From c04030e16dbea2f7581f82cc6688695927f6ac5b Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Fri, 24 Feb 2006 13:04:21 -0800 Subject: [PATCH] [PATCH] flags parameter for linkat I'm currently at the POSIX meeting and one thing covered was the incompatibility of Linux's link() with the POSIX definition. The name. Linux does not follow symlinks, POSIX requires it does. Even if somebody thinks this is a good default behavior we cannot change this because it would break the ABI. But the fact remains that some application might want this behavior. We have one chance to help implementing this without breaking the behavior. For this we could use the new linkat interface which would need a new flags parameter. If the new parameter is AT_SYMLINK_FOLLOW the new behavior could be invoked. I do not want to introduce such a patch now. But we could add the parameter now, just don't use it. The patch below would do this. Can we get this late patch applied before the release more or less fixes the syscall API? Signed-off-by: Ulrich Drepper Signed-off-by: Ralf Baechle Cc: Heiko Carstens Cc: Martin Schwidefsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/mips/kernel/scall32-o32.S | 2 +- arch/s390/kernel/compat_wrapper.S | 1 + fs/namei.c | 8 ++++++-- include/linux/syscalls.h | 2 +- 4 files changed, 9 insertions(+), 4 deletions(-) diff --git a/arch/mips/kernel/scall32-o32.S b/arch/mips/kernel/scall32-o32.S index d83e033dbc87..2f2dc54b2e26 100644 --- a/arch/mips/kernel/scall32-o32.S +++ b/arch/mips/kernel/scall32-o32.S @@ -626,7 +626,7 @@ einval: li v0, -EINVAL sys sys_fstatat64 4 sys sys_unlinkat 3 sys sys_renameat 4 /* 4295 */ - sys sys_linkat 4 + sys sys_linkat 5 sys sys_symlinkat 3 sys sys_readlinkat 4 sys sys_fchmodat 3 diff --git a/arch/s390/kernel/compat_wrapper.S b/arch/s390/kernel/compat_wrapper.S index 615964cca15f..50e80138e7ad 100644 --- a/arch/s390/kernel/compat_wrapper.S +++ b/arch/s390/kernel/compat_wrapper.S @@ -1552,6 +1552,7 @@ sys_linkat_wrapper: llgtr %r3,%r3 # const char * lgfr %r4,%r4 # int llgtr %r5,%r5 # const char * + lgfr %r6,%r6 # int jg sys_linkat .globl sys_symlinkat_wrapper diff --git a/fs/namei.c b/fs/namei.c index e28de846c591..557dcf395ca1 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2224,13 +2224,17 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de * and other special files. --ADM */ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, - int newdfd, const char __user *newname) + int newdfd, const char __user *newname, + int flags) { struct dentry *new_dentry; struct nameidata nd, old_nd; int error; char * to; + if (flags != 0) + return -EINVAL; + to = getname(newname); if (IS_ERR(to)) return PTR_ERR(to); @@ -2263,7 +2267,7 @@ asmlinkage long sys_linkat(int olddfd, const char __user *oldname, asmlinkage long sys_link(const char __user *oldname, const char __user *newname) { - return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname); + return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); } /* diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index d73501ba7e44..b9ea44ac0ddb 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -543,7 +543,7 @@ asmlinkage long sys_unlinkat(int dfd, const char __user * pathname, int flag); asmlinkage long sys_symlinkat(const char __user * oldname, int newdfd, const char __user * newname); asmlinkage long sys_linkat(int olddfd, const char __user *oldname, - int newdfd, const char __user *newname); + int newdfd, const char __user *newname, int flags); asmlinkage long sys_renameat(int olddfd, const char __user * oldname, int newdfd, const char __user * newname); asmlinkage long sys_futimesat(int dfd, char __user *filename,