don't overflow doing long writes on ptc (from thomas@utah-cs)

[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 90f2cdf..56202c0 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    4.39    83/05/28        */
+/*     vfs_lookup.c    6.2     83/09/09        */

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


@@ -160,7 +160,7 @@ dirloop2:
         */
        if (u.u_dent.d_name[0] == 0) {
                if (flag || lockparent) {
         */
        if (u.u_dent.d_name[0] == 0) {
                if (flag || lockparent) {

-                       u.u_error = ENOENT;
+                       u.u_error = EISDIR;

                        goto bad;
                }
                brelse(nbp);
                        goto bad;
                }
                brelse(nbp);


@@ -743,28 +743,44 @@ blkatoff(ip, offset, res)
 /*
  * Check if a directory is empty or not.
  * Inode supplied must be locked.
 /*
  * Check if a directory is empty or not.
  * Inode supplied must be locked.

+ *
+ * Using a struct dirtemplate here is not precisely
+ * what we want, but better than using a struct direct.
+ *
+ * NB: does not handle corrupted directories.

  */
 dirempty(ip)
        register struct inode *ip;
 {
        register off_t off;
  */
 dirempty(ip)
        register struct inode *ip;
 {
        register off_t off;

-       struct direct dbuf;
-       register struct direct *dp = &dbuf;
+       struct dirtemplate dbuf;
+       register struct direct *dp = (struct direct *)&dbuf;

        int error, count;
        int error, count;

+#define        MINDIRSIZ (sizeof (struct dirtemplate) / 2)

 
        for (off = 0; off < ip->i_size; off += dp->d_reclen) {
 
        for (off = 0; off < ip->i_size; off += dp->d_reclen) {

-               error = rdwri(UIO_READ, ip, (caddr_t)dp,
-                       sizeof (struct direct), off, 1, &count);
-               count = sizeof (struct direct) - count;
-#define        MINDIRSIZ (sizeof (struct direct) - (MAXNAMLEN + 1))
-               if (error || count < MINDIRSIZ || count < DIRSIZ(dp))
+               error = rdwri(UIO_READ, ip, (caddr_t)dp, MINDIRSIZ,
+                   off, 1, &count);
+               /*
+                * Since we read MINDIRSIZ, residual must
+                * be 0 unless we're at end of file.
+                */
+               if (error || count != 0)

                        return (0);
                        return (0);

+               /* skip empty entries */

                if (dp->d_ino == 0)
                        continue;
                if (dp->d_ino == 0)
                        continue;

+               /* accept only "." and ".." */
+               if (dp->d_namlen > 2)
+                       return (0);

                if (dp->d_name[0] != '.')
                        return (0);
                if (dp->d_name[0] != '.')
                        return (0);

-               if (dp->d_namlen == 1 ||
-                   (dp->d_namlen == 2 && dp->d_name[1] == '.'))
+               /*
+                * At this point d_namlen must be 1 or 2.
+                * 1 implies ".", 2 implies ".." if second
+                * char is also "."
+                */
+               if (dp->d_namlen == 1 || dp->d_name[1] == '.')

                        continue;
                return (0);
        }
                        continue;
                return (0);
        }