From 51916406af05060bf8aa079a6c6938537d3b1599 Mon Sep 17 00:00:00 2001 From: millert Date: Fri, 21 Apr 2000 15:47:27 +0000 Subject: [PATCH] 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. --- lib/libc/sys/open.2 | 39 ++++++++++++++++++++++++++++++++++++--- sys/kern/kern_sig.c | 4 ++-- sys/kern/vfs_vnops.c | 21 +++++++++------------ sys/sys/fcntl.h | 22 +++++++++++++--------- 4 files changed, 60 insertions(+), 26 deletions(-) diff --git a/lib/libc/sys/open.2 b/lib/libc/sys/open.2 index 860340e6b63..062ff002537 100644 --- 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 41c7badf86f..de148e69821 100644 --- 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 e6ca0a79df3..e45b3d30c30 100644 --- 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 1acb5a2bb8e..99e18695481 100644 --- 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 */ -- 2.20.1