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)
60 set_callbacks (Open, Close)
61 add_bool ("file-mmap", false, NULL,
62 FILE_MMAP_TEXT, FILE_MMAP_LONGTEXT, true);
65 static block_t *Block (access_t *);
66 static int Seek (access_t *, int64_t);
67 static int Control (access_t *, int, va_list);
76 #define MMAP_SIZE (1 << 20)
78 static int Open (vlc_object_t *p_this)
80 access_t *p_access = (access_t *)p_this;
82 const char *path = p_access->psz_path;
85 assert ((INT64_C(1) << 63) == ((off_t)(INT64_C(1) << 63)));
87 if (!var_CreateGetBool (p_this, "file-mmap"))
88 return VLC_EGENERIC; /* disabled */
90 STANDARD_BLOCK_ACCESS_INIT;
92 if (!strcmp (p_access->psz_path, "-"))
96 msg_Dbg (p_access, "opening file %s", path);
97 fd = utf8_open (path, O_RDONLY | O_NOCTTY, 0666);
102 msg_Warn (p_access, "cannot open %s: %m", path);
106 /* mmap() is only safe for regular and block special files.
107 * For other types, it may be some idiosyncrasic interface (e.g. packet
108 * sockets are a good example), if it works at all. */
113 msg_Err (p_access, "cannot stat %s: %m", path);
117 if (!S_ISREG (st.st_mode) && !S_ISBLK (st.st_mode))
119 msg_Dbg (p_access, "skipping non regular file %s", path);
123 #if defined(HAVE_FCNTL_H)
124 /* We'd rather use any available memory for reading ahead
125 * than for caching what we've already mmap'ed */
126 # if defined(F_RDAHEAD)
127 fcntl (fd, F_RDAHEAD, 1);
129 # if defined(F_NOCACHE)
130 fcntl (fd, F_NOCACHE, 1);
134 /* Autodetect mmap() support */
137 void *addr = mmap (NULL, 1, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
138 if (addr != MAP_FAILED)
144 p_sys->page_size = sysconf (_SC_PAGE_SIZE);
145 p_sys->mtu = MMAP_SIZE;
146 if (p_sys->mtu < p_sys->page_size)
147 p_sys->mtu = p_sys->page_size;
150 p_access->info.i_size = st.st_size;
151 #ifdef HAVE_POSIX_FADVISE
152 posix_fadvise (fd, 0, 0, POSIX_FADV_SEQUENTIAL);
165 static void Close (vlc_object_t * p_this)
167 access_t *p_access = (access_t *)p_this;
168 access_sys_t *p_sys = p_access->p_sys;
170 close (p_sys->fd); /* don't care about error when only reading */
174 static block_t *Block (access_t *p_access)
176 access_sys_t *p_sys = p_access->p_sys;
178 /* Check if file size changed... */
181 if ((fstat (p_sys->fd, &st) == 0)
182 && (st.st_size != p_access->info.i_size))
184 p_access->info.i_size = st.st_size;
185 p_access->info.i_update |= INPUT_UPDATE_SIZE;
188 if ((uint64_t)p_access->info.i_pos >= (uint64_t)p_access->info.i_size)
190 /* We are at end of file */
191 p_access->info.b_eof = true;
192 msg_Dbg (p_access, "at end of memory mapped file");
197 int64_t dbgpos = lseek (p_sys->fd, 0, SEEK_CUR);
198 if (dbgpos != p_access->info.i_pos)
199 msg_Err (p_access, "position: 0x%016"PRIx64" instead of 0x%016"PRIx64,
200 p_access->info.i_pos, dbgpos);
203 const uintptr_t page_mask = p_sys->page_size - 1;
204 /* Start the mapping on a page boundary: */
205 off_t outer_offset = p_access->info.i_pos & ~(off_t)page_mask;
206 /* Skip useless bytes at the beginning of the first page: */
207 size_t inner_offset = p_access->info.i_pos & page_mask;
208 /* Map no more bytes than remain: */
209 size_t length = p_sys->mtu;
210 if (outer_offset + length > p_access->info.i_size)
211 length = p_access->info.i_size - outer_offset;
213 assert (outer_offset <= p_access->info.i_pos); /* and */
214 assert (p_access->info.i_pos < p_access->info.i_size); /* imply */
215 assert (outer_offset < p_access->info.i_size); /* imply */
218 /* NOTE: We use PROT_WRITE and MAP_PRIVATE so that the block can be
219 * modified down the chain, without messing up with the underlying
220 * original file. This does NOT need open write permission. */
221 void *addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE
225 , p_sys->fd, outer_offset);
226 if (addr == MAP_FAILED)
228 msg_Err (p_access, "memory mapping failed (%m)");
229 intf_UserFatal (p_access, false, _("File reading failed"),
230 _("VLC could not read the file."));
233 #ifdef HAVE_POSIX_MADVISE
234 posix_madvise (addr, length, POSIX_MADV_SEQUENTIAL);
237 block_t *block = block_mmap_Alloc (addr, length);
241 block->p_buffer += inner_offset;
242 block->i_buffer -= inner_offset;
245 msg_Dbg (p_access, "mapped 0x%zx bytes at %p from offset 0x%"PRIx64,
246 length, addr, (uint64_t)outer_offset);
248 /* Compare normal I/O with memory mapping */
249 char *buf = malloc (block->i_buffer);
250 ssize_t i_read = read (p_sys->fd, buf, block->i_buffer);
252 if (i_read != (ssize_t)block->i_buffer)
253 msg_Err (p_access, "read %zd instead of %zu bytes", i_read,
255 if (memcmp (buf, block->p_buffer, block->i_buffer))
256 msg_Err (p_access, "inconsistent data buffer");
260 p_access->info.i_pos = outer_offset + length;
264 p_access->info.b_eof = true;
269 static int Seek (access_t *p_access, int64_t i_pos)
272 lseek (p_access->p_sys->fd, i_pos, SEEK_SET);
275 p_access->info.i_pos = i_pos;
276 p_access->info.b_eof = false;
281 static int Control (access_t *p_access, int query, va_list args)
283 access_sys_t *p_sys = p_access->p_sys;
287 case ACCESS_CAN_SEEK:
288 case ACCESS_CAN_FASTSEEK:
289 case ACCESS_CAN_PAUSE:
290 case ACCESS_CAN_CONTROL_PACE:
291 *((bool *)va_arg (args, bool *)) = true;
294 case ACCESS_GET_PTS_DELAY:
296 int delay_ms = var_CreateGetInteger (p_access, "file-caching");
297 *((int64_t *)va_arg (args, int64_t *)) = delay_ms * INT64_C (1000);
301 case ACCESS_GET_TITLE_INFO:
302 case ACCESS_GET_META:
305 case ACCESS_SET_PAUSE_STATE:
308 case ACCESS_SET_TITLE:
309 case ACCESS_SET_SEEKPOINT:
310 case ACCESS_SET_PRIVATE_ID_STATE:
311 case ACCESS_SET_PRIVATE_ID_CA:
312 case ACCESS_GET_PRIVATE_ID_STATE:
313 case ACCESS_GET_CONTENT_TYPE:
317 msg_Warn (p_access, "unimplemented query %d in control", query);