1 /*
2  * Copyright (c) 2018, 2022 Stefan Sperling <stsp@openbsd.org>
3  *
4  * Permission to use, copy, modify, and distribute this software for any
5  * purpose with or without fee is hereby granted, provided that the above
6  * copyright notice and this permission notice appear in all copies.
7  *
8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15  */
16 
17 #include <errno.h>
18 #include <stdio.h>
19 #include <signal.h>
20 #include <poll.h>
21 #include <time.h>
22 #include <unistd.h>
23 
24 #include "got_error.h"
25 
26 #include "got_lib_poll.h"
27 
28 const struct got_error *
29 got_poll_fd(int fd, int events, int timeout)
30 {
31 	struct pollfd pfd[1];
32 	struct timespec ts;
33 	sigset_t sigset;
34 	int n;
35 
36 	pfd[0].fd = fd;
37 	pfd[0].events = events;
38 
39 	ts.tv_sec = timeout;
40 	ts.tv_nsec = 0;
41 
42 	if (sigemptyset(&sigset) == -1)
43 		return got_error_from_errno("sigemptyset");
44 	if (sigaddset(&sigset, SIGWINCH) == -1)
45 		return got_error_from_errno("sigaddset");
46 
47 	n = ppoll(pfd, 1, timeout == INFTIM ? NULL : &ts, &sigset);
48 	if (n == -1)
49 		return got_error_from_errno("ppoll");
50 	if (n == 0) {
51 		if (pfd[0].revents & POLLHUP)
52 			return got_error(GOT_ERR_EOF);
53 		return got_error(GOT_ERR_TIMEOUT);
54 	}
55 	if (pfd[0].revents & (POLLERR | POLLNVAL))
56 		return got_error_from_errno("poll error");
57 	if (pfd[0].revents & events)
58 		return NULL;
59 	if (pfd[0].revents & POLLHUP)
60 		return got_error(GOT_ERR_EOF);
61 
62 	return got_error(GOT_ERR_INTERRUPT);
63 }
64 
65 const struct got_error *
66 got_poll_read_full(int fd, size_t *len, void *buf, size_t bufsize,
67     size_t minbytes)
68 {
69 	const struct got_error *err = NULL;
70 	size_t have = 0;
71 	ssize_t r;
72 
73 	if (minbytes > bufsize)
74 		return got_error(GOT_ERR_NO_SPACE);
75 
76 	while (have < minbytes) {
77 		err = got_poll_fd(fd, POLLIN, INFTIM);
78 		if (err)
79 			return err;
80 		r = read(fd, buf + have, bufsize - have);
81 		if (r == -1)
82 			return got_error_from_errno("read");
83 		if (r == 0)
84 			return got_error(GOT_ERR_EOF);
85 		have += r;
86 	}
87 
88 	*len = have;
89 	return NULL;
90 }
91 
92 const struct got_error *
93 got_poll_write_full(int fd, const void *buf, off_t len)
94 {
95 	const struct got_error *err = NULL;
96 	off_t wlen = 0;
97 	ssize_t w = 0;
98 
99 	while (wlen != len) {
100 		if (wlen > 0) {
101 			err = got_poll_fd(fd, POLLOUT, INFTIM);
102 			if (err)
103 				return err;
104 		}
105 		w = write(fd, buf + wlen, len - wlen);
106 		if (w == -1) {
107 			if (errno != EAGAIN)
108 				return got_error_from_errno("write");
109 		} else
110 			wlen += w;
111 	}
112 
113 	return NULL;
114 }