lib/pollfd.c

   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 "got_compat.h"
  18
  19 #include <errno.h>
  20 #include <stdio.h>
  21 #include <signal.h>
  22 #include <poll.h>
  23 #include <time.h>
  24 #include <unistd.h>
  25
  26 #include "got_error.h"
  27
  28 #include "got_lib_poll.h"
  29
  30 const struct got_error *
  31 got_poll_fd(int fd, int events, int timeout)
  32 {
  33         struct pollfd pfd[1];
  34         struct timespec ts;
  35         sigset_t sigset;
  36         int n;
  37
  38         pfd[0].fd = fd;
  39         pfd[0].events = events;
  40
  41         ts.tv_sec = timeout;
  42         ts.tv_nsec = 0;
  43
  44         if (sigemptyset(&sigset) == -1)
  45                 return got_error_from_errno("sigemptyset");
  46         if (sigaddset(&sigset, SIGWINCH) == -1)
  47                 return got_error_from_errno("sigaddset");
  48
  49         n = ppoll(pfd, 1, timeout == INFTIM ? NULL : &ts, &sigset);
  50         if (n == -1)
  51                 return got_error_from_errno("ppoll");
  52         if (n == 0) {
  53                 if (pfd[0].revents & POLLHUP)
  54                         return got_error(GOT_ERR_EOF);
  55                 return got_error(GOT_ERR_TIMEOUT);
  56         }
  57         if (pfd[0].revents & (POLLERR | POLLNVAL))
  58                 return got_error_from_errno("poll error");
  59         if (pfd[0].revents & events)
  60                 return NULL;
  61         if (pfd[0].revents & POLLHUP)
  62                 return got_error(GOT_ERR_EOF);
  63
  64         return got_error(GOT_ERR_INTERRUPT);
  65 }
  66
  67 const struct got_error *
  68 got_poll_read_full_timeout(int fd, size_t *len, void *buf, size_t bufsize,
  69     size_t minbytes, int timeout)
  70 {
  71         const struct got_error *err = NULL;
  72         size_t have = 0;
  73         ssize_t r;
  74
  75         if (minbytes > bufsize)
  76                 return got_error(GOT_ERR_NO_SPACE);
  77
  78         while (have < minbytes) {
  79                 err = got_poll_fd(fd, POLLIN, timeout);
  80                 if (err)
  81                         return err;
  82                 r = read(fd, buf + have, bufsize - have);
  83                 if (r == -1)
  84                         return got_error_from_errno("read");
  85                 if (r == 0)
  86                         return got_error(GOT_ERR_EOF);
  87                 have += r;
  88         }
  89
  90         *len = have;
  91         return NULL;
  92 }
  93
  94 const struct got_error *
  95 got_poll_read_full(int fd, size_t *len, void *buf, size_t bufsize,
  96     size_t minbytes)
  97 {
  98         return got_poll_read_full_timeout(fd, len, buf, bufsize,
  99             minbytes, INFTIM);
 100 }
 101
 102 const struct got_error *
 103 got_poll_write_full(int fd, const void *buf, off_t len)
 104 {
 105         const struct got_error *err = NULL;
 106         off_t wlen = 0;
 107         ssize_t w = 0;
 108
 109         while (wlen != len) {
 110                 if (wlen > 0) {
 111                         err = got_poll_fd(fd, POLLOUT, INFTIM);
 112                         if (err)
 113                                 return err;
 114                 }
 115                 w = write(fd, buf + wlen, len - wlen);
 116                 if (w == -1) {
 117                         if (errno != EAGAIN)
 118                                 return got_error_from_errno("write");
 119                 } else
 120                         wlen += w;
 121         }
 122
 123         return NULL;
 124 }