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-rw-r--r--source3/locking/shmem_sysv.c621
1 files changed, 621 insertions, 0 deletions
diff --git a/source3/locking/shmem_sysv.c b/source3/locking/shmem_sysv.c
new file mode 100644
index 0000000000..793e508c71
--- /dev/null
+++ b/source3/locking/shmem_sysv.c
@@ -0,0 +1,621 @@
+/*
+ Unix SMB/Netbios implementation.
+ Version 1.9.
+ Shared memory functions - SYSV IPC implementation
+ Copyright (C) Erik Devriendt 1996-1997
+
+ 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
+
+#define IPC_PERMS ((SHM_R | SHM_W) | (SHM_R>>3) | (SHM_R>>6))
+
+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 (struct ShmBlockDesc *)( 0 )
+#define EOList_Off (NULL_OFFSET)
+
+#define CellSize sizeof(struct ShmBlockDesc)
+
+/* HeaderSize aligned on 8 byte boundary */
+#define AlignedHeaderSize ((sizeof(struct ShmHeader)+7) & ~7)
+
+static struct ShmHeader *shm_header_p = (struct ShmHeader *)0;
+
+static BOOL shm_initialize_called = False;
+
+static int read_only;
+
+static BOOL sem_lock(int i)
+{
+ struct sembuf sb;
+ if (read_only) return True;
+
+ sb.sem_num = i;
+ sb.sem_op = -1;
+ sb.sem_flg = SEM_UNDO;
+
+ if (semop(sem_id, &sb, 1) != 0) {
+ DEBUG(0,("ERROR: IPC lock failed on semaphore %d\n", i));
+ return False;
+ }
+
+ return True;
+}
+
+static BOOL sem_unlock(int i)
+{
+ struct sembuf sb;
+ if (read_only) return True;
+
+ sb.sem_num = i;
+ sb.sem_op = 1;
+ sb.sem_flg = SEM_UNDO;
+
+ if (semop(sem_id, &sb, 1) != 0) {
+ DEBUG(0,("ERROR: IPC unlock failed on semaphore %d\n", i));
+ return False;
+ }
+
+ return True;
+}
+
+static BOOL global_lock(void)
+{
+ global_lock_count++;
+ if (global_lock_count == 1)
+ return sem_lock(0);
+ return True;
+}
+
+static BOOL global_unlock(void)
+{
+ global_lock_count--;
+ if (global_lock_count == 0)
+ return sem_unlock(0);
+ return True;
+}
+
+static void *shm_offset2addr(int offset)
+{
+ if (offset == NULL_OFFSET )
+ 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 NULL_OFFSET;
+
+ if (!shm_header_p)
+ return NULL_OFFSET;
+
+ 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 NULL_OFFSET;
+ }
+
+ global_lock();
+
+ if (!shm_header_p->consistent) {
+ DEBUG(0,("ERROR shm_alloc : shmem not consistent\n"));
+ global_unlock();
+ return NULL_OFFSET;
+ }
+
+ /* 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, no free space found\n",size));
+ global_unlock();
+ return (NULL_OFFSET);
+ }
+
+ /* 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) {
+ /* there is no use in making a new one, it will be too small anyway
+ * we will link out scanner
+ */
+ 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;
+ } else {
+ /* 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);
+
+ if (prev_p != scanner_p) {
+ prev_p->next = shm_addr2offset(new_p) ;
+ } else {
+ shm_header_p->first_free_off = shm_addr2offset(new_p);
+ }
+ shm_header_p->statistics.cells_free -= num_cells+1;
+ shm_header_p->statistics.cells_used += num_cells;
+ shm_header_p->statistics.cells_system += 1;
+ }
+
+ result_offset = shm_addr2offset( &(scanner_p[1]) );
+ scanner_p->next = SHM_NOT_FREE_OFF ;
+
+ /* end modification of shared mem */
+ shm_header_p->consistent = True;
+
+ DEBUG(6,("shm_alloc : request for %d bytes, allocated %d bytes at offset %d\n",size,scanner_p->size*CellSize,result_offset ));
+
+ global_unlock();
+ return result_offset;
+}
+
+
+
+/*
+ * 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 size )
+{
+ size *= sizeof(int);
+
+ global_lock();
+ shm_header_p->userdef_off = shm_alloc( size );
+
+ if(shm_header_p->userdef_off == NULL_OFFSET) {
+ 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 shm_validate_header : shmem size mismatch (old = %d, new = %d)\n",shm_header_p->total_size,size));
+ return False;
+ }
+
+ if(!shm_header_p->consistent) {
+ DEBUG(0,("ERROR shm_validate_header : 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 file of 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 = NULL_OFFSET;
+
+ 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;
+
+ shm_initialize_called = True;
+
+ return True;
+}
+
+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_close( void )
+{
+ return True;
+}
+
+
+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",
+ header_p->size*CellSize,offset));
+
+ 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 ); /* if neighbors then link them */
+
+ 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;
+}
+
+
+static int shm_get_userdef_off(void)
+{
+ if (!shm_header_p)
+ return NULL_OFFSET;
+ else
+ return shm_header_p->userdef_off;
+}
+
+/*******************************************************************
+ Lock a particular hash bucket entry.
+ ******************************************************************/
+static BOOL shm_lock_hash_entry(unsigned int entry)
+{
+ DEBUG(0,("hash lock %d\n", entry));
+ return sem_lock(entry+1);
+}
+
+/*******************************************************************
+ Unlock a particular hash bucket entry.
+ ******************************************************************/
+static BOOL shm_unlock_hash_entry(unsigned int entry)
+{
+ DEBUG(0,("hash unlock %d\n", entry));
+ return sem_unlock(entry+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;
+}
+
+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,
+};
+
+/*******************************************************************
+ open the shared memory
+ ******************************************************************/
+struct shmem_ops *sysv_shm_open(int size, int ronly)
+{
+ BOOL created_new = False;
+ BOOL other_processes;
+ struct shmid_ds shm_ds;
+ struct semid_ds sem_ds;
+ union semun su;
+ int i;
+
+ read_only = ronly;
+
+ shm_size = size;
+
+ DEBUG(4,("Trying sysv shmem open of size %d\n", size));
+
+ /* first the semaphore */
+ sem_id = semget(SEMAPHORE_KEY, 0, 0);
+ if (sem_id == -1) {
+ if (read_only) return NULL;
+
+ sem_id = semget(SEMAPHORE_KEY, lp_shmem_hash_size()+1,
+ IPC_CREAT | IPC_EXCL | IPC_PERMS);
+
+ if (sem_id == -1) {
+ DEBUG(0,("Can't create or use semaphore %s\n",
+ strerror(errno)));
+ }
+
+ if (sem_id != -1) {
+ su.val = 1;
+ for (i=0;i<lp_shmem_hash_size()+1;i++) {
+ if (semctl(sem_id, i, SETVAL, su) != 0) {
+ DEBUG(1,("Failed to init semaphore %d\n", i));
+ }
+ }
+ }
+ }
+ if (shm_id == -1) {
+ sem_id = semget(SEMAPHORE_KEY, 0, 0);
+ }
+ if (sem_id == -1) {
+ DEBUG(0,("Can't create or use semaphore %s\n",
+ strerror(errno)));
+ return NULL;
+ }
+
+ su.buf = &sem_ds;
+ if (semctl(sem_id, 0, IPC_STAT, su) != 0) {
+ DEBUG(0,("ERROR shm_open : can't IPC_STAT\n"));
+ }
+ hash_size = sem_ds.sem_nsems;
+ if (hash_size != lp_shmem_hash_size()+1) {
+ DEBUG(0,("WARNING: nsems=%d\n", hash_size));
+ }
+
+ if (!global_lock())
+ return NULL;
+
+ /* try to use an existing key */
+ shm_id = shmget(SHMEM_KEY, shm_size, 0);
+
+ /* if that failed then create one */
+ if (shm_id == -1) {
+ if (read_only) return NULL;
+ shm_id = shmget(SHMEM_KEY, shm_size, IPC_CREAT | IPC_EXCL);
+ created_new = (shm_id != -1);
+ }
+
+ if (shm_id == -1) {
+ DEBUG(0,("Can't create or use IPC area\n"));
+ global_unlock();
+ return NULL;
+ }
+
+
+ shm_header_p = (struct ShmHeader *)shmat(shm_id, 0,
+ read_only?SHM_RDONLY:0);
+ if ((int)shm_header_p == -1) {
+ DEBUG(0,("Can't attach to IPC area\n"));
+ 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 shm_open : can't IPC_STAT\n"));
+ }
+
+ /* set the permissions */
+ if (!read_only) {
+ shm_ds.shm_perm.mode = IPC_PERMS;
+ shmctl(shm_id, IPC_SET, &shm_ds);
+ }
+
+ 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(lp_shmem_hash_size());
+ DEBUG(1,("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
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