293 lines
7.8 KiB
C
293 lines
7.8 KiB
C
/* Utilities for reading/writing fstab, mtab, etc.
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Copyright (C) 1995-2000, 2001, 2002, 2003, 2006, 2010, 2011
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Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <alloca.h>
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#include <mntent.h>
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#include <stdio.h>
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#include <stdio_ext.h>
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#include <string.h>
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#include <sys/types.h>
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#define flockfile(s) _IO_flockfile (s)
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#define funlockfile(s) _IO_funlockfile (s)
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#undef __setmntent
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#undef __endmntent
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#undef __getmntent_r
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/* Prepare to begin reading and/or writing mount table entries from the
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beginning of FILE. MODE is as for `fopen'. */
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FILE *
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__setmntent (const char *file, const char *mode)
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{
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/* Extend the mode parameter with "c" to disable cancellation in the
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I/O functions. */
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size_t modelen = strlen (mode);
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char newmode[modelen + 2];
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memcpy (mempcpy (newmode, mode, modelen), "c", 2);
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FILE *result = fopen (file, newmode);
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if (result != NULL)
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/* We do the locking ourselves. */
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__fsetlocking (result, FSETLOCKING_BYCALLER);
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return result;
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}
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INTDEF(__setmntent)
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weak_alias (__setmntent, setmntent)
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/* Close a stream opened with `setmntent'. */
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int
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__endmntent (FILE *stream)
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{
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if (stream) /* SunOS 4.x allows for NULL stream */
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fclose (stream);
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return 1; /* SunOS 4.x says to always return 1 */
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}
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INTDEF(__endmntent)
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weak_alias (__endmntent, endmntent)
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/* Since the values in a line are separated by spaces, a name cannot
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contain a space. Therefore some programs encode spaces in names
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by the strings "\040". We undo the encoding when reading an entry.
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The decoding happens in place. */
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static char *
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decode_name (char *buf)
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{
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char *rp = buf;
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char *wp = buf;
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do
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if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '4' && rp[3] == '0')
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{
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/* \040 is a SPACE. */
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*wp++ = ' ';
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rp += 3;
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}
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else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '1')
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{
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/* \011 is a TAB. */
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*wp++ = '\t';
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rp += 3;
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}
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else if (rp[0] == '\\' && rp[1] == '0' && rp[2] == '1' && rp[3] == '2')
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{
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/* \012 is a NEWLINE. */
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*wp++ = '\n';
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rp += 3;
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}
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else if (rp[0] == '\\' && rp[1] == '\\')
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{
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/* We have to escape \\ to be able to represent all characters. */
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*wp++ = '\\';
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rp += 1;
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}
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else if (rp[0] == '\\' && rp[1] == '1' && rp[2] == '3' && rp[3] == '4')
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{
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/* \134 is also \\. */
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*wp++ = '\\';
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rp += 3;
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}
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else
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*wp++ = *rp;
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while (*rp++ != '\0');
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return buf;
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}
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/* Read one mount table entry from STREAM. Returns a pointer to storage
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reused on the next call, or null for EOF or error (use feof/ferror to
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check). */
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struct mntent *
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__getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
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{
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char *cp;
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char *head;
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flockfile (stream);
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do
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{
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char *end_ptr;
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if (fgets_unlocked (buffer, bufsiz, stream) == NULL)
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{
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funlockfile (stream);
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return NULL;
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}
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end_ptr = strchr (buffer, '\n');
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if (end_ptr != NULL) /* chop newline */
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*end_ptr = '\0';
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else
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{
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/* Not the whole line was read. Do it now but forget it. */
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char tmp[1024];
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while (fgets_unlocked (tmp, sizeof tmp, stream) != NULL)
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if (strchr (tmp, '\n') != NULL)
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break;
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}
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head = buffer + strspn (buffer, " \t");
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/* skip empty lines and comment lines: */
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}
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while (head[0] == '\0' || head[0] == '#');
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cp = __strsep (&head, " \t");
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mp->mnt_fsname = cp != NULL ? decode_name (cp) : (char *) "";
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if (head)
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head += strspn (head, " \t");
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cp = __strsep (&head, " \t");
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mp->mnt_dir = cp != NULL ? decode_name (cp) : (char *) "";
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if (head)
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head += strspn (head, " \t");
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cp = __strsep (&head, " \t");
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mp->mnt_type = cp != NULL ? decode_name (cp) : (char *) "";
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if (head)
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head += strspn (head, " \t");
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cp = __strsep (&head, " \t");
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mp->mnt_opts = cp != NULL ? decode_name (cp) : (char *) "";
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switch (head ? sscanf (head, " %d %d ", &mp->mnt_freq, &mp->mnt_passno) : 0)
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{
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case 0:
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mp->mnt_freq = 0;
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case 1:
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mp->mnt_passno = 0;
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case 2:
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break;
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}
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funlockfile (stream);
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return mp;
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}
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INTDEF(__getmntent_r)
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weak_alias (__getmntent_r, getmntent_r)
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/* We have to use an encoding for names if they contain spaces or tabs.
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To be able to represent all characters we also have to escape the
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backslash itself. This "function" must be a macro since we use
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`alloca'. */
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#define encode_name(name) \
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do { \
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const char *rp = name; \
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\
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while (*rp != '\0') \
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if (*rp == ' ' || *rp == '\t' || *rp == '\n' || *rp == '\\') \
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break; \
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else \
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++rp; \
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\
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if (*rp != '\0') \
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{ \
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/* In the worst case the length of the string can increase to \
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four times the current length. */ \
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char *wp; \
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\
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rp = name; \
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name = wp = (char *) alloca (strlen (name) * 4 + 1); \
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\
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do \
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if (*rp == ' ') \
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{ \
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*wp++ = '\\'; \
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*wp++ = '0'; \
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*wp++ = '4'; \
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*wp++ = '0'; \
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} \
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else if (*rp == '\t') \
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{ \
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*wp++ = '\\'; \
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*wp++ = '0'; \
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*wp++ = '1'; \
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*wp++ = '1'; \
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} \
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else if (*rp == '\n') \
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{ \
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*wp++ = '\\'; \
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*wp++ = '0'; \
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*wp++ = '1'; \
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*wp++ = '2'; \
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} \
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else if (*rp == '\\') \
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{ \
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*wp++ = '\\'; \
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*wp++ = '\\'; \
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} \
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else \
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*wp++ = *rp; \
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while (*rp++ != '\0'); \
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} \
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} while (0)
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/* Write the mount table entry described by MNT to STREAM.
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Return zero on success, nonzero on failure. */
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int
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__addmntent (FILE *stream, const struct mntent *mnt)
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{
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struct mntent mntcopy = *mnt;
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if (fseek (stream, 0, SEEK_END))
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return 1;
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/* Encode spaces and tabs in the names. */
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encode_name (mntcopy.mnt_fsname);
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encode_name (mntcopy.mnt_dir);
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encode_name (mntcopy.mnt_type);
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encode_name (mntcopy.mnt_opts);
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return (fprintf (stream, "%s %s %s %s %d %d\n",
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mntcopy.mnt_fsname,
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mntcopy.mnt_dir,
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mntcopy.mnt_type,
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mntcopy.mnt_opts,
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mntcopy.mnt_freq,
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mntcopy.mnt_passno) < 0
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|| fflush (stream) != 0);
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}
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weak_alias (__addmntent, addmntent)
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/* Search MNT->mnt_opts for an option matching OPT.
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Returns the address of the substring, or null if none found. */
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char *
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__hasmntopt (const struct mntent *mnt, const char *opt)
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{
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const size_t optlen = strlen (opt);
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char *rest = mnt->mnt_opts, *p;
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while ((p = strstr (rest, opt)) != NULL)
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{
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if ((p == rest || p[-1] == ',')
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&& (p[optlen] == '\0' || p[optlen] == '=' || p[optlen] == ','))
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return p;
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rest = strchr (p, ',');
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if (rest == NULL)
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break;
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++rest;
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}
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return NULL;
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}
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weak_alias (__hasmntopt, hasmntopt)
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