--- /dev/null
+/* Relative (relocatable) prefix support.
+ Copyright (C) 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
+ 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+
+This file is part of libiberty.
+
+GCC is free software; you can redistribute it and/or modify it under
+the terms of the GNU General Public License as published by the Free
+Software Foundation; either version 2, or (at your option) any later
+version.
+
+GCC is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or
+FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING. If not, write to the Free
+Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+02111-1307, USA. */
+
+/*
+
+@deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, const char *@var{bin_prefix}, const char *@var{prefix})
+
+Given three strings @var{progname}, @var{bin_prefix}, @var{prefix}, return a string
+that gets to @var{prefix} starting with the directory portion of @var{progname} and
+a relative pathname of the difference between @var{bin_prefix} and @var{prefix}.
+
+For example, if @var{bin_prefix} is @code{/alpha/beta/gamma/gcc/delta}, @var{prefix}
+is @code{/alpha/beta/gamma/omega/}, and @var{progname} is @code{/red/green/blue/gcc},
+then this function will return @code{/red/green/blue/../../omega/}.
+
+The return value is normally allocated via @code{malloc}. If no relative prefix
+can be found, return @code{NULL}.
+
+@end deftypefn
+
+*/
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_STDLIB_H
+#include <stdlib.h>
+#endif
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <string.h>
+
+#include "ansidecl.h"
+#include "libiberty.h"
+
+#ifndef R_OK
+#define R_OK 4
+#define W_OK 2
+#define X_OK 1
+#endif
+
+#ifndef DIR_SEPARATOR
+# define DIR_SEPARATOR '/'
+#endif
+
+#if defined (_WIN32) || defined (__MSDOS__) \
+ || defined (__DJGPP__) || defined (__OS2__)
+# define HAVE_DOS_BASED_FILE_SYSTEM
+# define HOST_EXECUTABLE_SUFFIX ".exe"
+# ifndef DIR_SEPARATOR_2
+# define DIR_SEPARATOR_2 '\\'
+# endif
+# define PATH_SEPARATOR ';'
+#else
+# define PATH_SEPARATOR ':'
+#endif
+
+#ifndef DIR_SEPARATOR_2
+# define IS_DIR_SEPARATOR(ch) ((ch) == DIR_SEPARATOR)
+#else
+# define IS_DIR_SEPARATOR(ch) \
+ (((ch) == DIR_SEPARATOR) || ((ch) == DIR_SEPARATOR_2))
+#endif
+
+#define DIR_UP ".."
+
+static char *save_string PARAMS ((const char *, int));
+static char **split_directories PARAMS ((const char *, int *));
+static void free_split_directories PARAMS ((char **));
+
+static char *
+save_string (s, len)
+ const char *s;
+ int len;
+{
+ char *result = malloc (len + 1);
+
+ memcpy (result, s, len);
+ result[len] = 0;
+ return result;
+}
+
+/* Split a filename into component directories. */
+
+static char **
+split_directories (name, ptr_num_dirs)
+ const char *name;
+ int *ptr_num_dirs;
+{
+ int num_dirs = 0;
+ char **dirs;
+ const char *p, *q;
+ int ch;
+
+ /* Count the number of directories. Special case MSDOS disk names as part
+ of the initial directory. */
+ p = name;
+#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+ if (name[1] == ':' && IS_DIR_SEPARATOR (name[2]))
+ {
+ p += 3;
+ num_dirs++;
+ }
+#endif /* HAVE_DOS_BASED_FILE_SYSTEM */
+
+ while ((ch = *p++) != '\0')
+ {
+ if (IS_DIR_SEPARATOR (ch))
+ {
+ num_dirs++;
+ while (IS_DIR_SEPARATOR (*p))
+ p++;
+ }
+ }
+
+ dirs = (char **) malloc (sizeof (char *) * (num_dirs + 2));
+ if (dirs == NULL)
+ return NULL;
+
+ /* Now copy the directory parts. */
+ num_dirs = 0;
+ p = name;
+#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+ if (name[1] == ':' && IS_DIR_SEPARATOR (name[2]))
+ {
+ dirs[num_dirs++] = save_string (p, 3);
+ if (dirs[num_dirs - 1] == NULL)
+ {
+ free (dirs);
+ return NULL;
+ }
+ p += 3;
+ }
+#endif /* HAVE_DOS_BASED_FILE_SYSTEM */
+
+ q = p;
+ while ((ch = *p++) != '\0')
+ {
+ if (IS_DIR_SEPARATOR (ch))
+ {
+ while (IS_DIR_SEPARATOR (*p))
+ p++;
+
+ dirs[num_dirs++] = save_string (q, p - q);
+ if (dirs[num_dirs - 1] == NULL)
+ {
+ dirs[num_dirs] = NULL;
+ free_split_directories (dirs);
+ return NULL;
+ }
+ q = p;
+ }
+ }
+
+ if (p - 1 - q > 0)
+ dirs[num_dirs++] = save_string (q, p - 1 - q);
+ dirs[num_dirs] = NULL;
+
+ if (dirs[num_dirs - 1] == NULL)
+ {
+ free_split_directories (dirs);
+ return NULL;
+ }
+
+ if (ptr_num_dirs)
+ *ptr_num_dirs = num_dirs;
+ return dirs;
+}
+
+/* Release storage held by split directories. */
+
+static void
+free_split_directories (dirs)
+ char **dirs;
+{
+ int i = 0;
+
+ while (dirs[i] != NULL)
+ free (dirs[i++]);
+
+ free ((char *) dirs);
+}
+
+/* Given three strings PROGNAME, BIN_PREFIX, PREFIX, return a string that gets
+ to PREFIX starting with the directory portion of PROGNAME and a relative
+ pathname of the difference between BIN_PREFIX and PREFIX.
+
+ For example, if BIN_PREFIX is /alpha/beta/gamma/gcc/delta, PREFIX is
+ /alpha/beta/gamma/omega/, and PROGNAME is /red/green/blue/gcc, then this
+ function will return /red/green/blue/../../omega/.
+
+ If no relative prefix can be found, return NULL. */
+
+char *
+make_relative_prefix (progname, bin_prefix, prefix)
+ const char *progname;
+ const char *bin_prefix;
+ const char *prefix;
+{
+ char **prog_dirs, **bin_dirs, **prefix_dirs;
+ int prog_num, bin_num, prefix_num;
+ int i, n, common;
+ int needed_len;
+ char *ret, *ptr;
+
+ if (progname == NULL || bin_prefix == NULL || prefix == NULL)
+ return NULL;
+
+ prog_dirs = split_directories (progname, &prog_num);
+ bin_dirs = split_directories (bin_prefix, &bin_num);
+ if (bin_dirs == NULL || prog_dirs == NULL)
+ return NULL;
+
+ /* If there is no full pathname, try to find the program by checking in each
+ of the directories specified in the PATH environment variable. */
+ if (prog_num == 1)
+ {
+ char *temp;
+
+ temp = getenv ("PATH");
+ if (temp)
+ {
+ char *startp, *endp, *nstore;
+ size_t prefixlen = strlen (temp) + 1;
+ if (prefixlen < 2)
+ prefixlen = 2;
+
+ nstore = (char *) alloca (prefixlen + strlen (progname) + 1);
+
+ startp = endp = temp;
+ while (1)
+ {
+ if (*endp == PATH_SEPARATOR || *endp == 0)
+ {
+ if (endp == startp)
+ {
+ nstore[0] = '.';
+ nstore[1] = DIR_SEPARATOR;
+ nstore[2] = '\0';
+ }
+ else
+ {
+ strncpy (nstore, startp, endp - startp);
+ if (! IS_DIR_SEPARATOR (endp[-1]))
+ {
+ nstore[endp - startp] = DIR_SEPARATOR;
+ nstore[endp - startp + 1] = 0;
+ }
+ else
+ nstore[endp - startp] = 0;
+ }
+ strcat (nstore, progname);
+ if (! access (nstore, X_OK)
+#ifdef HAVE_HOST_EXECUTABLE_SUFFIX
+ || ! access (strcat (nstore, HOST_EXECUTABLE_SUFFIX), X_OK)
+#endif
+ )
+ {
+ free_split_directories (prog_dirs);
+ progname = nstore;
+ prog_dirs = split_directories (progname, &prog_num);
+ if (prog_dirs == NULL)
+ {
+ free_split_directories (bin_dirs);
+ return NULL;
+ }
+ break;
+ }
+
+ if (*endp == 0)
+ break;
+ endp = startp = endp + 1;
+ }
+ else
+ endp++;
+ }
+ }
+ }
+
+ /* Remove the program name from comparison of directory names. */
+ prog_num--;
+
+ /* If we are still installed in the standard location, we don't need to
+ specify relative directories. Also, if argv[0] still doesn't contain
+ any directory specifiers after the search above, then there is not much
+ we can do. */
+ if (prog_num == bin_num)
+ {
+ for (i = 0; i < bin_num; i++)
+ {
+ if (strcmp (prog_dirs[i], bin_dirs[i]) != 0)
+ break;
+ }
+
+ if (prog_num <= 0 || i == bin_num)
+ {
+ free_split_directories (prog_dirs);
+ free_split_directories (bin_dirs);
+ prog_dirs = bin_dirs = (char **) 0;
+ return NULL;
+ }
+ }
+
+ prefix_dirs = split_directories (prefix, &prefix_num);
+ if (prefix_dirs == NULL)
+ {
+ free_split_directories (prog_dirs);
+ free_split_directories (bin_dirs);
+ return NULL;
+ }
+
+ /* Find how many directories are in common between bin_prefix & prefix. */
+ n = (prefix_num < bin_num) ? prefix_num : bin_num;
+ for (common = 0; common < n; common++)
+ {
+ if (strcmp (bin_dirs[common], prefix_dirs[common]) != 0)
+ break;
+ }
+
+ /* If there are no common directories, there can be no relative prefix. */
+ if (common == 0)
+ {
+ free_split_directories (prog_dirs);
+ free_split_directories (bin_dirs);
+ free_split_directories (prefix_dirs);
+ return NULL;
+ }
+
+ /* Two passes: first figure out the size of the result string, and
+ then construct it. */
+ needed_len = 0;
+ for (i = 0; i < prog_num; i++)
+ needed_len += strlen (prog_dirs[i]);
+ needed_len += sizeof (DIR_UP) * (bin_num - common);
+ for (i = common; i < prefix_num; i++)
+ needed_len += strlen (prefix_dirs[i]);
+ needed_len += 1; /* Trailing NUL. */
+
+ ret = (char *) malloc (needed_len);
+ if (ret == NULL)
+ return NULL;
+
+ /* Build up the pathnames in argv[0]. */
+ for (i = 0; i < prog_num; i++)
+ strcat (ret, prog_dirs[i]);
+
+ /* Now build up the ..'s. */
+ ptr = ret + strlen(ret);
+ for (i = common; i < bin_num; i++)
+ {
+ strcpy (ptr, DIR_UP);
+ ptr += sizeof (DIR_UP) - 1;
+ *(ptr++) = DIR_SEPARATOR;
+ }
+ *ptr = '\0';
+
+ /* Put in directories to move over to prefix. */
+ for (i = common; i < prefix_num; i++)
+ strcat (ret, prefix_dirs[i]);
+
+ free_split_directories (prog_dirs);
+ free_split_directories (bin_dirs);
+ free_split_directories (prefix_dirs);
+
+ return ret;
+}
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