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-rw-r--r--conf/mtab/mtab_svr4.c302
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diff --git a/conf/mtab/mtab_svr4.c b/conf/mtab/mtab_svr4.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_svr4.c
+ *
+ * How to manage the mount table file. Based on other SVR3 ports.
+ * -Erez Zadok <ezk@cs.columbia.edu>
+ */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif /* HAVE_CONFIG_H */
+#include <am_defs.h>
+#include <amu.h>
+
+/*
+ * file descriptor for lock file
+ * values: -1 no file-descriptor was set yet (or mnttab unlocked, or error
+ * in locking).
+ * >=0 legal file-descriptor value (file lock succeeded)
+ */
+static int mntent_lock_fd = -1;
+
+
+#ifdef MOUNT_TABLE_ON_FILE
+static char mtlckname[] = "/etc/.mnttab.lock";
+#endif /* MOUNT_TABLE_ON_FILE */
+
+
+/****************************************************************************/
+/*** Private functions */
+/****************************************************************************/
+
+static void
+unlockmnttab(void)
+{
+#ifdef MOUNT_TABLE_ON_FILE
+ if (mntent_lock_fd >= 0) {
+ close(mntent_lock_fd);
+ mntent_lock_fd = -1;
+ }
+#endif /* MOUNT_TABLE_ON_FILE */
+}
+
+
+#ifdef MOUNT_TABLE_ON_FILE
+static int
+lockfile(int fd, int type)
+{
+ struct flock lk;
+ int ret;
+
+ lk.l_type = type;
+ lk.l_whence = 0;
+ lk.l_start = 0;
+ lk.l_len = 0;
+
+ /*
+ * F_SETLKW means to block until the read or write block is free to be
+ * locked.
+ */
+ ret = fcntl(fd, F_SETLKW, &lk);
+ return ret;
+}
+#endif /* MOUNT_TABLE_ON_FILE */
+
+
+/* return 0 if locking succeeded, -1 if failed */
+static int
+lockmnttab(void)
+{
+#ifdef MOUNT_TABLE_ON_FILE
+ /* if mnttab file is locked, all is well */
+ if (mntent_lock_fd >= 0)
+ return 0;
+
+ /* need to lock mnttab file. first, open the file */
+ mntent_lock_fd = open(mtlckname, O_RDWR | O_CREAT, 0600);
+ if (mntent_lock_fd < 0) {
+ plog(XLOG_ERROR, "Unable to open/creat %s: %m", mtlckname);
+ return -1;
+ }
+
+ /* if succeeded in opening the file, try to lock it */
+ if (lockfile(mntent_lock_fd, F_WRLCK) < 0) {
+ close(mntent_lock_fd);
+ mntent_lock_fd = -1;
+#ifdef DEBUG
+ dlog("lock %s failed: %m", mtlckname);
+#endif /* DEBUG */
+ return -1;
+ }
+#else /* not MOUNT_TABLE_ON_FILE */
+ /* fake lock for in-kernel mount table */
+#endif /* not MOUNT_TABLE_ON_FILE */
+
+ /* finally, succeeded in also locking the file */
+ return 0;
+}
+
+
+/*
+ * Convert from solaris mnttab to Amd mntent. Since am-utils uses
+ * native "struct mnttab" if available, this really copies fields of
+ * the same structure.
+ */
+static mntent_t *
+mnt_dup(const mntent_t *mtp)
+{
+ mntent_t *mep = ALLOC(mntent_t);
+
+ mep->mnt_fsname = xstrdup(mtp->mnt_fsname);
+ mep->mnt_dir = xstrdup(mtp->mnt_dir);
+ mep->mnt_type = xstrdup(mtp->mnt_type);
+ mep->mnt_opts = xstrdup(mtp->mnt_opts);
+ mep->mnt_time = xstrdup(mtp->mnt_time);
+
+ return mep;
+}
+
+
+/*
+ * Adjust arguments in mntent_t.
+ */
+#ifdef MOUNT_TABLE_ON_FILE
+static mntent_t *
+update_mnttab_fields(const mntent_t *mnt)
+{
+ static mntent_t mt;
+ static char timestr[16];
+ struct timeval tv;
+
+ /* most fields don't change, only update mnt_time below */
+ mt.mnt_fsname = mnt->mnt_fsname;
+ mt.mnt_dir = mnt->mnt_dir;
+ mt.mnt_type = mnt->mnt_type;
+ mt.mnt_opts = mnt->mnt_opts;
+
+ /*
+ * Solaris 2.5 and newer take a second argument to gettimeofday(). If you
+ * find a useful svr4-like OS that uses the old style, and this code here
+ * fails, then create a new autoconf test that will determine the number
+ * of arguments gettimeofday() takes. -Erez.
+ */
+ if (gettimeofday(&tv, NULL) < 0)
+ timestr[0] = '\0';
+ else
+ xsnprintf(timestr, sizeof(timestr), "%ld", tv.tv_sec);
+
+ mt.mnt_time = timestr;
+
+ return &mt;
+}
+#endif /* MOUNT_TABLE_ON_FILE */
+
+
+static void
+write_mntent_to_mtab(FILE *fp, const mntent_t *mnt)
+{
+#ifdef MOUNT_TABLE_ON_FILE
+ putmntent(fp, update_mnttab_fields(mnt));
+#endif /* MOUNT_TABLE_ON_FILE */
+}
+
+
+/****************************************************************************/
+/*** Public functions */
+/****************************************************************************/
+
+
+void
+unlock_mntlist(void)
+{
+ unlockmnttab();
+}
+
+
+/*
+ * Read a mount table into memory
+ */
+mntlist *
+read_mtab(char *fs, const char *mnttabname)
+{
+ mntlist **mpp, *mhp;
+ FILE *fp;
+ mntent_t mountbuf;
+ int ret;
+
+ if (lockmnttab() < 0) /* failed locking */
+ return NULL;
+
+ fp = fopen(mnttabname, "r");
+ if (fp == NULL) {
+ plog(XLOG_ERROR, "Can't open %s: %m", mnttabname);
+ return NULL;
+ }
+ mpp = &mhp;
+
+ while ((ret = getmntent(fp, &mountbuf)) == 0) {
+ /*
+ * Allocate a new slot
+ */
+ *mpp = ALLOC(struct mntlist);
+
+ /*
+ * Copy the data returned by getmntent
+ */
+ (*mpp)->mnt = mnt_dup(&mountbuf);
+
+ /*
+ * Move to next pointer
+ */
+ mpp = &(*mpp)->mnext;
+ }
+
+ if (ret > 0) {
+ plog(XLOG_ERROR, "read error on %s: %m", mnttabname);
+ unlockmnttab();
+ mhp = NULL;
+ }
+ *mpp = NULL;
+
+ fclose(fp);
+ return mhp;
+}
+
+
+void
+rewrite_mtab(mntlist *mp, const char *mnttabname)
+{
+ FILE *fp;
+
+ assert(mntent_lock_fd >= 0); /* ensure lock fd is valid */
+
+ fp = fopen(mnttabname, "r+");
+ if (fp == NULL) {
+ plog(XLOG_ERROR, "Can't open %s: %m", mnttabname);
+ unlockmnttab();
+ return;
+ }
+ while (mp) {
+ if (mp->mnt)
+ write_mntent_to_mtab(fp, mp->mnt);
+ mp = mp->mnext;
+ }
+
+ ftruncate(fileno(fp), ftell(fp));
+ fclose(fp);
+ unlockmnttab();
+}
+
+
+void
+write_mntent(mntent_t *mtp, const char *mnttabname)
+{
+ FILE *fp;
+
+ if (lockmnttab() < 0)
+ return;
+
+ fp = fopen(mnttabname, "a");
+ if (fp == NULL) {
+ plog(XLOG_ERROR, "Unable to append %s: %m", mnttabname);
+ return;
+ }
+ write_mntent_to_mtab(fp, mtp);
+
+ fclose(fp);
+ unlockmnttab();
+}
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