From: Nicolas Thery <nthery@gmail.com>
Date: Sun, 9 Aug 2009 17:33:23 +0000 (+0200)
Subject: add fchownat(2) system call
X-Git-Tag: v2.4.0~292^2~1
X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff_plain/32013176c8992dafb4587c2a186d4aca1227756a

add fchownat(2) system call

Add also libc_r wrapper and man page.
---

diff --git a/include/unistd.h b/include/unistd.h
index 83139db302..1735b98599 100644
--- a/include/unistd.h
+++ b/include/unistd.h
@@ -318,6 +318,7 @@ int	 access(const char *, int);
 unsigned int	 alarm(unsigned int);
 int	 chdir(const char *);
 int	 chown(const char *, uid_t, gid_t);
+int	 fchownat(int, const char *, uid_t, gid_t, int);
 int	 close(int);
 int	 dup(int);
 int	 dup2(int, int);
diff --git a/lib/libc/sys/Makefile.inc b/lib/libc/sys/Makefile.inc
index dd847f8341..01f76999ed 100644
--- a/lib/libc/sys/Makefile.inc
+++ b/lib/libc/sys/Makefile.inc
@@ -103,7 +103,7 @@ MLINKS+=caps_sys_get.2 caps_sys_wait.2
 MLINKS+=chdir.2 fchdir.2
 MLINKS+=chflags.2 fchflags.2 chflags.2 lchflags.2
 MLINKS+=chmod.2 fchmod.2 chmod.2 lchmod.2 chmod.2 fchmodat.2
-MLINKS+=chown.2 fchown.2 chown.2 lchown.2
+MLINKS+=chown.2 fchown.2 chown.2 lchown.2 chown.2 fchownat.2
 MLINKS+=clock_gettime.2 clock_getres.2 clock_gettime.2 clock_settime.2
 MLINKS+=dup.2 dup2.2
 MLINKS+=fhopen.2 fhstat.2 fhopen.2 fhstatfs.2 fhopen.2 fhstatvfs.2
diff --git a/lib/libc/sys/chown.2 b/lib/libc/sys/chown.2
index 96b1b35ffc..7326161be8 100644
--- a/lib/libc/sys/chown.2
+++ b/lib/libc/sys/chown.2
@@ -33,13 +33,14 @@
 .\" $FreeBSD: src/lib/libc/sys/chown.2,v 1.12.2.6 2001/12/14 18:34:00 ru Exp $
 .\" $DragonFly: src/lib/libc/sys/chown.2,v 1.2 2003/06/17 04:26:47 dillon Exp $
 .\"
-.Dd April 19, 1994
+.Dd August 9, 2009
 .Dt CHOWN 2
 .Os
 .Sh NAME
 .Nm chown ,
 .Nm fchown ,
-.Nm lchown
+.Nm lchown ,
+.Nm fchownat
 .Nd change owner and group of a file
 .Sh LIBRARY
 .Lb libc
@@ -51,6 +52,8 @@
 .Fn fchown "int fd" "uid_t owner" "gid_t group"
 .Ft int
 .Fn lchown "const char *path" "uid_t owner" "gid_t group"
+.Ft int
+.Fn fchownat "int dirfd" "const char *path" "uid_t owner" "gid_t group" "int flags"
 .Sh DESCRIPTION
 The owner ID and group ID of the file
 named by
@@ -91,16 +94,56 @@ but does not follow symbolic links.
 .Pp
 One of the owner or group id's
 may be left unchanged by specifying it as -1.
+.Pp
+The
+.Fn fchownat
+function is equivalent to the
+.Fn chown
+or
+.Fn lchown
+functions except in the case where the
+.Fa path
+specifies a relative path.
+In this case the file to be opened is determined relative to the directory
+associated with the file descriptor
+.Fa dirfd
+instead of the current working directory.
+If
+.Fn fchownat
+is passed the special value
+.Dv AT_FDCWD
+in the
+.Fa dirfd
+parameter, the current working directory is used
+and the behavior is identical to a call to
+.Fn chown
+or
+.Fn lchown .
+.Pp
+The values for the
+.Fa flags
+are constructed by a bitwise-inclusive OR of flags from the following list,
+defined in
+.In fcntl.h :
+.Bl -tag -width indent
+.It Dv AT_SYMLINK_NOFOLLOW
+If
+.Fa path
+names a symbolic link, the mode of the symbolic link is changed.
+.El
 .Sh RETURN VALUES
 .Rv -std
 .Sh ERRORS
-.Fn Chown
-and
+.Fn Chown ,
 .Fn lchown
+and
+.Fn fchownat
 will fail and the file will be unchanged if:
 .Bl -tag -width Er
 .It Bq Er ENOTDIR
-A component of the path prefix is not a directory.
+A component of the path prefix or
+.Fa dirfd
+is not a directory.
 .It Bq Er ENAMETOOLONG
 A component of a pathname exceeded 255 characters,
 or an entire path name exceeded 1023 characters.
@@ -167,3 +210,8 @@ The
 function was added in
 .Fx 3.0
 to compensate for the loss of functionality.
+.Pp
+The
+.Fn fchownat
+system call appeared in
+.Dx 2.3 .
diff --git a/lib/libc_r/uthread/Makefile.inc b/lib/libc_r/uthread/Makefile.inc
index 67298faee5..eebb17751a 100644
--- a/lib/libc_r/uthread/Makefile.inc
+++ b/lib/libc_r/uthread/Makefile.inc
@@ -50,6 +50,7 @@ SRCS+= \
 	uthread_fchmod.c \
 	uthread_fchmodat.c \
 	uthread_fchown.c \
+	uthread_fchownat.c \
 	uthread_fcntl.c \
 	uthread_fd.c \
 	uthread_find_thread.c \
diff --git a/lib/libc_r/uthread/uthread_fchownat.c b/lib/libc_r/uthread/uthread_fchownat.c
new file mode 100644
index 0000000000..6a5ff7dcae
--- /dev/null
+++ b/lib/libc_r/uthread/uthread_fchownat.c
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2009 The DragonFly Project.  All rights reserved.
+ * 
+ * This code is derived from software contributed to The DragonFly Project
+ * by Nicolas Thery <nthery@gmail.com>
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name of The DragonFly Project nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific, prior written permission.
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <pthread.h>
+#include <unistd.h>
+#include "pthread_private.h"
+
+int
+_fchownat(int fd, const char *path, uid_t owner, gid_t group, int flags)
+{
+	int             ret;
+
+	if ((ret = _FD_LOCK(fd, FD_READ, NULL)) == 0) {
+		ret = __sys_fchownat(fd, path, owner, group, flags);
+		_FD_UNLOCK(fd, FD_READ);
+	}
+	return (ret);
+}
+
+__strong_reference(_fchownat, fchownat);
diff --git a/sys/kern/init_sysent.c b/sys/kern/init_sysent.c
index 6d69ef665f..65bfd122b2 100644
--- a/sys/kern/init_sysent.c
+++ b/sys/kern/init_sysent.c
@@ -540,4 +540,5 @@ struct sysent sysent[] = {
 	{ AS(openat_args), (sy_call_t *)sys_openat },	/* 504 = openat */
 	{ AS(fstatat_args), (sy_call_t *)sys_fstatat },	/* 505 = fstatat */
 	{ AS(fchmodat_args), (sy_call_t *)sys_fchmodat },	/* 506 = fchmodat */
+	{ AS(fchownat_args), (sy_call_t *)sys_fchownat },	/* 507 = fchownat */
 };
diff --git a/sys/kern/syscalls.c b/sys/kern/syscalls.c
index 007e6a967d..e1fa42216e 100644
--- a/sys/kern/syscalls.c
+++ b/sys/kern/syscalls.c
@@ -514,4 +514,5 @@ const char *syscallnames[] = {
 	"openat",			/* 504 = openat */
 	"fstatat",			/* 505 = fstatat */
 	"fchmodat",			/* 506 = fchmodat */
+	"fchownat",			/* 507 = fchownat */
 };
diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index 83fe3f1e0f..628a1387b9 100644
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -696,3 +696,5 @@
 					struct stat *sb, int flags); }
 506	STD	POSIX	{ int fchmodat(int fd, char *path, int mode, \
 					int flags); }
+507	STD	POSIX	{ int fchownat(int fd, char *path, int uid, int gid, \
+					int flags); }
diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
index 83bf5cf478..0c723e4194 100644
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -2906,6 +2906,32 @@ sys_fchown(struct fchown_args *uap)
 	return (error);
 }
 
+/*
+ * fchownat(int fd, char *path, int uid, int gid, int flags)
+ *
+ * Set ownership of file pointed to by fd/path.
+ */
+int
+sys_fchownat(struct fchownat_args *uap)
+{
+	struct nlookupdata nd;
+	struct file *fp;
+	int error;
+	int flags;
+
+	if (uap->flags & ~_AT_SYMLINK_MASK)
+		return (EINVAL);
+	flags = (uap->flags & AT_SYMLINK_NOFOLLOW) ? 0 : NLC_FOLLOW;
+
+	error = nlookup_init_at(&nd, &fp, uap->fd, uap->path, 
+				UIO_USERSPACE, flags);
+	if (error == 0)
+		error = kern_chown(&nd, uap->uid, uap->gid);
+	nlookup_done_at(&nd, fp);
+	return (error);
+}
+
+
 static int
 getutimes(const struct timeval *tvp, struct timespec *tsp)
 {
diff --git a/sys/sys/syscall-hide.h b/sys/sys/syscall-hide.h
index cb22bbddbb..6e83a94418 100644
--- a/sys/sys/syscall-hide.h
+++ b/sys/sys/syscall-hide.h
@@ -337,3 +337,4 @@ HIDE_BSD(getvfsstat)
 HIDE_POSIX(openat)
 HIDE_POSIX(fstatat)
 HIDE_POSIX(fchmodat)
+HIDE_POSIX(fchownat)
diff --git a/sys/sys/syscall.h b/sys/sys/syscall.h
index ff73c93fd3..e64115148e 100644
--- a/sys/sys/syscall.h
+++ b/sys/sys/syscall.h
@@ -348,4 +348,5 @@
 #define	SYS_openat	504
 #define	SYS_fstatat	505
 #define	SYS_fchmodat	506
-#define	SYS_MAXSYSCALL	507
+#define	SYS_fchownat	507
+#define	SYS_MAXSYSCALL	508
diff --git a/sys/sys/syscall.mk b/sys/sys/syscall.mk
index e027afdc3d..aee75a187b 100644
--- a/sys/sys/syscall.mk
+++ b/sys/sys/syscall.mk
@@ -288,4 +288,5 @@ MIASM =  \
 	getvfsstat.o \
 	openat.o \
 	fstatat.o \
-	fchmodat.o
+	fchmodat.o \
+	fchownat.o
diff --git a/sys/sys/sysproto.h b/sys/sys/sysproto.h
index 05db2a2f5b..6f80bc70be 100644
--- a/sys/sys/sysproto.h
+++ b/sys/sys/sysproto.h
@@ -2186,6 +2186,16 @@ struct	fchmodat_args {
 	int	mode;	char mode_[PAD_(int)];
 	int	flags;	char flags_[PAD_(int)];
 };
+struct	fchownat_args {
+#ifdef _KERNEL
+	struct sysmsg sysmsg;
+#endif
+	int	fd;	char fd_[PAD_(int)];
+	char *	path;	char path_[PAD_(char *)];
+	int	uid;	char uid_[PAD_(int)];
+	int	gid;	char gid_[PAD_(int)];
+	int	flags;	char flags_[PAD_(int)];
+};
 
 #ifdef COMPAT_43
 
@@ -2775,6 +2785,7 @@ int	sys_getvfsstat (struct getvfsstat_args *);
 int	sys_openat (struct openat_args *);
 int	sys_fstatat (struct fstatat_args *);
 int	sys_fchmodat (struct fchmodat_args *);
+int	sys_fchownat (struct fchownat_args *);
 
 #endif /* !_SYS_SYSPROTO_H_ */
 #undef PAD_
diff --git a/sys/sys/sysunion.h b/sys/sys/sysunion.h
index f2bc2fe56a..4d70eec7d1 100644
--- a/sys/sys/sysunion.h
+++ b/sys/sys/sysunion.h
@@ -393,4 +393,5 @@ union sysunion {
 	struct	openat_args openat;
 	struct	fstatat_args fstatat;
 	struct	fchmodat_args fchmodat;
+	struct	fchownat_args fchownat;
 };