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Re: Add make_relative_prefix to libiberty
On Mon, Nov 18, 2002 at 07:52:51PM -0500, DJ Delorie wrote:
>
> > Which header? I do not see allocation rules, just a list of how
> > different functions in libiberty allocate memory. A number of them use
> > xmalloc to do it. Much simpler for an initialization function like
> > this one.
>
> All I'm looking for is a short note in the header where the
> declaration is (like "return value must be free'd by caller").
Oh, I see.
> > > You have also changed the copyright terms (GPL -> LGPL). Do you have
> > > the FSF's permission to do so?
> >
> > No. It was just me being sloppy; I apologize. I copied the wrong
> > copyright notice; I think I grabbed it from lbasename. Since I see a
> > number of GPL source files in libiberty, I assume that there is no
> > problem with adding a GPL'd source file to the libiberty directory?
>
> Depends. If this function is primarily for GPL'd applications, I
> don't see a problem. We've had cases where we want the "GPL plus
> exception" for libstdc++, but I don't think this is the case. but we
> can't change it anyway, so we might as well keep it GPL.
>
> > +This file is part of GCC.
> > +
> > +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. */
>
> Obviously, we shouldn't use "GCC" here ;-)
Just quoting :) Should all the rest of the files in libiberty be
updated to say they belong to libiberty? There's one from GDB
(floatformat), one from GNU C Library (regex.c; that one's actually
mastered elsewhere IIRC?), and several from GNU CC or GNU C Compiler.
> > +/*
> > +
> > +@deftypefn Extension {const char*} make_relative_prefix (const char *@var{progname}, const char *@var{bin_prefix}, const char *@var{prefix})
> > +
> > +Given pointers to the @code{argv[0]}, the default installation directory
> > +for this program, and the default location of another directory, this function
> > +returns the path to the other directory assuming the installation tree has moved
> > +from @var{bin_prefix} to the new location of @var{progname}.
>
> Hmmm.. could we add a note about the rv's allocation here?
>
> And the big comment above make_relative_prefix itself has the text
> which should go here. That's basically what I did when I did the
> original set of docs - just resyntaxed the comments into texinfo.
Okie.
> > +#include "ansidecl.h"
> > +#include "libiberty.h"
>
> The Makefile still has dependencies on obstack.h
Fixed. While I was at it, I updated the docs and big comment to be
actually _accurate_. If you work through the example that's been
sitting there for a while, you'll notice it doesn't make much sense...
Updated with your corrections. If this is OK with DJ, would a GCC
maintainer please approve the move out of gcc.c?
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
2002-11-18 Daniel Jacobowitz <drow@mvista.com>
* libiberty.h (make_relative_prefix): Add prototype.
2002-11-18 Daniel Jacobowitz <drow@mvista.com>
* Makefile.in: Add make-relative-prefix.c.
* make-relative-prefix.c: New file.
* functions.texi: Rebuilt.
2002-11-18 Daniel Jacobowitz <drow@mvista.com>
* gcc.c (make_relative_prefix, split_directories)
(free_split_directories): Removed.
Index: gcc/gcc.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/gcc.c,v
retrieving revision 1.344
diff -u -p -r1.344 gcc.c
--- gcc/gcc.c 14 Oct 2002 07:15:38 -0000 1.344
+++ gcc/gcc.c 19 Nov 2002 01:30:22 -0000
@@ -267,11 +267,6 @@ static struct rusage rus, prus;
struct path_prefix;
static void init_spec PARAMS ((void));
-#ifndef VMS
-static char **split_directories PARAMS ((const char *, int *));
-static void free_split_directories PARAMS ((char **));
-static char *make_relative_prefix PARAMS ((const char *, const char *, const char *));
-#endif /* VMS */
static void store_arg PARAMS ((const char *, int, int));
static char *load_specs PARAMS ((const char *));
static void read_specs PARAMS ((const char *, int));
@@ -2249,246 +2244,6 @@ putenv_from_prefixes (paths, env_var)
{
putenv (build_search_list (paths, env_var, 1));
}
-
-#ifndef VMS
-
-/* FIXME: the location independence code for VMS is hairier than this,
- and hasn't been written. */
-
-/* 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 **) xmalloc (sizeof (char *) * (num_dirs + 2));
-
- /* 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);
- 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);
- q = p;
- }
- }
-
- if (p - 1 - q > 0)
- dirs[num_dirs++] = save_string (q, p - 1 - q);
-
- dirs[num_dirs] = 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. */
-
-static 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, std_loc_p;
- int i, n, common;
-
- prog_dirs = split_directories (progname, &prog_num);
- bin_dirs = split_directories (bin_prefix, &bin_num);
-
- /* 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;
-
- GET_ENVIRONMENT (temp, "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);
- break;
- }
-
- if (*endp == 0)
- break;
- endp = startp = endp + 1;
- }
- else
- endp++;
- }
- }
- }
-
- /* Remove the program name from comparison of directory names. */
- prog_num--;
-
- /* Determine if the compiler is installed in the standard location, and if
- so, we don't need to specify relative directories. Also, if argv[0]
- doesn't contain any directory specifiers, there is not much we can do. */
- std_loc_p = 0;
- 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)
- {
- std_loc_p = 1;
- 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);
-
- /* 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;
- }
-
- /* Build up the pathnames in argv[0]. */
- for (i = 0; i < prog_num; i++)
- obstack_grow (&obstack, prog_dirs[i], strlen (prog_dirs[i]));
-
- /* Now build up the ..'s. */
- for (i = common; i < n; i++)
- {
- obstack_grow (&obstack, DIR_UP, sizeof (DIR_UP) - 1);
- obstack_1grow (&obstack, DIR_SEPARATOR);
- }
-
- /* Put in directories to move over to prefix. */
- for (i = common; i < prefix_num; i++)
- obstack_grow (&obstack, prefix_dirs[i], strlen (prefix_dirs[i]));
-
- free_split_directories (prog_dirs);
- free_split_directories (bin_dirs);
- free_split_directories (prefix_dirs);
-
- obstack_1grow (&obstack, '\0');
- return obstack_finish (&obstack);
-}
-#endif /* VMS */
/* Check whether NAME can be accessed in MODE. This is like access,
except that it never considers directories to be executable. */
Index: include/libiberty.h
===================================================================
RCS file: /cvs/gcc/gcc/include/libiberty.h,v
retrieving revision 1.29
diff -u -p -r1.29 libiberty.h
--- include/libiberty.h 20 Sep 2002 00:21:54 -0000 1.29
+++ include/libiberty.h 19 Nov 2002 01:30:23 -0000
@@ -145,6 +145,12 @@ extern char * getpwd PARAMS ((void));
extern long get_run_time PARAMS ((void));
+/* Generate a relocated path to some installation directory. Allocates
+ return value using malloc. */
+
+extern char *make_relative_prefix PARAMS ((const char *, const char *,
+ const char *));
+
/* Choose a temporary directory to use for scratch files. */
extern char *choose_temp_base PARAMS ((void)) ATTRIBUTE_MALLOC;
Index: libiberty/Makefile.in
===================================================================
RCS file: /cvs/gcc/gcc/libiberty/Makefile.in,v
retrieving revision 1.77
diff -u -p -r1.77 Makefile.in
--- libiberty/Makefile.in 23 Sep 2002 03:52:51 -0000 1.77
+++ libiberty/Makefile.in 19 Nov 2002 01:30:24 -0000
@@ -135,6 +135,7 @@ CFILES = alloca.c argv.c asprintf.c atex
hashtab.c hex.c \
index.c insque.c \
lbasename.c \
+ make-relative-prefix.c \
make-temp-file.c md5.c memchr.c memcmp.c memcpy.c memmove.c \
memset.c mkstemps.c \
objalloc.c obstack.c \
@@ -159,6 +160,7 @@ REQUIRED_OFILES = regex.o cplus-dem.o cp
getopt.o getopt1.o getpwd.o getruntime.o \
hashtab.o hex.o \
lbasename.o \
+ make-relative-prefix.o \
make-temp-file.o \
objalloc.o obstack.o \
partition.o pexecute.o \
@@ -432,6 +434,7 @@ hashtab.o: config.h $(INCDIR)/ansidecl.h
hex.o: $(INCDIR)/ansidecl.h $(INCDIR)/libiberty.h
lbasename.o: $(INCDIR)/ansidecl.h $(INCDIR)/libiberty.h \
$(INCDIR)/safe-ctype.h
+make-relative-prefix.o: config.h $(INCDIR)/ansidecl.h $(INCDIR)/libiberty.h
make-temp-file.o: config.h $(INCDIR)/ansidecl.h $(INCDIR)/libiberty.h
md5.o: config.h $(INCDIR)/ansidecl.h $(INCDIR)/md5.h
memchr.o: $(INCDIR)/ansidecl.h
Index: libiberty/functions.texi
===================================================================
RCS file: /cvs/gcc/gcc/libiberty/functions.texi,v
retrieving revision 1.8
diff -u -p -r1.8 functions.texi
--- libiberty/functions.texi 28 Mar 2002 04:04:20 -0000 1.8
+++ libiberty/functions.texi 19 Nov 2002 01:30:24 -0000
@@ -276,7 +276,7 @@ itself.
@end deftypefn
-@c getruntime.c:78
+@c getruntime.c:82
@deftypefn Replacement long get_run_time (void)
Returns the time used so far, in microseconds. If possible, this is
@@ -322,11 +322,12 @@ between calls to @code{getpwd}.
Initializes the array mapping the current character set to
corresponding hex values. This function must be called before any
-call to @code{hex_p} or @code{hex_value}.
+call to @code{hex_p} or @code{hex_value}. If you fail to call it, a
+default ASCII-based table will normally be used on ASCII systems.
@end deftypefn
-@c hex.c:33
+@c hex.c:34
@deftypefn Extension int hex_p (int @var{c})
Evaluates to non-zero if the given character is a valid hex character,
@@ -335,7 +336,7 @@ or zero if it is not. Note that the val
@end deftypefn
-@c hex.c:41
+@c hex.c:42
@deftypefn Extension int hex_value (int @var{c})
Returns the numeric equivalent of the given character when interpreted
@@ -388,6 +389,22 @@ strings for particular input.
In particular, the empty string returns the same empty string,
and a path ending in @code{/} returns the empty string after it.
+
+@end deftypefn
+
+@c make-relative-prefix.c:24
+@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
Index: libiberty/make-relative-prefix.c
===================================================================
RCS file: libiberty/make-relative-prefix.c
diff -N libiberty/make-relative-prefix.c
--- /dev/null 1 Jan 1970 00:00:00 -0000
+++ libiberty/make-relative-prefix.c 19 Nov 2002 01:30:24 -0000
@@ -0,0 +1,387 @@
+/* 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;
+}