From cb4569c6157489111a23b3555aeb7dae64d4a77b Mon Sep 17 00:00:00 2001
From: Jonas 'Sortie' Termansen <sortie@maxsi.org>
Date: Wed, 24 Oct 2012 19:43:11 +0200
Subject: [PATCH] Add fchownat(2).

---
 libc/Makefile                      |  1 +
 libc/fchownat.cpp                  | 36 ++++++++++++++++++++++++++++++
 libc/include/unistd.h              |  2 +-
 sortix/include/sortix/syscallnum.h |  3 ++-
 sortix/io.cpp                      | 15 +++++++++++--
 5 files changed, 53 insertions(+), 4 deletions(-)
 create mode 100644 libc/fchownat.cpp

diff --git a/libc/Makefile b/libc/Makefile
index ff9e2702..57399489 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -141,6 +141,7 @@ exit.o \
 faccessat.o \
 fchdir.o \
 fchmod.o \
+fchownat.o \
 fcloseall.o \
 fcntl.o \
 fddir-sortix.o \
diff --git a/libc/fchownat.cpp b/libc/fchownat.cpp
new file mode 100644
index 00000000..3608e0a6
--- /dev/null
+++ b/libc/fchownat.cpp
@@ -0,0 +1,36 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2012.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    fchownat.cpp
+    Changes the owner and group of a file.
+
+*******************************************************************************/
+
+#include <sys/types.h>
+#include <sys/syscall.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+
+DEFN_SYSCALL5(int, sys_fchownat, SYSCALL_FCHOWNAT, int, const char*, uid_t, gid_t, int);
+
+extern "C" int fchownat(int dirfd, const char* path, uid_t owner, gid_t group, int flags)
+{
+	return sys_fchownat(dirfd, path, owner, group, flags);
+}
diff --git a/libc/include/unistd.h b/libc/include/unistd.h
index 916a263d..866399c4 100644
--- a/libc/include/unistd.h
+++ b/libc/include/unistd.h
@@ -93,7 +93,6 @@ char* crypt(const char*, const char*);
 char* ctermid(char*);
 void encrypt(char [64], int);
 int fchown(int, uid_t, gid_t);
-int fchownat(int, const char*, uid_t, gid_t, int);
 int fdatasync(int);
 int fexecve(int, char* const [], char* const []);
 long fpathconf(int, int);
@@ -161,6 +160,7 @@ int execvp(const char*, char* const []);
 pid_t fork(void);
 int faccessat(int, const char*, int, int);
 int fchdir(int);
+int fchownat(int, const char*, uid_t, gid_t, int);
 int ftruncate(int, off_t);
 char* getcwd(char*, size_t);
 char* get_current_dir_name(void);
diff --git a/sortix/include/sortix/syscallnum.h b/sortix/include/sortix/syscallnum.h
index 7707658a..26c07234 100644
--- a/sortix/include/sortix/syscallnum.h
+++ b/sortix/include/sortix/syscallnum.h
@@ -87,6 +87,7 @@
 #define SYSCALL_MKDIRAT 63
 #define SYSCALL_FCHDIR 64
 #define SYSCALL_TRUNCATEAT 65
-#define SYSCALL_MAX_NUM 66 /* index of highest constant + 1 */
+#define SYSCALL_FCHOWNAT 66
+#define SYSCALL_MAX_NUM 67 /* index of highest constant + 1 */
 
 #endif
diff --git a/sortix/io.cpp b/sortix/io.cpp
index d4034e3e..0f1ed73d 100644
--- a/sortix/io.cpp
+++ b/sortix/io.cpp
@@ -351,14 +351,19 @@ static int sys_chdir(const char* path)
 	return 0;
 }
 
-static int sys_chown(const char* path, uid_t owner, gid_t group)
+// TODO: fchown(2)
+
+static int sys_fchownat(int dirfd, const char* path, uid_t owner, gid_t group, int flags)
 {
+	if ( flags )
+		return errno = ENOTSUP, -1;
 	char* pathcopy = GetStringFromUser(path);
 	if ( !pathcopy )
 		return -1;
 	ioctx_t ctx; SetupUserIOCtx(&ctx);
 	const char* relpath = pathcopy;
-	Ref<Descriptor> from = PrepareLookup(&relpath);
+	Ref<Descriptor> from = PrepareLookup(&relpath, dirfd);
+	if ( !from ) { delete[] pathcopy; return -1; }
 	Ref<Descriptor> desc = from->open(&ctx, relpath, O_WRONLY);
 	from.Reset();
 	delete[] pathcopy;
@@ -367,6 +372,11 @@ static int sys_chown(const char* path, uid_t owner, gid_t group)
 	return desc->chown(&ctx, owner, group);
 }
 
+static int sys_chown(const char* path, uid_t owner, gid_t group)
+{
+	return sys_fchownat(AT_FDCWD, path, owner, group, 0);
+}
+
 static int sys_chmod(const char* path, mode_t mode)
 {
 	char* pathcopy = GetStringFromUser(path);
@@ -461,6 +471,7 @@ void Init()
 	Syscall::Register(SYSCALL_DUP2, (void*) sys_dup2);
 	Syscall::Register(SYSCALL_FACCESSAT, (void*) sys_faccessat);
 	Syscall::Register(SYSCALL_FCHDIR, (void*) sys_fchdir);
+	Syscall::Register(SYSCALL_FCHOWNAT, (void*) sys_fchownat);
 	Syscall::Register(SYSCALL_FCNTL, (void*) sys_fcntl);
 	Syscall::Register(SYSCALL_FSTATAT, (void*) sys_fstatat);
 	Syscall::Register(SYSCALL_FSTAT, (void*) sys_fstat);