diff options
Diffstat (limited to 'db2/os/os_map.c')
| -rw-r--r-- | db2/os/os_map.c | 447 |
1 files changed, 0 insertions, 447 deletions
diff --git a/db2/os/os_map.c b/db2/os/os_map.c deleted file mode 100644 index 5664a2edec..0000000000 --- a/db2/os/os_map.c +++ /dev/null @@ -1,447 +0,0 @@ -/*- - * See the file LICENSE for redistribution information. - * - * Copyright (c) 1996, 1997, 1998 - * Sleepycat Software. All rights reserved. - */ - -#include "config.h" - -#ifndef lint -static const char sccsid[] = "@(#)os_map.c 10.24 (Sleepycat) 10/12/98"; -#endif /* not lint */ - -#ifndef NO_SYSTEM_INCLUDES -#include <sys/types.h> -#ifdef HAVE_MMAP -#include <sys/mman.h> -#endif - -#ifdef HAVE_SHMGET -#include <sys/ipc.h> -#include <sys/shm.h> -#endif - -#include <errno.h> -#include <string.h> -#endif - -#include "db_int.h" -#include "os_jump.h" -#include "common_ext.h" - -#ifdef HAVE_MMAP -static int __os_map __P((char *, int, size_t, int, int, int, void **)); -#endif -#ifdef HAVE_SHMGET -static int __os_shmget __P((REGINFO *)); -#endif - -/* - * __db_mapanon_ok -- - * Return if this OS can support anonymous memory regions. - * - * PUBLIC: int __db_mapanon_ok __P((int)); - */ -int -__db_mapanon_ok(need_names) - int need_names; -{ - int ret; - - ret = EINVAL; - - /* - * If we don't have spinlocks, we have to have a file descriptor - * for fcntl(2) locking, which implies using mmap(2) to map in a - * regular file. Theoretically, we could probably find ways to - * get a file descriptor to lock other types of shared regions, - * but I don't see any reason to do so. - * - * If need_names is set, the application wants to share anonymous - * memory among multiple processes, so we have to have a way to - * name it. This requires shmget(2), on UNIX systems. - */ -#ifdef HAVE_SPINLOCKS -#ifdef HAVE_SHMGET - ret = 0; -#endif -#ifdef HAVE_MMAP -#ifdef MAP_ANON - if (!need_names) - ret = 0; -#endif -#ifdef MAP_ANONYMOUS - if (!need_names) - ret = 0; -#endif -#else - COMPQUIET(need_names, 0); -#endif /* HAVE_MMAP */ -#endif /* HAVE_SPINLOCKS */ - - return (ret); -} - -/* - * __db_mapinit -- - * Return if shared regions need to be initialized. - * - * PUBLIC: int __db_mapinit __P((void)); - */ -int -__db_mapinit() -{ - /* - * Historically, some systems required that all of the bytes of the - * region be written before it could be mmapped and accessed randomly. - * We have the option of setting REGION_INIT_NEEDED at configuration - * time if we're running on one of those systems. - */ -#ifdef REGION_INIT_NEEDED - return (1); -#else - return (0); -#endif -} - -/* - * __db_mapregion -- - * Attach to a shared memory region. - * - * PUBLIC: int __db_mapregion __P((char *, REGINFO *)); - */ -int -__db_mapregion(path, infop) - char *path; - REGINFO *infop; -{ - int called, ret; - - called = 0; - ret = EINVAL; - - /* If the user replaces the map call, call through their interface. */ - if (__db_jump.j_map != NULL) { - F_SET(infop, REGION_HOLDINGSYS); - return (__db_jump.j_map(path, infop->fd, infop->size, - 1, F_ISSET(infop, REGION_ANONYMOUS), 0, &infop->addr)); - } - - if (F_ISSET(infop, REGION_ANONYMOUS)) { - /* - * !!! - * If we're creating anonymous regions: - * - * If it's private, we use mmap(2). The problem with using - * shmget(2) is that we may be creating a region of which the - * application isn't aware, and if the application crashes - * we'll have no way to remove the system resources for the - * region. - * - * If it's not private, we use the shmget(2) interface if it's - * available, because it allows us to name anonymous memory. - * If shmget(2) isn't available, use the mmap(2) calls. - * - * In the case of anonymous memory, using mmap(2) means the - * memory isn't named and only the single process and its - * threads can access the region. - */ -#ifdef HAVE_MMAP -#ifdef MAP_ANON -#define HAVE_MMAP_ANONYMOUS 1 -#else -#ifdef MAP_ANONYMOUS -#define HAVE_MMAP_ANONYMOUS 1 -#endif -#endif -#endif -#ifdef HAVE_MMAP_ANONYMOUS - if (!called && F_ISSET(infop, REGION_PRIVATE)) { - called = 1; - ret = __os_map(path, - infop->fd, infop->size, 1, 1, 0, &infop->addr); - } -#endif -#ifdef HAVE_SHMGET - if (!called) { - called = 1; - ret = __os_shmget(infop); - } -#endif -#ifdef HAVE_MMAP - /* - * If we're trying to join an unnamed anonymous region, fail -- - * that's not possible. - */ - if (!called) { - called = 1; - - if (!F_ISSET(infop, REGION_CREATED)) { - __db_err(infop->dbenv, - "cannot join region in unnamed anonymous memory"); - return (EINVAL); - } - - ret = __os_map(path, - infop->fd, infop->size, 1, 1, 0, &infop->addr); - } -#endif - } else { - /* - * !!! - * If we're creating normal regions, we use the mmap(2) - * interface if it's available because it's POSIX 1003.1 - * standard and we trust it more than we do shmget(2). - */ -#ifdef HAVE_MMAP - if (!called) { - called = 1; - - /* Mmap(2) regions that aren't anonymous can grow. */ - F_SET(infop, REGION_CANGROW); - - ret = __os_map(path, - infop->fd, infop->size, 1, 0, 0, &infop->addr); - } -#endif -#ifdef HAVE_SHMGET - if (!called) { - called = 1; - ret = __os_shmget(infop); - } -#endif - } - return (ret); -} - -/* - * __db_unmapregion -- - * Detach from the shared memory region. - * - * PUBLIC: int __db_unmapregion __P((REGINFO *)); - */ -int -__db_unmapregion(infop) - REGINFO *infop; -{ - int called, ret; - - called = 0; - ret = EINVAL; - - if (__db_jump.j_unmap != NULL) - return (__db_jump.j_unmap(infop->addr, infop->size)); - -#ifdef HAVE_SHMGET - if (infop->segid != INVALID_SEGID) { - called = 1; - ret = shmdt(infop->addr) ? errno : 0; - } -#endif -#ifdef HAVE_MMAP - if (!called) { - called = 1; - ret = munmap(infop->addr, infop->size) ? errno : 0; - } -#endif - return (ret); -} - -/* - * __db_unlinkregion -- - * Remove the shared memory region. - * - * PUBLIC: int __db_unlinkregion __P((char *, REGINFO *)); - */ -int -__db_unlinkregion(name, infop) - char *name; - REGINFO *infop; -{ - int called, ret; - - called = 0; - ret = EINVAL; - - if (__db_jump.j_runlink != NULL) - return (__db_jump.j_runlink(name)); - -#ifdef HAVE_SHMGET - if (infop->segid != INVALID_SEGID) { - called = 1; - ret = shmctl(infop->segid, IPC_RMID, NULL) ? errno : 0; - } -#endif -#ifdef HAVE_MMAP - COMPQUIET(infop, NULL); - if (!called) { - called = 1; - ret = 0; - } -#endif - return (ret); -} - -/* - * __db_mapfile -- - * Map in a shared memory file. - * - * PUBLIC: int __db_mapfile __P((char *, int, size_t, int, void **)); - */ -int -__db_mapfile(path, fd, len, is_rdonly, addr) - char *path; - int fd, is_rdonly; - size_t len; - void **addr; -{ - if (__db_jump.j_map != NULL) - return (__db_jump.j_map(path, fd, len, 0, 0, is_rdonly, addr)); - -#ifdef HAVE_MMAP - return (__os_map(path, fd, len, 0, 0, is_rdonly, addr)); -#else - return (EINVAL); -#endif -} - -/* - * __db_unmapfile -- - * Unmap the shared memory file. - * - * PUBLIC: int __db_unmapfile __P((void *, size_t)); - */ -int -__db_unmapfile(addr, len) - void *addr; - size_t len; -{ - if (__db_jump.j_unmap != NULL) - return (__db_jump.j_unmap(addr, len)); - -#ifdef HAVE_MMAP - return (munmap(addr, len) ? errno : 0); -#else - return (EINVAL); -#endif -} - -#ifdef HAVE_MMAP -/* - * __os_map -- - * Call the mmap(2) function. - */ -static int -__os_map(path, fd, len, is_region, is_anonymous, is_rdonly, addr) - char *path; - int fd, is_region, is_anonymous, is_rdonly; - size_t len; - void **addr; -{ - void *p; - int flags, prot; - - COMPQUIET(path, NULL); - - /* - * If it's read-only, it's private, and if it's not, it's shared. - * Don't bother with an additional parameter. - */ - flags = is_rdonly ? MAP_PRIVATE : MAP_SHARED; - - if (is_region && is_anonymous) { - /* - * BSD derived systems use MAP_ANON; Digital Unix and HP/UX - * use MAP_ANONYMOUS. - */ -#ifdef MAP_ANON - flags |= MAP_ANON; -#endif -#ifdef MAP_ANONYMOUS - flags |= MAP_ANONYMOUS; -#endif - fd = -1; - } -#ifdef MAP_FILE - if (!is_region || !is_anonymous) { - /* - * Historically, MAP_FILE was required for mapping regular - * files, even though it was the default. Some systems have - * it, some don't, some that have it set it to 0. - */ - flags |= MAP_FILE; - } -#endif - - /* - * I know of no systems that implement the flag to tell the system - * that the region contains semaphores, but it's not an unreasonable - * thing to do, and has been part of the design since forever. I - * don't think anyone will object, but don't set it for read-only - * files, it doesn't make sense. - */ -#ifdef MAP_HASSEMAPHORE - if (!is_rdonly) - flags |= MAP_HASSEMAPHORE; -#endif - - prot = PROT_READ | (is_rdonly ? 0 : PROT_WRITE); - -/* - * XXX - * Work around a bug in the VMS V7.1 mmap() implementation. To map a file - * into memory on VMS it needs to be opened in a certain way, originally. - * To get the file opened in that certain way, the VMS mmap() closes the - * file and re-opens it. When it does this, it doesn't flush any caches - * out to disk before closing. The problem this causes us is that when the - * memory cache doesn't get written out, the file isn't big enough to match - * the memory chunk and the mmap() call fails. This call to fsync() fixes - * the problem. DEC thinks this isn't a bug because of language in XPG5 - * discussing user responsibility for on-disk and in-memory synchronization. - */ -#ifdef VMS - if (__os_fsync(fd) == -1) - return(errno); -#endif - - /* MAP_FAILED was not defined in early mmap implementations. */ -#ifndef MAP_FAILED -#define MAP_FAILED -1 -#endif - if ((p = - mmap(NULL, len, prot, flags, fd, (off_t)0)) == (void *)MAP_FAILED) - return (errno); - - *addr = p; - return (0); -} -#endif - -#ifdef HAVE_SHMGET -/* - * __os_shmget -- - * Call the shmget(2) family of functions. - */ -static int -__os_shmget(infop) - REGINFO *infop; -{ - if (F_ISSET(infop, REGION_CREATED) && - (infop->segid = shmget(0, infop->size, IPC_PRIVATE | 0600)) == -1) - return (errno); - - if ((infop->addr = shmat(infop->segid, NULL, 0)) == (void *)-1) { - /* - * If we're trying to join the region and failing, assume - * that there was a reboot and the region no longer exists. - */ - if (!F_ISSET(infop, REGION_CREATED)) - errno = EAGAIN; - return (errno); - } - - F_SET(infop, REGION_HOLDINGSYS); - return (0); -} -#endif |