/**
* mnt_update_force_rdonly:
* @upd: update
* @rdonly: is read-only?
*
* Returns: 0 on success and negative number in case of error.
*/
int mnt_update_force_rdonly(struct libmnt_update *upd, int rdonly)
{
int rc = 0;
if (!upd || !upd->fs)
return -EINVAL;
if (rdonly && (upd->mountflags & MS_RDONLY))
return 0;
if (!rdonly && !(upd->mountflags & MS_RDONLY))
return 0;
if (!upd->userspace_only) {
/* /etc/mtab -- we care about VFS options there */
const char *o = mnt_fs_get_options(upd->fs);
char *n = o ? strdup(o) : NULL;
if (n)
mnt_optstr_remove_option(&n, rdonly ? "rw" : "ro");
if (!mnt_optstr_prepend_option(&n, rdonly ? "ro" : "rw", NULL))
rc = mnt_fs_set_options(upd->fs, n);
free(n);
}
if (rdonly)
upd->mountflags &= ~MS_RDONLY;
else
upd->mountflags |= MS_RDONLY;
return rc;
}
/**
* mnt_optstr_apply_flags:
* @optstr: string with comma separated list of options
* @flags: returns mount flags
* @map: options map
*
* Removes/adds options to the @optstr according to flags. For example:
*
* MS_NOATIME and "foo,bar,noexec" --returns-> "foo,bar,noatime"
*
* Returns: 0 on success or negative number in case of error.
*/
int mnt_optstr_apply_flags(char **optstr, unsigned long flags,
const struct libmnt_optmap *map)
{
struct libmnt_optmap const *maps[1];
char *name, *next, *val;
size_t namesz = 0, valsz = 0;
unsigned long fl;
int rc = 0;
assert(optstr);
if (!optstr || !map)
return -EINVAL;
DBG(CXT, mnt_debug("applying 0x%08lu flags to '%s'", flags, *optstr));
maps[0] = map;
next = *optstr;
fl = flags;
/*
* There is a convention that 'rw/ro' flags are always at the beginning of
* the string (although the 'rw' is unnecessary).
*/
if (map == mnt_get_builtin_optmap(MNT_LINUX_MAP)) {
const char *o = (fl & MS_RDONLY) ? "ro" : "rw";
if (next &&
(!strncmp(next, "rw", 2) || !strncmp(next, "ro", 2)) &&
(*(next + 2) == '\0' || *(next + 2) == ',')) {
/* already set, be paranoid and fix it */
memcpy(next, o, 2);
} else {
rc = mnt_optstr_prepend_option(optstr, o, NULL);
if (rc)
goto err;
next = *optstr; /* because realloc() */
}
fl &= ~MS_RDONLY;
next += 2;
if (*next == ',')
next++;
}
if (next && *next) {
/*
* scan @optstr and remove options that are missing in
* @flags
*/
while(!mnt_optstr_next_option(&next, &name, &namesz,
&val, &valsz)) {
const struct libmnt_optmap *ent;
if (mnt_optmap_get_entry(maps, 1, name, namesz, &ent)) {
/*
* remove unwanted option (rw/ro is already set)
*/
if (!ent || !ent->id)
continue;
/* ignore name=<value> if options map expects <name> only */
if (valsz && mnt_optmap_entry_novalue(ent))
continue;
if (ent->id == MS_RDONLY ||
(ent->mask & MNT_INVERT) ||
(fl & ent->id) != (unsigned long) ent->id) {
char *end = val ? val + valsz :
name + namesz;
next = name;
rc = mnt_optstr_remove_option_at(
optstr, name, end);
if (rc)
goto err;
}
if (!(ent->mask & MNT_INVERT))
fl &= ~ent->id;
}
}
}
/* add missing options */
if (fl) {
const struct libmnt_optmap *ent;
char *p;
for (ent = map; ent && ent->name; ent++) {
if ((ent->mask & MNT_INVERT)
|| ent->id == 0
|| (fl & ent->id) != (unsigned long) ent->id)
continue;
/* don't add options which require values (e.g. offset=%d) */
p = strchr(ent->name, '=');
if (p) {
if (p > ent->name && *(p - 1) == '[')
p--; /* name[=] */
else
continue; /* name= */
p = strndup(ent->name, p - ent->name);
if (!p) {
rc = -ENOMEM;
goto err;
}
mnt_optstr_append_option(optstr, p, NULL);
free(p);
} else
mnt_optstr_append_option(optstr, ent->name, NULL);
}
}
DBG(CXT, mnt_debug("new optstr '%s'", *optstr));
return rc;
err:
DBG(CXT, mnt_debug("failed to apply flags [rc=%d]", rc));
return rc;
}