ffmpeg/libavformat/file.c

   1 /*
   2  * buffered file I/O
   3  * Copyright (c) 2001 Fabrice Bellard
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "libavutil/avstring.h"
  23 #include "libavutil/internal.h"
  24 #include "libavutil/opt.h"
  25 #include "avformat.h"
  26 #include <fcntl.h>
  27 #if HAVE_IO_H
  28 #include <io.h>
  29 #endif
  30 #if HAVE_UNISTD_H
  31 #include <unistd.h>
  32 #endif
  33 #include <sys/stat.h>
  34 #include <stdlib.h>
  35 #include "os_support.h"
  36 #include "url.h"
  37
  38 /* Some systems may not have S_ISFIFO */
  39 #ifndef S_ISFIFO
  40 #  ifdef S_IFIFO
  41 #    define S_ISFIFO(m) (((m) & S_IFMT) == S_IFIFO)
  42 #  else
  43 #    define S_ISFIFO(m) 0
  44 #  endif
  45 #endif
  46
  47 /* standard file protocol */
  48
  49 typedef struct FileContext {
  50     const AVClass *class;
  51     int fd;
  52     int trunc;
  53     int blocksize;
  54 } FileContext;
  55
  56 static const AVOption file_options[] = {
  57     { "truncate", "truncate existing files on write", offsetof(FileContext, trunc), AV_OPT_TYPE_INT, { .i64 = 1 }, 0, 1, AV_OPT_FLAG_ENCODING_PARAM },
  58     { "blocksize", "set I/O operation maximum block size", offsetof(FileContext, blocksize), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
  59     { NULL }
  60 };
  61
  62 static const AVOption pipe_options[] = {
  63     { "blocksize", "set I/O operation maximum block size", offsetof(FileContext, blocksize), AV_OPT_TYPE_INT, { .i64 = INT_MAX }, 1, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
  64     { NULL }
  65 };
  66
  67 static const AVClass file_class = {
  68     .class_name = "file",
  69     .item_name  = av_default_item_name,
  70     .option     = file_options,
  71     .version    = LIBAVUTIL_VERSION_INT,
  72 };
  73
  74 static const AVClass pipe_class = {
  75     .class_name = "pipe",
  76     .item_name  = av_default_item_name,
  77     .option     = pipe_options,
  78     .version    = LIBAVUTIL_VERSION_INT,
  79 };
  80
  81 static int file_read(URLContext *h, unsigned char *buf, int size)
  82 {
  83     FileContext *c = h->priv_data;
  84     int r;
  85     size = FFMIN(size, c->blocksize);
  86     r = read(c->fd, buf, size);
  87     return (-1 == r)?AVERROR(errno):r;
  88 }
  89
  90 static int file_write(URLContext *h, const unsigned char *buf, int size)
  91 {
  92     FileContext *c = h->priv_data;
  93     int r;
  94     size = FFMIN(size, c->blocksize);
  95     r = write(c->fd, buf, size);
  96     return (-1 == r)?AVERROR(errno):r;
  97 }
  98
  99 static int file_get_handle(URLContext *h)
 100 {
 101     FileContext *c = h->priv_data;
 102     return c->fd;
 103 }
 104
 105 static int file_check(URLContext *h, int mask)
 106 {
 107     int ret = 0;
 108     const char *filename = h->filename;
 109     av_strstart(filename, "file:", &filename);
 110
 111     {
 112 #if HAVE_ACCESS && defined(R_OK)
 113     if (access(filename, F_OK) < 0)
 114         return AVERROR(errno);
 115     if (mask&AVIO_FLAG_READ)
 116         if (access(filename, R_OK) >= 0)
 117             ret |= AVIO_FLAG_READ;
 118     if (mask&AVIO_FLAG_WRITE)
 119         if (access(filename, W_OK) >= 0)
 120             ret |= AVIO_FLAG_WRITE;
 121 #else
 122     struct stat st;
 123     ret = stat(filename, &st);
 124     if (ret < 0)
 125         return AVERROR(errno);
 126
 127     ret |= st.st_mode&S_IRUSR ? mask&AVIO_FLAG_READ  : 0;
 128     ret |= st.st_mode&S_IWUSR ? mask&AVIO_FLAG_WRITE : 0;
 129 #endif
 130     }
 131     return ret;
 132 }
 133
 134 #if CONFIG_FILE_PROTOCOL
 135
 136 static int file_open(URLContext *h, const char *filename, int flags)
 137 {
 138     FileContext *c = h->priv_data;
 139     int access;
 140     int fd;
 141     struct stat st;
 142
 143     av_strstart(filename, "file:", &filename);
 144
 145     if (flags & AVIO_FLAG_WRITE && flags & AVIO_FLAG_READ) {
 146         access = O_CREAT | O_RDWR;
 147         if (c->trunc)
 148             access |= O_TRUNC;
 149     } else if (flags & AVIO_FLAG_WRITE) {
 150         access = O_CREAT | O_WRONLY;
 151         if (c->trunc)
 152             access |= O_TRUNC;
 153     } else {
 154         access = O_RDONLY;
 155     }
 156 #ifdef O_BINARY
 157     access |= O_BINARY;
 158 #endif
 159     fd = avpriv_open(filename, access, 0666);
 160     if (fd == -1)
 161         return AVERROR(errno);
 162     c->fd = fd;
 163
 164     h->is_streamed = !fstat(fd, &st) && S_ISFIFO(st.st_mode);
 165
 166     return 0;
 167 }
 168
 169 /* XXX: use llseek */
 170 static int64_t file_seek(URLContext *h, int64_t pos, int whence)
 171 {
 172     FileContext *c = h->priv_data;
 173     int64_t ret;
 174
 175     if (whence == AVSEEK_SIZE) {
 176         struct stat st;
 177         ret = fstat(c->fd, &st);
 178         return ret < 0 ? AVERROR(errno) : (S_ISFIFO(st.st_mode) ? 0 : st.st_size);
 179     }
 180
 181     ret = lseek(c->fd, pos, whence);
 182
 183     return ret < 0 ? AVERROR(errno) : ret;
 184 }
 185
 186 static int file_close(URLContext *h)
 187 {
 188     FileContext *c = h->priv_data;
 189     return close(c->fd);
 190 }
 191
 192 URLProtocol ff_file_protocol = {
 193     .name                = "file",
 194     .url_open            = file_open,
 195     .url_read            = file_read,
 196     .url_write           = file_write,
 197     .url_seek            = file_seek,
 198     .url_close           = file_close,
 199     .url_get_file_handle = file_get_handle,
 200     .url_check           = file_check,
 201     .priv_data_size      = sizeof(FileContext),
 202     .priv_data_class     = &file_class,
 203 };
 204
 205 #endif /* CONFIG_FILE_PROTOCOL */
 206
 207 #if CONFIG_PIPE_PROTOCOL
 208
 209 static int pipe_open(URLContext *h, const char *filename, int flags)
 210 {
 211     FileContext *c = h->priv_data;
 212     int fd;
 213     char *final;
 214     av_strstart(filename, "pipe:", &filename);
 215
 216     fd = strtol(filename, &final, 10);
 217     if((filename == final) || *final ) {/* No digits found, or something like 10ab */
 218         if (flags & AVIO_FLAG_WRITE) {
 219             fd = 1;
 220         } else {
 221             fd = 0;
 222         }
 223     }
 224 #if HAVE_SETMODE
 225     setmode(fd, O_BINARY);
 226 #endif
 227     c->fd = fd;
 228     h->is_streamed = 1;
 229     return 0;
 230 }
 231
 232 URLProtocol ff_pipe_protocol = {
 233     .name                = "pipe",
 234     .url_open            = pipe_open,
 235     .url_read            = file_read,
 236     .url_write           = file_write,
 237     .url_get_file_handle = file_get_handle,
 238     .url_check           = file_check,
 239     .priv_data_size      = sizeof(FileContext),
 240     .priv_data_class     = &pipe_class,
 241 };
 242
 243 #endif /* CONFIG_PIPE_PROTOCOL */