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machined: make image locking runtime scope aware, too

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We cannot create an image lock in /run if we are unpriv, hence create it
in $XDG_RUNTIME_DIR instead.
This commit is contained in:
Lennart Poettering
2025-09-25 22:43:59 +02:00
parent 1966baf2d6
commit d9c5566c0f
8 changed files with 97 additions and 47 deletions
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src/shared/discover-image.c
+65 -24
View File
@@ -19,6 +19,7 @@
#include "chase.h"
#include "chattr-util.h"
#include "copy.h"
#include "devnum-util.h"
#include "dirent-util.h"
#include "discover-image.h"
#include "dissect-image.h"
@@ -37,6 +38,7 @@
#include "mkdir.h"
#include "nulstr-util.h"
#include "os-util.h"
#include "path-lookup.h"
#include "path-util.h"
#include "rm-rf.h"
#include "runtime-scope.h"
@@ -1149,7 +1151,7 @@ int image_remove(Image *i, RuntimeScope scope) {
return r;
/* Make sure we don't interfere with a running nspawn */
r = image_path_lock(i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
r = image_path_lock(scope, i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
@@ -1244,14 +1246,14 @@ int image_rename(Image *i, const char *new_name, RuntimeScope scope) {
return r;
/* Make sure we don't interfere with a running nspawn */
r = image_path_lock(i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
r = image_path_lock(scope, i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
/* Make sure nobody takes the new name, between the time we
* checked it is currently unused in all search paths, and the
* time we take possession of it */
r = image_name_lock(new_name, LOCK_EX|LOCK_NB, &name_lock);
r = image_name_lock(scope, new_name, LOCK_EX|LOCK_NB, &name_lock);
if (r < 0)
return r;
@@ -1418,7 +1420,7 @@ int image_clone(Image *i, const char *new_name, bool read_only, RuntimeScope sco
/* Make sure nobody takes the new name, between the time we
* checked it is currently unused in all search paths, and the
* time we take possession of it */
r = image_name_lock(new_name, LOCK_EX|LOCK_NB, &name_lock);
r = image_name_lock(scope, new_name, LOCK_EX|LOCK_NB, &name_lock);
if (r < 0)
return r;
@@ -1485,7 +1487,7 @@ int image_clone(Image *i, const char *new_name, bool read_only, RuntimeScope sco
return 0;
}
int image_read_only(Image *i, bool b) {
int image_read_only(Image *i, bool b, RuntimeScope scope) {
_cleanup_(release_lock_file) LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
int r;
@@ -1495,7 +1497,7 @@ int image_read_only(Image *i, bool b) {
return -EROFS;
/* Make sure we don't interfere with a running nspawn */
r = image_path_lock(i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
r = image_path_lock(scope, i->path, LOCK_EX|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
@@ -1572,12 +1574,33 @@ int image_read_only(Image *i, bool b) {
return 0;
}
static void make_lock_dir(void) {
(void) mkdir_p("/run/systemd/nspawn", 0755);
(void) mkdir("/run/systemd/nspawn/locks", 0700);
static int make_lock_dir(RuntimeScope scope) {
int r;
_cleanup_free_ char *p = NULL;
r = runtime_directory_generic(scope, "systemd", &p);
if (r < 0)
return r;
_cleanup_close_ int pfd = open_mkdir_at(AT_FDCWD, p, O_CLOEXEC, 0755);
if (pfd < 0)
return pfd;
_cleanup_close_ int nfd = open_mkdir_at(pfd, "nspawn", O_CLOEXEC, 0755);
if (nfd < 0)
return nfd;
r = RET_NERRNO(mkdirat(nfd, "locks", 0700));
if (r == -EEXIST)
return 0;
if (r < 0)
return r;
return 1;
}
int image_path_lock(
RuntimeScope scope,
const char *path,
int operation,
LockFile *ret_global,
@@ -1593,7 +1616,7 @@ int image_path_lock(
assert(ret_local);
/* Locks an image path. This actually creates two locks: one "local" one, next to the image path
* itself, which might be shared via NFS. And another "global" one, in /run, that uses the
* itself, which might be shared via NFS. And another "global" one, in /run/, that uses the
* device/inode number. This has the benefit that we can even lock a tree that is a mount point,
* correctly. */
@@ -1637,15 +1660,21 @@ int image_path_lock(
}
if (ret_global) {
if (stat(path, &st) >= 0) {
if (stat(path, &st) < 0)
log_debug_errno(errno, "Failed to stat() image '%s', not locking image: %m", path);
else {
r = runtime_directory_generic(scope, "systemd/nspawn/locks/", &p);
if (r < 0)
return r;
if (S_ISBLK(st.st_mode))
r = asprintf(&p, "/run/systemd/nspawn/locks/block-%u:%u", major(st.st_rdev), minor(st.st_rdev));
r = strextendf(&p, "block-" DEVNUM_FORMAT_STR, DEVNUM_FORMAT_VAL(st.st_rdev));
else if (S_ISDIR(st.st_mode) || S_ISREG(st.st_mode))
r = asprintf(&p, "/run/systemd/nspawn/locks/inode-%lu:%lu", (unsigned long) st.st_dev, (unsigned long) st.st_ino);
r = strextendf(&p, "inode-%" PRIu64 ":%" PRIu64, (uint64_t) st.st_dev, (uint64_t) st.st_ino);
else
return -ENOTTY;
if (r < 0)
return -ENOMEM;
return r;
}
}
@@ -1654,15 +1683,15 @@ int image_path_lock(
if (!path_startswith(path, "/dev/")) {
r = make_lock_file_for(path, operation, &t);
if (r < 0) {
if (!exclusive && r == -EROFS)
log_debug_errno(r, "Failed to create shared lock for '%s', ignoring: %m", path);
else
if (exclusive || r != -EROFS)
return r;
log_debug_errno(r, "Failed to create shared lock for '%s', ignoring: %m", path);
}
}
if (p) {
make_lock_dir();
(void) make_lock_dir(scope);
r = make_lock_file(p, operation, ret_global);
if (r < 0) {
@@ -1728,13 +1757,13 @@ int image_set_pool_limit(RuntimeScope scope, ImageClass class, uint64_t referenc
return 0;
}
int image_read_metadata(Image *i, const ImagePolicy *image_policy) {
int image_read_metadata(Image *i, const ImagePolicy *image_policy, RuntimeScope scope) {
_cleanup_(release_lock_file) LockFile global_lock = LOCK_FILE_INIT, local_lock = LOCK_FILE_INIT;
int r;
assert(i);
r = image_path_lock(i->path, LOCK_SH|LOCK_NB, &global_lock, &local_lock);
r = image_path_lock(scope, i->path, LOCK_SH|LOCK_NB, &global_lock, &local_lock);
if (r < 0)
return r;
@@ -1864,8 +1893,13 @@ int image_read_metadata(Image *i, const ImagePolicy *image_policy) {
return 0;
}
int image_name_lock(const char *name, int operation, LockFile *ret) {
const char *p;
int image_name_lock(
RuntimeScope scope,
const char *name,
int operation,
LockFile *ret) {
int r;
assert(name);
assert(ret);
@@ -1883,9 +1917,16 @@ int image_name_lock(const char *name, int operation, LockFile *ret) {
return 0;
}
make_lock_dir();
(void) make_lock_dir(scope);
_cleanup_free_ char *p = NULL;
r = runtime_directory_generic(scope, "systemd/nspawn/locks/name-", &p);
if (r < 0)
return r;
if (!strextend(&p, name))
return -ENOMEM;
p = strjoina("/run/systemd/nspawn/locks/name-", name);
return make_lock_file(p, operation, ret);
}
src/shared/discover-image.h
+4 -4
View File
@@ -58,18 +58,18 @@ int image_discover(RuntimeScope scope, ImageClass class, const char *root, Hashm
int image_remove(Image *i, RuntimeScope scope);
int image_rename(Image *i, const char *new_name, RuntimeScope scope);
int image_clone(Image *i, const char *new_name, bool read_only, RuntimeScope scope);
int image_read_only(Image *i, bool b);
int image_read_only(Image *i, bool b, RuntimeScope scope);
const char* image_type_to_string(ImageType t) _const_;
ImageType image_type_from_string(const char *s) _pure_;
int image_path_lock(const char *path, int operation, LockFile *global, LockFile *local);
int image_name_lock(const char *name, int operation, LockFile *ret);
int image_path_lock(RuntimeScope scope, const char *path, int operation, LockFile *global, LockFile *local);
int image_name_lock(RuntimeScope scope, const char *name, int operation, LockFile *ret);
int image_set_limit(Image *i, uint64_t referenced_max);
int image_set_pool_limit(RuntimeScope scope, ImageClass class, uint64_t referenced_max);
int image_read_metadata(Image *i, const ImagePolicy *image_policy);
int image_read_metadata(Image *i, const ImagePolicy *image_policy, RuntimeScope scope);
bool image_in_search_path(RuntimeScope scope, ImageClass class, const char *root, const char *image);