Change kernel-only open flag FNOSYMLINK to userland-visible O_NOFOLLOW;

adapated from FreeBSD.  Also change O_FSYNC to the more standard O_SYNC
and document it.  open(2) needs some real examples for proper usage,
to come later.

diff --git a/lib/libc/sys/open.2 b/lib/libc/sys/open.2
index 860340e..062ff00 100644 (file)
--- a/lib/libc/sys/open.2
+++ b/lib/libc/sys/open.2
@@ -1,4 +1,4 @@
-.\"    $OpenBSD: open.2,v 1.14 2000/04/10 19:36:02 deraadt Exp $
+.\"    $OpenBSD: open.2,v 1.15 2000/04/21 15:47:27 millert Exp $
 .\"    $NetBSD: open.2,v 1.8 1995/02/27 12:35:14 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993
@@ -77,8 +77,10 @@ O_APPEND     append on each write
 O_CREAT                create file if it does not exist
 O_TRUNC                truncate size to 0
 O_EXCL         error if create and file exists
+O_SYNC         perform syncronous I/O operations
 O_SHLOCK       atomically obtain a shared lock
 O_EXLOCK       atomically obtain an exclusive lock
+O_NOFOLLOW     if last path element is a symlink, don't follow it
 .Ed
 .Pp
 Opening a file with
@@ -97,9 +99,11 @@ exists,
 .Fn open
 returns an error.  This may be used to
 implement a simple exclusive access locking mechanism.
-If
+If either of
 .Dv O_EXCL
-is set and the last component of the pathname is
+or
+.Dv O_NOFOLLOW
+are set and the last component of the pathname is
 a symbolic link,
 .Fn open
 will fail even if the symbolic
@@ -115,6 +119,9 @@ carrier on a dialup line),
 .Fn open
 returns immediately.
 This flag also has the effect of making all subsequent I/O on the open file non-blocking.
+If the
+.Dv O_SYNC
+flag is set, all I/O operations on the file will be done syncronously.
 .Pp
 When opening a file, a lock with
 .Xr flock 2
@@ -275,6 +282,32 @@ is already locked.
 .Xr umask 2 ,
 .Xr write 2 ,
 .Xr getdtablesize 3
+.Sh STANDARDS
+The
+.Fn open
+function conforms to
+.St -ansiC ,
+.St -p1003.1-90
+and
+.St -xpg4.2 .
+.Pp
+.Dv POSIX
+specifies three different flavors for syncronous I/O:
+.Dv O_SYNC ,
+.Dv O_DSYNC
+and
+.Dv O_RSYNC .
+In
+.Ox ,
+these are all equivalent.
+.Pp
+The
+.Dv O_SHLOCK ,
+.Dv O_EXLOCK
+and
+.Dv O_NOFOLLOW
+flags are non-standard extensions and should not be used if portability
+is of concern.
 .Sh HISTORY
 An
 .Fn open

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 41c7bad..de148e6 100644 (file)
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_sig.c,v 1.36 2000/03/03 11:31:43 art Exp $       */
+/*     $OpenBSD: kern_sig.c,v 1.37 2000/04/21 15:47:27 millert Exp $   */
 /*     $NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $   */
 
 /*
@@ -1199,7 +1199,7 @@ coredump(p)
        sprintf(name, "%s.core", p->p_comm);
        NDINIT(&nd, LOOKUP, NOFOLLOW, UIO_SYSSPACE, name, p);
 
-       error = vn_open(&nd, O_CREAT | FWRITE | FNOSYMLINK, S_IRUSR | S_IWUSR);
+       error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR);
 
        if (error) {
                crfree(cred);

diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c
index e6ca0a7..e45b3d3 100644 (file)
--- a/sys/kern/vfs_vnops.c
+++ b/sys/kern/vfs_vnops.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vfs_vnops.c,v 1.24 2000/04/19 08:34:53 csapuntz Exp $ */
+/*     $OpenBSD: vfs_vnops.c,v 1.25 2000/04/21 15:47:28 millert Exp $  */
 /*     $NetBSD: vfs_vnops.c,v 1.20 1996/02/04 02:18:41 christos Exp $  */
 
 /*
@@ -95,8 +95,7 @@ vn_open(ndp, fmode, cmode)
        if (fmode & O_CREAT) {
                ndp->ni_cnd.cn_nameiop = CREATE;
                ndp->ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF;
-               if (((fmode & O_EXCL) == 0) &&
-                   ((fmode & FNOSYMLINK) == 0))
+               if ((fmode & O_EXCL) == 0 && (fmode & O_NOFOLLOW) == 0)
                        ndp->ni_cnd.cn_flags |= FOLLOW;
                if ((error = namei(ndp)) != 0)
                        return (error);
@@ -124,17 +123,11 @@ vn_open(ndp, fmode, cmode)
                                error = EEXIST;
                                goto bad;
                        }
-                       if ((ndp->ni_vp->v_type == VLNK) &&
-                           ((fmode & FNOSYMLINK) != 0)) {
-                               error = EFTYPE;
-                               goto bad;
-                       }
-
-                       fmode &= ~O_CREAT;
                }
        } else {
                ndp->ni_cnd.cn_nameiop = LOOKUP;
-               ndp->ni_cnd.cn_flags = FOLLOW | LOCKLEAF;
+               ndp->ni_cnd.cn_flags =
+                   ((fmode & O_NOFOLLOW) ? NOFOLLOW : FOLLOW) | LOCKLEAF;
                if ((error = namei(ndp)) != 0)
                        return (error);
                vp = ndp->ni_vp;
@@ -143,6 +136,10 @@ vn_open(ndp, fmode, cmode)
                error = EOPNOTSUPP;
                goto bad;
        }
+       if (vp->v_type == VLNK) {
+               error = EMLINK;
+               goto bad;
+       }
        if ((fmode & O_CREAT) == 0) {
                if (fmode & FREAD) {
                        if ((error = VOP_ACCESS(vp, VREAD, cred, p)) != 0)
@@ -326,7 +323,7 @@ vn_write(fp, poff, uio, cred)
                ioflag |= IO_APPEND;
        if (fp->f_flag & FNONBLOCK)
                ioflag |= IO_NDELAY;
-       if ((fp->f_flag & O_FSYNC) ||
+       if ((fp->f_flag & FFSYNC) ||
            (vp->v_mount && (vp->v_mount->mnt_flag & MNT_SYNCHRONOUS)))
                ioflag |= IO_SYNC;
        VOP_LEASE(vp, uio->uio_procp, cred, LEASE_WRITE);

diff --git a/sys/sys/fcntl.h b/sys/sys/fcntl.h
index 1acb5a2..99e1869 100644 (file)
--- a/sys/sys/fcntl.h
+++ b/sys/sys/fcntl.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: fcntl.h,v 1.5 1998/01/09 16:33:47 csapuntz Exp $      */
+/*     $OpenBSD: fcntl.h,v 1.6 2000/04/21 15:47:27 millert Exp $       */
 /*     $NetBSD: fcntl.h,v 1.8 1995/03/26 20:24:12 jtc Exp $    */
 
 /*-
@@ -85,8 +85,10 @@
 #define        O_SHLOCK        0x0010          /* open with shared file lock */
 #define        O_EXLOCK        0x0020          /* open with exclusive file lock */
 #define        O_ASYNC         0x0040          /* signal pgrp when data ready */
-#define        O_FSYNC         0x0080          /* synchronous writes */
+#define        O_FSYNC         O_SYNC          /* backwards compatibility */
+#define        O_NOFOLLOW      0x0100          /* if path is a symlink, don't follow */
 #endif
+#define        O_SYNC          0x0080          /* synchronous writes */
 #define        O_CREAT         0x0200          /* create if nonexistant */
 #define        O_TRUNC         0x0400          /* truncate to zero length */
 #define        O_EXCL          0x0800          /* error if already exists */
@@ -94,14 +96,16 @@
 #define        FMARK           0x1000          /* mark during gc() */
 #define        FDEFER          0x2000          /* defer for next gc pass */
 #define        FHASLOCK        0x4000          /* descriptor holds advisory lock */
-
-/* Note: The below is not a flag that can be used in the struct file. 
-   It's an option that can be passed to vn_open to make sure it doesn't
-   follow a symlink on the last lookup */
-#define FNOSYMLINK     0x10000          /* Don't follow symlink for last
-                                          component */
 #endif
 
+/*
+ * POSIX 1003.1 specifies a higher granularity for syncronous operations
+ * than we support.  Since synchronicity is all or nothing in OpenBSD
+ * we just define these to be the same as O_SYNC.
+ */
+#define        O_DSYNC         O_SYNC          /* synchronous data writes */
+#define        O_RSYNC         O_SYNC          /* synchronous reads */
+
 /* defined by POSIX 1003.1; BSD default, this bit is not required */
 #define        O_NOCTTY        0x8000          /* don't assign controlling terminal */
 
@@ -127,7 +131,7 @@
 #ifndef _POSIX_SOURCE
 #define        FAPPEND         O_APPEND        /* kernel/compat */
 #define        FASYNC          O_ASYNC         /* kernel/compat */
-#define        FFSYNC          O_FSYNC         /* kernel */
+#define        FFSYNC          O_SYNC          /* kernel */
 #define        FNONBLOCK       O_NONBLOCK      /* kernel */
 #define        FNDELAY         O_NONBLOCK      /* compat */
 #define        O_NDELAY        O_NONBLOCK      /* compat */