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 struct ustream_free_guard guard; 49 int buflen = 0; 50 ssize_t len; 51 char *buf; 52 53 do { 54 if (s->read_blocked) 55 break; 56 57 buf = ustream_reserve(s, 1, &buflen); 58 if (!buf) 59 break; 60 61 len = read(sf->fd.fd, buf, buflen); 62 if (len < 0) { 63 if (errno == EINTR) 64 continue; 65 66 if (errno == EAGAIN || errno == ENOTCONN) 67 return; 68 69 len = 0; 70 } 71 72 if (!len) { 73 if (!s->eof) 74 ustream_state_change(s); 75 s->eof = true; 76 ustream_fd_set_uloop(s, false); 77 return; 78 } 79 80 ustream_free_guard_set(s, &guard); 81 ustream_fill_read(s, len); 82 if (ustream_free_guard_check(s, &guard)) 83 return; 84 85 *more = true; 86 } while (1); 87 } 88 89 static int ustream_fd_write(struct ustream *s, const char *buf, int buflen, bool more) 90 { 91 struct ustream_fd *sf = container_of(s, struct ustream_fd, stream); 92 ssize_t ret = 0, len; 93 94 if (!buflen) 95 return 0; 96 97 while (buflen) { 98 len = write(sf->fd.fd, buf, buflen); 99 100 if (len < 0) { 101 if (errno == EINTR) 102 continue; 103 104 if (errno == EAGAIN || errno == EWOULDBLOCK || errno == ENOTCONN) 105 break; 106 107 return -1; 108 } 109 110 ret += len; 111 buf += len; 112 buflen -= len; 113 } 114 115 if (buflen) 116 ustream_fd_set_uloop(s, true); 117 118 return ret; 119 } 120 121 static bool __ustream_fd_poll(struct ustream_fd *sf, unsigned int events) 122 { 123 struct ustream *s = &sf->stream; 124 struct ustream_free_guard guard; 125 bool more = false; 126 127 if (events & ULOOP_READ) { 128 ustream_free_guard_set(s, &guard); 129 ustream_fd_read_pending(sf, &more); 130 if (ustream_free_guard_check(s, &guard)) 131 return more; 132 } 133 134 if (events & ULOOP_WRITE) { 135 bool no_more; 136 137 ustream_free_guard_set(s, &guard); 138 no_more = ustream_write_pending(s); 139 if (ustream_free_guard_check(s, &guard)) 140 return more; 141 142 if (no_more) 143 ustream_fd_set_uloop(s, false); 144 } 145 146 if (sf->fd.error && !s->write_error) { 147 ustream_state_change(s); 148 s->write_error = true; 149 ustream_fd_set_uloop(s, false); 150 } 151 152 return more; 153 } 154 155 static bool ustream_fd_poll(struct ustream *s) 156 { 157 struct ustream_fd *sf = container_of(s, struct ustream_fd, stream); 158 159 return __ustream_fd_poll(sf, ULOOP_READ | ULOOP_WRITE); 160 } 161 162 static void ustream_uloop_cb(struct uloop_fd *fd, unsigned int events) 163 { 164 struct ustream_fd *sf = container_of(fd, struct ustream_fd, fd); 165 166 __ustream_fd_poll(sf, events); 167 } 168 169 static void ustream_fd_free(struct ustream *s) 170 { 171 struct ustream_fd *sf = container_of(s, struct ustream_fd, stream); 172 173 uloop_fd_delete(&sf->fd); 174 } 175 176 void ustream_fd_init(struct ustream_fd *sf, int fd) 177 { 178 struct ustream *s = &sf->stream; 179 180 ustream_init_defaults(s); 181 182 sf->fd.fd = fd; 183 sf->fd.cb = ustream_uloop_cb; 184 s->set_read_blocked = ustream_fd_set_read_blocked; 185 s->write = ustream_fd_write; 186 s->free = ustream_fd_free; 187 s->poll = ustream_fd_poll; 188 ustream_fd_set_uloop(s, false); 189 } 190
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