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 <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 }