booster: Add fstab parsing support

This commit changes the booster.conf format from a
simple custom format to that of the /etc/fstab.c

See booster_mount(..) for the mount options supported/required
for LD_PRELOADing booster. I'll write a small help doc soon.

This commit also brings in fstab parsing code into libglusterfs
because Darwin libc only supports reading the hardcoded /etc/fstab.

Signed-off-by: Anand V. Avati <avati@amp.gluster.com>

1 files changed, 309 insertions, 0 deletions

diff --git a/libglusterfs/src/glusterfs_fstab.c b/libglusterfs/src/glusterfs_fstab.c
new file mode 100644
index 000000000..b21197b1d
--- /dev/null
+++ b/libglusterfs/src/glusterfs_fstab.c
@@ -0,0 +1,309 @@
+/* Utilities for reading/writing fstab, mtab, etc.
+   Copyright (C) 1995-2000, 2001, 2002, 2003, 2006
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <alloca.h>
+#include <stdio.h>
+#include <stdio_ext.h>
+#include <string.h>
+#include <sys/types.h>
+#include "glusterfs_fstab.h"
+#include <stdlib.h>
+
+/* Prepare to begin reading and/or writing mount table entries from the
+   beginning of FILE.  MODE is as for `fopen'.  */
+glusterfs_fstab_t *
+glusterfs_fstab_init (const char *file, const char *mode)
+{
+  glusterfs_fstab_t *handle = NULL;
+  /* Extend the mode parameter with "c" to disable cancellation in the
+     I/O functions.  */
+  size_t modelen = strlen (mode);
+  char newmode[modelen + 2];
+  memcpy (mempcpy (newmode, mode, modelen), "c", 2);
+
+  handle = calloc (1, sizeof (glusterfs_fstab_t));
+  if (!handle)
+          goto out;
+
+  FILE *result = fopen (file, newmode);
+  if (result != NULL) {
+    /* We do the locking ourselves.  */
+    __fsetlocking (result, FSETLOCKING_BYCALLER);
+    handle->fp = result;
+  } else {
+          free (handle);
+          handle = NULL;
+  }
+
+out:
+
+  return handle;
+}
+
+int
+glusterfs_fstab_close (glusterfs_fstab_t *h)
+{
+  if (!h)
+    return -1;
+
+  if (h->fp)
+    fclose (h->fp);
+
+  return 0;
+}
+
+/* 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 glusterfs_mntent *
+__glusterfs_fstab_getent (FILE *stream, struct glusterfs_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;
+}
+
+struct glusterfs_mntent *
+glusterfs_fstab_getent (glusterfs_fstab_t *h)
+{
+  if (!h)
+    return NULL;
+
+  if (!h->fp)
+    return NULL;
+
+  return __glusterfs_fstab_getent (h->fp, &h->tmpent, h->buf,
+                                   GF_MNTENT_BUFSIZE);
+}
+
+/* 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 == '\\')			      \
+	break;								      \
+      else								      \
+	++rp;								      \
+									      \
+    if (*rp != '\0')							      \
+      {									      \
+	/* In the worst case the length of the string can increase to	      \
+	   founr 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)
+
+
+int
+glusterfs_fstab_addent (glusterfs_fstab_t *h,
+                        const struct glusterfs_mntent *mnt)
+{
+  struct glusterfs_mntent mntcopy = *mnt;
+  if (!h)
+    return -1;
+
+  if (!h->fp)
+    return -1;
+
+  if (fseek (h->fp, 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 (h->fp, "%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 ? 1 : 0);
+}
+
+
+/* Search MNT->mnt_opts for an option matching OPT.
+   Returns the address of the substring, or null if none found.  */
+char *
+glusterfs_fstab_hasoption (const struct glusterfs_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;
+}