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;
  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         if (flags & ULOOP_READ)
  40                 sf->fd.cb(&sf->fd, ULOOP_READ);
  41 }
  42
  43 static void ustream_fd_set_read_blocked(struct ustream *s)
  44 {
  45         ustream_fd_set_uloop(s, false);
  46 }
  47
  48 static void ustream_fd_read_pending(struct ustream_fd *sf, bool *more)
  49 {
  50         struct ustream *s = &sf->stream;
  51         int buflen = 0;
  52         ssize_t len;
  53         char *buf;
  54
  55         do {
  56                 buf = ustream_reserve(s, 1, &buflen);
  57                 if (!buf)
  58                         break;
  59
  60                 len = read(sf->fd.fd, buf, buflen);
  61                 if (!len) {
  62                         sf->fd.eof = true;
  63                         return;
  64                 }
  65
  66                 if (len < 0) {
  67                         if (errno == EINTR)
  68                                 continue;
  69
  70                         if (errno == EAGAIN)
  71                                 return;
  72                 }
  73
  74                 ustream_fill_read(s, len);
  75                 *more = true;
  76         } while (1);
  77 }
  78
  79 static int ustream_fd_write(struct ustream *s, const char *buf, int buflen, bool more)
  80 {
  81         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
  82         ssize_t len;
  83
  84         if (!buflen)
  85                 return 0;
  86
  87 retry:
  88         len = write(sf->fd.fd, buf, buflen);
  89         if (!len)
  90                 goto retry;
  91
  92         if (len < 0) {
  93                 if (errno == EINTR)
  94                         goto retry;
  95
  96                 if (errno == EAGAIN || errno == EWOULDBLOCK)
  97                         len = 0;
  98         }
  99
 100         if (len >= 0 && len < buflen)
 101                 ustream_fd_set_uloop(s, true);
 102
 103         return len;
 104 }
 105
 106 static bool __ustream_fd_poll(struct ustream_fd *sf, unsigned int events)
 107 {
 108         struct ustream *s = &sf->stream;
 109         struct uloop_fd *fd = &sf->fd;
 110         bool more = false;
 111
 112         if (events & ULOOP_READ)
 113                 ustream_fd_read_pending(sf, &more);
 114
 115         if (events & ULOOP_WRITE) {
 116                 if (!ustream_write_pending(s))
 117                         ustream_fd_set_uloop(s, false);
 118         }
 119
 120         if (!s->eof && fd->eof) {
 121                 s->eof = true;
 122                 ustream_fd_set_uloop(s, false);
 123                 ustream_state_change(s);
 124         }
 125
 126         return more;
 127 }
 128
 129 static bool ustream_fd_poll(struct ustream *s)
 130 {
 131         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 132
 133         return __ustream_fd_poll(sf, ULOOP_READ | ULOOP_WRITE);
 134 }
 135
 136 static void ustream_uloop_cb(struct uloop_fd *fd, unsigned int events)
 137 {
 138         struct ustream_fd *sf = container_of(fd, struct ustream_fd, fd);
 139
 140         __ustream_fd_poll(sf, events);
 141 }
 142
 143 static void ustream_fd_free(struct ustream *s)
 144 {
 145         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 146
 147         uloop_fd_delete(&sf->fd);
 148 }
 149
 150 void ustream_fd_init(struct ustream_fd *sf, int fd)
 151 {
 152         struct ustream *s = &sf->stream;
 153
 154         ustream_init_defaults(s);
 155
 156         sf->fd.fd = fd;
 157         sf->fd.cb = ustream_uloop_cb;
 158         s->set_read_blocked = ustream_fd_set_read_blocked;
 159         s->write = ustream_fd_write;
 160         s->free = ustream_fd_free;
 161         s->poll = ustream_fd_poll;
 162         ustream_fd_set_uloop(s, false);
 163 }