move most of the directory consistency checks out of main loop.

[unix-history] / usr / src / sys / kern / vfs_lookup.c

diff --git a/usr/src/sys/kern/vfs_lookup.c b/usr/src/sys/kern/vfs_lookup.c
index b2cd4c9..c04dcdf 100644 (file)
--- a/usr/src/sys/kern/vfs_lookup.c
+++ b/usr/src/sys/kern/vfs_lookup.c
@@ -1,4 +1,4 @@
-/*     vfs_lookup.c    6.7     84/06/27        */
+/*     vfs_lookup.c    6.8     84/07/02        */

 
 #include "../h/param.h"
 #include "../h/systm.h"
 
 #include "../h/param.h"
 #include "../h/systm.h"


@@ -390,8 +390,7 @@ searchloop:
 
                /*
                 * If still looking for a slot, and at a DIRBLKSIZE
 
                /*
                 * If still looking for a slot, and at a DIRBLKSIZE

-                * boundary, have to start looking for free space
-                * again.
+                * boundary, have to start looking for free space again.

                 */
                if (slotstatus == NONE &&
                    (entryoffsetinblock&(DIRBLKSIZ-1)) == 0) {
                 */
                if (slotstatus == NONE &&
                    (entryoffsetinblock&(DIRBLKSIZ-1)) == 0) {


@@ -400,23 +399,17 @@ searchloop:
                }
 
                /*
                }
 
                /*

-                * Get pointer to next entry, and do consistency checking:
-                *      record length must be multiple of 4
-                *      record length must not be zero
-                *      entry must fit in rest of this DIRBLKSIZ block
-                *      record must be large enough to contain name
-                * When dirchk is set we also check:
-                *      name is not longer than MAXNAMLEN
-                *      name must be as long as advertised, and null terminated
-                * Checking last two conditions is done only when dirchk is
-                * set, to save time.
+                * Get pointer to next entry.
+                * Full validation checks are slow, so we only check
+                * enough to insure forward progress through the
+                * directory. Complete checks can be run by patching
+                * "dirchk" to be true.

                 */
                ep = (struct direct *)(bp->b_un.b_addr + entryoffsetinblock);
                 */
                ep = (struct direct *)(bp->b_un.b_addr + entryoffsetinblock);

-               i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));
-               if ((ep->d_reclen & 0x3) || ep->d_reclen == 0 ||
-                   ep->d_reclen > i || DIRSIZ(ep) > ep->d_reclen ||
-                   dirchk && (ep->d_namlen > MAXNAMLEN || dirbadname(ep))) {
+               if (ep->d_reclen <= 0 ||
+                   dirchk && dirbadentry(ep, entryoffsetinblock)) {

                        dirbad(dp, "mangled entry");
                        dirbad(dp, "mangled entry");

+                       i = DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1));

                        u.u_offset += i;
                        entryoffsetinblock += i;
                        continue;
                        u.u_offset += i;
                        entryoffsetinblock += i;
                        continue;


@@ -813,11 +806,25 @@ dirbad(ip, how)
            ip->i_fs->fs_fsmnt, ip->i_number, u.u_offset, how);
 }
 
            ip->i_fs->fs_fsmnt, ip->i_number, u.u_offset, how);
 }
 

-dirbadname(ep)
+/*
+ * Do consistency checking on a directory entry:
+ *     record length must be multiple of 4
+ *     record length must not be non-negative
+ *     entry must fit in rest of its DIRBLKSIZ block
+ *     record must be large enough to contain entry
+ *     name is not longer than MAXNAMLEN
+ *     name must be as long as advertised, and null terminated
+ */
+dirbadentry(ep, entryoffsetinblock)

        register struct direct *ep;
        register struct direct *ep;

+       int entryoffsetinblock;

 {
        register int i;
 
 {
        register int i;
 

+       if ((ep->d_reclen & 0x3) != 0 || ep->d_reclen <= 0 ||
+           ep->d_reclen > DIRBLKSIZ - (entryoffsetinblock & (DIRBLKSIZ - 1)) ||
+           ep->d_reclen < DIRSIZ(ep) || ep->d_namlen > MAXNAMLEN)
+               return (1);

        for (i = 0; i < ep->d_namlen; i++)
                if (ep->d_name[i] == 0)
                        return (1);
        for (i = 0; i < ep->d_namlen; i++)
                if (ep->d_name[i] == 0)
                        return (1);