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