1 /*****************************************************************************
2 * mmap.c: memory-mapped file input
3 *****************************************************************************
4 * Copyright © 2007-2008 Rémi Denis-Courmont
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
20 *****************************************************************************/
26 #include <vlc_common.h>
27 #include <vlc_plugin.h>
28 #include <vlc_access.h>
29 #include <vlc_input.h>
30 #include <vlc_charset.h>
31 #include <vlc_interface.h>
36 #include <sys/types.h>
42 #define FILE_MMAP_TEXT N_("Use file memory mapping")
43 #define FILE_MMAP_LONGTEXT N_( \
44 "Try to use memory mapping to read files and block devices." )
47 /*# define MMAP_DEBUG 1*/
50 static int Open (vlc_object_t *);
51 static void Close (vlc_object_t *);
54 set_shortname (N_("MMap"));
55 set_description (N_("Memory-mapped file input"));
56 set_category (CAT_INPUT);
57 set_subcategory (SUBCAT_INPUT_ACCESS);
58 set_capability ("access", 52);
59 add_shortcut ("file");
60 set_callbacks (Open, Close);
62 add_bool ("file-mmap", false, NULL,
64 add_bool ("file-mmap", true, NULL,
66 FILE_MMAP_TEXT, FILE_MMAP_LONGTEXT, true);
69 static block_t *Block (access_t *);
70 static int Seek (access_t *, int64_t);
71 static int Control (access_t *, int, va_list);
80 #define MMAP_SIZE (1 << 20)
82 static int Open (vlc_object_t *p_this)
84 access_t *p_access = (access_t *)p_this;
86 const char *path = p_access->psz_path;
89 if (!var_CreateGetBool (p_this, "file-mmap"))
90 return VLC_EGENERIC; /* disabled */
92 STANDARD_BLOCK_ACCESS_INIT;
94 if (!strcmp (p_access->psz_path, "-"))
98 msg_Dbg (p_access, "opening file %s", path);
99 fd = utf8_open (path, O_RDONLY | O_NOCTTY, 0666);
104 msg_Warn (p_access, "cannot open %s: %m", path);
107 fcntl (fd, F_SETFD, fcntl (fd, F_GETFD) | FD_CLOEXEC);
109 /* mmap() is only safe for regular and block special files.
110 * For other types, it may be some idiosyncrasic interface (e.g. packet
111 * sockets are a good example), if it works at all. */
116 msg_Err (p_access, "cannot stat %s: %m", path);
120 if (!S_ISREG (st.st_mode) && !S_ISBLK (st.st_mode))
122 msg_Dbg (p_access, "skipping non regular file %s", path);
126 #if defined(HAVE_FCNTL_H)
127 /* We'd rather use any available memory for reading ahead
128 * than for caching what we've already mmap'ed */
129 # if defined(F_RDAHEAD)
130 fcntl (fd, F_RDAHEAD, 1);
132 # if defined(F_NOCACHE)
133 fcntl (fd, F_NOCACHE, 1);
137 /* Autodetect mmap() support */
140 void *addr = mmap (NULL, 1, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
141 if (addr != MAP_FAILED)
147 p_sys->page_size = sysconf (_SC_PAGE_SIZE);
148 p_sys->mtu = MMAP_SIZE;
149 if (p_sys->mtu < p_sys->page_size)
150 p_sys->mtu = p_sys->page_size;
153 p_access->info.i_size = st.st_size;
154 #ifdef HAVE_POSIX_FADVISE
155 posix_fadvise (fd, 0, 0, POSIX_FADV_SEQUENTIAL);
168 static void Close (vlc_object_t * p_this)
170 access_t *p_access = (access_t *)p_this;
171 access_sys_t *p_sys = p_access->p_sys;
173 close (p_sys->fd); /* don't care about error when only reading */
177 static block_t *Block (access_t *p_access)
179 access_sys_t *p_sys = p_access->p_sys;
181 /* Check if file size changed... */
184 if ((fstat (p_sys->fd, &st) == 0)
185 && (st.st_size != p_access->info.i_size))
187 p_access->info.i_size = st.st_size;
188 p_access->info.i_update |= INPUT_UPDATE_SIZE;
191 if ((uint64_t)p_access->info.i_pos >= (uint64_t)p_access->info.i_size)
193 /* We are at end of file */
194 p_access->info.b_eof = true;
195 msg_Dbg (p_access, "at end of memory mapped file");
200 int64_t dbgpos = lseek (p_sys->fd, 0, SEEK_CUR);
201 if (dbgpos != p_access->info.i_pos)
202 msg_Err (p_access, "position: 0x%08llx instead of 0x%08llx",
203 p_access->info.i_pos, dbgpos);
206 const uintptr_t page_mask = p_sys->page_size - 1;
207 /* Start the mapping on a page boundary: */
208 off_t outer_offset = p_access->info.i_pos & ~page_mask;
209 /* Skip useless bytes at the beginning of the first page: */
210 size_t inner_offset = p_access->info.i_pos & page_mask;
211 /* Map no more bytes than remain: */
212 size_t length = p_sys->mtu;
213 if (outer_offset + length > p_access->info.i_size)
214 length = p_access->info.i_size - outer_offset;
216 assert (outer_offset <= p_access->info.i_pos); /* and */
217 assert (p_access->info.i_pos < p_access->info.i_size); /* imply */
218 assert (outer_offset < p_access->info.i_size); /* imply */
221 /* NOTE: We use PROT_WRITE and MAP_PRIVATE so that the block can be
222 * modified down the chain, without messing up with the underlying
223 * original file. This does NOT need open write permission. */
224 void *addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE
228 , p_sys->fd, outer_offset);
229 if (addr == MAP_FAILED)
231 msg_Err (p_access, "memory mapping failed (%m)");
232 intf_UserFatal (p_access, false, _("File reading failed"),
233 _("VLC could not read the file."));
236 #ifdef HAVE_POSIX_MADVISE
237 posix_madvise (addr, length, POSIX_MADV_SEQUENTIAL);
240 block_t *block = block_mmap_Alloc (addr, length);
244 block->p_buffer += inner_offset;
245 block->i_buffer -= inner_offset;
248 msg_Dbg (p_access, "mapped 0x%lx bytes at %p from offset 0x%lx",
249 (unsigned long)length, addr, (unsigned long)outer_offset);
251 /* Compare normal I/O with memory mapping */
252 char *buf = malloc (block->i_buffer);
253 ssize_t i_read = read (p_sys->fd, buf, block->i_buffer);
255 if (i_read != (ssize_t)block->i_buffer)
256 msg_Err (p_access, "read %u instead of %u bytes", (unsigned)i_read,
257 (unsigned)block->i_buffer);
258 if (memcmp (buf, block->p_buffer, block->i_buffer))
259 msg_Err (p_access, "inconsistent data buffer");
263 p_access->info.i_pos = outer_offset + length;
267 p_access->info.b_eof = true;
272 static int Seek (access_t *p_access, int64_t i_pos)
275 lseek (p_access->p_sys->fd, i_pos, SEEK_SET);
278 p_access->info.i_pos = i_pos;
279 p_access->info.b_eof = false;
284 static int Control (access_t *p_access, int query, va_list args)
286 access_sys_t *p_sys = p_access->p_sys;
290 case ACCESS_CAN_SEEK:
291 case ACCESS_CAN_FASTSEEK:
292 case ACCESS_CAN_PAUSE:
293 case ACCESS_CAN_CONTROL_PACE:
294 *((bool *)va_arg (args, bool *)) = true;
298 *((int *)va_arg (args, int *)) = p_sys->mtu;
301 case ACCESS_GET_PTS_DELAY:
303 int delay_ms = var_CreateGetInteger (p_access, "file-caching");
304 *((int64_t *)va_arg (args, int64_t *)) = delay_ms * INT64_C (1000);
308 case ACCESS_GET_TITLE_INFO:
309 case ACCESS_GET_META:
312 case ACCESS_SET_PAUSE_STATE:
315 case ACCESS_SET_TITLE:
316 case ACCESS_SET_SEEKPOINT:
317 case ACCESS_SET_PRIVATE_ID_STATE:
318 case ACCESS_SET_PRIVATE_ID_CA:
319 case ACCESS_GET_PRIVATE_ID_STATE:
320 case ACCESS_GET_CONTENT_TYPE:
324 msg_Warn (p_access, "unimplemented query %d in control", query);