15263807472

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

#include <poll.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include "errno-util.h"
#include "io-util.h"
#include "time-util.h"

int flush_fd(int fd) {
        int count = 0;

        /* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
         * read. Note that some file descriptors (notable IP sockets) will trigger POLLIN even when no data can be read
         * (due to IP packet checksum mismatches), hence this function is only safe to be non-blocking if the fd used
         * was set to non-blocking too. */

        for (;;) {
                char buf[LINE_MAX];
                ssize_t l;
                int r;

                r = fd_wait_for_event(fd, POLLIN, 0);
                if (r < 0) {
                        if (r == -EINTR)
                                continue;

                        return r;
                }
                if (r == 0)
                        return count;

                l = read(fd, buf, sizeof(buf));
                if (l < 0) {
                        if (errno == EINTR)
                                continue;

                        if (errno == EAGAIN)
                                return count;

                        return -errno;
                } else if (l == 0)
                        return count;

                count += (int) l;
        }
}

ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
        uint8_t *p = ASSERT_PTR(buf);
        ssize_t n = 0;

        assert(fd >= 0);

        /* If called with nbytes == 0, let's call read() at least once, to validate the operation */

        if (nbytes > (size_t) SSIZE_MAX)
                return -EINVAL;

        do {
                ssize_t k;

                k = read(fd, p, nbytes);
                if (k < 0) {
                        if (errno == EINTR)
                                continue;

                        if (errno == EAGAIN && do_poll) {

                                /* We knowingly ignore any return value here,
                                 * and expect that any error/EOF is reported
                                 * via read() */

                                (void) fd_wait_for_event(fd, POLLIN, USEC_INFINITY);
                                continue;
                        }

                        return n > 0 ? n : -errno;
                }

                if (k == 0)
                        return n;

                assert((size_t) k <= nbytes);
                assert(k <= SSIZE_MAX - n);

                p += k;
                nbytes -= k;
                n += k;
        } while (nbytes > 0);

        return n;
}

int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {
        ssize_t n;

        n = loop_read(fd, buf, nbytes, do_poll);
        if (n < 0)
                return (int) n;
        if ((size_t) n != nbytes)
                return -EIO;

        return 0;
}

int loop_write_full(int fd, const void *buf, size_t nbytes, usec_t timeout) {
        const uint8_t *p;
        usec_t end;
        int r;

        assert(fd >= 0);
        assert(buf || nbytes == 0);

        if (nbytes == 0) {
                static const dummy_t dummy[0];
                assert_cc(sizeof(dummy) == 0);
                p = (const void*) dummy; /* Some valid pointer, in case NULL was specified */
        } else {
                if (nbytes == SIZE_MAX)
                        nbytes = strlen(buf);
                else if (_unlikely_(nbytes > (size_t) SSIZE_MAX))
                        return -EINVAL;

                p = buf;
        }

        /* When timeout is 0 or USEC_INFINITY this is not used. But we initialize it to a sensible value. */
        end = timestamp_is_set(timeout) ? usec_add(now(CLOCK_MONOTONIC), timeout) : USEC_INFINITY;

        do {
                ssize_t k;

                k = write(fd, p, nbytes);
                if (k < 0) {
                        if (errno == EINTR)
                                continue;

                        if (errno != EAGAIN || timeout == 0)
                                return -errno;

                        usec_t wait_for;

                        if (timeout == USEC_INFINITY)
                                wait_for = USEC_INFINITY;
                        else {
                                usec_t t = now(CLOCK_MONOTONIC);
                                if (t >= end)
                                        return -ETIME;

                                wait_for = usec_sub_unsigned(end, t);
                        }

                        r = fd_wait_for_event(fd, POLLOUT, wait_for);
                        if (timeout == USEC_INFINITY || ERRNO_IS_NEG_TRANSIENT(r))
                                /* If timeout == USEC_INFINITY we knowingly ignore any return value
                                 * here, and expect that any error/EOF is reported via write() */
                                continue;
                        if (r < 0)
                                return r;
                        if (r == 0)
                                return -ETIME;
                        continue;
                }

                if (_unlikely_(nbytes > 0 && k == 0)) /* Can't really happen */
                        return -EIO;

                assert((size_t) k <= nbytes);

                p += k;
                nbytes -= k;
        } while (nbytes > 0);

        return 0;
}

int pipe_eof(int fd) {
        int r;

        r = fd_wait_for_event(fd, POLLIN, 0);
        if (r <= 0)
                return r;

        return !!(r & POLLHUP);
}

int ppoll_usec_full(struct pollfd *fds, size_t nfds, usec_t timeout, const sigset_t *ss) {
        int r;

        assert(fds || nfds == 0);

        /* This is a wrapper around ppoll() that does primarily two things:
         *
         *  ✅ Takes a usec_t instead of a struct timespec
         *
         *  ✅ Guarantees that if an invalid fd is specified we return EBADF (i.e. converts POLLNVAL to
         *     EBADF). This is done because EBADF is a programming error usually, and hence should bubble up
         *     as error, and not be eaten up as non-error POLLNVAL event.
         *
         *  ⚠️ ⚠️ ⚠️ Note that this function does not add any special handling for EINTR. Don't forget
         *  poll()/ppoll() will return with EINTR on any received signal always, there is no automatic
         *  restarting via SA_RESTART available. Thus, typically you want to handle EINTR not as an error,
         *  but just as reason to restart things, under the assumption you use a more appropriate mechanism
         *  to handle signals, such as signalfd() or signal handlers. ⚠️ ⚠️ ⚠️
         */

        if (nfds == 0 && timeout == 0)
                return 0;

        r = ppoll(fds, nfds, timeout == USEC_INFINITY ? NULL : TIMESPEC_STORE(timeout), ss);
        if (r < 0)
                return -errno;
        if (r == 0)
                return 0;

        for (size_t i = 0, n = r; i < nfds && n > 0; i++) {
                if (fds[i].revents == 0)
                        continue;
                if (fds[i].revents & POLLNVAL)
                        return -EBADF;
                n--;
        }

        return r;
}

int fd_wait_for_event(int fd, int event, usec_t timeout) {
        struct pollfd pollfd = {
                .fd = fd,
                .events = event,
        };
        int r;

        /* ⚠️ ⚠️ ⚠️ Keep in mind you almost certainly want to handle -EINTR gracefully in the caller, see
         * ppoll_usec() above! ⚠️ ⚠️ ⚠️ */

        r = ppoll_usec(&pollfd, 1, timeout);
        if (r <= 0)
                return r;

        return pollfd.revents;
}

static size_t nul_length(const uint8_t *p, size_t sz) {
        size_t n = 0;

        while (sz > 0) {
                if (*p != 0)
                        break;

                n++;
                p++;
                sz--;
        }

        return n;
}

ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
        const uint8_t *q, *w, *e;
        ssize_t l;

        q = w = p;
        e = q + sz;
        while (q < e) {
                size_t n;

                n = nul_length(q, e - q);

                /* If there are more than the specified run length of
                 * NUL bytes, or if this is the beginning or the end
                 * of the buffer, then seek instead of write */
                if ((n > run_length) ||
                    (n > 0 && q == p) ||
                    (n > 0 && q + n >= e)) {
                        if (q > w) {
                                l = write(fd, w, q - w);
                                if (l < 0)
                                        return -errno;
                                if (l != q -w)
                                        return -EIO;
                        }

                        if (lseek(fd, n, SEEK_CUR) < 0)
                                return -errno;

                        q += n;
                        w = q;
                } else if (n > 0)
                        q += n;
                else
                        q++;
        }

        if (q > w) {
                l = write(fd, w, q - w);
                if (l < 0)
                        return -errno;
                if (l != q - w)
                        return -EIO;
        }

        return q - (const uint8_t*) p;
}

1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
2
3	#include <poll.h>
4	#include <stdio.h>
5	#include <string.h>
6	#include <time.h>
7	#include <unistd.h>
8
9	#include "errno-util.h"
10	#include "io-util.h"
11	#include "time-util.h"
12
13	int flush_fd(int fd) {	3,658✔
14	int count = 0;	3,658✔
15
16	/* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
17	* read. Note that some file descriptors (notable IP sockets) will trigger POLLIN even when no data can be read
18	* (due to IP packet checksum mismatches), hence this function is only safe to be non-blocking if the fd used
19	* was set to non-blocking too. */
20
21	for (;;) {	6,635✔
22	char buf[LINE_MAX];	6,635✔
23	ssize_t l;	6,635✔
24	int r;	6,635✔
25
26	r = fd_wait_for_event(fd, POLLIN, 0);	6,635✔
27	if (r < 0) {	6,635✔
UNCOV 28	if (r == -EINTR)	×
29	continue;	×
30
31	return r;	3,658✔
32	}
33	if (r == 0)	6,635✔
34	return count;
35
36	l = read(fd, buf, sizeof(buf));	2,977✔
37	if (l < 0) {	2,977✔
UNCOV 38	if (errno == EINTR)	×
39	continue;	×
40
UNCOV 41	if (errno == EAGAIN)	×
42	return count;
43
UNCOV 44	return -errno;	×
45	} else if (l == 0)	2,977✔
46	return count;
47
48	count += (int) l;	2,977✔
49	}
50	}
51
52	ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {	13,035✔
53	uint8_t *p = ASSERT_PTR(buf);	13,035✔
54	ssize_t n = 0;	13,035✔
55
56	assert(fd >= 0);	13,035✔
57
58	/* If called with nbytes == 0, let's call read() at least once, to validate the operation */
59
60	if (nbytes > (size_t) SSIZE_MAX)	13,035✔
61	return -EINVAL;
62
63	do {	24,302✔
64	ssize_t k;	24,302✔
65
66	k = read(fd, p, nbytes);	24,302✔
67	if (k < 0) {	24,302✔
UNCOV 68	if (errno == EINTR)	×
69	continue;	×
70
UNCOV 71	if (errno == EAGAIN && do_poll) {	×
72
73	/* We knowingly ignore any return value here,
74	* and expect that any error/EOF is reported
75	* via read() */
76
UNCOV 77	(void) fd_wait_for_event(fd, POLLIN, USEC_INFINITY);	×
78	continue;	×
79	}
80
UNCOV 81	return n > 0 ? n : -errno;	×
82	}
83
84	if (k == 0)	24,302✔
85	return n;
86
87	assert((size_t) k <= nbytes);	12,939✔
88	assert(k <= SSIZE_MAX - n);	12,939✔
89
90	p += k;	12,939✔
91	nbytes -= k;	12,939✔
92	n += k;	12,939✔
93	} while (nbytes > 0);	12,939✔
94
95	return n;
96	}
97
98	int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {	1,447✔
99	ssize_t n;	1,447✔
100
101	n = loop_read(fd, buf, nbytes, do_poll);	1,447✔
102	if (n < 0)	1,447✔
UNCOV 103	return (int) n;	×
104	if ((size_t) n != nbytes)	1,447✔
UNCOV 105	return -EIO;	×
106
107	return 0;
108	}
109
110	int loop_write_full(int fd, const void *buf, size_t nbytes, usec_t timeout) {	40,657✔
111	const uint8_t *p;	40,657✔
112	usec_t end;	40,657✔
113	int r;	40,657✔
114
115	assert(fd >= 0);	40,657✔
116	assert(buf \|\| nbytes == 0);	40,657✔
117
118	if (nbytes == 0) {	40,657✔
119	static const dummy_t dummy[0];
120	assert_cc(sizeof(dummy) == 0);
121	p = (const void) dummy; / Some valid pointer, in case NULL was specified */
122	} else {
123	if (nbytes == SIZE_MAX)	40,631✔
124	nbytes = strlen(buf);	404✔
125	else if (_unlikely_(nbytes > (size_t) SSIZE_MAX))	40,227✔
126	return -EINVAL;
127
128	p = buf;
129	}
130
131	/* When timeout is 0 or USEC_INFINITY this is not used. But we initialize it to a sensible value. */
132	end = timestamp_is_set(timeout) ? usec_add(now(CLOCK_MONOTONIC), timeout) : USEC_INFINITY;	40,744✔
133
134	do {	40,657✔
135	ssize_t k;	40,657✔
136
137	k = write(fd, p, nbytes);	40,657✔
138	if (k < 0) {	40,657✔
139	if (errno == EINTR)	1✔
UNCOV 140	continue;	×
141
142	if (errno != EAGAIN \|\| timeout == 0)	1✔
143	return -errno;	1✔
144
UNCOV 145	usec_t wait_for;	×
146
UNCOV 147	if (timeout == USEC_INFINITY)	×
148	wait_for = USEC_INFINITY;
149	else {
UNCOV 150	usec_t t = now(CLOCK_MONOTONIC);	×
151	if (t >= end)	×
152	return -ETIME;
153
UNCOV 154	wait_for = usec_sub_unsigned(end, t);	×
155	}
156
UNCOV 157	r = fd_wait_for_event(fd, POLLOUT, wait_for);	×
158	if (timeout == USEC_INFINITY \|\| ERRNO_IS_NEG_TRANSIENT(r))	×
159	/* If timeout == USEC_INFINITY we knowingly ignore any return value
160	* here, and expect that any error/EOF is reported via write() */
UNCOV 161	continue;	×
162	if (r < 0)	×
163	return r;
UNCOV 164	if (r == 0)	×
165	return -ETIME;
UNCOV 166	continue;	×
167	}
168
169	if (_unlikely_(nbytes > 0 && k == 0)) /* Can't really happen */	40,656✔
170	return -EIO;
171
172	assert((size_t) k <= nbytes);	40,656✔
173
174	p += k;	40,656✔
175	nbytes -= k;	40,656✔
176	} while (nbytes > 0);	40,656✔
177
178	return 0;
179	}
180
UNCOV 181	int pipe_eof(int fd) {	×
182	int r;	×
183
UNCOV 184	r = fd_wait_for_event(fd, POLLIN, 0);	×
185	if (r <= 0)	×
186	return r;
187
UNCOV 188	return !!(r & POLLHUP);	×
189	}
190
191	int ppoll_usec_full(struct pollfd fds, size_t nfds, usec_t timeout, const sigset_t ss) {	365,586✔
192	int r;	365,586✔
193
194	assert(fds \|\| nfds == 0);	365,586✔
195
196	/* This is a wrapper around ppoll() that does primarily two things:
197	*
198	* ✅ Takes a usec_t instead of a struct timespec
199	*
200	* ✅ Guarantees that if an invalid fd is specified we return EBADF (i.e. converts POLLNVAL to
201	* EBADF). This is done because EBADF is a programming error usually, and hence should bubble up
202	* as error, and not be eaten up as non-error POLLNVAL event.
203	*
204	* ⚠️ ⚠️ ⚠️ Note that this function does not add any special handling for EINTR. Don't forget
205	* poll()/ppoll() will return with EINTR on any received signal always, there is no automatic
206	* restarting via SA_RESTART available. Thus, typically you want to handle EINTR not as an error,
207	* but just as reason to restart things, under the assumption you use a more appropriate mechanism
208	* to handle signals, such as signalfd() or signal handlers. ⚠️ ⚠️ ⚠️
209	*/
210
211	if (nfds == 0 && timeout == 0)	365,586✔
212	return 0;	365,586✔
213
214	r = ppoll(fds, nfds, timeout == USEC_INFINITY ? NULL : TIMESPEC_STORE(timeout), ss);	365,586✔
215	if (r < 0)	365,586✔
UNCOV 216	return -errno;	×
217	if (r == 0)	365,586✔
218	return 0;
219
220	for (size_t i = 0, n = r; i < nfds && n > 0; i++) {	633,028✔
221	if (fds[i].revents == 0)	317,175✔
222	continue;	1,248✔
223	if (fds[i].revents & POLLNVAL)	315,927✔
224	return -EBADF;
225	n--;	315,927✔
226	}
227
228	return r;
229	}
230
231	int fd_wait_for_event(int fd, int event, usec_t timeout) {	65,966✔
232	struct pollfd pollfd = {	65,966✔
233	.fd = fd,
234	.events = event,
235	};
236	int r;	65,966✔
237
238	/* ⚠️ ⚠️ ⚠️ Keep in mind you almost certainly want to handle -EINTR gracefully in the caller, see
239	* ppoll_usec() above! ⚠️ ⚠️ ⚠️ */
240
241	r = ppoll_usec(&pollfd, 1, timeout);	65,966✔
242	if (r <= 0)	65,966✔
243	return r;	65,966✔
244
245	return pollfd.revents;	16,236✔
246	}
247
248	static size_t nul_length(const uint8_t *p, size_t sz) {	316,108,352✔
249	size_t n = 0;	316,108,352✔
250
251	while (sz > 0) {	570,189,932✔
252	if (*p != 0)	570,172,884✔
253	break;
254
255	n++;	254,081,580✔
256	p++;	254,081,580✔
257	sz--;	254,081,580✔
258	}
259
260	return n;	316,108,352✔
261	}
262
263	ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {	33,135✔
264	const uint8_t q, w, *e;	33,135✔
265	ssize_t l;	33,135✔
266
267	q = w = p;	33,135✔
268	e = q + sz;	33,135✔
269	while (q < e) {	316,141,487✔
270	size_t n;	316,108,352✔
271
272	n = nul_length(q, e - q);	316,108,352✔
273
274	/* If there are more than the specified run length of
275	* NUL bytes, or if this is the beginning or the end
276	* of the buffer, then seek instead of write */
277	if ((n > run_length) \|\|	316,108,352✔
278	(n > 0 && q == p) \|\|	315,941,486✔
279	(n > 0 && q + n >= e)) {	27,782,348✔
280	if (q > w) {	176,918✔
281	l = write(fd, w, q - w);	163,711✔
282	if (l < 0)	163,711✔
UNCOV 283	return -errno;	×
284	if (l != q -w)	163,711✔
285	return -EIO;
286	}
287
288	if (lseek(fd, n, SEEK_CUR) < 0)	176,918✔
UNCOV 289	return -errno;	×
290
291	q += n;	176,918✔
292	w = q;	176,918✔
293	} else if (n > 0)	27,776,033✔
294	q += n;
295	else
296	q++;	288,155,401✔
297	}
298
299	if (q > w) {	33,135✔
300	l = write(fd, w, q - w);	16,087✔
301	if (l < 0)	16,087✔
UNCOV 302	return -errno;	×
303	if (l != q - w)	16,087✔
304	return -EIO;
305	}
306
307	return q - (const uint8_t*) p;	33,135✔
308	}

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