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 *****************************************************************************/
27 #include <vlc_access.h>
28 #include <vlc_input.h>
29 #include <vlc_charset.h>
30 #include <vlc_interface.h>
35 #include <sys/types.h>
41 #define FILE_MMAP_TEXT N_("Use file memory mapping")
42 #define FILE_MMAP_LONGTEXT N_( \
43 "Try to use memory mapping to read files and block devices." )
45 static int Open (vlc_object_t *);
46 static void Close (vlc_object_t *);
49 set_shortname (_("MMap"));
50 set_description (_("Memory-mapped file input"));
51 set_category (CAT_INPUT);
52 set_subcategory (SUBCAT_INPUT_ACCESS);
53 set_capability ("access2", 52);
54 add_shortcut ("file");
55 set_callbacks (Open, Close);
57 add_bool ("file-mmap", VLC_TRUE, NULL,
58 FILE_MMAP_TEXT, FILE_MMAP_LONGTEXT, VLC_TRUE);
61 static block_t *Block (access_t *);
62 static int Seek (access_t *, int64_t);
63 static int Control (access_t *, int, va_list);
72 #define MMAP_SIZE (1 << 20)
74 static int Open (vlc_object_t *p_this)
76 access_t *p_access = (access_t *)p_this;
78 const char *path = p_access->psz_path;
81 if (!var_CreateGetBool (p_this, "file-mmap"))
82 return VLC_EGENERIC; /* disabled */
84 STANDARD_BLOCK_ACCESS_INIT;
86 if (!strcmp (p_access->psz_path, "-"))
90 msg_Dbg (p_access, "opening file %s", path);
91 fd = utf8_open (path, O_RDONLY | O_NOCTTY, 0666);
96 msg_Warn (p_access, "cannot open %s: %m", path);
100 /* mmap() is only safe for regular and block special files.
101 * For other types, it may be some idiosyncrasic interface (e.g. packet
102 * sockets are a good example), if it works at all. */
107 msg_Err (p_access, "cannot stat %s: %m", path);
111 if (!S_ISREG (st.st_mode) && !S_ISBLK (st.st_mode))
113 msg_Dbg (p_access, "skipping non regular file %s", path);
117 /* Autodetect mmap() support */
120 void *addr = mmap (NULL, 1, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
121 if (addr != MAP_FAILED)
127 p_sys->page_size = sysconf (_SC_PAGE_SIZE);
128 p_sys->mtu = MMAP_SIZE;
129 if (p_sys->mtu < p_sys->page_size)
130 p_sys->mtu = p_sys->page_size;
133 p_access->info.i_size = st.st_size;
134 #ifdef HAVE_POSIX_FADVISE
135 posix_fadvise (fd, 0, 0, POSIX_FADV_SEQUENTIAL);
148 static void Close (vlc_object_t * p_this)
150 access_t *p_access = (access_t *)p_this;
151 access_sys_t *p_sys = p_access->p_sys;
153 close (p_sys->fd); /* don't care about error when only reading */
157 static block_t *Block (access_t *p_access)
159 access_sys_t *p_sys = p_access->p_sys;
161 if ((uint64_t)p_access->info.i_pos >= (uint64_t)p_access->info.i_size)
163 /* End of file - check if file size changed... */
166 if ((fstat (p_sys->fd, &st) == 0)
167 && (st.st_size != p_access->info.i_size))
169 p_access->info.i_size = st.st_size;
170 p_access->info.i_update |= INPUT_UPDATE_SIZE;
173 /* Really at end of file then */
174 if ((uint64_t)p_access->info.i_pos >= (uint64_t)p_access->info.i_size)
176 p_access->info.b_eof = VLC_TRUE;
177 msg_Dbg (p_access, "at end of memory mapped file");
183 int64_t dbgpos = lseek (p_sys->fd, 0, SEEK_CUR);
184 if (dbgpos != p_access->info.i_pos)
185 msg_Err (p_access, "position: 0x%08llx instead of 0x%08llx",
186 p_access->info.i_pos, dbgpos);
189 const uintptr_t page_mask = p_sys->page_size - 1;
190 /* Start the mapping on a page boundary: */
191 off_t outer_offset = p_access->info.i_pos & ~page_mask;
192 /* Skip useless bytes at the beginning of the first page: */
193 size_t inner_offset = p_access->info.i_pos & page_mask;
194 /* Map no more bytes than remain: */
195 size_t length = p_sys->mtu;
196 if (outer_offset + length > p_access->info.i_size)
197 length = p_access->info.i_size - outer_offset;
199 assert (outer_offset <= p_access->info.i_pos); /* and */
200 assert (p_access->info.i_pos < p_access->info.i_size); /* imply */
201 assert (outer_offset < p_access->info.i_size); /* imply */
204 /* NOTE: We use PROT_WRITE and MAP_PRIVATE so that the block can be
205 * modified down the chain, without messing up with the underlying
206 * original file. This does NOT need open write permission. */
207 void *addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE,
208 p_sys->fd, outer_offset);
209 if (addr == MAP_FAILED)
211 msg_Err (p_access, "memory mapping failed (%m)");
212 intf_UserFatal (p_access, VLC_FALSE, _("File reading failed"),
213 _("VLC could not read the file."));
214 msleep (INPUT_ERROR_SLEEP);
217 #ifdef HAVE_POSIX_MADVISE
218 posix_madvise (addr, length, POSIX_MADV_SEQUENTIAL);
221 block_t *block = block_mmap_Alloc (addr, length);
225 block->p_buffer += inner_offset;
226 block->i_buffer -= inner_offset;
229 msg_Dbg (p_access, "mapped 0x%lx bytes at %p from offset 0x%lx",
230 (unsigned long)length, addr, (unsigned long)outer_offset);
232 /* Compare normal I/O with memory mapping */
233 char *buf = malloc (block->i_buffer);
234 ssize_t i_read = read (p_sys->fd, buf, block->i_buffer);
236 if (i_read != (ssize_t)block->i_buffer)
237 msg_Err (p_access, "read %u instead of %u bytes", (unsigned)i_read,
238 (unsigned)block->i_buffer);
239 if (memcmp (buf, block->p_buffer, block->i_buffer))
240 msg_Err (p_access, "inconsistent data buffer");
244 p_access->info.i_pos = outer_offset + length;
249 static int Seek (access_t *p_access, int64_t i_pos)
252 lseek (p_access->p_sys->fd, i_pos, SEEK_SET);
255 p_access->info.i_pos = i_pos;
256 p_access->info.b_eof = VLC_FALSE;
261 static int Control (access_t *p_access, int query, va_list args)
263 access_sys_t *p_sys = p_access->p_sys;
267 case ACCESS_CAN_SEEK:
268 case ACCESS_CAN_FASTSEEK:
269 case ACCESS_CAN_PAUSE:
270 case ACCESS_CAN_CONTROL_PACE:
271 *((vlc_bool_t *)va_arg (args, vlc_bool_t *)) = VLC_TRUE;
275 *((int *)va_arg (args, int *)) = p_sys->mtu;
278 case ACCESS_GET_PTS_DELAY:
279 *((int64_t *)va_arg (args, int64_t *)) = DEFAULT_PTS_DELAY;
282 case ACCESS_GET_TITLE_INFO:
283 case ACCESS_GET_META:
286 case ACCESS_SET_PAUSE_STATE:
289 case ACCESS_SET_TITLE:
290 case ACCESS_SET_SEEKPOINT:
291 case ACCESS_SET_PRIVATE_ID_STATE:
292 case ACCESS_SET_PRIVATE_ID_CA:
293 case ACCESS_GET_PRIVATE_ID_STATE:
294 case ACCESS_GET_CONTENT_TYPE:
298 msg_Warn (p_access, "unimplemented query %d in control", query);