14895667988

Committed 07 May 2025 08:57PM UTC coverage: 72.225% (-0.007%) from 72.232%

Build # 14895667988

Build Type

push

github

Committed by

yuwata

Commit Message

network: log_link_message_debug_errno() automatically append %m if necessary

Follow-up for d28746ef5.
Fixes CID#1609753.

Coverage Stats

0 of 1 new or added line in 1 file covered. (0.0%)

20297 existing lines in 338 files now uncovered.

297407 of 411780 relevant lines covered (72.22%)

695716.85 hits per line

Source File
Press 'n' to go to next uncovered line, 'b' for previous

84.38

/src/basic/lock-util.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <sys/wait.h>

#include "alloc-util.h"
#include "errno-util.h"
#include "fd-util.h"
#include "fs-util.h"
#include "lock-util.h"
#include "log.h"
#include "macro.h"
#include "missing_fcntl.h"
#include "path-util.h"
#include "process-util.h"

int make_lock_file_at(int dir_fd, const char *p, int operation, LockFile *ret) {
        _cleanup_close_ int fd = -EBADF, dfd = -EBADF;
        _cleanup_free_ char *t = NULL;

        assert(dir_fd >= 0 || dir_fd == AT_FDCWD);
        assert(p);
        assert(IN_SET(operation & ~LOCK_NB, LOCK_EX, LOCK_SH));
        assert(ret);

        if (isempty(p))
                return -EINVAL;

        /* We use UNPOSIX locks as they have nice semantics, and are mostly compatible with NFS. */

        dfd = fd_reopen(dir_fd, O_CLOEXEC|O_PATH|O_DIRECTORY);
        if (dfd < 0)
                return dfd;

        t = strdup(p);
        if (!t)
                return -ENOMEM;

        fd = xopenat_lock_full(dfd,
                               p,
                               O_CREAT|O_RDWR|O_NOFOLLOW|O_CLOEXEC|O_NOCTTY,
                               /* xopen_flags = */ 0,
                               0600,
                               LOCK_UNPOSIX,
                               operation);
        if (fd < 0)
                return fd == -EAGAIN ? -EBUSY : fd;

        *ret = (LockFile) {
                .dir_fd = TAKE_FD(dfd),
                .path = TAKE_PTR(t),
                .fd = TAKE_FD(fd),
                .operation = operation,
        };

        return 0;
}

int make_lock_file_for(const char *p, int operation, LockFile *ret) {
        _cleanup_free_ char *fn = NULL, *dn = NULL, *t = NULL;
        int r;

        assert(p);
        assert(ret);

        r = path_extract_filename(p, &fn);
        if (r < 0)
                return r;

        r = path_extract_directory(p, &dn);
        if (r < 0)
                return r;

        t = strjoin(dn, "/.#", fn, ".lck");
        if (!t)
                return -ENOMEM;

        return make_lock_file(t, operation, ret);
}

void release_lock_file(LockFile *f) {
        if (!f)
                return;

        if (f->path) {

                /* If we are the exclusive owner we can safely delete
                 * the lock file itself. If we are not the exclusive
                 * owner, we can try becoming it. */

                if (f->fd >= 0 &&
                    (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)
                        (void) unlinkat(f->dir_fd, f->path, 0);

                f->path = mfree(f->path);
        }

        f->dir_fd = safe_close(f->dir_fd);
        f->fd = safe_close(f->fd);
        f->operation = 0;
}

static int fcntl_lock(int fd, int operation, bool ofd) {
        int cmd, type, r;

        assert(fd >= 0);

        if (ofd)
                cmd = (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW;
        else
                cmd = (operation & LOCK_NB) ? F_SETLK : F_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 we are doing non-blocking operations, treat EACCES/EAGAIN the same as per man page. But if
         * not, propagate EACCES back, as it will likely be due to an LSM denying the operation (for example
         * LXC with AppArmor when running on kernel < 6.2), and in some cases we want to gracefully
         * fallback (e.g.: PrivateNetwork=yes). As per documentation, it's only the non-blocking operation
         * F_SETLK that might return EACCES on some platforms (although the Linux implementation doesn't
         * seem to), as F_SETLKW and F_OFD_SETLKW block so this is not an issue, and F_OFD_SETLK is documented
         * to only return EAGAIN if the lock is already held. */
        if ((operation & LOCK_NB) && r == -EACCES)
                r = -EAGAIN;

        return r;
}

int posix_lock(int fd, int operation) {
        return fcntl_lock(fd, operation, /*ofd=*/ false);
}

int unposix_lock(int fd, int operation) {
        return fcntl_lock(fd, operation, /*ofd=*/ true);
}

void posix_unlockpp(int **fd) {
        assert(fd);

        if (!*fd || **fd < 0)
                return;

        (void) fcntl_lock(**fd, LOCK_UN, /*ofd=*/ false);
        *fd = NULL;
}

void unposix_unlockpp(int **fd) {
        assert(fd);

        if (!*fd || **fd < 0)
                return;

        (void) fcntl_lock(**fd, LOCK_UN, /*ofd=*/ true);
        *fd = NULL;
}

int lock_generic(int fd, LockType type, int operation) {
        assert(fd >= 0);

        switch (type) {
        case LOCK_NONE:
                return 0;
        case LOCK_BSD:
                return RET_NERRNO(flock(fd, operation));
        case LOCK_POSIX:
                return posix_lock(fd, operation);
        case LOCK_UNPOSIX:
                return unposix_lock(fd, operation);
        default:
                assert_not_reached();
        }
}

int lock_generic_with_timeout(int fd, LockType type, int operation, usec_t timeout) {
        _cleanup_(sigkill_waitp) pid_t pid = 0;
        int r;

        assert(fd >= 0);

        /* A version of lock_generic(), but with a timeout. We do this in a child process, since the kernel
         * APIs natively don't support a timeout. We set a SIGALRM timer that will kill the child after the
         * timeout is hit. Returns -ETIMEDOUT if the timeout is hit, and 0 on success.
         *
         * This only works for BSD and UNPOSIX locks, as only those are fd-bound, and hence can be acquired
         * from any process that has access to the fd. POSIX locks OTOH are process-bound, and hence if we'd
         * acquire them in a child process they'd remain unlocked in the parent. */

        if (type == LOCK_NONE)
                return 0;
        if (!IN_SET(type, LOCK_BSD, LOCK_UNPOSIX)) /* Not for POSIX locks, see above. */
                return -EOPNOTSUPP;

        /* First, try without forking anything off */
        r = lock_generic(fd, type, operation | (timeout == USEC_INFINITY ? 0 : LOCK_NB));
        if (r != -EAGAIN || timeout == 0 || FLAGS_SET(operation, LOCK_NB))
                return r;

        /* If that didn't work, try with a child */

        r = safe_fork("(sd-flock)", FORK_RESET_SIGNALS|FORK_DEATHSIG_SIGKILL, &pid);
        if (r < 0)
                return log_error_errno(r, "Failed to flock block device in child process: %m");
        if (r == 0) {
                struct sigevent sev = {
                        .sigev_notify = SIGEV_SIGNAL,
                        .sigev_signo = SIGALRM,
                };
                timer_t id;

                if (timer_create(CLOCK_MONOTONIC, &sev, &id) < 0) {
                        log_error_errno(errno, "Failed to allocate CLOCK_MONOTONIC timer: %m");
                        _exit(EXIT_FAILURE);
                }

                struct itimerspec its = {};
                timespec_store(&its.it_value, timeout);

                if (timer_settime(id, /* flags= */ 0, &its, NULL) < 0) {
                        log_error_errno(errno, "Failed to start CLOCK_MONOTONIC timer: %m");
                        _exit(EXIT_FAILURE);
                }

                if (lock_generic(fd, type, operation) < 0) {
                        log_error_errno(errno, "Unable to get an exclusive lock on the device: %m");
                        _exit(EXIT_FAILURE);
                }

                _exit(EXIT_SUCCESS);
        }

        siginfo_t status;
        r = wait_for_terminate(pid, &status);
        if (r < 0)
                return r;

        TAKE_PID(pid);

        switch (status.si_code) {

        case CLD_EXITED:
                if (status.si_status != EXIT_SUCCESS)
                        return -EPROTO;

                return 0;

        case CLD_KILLED:
                if (status.si_status == SIGALRM)
                        return -ETIMEDOUT;

                _fallthrough_;

        case CLD_DUMPED:
                return -EPROTO;

        default:
                assert_not_reached();
        }
}

1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3	#include <errno.h>
4	#include <fcntl.h>
5	#include <signal.h>
6	#include <stdio.h>
7	#include <string.h>
8	#include <sys/file.h>
9	#include <sys/stat.h>
10	#include <sys/wait.h>
11
12	#include "alloc-util.h"
13	#include "errno-util.h"
14	#include "fd-util.h"
15	#include "fs-util.h"
16	#include "lock-util.h"
17	#include "log.h"
18	#include "macro.h"
19	#include "missing_fcntl.h"
20	#include "path-util.h"
21	#include "process-util.h"
22
23	int make_lock_file_at(int dir_fd, const char p, int operation, LockFile ret) {	243,415✔
24	_cleanup_close_ int fd = -EBADF, dfd = -EBADF;	243,415✔
25	_cleanup_free_ char *t = NULL;	243,415✔
26
27	assert(dir_fd >= 0 \|\| dir_fd == AT_FDCWD);	243,415✔
28	assert(p);	243,415✔
29	assert(IN_SET(operation & ~LOCK_NB, LOCK_EX, LOCK_SH));	243,415✔
30	assert(ret);	243,415✔
31
32	if (isempty(p))	486,830✔
33	return -EINVAL;
34
35	/* We use UNPOSIX locks as they have nice semantics, and are mostly compatible with NFS. */
36
37	dfd = fd_reopen(dir_fd, O_CLOEXEC\|O_PATH\|O_DIRECTORY);	243,415✔
38	if (dfd < 0)	243,415✔
39	return dfd;
40
41	t = strdup(p);	243,415✔
42	if (!t)	243,415✔
43	return -ENOMEM;
44
45	fd = xopenat_lock_full(dfd,	243,415✔
46	p,
47	O_CREAT\|O_RDWR\|O_NOFOLLOW\|O_CLOEXEC\|O_NOCTTY,
48	/* xopen_flags = */ 0,
49	0600,
50	LOCK_UNPOSIX,
51	operation);
52	if (fd < 0)	243,415✔
53	return fd == -EAGAIN ? -EBUSY : fd;	3✔
54
55	*ret = (LockFile) {	243,412✔
56	.dir_fd = TAKE_FD(dfd),	243,412✔
57	.path = TAKE_PTR(t),	243,412✔
58	.fd = TAKE_FD(fd),	243,412✔
59	.operation = operation,
60	};
61
62	return 0;	243,412✔
63	}
64
65	int make_lock_file_for(const char p, int operation, LockFile ret) {	616✔
66	_cleanup_free_ char fn = NULL, dn = NULL, *t = NULL;	616✔
67	int r;	616✔
68
69	assert(p);	616✔
70	assert(ret);	616✔
71
72	r = path_extract_filename(p, &fn);	616✔
73	if (r < 0)	616✔
74	return r;
75
76	r = path_extract_directory(p, &dn);	616✔
77	if (r < 0)	616✔
78	return r;
79
80	t = strjoin(dn, "/.#", fn, ".lck");	616✔
81	if (!t)	616✔
82	return -ENOMEM;
83
84	return make_lock_file(t, operation, ret);	616✔
85	}
86
87	void release_lock_file(LockFile *f) {	486,203✔
88	if (!f)	486,203✔
89	return;
90
91	if (f->path) {	486,203✔
92
93	/* If we are the exclusive owner we can safely delete
94	* the lock file itself. If we are not the exclusive
95	* owner, we can try becoming it. */
96
97	if (f->fd >= 0 &&	243,001✔
98	(f->operation & ~LOCK_NB) == LOCK_SH &&	243,449✔
99	unposix_lock(f->fd, LOCK_EX\|LOCK_NB) >= 0)	448✔
100	f->operation = LOCK_EX\|LOCK_NB;	447✔
101
102	if ((f->operation & ~LOCK_NB) == LOCK_EX)	243,001✔
103	(void) unlinkat(f->dir_fd, f->path, 0);	243,000✔
104
105	f->path = mfree(f->path);	243,001✔
106	}
107
108	f->dir_fd = safe_close(f->dir_fd);	486,203✔
109	f->fd = safe_close(f->fd);	486,203✔
110	f->operation = 0;	486,203✔
111	}
112
113	static int fcntl_lock(int fd, int operation, bool ofd) {	263,574✔
114	int cmd, type, r;	263,574✔
115
116	assert(fd >= 0);	263,574✔
117
118	if (ofd)	263,574✔
119	cmd = (operation & LOCK_NB) ? F_OFD_SETLK : F_OFD_SETLKW;	263,173✔
120	else
121	cmd = (operation & LOCK_NB) ? F_SETLK : F_SETLKW;	401✔
122
123	switch (operation & ~LOCK_NB) {	263,574✔
124	case LOCK_EX:
125	type = F_WRLCK;
126	break;
127	case LOCK_SH:	484✔
128	type = F_RDLCK;	484✔
129	break;	484✔
130	case LOCK_UN:	200✔
131	type = F_UNLCK;	200✔
132	break;	200✔
133	default:	×
UNCOV 134	assert_not_reached();	×
135	}
136
137	r = RET_NERRNO(fcntl(fd, cmd, &(struct flock) {	263,574✔
138	.l_type = type,
139	.l_whence = SEEK_SET,
140	.l_start = 0,
141	.l_len = 0,
142	}));
143
144	/* If we are doing non-blocking operations, treat EACCES/EAGAIN the same as per man page. But if
145	* not, propagate EACCES back, as it will likely be due to an LSM denying the operation (for example
146	* LXC with AppArmor when running on kernel < 6.2), and in some cases we want to gracefully
147	* fallback (e.g.: PrivateNetwork=yes). As per documentation, it's only the non-blocking operation
148	* F_SETLK that might return EACCES on some platforms (although the Linux implementation doesn't
149	* seem to), as F_SETLKW and F_OFD_SETLKW block so this is not an issue, and F_OFD_SETLK is documented
150	* to only return EAGAIN if the lock is already held. */
151	if ((operation & LOCK_NB) && r == -EACCES)	263,574✔
UNCOV 152	r = -EAGAIN;	×
153
154	return r;	263,574✔
155	}
156
157	int posix_lock(int fd, int operation) {	257✔
158	return fcntl_lock(fd, operation, /ofd=/ false);	257✔
159	}
160
161	int unposix_lock(int fd, int operation) {	263,173✔
162	return fcntl_lock(fd, operation, /ofd=/ true);	263,173✔
163	}
164
165	void posix_unlockpp(int **fd) {	144✔
166	assert(fd);	144✔
167
168	if (!fd \|\| *fd < 0)	144✔
169	return;
170
171	(void) fcntl_lock(*fd, LOCK_UN, /ofd=*/ false);	144✔
172	*fd = NULL;	144✔
173	}
174
175	void unposix_unlockpp(int **fd) {	×
UNCOV 176	assert(fd);	×
177
UNCOV 178	if (!fd \|\| *fd < 0)	×
179	return;
180
181	(void) fcntl_lock(*fd, LOCK_UN, /ofd=*/ true);	×
UNCOV 182	*fd = NULL;	×
183	}
184
185	int lock_generic(int fd, LockType type, int operation) {	300,031✔
186	assert(fd >= 0);	300,031✔
187
188	switch (type) {	300,031✔
189	case LOCK_NONE:
190	return 0;
191	case LOCK_BSD:	3,142✔
192	return RET_NERRNO(flock(fd, operation));	3,142✔
193	case LOCK_POSIX:	1✔
194	return posix_lock(fd, operation);	1✔
195	case LOCK_UNPOSIX:	262,444✔
196	return unposix_lock(fd, operation);	262,444✔
197	default:	×
UNCOV 198	assert_not_reached();	×
199	}
200	}
201
202	int lock_generic_with_timeout(int fd, LockType type, int operation, usec_t timeout) {	535✔
203	_cleanup_(sigkill_waitp) pid_t pid = 0;	535✔
204	int r;	535✔
205
206	assert(fd >= 0);	535✔
207
208	/* A version of lock_generic(), but with a timeout. We do this in a child process, since the kernel
209	* APIs natively don't support a timeout. We set a SIGALRM timer that will kill the child after the
210	* timeout is hit. Returns -ETIMEDOUT if the timeout is hit, and 0 on success.
211	*
212	* This only works for BSD and UNPOSIX locks, as only those are fd-bound, and hence can be acquired
213	* from any process that has access to the fd. POSIX locks OTOH are process-bound, and hence if we'd
214	* acquire them in a child process they'd remain unlocked in the parent. */
215
216	if (type == LOCK_NONE)	535✔
217	return 0;
218	if (!IN_SET(type, LOCK_BSD, LOCK_UNPOSIX)) /* Not for POSIX locks, see above. */	535✔
219	return -EOPNOTSUPP;
220
221	/* First, try without forking anything off */
222	r = lock_generic(fd, type, operation \| (timeout == USEC_INFINITY ? 0 : LOCK_NB));	1,070✔
223	if (r != -EAGAIN \|\| timeout == 0 \|\| FLAGS_SET(operation, LOCK_NB))	535✔
224	return r;
225
226	/* If that didn't work, try with a child */
227
228	r = safe_fork("(sd-flock)", FORK_RESET_SIGNALS\|FORK_DEATHSIG_SIGKILL, &pid);	525✔
229	if (r < 0)	1,048✔
UNCOV 230	return log_error_errno(r, "Failed to flock block device in child process: %m");	×
231	if (r == 0) {	1,048✔
232	struct sigevent sev = {	523✔
233	.sigev_notify = SIGEV_SIGNAL,
234	.sigev_signo = SIGALRM,
235	};
236	timer_t id;	523✔
237
238	if (timer_create(CLOCK_MONOTONIC, &sev, &id) < 0) {	523✔
239	log_error_errno(errno, "Failed to allocate CLOCK_MONOTONIC timer: %m");	×
UNCOV 240	_exit(EXIT_FAILURE);	×
241	}
242
243	struct itimerspec its = {};	523✔
244	timespec_store(&its.it_value, timeout);	523✔
245
246	if (timer_settime(id, /* flags= */ 0, &its, NULL) < 0) {	523✔
247	log_error_errno(errno, "Failed to start CLOCK_MONOTONIC timer: %m");	×
UNCOV 248	_exit(EXIT_FAILURE);	×
249	}
250
251	if (lock_generic(fd, type, operation) < 0) {	523✔
252	log_error_errno(errno, "Unable to get an exclusive lock on the device: %m");	×
UNCOV 253	_exit(EXIT_FAILURE);	×
254	}
255
256	_exit(EXIT_SUCCESS);	523✔
257	}
258
259	siginfo_t status;	525✔
260	r = wait_for_terminate(pid, &status);	525✔
261	if (r < 0)	525✔
262	return r;
263
264	TAKE_PID(pid);	525✔
265
266	switch (status.si_code) {	525✔
267
268	case CLD_EXITED:	523✔
269	if (status.si_status != EXIT_SUCCESS)	523✔
UNCOV 270	return -EPROTO;	×
271
272	return 0;
273
274	case CLD_KILLED:	2✔
275	if (status.si_status == SIGALRM)	2✔
276	return -ETIMEDOUT;	2✔
277
278	_fallthrough_;
279
280	case CLD_DUMPED:
281	return -EPROTO;
282
283	default:	×
UNCOV 284	assert_not_reached();	×
285	}
286	}

systemd / systemd / 14895667988

Source File Press 'n' to go to next uncovered line, 'b' for previous

Source File
Press 'n' to go to next uncovered line, 'b' for previous