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 posix_fadvise (fd, 0, 0, POSIX_FADV_SEQUENTIAL);
146 static void Close (vlc_object_t * p_this)
148 access_t *p_access = (access_t *)p_this;
149 access_sys_t *p_sys = p_access->p_sys;
151 close (p_sys->fd); /* don't care about error when only reading */
155 static block_t *Block (access_t *p_access)
157 access_sys_t *p_sys = p_access->p_sys;
159 int64_t dbgpos = lseek (p_sys->fd, 0, SEEK_CUR);
160 if (dbgpos != p_access->info.i_pos)
161 msg_Err (p_access, "position: 0x%08llx instead of 0x%08llx",
162 p_access->info.i_pos, dbgpos);
165 if ((uint64_t)p_access->info.i_pos >= (uint64_t)p_access->info.i_size)
167 /* End of file - check if file size changed... */
170 if ((fstat (p_sys->fd, &st) == 0)
171 && (st.st_size != p_access->info.i_size))
173 p_access->info.i_size = st.st_size;
174 p_access->info.i_update |= INPUT_UPDATE_SIZE;
177 /* Really at end of file then */
178 if ((uint64_t)p_access->info.i_pos >= (uint64_t)p_access->info.i_size)
180 p_access->info.b_eof = VLC_TRUE;
181 msg_Dbg (p_access, "at end of memory mapped file");
186 const uintptr_t page_mask = p_sys->page_size - 1;
187 /* Start the mapping on a page boundary: */
188 off_t outer_offset = p_access->info.i_pos & ~page_mask;
189 /* Skip useless bytes at the beginning of the first page: */
190 size_t inner_offset = p_access->info.i_pos & page_mask;
191 /* Map no more bytes than remain: */
192 size_t length = p_sys->mtu;
193 if (outer_offset + length > p_access->info.i_size)
194 length = p_access->info.i_size - outer_offset;
196 assert (outer_offset <= p_access->info.i_pos); /* and */
197 assert (p_access->info.i_pos < p_access->info.i_size); /* imply */
198 assert (outer_offset < p_access->info.i_size); /* imply */
201 /* NOTE: We use PROT_WRITE and MAP_PRIVATE so that the block can be
202 * modified down the chain, without messing up with the underlying
203 * original file. This does NOT need open write permission. */
204 void *addr = mmap (NULL, length, PROT_READ|PROT_WRITE, MAP_PRIVATE,
205 p_sys->fd, outer_offset);
206 if (addr == MAP_FAILED)
208 msg_Err (p_access, "memory mapping failed (%m)");
209 intf_UserFatal (p_access, VLC_FALSE, _("File reading failed"),
210 _("VLC could not read the file."));
211 msleep (INPUT_ERROR_SLEEP);
214 posix_madvise (addr, length, POSIX_MADV_SEQUENTIAL);
216 block_t *block = block_mmap_Alloc (addr, length);
220 block->p_buffer += inner_offset;
221 block->i_buffer -= inner_offset;
224 msg_Dbg (p_access, "mapped 0x%lx bytes at %p from offset 0x%lx",
225 (unsigned long)length, addr, (unsigned long)outer_offset);
227 /* Compare normal I/O with memory mapping */
228 char *buf = malloc (block->i_buffer);
229 ssize_t i_read = read (p_sys->fd, buf, block->i_buffer);
231 if (i_read != (ssize_t)block->i_buffer)
232 msg_Err (p_access, "read %u instead of %u bytes", (unsigned)i_read,
233 (unsigned)block->i_buffer);
234 if (memcmp (buf, block->p_buffer, block->i_buffer))
235 msg_Err (p_access, "inconsistent data buffer");
239 p_access->info.i_pos = outer_offset + length;
244 static int Seek (access_t *p_access, int64_t i_pos)
246 p_access->info.i_pos = i_pos;
247 p_access->info.b_eof = VLC_FALSE;
252 static int Control (access_t *p_access, int query, va_list args)
254 access_sys_t *p_sys = p_access->p_sys;
258 case ACCESS_CAN_SEEK:
259 case ACCESS_CAN_FASTSEEK:
260 case ACCESS_CAN_PAUSE:
261 case ACCESS_CAN_CONTROL_PACE:
262 *((vlc_bool_t *)va_arg (args, vlc_bool_t *)) = VLC_TRUE;
266 *((int *)va_arg (args, int *)) = p_sys->mtu;
269 case ACCESS_GET_PTS_DELAY:
270 *((int64_t *)va_arg (args, int64_t *)) = DEFAULT_PTS_DELAY;
273 case ACCESS_GET_TITLE_INFO:
274 case ACCESS_GET_META:
277 case ACCESS_SET_PAUSE_STATE:
280 case ACCESS_SET_TITLE:
281 case ACCESS_SET_SEEKPOINT:
282 case ACCESS_SET_PRIVATE_ID_STATE:
283 case ACCESS_SET_PRIVATE_ID_CA:
284 case ACCESS_GET_PRIVATE_ID_STATE:
285 case ACCESS_GET_CONTENT_TYPE:
289 msg_Warn (p_access, "unimplemented query %d in control", query);