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 "error.h"
  21 #include "file.h"
  22 #include "file_open.h"
  23 #include "internal.h"
  24 #include "log.h"
  25 #include "mem.h"
  26 #include <fcntl.h>
  27 #include <sys/stat.h>
  28 #if HAVE_UNISTD_H
  29 #include <unistd.h>
  30 #endif
  31 #if HAVE_IO_H
  32 #include <io.h>
  33 #endif
  34 #if HAVE_MMAP
  35 #include <sys/mman.h>
  36 #elif HAVE_MAPVIEWOFFILE
  37 #include <windows.h>
  38 #endif
  39
  40 typedef struct FileLogContext {
  41     const AVClass *class;
  42     int   log_offset;
  43     void *log_ctx;
  44 } FileLogContext;
  45
  46 static const AVClass file_log_ctx_class = {
  47     .class_name                = "FILE",
  48     .item_name                 = av_default_item_name,
  49     .option                    = NULL,
  50     .version                   = LIBAVUTIL_VERSION_INT,
  51     .log_level_offset_offset   = offsetof(FileLogContext, log_offset),
  52     .parent_log_context_offset = offsetof(FileLogContext, log_ctx),
  53 };
  54
  55 int av_file_map(const char *filename, uint8_t **bufptr, size_t *size,
  56                 int log_offset, void *log_ctx)
  57 {
  58     FileLogContext file_log_ctx = { &file_log_ctx_class, log_offset, log_ctx };
  59     int err, fd = avpriv_open(filename, O_RDONLY);
  60     struct stat st;
  61     av_unused void *ptr;
  62     off_t off_size;
  63     *bufptr = NULL;
  64     *size = 0;
  65
  66     if (fd < 0) {
  67         err = AVERROR(errno);
  68         av_log(&file_log_ctx, AV_LOG_ERROR, "Cannot read file '%s': %s\n", filename, av_err2str(err));
  69         return err;
  70     }
  71
  72     if (fstat(fd, &st) < 0) {
  73         err = AVERROR(errno);
  74         av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in fstat(): %s\n", av_err2str(err));
  75         close(fd);
  76         return err;
  77     }
  78
  79     off_size = st.st_size;
  80     if (off_size > SIZE_MAX) {
  81         av_log(&file_log_ctx, AV_LOG_ERROR,
  82                "File size for file '%s' is too big\n", filename);
  83         close(fd);
  84         return AVERROR(EINVAL);
  85     }
  86     *size = off_size;
  87
  88     if (!*size) {
  89         *bufptr = NULL;
  90         goto out;
  91     }
  92
  93 #if HAVE_MMAP
  94     ptr = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
  95     if (ptr == MAP_FAILED) {
  96         err = AVERROR(errno);
  97         av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in mmap(): %s\n", av_err2str(err));
  98         close(fd);
  99         *size = 0;
 100         return err;
 101     }
 102     *bufptr = ptr;
 103 #elif HAVE_MAPVIEWOFFILE
 104     {
 105         HANDLE mh, fh = (HANDLE)_get_osfhandle(fd);
 106
 107         mh = CreateFileMapping(fh, NULL, PAGE_READONLY, 0, 0, NULL);
 108         if (!mh) {
 109             av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in CreateFileMapping()\n");
 110             close(fd);
 111             *size = 0;
 112             return -1;
 113         }
 114
 115         ptr = MapViewOfFile(mh, FILE_MAP_COPY, 0, 0, *size);
 116         CloseHandle(mh);
 117         if (!ptr) {
 118             av_log(&file_log_ctx, AV_LOG_ERROR, "Error occurred in MapViewOfFile()\n");
 119             close(fd);
 120             *size = 0;
 121             return -1;
 122         }
 123
 124         *bufptr = ptr;
 125     }
 126 #else
 127     *bufptr = av_malloc(*size);
 128     if (!*bufptr) {
 129         av_log(&file_log_ctx, AV_LOG_ERROR, "Memory allocation error occurred\n");
 130         close(fd);
 131         *size = 0;
 132         return AVERROR(ENOMEM);
 133     }
 134     read(fd, *bufptr, *size);
 135 #endif
 136
 137 out:
 138     close(fd);
 139     return 0;
 140 }
 141
 142 void av_file_unmap(uint8_t *bufptr, size_t size)
 143 {
 144     if (!size || !bufptr)
 145         return;
 146 #if HAVE_MMAP
 147     munmap(bufptr, size);
 148 #elif HAVE_MAPVIEWOFFILE
 149     UnmapViewOfFile(bufptr);
 150 #else
 151     av_free(bufptr);
 152 #endif
 153 }