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-rw-r--r--conf/mtab/mtab_mach3.c501
1 files changed, 501 insertions, 0 deletions
diff --git a/conf/mtab/mtab_mach3.c b/conf/mtab/mtab_mach3.c
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index 000000000000..af1313d3d8da
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+++ b/conf/mtab/mtab_mach3.c
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+/*
+ * Copyright (c) 1997-2014 Erez Zadok
+ * Copyright (c) 1990 Jan-Simon Pendry
+ * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Jan-Simon Pendry at Imperial College, London.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *
+ * File: am-utils/conf/mtab/mtab_mach3.c
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif /* HAVE_CONFIG_H */
+#include <am_defs.h>
+#include <amu.h>
+
+#define NFILE_RETRIES 10 /* number of retries (seconds) */
+
+static FILE *mnt_file;
+
+
+/*
+ * If the system is being trashed by something, then
+ * opening mtab may fail with ENFILE. So, go to sleep
+ * for a second and try again. (Yes - this has happened to me.)
+ *
+ * Note that this *may* block the automounter, oh well.
+ * If we get to this state then things are badly wrong anyway...
+ *
+ * Give the system 10 seconds to recover but then give up.
+ * Hopefully something else will exit and free up some file
+ * table slots in that time.
+ */
+#ifdef HAVE_FCNTL_H
+static int
+lock(int fd)
+{
+ int rc;
+ struct flock lk;
+
+ lk.l_type = F_WRLCK;
+ lk.l_whence = 0;
+ lk.l_start = 0;
+ lk.l_len = 0;
+
+again:
+ rc = fcntl(fd, F_SETLKW, (caddr_t) & lk);
+ if (rc < 0 && (errno == EACCES || errno == EAGAIN)) {
+# ifdef DEBUG
+ dlog("Blocked, trying to obtain exclusive mtab lock");
+# endif /* DEBUG */
+ sleep(1);
+ goto again;
+ }
+ return rc;
+}
+#else /* not HAVE_FCNTL_H */
+# define lock(fd) (flock((fd), LOCK_EX))
+#endif /* not HAVE_FCNTL_H */
+
+
+static FILE *
+open_locked_mtab(char *mnttabname, char *mode, char *fs)
+{
+ FILE *mfp = NULL;
+
+ /*
+ * There is a possible race condition if two processes enter
+ * this routine at the same time. One will be blocked by the
+ * exclusive lock below (or by the shared lock in setmntent)
+ * and by the time the second process has the exclusive lock
+ * it will be on the wrong underlying object. To check for this
+ * the mtab file is stat'ed before and after all the locking
+ * sequence, and if it is a different file then we assume that
+ * it may be the wrong file (only "may", since there is another
+ * race between the initial stat and the setmntent).
+ *
+ * Simpler solutions to this problem are invited...
+ */
+ int racing = 2;
+ int rc;
+ int retries = 0;
+ struct stat st_before, st_after;
+
+ if (mnt_file) {
+#ifdef DEBUG
+ dlog("Forced close on %s in read_mtab", mnttabname);
+#endif /* DEBUG */
+ endmntent(mnt_file);
+ mnt_file = NULL;
+ }
+again:
+ if (mfp) {
+ endmntent(mfp);
+ mfp = NULL;
+ }
+ if (stat(mnttabname, &st_before) < 0) {
+ plog(XLOG_ERROR, "%s: stat: %m", mnttabname);
+ if (errno == ESTALE) {
+ /* happens occasionally */
+ sleep(1);
+ goto again;
+ }
+ /*
+ * If 'mnttabname' file does not exist give setmntent() a
+ * chance to create it (depending on the mode).
+ * Otherwise, bail out.
+ */
+ else if (errno != ENOENT) {
+ return 0;
+ }
+ }
+eacces:
+ mfp = setmntent(mnttabname, mode);
+ if (!mfp) {
+ /*
+ * Since setmntent locks the descriptor, it
+ * is possible it can fail... so retry if
+ * needed.
+ */
+ if (errno == EACCES || errno == EAGAIN) {
+#ifdef DEBUG
+ dlog("Blocked, trying to obtain exclusive mtab lock");
+#endif /* DEBUG */
+ goto eacces;
+ } else if (errno == ENFILE && retries++ < NFILE_RETRIES) {
+ sleep(1);
+ goto eacces;
+ }
+ plog(XLOG_ERROR, "setmntent(\"%s\", \"%s\"): %m", mnttabname, mode);
+ return 0;
+ }
+ /*
+ * At this point we have an exclusive lock on the mount list,
+ * but it may be the wrong one so...
+ */
+
+ /*
+ * Need to get an exclusive lock on the current
+ * mount table until we have a new copy written
+ * out, when the lock is released in free_mntlist.
+ * flock is good enough since the mount table is
+ * not shared between machines.
+ */
+ do
+ rc = lock(fileno(mfp));
+ while (rc < 0 && errno == EINTR);
+ if (rc < 0) {
+ plog(XLOG_ERROR, "Couldn't lock %s: %m", mnttabname);
+ endmntent(mfp);
+ return 0;
+ }
+ /*
+ * Now check whether the mtab file has changed under our feet
+ */
+ if (stat(mnttabname, &st_after) < 0) {
+ plog(XLOG_ERROR, "%s: stat", mnttabname);
+ goto again;
+ }
+ if (st_before.st_dev != st_after.st_dev ||
+ st_before.st_ino != st_after.st_ino) {
+ struct timeval tv;
+ if (racing == 0) {
+ /* Sometimes print a warning */
+ plog(XLOG_WARNING,
+ "Possible mount table race - retrying %s", fs);
+ }
+ racing = (racing + 1) & 3;
+ /*
+ * Take a nap. From: Doug Kingston <dpk@morgan.com>
+ */
+ tv.tv_sec = 0;
+ tv.tv_usec = (am_mypid & 0x07) << 17;
+ if (tv.tv_usec)
+ if (select(0, (voidp) 0, (voidp) 0, (voidp) 0, &tv) < 0)
+ plog(XLOG_WARNING, "mtab nap failed: %m");
+
+ goto again;
+ }
+ return mfp;
+}
+
+
+/*
+ * Unlock the mount table
+ */
+void
+unlock_mntlist(void)
+{
+ /*
+ * Release file lock, by closing the file
+ */
+ if (mnt_file) {
+ dlog("unlock_mntlist: releasing");
+ endmntent(mnt_file);
+ mnt_file = NULL;
+ }
+}
+
+
+/*
+ * routine to convert notation "/@honeydew" to the notation
+ * honeydew:/ and vice versa (honeydew:/ to /@honeydew)
+ * This lets you put /@honeydew in /etc/fstab without changing
+ * fstab.c and it lets you use EITHER notation on the command line!
+ */
+static char *
+convert(register char *s, char bad, char good)
+{
+ char *index();
+ register char *t, *p;
+ register int len1, len2, i;
+ char *ptr;
+
+ if ((p = index(s, bad)) == NULL) {
+ return (s);
+ }
+ ptr = t = (char *) xzalloc(MAXPATHLEN * sizeof(char));
+ len1 = p - s;
+ len2 = strlen(s) - len1 - 1;
+ p++;
+ for (i = 0; i < len2; i++)
+ *t++ = p[i];
+ *t++ = good;
+ for (i = 0; i < len1; i++)
+ *t++ = s[i];
+ return (ptr);
+}
+
+
+static
+mntprtent3(FILE *mnttabp, register mntent_t *mnt)
+{
+ char *cvtd = convert(mnt->mnt_fsname, ':', '@');
+
+ dlog("%x:%s:%s:%s:%d:%d:%s:%s:\n",
+ mnttabp,
+ (cvtd ? cvtd : ""),
+ (mnt->mnt_dir ? mnt->mnt_dir : ""),
+ (mnt->mnt_opts ? mnt->mnt_opts : ""),
+ mnt->mnt_freq,
+ mnt->mnt_passno,
+ (mnt->mnt_type ? mnt->mnt_type : ""),
+ (mnt->mnt_opts2 ? mnt->mnt_opts2 : "")
+ );
+ fprintf(mnttabp, "%s:%s:%s:%d:%d:%s:%s:\n",
+ (cvtd ? cvtd : ""),
+ (mnt->mnt_dir ? mnt->mnt_dir : ""),
+ (mnt->mnt_opts ? mnt->mnt_opts : ""),
+ mnt->mnt_freq,
+ mnt->mnt_passno,
+ (mnt->mnt_type ? mnt->mnt_type : ""),
+ (mnt->mnt_opts2 ? mnt->mnt_opts2 : "")
+ );
+ XFREE(cvtd);
+ cvtd = NULL;
+ return (0);
+}
+
+
+addmntent3(FILE *mnttabp, register mntent_t *mnt)
+{
+ if (fseek(mnttabp, 0, 2) < 0) {
+ return (1);
+ }
+ mntprtent3(mnttabp, mnt);
+ return (0);
+}
+
+
+/*
+ * Write out a mount list
+ */
+void
+rewrite_mtab(mntlist *mp, const char *mnttabname)
+{
+ FILE *mfp;
+ int error = 0;
+ /*
+ * Concoct a temporary name in the same directory as the target mount
+ * table so that rename() will work.
+ */
+ char tmpname[64];
+ int retries;
+ int tmpfd;
+ char *cp;
+ char *mcp = mnttabname;
+
+ cp = strrchr(mcp, '/');
+ if (cp) {
+ memmove(tmpname, mcp, cp - mcp);
+ tmpname[cp - mcp] = '\0';
+ } else {
+ plog(XLOG_WARNING, "No '/' in mtab (%s), using \".\" as tmp directory", mnttabname);
+ tmpname[0] = '.';
+ tmpname[1] = '\0';
+ }
+ xstrlcat(tmpname, "/mtabXXXXXX", sizeof(tmpname));
+ retries = 0;
+enfile1:
+#ifdef HAVE_MKSTEMP
+ tmpfd = mkstemp(tmpname);
+ fchmod(tmpfd, 0644);
+#else /* not HAVE_MKSTEMP */
+ mktemp(tmpname);
+ tmpfd = open(tmpname, O_RDWR | O_CREAT | O_TRUNC, 0644);
+#endif /* not HAVE_MKSTEMP */
+ if (tmpfd < 0) {
+ if (errno == ENFILE && retries++ < NFILE_RETRIES) {
+ sleep(1);
+ goto enfile1;
+ }
+ plog(XLOG_ERROR, "%s: open: %m", tmpname);
+ return;
+ }
+ if (close(tmpfd) < 0)
+ plog(XLOG_ERROR, "Couldn't close tmp file descriptor: %m");
+
+ retries = 0;
+enfile2:
+ mfp = setmntent(tmpname, "w");
+ if (!mfp) {
+ if (errno == ENFILE && retries++ < NFILE_RETRIES) {
+ sleep(1);
+ goto enfile2;
+ }
+ plog(XLOG_ERROR, "setmntent(\"%s\", \"w\"): %m", tmpname);
+ error = 1;
+ goto out;
+ }
+ while (mp) {
+ if (mp->mnt) {
+ if (addmntent3(mfp, mp->mnt)) {
+ plog(XLOG_ERROR, "Can't write entry to %s", tmpname);
+ error = 1;
+ goto out;
+ }
+ }
+ mp = mp->mnext;
+ }
+
+ /*
+ * SunOS 4.1 manuals say that the return code from endmntent()
+ * is always 1 and to treat as a void. That means we need to
+ * call fflush() to make sure the new mtab file got written.
+ */
+ if (fflush(mfp)) {
+ plog(XLOG_ERROR, "flush new mtab file: %m");
+ error = 1;
+ goto out;
+ }
+ (void) endmntent(mfp);
+
+ /*
+ * Rename temporary mtab to real mtab
+ */
+ if (rename(tmpname, mnttabname) < 0) {
+ plog(XLOG_ERROR, "rename %s to %s: %m", tmpname, mnttabname);
+ error = 1;
+ goto out;
+ }
+out:
+ if (error)
+ (void) unlink(tmpname);
+}
+
+
+static void
+mtab_stripnl(char *s)
+{
+ do {
+ s = strchr(s, '\n');
+ if (s)
+ *s++ = ' ';
+ } while (s);
+}
+
+
+/*
+ * Append a mntent structure to the
+ * current mount table.
+ */
+void
+write_mntent(mntent_t *mp, const char *mnttabname)
+{
+ int retries = 0;
+ FILE *mfp;
+enfile:
+ mfp = open_locked_mtab(mnttabname, "a", mp->mnt_dir);
+ if (mfp) {
+ mtab_stripnl(mp->mnt_opts);
+ if (addmntent3(mfp, mp))
+ plog(XLOG_ERROR, "Couldn't write %s: %m", mnttabname);
+ if (fflush(mfp))
+ plog(XLOG_ERROR, "Couldn't flush %s: %m", mnttabname);
+ (void) endmntent(mfp);
+ } else {
+ if (errno == ENFILE && retries < NFILE_RETRIES) {
+ sleep(1);
+ goto enfile;
+ }
+ plog(XLOG_ERROR, "setmntent(\"%s\", \"a\"): %m", mnttabname);
+ }
+}
+
+
+static mntent_t *
+mnt_dup(mntent_t *mp)
+{
+ mntent_t *new_mp = ALLOC(mntent_t);
+
+ new_mp->mnt_fsname = convert(mp->mnt_fsname, '@', ':');
+
+ new_mp->mnt_dir = xstrdup(mp->mnt_dir);
+ new_mp->mnt_type = xstrdup(mp->mnt_type);
+ new_mp->mnt_opts = xstrdup(mp->mnt_opts);
+
+ new_mp->mnt_freq = mp->mnt_freq;
+ new_mp->mnt_passno = mp->mnt_passno;
+
+ return new_mp;
+}
+
+
+/*
+ * Read a mount table into memory
+ */
+mntlist *
+read_mtab(char *fs, const char *mnttabname)
+{
+ mntlist **mpp, *mhp;
+
+ mntent_t *mep;
+ FILE *mfp = open_locked_mtab(mnttabname, "r+", fs);
+
+ if (!mfp)
+ return 0;
+
+ mpp = &mhp;
+
+/*
+ * XXX - In SunOS 4 there is (yet another) memory leak
+ * which loses 1K the first time getmntent is called.
+ * (jsp)
+ */
+ while (mep = getmntent(mfp)) {
+ /*
+ * Allocate a new slot
+ */
+ *mpp = ALLOC(struct mntlist);
+
+ /*
+ * Copy the data returned by getmntent
+ */
+ (*mpp)->mnt = mnt_dup(mep);
+
+ /*
+ * Move to next pointer
+ */
+ mpp = &(*mpp)->mnext;
+ }
+ *mpp = NULL;
+
+ /*
+ * If we are not updating the mount table then we
+ * can free the resources held here, otherwise they
+ * must be held until the mount table update is complete
+ */
+ mnt_file = mfp;
+
+ return mhp;
+}