recognize different byte orders automatically; m_lorder no longer used

SCCS-vsn: lib/libc/db/btree/bt_open.c 5.27

diff --git a/usr/src/lib/libc/db/btree/bt_open.c b/usr/src/lib/libc/db/btree/bt_open.c
index 73ad71a..78820a3 100644 (file)
--- a/usr/src/lib/libc/db/btree/bt_open.c
+++ b/usr/src/lib/libc/db/btree/bt_open.c
@@ -9,7 +9,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)

-static char sccsid[] = "@(#)bt_open.c  5.26 (Berkeley) %G%";
+static char sccsid[] = "@(#)bt_open.c  5.27 (Berkeley) %G%";

 #endif /* LIBC_SCCS and not lint */
 
 /*
 #endif /* LIBC_SCCS and not lint */
 
 /*


@@ -36,6 +36,7 @@ static char sccsid[] = "@(#)bt_open.c 5.26 (Berkeley) %G%";
 #include <db.h>
 #include "btree.h"
 
 #include <db.h>
 #include "btree.h"
 

+static int byteorder __P((void));

 static int nroot __P((BTREE *));
 static int tmp __P((void));
 
 static int nroot __P((BTREE *));
 static int tmp __P((void));
 


@@ -67,7 +68,7 @@ __bt_open(fname, flags, mode, openinfo)
        DB *dbp;
        pgno_t ncache;
        struct stat sb;
        DB *dbp;
        pgno_t ncache;
        struct stat sb;

-       int nr;
+       int machine_lorder, nr;

 
        t = NULL;
 
 
        t = NULL;
 


@@ -78,6 +79,7 @@ __bt_open(fname, flags, mode, openinfo)
         * file is opened.  Also, the file's page size can cause the cachesize
         * to change.
         */
         * file is opened.  Also, the file's page size can cause the cachesize
         * to change.
         */

+       machine_lorder = byteorder();

        if (openinfo) {
                b = *openinfo;
 
        if (openinfo) {
                b = *openinfo;
 


@@ -110,19 +112,21 @@ __bt_open(fname, flags, mode, openinfo)
                }
 
                if (b.lorder == 0)
                }
 
                if (b.lorder == 0)

-                       b.lorder = BYTE_ORDER;
-               else if (b.lorder != BIG_ENDIAN && b.lorder != LITTLE_ENDIAN)
-                       goto einval;
+                       b.lorder = machine_lorder;

        } else {
                b.compare = __bt_defcmp;
                b.cachesize = 0;
                b.flags = 0;
        } else {
                b.compare = __bt_defcmp;
                b.cachesize = 0;
                b.flags = 0;

-               b.lorder = BYTE_ORDER;
+               b.lorder = machine_lorder;

                b.minkeypage = DEFMINKEYPAGE;
                b.prefix = __bt_defpfx;
                b.psize = 0;
        }
 
                b.minkeypage = DEFMINKEYPAGE;
                b.prefix = __bt_defpfx;
                b.psize = 0;
        }
 

+       /* Check for the ubiquitous PDP-11. */
+       if (b.lorder != BIG_ENDIAN && b.lorder != LITTLE_ENDIAN)
+               goto einval;
+

        /* Allocate and initialize DB and BTREE structures. */
        if ((t = malloc(sizeof(BTREE))) == NULL)
                goto err;
        /* Allocate and initialize DB and BTREE structures. */
        if ((t = malloc(sizeof(BTREE))) == NULL)
                goto err;


@@ -135,10 +139,13 @@ __bt_open(fname, flags, mode, openinfo)
        t->bt_sp = t->bt_maxstack = 0;
        t->bt_kbuf = t->bt_dbuf = NULL;
        t->bt_kbufsz = t->bt_dbufsz = 0;
        t->bt_sp = t->bt_maxstack = 0;
        t->bt_kbuf = t->bt_dbuf = NULL;
        t->bt_kbufsz = t->bt_dbufsz = 0;

+       t->bt_lorder = b.lorder;

        t->bt_order = NOT;
        t->bt_cmp = b.compare;
        t->bt_pfx = b.prefix;
        t->bt_flags = 0;
        t->bt_order = NOT;
        t->bt_cmp = b.compare;
        t->bt_pfx = b.prefix;
        t->bt_flags = 0;

+       if (t->bt_lorder != machine_lorder)
+               SET(t, BTF_NEEDSWAP);

 
        dbp->type = DB_BTREE;
        dbp->internal = t;
 
        dbp->type = DB_BTREE;
        dbp->internal = t;


@@ -192,14 +199,15 @@ __bt_open(fname, flags, mode, openinfo)
                /*
                 * Read in the meta-data.  This can change the notion of what
                 * the lorder, page size and flags are, and, when the page size
                /*
                 * Read in the meta-data.  This can change the notion of what
                 * the lorder, page size and flags are, and, when the page size

-                * changes the cachesize value can change as well.
-                *
-                * Lorder is always stored in host-independent format.
+                * changes, the cachesize value can change too.  If the user
+                * specified the wrong byte order for an existing database, we
+                * don't bother to return an error, we just clear the NEEDSWAP
+                * bit.

                 */
                 */

-               m.m_lorder = ntohl(m.m_lorder);
-               if (m.m_lorder != BIG_ENDIAN && m.m_lorder != LITTLE_ENDIAN)
-                       goto eftype;
-               if (m.m_lorder != BYTE_ORDER) {
+               if (m.m_magic == BTREEMAGIC)
+                       CLR(t, BTF_NEEDSWAP);
+               else {
+                       SET(t, BTF_NEEDSWAP);

                        BLSWAP(m.m_magic);
                        BLSWAP(m.m_version);
                        BLSWAP(m.m_psize);
                        BLSWAP(m.m_magic);
                        BLSWAP(m.m_version);
                        BLSWAP(m.m_psize);


@@ -217,7 +225,6 @@ __bt_open(fname, flags, mode, openinfo)
                b.psize = m.m_psize;
                t->bt_flags |= m.m_flags;
                t->bt_free = m.m_free;
                b.psize = m.m_psize;
                t->bt_flags |= m.m_flags;
                t->bt_free = m.m_free;

-               t->bt_lorder = m.m_lorder;

                t->bt_nrecs = m.m_nrecs;
        } else {
                /*
                t->bt_nrecs = m.m_nrecs;
        } else {
                /*


@@ -231,10 +238,12 @@ __bt_open(fname, flags, mode, openinfo)
                        if (b.psize > MAX_PAGE_OFFSET)
                                b.psize = MAX_PAGE_OFFSET;
                }
                        if (b.psize > MAX_PAGE_OFFSET)
                                b.psize = MAX_PAGE_OFFSET;
                }

+
+               /* Set flag if duplicates permitted. */

                if (!(b.flags & R_DUP))
                        SET(t, BTF_NODUPS);
                if (!(b.flags & R_DUP))
                        SET(t, BTF_NODUPS);

+

                t->bt_free = P_INVALID;
                t->bt_free = P_INVALID;

-               t->bt_lorder = b.lorder;

                t->bt_nrecs = 0;
                SET(t, BTF_METADIRTY);
        }
                t->bt_nrecs = 0;
                SET(t, BTF_METADIRTY);
        }


@@ -357,3 +366,21 @@ tmp()
        (void)sigprocmask(SIG_SETMASK, &oset, NULL);
        return(fd);
 }
        (void)sigprocmask(SIG_SETMASK, &oset, NULL);
        return(fd);
 }

+
+static int
+byteorder()
+{
+       u_long x;                       /* XXX: 32-bit assumption. */
+       char *p;
+
+       x = 0x01020304;
+       p = (u_char *)&x;
+       switch (*p) {
+       case 1:
+               return (BIG_ENDIAN);
+       case 4:
+               return (LITTLE_ENDIAN);
+       default:
+               return (0);
+       }
+}