From ca634baa10e2249d4a706d59b67be764867e5f32 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Mon, 30 Nov 2020 10:37:06 +0100
Subject: [PATCH] shared/mount-util: convert to libmount
It seems better to use just a single parsing algorithm for /proc/self/mountinfo.
Also, unify the naming of variables in all places that use mnt_table_next_fs().
It makes it easier to compare the different call sites.
(cherry picked from commit 13dcfe4661b467131c943620d0f44711798bfd54)
Related: #1885143
---
src/basic/mount-util.c | 133 ++++++++++++++++++-----------------------
src/core/mount.c | 22 +++----
src/core/umount.c | 14 ++---
3 files changed, 76 insertions(+), 93 deletions(-)
diff --git a/src/basic/mount-util.c b/src/basic/mount-util.c
index 5b04e21f34..bac1a25cc8 100644
--- a/src/basic/mount-util.c
+++ b/src/basic/mount-util.c
@@ -13,7 +13,6 @@
#include <libmount.h>
#include "alloc-util.h"
-#include "escape.h"
#include "extract-word.h"
#include "fd-util.h"
#include "fileio.h"
@@ -27,6 +26,9 @@
#include "string-util.h"
#include "strv.h"
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct libmnt_table*, mnt_free_table);
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct libmnt_iter*, mnt_free_iter);
+
/* This is the original MAX_HANDLE_SZ definition from the kernel, when the API was introduced. We use that in place of
* any more currently defined value to future-proof things: if the size is increased in the API headers, and our code
* is recompiled then it would cease working on old kernels, as those refuse any sizes larger than this value with
@@ -313,55 +315,43 @@ int umount_recursive(const char *prefix, int flags) {
* unmounting them until they are gone. */
do {
- _cleanup_fclose_ FILE *proc_self_mountinfo = NULL;
+ _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
+ _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
again = false;
- r = 0;
- proc_self_mountinfo = fopen("/proc/self/mountinfo", "re");
- if (!proc_self_mountinfo)
- return -errno;
+ table = mnt_new_table();
+ iter = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!table || !iter)
+ return -ENOMEM;
- (void) __fsetlocking(proc_self_mountinfo, FSETLOCKING_BYCALLER);
+ r = mnt_table_parse_mtab(table, NULL);
+ if (r < 0)
+ return log_debug_errno(r, "Failed to parse /proc/self/mountinfo: %m");
for (;;) {
- _cleanup_free_ char *path = NULL, *p = NULL;
- int k;
-
- k = fscanf(proc_self_mountinfo,
- "%*s " /* (1) mount id */
- "%*s " /* (2) parent id */
- "%*s " /* (3) major:minor */
- "%*s " /* (4) root */
- "%ms " /* (5) mount point */
- "%*s" /* (6) mount options */
- "%*[^-]" /* (7) optional fields */
- "- " /* (8) separator */
- "%*s " /* (9) file system type */
- "%*s" /* (10) mount source */
- "%*s" /* (11) mount options 2 */
- "%*[^\n]", /* some rubbish at the end */
- &path);
- if (k != 1) {
- if (k == EOF)
- break;
+ struct libmnt_fs *fs;
+ const char *path;
- continue;
- }
-
- r = cunescape(path, UNESCAPE_RELAX, &p);
+ r = mnt_table_next_fs(table, iter, &fs);
+ if (r == 1)
+ break;
if (r < 0)
- return r;
+ return log_debug_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
- if (!path_startswith(p, prefix))
+ path = mnt_fs_get_target(fs);
+ if (!path)
continue;
- if (umount2(p, flags) < 0) {
- r = log_debug_errno(errno, "Failed to umount %s: %m", p);
+ if (!path_startswith(path, prefix))
+ continue;
+
+ if (umount2(path, flags) < 0) {
+ r = log_debug_errno(errno, "Failed to umount %s: %m", path);
continue;
}
- log_debug("Successfully unmounted %s", p);
+ log_debug("Successfully unmounted %s", path);
again = true;
n++;
@@ -416,6 +406,8 @@ int bind_remount_recursive_with_mountinfo(const char *prefix, bool ro, char **bl
for (;;) {
_cleanup_set_free_free_ Set *todo = NULL;
+ _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
+ _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
bool top_autofs = false;
char *x;
unsigned long orig_flags;
@@ -424,58 +416,52 @@ int bind_remount_recursive_with_mountinfo(const char *prefix, bool ro, char **bl
if (!todo)
return -ENOMEM;
+ table = mnt_new_table();
+ iter = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!table || !iter)
+ return -ENOMEM;
+
rewind(proc_self_mountinfo);
- for (;;) {
- _cleanup_free_ char *path = NULL, *p = NULL, *type = NULL;
- int k;
-
- k = fscanf(proc_self_mountinfo,
- "%*s " /* (1) mount id */
- "%*s " /* (2) parent id */
- "%*s " /* (3) major:minor */
- "%*s " /* (4) root */
- "%ms " /* (5) mount point */
- "%*s" /* (6) mount options (superblock) */
- "%*[^-]" /* (7) optional fields */
- "- " /* (8) separator */
- "%ms " /* (9) file system type */
- "%*s" /* (10) mount source */
- "%*s" /* (11) mount options (bind mount) */
- "%*[^\n]", /* some rubbish at the end */
- &path,
- &type);
- if (k != 2) {
- if (k == EOF)
- break;
+ r = mnt_table_parse_stream(table, proc_self_mountinfo, "/proc/self/mountinfo");
+ if (r < 0)
+ return log_debug_errno(r, "Failed to parse /proc/self/mountinfo: %m");
- continue;
- }
+ for (;;) {
+ struct libmnt_fs *fs;
+ const char *path, *type;
- r = cunescape(path, UNESCAPE_RELAX, &p);
+ r = mnt_table_next_fs(table, iter, &fs);
+ if (r == 1)
+ break;
if (r < 0)
- return r;
+ return log_debug_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
+
+ path = mnt_fs_get_target(fs);
+ type = mnt_fs_get_fstype(fs);
+ if (!path || !type)
+ continue;
- if (!path_startswith(p, cleaned))
+ if (!path_startswith(path, cleaned))
continue;
- /* Ignore this mount if it is blacklisted, but only if it isn't the top-level mount we shall
- * operate on. */
- if (!path_equal(cleaned, p)) {
+ /* Ignore this mount if it is blacklisted, but only if it isn't the top-level mount
+ * we shall operate on. */
+ if (!path_equal(path, cleaned)) {
bool blacklisted = false;
char **i;
STRV_FOREACH(i, blacklist) {
-
if (path_equal(*i, cleaned))
continue;
if (!path_startswith(*i, cleaned))
continue;
- if (path_startswith(p, *i)) {
+ if (path_startswith(path, *i)) {
blacklisted = true;
- log_debug("Not remounting %s, because blacklisted by %s, called for %s", p, *i, cleaned);
+ log_debug("Not remounting %s blacklisted by %s, called for %s",
+ path, *i, cleaned);
break;
}
}
@@ -490,15 +476,12 @@ int bind_remount_recursive_with_mountinfo(const char *prefix, bool ro, char **bl
* already triggered, then we will find
* another entry for this. */
if (streq(type, "autofs")) {
- top_autofs = top_autofs || path_equal(cleaned, p);
+ top_autofs = top_autofs || path_equal(path, cleaned);
continue;
}
- if (!set_contains(done, p)) {
- r = set_consume(todo, p);
- p = NULL;
- if (r == -EEXIST)
- continue;
+ if (!set_contains(done, path)) {
+ r = set_put_strdup(todo, path);
if (r < 0)
return r;
}
diff --git a/src/core/mount.c b/src/core/mount.c
index 076dfd06a3..7e80a0c974 100644
--- a/src/core/mount.c
+++ b/src/core/mount.c
@@ -1606,18 +1606,18 @@ fail:
}
static int mount_load_proc_self_mountinfo(Manager *m, bool set_flags) {
- _cleanup_(mnt_free_tablep) struct libmnt_table *t = NULL;
- _cleanup_(mnt_free_iterp) struct libmnt_iter *i = NULL;
- int r = 0;
+ _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
+ _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
+ int r;
assert(m);
- t = mnt_new_table();
- i = mnt_new_iter(MNT_ITER_FORWARD);
- if (!t || !i)
+ table = mnt_new_table();
+ iter = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!table || !iter)
return log_oom();
- r = mnt_table_parse_mtab(t, NULL);
+ r = mnt_table_parse_mtab(table, NULL);
if (r < 0)
return log_error_errno(r, "Failed to parse /proc/self/mountinfo: %m");
@@ -1628,11 +1628,11 @@ static int mount_load_proc_self_mountinfo(Manager *m, bool set_flags) {
_cleanup_free_ char *d = NULL, *p = NULL;
int k;
- k = mnt_table_next_fs(t, i, &fs);
- if (k == 1)
+ r = mnt_table_next_fs(table, iter, &fs);
+ if (r == 1)
break;
- if (k < 0)
- return log_error_errno(k, "Failed to get next entry from /proc/self/mountinfo: %m");
+ if (r < 0)
+ return log_error_errno(r, "Failed to get next entry from /proc/self/mountinfo: %m");
device = mnt_fs_get_source(fs);
path = mnt_fs_get_target(fs);
diff --git a/src/core/umount.c b/src/core/umount.c
index 241fe6fc62..3f02bf141a 100644
--- a/src/core/umount.c
+++ b/src/core/umount.c
@@ -55,18 +55,18 @@ void mount_points_list_free(MountPoint **head) {
}
int mount_points_list_get(const char *mountinfo, MountPoint **head) {
- _cleanup_(mnt_free_tablep) struct libmnt_table *t = NULL;
- _cleanup_(mnt_free_iterp) struct libmnt_iter *i = NULL;
+ _cleanup_(mnt_free_tablep) struct libmnt_table *table = NULL;
+ _cleanup_(mnt_free_iterp) struct libmnt_iter *iter = NULL;
int r;
assert(head);
- t = mnt_new_table();
- i = mnt_new_iter(MNT_ITER_FORWARD);
- if (!t || !i)
+ table = mnt_new_table();
+ iter = mnt_new_iter(MNT_ITER_FORWARD);
+ if (!table || !iter)
return log_oom();
- r = mnt_table_parse_mtab(t, mountinfo);
+ r = mnt_table_parse_mtab(table, mountinfo);
if (r < 0)
return log_error_errno(r, "Failed to parse %s: %m", mountinfo);
@@ -79,7 +79,7 @@ int mount_points_list_get(const char *mountinfo, MountPoint **head) {
bool try_remount_ro;
MountPoint *m;
- r = mnt_table_next_fs(t, i, &fs);
+ r = mnt_table_next_fs(table, iter, &fs);
if (r == 1)
break;
if (r < 0)