FFmpeg  4.3
file.c
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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;
41  void *log_ctx;
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 }
#define NULL
Definition: coverity.c:32
int size
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
Memory handling functions.
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:235
int avpriv_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx)
Wrapper to work around the lack of mkstemp() on mingw.
Definition: file_open.c:110
const char * class_name
The name of the class; usually it is the same name as the context structure type to which the AVClass...
Definition: log.h:72
uint8_t
#define av_malloc(s)
int avpriv_open(const char *filename, int flags,...)
A wrapper for open() setting O_CLOEXEC.
Definition: file_open.c:66
Misc file utilities.
#define av_log(a,...)
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition: log.h:176
void av_file_unmap(uint8_t *bufptr, size_t size)
Unmap or free the buffer bufptr created by av_file_map().
Definition: file.c:144
int av_file_map(const char *filename, uint8_t **bufptr, size_t *size, int log_offset, void *log_ctx)
Read the file with name filename, and put its content in a newly allocated buffer or map it with mmap...
Definition: file.c:53
#define AVERROR(e)
Definition: error.h:43
common internal API header
int log_offset
Definition: file.c:40
int av_tempfile(const char *prefix, char **filename, int log_offset, void *log_ctx)
Wrapper to work around the lack of mkstemp() on mingw.
Definition: file.c:157
Describe the class of an AVClass context structure.
Definition: log.h:67
void * log_ctx
Definition: file.c:41
int av_strerror(int errnum, char *errbuf, size_t errbuf_size)
Put a description of the AVERROR code errnum in errbuf.
Definition: error.c:105
static const AVClass file_log_ctx_class
Definition: file.c:44
#define av_free(p)
FILE * out
Definition: movenc.c:54
#define av_unused
Definition: attributes.h:131
#define mh