2 Unix SMB/Netbios implementation.
4 Shared memory functions
5 Copyright (C) Erik Devriendt 1996-1997
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., 675 Mass Ave, Cambridge, MA 02139, USA.
26 #ifdef FAST_SHARE_MODES
29 extern int DEBUGLEVEL;
32 #define SMB_SHM_MAGIC 0x53484100
35 #define SMB_SHM_VERSION 2
37 /* we need world read for smbstatus to function correctly */
38 #ifdef SECURE_SHARE_MODES
39 #define SHM_FILE_MODE 0600
41 #define SHM_FILE_MODE 0644
44 #define SHMEM_HASH_SIZE 113
47 /* WARNING : offsets are used because mmap() does not guarantee that all processes have the
48 shared memory mapped to the same address */
54 int total_size; /* in bytes */
57 int userdef_off; /* a userdefined offset. can be used to store root of tree or list */
58 struct { /* a cell is a range of bytes of sizeof(struct SmbShmBlockDesc) size */
61 int cells_system; /* number of cells used as allocated block descriptors */
65 #define SMB_SHM_NOT_FREE_OFF (-1)
66 struct SmbShmBlockDesc
68 int next; /* offset of next block in the free list or SMB_SHM_NOT_FREE_OFF when block in use */
69 int size; /* user size in BlockDescSize units */
72 #define EOList_Addr (struct SmbShmBlockDesc *)( 0 )
73 #define EOList_Off (NULL_OFFSET)
75 #define CellSize sizeof(struct SmbShmBlockDesc)
77 /* HeaderSize aligned on 8 byte boundary */
78 #define AlignedHeaderSize ((sizeof(struct SmbShmHeader)+7) & ~7)
80 static int smb_shm_fd = -1;
81 static pstring smb_shm_processreg_name = "";
83 static struct SmbShmHeader *smb_shm_header_p = (struct SmbShmHeader *)0;
84 static int smb_shm_times_locked = 0;
86 static BOOL smb_shm_initialize_called = False;
90 static BOOL smb_shm_global_lock(void)
94 DEBUG(0,("ERROR smb_shm_global_lock : bad smb_shm_fd (%d)\n",smb_shm_fd));
98 smb_shm_times_locked++;
100 if(smb_shm_times_locked > 1)
102 DEBUG(5,("smb_shm_global_lock : locked %d times\n",smb_shm_times_locked));
109 /* Do an exclusive wait lock on the first byte of the file */
110 if (fcntl_lock(smb_shm_fd, F_SETLKW, 0, 1, F_WRLCK) == False)
112 DEBUG(0,("ERROR smb_shm_global_lock : fcntl_lock failed with code %s\n",strerror(errno)));
113 smb_shm_times_locked--;
121 static BOOL smb_shm_global_unlock(void)
125 DEBUG(0,("ERROR smb_shm_global_unlock : bad smb_shm_fd (%d)\n",smb_shm_fd));
129 if(smb_shm_times_locked == 0)
131 DEBUG(0,("ERROR smb_shm_global_unlock : shmem not locked\n",smb_shm_fd));
135 smb_shm_times_locked--;
137 if(smb_shm_times_locked > 0)
139 DEBUG(5,("smb_shm_global_unlock : still locked %d times\n",smb_shm_times_locked));
146 /* Do a wait unlock on the first byte of the file */
147 if (fcntl_lock(smb_shm_fd, F_SETLKW, 0, 1, F_UNLCK) == False)
149 DEBUG(0,("ERROR smb_shm_global_unlock : fcntl_lock failed with code %s\n",strerror(errno)));
150 smb_shm_times_locked++;
159 static void *smb_shm_offset2addr(int offset)
161 if (offset == NULL_OFFSET )
164 if (!smb_shm_header_p)
167 return (void *)((char *)smb_shm_header_p + offset );
170 static int smb_shm_addr2offset(void *addr)
175 if (!smb_shm_header_p)
178 return (int)((char *)addr - (char *)smb_shm_header_p);
183 static int smb_shm_alloc(int size)
186 struct SmbShmBlockDesc *scanner_p;
187 struct SmbShmBlockDesc *prev_p;
188 struct SmbShmBlockDesc *new_p;
192 if( !smb_shm_header_p )
195 DEBUG(0,("ERROR smb_shm_alloc : shmem not mapped\n"));
199 smb_shm_global_lock();
201 if( !smb_shm_header_p->consistent)
203 DEBUG(0,("ERROR smb_shm_alloc : shmem not consistent\n"));
204 smb_shm_global_unlock();
209 /* calculate the number of cells */
210 num_cells = (size + CellSize -1) / CellSize;
212 /* set start of scan */
213 prev_p = (struct SmbShmBlockDesc *)smb_shm_offset2addr(smb_shm_header_p->first_free_off);
216 /* scan the free list to find a matching free space */
217 while ( ( scanner_p != EOList_Addr ) && ( scanner_p->size < num_cells ) )
220 scanner_p = (struct SmbShmBlockDesc *)smb_shm_offset2addr(scanner_p->next);
223 /* at this point scanner point to a block header or to the end of the list */
224 if ( scanner_p == EOList_Addr )
226 DEBUG(0,("ERROR smb_shm_alloc : alloc of %d bytes failed, no free space found\n",size));
227 smb_shm_global_unlock();
228 return (NULL_OFFSET);
231 /* going to modify shared mem */
232 smb_shm_header_p->consistent = False;
234 /* if we found a good one : scanner == the good one */
235 if ( scanner_p->size <= num_cells + 2 )
237 /* there is no use in making a new one, it will be too small anyway
238 * we will link out scanner
240 if ( prev_p == scanner_p )
242 smb_shm_header_p->first_free_off = scanner_p->next ;
246 prev_p->next = scanner_p->next ;
248 smb_shm_header_p->statistics.cells_free -= scanner_p->size;
249 smb_shm_header_p->statistics.cells_used += scanner_p->size;
254 new_p = scanner_p + 1 + num_cells;
255 new_p->size = scanner_p->size - num_cells - 1;
256 new_p->next = scanner_p->next;
257 scanner_p->size = num_cells;
258 scanner_p->next = smb_shm_addr2offset(new_p);
260 if ( prev_p != scanner_p )
262 prev_p->next = smb_shm_addr2offset(new_p) ;
266 smb_shm_header_p->first_free_off = smb_shm_addr2offset(new_p) ;
268 smb_shm_header_p->statistics.cells_free -= num_cells+1;
269 smb_shm_header_p->statistics.cells_used += num_cells;
270 smb_shm_header_p->statistics.cells_system += 1;
273 result_offset = smb_shm_addr2offset( &(scanner_p[1]) );
274 scanner_p->next = SMB_SHM_NOT_FREE_OFF ;
276 /* end modification of shared mem */
277 smb_shm_header_p->consistent = True;
279 DEBUG(6,("smb_shm_alloc : request for %d bytes, allocated %d bytes at offset %d\n",size,scanner_p->size*CellSize,result_offset ));
281 smb_shm_global_unlock();
282 return ( result_offset );
289 * Function to create the hash table for the share mode entries. Called
290 * when smb shared memory is global locked.
292 static BOOL smb_shm_create_hash_table( unsigned int size )
296 smb_shm_global_lock();
297 smb_shm_header_p->userdef_off = smb_shm_alloc( size );
299 if(smb_shm_header_p->userdef_off == NULL_OFFSET)
301 DEBUG(0,("smb_shm_create_hash_table: Failed to create hash table of size %d\n",size));
302 smb_shm_global_unlock();
306 /* Clear hash buckets. */
307 memset( smb_shm_offset2addr(smb_shm_header_p->userdef_off), '\0', size);
308 smb_shm_global_unlock();
312 static BOOL smb_shm_register_process(char *processreg_file, pid_t pid, BOOL *other_processes)
314 int smb_shm_processes_fd = -1;
317 int seek_back = -((int)sizeof(other_pid));
321 smb_shm_processes_fd = open(processreg_file,
322 read_only?O_RDONLY:(O_RDWR|O_CREAT),
325 if ( smb_shm_processes_fd < 0 )
327 DEBUG(0,("ERROR smb_shm_register_process : processreg_file open failed with code %s\n",strerror(errno)));
331 *other_processes = False;
333 while ((nb_read = read(smb_shm_processes_fd, &other_pid, sizeof(other_pid))) > 0)
337 if(process_exists(other_pid))
338 *other_processes = True;
342 DEBUG(5,("smb_shm_register_process : erasing stale record for pid %d (seek_back = %d)\n",
343 other_pid, seek_back));
344 other_pid = (pid_t)0;
345 erased_slot = lseek(smb_shm_processes_fd, seek_back, SEEK_CUR);
346 write(smb_shm_processes_fd, &other_pid, sizeof(other_pid));
348 free_slot = erased_slot;
353 free_slot = lseek(smb_shm_processes_fd, seek_back, SEEK_CUR);
357 DEBUG(0,("ERROR smb_shm_register_process : processreg_file read failed with code %s\n",strerror(errno)));
358 close(smb_shm_processes_fd);
363 free_slot = lseek(smb_shm_processes_fd, 0, SEEK_END);
365 DEBUG(5,("smb_shm_register_process : writing record for pid %d at offset %d\n",pid,free_slot));
366 lseek(smb_shm_processes_fd, free_slot, SEEK_SET);
367 if(write(smb_shm_processes_fd, &pid, sizeof(pid)) < 0)
369 DEBUG(0,("ERROR smb_shm_register_process : processreg_file write failed with code %s\n",strerror(errno)));
370 close(smb_shm_processes_fd);
374 close(smb_shm_processes_fd);
379 static BOOL smb_shm_unregister_process(char *processreg_file, pid_t pid)
381 int smb_shm_processes_fd = -1;
384 int seek_back = -((int)sizeof(other_pid));
389 smb_shm_processes_fd = open(processreg_file, O_RDWR);
390 if ( smb_shm_processes_fd < 0 )
392 DEBUG(0,("ERROR smb_shm_unregister_process : processreg_file open failed with code %s\n",strerror(errno)));
396 while ((nb_read = read(smb_shm_processes_fd, &other_pid, sizeof(other_pid))) > 0)
398 DEBUG(5,("smb_shm_unregister_process : read record for pid %d\n",other_pid));
402 DEBUG(5,("smb_shm_unregister_process : erasing record for pid %d (seek_val = %d)\n",
403 other_pid, seek_back));
404 other_pid = (pid_t)0;
405 erased_slot = lseek(smb_shm_processes_fd, seek_back, SEEK_CUR);
406 if(write(smb_shm_processes_fd, &other_pid, sizeof(other_pid)) < 0)
408 DEBUG(0,("ERROR smb_shm_unregister_process : processreg_file write failed with code %s\n",strerror(errno)));
409 close(smb_shm_processes_fd);
419 DEBUG(0,("ERROR smb_shm_unregister_process : processreg_file read failed with code %s\n",strerror(errno)));
420 close(smb_shm_processes_fd);
426 DEBUG(0,("ERROR smb_shm_unregister_process : couldn't find pid %d in file %s\n",pid,processreg_file));
427 close(smb_shm_processes_fd);
432 close(smb_shm_processes_fd);
438 static BOOL smb_shm_validate_header(int size)
440 if( !smb_shm_header_p )
443 DEBUG(0,("ERROR smb_shm_validate_header : shmem not mapped\n"));
447 if(smb_shm_header_p->smb_shm_magic != SMB_SHM_MAGIC)
449 DEBUG(0,("ERROR smb_shm_validate_header : bad magic\n"));
452 if(smb_shm_header_p->smb_shm_version != SMB_SHM_VERSION)
454 DEBUG(0,("ERROR smb_shm_validate_header : bad version %X\n",smb_shm_header_p->smb_shm_version));
458 if(smb_shm_header_p->total_size != size)
460 DEBUG(0,("ERROR smb_shm_validate_header : shmem size mismatch (old = %d, new = %d)\n",smb_shm_header_p->total_size,size));
464 if(!smb_shm_header_p->consistent)
466 DEBUG(0,("ERROR smb_shm_validate_header : shmem not consistent\n"));
472 static BOOL smb_shm_initialize(int size)
474 struct SmbShmBlockDesc * first_free_block_p;
476 DEBUG(5,("smb_shm_initialize : initializing shmem file of size %d\n",size));
478 if( !smb_shm_header_p )
481 DEBUG(0,("ERROR smb_shm_initialize : shmem not mapped\n"));
485 smb_shm_header_p->smb_shm_magic = SMB_SHM_MAGIC;
486 smb_shm_header_p->smb_shm_version = SMB_SHM_VERSION;
487 smb_shm_header_p->total_size = size;
488 smb_shm_header_p->first_free_off = AlignedHeaderSize;
489 smb_shm_header_p->userdef_off = NULL_OFFSET;
491 first_free_block_p = (struct SmbShmBlockDesc *)smb_shm_offset2addr(smb_shm_header_p->first_free_off);
492 first_free_block_p->next = EOList_Off;
493 first_free_block_p->size = ( size - AlignedHeaderSize - CellSize ) / CellSize ;
495 smb_shm_header_p->statistics.cells_free = first_free_block_p->size;
496 smb_shm_header_p->statistics.cells_used = 0;
497 smb_shm_header_p->statistics.cells_system = 1;
499 smb_shm_header_p->consistent = True;
501 smb_shm_initialize_called = True;
506 static void smb_shm_solve_neighbors(struct SmbShmBlockDesc *head_p )
508 struct SmbShmBlockDesc *next_p;
510 /* Check if head_p and head_p->next are neighbors and if so join them */
511 if ( head_p == EOList_Addr ) return ;
512 if ( head_p->next == EOList_Off ) return ;
514 next_p = (struct SmbShmBlockDesc *)smb_shm_offset2addr(head_p->next);
515 if ( ( head_p + head_p->size + 1 ) == next_p)
517 head_p->size += next_p->size +1 ; /* adapt size */
518 head_p->next = next_p->next ; /* link out */
520 smb_shm_header_p->statistics.cells_free += 1;
521 smb_shm_header_p->statistics.cells_system -= 1;
527 static BOOL smb_shm_close( void )
530 if(smb_shm_initialize_called == False)
533 DEBUG(5,("smb_shm_close\n"));
534 if(smb_shm_times_locked > 0)
535 DEBUG(0,("WARNING smb_shm_close : shmem was still locked %d times\n",smb_shm_times_locked));;
536 if ((smb_shm_header_p != NULL) &&
537 (munmap((caddr_t)smb_shm_header_p, smb_shm_header_p->total_size) < 0))
539 DEBUG(0,("ERROR smb_shm_close : munmap failed with code %s\n",strerror(errno)));
542 smb_shm_global_lock();
543 DEBUG(5,("calling smb_shm_unregister_process(%s, %d)\n", smb_shm_processreg_name, getpid()));
544 smb_shm_unregister_process(smb_shm_processreg_name, getpid());
545 smb_shm_global_unlock();
550 smb_shm_processreg_name[0] = '\0';
552 smb_shm_header_p = (struct SmbShmHeader *)0;
553 smb_shm_times_locked = 0;
559 static BOOL smb_shm_free(int offset)
561 struct SmbShmBlockDesc *header_p ; /* pointer to header of block to free */
562 struct SmbShmBlockDesc *scanner_p ; /* used to scan the list */
563 struct SmbShmBlockDesc *prev_p ; /* holds previous in the list */
565 if( !smb_shm_header_p )
568 DEBUG(0,("ERROR smb_shm_free : shmem not mapped\n"));
572 smb_shm_global_lock();
574 if( !smb_shm_header_p->consistent)
576 DEBUG(0,("ERROR smb_shm_free : shmem not consistent\n"));
577 smb_shm_global_unlock();
581 header_p = ( (struct SmbShmBlockDesc *)smb_shm_offset2addr(offset) - 1); /* make pointer to header of block */
583 if (header_p->next != SMB_SHM_NOT_FREE_OFF)
585 DEBUG(0,("ERROR smb_shm_free : bad offset (%d)\n",offset));
586 smb_shm_global_unlock();
590 /* find a place in the free_list to put the header in */
592 /* set scanner and previous pointer to start of list */
593 prev_p = (struct SmbShmBlockDesc *)smb_shm_offset2addr(smb_shm_header_p->first_free_off);
596 while ( ( scanner_p != EOList_Addr) && (scanner_p < header_p) ) /* while we didn't scan past its position */
599 scanner_p = (struct SmbShmBlockDesc *)smb_shm_offset2addr(scanner_p->next);
602 smb_shm_header_p->consistent = False;
604 DEBUG(6,("smb_shm_free : freeing %d bytes at offset %d\n",header_p->size*CellSize,offset));
606 if ( scanner_p == prev_p )
608 smb_shm_header_p->statistics.cells_free += header_p->size;
609 smb_shm_header_p->statistics.cells_used -= header_p->size;
611 /* we must free it at the beginning of the list */
612 smb_shm_header_p->first_free_off = smb_shm_addr2offset(header_p); /* set the free_list_pointer to this block_header */
614 /* scanner is the one that was first in the list */
615 header_p->next = smb_shm_addr2offset(scanner_p);
616 smb_shm_solve_neighbors( header_p ); /* if neighbors then link them */
618 smb_shm_header_p->consistent = True;
619 smb_shm_global_unlock();
624 smb_shm_header_p->statistics.cells_free += header_p->size;
625 smb_shm_header_p->statistics.cells_used -= header_p->size;
627 prev_p->next = smb_shm_addr2offset(header_p);
628 header_p->next = smb_shm_addr2offset(scanner_p);
629 smb_shm_solve_neighbors(header_p) ;
630 smb_shm_solve_neighbors(prev_p) ;
632 smb_shm_header_p->consistent = True;
633 smb_shm_global_unlock();
638 static int smb_shm_get_userdef_off(void)
640 if (!smb_shm_header_p)
643 return smb_shm_header_p->userdef_off;
646 /*******************************************************************
647 Lock a particular hash bucket entry.
648 ******************************************************************/
649 static BOOL smb_shm_lock_hash_entry( unsigned int entry)
651 int start = (smb_shm_header_p->userdef_off + (entry * sizeof(int)));
655 DEBUG(0,("ERROR smb_shm_lock_hash_entry : bad smb_shm_fd (%d)\n",smb_shm_fd));
659 /* Do an exclusive wait lock on the 4 byte region mapping into this entry */
660 if (fcntl_lock(smb_shm_fd, F_SETLKW, start, sizeof(int), F_WRLCK) == False)
662 DEBUG(0,("ERROR smb_shm_lock_hash_entry : fcntl_lock failed with code %s\n",strerror(errno)));
666 DEBUG(9,("smb_shm_lock_hash_entry: locked hash bucket %d\n", entry));
670 /*******************************************************************
671 Unlock a particular hash bucket entry.
672 ******************************************************************/
673 static BOOL smb_shm_unlock_hash_entry( unsigned int entry )
675 int start = (smb_shm_header_p->userdef_off + (entry * sizeof(int)));
679 DEBUG(0,("ERROR smb_shm_unlock_hash_entry : bad smb_shm_fd (%d)\n",smb_shm_fd));
683 /* Do a wait lock on the 4 byte region mapping into this entry */
684 if (fcntl_lock(smb_shm_fd, F_SETLKW, start, sizeof(int), F_UNLCK) == False)
686 DEBUG(0,("ERROR smb_shm_unlock_hash_entry : fcntl_lock failed with code %s\n",strerror(errno)));
690 DEBUG(9,("smb_shm_unlock_hash_entry: unlocked hash bucket %d\n", entry));
694 /*******************************************************************
695 Gather statistics on shared memory usage.
696 ******************************************************************/
697 static BOOL smb_shm_get_usage(int *bytes_free,
701 if( !smb_shm_header_p )
704 DEBUG(0,("ERROR smb_shm_free : shmem not mapped\n"));
707 *bytes_free = smb_shm_header_p->statistics.cells_free * CellSize;
708 *bytes_used = smb_shm_header_p->statistics.cells_used * CellSize;
709 *bytes_overhead = smb_shm_header_p->statistics.cells_system * CellSize + AlignedHeaderSize;
714 /*******************************************************************
715 hash a number into a hash_entry
716 ******************************************************************/
717 static unsigned smb_shm_hash_size(void)
719 return SHMEM_HASH_SIZE;
722 static struct shmem_ops shmops = {
726 smb_shm_get_userdef_off,
729 smb_shm_lock_hash_entry,
730 smb_shm_unlock_hash_entry,
735 /*******************************************************************
736 open the shared memory
737 ******************************************************************/
738 struct shmem_ops *smb_shm_open(int ronly)
742 BOOL created_new = False;
743 BOOL other_processes = True;
744 int size = lp_shmem_size();
748 pstrcpy(file_name,lp_lockdir());
749 if (!directory_exist(file_name,NULL)) {
750 if (read_only) return NULL;
751 mkdir(file_name,0755);
753 trim_string(file_name,"","/");
754 if (!*file_name) return(False);
755 strcat(file_name, "/SHARE_MEM_FILE");
757 DEBUG(5,("smb_shm_open : using shmem file %s to be of size %d\n",file_name,size));
759 smb_shm_fd = open(file_name, read_only?O_RDONLY:(O_RDWR|O_CREAT),
762 if ( smb_shm_fd < 0 )
764 DEBUG(0,("ERROR smb_shm_open : open failed with code %s\n",strerror(errno)));
768 if (!smb_shm_global_lock())
770 DEBUG(0,("ERROR smb_shm_open : can't do smb_shm_global_lock\n"));
774 if( (filesize = lseek(smb_shm_fd, 0, SEEK_END)) < 0)
776 DEBUG(0,("ERROR smb_shm_open : lseek failed with code %s\n",strerror(errno)));
777 smb_shm_global_unlock();
782 /* return the file offset to 0 to save on later seeks */
783 lseek(smb_shm_fd,0,SEEK_SET);
787 /* we just created a new one */
791 /* to find out if some other process is already mapping the file,
792 we use a registration file containing the processids of the file mapping processes
795 /* construct processreg file name */
796 strcpy(smb_shm_processreg_name, file_name);
797 strcat(smb_shm_processreg_name, ".processes");
800 !smb_shm_register_process(smb_shm_processreg_name, getpid(), &other_processes))
802 smb_shm_global_unlock();
807 if (!read_only && (created_new || !other_processes))
809 /* we just created a new one, or are the first opener, lets set it size */
810 if( ftruncate(smb_shm_fd, size) <0)
812 DEBUG(0,("ERROR smb_shm_open : ftruncate failed with code %s\n",strerror(errno)));
813 smb_shm_unregister_process(smb_shm_processreg_name, getpid());
814 smb_shm_global_unlock();
820 lseek(smb_shm_fd,0,SEEK_SET);
825 if (size != filesize )
827 /* the existing file has a different size and we are not the first opener.
828 Since another process is still using it, we will use the file size */
829 DEBUG(0,("WARNING smb_shm_open : filesize (%d) != expected size (%d), using filesize\n",filesize,size));
833 smb_shm_header_p = (struct SmbShmHeader *)mmap(NULL, size,
835 (PROT_READ | PROT_WRITE),
836 MAP_FILE | MAP_SHARED,
838 /* WARNING, smb_shm_header_p can be different for different processes mapping the same file ! */
839 if (smb_shm_header_p == (struct SmbShmHeader *)(-1))
841 DEBUG(0,("ERROR smb_shm_open : mmap failed with code %s\n",strerror(errno)));
842 smb_shm_unregister_process(smb_shm_processreg_name, getpid());
843 smb_shm_global_unlock();
849 if (!read_only && (created_new || !other_processes))
851 smb_shm_initialize(size);
852 /* Create the hash buckets for the share file entries. */
853 smb_shm_create_hash_table(SHMEM_HASH_SIZE);
855 else if (!smb_shm_validate_header(size) )
857 /* existing file is corrupt, samba admin should remove it by hand */
858 DEBUG(0,("ERROR smb_shm_open : corrupt shared mem file, remove it manually\n"));
859 munmap((caddr_t)smb_shm_header_p, size);
860 smb_shm_unregister_process(smb_shm_processreg_name, getpid());
861 smb_shm_global_unlock();
866 smb_shm_global_unlock();
871 #else /* FAST_SHARE_MODES */
872 int shmem_dummy_procedure(void)
874 #endif /* FAST_SHARE_MODES */