FFmpeg
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
#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:191
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.
ptrdiff_t size
Definition: opengl_enc.c:100
#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
common internal API header
PVOID HANDLE
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
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Frame references ownership and permissions
#define av_unused
Definition: attributes.h:125
#define mh