libavutil/file.c

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #include "config.h"
  20 #include "file.h"
  21 #include "internal.h"
  22 #include "log.h"
  23 #include "mem.h"
  24 #include <fcntl.h>
  25 #include <sys/stat.h>
  26 #if HAVE_UNISTD_H
  27 #include <unistd.h>
  28 #endif
  29 #if HAVE_IO_H
  30 #include <io.h>
  31 #endif
  32 #if HAVE_MMAP
  33 #include <sys/mman.h>
  34 #elif HAVE_MAPVIEWOFFILE
  35 #include <windows.h>
  36 #endif
  37
  38 typedef struct FileLogContext {
  39     const AVClass *class;
  40     int   log_offset;
  41     void *log_ctx;
  42 } FileLogContext;
  43
  44 static const AVClass file_log_ctx_class = {
  45     .class_name                = "FILE",
  46     .item_name                 = av_default_item_name,
  47     .option                    = NULL,
  48     .version                   = LIBAVUTIL_VERSION_INT,
  49     .log_level_offset_offset   = offsetof(FileLogContext, log_offset),
  50     .parent_log_context_offset = offsetof(FileLogContext, log_ctx),
  51 };
  52
  53 int av_file_map(const char *filename, uint8_t **bufptr, size_t *size,
  54                 int log_offset, void *log_ctx)
  55 {
  56     FileLogContext file_log_ctx = { &file_log_ctx_class, log_offset, log_ctx };
  57     int err, fd = avpriv_open(filename, O_RDONLY);
  58     struct stat st;
  59     av_unused void *ptr;
  60     off_t off_size;
  61     char errbuf[128];
  62     *bufptr = NULL;
  63     *size = 0;
  64
  65     if (fd < 0) {
  66         err = AVERROR(errno);
  67         av_strerror(err, errbuf, sizeof(errbuf));
  68         av_log(&file_log_ctx, AV_LOG_ERROR, "Cannot read file '%s': %s\n", filename, errbuf);
  69         return err;
  70     }
  71
  72     if (fstat(fd, &st) < 0) {
  73         err = AVERROR(errno);
  74         av_strerror(err, errbuf, sizeof(errbuf));
  75         av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in fstat(): %s\n", errbuf);
  76         close(fd);
  77         return err;
  78     }
  79
  80     off_size = st.st_size;
  81     if (off_size > SIZE_MAX) {
  82         av_log(&file_log_ctx, AV_LOG_ERROR,
  83                "File size for file '%s' is too big\n", filename);
  84         close(fd);
  85         return AVERROR(EINVAL);
  86     }
  87     *size = off_size;
  88
  89     if (!*size) {
  90         *bufptr = NULL;
  91         goto out;
  92     }
  93
  94 #if HAVE_MMAP
  95     ptr = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
  96     if (ptr == MAP_FAILED) {
  97         err = AVERROR(errno);
  98         av_strerror(err, errbuf, sizeof(errbuf));
  99         av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in mmap(): %s\n", errbuf);
 100         close(fd);
 101         *size = 0;
 102         return err;
 103     }
 104     *bufptr = ptr;
 105 #elif HAVE_MAPVIEWOFFILE
 106     {
 107         HANDLE mh, fh = (HANDLE)_get_osfhandle(fd);
 108
 109         mh = CreateFileMapping(fh, NULL, PAGE_READONLY, 0, 0, NULL);
 110         if (!mh) {
 111             av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in CreateFileMapping()\n");
 112             close(fd);
 113             *size = 0;
 114             return -1;
 115         }
 116
 117         ptr = MapViewOfFile(mh, FILE_MAP_READ, 0, 0, *size);
 118         CloseHandle(mh);
 119         if (!ptr) {
 120             av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in MapViewOfFile()\n");
 121             close(fd);
 122             *size = 0;
 123             return -1;
 124         }
 125
 126         *bufptr = ptr;
 127     }
 128 #else
 129     *bufptr = av_malloc(*size);
 130     if (!*bufptr) {
 131         av_log(&file_log_ctx, AV_LOG_ERROR, "Memory allocation error occurred\n");
 132         close(fd);
 133         *size = 0;
 134         return AVERROR(ENOMEM);
 135     }
 136     read(fd, *bufptr, *size);
 137 #endif
 138
 139 out:
 140     close(fd);
 141     return 0;
 142 }
 143
 144 void av_file_unmap(uint8_t *bufptr, size_t size)
 145 {
 146     if (!size || !bufptr)
 147         return;
 148 #if HAVE_MMAP
 149     munmap(bufptr, size);
 150 #elif HAVE_MAPVIEWOFFILE
 151     UnmapViewOfFile(bufptr);
 152 #else
 153     av_free(bufptr);
 154 #endif
 155 }
 156
 157 int av_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx) {
 158     return avpriv_tempfile(prefix, filename, log_offset, log_ctx);
 159 }