[klibc] [PATCH 3/3] kinit: Parse mount command options properly.
Curt Wohlgemuth
curtw at google.com
Thu Mar 8 15:11:32 PST 2012
Mount options sent via "kinit_mount=" command line args, or
an embedded fstab file, were not parsed properly to turn
option strings into mount flags where possible.
Stole and modified code from
usr/utils/mount_opts.c
to handle this.
Tested: Tested using a variety of command line and fstab
mounts and options.
Signed-off-by: Curt Wohlgemuth <curtw at google.com>
---
usr/kinit/do_mounts.c | 192 +++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 164 insertions(+), 28 deletions(-)
diff --git a/usr/kinit/do_mounts.c b/usr/kinit/do_mounts.c
index d12b07a..b648299 100644
--- a/usr/kinit/do_mounts.c
+++ b/usr/kinit/do_mounts.c
@@ -14,6 +14,148 @@
#include "fstype.h"
#include "zlib.h"
+#ifndef MS_RELATIME
+# define MS_RELATIME (1<<21) /* Update atime relative to mtime/ctime. */
+#endif
+
+#ifndef MS_STRICTATIME
+# define MS_STRICTATIME (1<<24) /* Always perform atime updates */
+#endif
+
+/*
+ * The following mount option parsing was stolen from
+ *
+ * usr/utils/mount_opts.c
+ *
+ * and adapted to add some later mount flags.
+ */
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof(x[0]))
+
+struct mount_opts {
+ const char str[16];
+ unsigned long rwmask;
+ unsigned long rwset;
+ unsigned long rwnoset;
+};
+
+struct extra_opts {
+ char *str;
+ char *end;
+ int used_size;
+ int alloc_size;
+};
+
+/*
+ * These options define the function of "mount(2)".
+ */
+#define MS_TYPE (MS_REMOUNT|MS_BIND|MS_MOVE)
+
+
+/* These must be in alphabetic order! */
+static const struct mount_opts options[] = {
+ /* name mask set noset */
+ {"async", MS_SYNCHRONOUS, 0, MS_SYNCHRONOUS},
+ {"atime", MS_NOATIME, 0, MS_NOATIME},
+ {"bind", MS_TYPE, MS_BIND, 0,},
+ {"dev", MS_NODEV, 0, MS_NODEV},
+ {"diratime", MS_NODIRATIME, 0, MS_NODIRATIME},
+ {"dirsync", MS_DIRSYNC, MS_DIRSYNC, 0},
+ {"exec", MS_NOEXEC, 0, MS_NOEXEC},
+ {"move", MS_TYPE, MS_MOVE, 0},
+ {"nodev", MS_NODEV, MS_NODEV, 0},
+ {"noexec", MS_NOEXEC, MS_NOEXEC, 0},
+ {"nosuid", MS_NOSUID, MS_NOSUID, 0},
+ {"recurse", MS_REC, MS_REC, 0},
+ {"relatime", MS_RELATIME, MS_RELATIME, 0},
+ {"remount", MS_TYPE, MS_REMOUNT, 0},
+ {"ro", MS_RDONLY, MS_RDONLY, 0},
+ {"rw", MS_RDONLY, 0, MS_RDONLY},
+ {"strictatime", MS_STRICTATIME, MS_STRICTATIME, 0},
+ {"suid", MS_NOSUID, 0, MS_NOSUID},
+ {"sync", MS_SYNCHRONOUS, MS_SYNCHRONOUS, 0},
+ {"verbose", MS_VERBOSE, MS_VERBOSE, 0},
+};
+
+/*
+ * Append 's' to 'extra->str'. 's' is a mount option that can't be turned into
+ * a flag. Return 0 on success, -1 on error.
+ */
+static int add_extra_option(struct extra_opts *extra, char *s)
+{
+ int len = strlen(s);
+ int newlen = extra->used_size + len;
+
+ if (extra->str)
+ len++; /* +1 for ',' */
+
+ if (newlen >= extra->alloc_size) {
+ char *new;
+
+ new = realloc(extra->str, newlen + 1); /* +1 for NUL */
+ if (!new) {
+ if (extra->str)
+ free(extra->str);
+ return -1;
+ }
+
+ extra->str = new;
+ extra->end = extra->str + extra->used_size;
+ extra->alloc_size = newlen;
+ }
+
+ if (extra->used_size) {
+ *extra->end = ',';
+ extra->end++;
+ }
+ strcpy(extra->end, s);
+ extra->used_size += len;
+
+ return 0;
+}
+
+/*
+ * Parse the options in 'arg'; put numeric mount flags into 'flags' and
+ * the rest into 'extra'. Return 0 on success, -1 on error.
+ */
+static int
+parse_mount_options(char *arg, unsigned long *flags, struct extra_opts *extra)
+{
+ char *s;
+
+ while ((s = strsep(&arg, ",")) != NULL) {
+ char *opt = s;
+ unsigned int i;
+ int res;
+ int no = (s[0] == 'n' && s[1] == 'o');
+ int found = 0;
+
+ if (no)
+ s += 2;
+
+ for (i = 0; i < ARRAY_SIZE(options); i++) {
+
+ res = strcmp(s, options[i].str);
+ if (res == 0) {
+ found = 1;
+ *flags &= ~options[i].rwmask;
+ if (no)
+ *flags |= options[i].rwnoset;
+ else
+ *flags |= options[i].rwset;
+ break;
+
+ /* If we're beyond 's' alphabetically, we're done */
+ } else if (res < 0)
+ break;
+ }
+ if (! found)
+ if (add_extra_option(extra, opt) != 0)
+ return -1;
+ }
+
+ return 0;
+}
+
/* Create the device node "name" */
int create_dev(const char *name, dev_t dev)
{
@@ -241,17 +383,15 @@ static char *prepend_root_dir(const char *src)
int do_cmdline_mounts(int argc, char *argv[])
{
int arg_i;
+ int ret = 0;
for (arg_i = 0; arg_i < argc; arg_i++) {
const char *fs_dev, *fs_dir, *fs_type;
char *fs_opts;
unsigned long flags = 0;
- char new_fs_opts[128] = { 0 };
char *saveptr = NULL;
- char *fs_opts_savedptr = NULL;
- int opt_first = 1;
- const char *opt;
char *new_dir;
+ struct extra_opts extra = { 0, 0, 0, 0 };
if (strncmp(argv[arg_i], "kinit_mount=", 12))
continue;
@@ -275,59 +415,55 @@ int do_cmdline_mounts(int argc, char *argv[])
continue;
}
fs_opts = strtok_r(NULL, ";", &saveptr);
- if (!fs_opts) {
- fprintf(stderr, "Failed to parse fs_opts\n");
- continue;
- }
+ /* Don't error if there is no option string sent */
- /* If 'fs_opts' specifies 'ro' or 'bind', gobble it up. */
- while ((opt = strtok_r((opt_first ? fs_opts : NULL),
- ",", &fs_opts_savedptr))) {
- if (!strcmp(opt, "ro"))
- flags |= MS_RDONLY;
- else if (!strcmp(opt, "bind"))
- flags |= MS_BIND;
- else {
- if (!opt_first)
- strcat(new_fs_opts, ",");
- strcat(new_fs_opts, opt);
- }
- if (opt_first)
- opt_first = 0;
- }
new_dir = prepend_root_dir(fs_dir);
if (! new_dir)
return -ENOMEM;
create_dev_if_not_present(fs_dev);
+ ret = parse_mount_options(fs_opts, &flags, &extra);
+ if (ret != 0)
+ break;
if (!mount_block(fs_dev, new_dir, fs_type,
- flags, new_fs_opts))
+ flags, extra.str))
fprintf(stderr, "Skipping failed mount '%s'\n", fs_dev);
-
free(new_dir);
+ if (extra.str)
+ free(extra.str);
}
- return 0;
+ return ret;
}
int do_fstab_mounts(FILE *fp)
{
struct mntent *ent = NULL;
char *new_dir;
+ int ret = 0;
while ((ent = getmntent(fp))) {
+ unsigned long flags = 0;
+ struct extra_opts extra = { 0, 0, 0, 0 };
+
new_dir = prepend_root_dir(ent->mnt_dir);
if (! new_dir)
return -ENOMEM;
create_dev_if_not_present(ent->mnt_fsname);
+ ret = parse_mount_options(ent->mnt_opts, &flags, &extra);
+ if (ret != 0)
+ break;
+
if (!mount_block(ent->mnt_fsname,
new_dir,
ent->mnt_type,
- 0,
- ent->mnt_opts)) {
+ flags,
+ extra.str)) {
fprintf(stderr, "Skipping failed mount '%s'\n",
ent->mnt_fsname);
}
free(new_dir);
+ if (extra.str)
+ free(extra.str);
}
return 0;
}
--
1.7.7.3
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