grub/grub-core/osdep/unix/relpath.c

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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2006,2007,2008,2009,2010,2011,2012,2013 Free Software Foundation, Inc.
*
* GRUB 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 3 of the License, or
* (at your option) any later version.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <config-util.h>
#include <config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <grub/util/misc.h>
#include <grub/emu/hostdisk.h>
#include <grub/emu/getroot.h>
#include <grub/mm.h>
/* This function never prints trailing slashes (so that its output
can be appended a slash unconditionally). */
char *
grub_make_system_path_relative_to_its_root (const char *path)
{
struct stat st;
char *p, *buf, *buf2, *buf3, *ret;
uintptr_t offset = 0;
dev_t num;
size_t len;
char *poolfs = NULL;
/* canonicalize. */
p = grub_canonicalize_file_name (path);
if (p == NULL)
grub_util_error (_("failed to get canonical path of `%s'"), path);
#ifdef __linux__
ret = grub_make_system_path_relative_to_its_root_os (p);
if (ret)
return ret;
#endif
/* For ZFS sub-pool filesystems. */
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#ifndef __HAIKU__
{
char *dummy;
grub_find_zpool_from_dir (p, &dummy, &poolfs);
}
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#endif
len = strlen (p) + 1;
buf = xstrdup (p);
free (p);
if (stat (buf, &st) < 0)
grub_util_error (_("cannot stat `%s': %s"), buf, strerror (errno));
buf2 = xstrdup (buf);
num = st.st_dev;
/* This loop sets offset to the number of chars of the root
directory we're inspecting. */
while (1)
{
p = strrchr (buf, '/');
if (p == NULL)
/* This should never happen. */
grub_util_error ("%s",
/* TRANSLATORS: canonical pathname is the
complete one e.g. /etc/fstab. It has
to contain `/' normally, if it doesn't
we're in trouble and throw this error. */
_("no `/' in canonical filename"));
if (p != buf)
*p = 0;
else
*++p = 0;
if (stat (buf, &st) < 0)
grub_util_error (_("cannot stat `%s': %s"), buf, strerror (errno));
/* buf is another filesystem; we found it. */
if (st.st_dev != num)
{
/* offset == 0 means path given is the mount point.
This works around special-casing of "/" in Un*x. This function never
prints trailing slashes (so that its output can be appended a slash
unconditionally). Each slash in is considered a preceding slash, and
therefore the root directory is an empty string. */
if (offset == 0)
{
free (buf);
free (buf2);
if (poolfs)
return xasprintf ("/%s/@", poolfs);
return xstrdup ("");
}
else
break;
}
offset = p - buf;
/* offset == 1 means root directory. */
if (offset == 1)
{
/* Include leading slash. */
offset = 0;
break;
}
}
free (buf);
buf3 = xstrdup (buf2 + offset);
buf2[offset] = 0;
free (buf2);
/* Remove trailing slashes, return empty string if root directory. */
len = strlen (buf3);
while (len > 0 && buf3[len - 1] == '/')
{
buf3[len - 1] = '\0';
len--;
}
if (poolfs)
{
ret = xasprintf ("/%s/@%s", poolfs, buf3);
free (buf3);
}
else
ret = buf3;
return ret;
}