ustream-fd.c

   1 /*
   2  * ustream - library for stream buffer management
   3  *
   4  * Copyright (C) 2012 Felix Fietkau <nbd@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include <unistd.h>
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include "ustream.h"
  23
  24 static void ustream_fd_set_uloop(struct ustream *s, bool write)
  25 {
  26         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
  27         struct ustream_buf *buf;
  28         unsigned int flags = ULOOP_EDGE_TRIGGER | ULOOP_ERROR_CB;
  29
  30         if (!s->read_blocked && !s->eof)
  31                 flags |= ULOOP_READ;
  32
  33         buf = s->w.head;
  34         if (write || (buf && s->w.data_bytes && !s->write_error))
  35                 flags |= ULOOP_WRITE;
  36
  37         uloop_fd_add(&sf->fd, flags);
  38 }
  39
  40 static void ustream_fd_set_read_blocked(struct ustream *s)
  41 {
  42         ustream_fd_set_uloop(s, false);
  43 }
  44
  45 static void ustream_fd_read_pending(struct ustream_fd *sf, bool *more)
  46 {
  47         struct ustream *s = &sf->stream;
  48         int buflen = 0;
  49         ssize_t len;
  50         char *buf;
  51
  52         do {
  53                 if (s->read_blocked)
  54                         break;
  55
  56                 buf = ustream_reserve(s, 1, &buflen);
  57                 if (!buf)
  58                         break;
  59
  60                 len = read(sf->fd.fd, buf, buflen);
  61                 if (len < 0) {
  62                         if (errno == EINTR)
  63                                 continue;
  64
  65                         if (errno == EAGAIN)
  66                                 return;
  67
  68                         len = 0;
  69                 }
  70
  71                 if (!len) {
  72                         if (!s->eof)
  73                                 ustream_state_change(s);
  74                         s->eof = true;
  75                         ustream_fd_set_uloop(s, false);
  76                         return;
  77                 }
  78
  79                 ustream_fill_read(s, len);
  80                 *more = true;
  81         } while (1);
  82 }
  83
  84 static int ustream_fd_write(struct ustream *s, const char *buf, int buflen, bool more)
  85 {
  86         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
  87         ssize_t ret = 0, len;
  88
  89         if (!buflen)
  90                 return 0;
  91
  92         while (buflen) {
  93                 len = write(sf->fd.fd, buf, buflen);
  94
  95                 if (len < 0) {
  96                         if (errno == EINTR)
  97                                 continue;
  98
  99                         if (errno == EAGAIN || errno == EWOULDBLOCK)
 100                                 break;
 101
 102                         return -1;
 103                 }
 104
 105                 ret += len;
 106                 buf += len;
 107                 buflen -= len;
 108         }
 109
 110         if (buflen)
 111                 ustream_fd_set_uloop(s, true);
 112
 113         return ret;
 114 }
 115
 116 static bool __ustream_fd_poll(struct ustream_fd *sf, unsigned int events)
 117 {
 118         struct ustream *s = &sf->stream;
 119         bool more = false;
 120
 121         if (events & ULOOP_READ)
 122                 ustream_fd_read_pending(sf, &more);
 123
 124         if (events & ULOOP_WRITE) {
 125                 bool no_more = ustream_write_pending(s);
 126                 if (no_more)
 127                         ustream_fd_set_uloop(s, false);
 128         }
 129
 130         if (sf->fd.error && !s->write_error) {
 131                 ustream_state_change(s);
 132                 s->write_error = true;
 133                 ustream_fd_set_uloop(s, false);
 134         }
 135
 136         return more;
 137 }
 138
 139 static bool ustream_fd_poll(struct ustream *s)
 140 {
 141         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 142
 143         return __ustream_fd_poll(sf, ULOOP_READ | ULOOP_WRITE);
 144 }
 145
 146 static void ustream_uloop_cb(struct uloop_fd *fd, unsigned int events)
 147 {
 148         struct ustream_fd *sf = container_of(fd, struct ustream_fd, fd);
 149
 150         __ustream_fd_poll(sf, events);
 151 }
 152
 153 static void ustream_fd_free(struct ustream *s)
 154 {
 155         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 156
 157         uloop_fd_delete(&sf->fd);
 158 }
 159
 160 void ustream_fd_init(struct ustream_fd *sf, int fd)
 161 {
 162         struct ustream *s = &sf->stream;
 163
 164         ustream_init_defaults(s);
 165
 166         sf->fd.fd = fd;
 167         sf->fd.cb = ustream_uloop_cb;
 168         s->set_read_blocked = ustream_fd_set_read_blocked;
 169         s->write = ustream_fd_write;
 170         s->free = ustream_fd_free;
 171         s->poll = ustream_fd_poll;
 172         ustream_fd_set_uloop(s, false);
 173 }