umount.nfs: fix nfs4 check

From: Ian Kent <ikent@redhat.com>

nfs_umount_is_vers4() doesn't take acount of the escaping of characters
seen in /proc/mounts and /etc/mtab as the functions in fstab.c do. This
leads to an inability to umount a mount containing any of these escaped
characters (like spaces).

This patch changes nfs_umount_is_vers4() to use functions in fstab.c and
adds a function to fstab.c to read /proc/mounts specifically, as it was
used  for the check in nfs_umount_is_vers4() previously.

Signed-off-by: Ian Kent <ikent@redhat.com>
Signed-off-by: Steve Dickson <steved@redhat.com>

3 files changed, 84 insertions, 44 deletions

diff --git a/utils/mount/fstab.c b/utils/mount/fstab.c
index 1fc9efe..eedbdda 100644
--- a/utils/mount/fstab.c
+++ b/utils/mount/fstab.c
@@ -86,10 +86,13 @@ mtab_is_writable() {
 
 struct mntentchn mounttable;
 static int got_mtab = 0;
+struct mntentchn procmounts;
+static int got_procmounts = 0;
 struct mntentchn fstab;
 static int got_fstab = 0;
 
 static void read_mounttable(void);
+static void read_procmounts(void);
 static void read_fstab(void);
 
 static struct mntentchn *
@@ -101,6 +104,14 @@ mtab_head(void)
 }
 
 static struct mntentchn *
+procmounts_head(void)
+{
+	if (!got_procmounts)
+		read_procmounts();
+	return &procmounts;
+}
+
+static struct mntentchn *
 fstab_head(void)
 {
 	if (!got_fstab)
@@ -186,6 +197,30 @@ read_mounttable() {
         read_mntentchn(mfp, fnam, mc);
 }
 
+/*
+ * Read /proc/mounts.
+ * This produces a linked list. The list head procmounts is a dummy.
+ * Return 0 on success.
+ */
+static void
+read_procmounts() {
+        mntFILE *mfp;
+        const char *fnam;
+        struct mntentchn *mc = &procmounts;
+
+        got_procmounts = 1;
+        mc->nxt = mc->prev = NULL;
+
+        fnam = PROC_MOUNTS;
+        mfp = nfs_setmntent(fnam, "r");
+        if (mfp == NULL || mfp->mntent_fp == NULL) {
+                nfs_error(_("warning: can't open %s: %s"),
+                          PROC_MOUNTS, strerror (errno));
+                return;
+        }
+        read_mntentchn(mfp, fnam, mc);
+}
+
 static void
 read_fstab()
 {
@@ -225,6 +260,23 @@ getmntdirbackward (const char *name, struct mntentchn *mcprev) {
 }
 
 /*
+ * Given the directory name NAME, and the place MCPREV we found it last time,
+ * try to find more occurrences.
+ */
+struct mntentchn *
+getprocmntdirbackward (const char *name, struct mntentchn *mcprev) {
+	struct mntentchn *mc, *mc0;
+
+	mc0 = procmounts_head();
+	if (!mcprev)
+		mcprev = mc0;
+	for (mc = mcprev->prev; mc && mc != mc0; mc = mc->prev)
+		if (streq(mc->m.mnt_dir, name))
+			return mc;
+	return NULL;
+}
+
+/*
  * Given the device name NAME, and the place MCPREV we found it last time,
  * try to find more occurrences.
  */ 
diff --git a/utils/mount/fstab.h b/utils/mount/fstab.h
index dc7c9fc..313bf9b 100644
--- a/utils/mount/fstab.h
+++ b/utils/mount/fstab.h
@@ -18,6 +18,7 @@ struct mntentchn {
 
 struct mntentchn *getmntoptfile (const char *file);
 struct mntentchn *getmntdirbackward (const char *dir, struct mntentchn *mc);
+struct mntentchn *getprocmntdirbackward (const char *name, struct mntentchn *mc);
 struct mntentchn *getmntdevbackward (const char *dev, struct mntentchn *mc);
 
 struct mntentchn *getfsfile (const char *file);
diff --git a/utils/mount/nfsumount.c b/utils/mount/nfsumount.c
index 8cd2852..b846564 100644
--- a/utils/mount/nfsumount.c
+++ b/utils/mount/nfsumount.c
@@ -151,65 +151,50 @@ static int del_mtab(const char *spec, const char *node)
  */
 static int nfs_umount_is_vers4(const struct mntentchn *mc)
 {
-	char buffer[LINELEN], *next;
+	struct mntentchn *pmc;
+	struct mount_options *options;
 	int retval;
-	FILE *f;
-
-	if ((f = fopen(MOUNTSFILE, "r")) == NULL) {
-		fprintf(stderr, "%s: %s\n",
-			MOUNTSFILE, strerror(errno));
-		return -1;
-	}
 
 	retval = -1;
-	while (fgets(buffer, sizeof(buffer), f) != NULL) {
-		char *device, *mntdir, *type, *flags;
-		struct mount_options *options;
-		char *line = buffer;
-
-		next = strchr(line, '\n');
-		if (next != NULL)
-			*next = '\0';
-
-		device = strtok(line, " \t");
-		if (device == NULL)
-			continue;
-		mntdir = strtok(NULL, " \t");
-		if (mntdir == NULL)
-			continue;
-		if (strcmp(device, mc->m.mnt_fsname) != 0 &&
-		    strcmp(mntdir, mc->m.mnt_dir) != 0)
+	pmc = getprocmntdirbackward(mc->m.mnt_dir, NULL);
+	if (!pmc)
+		goto not_found;
+
+	do {
+		int nlen = strlen(pmc->m.mnt_fsname);
+		/*
+		 * It's possible the mount location string in /proc/mounts
+		 * ends with a '/'. In this case, if the entry came from
+		 * /etc/mtab, it won't have the trailing '/' so deal with
+		 * it.
+		 */
+		while (pmc->m.mnt_fsname[nlen - 1] == '/')
+			nlen--;
+		if (strncmp(pmc->m.mnt_fsname, mc->m.mnt_fsname, nlen) != 0)
 			continue;
 
-		type = strtok(NULL, " \t");
-		if (type == NULL)
-			continue;
-		if (strcmp(type, "nfs4") == 0)
+		if (strcmp(pmc->m.mnt_type, "nfs4") == 0)
 			goto out_nfs4;
 
-		flags = strtok(NULL, " \t");
-		if (flags == NULL)
-			continue;
-		options = po_split(flags);
+		options = po_split(pmc->m.mnt_opts);
 		if (options != NULL) {
 			unsigned long version;
-			int rc;
-
-			rc = nfs_nfs_version(options, &version);
+			int rc = nfs_nfs_version(options, &version);
 			po_destroy(options);
 			if (rc && version == 4)
 				goto out_nfs4;
 		}
 
-		goto out_nfs;
-	}
-	if (retval == -1)
+		if (strcmp(pmc->m.mnt_type, "nfs") == 0)
+			goto out_nfs;
+	} while ((pmc = getprocmntdirbackward(mc->m.mnt_dir, pmc)) != NULL);
+
+	if (retval == -1) {
+not_found:
 		fprintf(stderr, "%s was not found in %s\n",
 			mc->m.mnt_dir, MOUNTSFILE);
-
-out:
-	fclose(f);
-	return retval;
+		goto out;
+	}
 
 out_nfs4:
 	if (verbose)
@@ -221,7 +206,9 @@ out_nfs:
 	if (verbose)
 		fprintf(stderr, "Legacy NFS mount point detected\n");
 	retval = 0;
-	goto out;
+
+out:
+	return retval;
 }
 
 static struct option umount_longopts[] =