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 bool _init = false;
  25
  26 static void ustream_fd_set_uloop(struct ustream *s, bool write)
  27 {
  28         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
  29         struct ustream_buf *buf;
  30         unsigned int flags = ULOOP_EDGE_TRIGGER;
  31
  32         if (!s->read_blocked && !s->eof)
  33                 flags |= ULOOP_READ;
  34
  35         buf = s->w.head;
  36         if (write || (buf && s->w.data_bytes && !s->write_error))
  37                 flags |= ULOOP_WRITE;
  38
  39         uloop_fd_add(&sf->fd, flags);
  40
  41         if ((flags & ULOOP_READ) && !_init);
  42                 sf->fd.cb(&sf->fd, ULOOP_READ);
  43 }
  44
  45 static void ustream_fd_set_read_blocked(struct ustream *s)
  46 {
  47         ustream_fd_set_uloop(s, false);
  48 }
  49
  50 static void ustream_fd_read_pending(struct ustream_fd *sf, bool *more)
  51 {
  52         struct ustream *s = &sf->stream;
  53         int buflen = 0;
  54         ssize_t len;
  55         char *buf;
  56
  57         do {
  58                 buf = ustream_reserve(s, 1, &buflen);
  59                 if (!buf)
  60                         break;
  61
  62                 len = read(sf->fd.fd, buf, buflen);
  63                 if (len < 0) {
  64                         if (errno == EINTR)
  65                                 continue;
  66
  67                         if (errno == EAGAIN)
  68                                 return;
  69
  70                         len = 0;
  71                 }
  72
  73                 if (!len) {
  74                         sf->fd.eof = true;
  75                         return;
  76                 }
  77
  78                 ustream_fill_read(s, len);
  79                 *more = true;
  80         } while (1);
  81 }
  82
  83 static int ustream_fd_write(struct ustream *s, const char *buf, int buflen, bool more)
  84 {
  85         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
  86         ssize_t len;
  87
  88         if (!buflen)
  89                 return 0;
  90
  91 retry:
  92         len = write(sf->fd.fd, buf, buflen);
  93         if (!len)
  94                 goto retry;
  95
  96         if (len < 0) {
  97                 if (errno == EINTR)
  98                         goto retry;
  99
 100                 if (errno == EAGAIN || errno == EWOULDBLOCK)
 101                         len = 0;
 102         }
 103
 104         if (len >= 0 && len < buflen)
 105                 ustream_fd_set_uloop(s, true);
 106
 107         return len;
 108 }
 109
 110 static bool __ustream_fd_poll(struct ustream_fd *sf, unsigned int events)
 111 {
 112         struct ustream *s = &sf->stream;
 113         struct uloop_fd *fd = &sf->fd;
 114         bool more = false;
 115
 116         if (events & ULOOP_READ)
 117                 ustream_fd_read_pending(sf, &more);
 118
 119         if (events & ULOOP_WRITE) {
 120                 if (!ustream_write_pending(s))
 121                         ustream_fd_set_uloop(s, false);
 122         }
 123
 124         if (!s->eof && fd->eof) {
 125                 s->eof = true;
 126                 ustream_fd_set_uloop(s, false);
 127                 ustream_state_change(s);
 128         }
 129
 130         return more;
 131 }
 132
 133 static bool ustream_fd_poll(struct ustream *s)
 134 {
 135         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 136
 137         return __ustream_fd_poll(sf, ULOOP_READ | ULOOP_WRITE);
 138 }
 139
 140 static void ustream_uloop_cb(struct uloop_fd *fd, unsigned int events)
 141 {
 142         struct ustream_fd *sf = container_of(fd, struct ustream_fd, fd);
 143
 144         __ustream_fd_poll(sf, events);
 145 }
 146
 147 static void ustream_fd_free(struct ustream *s)
 148 {
 149         struct ustream_fd *sf = container_of(s, struct ustream_fd, stream);
 150
 151         uloop_fd_delete(&sf->fd);
 152 }
 153
 154 void ustream_fd_init(struct ustream_fd *sf, int fd)
 155 {
 156         struct ustream *s = &sf->stream;
 157
 158         ustream_init_defaults(s);
 159
 160         sf->fd.fd = fd;
 161         sf->fd.cb = ustream_uloop_cb;
 162         s->set_read_blocked = ustream_fd_set_read_blocked;
 163         s->write = ustream_fd_write;
 164         s->free = ustream_fd_free;
 165         s->poll = ustream_fd_poll;
 166         _init = true;
 167         ustream_fd_set_uloop(s, false);
 168         _init = false;
 169 }