xref: /third_party/ffmpeg/libavutil/file.c (revision cabdff1a) 
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
38typedef struct FileLogContext {
39    const AVClass *class;
40    int   log_offset;
41    void *log_ctx;
42} FileLogContext;
43
44static 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
53int 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
139out:
140    close(fd);
141    return 0;
142}
143
144void 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
157int av_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx) {
158    return avpriv_tempfile(prefix, filename, log_offset, log_ctx);
159}
160