]>
git.ipfire.org Git - thirdparty/systemd.git/blob - src/basic/io-util.c
1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
9 #include "string-util.h"
10 #include "time-util.h"
12 int flush_fd(int fd
) {
15 /* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
16 * read. Note that some file descriptors (notable IP sockets) will trigger POLLIN even when no data can be read
17 * (due to IP packet checksum mismatches), hence this function is only safe to be non-blocking if the fd used
18 * was set to non-blocking too. */
25 r
= fd_wait_for_event(fd
, POLLIN
, 0);
35 l
= read(fd
, buf
, sizeof(buf
));
51 ssize_t
loop_read(int fd
, void *buf
, size_t nbytes
, bool do_poll
) {
58 /* If called with nbytes == 0, let's call read() at least
59 * once, to validate the operation */
61 if (nbytes
> (size_t) SSIZE_MAX
)
67 k
= read(fd
, p
, nbytes
);
72 if (errno
== EAGAIN
&& do_poll
) {
74 /* We knowingly ignore any return value here,
75 * and expect that any error/EOF is reported
78 (void) fd_wait_for_event(fd
, POLLIN
, USEC_INFINITY
);
82 return n
> 0 ? n
: -errno
;
88 assert((size_t) k
<= nbytes
);
98 int loop_read_exact(int fd
, void *buf
, size_t nbytes
, bool do_poll
) {
101 n
= loop_read(fd
, buf
, nbytes
, do_poll
);
104 if ((size_t) n
!= nbytes
)
110 int loop_write(int fd
, const void *buf
, size_t nbytes
, bool do_poll
) {
111 const uint8_t *p
= buf
;
116 if (_unlikely_(nbytes
> (size_t) SSIZE_MAX
))
122 k
= write(fd
, p
, nbytes
);
127 if (errno
== EAGAIN
&& do_poll
) {
128 /* We knowingly ignore any return value here,
129 * and expect that any error/EOF is reported
132 (void) fd_wait_for_event(fd
, POLLOUT
, USEC_INFINITY
);
139 if (_unlikely_(nbytes
> 0 && k
== 0)) /* Can't really happen */
142 assert((size_t) k
<= nbytes
);
146 } while (nbytes
> 0);
151 int pipe_eof(int fd
) {
154 r
= fd_wait_for_event(fd
, POLLIN
, 0);
158 return !!(r
& POLLHUP
);
161 int ppoll_usec(struct pollfd
*fds
, size_t nfds
, usec_t timeout
) {
165 assert(fds
|| nfds
== 0);
170 r
= ppoll(fds
, nfds
, timeout
== USEC_INFINITY
? NULL
: timespec_store(&ts
, timeout
), NULL
);
176 for (size_t i
= 0, n
= r
; i
< nfds
&& n
> 0; i
++) {
177 if (fds
[i
].revents
== 0)
179 if (fds
[i
].revents
& POLLNVAL
)
187 int fd_wait_for_event(int fd
, int event
, usec_t timeout
) {
188 struct pollfd pollfd
= {
194 r
= ppoll_usec(&pollfd
, 1, timeout
);
198 return pollfd
.revents
;
201 static size_t nul_length(const uint8_t *p
, size_t sz
) {
216 ssize_t
sparse_write(int fd
, const void *p
, size_t sz
, size_t run_length
) {
217 const uint8_t *q
, *w
, *e
;
225 n
= nul_length(q
, e
- q
);
227 /* If there are more than the specified run length of
228 * NUL bytes, or if this is the beginning or the end
229 * of the buffer, then seek instead of write */
230 if ((n
> run_length
) ||
232 (n
> 0 && q
+ n
>= e
)) {
234 l
= write(fd
, w
, q
- w
);
241 if (lseek(fd
, n
, SEEK_CUR
) == (off_t
) -1)
253 l
= write(fd
, w
, q
- w
);
260 return q
- (const uint8_t*) p
;
263 char* set_iovec_string_field(struct iovec
*iovec
, size_t *n_iovec
, const char *field
, const char *value
) {
266 x
= strjoin(field
, value
);
268 iovec
[(*n_iovec
)++] = IOVEC_MAKE_STRING(x
);
272 char* set_iovec_string_field_free(struct iovec
*iovec
, size_t *n_iovec
, const char *field
, char *value
) {
275 x
= set_iovec_string_field(iovec
, n_iovec
, field
, value
);
280 struct iovec_wrapper
*iovw_new(void) {
281 return malloc0(sizeof(struct iovec_wrapper
));
284 void iovw_free_contents(struct iovec_wrapper
*iovw
, bool free_vectors
) {
286 for (size_t i
= 0; i
< iovw
->count
; i
++)
287 free(iovw
->iovec
[i
].iov_base
);
289 iovw
->iovec
= mfree(iovw
->iovec
);
293 struct iovec_wrapper
*iovw_free_free(struct iovec_wrapper
*iovw
) {
294 iovw_free_contents(iovw
, true);
299 struct iovec_wrapper
*iovw_free(struct iovec_wrapper
*iovw
) {
300 iovw_free_contents(iovw
, false);
305 int iovw_put(struct iovec_wrapper
*iovw
, void *data
, size_t len
) {
306 if (iovw
->count
>= IOV_MAX
)
309 if (!GREEDY_REALLOC(iovw
->iovec
, iovw
->count
+ 1))
312 iovw
->iovec
[iovw
->count
++] = IOVEC_MAKE(data
, len
);
316 int iovw_put_string_field(struct iovec_wrapper
*iovw
, const char *field
, const char *value
) {
317 _cleanup_free_
char *x
= NULL
;
320 x
= strjoin(field
, value
);
324 r
= iovw_put(iovw
, x
, strlen(x
));
331 int iovw_put_string_field_free(struct iovec_wrapper
*iovw
, const char *field
, char *value
) {
332 _cleanup_free_ _unused_
char *free_ptr
= value
;
334 return iovw_put_string_field(iovw
, field
, value
);
337 void iovw_rebase(struct iovec_wrapper
*iovw
, char *old
, char *new) {
338 for (size_t i
= 0; i
< iovw
->count
; i
++)
339 iovw
->iovec
[i
].iov_base
= (char *)iovw
->iovec
[i
].iov_base
- old
+ new;
342 size_t iovw_size(struct iovec_wrapper
*iovw
) {
345 for (size_t i
= 0; i
< iovw
->count
; i
++)
346 n
+= iovw
->iovec
[i
].iov_len
;