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Merge pull request #26726 from DaanDeMeyer/cleanups

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Various small cleanups
This commit is contained in:
Daan De Meyer
2023-03-10 14:22:53 +01:00
committed by GitHub
parent d0ed83f3ae 37c485482f
commit aa41079175
13 changed files with 124 additions and 91 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/shared/lockfile-util.c → src/basic/lock-util.c
+54 -36
View File
@@ -10,7 +10,7 @@
#include "alloc-util.h"
#include "fd-util.h"
#include "fs-util.h"
#include "lockfile-util.h"
#include "lock-util.h"
#include "macro.h"
#include "missing_fcntl.h"
#include "path-util.h"
@@ -21,39 +21,25 @@ int make_lock_file(const char *p, int operation, LockFile *ret) {
int r;
assert(p);
assert(IN_SET(operation & ~LOCK_NB, LOCK_EX, LOCK_SH));
assert(ret);
/*
* We use UNPOSIX locks if they are available. They have nice semantics, and are mostly compatible
* with NFS. However, they are only available on new kernels. When we detect we are running on an
* older kernel, then we fall back to good old BSD locks. They also have nice semantics, but are
* slightly problematic on NFS, where they are upgraded to POSIX locks, even though locally they are
* orthogonal to POSIX locks.
*/
/* We use UNPOSIX locks as they have nice semantics, and are mostly compatible with NFS. */
t = strdup(p);
if (!t)
return -ENOMEM;
for (;;) {
struct flock fl = {
.l_type = (operation & ~LOCK_NB) == LOCK_EX ? F_WRLCK : F_RDLCK,
.l_whence = SEEK_SET,
};
struct stat st;
fd = open(p, O_CREAT|O_RDWR|O_NOFOLLOW|O_CLOEXEC|O_NOCTTY, 0600);
if (fd < 0)
return -errno;
r = fcntl(fd, (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW, &fl);
if (r < 0) {
/* If the kernel is too old, use good old BSD locks */
if (errno == EINVAL || ERRNO_IS_NOT_SUPPORTED(errno))
r = flock(fd, operation);
if (r < 0)
return errno == EAGAIN ? -EBUSY : -errno;
}
r = unposix_lock(fd, operation);
if (r < 0)
return r == -EAGAIN ? -EBUSY : r;
/* If we acquired the lock, let's check if the file still exists in the file system. If not,
* then the previous exclusive owner removed it and then closed it. In such a case our
@@ -73,7 +59,7 @@ int make_lock_file(const char *p, int operation, LockFile *ret) {
.operation = operation,
};
return r;
return 0;
}
int make_lock_file_for(const char *p, int operation, LockFile *ret) {
@@ -99,8 +85,6 @@ int make_lock_file_for(const char *p, int operation, LockFile *ret) {
}
void release_lock_file(LockFile *f) {
int r;
if (!f)
return;
@@ -111,19 +95,9 @@ void release_lock_file(LockFile *f) {
* owner, we can try becoming it. */
if (f->fd >= 0 &&
(f->operation & ~LOCK_NB) == LOCK_SH) {
static const struct flock fl = {
.l_type = F_WRLCK,
.l_whence = SEEK_SET,
};
r = fcntl(f->fd, F_OFD_SETLK, &fl);
if (r < 0 && (errno == EINVAL || ERRNO_IS_NOT_SUPPORTED(errno)))
r = flock(f->fd, LOCK_EX|LOCK_NB);
if (r >= 0)
f->operation = LOCK_EX|LOCK_NB;
}
(f->operation & ~LOCK_NB) == LOCK_SH &&
unposix_lock(f->fd, LOCK_EX|LOCK_NB) >= 0)
f->operation = LOCK_EX|LOCK_NB;
if ((f->operation & ~LOCK_NB) == LOCK_EX)
unlink_noerrno(f->path);
@@ -134,3 +108,47 @@ void release_lock_file(LockFile *f) {
f->fd = safe_close(f->fd);
f->operation = 0;
}
int unposix_lock(int fd, int operation) {
int cmd, type, r;
assert(fd >= 0);
cmd = (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW;
switch (operation & ~LOCK_NB) {
case LOCK_EX:
type = F_WRLCK;
break;
case LOCK_SH:
type = F_RDLCK;
break;
case LOCK_UN:
type = F_UNLCK;
break;
default:
assert_not_reached();
}
r = RET_NERRNO(fcntl(fd, cmd, &(struct flock) {
.l_type = type,
.l_whence = SEEK_SET,
.l_start = 0,
.l_len = 0,
}));
if (r == -EACCES) /* Treat EACCESS/EAGAIN the same as per man page. */
r = -EAGAIN;
return r;
}
void unposix_unlockpp(int **fd) {
assert(fd);
if (!*fd || **fd < 0)
return;
(void) unposix_lock(**fd, LOCK_UN);
*fd = NULL;
}
src/shared/lockfile-util.h → src/basic/lock-util.h
+8
View File
@@ -12,3 +12,11 @@ int make_lock_file_for(const char *p, int operation, LockFile *ret);
void release_lock_file(LockFile *f);
#define LOCK_FILE_INIT { .fd = -EBADF, .path = NULL }
/* Open File Description locks with the same interface as flock(). */
int unposix_lock(int fd, int operation);
void unposix_unlockpp(int **fd);
#define CLEANUP_UNPOSIX_UNLOCK(fd) \
_cleanup_(unposix_unlockpp) _unused_ int *CONCATENATE(_cleanup_unposix_unlock_, UNIQ) = &(fd)
src/basic/memfd-util.c
+31
View File
@@ -133,3 +133,34 @@ int memfd_new_and_map(const char *name, size_t sz, void **p) {
return TAKE_FD(fd);
}
int memfd_new_and_seal(const char *name, const void *data, size_t sz) {
_cleanup_close_ int fd = -EBADF;
ssize_t n;
off_t f;
int r;
assert(data || sz == 0);
fd = memfd_new(name);
if (fd < 0)
return fd;
if (sz > 0) {
n = write(fd, data, sz);
if (n < 0)
return -errno;
if ((size_t) n != sz)
return -EIO;
f = lseek(fd, 0, SEEK_SET);
if (f != 0)
return -errno;
}
r = memfd_set_sealed(fd);
if (r < 0)
return r;
return TAKE_FD(fd);
}
src/basic/memfd-util.h
+1
View File
@@ -8,6 +8,7 @@
int memfd_new(const char *name);
int memfd_new_and_map(const char *name, size_t sz, void **p);
int memfd_new_and_seal(const char *name, const void *data, size_t sz);
int memfd_map(int fd, uint64_t offset, size_t size, void **p);
src/basic/meson.build
+1
View File
@@ -46,6 +46,7 @@ basic_sources = files(
'ioprio-util.c',
'limits-util.c',
'locale-util.c',
'lock-util.c',
'log.c',
'login-util.c',
'memfd-util.c',
src/basic/user-util.c
+5 -8
View File
@@ -18,6 +18,7 @@
#include "fd-util.h"
#include "fileio.h"
#include "format-util.h"
#include "lock-util.h"
#include "macro.h"
#include "mkdir.h"
#include "parse-util.h"
@@ -671,12 +672,7 @@ int reset_uid_gid(void) {
}
int take_etc_passwd_lock(const char *root) {
struct flock flock = {
.l_type = F_WRLCK,
.l_whence = SEEK_SET,
.l_start = 0,
.l_len = 0,
};
int r;
/* This is roughly the same as lckpwdf(), but not as awful. We don't want to use alarm() and signals,
* hence we implement our own trivial version of this.
@@ -695,8 +691,9 @@ int take_etc_passwd_lock(const char *root) {
if (fd < 0)
return log_debug_errno(errno, "Cannot open %s: %m", path);
if (fcntl(fd, F_SETLKW, &flock) < 0)
return log_debug_errno(errno, "Locking %s failed: %m", path);
r = unposix_lock(fd, LOCK_EX);
if (r < 0)
return log_debug_errno(r, "Locking %s failed: %m", path);
return TAKE_FD(fd);
}
src/core/dynamic-user.c
+14 -22
View File
@@ -11,6 +11,7 @@
#include "format-util.h"
#include "fs-util.h"
#include "io-util.h"
#include "lock-util.h"
#include "nscd-flush.h"
#include "parse-util.h"
#include "random-util.h"
@@ -362,27 +363,12 @@ static void unlink_uid_lock(int lock_fd, uid_t uid, const char *name) {
(void) make_uid_symlinks(uid, name, false); /* remove direct lookup symlinks */
}
static int lockfp(int fd, int *fd_lock) {
if (lockf(fd, F_LOCK, 0) < 0)
return -errno;
*fd_lock = fd;
return 0;
}
static void unlockfp(int *fd_lock) {
if (*fd_lock < 0)
return;
lockf(*fd_lock, F_ULOCK, 0);
*fd_lock = -EBADF;
}
static int dynamic_user_realize(
DynamicUser *d,
char **suggested_dirs,
uid_t *ret_uid, gid_t *ret_gid,
bool is_user) {
_cleanup_(unlockfp) int storage_socket0_lock = -EBADF;
_cleanup_close_ int uid_lock_fd = -EBADF;
_cleanup_close_ int etc_passwd_lock_fd = -EBADF;
uid_t num = UID_INVALID; /* a uid if is_user, and a gid otherwise */
@@ -397,10 +383,12 @@ static int dynamic_user_realize(
/* Acquire a UID for the user name. This will allocate a UID for the user name if the user doesn't exist
* yet. If it already exists its existing UID/GID will be reused. */
r = lockfp(d->storage_socket[0], &storage_socket0_lock);
r = unposix_lock(d->storage_socket[0], LOCK_EX);
if (r < 0)
return r;
CLEANUP_UNPOSIX_UNLOCK(d->storage_socket[0]);
r = dynamic_user_pop(d, &num, &uid_lock_fd);
if (r < 0) {
int new_uid_lock_fd;
@@ -411,7 +399,9 @@ static int dynamic_user_realize(
/* OK, nothing stored yet, let's try to find something useful. While we are working on this release the
* lock however, so that nobody else blocks on our NSS lookups. */
unlockfp(&storage_socket0_lock);
r = unposix_lock(d->storage_socket[0], LOCK_UN);
if (r < 0)
return r;
/* Let's see if a proper, static user or group by this name exists. Try to take the lock on
* /etc/passwd, if that fails with EROFS then /etc is read-only. In that case it's fine if we don't
@@ -461,7 +451,7 @@ static int dynamic_user_realize(
}
/* So, we found a working UID/lock combination. Let's see if we actually still need it. */
r = lockfp(d->storage_socket[0], &storage_socket0_lock);
r = unposix_lock(d->storage_socket[0], LOCK_EX);
if (r < 0) {
unlink_uid_lock(uid_lock_fd, num, d->name);
return r;
@@ -524,7 +514,6 @@ static int dynamic_user_realize(
}
int dynamic_user_current(DynamicUser *d, uid_t *ret) {
_cleanup_(unlockfp) int storage_socket0_lock = -EBADF;
_cleanup_close_ int lock_fd = -EBADF;
uid_t uid;
int r;
@@ -534,10 +523,12 @@ int dynamic_user_current(DynamicUser *d, uid_t *ret) {
/* Get the currently assigned UID for the user, if there's any. This simply pops the data from the
* storage socket, and pushes it back in right-away. */
r = lockfp(d->storage_socket[0], &storage_socket0_lock);
r = unposix_lock(d->storage_socket[0], LOCK_EX);
if (r < 0)
return r;
CLEANUP_UNPOSIX_UNLOCK(d->storage_socket[0]);
r = dynamic_user_pop(d, &uid, &lock_fd);
if (r < 0)
return r;
@@ -567,7 +558,6 @@ static DynamicUser* dynamic_user_unref(DynamicUser *d) {
}
static int dynamic_user_close(DynamicUser *d) {
_cleanup_(unlockfp) int storage_socket0_lock = -EBADF;
_cleanup_close_ int lock_fd = -EBADF;
uid_t uid;
int r;
@@ -575,10 +565,12 @@ static int dynamic_user_close(DynamicUser *d) {
/* Release the user ID, by releasing the lock on it, and emptying the storage socket. After this the
* user is unrealized again, much like it was after it the DynamicUser object was first allocated. */
r = lockfp(d->storage_socket[0], &storage_socket0_lock);
r = unposix_lock(d->storage_socket[0], LOCK_EX);
if (r < 0)
return r;
CLEANUP_UNPOSIX_UNLOCK(d->storage_socket[0]);
r = dynamic_user_pop(d, &uid, &lock_fd);
if (r == -EAGAIN)
/* User wasn't realized yet, nothing to do. */
src/journal/fuzz-journald-native-fd.c
+1 -4
View File
@@ -23,11 +23,8 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
dummy_server_init(&s, NULL, 0);
sealed_fd = memfd_new(NULL);
sealed_fd = memfd_new_and_seal(NULL, data, size);
assert_se(sealed_fd >= 0);
assert_se(write(sealed_fd, data, size) == (ssize_t) size);
assert_se(memfd_set_sealed(sealed_fd) >= 0);
assert_se(lseek(sealed_fd, 0, SEEK_SET) == 0);
ucred = (struct ucred) {
.pid = getpid_cached(),
.uid = geteuid(),
src/nspawn/nspawn-network.c
+1 -1
View File
@@ -12,7 +12,7 @@
#include "alloc-util.h"
#include "ether-addr-util.h"
#include "hexdecoct.h"
#include "lockfile-util.h"
#include "lock-util.h"
#include "missing_network.h"
#include "netif-naming-scheme.h"
#include "netlink-util.h"
src/shared/data-fd-util.c
+6 -17
View File
@@ -30,7 +30,6 @@ int acquire_data_fd(const void *data, size_t size, unsigned flags) {
_cleanup_close_ int fd = -EBADF;
int isz = 0, r;
ssize_t n;
off_t f;
assert(data || size == 0);
@@ -58,23 +57,13 @@ int acquire_data_fd(const void *data, size_t size, unsigned flags) {
return RET_NERRNO(open("/dev/null", O_RDONLY|O_CLOEXEC|O_NOCTTY));
if ((flags & ACQUIRE_NO_MEMFD) == 0) {
fd = memfd_new("data-fd");
if (fd < 0)
goto try_pipe;
fd = memfd_new_and_seal("data-fd", data, size);
if (fd < 0) {
if (ERRNO_IS_NOT_SUPPORTED(fd))
goto try_pipe;
n = write(fd, data, size);
if (n < 0)
return -errno;
if ((size_t) n != size)
return -EIO;
f = lseek(fd, 0, SEEK_SET);
if (f != 0)
return -errno;
r = memfd_set_sealed(fd);
if (r < 0)
return r;
return fd;
}
return TAKE_FD(fd);
}
src/shared/discover-image.c
+1 -1
View File
@@ -27,7 +27,7 @@
#include "hashmap.h"
#include "hostname-setup.h"
#include "id128-util.h"
#include "lockfile-util.h"
#include "lock-util.h"
#include "log.h"
#include "loop-util.h"
#include "macro.h"
src/shared/discover-image.h
+1 -1
View File
@@ -7,7 +7,7 @@
#include "sd-id128.h"
#include "hashmap.h"
#include "lockfile-util.h"
#include "lock-util.h"
#include "macro.h"
#include "path-util.h"
#include "string-util.h"
src/shared/meson.build
-1
View File
@@ -98,7 +98,6 @@ shared_sources = files(
'libmount-util.c',
'local-addresses.c',
'locale-setup.c',
'lockfile-util.c',
'logs-show.c',
'loop-util.c',
'loopback-setup.c',