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      1 /* Program name management.
      2    Copyright (C) 2001-2003, 2005-2012 Free Software Foundation, Inc.
      3    Written by Bruno Haible <bruno (at) 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 }
     93