diff options
Diffstat (limited to 'source3/locking/shmem_sysv.c')
| -rw-r--r-- | source3/locking/shmem_sysv.c | 724 |
1 files changed, 0 insertions, 724 deletions
diff --git a/source3/locking/shmem_sysv.c b/source3/locking/shmem_sysv.c deleted file mode 100644 index 04a2e74460..0000000000 --- a/source3/locking/shmem_sysv.c +++ /dev/null @@ -1,724 +0,0 @@ -/* - Unix SMB/Netbios implementation. - Version 1.9. - Shared memory functions - SYSV IPC implementation - Copyright (C) Andrew Tridgell 1997-1998 - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 2 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. - -*/ - -#include "includes.h" - - -#ifdef USE_SYSV_IPC - -extern int DEBUGLEVEL; - -#define SHMEM_KEY ((key_t)0x280267) -#define SEMAPHORE_KEY (SHMEM_KEY+2) - -#define SHM_MAGIC 0x53484100 -#define SHM_VERSION 2 - -#ifdef SHM_R -#define IPC_PERMS ((SHM_R | SHM_W) | (SHM_R>>3) | (SHM_R>>6)) -#else -#define IPC_PERMS 0644 -#endif - - -#ifdef SECURE_SEMAPHORES -/* secure semaphores are slow because we have to do a become_root() - on every call! */ -#define SEMAPHORE_PERMS IPC_PERMS -#else -#define SEMAPHORE_PERMS 0666 -#endif - -#define SHMEM_HASH_SIZE 13 - -#define MIN_SHM_SIZE 0x1000 - -static int shm_id; -static int sem_id; -static int shm_size; -static int hash_size; -static int global_lock_count; - -struct ShmHeader { - int shm_magic; - int shm_version; - int total_size; /* in bytes */ - BOOL consistent; - int first_free_off; - int userdef_off; /* a userdefined offset. can be used to store - root of tree or list */ - struct { /* a cell is a range of bytes of sizeof(struct - ShmBlockDesc) size */ - int cells_free; - int cells_used; - int cells_system; /* number of cells used as allocated - block descriptors */ - } statistics; -}; - -#define SHM_NOT_FREE_OFF (-1) -struct ShmBlockDesc -{ - int next; /* offset of next block in the free list or - SHM_NOT_FREE_OFF when block in use */ - int size; /* user size in BlockDescSize units */ -}; - -#define EOList_Addr NULL -#define EOList_Off (0) - -#define CellSize sizeof(struct ShmBlockDesc) - -/* HeaderSize aligned on a 8 byte boundary */ -#define AlignedHeaderSize ((sizeof(struct ShmHeader)+7) & ~7) - -static struct ShmHeader *shm_header_p = NULL; - -static int read_only; - -static BOOL sem_change(int i, int op) -{ -#ifdef SECURE_SEMAPHORES - extern struct current_user current_user; - int became_root=0; -#endif - struct sembuf sb; - int ret; - - if (read_only) return True; - -#ifdef SECURE_SEMAPHORES - if (current_user.uid != 0) { - become_root(0); - became_root = 1; - } -#endif - - sb.sem_num = i; - sb.sem_op = op; - sb.sem_flg = 0; - - ret = semop(sem_id, &sb, 1); - - if (ret != 0) { - DEBUG(0,("ERROR: sem_change(%d,%d) failed (%s)\n", - i, op, strerror(errno))); - } - -#ifdef SECURE_SEMAPHORES - if (became_root) { - unbecome_root(0); - } -#endif - - return ret == 0; -} - -static BOOL global_lock(void) -{ - global_lock_count++; - if (global_lock_count == 1) - return sem_change(0, -1); - return True; -} - -static BOOL global_unlock(void) -{ - global_lock_count--; - if (global_lock_count == 0) - return sem_change(0, 1); - return True; -} - -static void *shm_offset2addr(int offset) -{ - if (offset == 0 ) - return (void *)(0); - - if (!shm_header_p) - return (void *)(0); - - return (void *)((char *)shm_header_p + offset); -} - -static int shm_addr2offset(void *addr) -{ - if (!addr) - return 0; - - if (!shm_header_p) - return 0; - - return (int)((char *)addr - (char *)shm_header_p); -} - - -static int shm_alloc(int size) -{ - unsigned num_cells ; - struct ShmBlockDesc *scanner_p; - struct ShmBlockDesc *prev_p; - struct ShmBlockDesc *new_p; - int result_offset; - - - if (!shm_header_p) { - /* not mapped yet */ - DEBUG(0,("ERROR shm_alloc : shmem not mapped\n")); - return 0; - } - - global_lock(); - - if (!shm_header_p->consistent) { - DEBUG(0,("ERROR shm_alloc : shmem not consistent\n")); - global_unlock(); - return 0; - } - - /* calculate the number of cells */ - num_cells = (size + (CellSize-1)) / CellSize; - - /* set start of scan */ - prev_p = (struct ShmBlockDesc *)shm_offset2addr(shm_header_p->first_free_off); - scanner_p = prev_p ; - - /* scan the free list to find a matching free space */ - while ((scanner_p != EOList_Addr) && (scanner_p->size < num_cells)) { - prev_p = scanner_p; - scanner_p = (struct ShmBlockDesc *)shm_offset2addr(scanner_p->next); - } - - /* at this point scanner point to a block header or to the end of - the list */ - if (scanner_p == EOList_Addr) { - DEBUG(0,("ERROR shm_alloc : alloc of %d bytes failed\n",size)); - global_unlock(); - return (0); - } - - /* going to modify shared mem */ - shm_header_p->consistent = False; - - /* if we found a good one : scanner == the good one */ - if (scanner_p->size > num_cells + 2) { - /* Make a new one */ - new_p = scanner_p + 1 + num_cells; - new_p->size = scanner_p->size - (num_cells + 1); - new_p->next = scanner_p->next; - scanner_p->size = num_cells; - scanner_p->next = shm_addr2offset(new_p); - - shm_header_p->statistics.cells_free -= 1; - shm_header_p->statistics.cells_system += 1; - } - - /* take it from the free list */ - if (prev_p == scanner_p) { - shm_header_p->first_free_off = scanner_p->next; - } else { - prev_p->next = scanner_p->next; - } - shm_header_p->statistics.cells_free -= scanner_p->size; - shm_header_p->statistics.cells_used += scanner_p->size; - - result_offset = shm_addr2offset(&(scanner_p[1])); - scanner_p->next = SHM_NOT_FREE_OFF; - - /* end modification of shared mem */ - shm_header_p->consistent = True; - - global_unlock(); - - DEBUG(6,("shm_alloc : allocated %d bytes at offset %d\n", - size,result_offset)); - - return result_offset; -} - -static void shm_solve_neighbors(struct ShmBlockDesc *head_p ) -{ - struct ShmBlockDesc *next_p; - - /* Check if head_p and head_p->next are neighbors and if so - join them */ - if ( head_p == EOList_Addr ) return ; - if ( head_p->next == EOList_Off ) return ; - - next_p = (struct ShmBlockDesc *)shm_offset2addr(head_p->next); - if ((head_p + head_p->size + 1) == next_p) { - head_p->size += next_p->size + 1; /* adapt size */ - head_p->next = next_p->next; /* link out */ - - shm_header_p->statistics.cells_free += 1; - shm_header_p->statistics.cells_system -= 1; - } -} - - -static BOOL shm_free(int offset) -{ - struct ShmBlockDesc *header_p; /* pointer to header of - block to free */ - struct ShmBlockDesc *scanner_p; /* used to scan the list */ - struct ShmBlockDesc *prev_p; /* holds previous in the - list */ - - if (!shm_header_p) { - /* not mapped yet */ - DEBUG(0,("ERROR shm_free : shmem not mapped\n")); - return False; - } - - global_lock(); - - if (!shm_header_p->consistent) { - DEBUG(0,("ERROR shm_free : shmem not consistent\n")); - global_unlock(); - return False; - } - - /* make pointer to header of block */ - header_p = ((struct ShmBlockDesc *)shm_offset2addr(offset) - 1); - - if (header_p->next != SHM_NOT_FREE_OFF) { - DEBUG(0,("ERROR shm_free : bad offset (%d)\n",offset)); - global_unlock(); - return False; - } - - /* find a place in the free_list to put the header in */ - - /* set scanner and previous pointer to start of list */ - prev_p = (struct ShmBlockDesc *) - shm_offset2addr(shm_header_p->first_free_off); - scanner_p = prev_p ; - - while ((scanner_p != EOList_Addr) && - (scanner_p < header_p)) { - /* while we didn't scan past its position */ - prev_p = scanner_p ; - scanner_p = (struct ShmBlockDesc *) - shm_offset2addr(scanner_p->next); - } - - shm_header_p->consistent = False; - - DEBUG(6,("shm_free : freeing %d bytes at offset %d\n", - (int)(header_p->size*CellSize),(int)offset)); - - /* zero the area being freed - this allows us to find bugs faster */ - memset(shm_offset2addr(offset), 0, header_p->size*CellSize); - - if (scanner_p == prev_p) { - shm_header_p->statistics.cells_free += header_p->size; - shm_header_p->statistics.cells_used -= header_p->size; - - /* we must free it at the beginning of the list */ - shm_header_p->first_free_off = shm_addr2offset(header_p); - /* set the free_list_pointer to this block_header */ - - /* scanner is the one that was first in the list */ - header_p->next = shm_addr2offset(scanner_p); - shm_solve_neighbors(header_p); - - shm_header_p->consistent = True; - } else { - shm_header_p->statistics.cells_free += header_p->size; - shm_header_p->statistics.cells_used -= header_p->size; - - prev_p->next = shm_addr2offset(header_p); - header_p->next = shm_addr2offset(scanner_p); - shm_solve_neighbors(header_p) ; - shm_solve_neighbors(prev_p) ; - - shm_header_p->consistent = True; - } - - global_unlock(); - return True; -} - - -/* - * Function to create the hash table for the share mode entries. Called - * when smb shared memory is global locked. - */ -static BOOL shm_create_hash_table(unsigned int hash_entries) -{ - int size = hash_entries * sizeof(int); - - global_lock(); - shm_header_p->userdef_off = shm_alloc(size); - - if(shm_header_p->userdef_off == 0) { - DEBUG(0,("shm_create_hash_table: Failed to create hash table of size %d\n", - size)); - global_unlock(); - return False; - } - - /* Clear hash buckets. */ - memset(shm_offset2addr(shm_header_p->userdef_off), '\0', size); - global_unlock(); - return True; -} - - -static BOOL shm_validate_header(int size) -{ - if(!shm_header_p) { - /* not mapped yet */ - DEBUG(0,("ERROR shm_validate_header : shmem not mapped\n")); - return False; - } - - if(shm_header_p->shm_magic != SHM_MAGIC) { - DEBUG(0,("ERROR shm_validate_header : bad magic\n")); - return False; - } - - if(shm_header_p->shm_version != SHM_VERSION) { - DEBUG(0,("ERROR shm_validate_header : bad version %X\n", - shm_header_p->shm_version)); - return False; - } - - if(shm_header_p->total_size != size) { - DEBUG(0,("ERROR shmem size mismatch (old = %d, new = %d)\n", - shm_header_p->total_size,size)); - return False; - } - - if(!shm_header_p->consistent) { - DEBUG(0,("ERROR shmem not consistent\n")); - return False; - } - return True; -} - - -static BOOL shm_initialize(int size) -{ - struct ShmBlockDesc * first_free_block_p; - - DEBUG(5,("shm_initialize : initializing shmem size %d\n",size)); - - if( !shm_header_p ) { - /* not mapped yet */ - DEBUG(0,("ERROR shm_initialize : shmem not mapped\n")); - return False; - } - - shm_header_p->shm_magic = SHM_MAGIC; - shm_header_p->shm_version = SHM_VERSION; - shm_header_p->total_size = size; - shm_header_p->first_free_off = AlignedHeaderSize; - shm_header_p->userdef_off = 0; - - first_free_block_p = (struct ShmBlockDesc *) - shm_offset2addr(shm_header_p->first_free_off); - first_free_block_p->next = EOList_Off; - first_free_block_p->size = - (size - (AlignedHeaderSize+CellSize))/CellSize; - shm_header_p->statistics.cells_free = first_free_block_p->size; - shm_header_p->statistics.cells_used = 0; - shm_header_p->statistics.cells_system = 1; - - shm_header_p->consistent = True; - - return True; -} - -static BOOL shm_close( void ) -{ - return True; -} - - -static int shm_get_userdef_off(void) -{ - if (!shm_header_p) - return 0; - else - return shm_header_p->userdef_off; -} - - -/******************************************************************* - Lock a particular hash bucket entry. - ******************************************************************/ -static BOOL shm_lock_hash_entry(unsigned int entry) -{ - return sem_change(entry+1, -1); -} - -/******************************************************************* - Unlock a particular hash bucket entry. - ******************************************************************/ -static BOOL shm_unlock_hash_entry(unsigned int entry) -{ - return sem_change(entry+1, 1); -} - - -/******************************************************************* - Gather statistics on shared memory usage. - ******************************************************************/ -static BOOL shm_get_usage(int *bytes_free, - int *bytes_used, - int *bytes_overhead) -{ - if(!shm_header_p) { - /* not mapped yet */ - DEBUG(0,("ERROR shm_free : shmem not mapped\n")); - return False; - } - - *bytes_free = shm_header_p->statistics.cells_free * CellSize; - *bytes_used = shm_header_p->statistics.cells_used * CellSize; - *bytes_overhead = shm_header_p->statistics.cells_system * CellSize + - AlignedHeaderSize; - - return True; -} - - -/******************************************************************* -hash a number into a hash_entry - ******************************************************************/ -static unsigned shm_hash_size(void) -{ - return hash_size; -} - - -static struct shmem_ops shmops = { - shm_close, - shm_alloc, - shm_free, - shm_get_userdef_off, - shm_offset2addr, - shm_addr2offset, - shm_lock_hash_entry, - shm_unlock_hash_entry, - shm_get_usage, - shm_hash_size, -}; - -/******************************************************************* - open the shared memory - ******************************************************************/ - -struct shmem_ops *sysv_shm_open(int ronly) -{ - BOOL other_processes; - struct shmid_ds shm_ds; - struct semid_ds sem_ds; - union semun su; - int i; - pid_t pid; - struct passwd *root_pwd = sys_getpwuid((uid_t)0); - gid_t root_gid = root_pwd ? root_pwd->pw_gid : (gid_t)0; - - read_only = ronly; - - shm_size = lp_shmem_size(); - - DEBUG(4,("Trying sysv shmem open of size %d\n", shm_size)); - - /* first the semaphore */ - sem_id = semget(SEMAPHORE_KEY, 0, 0); - if (sem_id == -1) { - if (read_only) return NULL; - - hash_size = SHMEM_HASH_SIZE; - - while (hash_size > 1) { - sem_id = semget(SEMAPHORE_KEY, hash_size+1, - IPC_CREAT|IPC_EXCL| SEMAPHORE_PERMS); - if (sem_id != -1 || - (errno != EINVAL && errno != ENOSPC)) break; - hash_size -= 5; - } - - if (sem_id == -1) { - DEBUG(0,("Can't create or use semaphore [1]. Error was %s\n", - strerror(errno))); - return NULL; - } - - if (sem_id != -1) { - su.val = 1; - for (i=0;i<hash_size+1;i++) { - if (semctl(sem_id, i, SETVAL, su) != 0) { - DEBUG(1,("Failed to init semaphore %d. Error was %s\n", - i, strerror(errno))); - return NULL; - } - } - } - } - if (shm_id == -1) { - sem_id = semget(SEMAPHORE_KEY, 0, 0); - } - if (sem_id == -1) { - DEBUG(0,("Can't create or use semaphore [2]. Error was %s\n", - strerror(errno))); - return NULL; - } - - su.buf = &sem_ds; - if (semctl(sem_id, 0, IPC_STAT, su) != 0) { - DEBUG(0,("ERROR semctl: can't IPC_STAT. Error was %s\n", - strerror(errno))); - return NULL; - } - hash_size = sem_ds.sem_nsems-1; - - if (!read_only) { - if (sem_ds.sem_perm.cuid != 0 || ((sem_ds.sem_perm.cgid != root_gid) && (sem_ds.sem_perm.cgid != 0))) { - DEBUG(0,("ERROR: root did not create the semaphore: semgid=%u, rootgid=%u\n", - (unsigned int)sem_ds.sem_perm.cgid, (unsigned int)root_gid)); - return NULL; - } - - if (semctl(sem_id, 0, GETVAL, su) == 0 && - !process_exists((pid=(pid_t)semctl(sem_id, 0, GETPID, su)))) { - DEBUG(0,("WARNING: clearing global IPC lock set by dead process %d\n", - (int)pid)); - su.val = 1; - if (semctl(sem_id, 0, SETVAL, su) != 0) { - DEBUG(0,("ERROR: Failed to clear global lock. Error was %s\n", - strerror(errno))); - return NULL; - } - } - - sem_ds.sem_perm.mode = SEMAPHORE_PERMS; - if (semctl(sem_id, 0, IPC_SET, su) != 0) { - DEBUG(0,("ERROR shmctl : can't IPC_SET. Error was %s\n", - strerror(errno))); - return NULL; - } - } - - if (!global_lock()) - return NULL; - - - for (i=1;i<hash_size+1;i++) { - if (semctl(sem_id, i, GETVAL, su) == 0 && - !process_exists((pid=(pid_t)semctl(sem_id, i, GETPID, su)))) { - DEBUG(1,("WARNING: clearing IPC lock %d set by dead process %d\n", - i, (int)pid)); - su.val = 1; - if (semctl(sem_id, i, SETVAL, su) != 0) { - DEBUG(0,("ERROR: Failed to clear IPC lock %d. Error was %s\n", - i, strerror(errno))); - global_unlock(); - return NULL; - } - } - } - - /* - * Try to use an existing key. Note that - * in order to use an existing key successfully - * size must be zero else shmget returns EINVAL. - * Thanks to Veselin Terzic <vterzic@systems.DHL.COM> - * for pointing this out. - */ - - shm_id = shmget(SHMEM_KEY, 0, 0); - - /* if that failed then create one */ - if (shm_id == -1) { - if (read_only) return NULL; - while (shm_size > MIN_SHM_SIZE) { - shm_id = shmget(SHMEM_KEY, shm_size, - IPC_CREAT | IPC_EXCL | IPC_PERMS); - if (shm_id != -1 || - (errno != EINVAL && errno != ENOSPC)) break; - shm_size *= 0.8; - } - } - - if (shm_id == -1) { - DEBUG(0,("Can't create or use IPC area. Error was %s\n", strerror(errno))); - global_unlock(); - return NULL; - } - - - shm_header_p = (struct ShmHeader *)shmat(shm_id, 0, - read_only?SHM_RDONLY:0); - if ((long)shm_header_p == -1) { - DEBUG(0,("Can't attach to IPC area. Error was %s\n", strerror(errno))); - global_unlock(); - return NULL; - } - - /* to find out if some other process is already mapping the file, - we use a registration file containing the processids of the file - mapping processes */ - if (shmctl(shm_id, IPC_STAT, &shm_ds) != 0) { - DEBUG(0,("ERROR shmctl : can't IPC_STAT. Error was %s\n", strerror(errno))); - global_unlock(); - return NULL; - } - - if (!read_only) { - if (shm_ds.shm_perm.cuid != 0 || ((shm_ds.shm_perm.cgid != root_gid) && (shm_ds.shm_perm.cgid != 0))) { - DEBUG(0,("ERROR: root did not create the shmem\n")); - global_unlock(); - return NULL; - } - } - - shm_size = shm_ds.shm_segsz; - - other_processes = (shm_ds.shm_nattch > 1); - - if (!read_only && !other_processes) { - memset((char *)shm_header_p, 0, shm_size); - shm_initialize(shm_size); - shm_create_hash_table(hash_size); - DEBUG(3,("Initialised IPC area of size %d\n", shm_size)); - } else if (!shm_validate_header(shm_size)) { - /* existing file is corrupt, samba admin should remove - it by hand */ - DEBUG(0,("ERROR shm_open : corrupt IPC area - remove it!\n")); - global_unlock(); - return NULL; - } - - global_unlock(); - return &shmops; -} - - - -#else - int ipc_dummy_procedure(void) -{return 0;} -#endif |