NFSv4 gladly accepts and mounts "hostname:path" instead of
"hostname:/path". NFS also accepts other forms for pathname, but it
doesn't use the exact pathname string used for generating /proc/mounts.
This causes mount entry mistmatch between /etc/mtab and /proc/mounts
files. The former will have the exact given pathname string but the
latter will have a modified path name.
Signed-off-by: Malahal Naineni <malahal@xxxxxxxxxx>
---
utils/mount/nfsumount.c | 94 +++++++++++++++++++++++++++++++++++++++++-----
1 files changed, 83 insertions(+), 11 deletions(-)
diff --git a/utils/mount/nfsumount.c b/utils/mount/nfsumount.c
index 3538d88..54542a5 100644
--- a/utils/mount/nfsumount.c
+++ b/utils/mount/nfsumount.c
@@ -139,6 +139,88 @@ static int del_mtab(const char *spec, const char *node)
return EX_FILEIO;
}
+/*
+ * Return normalized path.
+ *
+ * Resolve "." and ".." components. Replace multiple slashes with one
+ * slash. realpath is close but doesn't work for us as the path won't
+ * exist on the client.
+ *
+ * The return string must be freed by the caller.
+ */
+static char *normpath(const char *path)
+{
+ const char *ptr, *next, *end;
+ char *norm; /* result */
+
+ if (!path)
+ return NULL;
+
+ norm = malloc(strlen(path)+1);
+ if (!norm)
+ return NULL;
+
+ end = path+strlen(path);
+ *norm = '\0'; /* Make it a NULL string */
+ for (ptr = path; ptr < end; ptr = next+1) {
+ next = strchr(ptr, '/');
+ if (!next)
+ next = end;
+ int pclen = next - ptr; /* path component length */
+ if (strncmp(ptr, ".", pclen) == 0)
+ continue;
+ if (strncmp(ptr, "..", pclen) == 0) {
+ char *tmp = strrchr(norm, '/');
+ if (tmp)
+ *tmp = '\0';
+ continue;
+ }
+
+ /* Add the new component */
+ strncat(norm, "/", 1);
+ strncat(norm, ptr, pclen);
+ }
+
+ /*
+ * If there was no component to copy, norm would be null.
+ * Return "/" in that case
+ */
+ if (*norm == '\0')
+ strcpy(norm, "/");
+
+ return norm;
+}
+
+/*
+ * Detect if the given two entries refer to the same mount entry.
+ * Usually one entry is from /etc/mtab and the other is from
+ * /proc/mounts.
+ */
+static int nfs_same_mount_entry(const struct mntentchn *mc1,
+ const struct mntentchn *mc2)
+{
+ char *host1, *host2;
+ char *path1, *path2;
+ char *norm1, *norm2;
+ int retval;
+
+ nfs_parse_devname(mc1->m.mnt_fsname, &host1, &path1);
+ nfs_parse_devname(mc2->m.mnt_fsname, &host2, &path2);
+ norm1 = normpath(path1);
+ norm2 = normpath(path2);
+
+ retval = strcmp(host1, host2) == 0 && strcmp(norm1, norm2) == 0;
+
+ free(host1);
+ free(host2);
+ free(path1);
+ free(path2);
+ free(norm1);
+ free(norm2);
+
+ return retval;
+}
+
/*
* Detect NFSv4 mounts.
*
@@ -161,17 +243,7 @@ static int nfs_umount_is_vers4(const struct mntentchn *mc)
goto not_found;
do {
- size_t 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)
+ if (!nfs_same_mount_entry(pmc, mc))
continue;
if (strcmp(pmc->m.mnt_type, "nfs4") == 0)
--
1.7.8.3
--
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