Add fchdirat(2).

libc/Makefile

@@ -198,6 +198,7 @@ _exit.o \
 _Exit.o \
 exit.o \
 faccessat.o \
+fchdirat.o \
 fchdir.o \
 fchmodat.o \
 fchmod.o \

libc/chdir.cpp

@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
+    Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013
 
     This file is part of the Sortix C Library.
 
@@ -22,12 +22,10 @@
 
 *******************************************************************************/
 
-#include <sys/syscall.h>
+#include <fcntl.h>
 #include <unistd.h>
 
-DEFN_SYSCALL1(int, SysChDir, SYSCALL_CHDIR, const char*);
-
 extern "C" int chdir(const char* path)
 {
-	return SysChDir(path);
+	return fchdirat(AT_FDCWD, path);
 }

libc/fchdirat.cpp

@@ -0,0 +1,34 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2013
+
+    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/>.
+
+    fchdirat.cpp
+    Changes the current working directory.
+
+*******************************************************************************/
+
+#include <sys/syscall.h>
+
+#include <unistd.h>
+
+DEFN_SYSCALL2(int, sys_fchdirat, SYSCALL_FCHDIRAT, int, const char*);
+
+extern "C" int fchdirat(int dirfd, const char* path)
+{
+	return sys_fchdirat(dirfd, path);
+}

libc/include/unistd.h

@@ -316,6 +316,7 @@ int execvp(const char*, char* const []);
 pid_t fork(void);
 int faccessat(int, const char*, int, int);
 int fchdir(int);
+int fchdirat(int, const char*);
 int fchown(int, uid_t, gid_t);
 int fchownat(int, const char*, uid_t, gid_t, int);
 int fsync(int);

sortix/include/sortix/syscallnum.h

@@ -129,6 +129,7 @@
 #define SYSCALL_CLOCK_NANOSLEEP 105
 #define SYSCALL_TIMENS 106
 #define SYSCALL_UMASK 107
-#define SYSCALL_MAX_NUM 108 /* index of highest constant + 1 */
+#define SYSCALL_FCHDIRAT 108
+#define SYSCALL_MAX_NUM 109 /* index of highest constant + 1 */
 
 #endif

sortix/io.cpp

@@ -367,14 +367,14 @@ static int sys_fchdir(int fd)
 	return 0;
 }
 
-static int sys_chdir(const char* path)
+static int sys_fchdirat(int dirfd, const char* path)
 {
 	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);
 	Ref<Descriptor> desc = from->open(&ctx, relpath, O_READ | O_DIRECTORY);
 	from.Reset();
 	delete[] pathcopy;
@@ -384,6 +384,12 @@ static int sys_chdir(const char* path)
 	return 0;
 }
 
+// TODO: This system call is replaced by sys_fchownat, will be removed soon.
+static int sys_chdir(const char* path)
+{
+	return sys_fchdirat(AT_FDCWD, path);
+}
+
 static int sys_fchown(int fd, uid_t owner, gid_t group)
 {
 	Ref<Descriptor> desc = CurrentProcess()->GetDescriptor(fd);
@@ -864,6 +870,7 @@ void Init()
 	Syscall::Register(SYSCALL_DUP2, (void*) sys_dup2);
 	Syscall::Register(SYSCALL_DUP, (void*) sys_dup);
 	Syscall::Register(SYSCALL_FACCESSAT, (void*) sys_faccessat);
+	Syscall::Register(SYSCALL_FCHDIRAT, (void*) sys_fchdirat);
 	Syscall::Register(SYSCALL_FCHDIR, (void*) sys_fchdir);
 	Syscall::Register(SYSCALL_FCHMODAT, (void*) sys_fchmodat);
 	Syscall::Register(SYSCALL_FCHMOD, (void*) sys_fchmod);