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-rw-r--r--db2/os/os_map.c440
1 files changed, 417 insertions, 23 deletions
diff --git a/db2/os/os_map.c b/db2/os/os_map.c
index b1553188dc..5f0fd790e6 100644
--- a/db2/os/os_map.c
+++ b/db2/os/os_map.c
@@ -1,47 +1,395 @@
/*-
* See the file LICENSE for redistribution information.
*
- * Copyright (c) 1996, 1997
+ * Copyright (c) 1996, 1997, 1998
* Sleepycat Software. All rights reserved.
*/
#include "config.h"
#ifndef lint
-static const char sccsid[] = "@(#)os_map.c 10.7 (Sleepycat) 10/25/97";
+static const char sccsid[] = "@(#)os_map.c 10.19 (Sleepycat) 5/3/98";
#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 "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((char *, REGINFO *));
+#endif
/*
- * __os_map --
- * Map in some shared memory backed by a file descriptor.
+ * __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(path, 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(path, 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;
+ }
+#else
+ COMPQUIET(infop, NULL);
+#endif
+#ifdef HAVE_MMAP
+ 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 __os_map __P((int, size_t, int, int, void **));
+ * PUBLIC: int __db_unmapfile __P((void *, size_t));
*/
int
-__os_map(fd, len, is_private, is_rdonly, addr)
- int fd, is_private, is_rdonly;
+__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;
- flags = is_private ? MAP_PRIVATE : MAP_SHARED;
+ 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
- flags |= MAP_HASSEMAPHORE;
+ if (!is_rdonly)
+ flags |= MAP_HASSEMAPHORE;
#endif
+
prot = PROT_READ | (is_rdonly ? 0 : PROT_WRITE);
-#ifndef MAP_FAILED /* XXX: Mmap(2) failure return. */
+ /* MAP_FAILED was not defined in early mmap implementations. */
+#ifndef MAP_FAILED
#define MAP_FAILED -1
#endif
if ((p =
@@ -51,21 +399,67 @@ __os_map(fd, len, is_private, is_rdonly, addr)
*addr = p;
return (0);
}
+#endif
+#ifdef HAVE_SHMGET
/*
- * __os_unmap --
- * Release the specified shared memory.
- *
- * PUBLIC: int __os_unmap __P((void *, size_t));
+ * __os_shmget --
+ * Call the shmget(2) family of functions.
*/
-int
-__os_unmap(addr, len)
- void *addr;
- size_t len;
+static int
+__os_shmget(path, infop)
+ REGINFO *infop;
+ char *path;
{
- /*
- * !!!
- * The argument len is always the same length as was mapped.
- */
- return (munmap(addr, len) ? errno : 0);
+ key_t key;
+ int shmflg;
+
+ if (F_ISSET(infop, REGION_CREATED)) {
+ /*
+ * The return key from ftok(3) is not guaranteed to be unique.
+ * The nice thing about the shmget(2) interface is that it
+ * allows you to name anonymous pieces of memory. The evil
+ * thing about it is that the name space is separate from the
+ * filesystem.
+ */
+#ifdef __hp3000s900
+ {char mpe_path[MAXPATHLEN];
+ /*
+ * MPE ftok() is broken as of 5.5pp4. If the file path does
+ * not start with '/' or '.', then ftok() tries to interpret
+ * the file path in MPE syntax instead of POSIX HFS syntax.
+ * The workaround is to prepend "./" to these paths. See HP
+ * SR 5003416081 for details.
+ */
+ if (*path != '/' && *path != '.') {
+ if (strlen(path) + strlen("./") + 1 > sizeof(mpe_path))
+ return (ENAMETOOLONG);
+ mpe_path[0] = '.';
+ mpe_path[1] = '/';
+ (void)strcpy(mpe_path + 2, path);
+ path = mpe_path;
+ }
+ }
+#endif
+ if ((key = ftok(path, 1)) == (key_t)-1)
+ return (errno);
+
+ shmflg = IPC_CREAT | 0600;
+ if ((infop->segid = shmget(key, infop->size, shmflg)) == -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