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-rw-r--r--src/shared/fstab-util.c288
1 files changed, 288 insertions, 0 deletions
diff --git a/src/shared/fstab-util.c b/src/shared/fstab-util.c
new file mode 100644
index 0000000..f683f05
--- /dev/null
+++ b/src/shared/fstab-util.c
@@ -0,0 +1,288 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "alloc-util.h"
+#include "device-nodes.h"
+#include "fstab-util.h"
+#include "macro.h"
+#include "mount-util.h"
+#include "nulstr-util.h"
+#include "parse-util.h"
+#include "path-util.h"
+#include "string-util.h"
+#include "strv.h"
+
+int fstab_has_fstype(const char *fstype) {
+ _cleanup_endmntent_ FILE *f = NULL;
+ struct mntent *m;
+
+ f = setmntent(fstab_path(), "re");
+ if (!f)
+ return errno == ENOENT ? false : -errno;
+
+ for (;;) {
+ errno = 0;
+ m = getmntent(f);
+ if (!m)
+ return errno != 0 ? -errno : false;
+
+ if (streq(m->mnt_type, fstype))
+ return true;
+ }
+ return false;
+}
+
+bool fstab_is_extrinsic(const char *mount, const char *opts) {
+
+ /* Don't bother with the OS data itself */
+ if (PATH_IN_SET(mount,
+ "/",
+ "/usr",
+ "/etc"))
+ return true;
+
+ if (PATH_STARTSWITH_SET(mount,
+ "/run/initramfs", /* This should stay around from before we boot until after we shutdown */
+ "/proc", /* All of this is API VFS */
+ "/sys", /* … dito … */
+ "/dev")) /* … dito … */
+ return true;
+
+ /* If this is an initrd mount, and we are not in the initrd, then leave
+ * this around forever, too. */
+ if (opts && fstab_test_option(opts, "x-initrd.mount\0") && !in_initrd())
+ return true;
+
+ return false;
+}
+
+int fstab_is_mount_point(const char *mount) {
+ _cleanup_endmntent_ FILE *f = NULL;
+ struct mntent *m;
+
+ f = setmntent(fstab_path(), "re");
+ if (!f)
+ return errno == ENOENT ? false : -errno;
+
+ for (;;) {
+ errno = 0;
+ m = getmntent(f);
+ if (!m)
+ return errno != 0 ? -errno : false;
+
+ if (path_equal(m->mnt_dir, mount))
+ return true;
+ }
+ return false;
+}
+
+int fstab_filter_options(
+ const char *opts,
+ const char *names,
+ const char **ret_namefound,
+ char **ret_value,
+ char ***ret_values,
+ char **ret_filtered) {
+
+ const char *name, *namefound = NULL, *x;
+ _cleanup_strv_free_ char **stor = NULL, **values = NULL;
+ _cleanup_free_ char *value = NULL, **filtered = NULL;
+ int r;
+
+ assert(names && *names);
+ assert(!(ret_value && ret_values));
+
+ if (!opts)
+ goto answer;
+
+ /* Finds any options matching 'names', and returns:
+ * - the last matching option name in ret_namefound,
+ * - the last matching value in ret_value,
+ * - any matching values in ret_values,
+ * - the rest of the option string in ret_filtered.
+ *
+ * If !ret_value and !ret_values and !ret_filtered, this function is not allowed to fail.
+ *
+ * Returns negative on error, true if any matching options were found, false otherwise. */
+
+ if (ret_filtered || ret_value || ret_values) {
+ /* For backwards compatibility, we need to pass-through escape characters.
+ * The only ones we "consume" are the ones used as "\," or "\\". */
+ r = strv_split_full(&stor, opts, ",", EXTRACT_UNESCAPE_SEPARATORS | EXTRACT_UNESCAPE_RELAX);
+ if (r < 0)
+ return r;
+
+ filtered = memdup(stor, sizeof(char*) * (strv_length(stor) + 1));
+ if (!filtered)
+ return -ENOMEM;
+
+ char **t = filtered;
+ for (char **s = t; *s; s++) {
+ NULSTR_FOREACH(name, names) {
+ x = startswith(*s, name);
+ if (!x)
+ continue;
+ /* Match name, but when ret_values, only when followed by assignment. */
+ if (*x == '=' || (!ret_values && *x == '\0'))
+ goto found;
+ }
+
+ *t = *s;
+ t++;
+ continue;
+ found:
+ /* Keep the last occurrence found */
+ namefound = name;
+
+ if (ret_value || ret_values) {
+ assert(IN_SET(*x, '=', '\0'));
+
+ if (ret_value) {
+ r = free_and_strdup(&value, *x == '=' ? x + 1 : NULL);
+ if (r < 0)
+ return r;
+ } else if (*x) {
+ r = strv_extend(&values, x + 1);
+ if (r < 0)
+ return r;
+ }
+ }
+ }
+ *t = NULL;
+ } else
+ for (const char *word = opts;;) {
+ const char *end = word;
+
+ /* Look for a *non-escaped* comma separator. Only commas and backslashes can be
+ * escaped, so "\," and "\\" are the only valid escape sequences, and we can do a
+ * very simple test here. */
+ for (;;) {
+ end += strcspn(end, ",\\");
+
+ if (IN_SET(*end, ',', '\0'))
+ break;
+ assert(*end == '\\');
+ end ++; /* Skip the backslash */
+ if (*end != '\0')
+ end ++; /* Skip the escaped char, but watch out for a trailing comma */
+ }
+
+ NULSTR_FOREACH(name, names) {
+ if (end < word + strlen(name))
+ continue;
+ if (!strneq(word, name, strlen(name)))
+ continue;
+
+ /* We know that the string is NUL terminated, so *x is valid */
+ x = word + strlen(name);
+ if (IN_SET(*x, '\0', '=', ',')) {
+ namefound = name;
+ break;
+ }
+ }
+
+ if (*end)
+ word = end + 1;
+ else
+ break;
+ }
+
+answer:
+ if (ret_namefound)
+ *ret_namefound = namefound;
+ if (ret_filtered) {
+ char *f;
+
+ f = strv_join_full(filtered, ",", NULL, true);
+ if (!f)
+ return -ENOMEM;
+
+ *ret_filtered = f;
+ }
+ if (ret_value)
+ *ret_value = TAKE_PTR(value);
+ if (ret_values)
+ *ret_values = TAKE_PTR(values);
+
+ return !!namefound;
+}
+
+int fstab_find_pri(const char *options, int *ret) {
+ _cleanup_free_ char *opt = NULL;
+ int r, pri;
+
+ assert(ret);
+
+ r = fstab_filter_options(options, "pri\0", NULL, &opt, NULL, NULL);
+ if (r < 0)
+ return r;
+ if (r == 0 || !opt)
+ return 0;
+
+ r = safe_atoi(opt, &pri);
+ if (r < 0)
+ return r;
+
+ *ret = pri;
+ return 1;
+}
+
+static char *unquote(const char *s, const char* quotes) {
+ size_t l;
+ assert(s);
+
+ /* This is rather stupid, simply removes the heading and
+ * trailing quotes if there is one. Doesn't care about
+ * escaping or anything.
+ *
+ * DON'T USE THIS FOR NEW CODE ANYMORE! */
+
+ l = strlen(s);
+ if (l < 2)
+ return strdup(s);
+
+ if (strchr(quotes, s[0]) && s[l-1] == s[0])
+ return strndup(s+1, l-2);
+
+ return strdup(s);
+}
+
+static char *tag_to_udev_node(const char *tagvalue, const char *by) {
+ _cleanup_free_ char *t = NULL, *u = NULL;
+ size_t enc_len;
+
+ u = unquote(tagvalue, QUOTES);
+ if (!u)
+ return NULL;
+
+ enc_len = strlen(u) * 4 + 1;
+ t = new(char, enc_len);
+ if (!t)
+ return NULL;
+
+ if (encode_devnode_name(u, t, enc_len) < 0)
+ return NULL;
+
+ return strjoin("/dev/disk/by-", by, "/", t);
+}
+
+char *fstab_node_to_udev_node(const char *p) {
+ assert(p);
+
+ if (startswith(p, "LABEL="))
+ return tag_to_udev_node(p+6, "label");
+
+ if (startswith(p, "UUID="))
+ return tag_to_udev_node(p+5, "uuid");
+
+ if (startswith(p, "PARTUUID="))
+ return tag_to_udev_node(p+9, "partuuid");
+
+ if (startswith(p, "PARTLABEL="))
+ return tag_to_udev_node(p+10, "partlabel");
+
+ return strdup(p);
+}
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