glibc/misc/mntent_r.c
Joseph Myers 84e5e75640 Fix fgets_unlocked namespace issues (bug 17664).
Various POSIX functions bring in res_init.o, res_hconf.o or
mntent_r.o, which use fgets_unlocked, which is not a POSIX function.
This patch arranges for them to use __fgets_unlocked instead.  (The
IS_IN (libc) conditional in rec_hconf.c is needed because that file is
also used in nscd.)

Tested for x86_64 (testsuite, and that disassembly of installed shared
libraries is unchanged by the patch except for an assertion line
number).  Note that most of the linknamespace tests that failed
because of fgets_unlocked from the resolver also fail because of other
symbols brought in by the resolver, so the number of XFAILs this
removes is limited.  Also note that fgets_unlocked failures for
unistd.h for XPG3/XPG4 showed up that actually unistd.h is declaring
too much for XPG3/XPG4 (bug 17665) - there is no actual need to make
getusershell.c use __fgets_unlocked (at least as regards formal
standards are concerned; maybe it should still change for
namespace-cleanness of _DEFAULT_SOURCE) because the functions there
aren't actually in any of the supported standards; the correct fix for
those failures will be to stop the *usershell* functions appearing in
unistd.h for XPG3/XPG4.

	[BZ #17664]
	* misc/mntent_r.c (__getmntent_r): Use __fgets_unlocked instead of
	fgets_unlocked.
	* resolv/res_hconf.c [IS_IN (libc)] (fgets_unlocked): Define to
	__fgets_unlocked.
	* resolv/res_init.c (__res_vinit): Use __fgets_unlocked instead of
	fgets_unlocked.
	* conform/Makefile (test-xfail-XPG4/sys/statvfs.h/linknamespace):
	Remove variable.
	(test-xfail-POSIX/sys/mman.h/linknamespace): Likewise.
	(test-xfail-UNIX98/sys/mman.h/linknamespace): Likewise.
	(test-xfail-UNIX98/sys/statvfs.h/linknamespace): Likewise.
	(test-xfail-XOPEN2K/sys/mman.h/linknamespace): Likewise.
	(test-xfail-XOPEN2K/sys/statvfs.h/linknamespace): Likewise.
	(test-xfail-POSIX2008/sys/mman.h/linknamespace): Likewise.
	(test-xfail-POSIX2008/sys/statvfs.h/linknamespace): Likewise.
	(test-xfail-XOPEN2K8/sys/mman.h/linknamespace): Likewise.
	(test-xfail-XOPEN2K8/sys/statvfs.h/linknamespace): Likewise.
2014-12-02 21:31:24 +00:00

291 lines
7.8 KiB
C

/* Utilities for reading/writing fstab, mtab, etc.
Copyright (C) 1995-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <alloca.h>
#include <mntent.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <string.h>
#include <sys/types.h>
#define flockfile(s) _IO_flockfile (s)
#define funlockfile(s) _IO_funlockfile (s)
#undef __setmntent
#undef __endmntent
#undef __getmntent_r
/* Prepare to begin reading and/or writing mount table entries from the
beginning of FILE. MODE is as for `fopen'. */
FILE *
__setmntent (const char *file, const char *mode)
{
/* Extend the mode parameter with "c" to disable cancellation in the
I/O functions and "e" to set FD_CLOEXEC. */
size_t modelen = strlen (mode);
char newmode[modelen + 3];
memcpy (mempcpy (newmode, mode, modelen), "ce", 3);
FILE *result = fopen (file, newmode);
if (result != NULL)
/* We do the locking ourselves. */
__fsetlocking (result, FSETLOCKING_BYCALLER);
return result;
}
libc_hidden_def (__setmntent)
weak_alias (__setmntent, setmntent)
/* Close a stream opened with `setmntent'. */
int
__endmntent (FILE *stream)
{
if (stream) /* SunOS 4.x allows for NULL stream */
fclose (stream);
return 1; /* SunOS 4.x says to always return 1 */
}
libc_hidden_def (__endmntent)
weak_alias (__endmntent, endmntent)
/* Since the values in a line are separated by spaces, a name cannot
contain a space. Therefore some programs encode spaces in names
by the strings "\040". We undo the encoding when reading an entry.
The decoding happens in place. */
static char *
decode_name (char *buf)
{
char *rp = buf;
char *wp = buf;
do
if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '4' && rp[3] == '0')
{
/* \040 is a SPACE. */
*wp++ = ' ';
rp += 3;
}
else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '1')
{
/* \011 is a TAB. */
*wp++ = '\t';
rp += 3;
}
else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '2')
{
/* \012 is a NEWLINE. */
*wp++ = '\n';
rp += 3;
}
else if (rp[0] == '\\' && rp[1] == '\\')
{
/* We have to escape \\ to be able to represent all characters. */
*wp++ = '\\';
rp += 1;
}
else if (rp[0] == '\\' && rp[1] == '1' && rp[2] == '3' && rp[3] == '4')
{
/* \134 is also \\. */
*wp++ = '\\';
rp += 3;
}
else
*wp++ = *rp;
while (*rp++ != '\0');
return buf;
}
/* Read one mount table entry from STREAM. Returns a pointer to storage
reused on the next call, or null for EOF or error (use feof/ferror to
check). */
struct mntent *
__getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
{
char *cp;
char *head;
flockfile (stream);
do
{
char *end_ptr;
if (__fgets_unlocked (buffer, bufsiz, stream) == NULL)
{
funlockfile (stream);
return NULL;
}
end_ptr = strchr (buffer, '\n');
if (end_ptr != NULL) /* chop newline */
*end_ptr = '\0';
else
{
/* Not the whole line was read. Do it now but forget it. */
char tmp[1024];
while (__fgets_unlocked (tmp, sizeof tmp, stream) != NULL)
if (strchr (tmp, '\n') != NULL)
break;
}
head = buffer + strspn (buffer, " \t");
/* skip empty lines and comment lines: */
}
while (head[0] == '\0' || head[0] == '#');
cp = __strsep (&head, " \t");
mp->mnt_fsname = cp != NULL ? decode_name (cp) : (char *) "";
if (head)
head += strspn (head, " \t");
cp = __strsep (&head, " \t");
mp->mnt_dir = cp != NULL ? decode_name (cp) : (char *) "";
if (head)
head += strspn (head, " \t");
cp = __strsep (&head, " \t");
mp->mnt_type = cp != NULL ? decode_name (cp) : (char *) "";
if (head)
head += strspn (head, " \t");
cp = __strsep (&head, " \t");
mp->mnt_opts = cp != NULL ? decode_name (cp) : (char *) "";
switch (head ? sscanf (head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno) : 0)
{
case 0:
mp->mnt_freq = 0;
case 1:
mp->mnt_passno = 0;
case 2:
break;
}
funlockfile (stream);
return mp;
}
libc_hidden_def (__getmntent_r)
weak_alias (__getmntent_r, getmntent_r)
/* We have to use an encoding for names if they contain spaces or tabs.
To be able to represent all characters we also have to escape the
backslash itself. This "function" must be a macro since we use
`alloca'. */
#define encode_name(name) \
do { \
const char *rp = name; \
\
while (*rp != '\0') \
if (*rp == ' ' || *rp == '\t' || *rp == '\n' || *rp == '\\') \
break; \
else \
++rp; \
\
if (*rp != '\0') \
{ \
/* In the worst case the length of the string can increase to \
four times the current length. */ \
char *wp; \
\
rp = name; \
name = wp = (char *) alloca (strlen (name) * 4 + 1); \
\
do \
if (*rp == ' ') \
{ \
*wp++ = '\\'; \
*wp++ = '0'; \
*wp++ = '4'; \
*wp++ = '0'; \
} \
else if (*rp == '\t') \
{ \
*wp++ = '\\'; \
*wp++ = '0'; \
*wp++ = '1'; \
*wp++ = '1'; \
} \
else if (*rp == '\n') \
{ \
*wp++ = '\\'; \
*wp++ = '0'; \
*wp++ = '1'; \
*wp++ = '2'; \
} \
else if (*rp == '\\') \
{ \
*wp++ = '\\'; \
*wp++ = '\\'; \
} \
else \
*wp++ = *rp; \
while (*rp++ != '\0'); \
} \
} while (0)
/* Write the mount table entry described by MNT to STREAM.
Return zero on success, nonzero on failure. */
int
__addmntent (FILE *stream, const struct mntent *mnt)
{
struct mntent mntcopy = *mnt;
if (fseek (stream, 0, SEEK_END))
return 1;
/* Encode spaces and tabs in the names. */
encode_name (mntcopy.mnt_fsname);
encode_name (mntcopy.mnt_dir);
encode_name (mntcopy.mnt_type);
encode_name (mntcopy.mnt_opts);
return (fprintf (stream, "%s %s %s %s %d %d\n",
mntcopy.mnt_fsname,
mntcopy.mnt_dir,
mntcopy.mnt_type,
mntcopy.mnt_opts,
mntcopy.mnt_freq,
mntcopy.mnt_passno) < 0
|| fflush (stream) != 0);
}
weak_alias (__addmntent, addmntent)
/* Search MNT->mnt_opts for an option matching OPT.
Returns the address of the substring, or null if none found. */
char *
__hasmntopt (const struct mntent *mnt, const char *opt)
{
const size_t optlen = strlen (opt);
char *rest = mnt->mnt_opts, *p;
while ((p = strstr (rest, opt)) != NULL)
{
if ((p == rest || p[-1] == ',')
&& (p[optlen] == '\0' || p[optlen] == '=' || p[optlen] == ','))
return p;
rest = strchr (p, ',');
if (rest == NULL)
break;
++rest;
}
return NULL;
}
weak_alias (__hasmntopt, hasmntopt)