mirror of git://gcc.gnu.org/git/gcc.git
432 lines
11 KiB
C
432 lines
11 KiB
C
/* Relative (relocatable) prefix support.
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Copyright (C) 1987-2019 Free Software Foundation, Inc.
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This file is part of libiberty.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA
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02110-1301, USA. */
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/*
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@deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, @
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const char *@var{bin_prefix}, const char *@var{prefix})
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Given three paths @var{progname}, @var{bin_prefix}, @var{prefix},
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return the path that is in the same position relative to
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@var{progname}'s directory as @var{prefix} is relative to
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@var{bin_prefix}. That is, a string starting with the directory
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portion of @var{progname}, followed by a relative pathname of the
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difference between @var{bin_prefix} and @var{prefix}.
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If @var{progname} does not contain any directory separators,
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@code{make_relative_prefix} will search @env{PATH} to find a program
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named @var{progname}. Also, if @var{progname} is a symbolic link,
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the symbolic link will be resolved.
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For example, if @var{bin_prefix} is @code{/alpha/beta/gamma/gcc/delta},
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@var{prefix} is @code{/alpha/beta/gamma/omega/}, and @var{progname} is
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@code{/red/green/blue/gcc}, then this function will return
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@code{/red/green/blue/../../omega/}.
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The return value is normally allocated via @code{malloc}. If no
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relative prefix can be found, return @code{NULL}.
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@end deftypefn
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#ifdef HAVE_STDLIB_H
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#include <stdlib.h>
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#endif
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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#ifdef HAVE_SYS_STAT_H
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#include <sys/stat.h>
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#endif
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#include <string.h>
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#include "ansidecl.h"
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#include "libiberty.h"
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#ifndef R_OK
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#define R_OK 4
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#define W_OK 2
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#define X_OK 1
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#endif
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#ifndef DIR_SEPARATOR
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# define DIR_SEPARATOR '/'
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#endif
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#if defined (_WIN32) || defined (__MSDOS__) \
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|| defined (__DJGPP__) || defined (__OS2__)
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# define HAVE_DOS_BASED_FILE_SYSTEM
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# define HAVE_HOST_EXECUTABLE_SUFFIX
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# define HOST_EXECUTABLE_SUFFIX ".exe"
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# ifndef DIR_SEPARATOR_2
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# define DIR_SEPARATOR_2 '\\'
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# endif
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# define PATH_SEPARATOR ';'
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#else
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# define PATH_SEPARATOR ':'
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#endif
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#ifndef DIR_SEPARATOR_2
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# define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
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#else
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# define IS_DIR_SEPARATOR(ch) \
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(((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
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#endif
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#define DIR_UP ".."
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static char *save_string (const char *, int);
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static char **split_directories (const char *, int *);
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static void free_split_directories (char **);
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static char *
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save_string (const char *s, int len)
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{
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char *result = (char *) malloc (len + 1);
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memcpy (result, s, len);
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result[len] = 0;
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return result;
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}
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/* Split a filename into component directories. */
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static char **
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split_directories (const char *name, int *ptr_num_dirs)
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{
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int num_dirs = 0;
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char **dirs;
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const char *p, *q;
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int ch;
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/* Count the number of directories. Special case MSDOS disk names as part
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of the initial directory. */
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p = name;
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#ifdef HAVE_DOS_BASED_FILE_SYSTEM
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if (name[1] == ':' && IS_DIR_SEPARATOR (name[2]))
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{
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p += 3;
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num_dirs++;
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}
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#endif /* HAVE_DOS_BASED_FILE_SYSTEM */
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while ((ch = *p++) != '\0')
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{
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if (IS_DIR_SEPARATOR (ch))
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{
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num_dirs++;
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while (IS_DIR_SEPARATOR (*p))
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p++;
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}
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}
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dirs = (char **) malloc (sizeof (char *) * (num_dirs + 2));
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if (dirs == NULL)
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return NULL;
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/* Now copy the directory parts. */
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num_dirs = 0;
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p = name;
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#ifdef HAVE_DOS_BASED_FILE_SYSTEM
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if (name[1] == ':' && IS_DIR_SEPARATOR (name[2]))
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{
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dirs[num_dirs++] = save_string (p, 3);
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if (dirs[num_dirs - 1] == NULL)
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{
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free (dirs);
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return NULL;
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}
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p += 3;
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}
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#endif /* HAVE_DOS_BASED_FILE_SYSTEM */
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q = p;
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while ((ch = *p++) != '\0')
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{
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if (IS_DIR_SEPARATOR (ch))
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{
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while (IS_DIR_SEPARATOR (*p))
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p++;
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dirs[num_dirs++] = save_string (q, p - q);
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if (dirs[num_dirs - 1] == NULL)
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{
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dirs[num_dirs] = NULL;
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free_split_directories (dirs);
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return NULL;
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}
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q = p;
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}
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}
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if (p - 1 - q > 0)
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dirs[num_dirs++] = save_string (q, p - 1 - q);
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dirs[num_dirs] = NULL;
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if (dirs[num_dirs - 1] == NULL)
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{
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free_split_directories (dirs);
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return NULL;
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}
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if (ptr_num_dirs)
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*ptr_num_dirs = num_dirs;
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return dirs;
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}
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/* Release storage held by split directories. */
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static void
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free_split_directories (char **dirs)
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{
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int i = 0;
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if (dirs != NULL)
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{
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while (dirs[i] != NULL)
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free (dirs[i++]);
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free ((char *) dirs);
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}
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}
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/* Given three strings PROGNAME, BIN_PREFIX, PREFIX, return a string that gets
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to PREFIX starting with the directory portion of PROGNAME and a relative
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pathname of the difference between BIN_PREFIX and PREFIX.
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For example, if BIN_PREFIX is /alpha/beta/gamma/gcc/delta, PREFIX is
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/alpha/beta/gamma/omega/, and PROGNAME is /red/green/blue/gcc, then this
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function will return /red/green/blue/../../omega/.
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If no relative prefix can be found, return NULL. */
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static char *
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make_relative_prefix_1 (const char *progname, const char *bin_prefix,
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const char *prefix, const int resolve_links)
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{
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char **prog_dirs = NULL, **bin_dirs = NULL, **prefix_dirs = NULL;
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int prog_num, bin_num, prefix_num;
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int i, n, common;
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int needed_len;
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char *ret = NULL, *ptr, *full_progname;
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char *alloc_ptr = NULL;
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if (progname == NULL || bin_prefix == NULL || prefix == NULL)
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return NULL;
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/* If there is no full pathname, try to find the program by checking in each
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of the directories specified in the PATH environment variable. */
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if (lbasename (progname) == progname)
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{
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char *temp;
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temp = getenv ("PATH");
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if (temp)
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{
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char *startp, *endp, *nstore;
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size_t prefixlen = strlen (temp) + 1;
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size_t len;
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if (prefixlen < 2)
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prefixlen = 2;
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len = prefixlen + strlen (progname) + 1;
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#ifdef HAVE_HOST_EXECUTABLE_SUFFIX
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len += strlen (HOST_EXECUTABLE_SUFFIX);
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#endif
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if (len < MAX_ALLOCA_SIZE)
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nstore = (char *) alloca (len);
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else
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alloc_ptr = nstore = (char *) malloc (len);
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startp = endp = temp;
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while (1)
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{
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if (*endp == PATH_SEPARATOR || *endp == 0)
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{
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if (endp == startp)
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{
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nstore[0] = '.';
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nstore[1] = DIR_SEPARATOR;
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nstore[2] = '\0';
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}
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else
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{
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memcpy (nstore, startp, endp - startp);
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if (! IS_DIR_SEPARATOR (endp[-1]))
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{
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nstore[endp - startp] = DIR_SEPARATOR;
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nstore[endp - startp + 1] = 0;
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}
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else
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nstore[endp - startp] = 0;
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}
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strcat (nstore, progname);
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if (! access (nstore, X_OK)
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#ifdef HAVE_HOST_EXECUTABLE_SUFFIX
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|| ! access (strcat (nstore, HOST_EXECUTABLE_SUFFIX), X_OK)
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#endif
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)
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{
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#if defined (HAVE_SYS_STAT_H) && defined (S_ISREG)
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struct stat st;
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if (stat (nstore, &st) >= 0 && S_ISREG (st.st_mode))
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#endif
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{
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progname = nstore;
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break;
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}
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}
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if (*endp == 0)
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break;
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endp = startp = endp + 1;
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}
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else
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endp++;
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}
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}
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}
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if (resolve_links)
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full_progname = lrealpath (progname);
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else
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full_progname = strdup (progname);
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if (full_progname == NULL)
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goto bailout;
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prog_dirs = split_directories (full_progname, &prog_num);
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free (full_progname);
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if (prog_dirs == NULL)
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goto bailout;
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bin_dirs = split_directories (bin_prefix, &bin_num);
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if (bin_dirs == NULL)
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goto bailout;
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/* Remove the program name from comparison of directory names. */
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prog_num--;
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/* If we are still installed in the standard location, we don't need to
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specify relative directories. Also, if argv[0] still doesn't contain
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any directory specifiers after the search above, then there is not much
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we can do. */
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if (prog_num == bin_num)
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{
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for (i = 0; i < bin_num; i++)
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{
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if (strcmp (prog_dirs[i], bin_dirs[i]) != 0)
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break;
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}
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if (prog_num <= 0 || i == bin_num)
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goto bailout;
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}
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prefix_dirs = split_directories (prefix, &prefix_num);
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if (prefix_dirs == NULL)
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goto bailout;
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/* Find how many directories are in common between bin_prefix & prefix. */
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n = (prefix_num < bin_num) ? prefix_num : bin_num;
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for (common = 0; common < n; common++)
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{
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if (strcmp (bin_dirs[common], prefix_dirs[common]) != 0)
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break;
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}
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/* If there are no common directories, there can be no relative prefix. */
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if (common == 0)
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goto bailout;
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/* Two passes: first figure out the size of the result string, and
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then construct it. */
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needed_len = 0;
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for (i = 0; i < prog_num; i++)
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needed_len += strlen (prog_dirs[i]);
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needed_len += sizeof (DIR_UP) * (bin_num - common);
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for (i = common; i < prefix_num; i++)
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needed_len += strlen (prefix_dirs[i]);
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needed_len += 1; /* Trailing NUL. */
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ret = (char *) malloc (needed_len);
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if (ret == NULL)
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goto bailout;
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/* Build up the pathnames in argv[0]. */
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*ret = '\0';
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for (i = 0; i < prog_num; i++)
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strcat (ret, prog_dirs[i]);
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/* Now build up the ..'s. */
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ptr = ret + strlen(ret);
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for (i = common; i < bin_num; i++)
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{
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strcpy (ptr, DIR_UP);
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ptr += sizeof (DIR_UP) - 1;
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*(ptr++) = DIR_SEPARATOR;
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}
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*ptr = '\0';
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/* Put in directories to move over to prefix. */
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for (i = common; i < prefix_num; i++)
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strcat (ret, prefix_dirs[i]);
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bailout:
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free_split_directories (prog_dirs);
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free_split_directories (bin_dirs);
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free_split_directories (prefix_dirs);
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free (alloc_ptr);
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return ret;
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}
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/* Do the full job, including symlink resolution.
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This path will find files installed in the same place as the
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program even when a soft link has been made to the program
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from somwhere else. */
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char *
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make_relative_prefix (const char *progname, const char *bin_prefix,
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const char *prefix)
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{
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return make_relative_prefix_1 (progname, bin_prefix, prefix, 1);
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}
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/* Make the relative pathname without attempting to resolve any links.
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'..' etc may also be left in the pathname.
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This will find the files the user meant the program to find if the
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installation is patched together with soft links. */
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char *
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make_relative_prefix_ignore_links (const char *progname,
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const char *bin_prefix,
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const char *prefix)
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{
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return make_relative_prefix_1 (progname, bin_prefix, prefix, 0);
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}
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