Copyright (C) 2001-2003, 2005-2015 Free Software Foundation, Inc.
   3    Written by Bruno Haible <bruno@clisp.org>, 2001.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18
  19 #include <config.h>
  20
  21 /* Specification.  */
  22 #undef ENABLE_RELOCATABLE /* avoid defining set_program_name as a macro */
  23 #include "progname.h"
  24
  25 #include <errno.h> /* get program_invocation_name declaration */
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30
  31 /* String containing name the program is called with.
  32    To be initialized by main().  */
  33 const char *program_name = NULL;
  34
  35 /* Set program_name, based on argv[0].
  36    argv0 must be a string allocated with indefinite extent, and must not be
  37    modified after this call.  */
  38 void
  39 set_program_name (const char *argv0)
  40 {
  41   /* libtool creates a temporary executable whose name is sometimes prefixed
  42      with "lt-" (depends on the platform).  It also makes argv[0] absolute.
  43      But the name of the temporary executable is a detail that should not be
  44      visible to the end user and to the test suite.
  45      Remove this "<dirname>/.libs/" or "<dirname>/.libs/lt-" prefix here.  */
  46   const char *slash;
  47   const char *base;
  48
  49   /* Sanity check.  POSIX requires the invoking process to pass a non-NULL
  50      argv[0].  */
  51   if (argv0 == NULL)
  52     {
  53       /* It's a bug in the invoking program.  Help diagnosing it.  */
  54       fputs ("A NULL argv[0] was passed through an exec system call.\n",
  55              stderr);
  56       abort ();
  57     }
  58
  59   slash = strrchr (argv0, '/');
  60   base = (slash != NULL ? slash + 1 : argv0);
  61   if (base - argv0 >= 7 && strncmp (base - 7, "/.libs/", 7) == 0)
  62     {
  63       argv0 = base;
  64       if (strncmp (base, "lt-", 3) == 0)
  65         {
  66           argv0 = base + 3;
  67           /* On glibc systems, remove the "lt-" prefix from the variable
  68              program_invocation_short_name.  */
  69 #if HAVE_DECL_PROGRAM_INVOCATION_SHORT_NAME
  70           program_invocation_short_name = (char *) argv0;
  71 #endif
  72         }
  73     }
  74
  75   /* But don't strip off a leading <dirname>/ in general, because when the user
  76      runs
  77          /some/hidden/place/bin/cp foo foo
  78      he should get the error message
  79          /some/hidden/place/bin/cp: `foo' and `foo' are the same file
  80      not
  81          cp: `foo' and `foo' are the same file
  82    */
  83
  84   program_name = argv0;
  85
  86   /* On glibc systems, the error() function comes from libc and uses the
  87      variable program_invocation_name, not program_name.  So set this variable
  88      as well.  */
  89 #if HAVE_DECL_PROGRAM_INVOCATION_NAME
  90   program_invocation_name = (char *) argv0;
  91 #endif
  92 }