Add fchmodat(2).

libc/Makefile

@@ -140,6 +140,7 @@ _Exit.o \
 exit.o \
 faccessat.o \
 fchdir.o \
+fchmodat.o \
 fchmod.o \
 fchownat.o \
 fchown.o \

libc/fchmodat.cpp

@@ -0,0 +1,34 @@
+/*******************************************************************************
+
+    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/>.
+
+    fchmodat.cpp
+    Changes the mode bits of a file.
+
+*******************************************************************************/
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/syscall.h>
+
+DEFN_SYSCALL4(int, sys_fchmodat, SYSCALL_FCHMODAT, int, const char*, mode_t, int);
+
+extern "C" int fchmodat(int dirfd, const char* path, mode_t mode, int flags)
+{
+	return sys_fchmodat(dirfd, path, mode, flags);
+}

libc/include/sys/stat.h

@@ -48,6 +48,7 @@ __BEGIN_DECLS
 
 int chmod(const char* path, mode_t mode);
 int fchmod(int fd, mode_t mode);
+int fchmodat(int dirfd, const char* path, mode_t mode, int flags);
 int fstat(int fd, struct stat* st);
 int fstatat(int dirfd, const char* path, struct stat* buf, int flags);
 int lstat(const char* restrict path, struct stat* restrict st);

sortix/include/sortix/syscallnum.h

@@ -90,6 +90,7 @@
 #define SYSCALL_FCHOWNAT 66
 #define SYSCALL_FCHOWN 67
 #define SYSCALL_FCHMOD 68
-#define SYSCALL_MAX_NUM 69 /* index of highest constant + 1 */
+#define SYSCALL_FCHMODAT 69
+#define SYSCALL_MAX_NUM 70 /* index of highest constant + 1 */
 
 #endif

sortix/io.cpp

@@ -393,14 +393,17 @@ static int sys_fchmod(int fd, mode_t mode)
 	return desc->chmod(&ctx, mode);
 }
 
-static int sys_chmod(const char* path, mode_t mode)
+static int sys_fchmodat(int dirfd, const char* path, mode_t mode, 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;
@@ -409,6 +412,11 @@ static int sys_chmod(const char* path, mode_t mode)
 	return desc->chmod(&ctx, mode);
 }
 
+static int sys_chmod(const char* path, mode_t mode)
+{
+	return sys_fchmodat(AT_FDCWD, path, mode, 0);
+}
+
 static int sys_link(const char* oldpath, const char* newpath)
 {
 	ioctx_t ctx; SetupUserIOCtx(&ctx);
@@ -487,6 +495,7 @@ 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_FCHMODAT, (void*) sys_fchmodat);
 	Syscall::Register(SYSCALL_FCHMOD, (void*) sys_fchmod);
 	Syscall::Register(SYSCALL_FCHOWNAT, (void*) sys_fchownat);
 	Syscall::Register(SYSCALL_FCHOWN, (void*) sys_fchown);