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Re: Add make_relative_prefix to libiberty
Ping. DJ approved the libiberty parts of this patch; I'd like to
commit it so that I can make ld and gdb use it, but it needs to go in
with the GCC bits.
On Mon, Nov 18, 2002 at 08:34:38PM -0500, Daniel Jacobowitz wrote:
> 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;
> +}
>
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer