ignore bogus (large) return values from read

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

diff --git a/usr/src/sys/kern/vfs_vnops.c b/usr/src/sys/kern/vfs_vnops.c
index 615320d..0e4a8d0 100644 (file)
--- a/usr/src/sys/kern/vfs_vnops.c
+++ b/usr/src/sys/kern/vfs_vnops.c
@@ -1,4 +1,4 @@
-/*     vfs_vnops.c     4.33    83/02/16        */
+/*     vfs_vnops.c     4.33    83/02/20        */

 
 #include "../machine/reg.h"
 
 
 #include "../machine/reg.h"
 


@@ -65,6 +65,12 @@ access(ip, mode)
 
        m = mode;
        if (m == IWRITE) {
 
        m = mode;
        if (m == IWRITE) {

+               /*
+                * Disallow write attempts on read-only
+                * file systems; unless the file is a block
+                * or character device resident on the
+                * file system.
+                */

                if (ip->i_fs->fs_ronly != 0) {
                        if ((ip->i_mode & IFMT) != IFCHR &&
                            (ip->i_mode & IFMT) != IFBLK) {
                if (ip->i_fs->fs_ronly != 0) {
                        if ((ip->i_mode & IFMT) != IFCHR &&
                            (ip->i_mode & IFMT) != IFBLK) {


@@ -72,17 +78,35 @@ access(ip, mode)
                                return (1);
                        }
                }
                                return (1);
                        }
                }

-               if (ip->i_flag&ITEXT)           /* try to free text */
+               /*
+                * If there's shared text associated with
+                * the inode, try to free it up once.  If
+                * we fail, we can't allow writing.
+                */
+               if (ip->i_flag&ITEXT)

                        xrele(ip);
                if (ip->i_flag & ITEXT) {
                        u.u_error = ETXTBSY;
                        return (1);
                }
        }
                        xrele(ip);
                if (ip->i_flag & ITEXT) {
                        u.u_error = ETXTBSY;
                        return (1);
                }
        }

+       /*
+        * If you're the super-user,
+        * you always get access.
+        */

        if (u.u_uid == 0)
                return (0);
        if (u.u_uid == 0)
                return (0);

+       /*
+        * Access check is based on only
+        * one of owner, group, public.
+        * If not owner, then check group.
+        * If not a member of the group, then
+        * check public access.
+        */

        if (u.u_uid != ip->i_uid) {
                m >>= 3;
        if (u.u_uid != ip->i_uid) {
                m >>= 3;

+               if (u.u_gid == ip->i_gid)
+                       goto found;

                for (gp = u.u_groups; gp < &u.u_groups[NGROUPS]; gp++)
                        if (ip->i_gid == *gp)
                                goto found;
                for (gp = u.u_groups; gp < &u.u_groups[NGROUPS]; gp++)
                        if (ip->i_gid == *gp)
                                goto found;