Add fchdir(2).

libc/Makefile

@@ -139,6 +139,7 @@ _exit.o \
 _Exit.o \
 exit.o \
 faccessat.o \
+fchdir.o \
 fchmod.o \
 fcloseall.o \
 fcntl.o \

libc/fchdir.cpp

@@ -0,0 +1,33 @@
+/*******************************************************************************
+
+    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/>.
+
+    fchdir.cpp
+    Changes the current working directory.
+
+*******************************************************************************/
+
+#include <sys/syscall.h>
+#include <unistd.h>
+
+DEFN_SYSCALL1(int, sys_fchdir, SYSCALL_FCHDIR, int);
+
+extern "C" int fchdir(int fd)
+{
+	return sys_fchdir(fd);
+}

libc/include/unistd.h

@@ -92,7 +92,6 @@ size_t confstr(int, char*, size_t);
 char* crypt(const char*, const char*);
 char* ctermid(char*);
 void encrypt(char [64], int);
-int fchdir(int);
 int fchown(int, uid_t, gid_t);
 int fchownat(int, const char*, uid_t, gid_t, int);
 int fdatasync(int);
@@ -161,6 +160,7 @@ int execve(const char*, char* const [], char* const []);
 int execvp(const char*, char* const []);
 pid_t fork(void);
 int faccessat(int, const char*, int, int);
+int fchdir(int);
 int ftruncate(int, off_t);
 char* getcwd(char*, size_t);
 char* get_current_dir_name(void);

sortix/include/sortix/syscallnum.h

@@ -85,6 +85,7 @@
 #define SYSCALL_UNLINKAT 61
 #define SYSCALL_FACCESSAT 62
 #define SYSCALL_MKDIRAT 63
-#define SYSCALL_MAX_NUM 64 /* index of highest constant + 1 */
+#define SYSCALL_FCHDIR 64
+#define SYSCALL_MAX_NUM 65 /* index of highest constant + 1 */
 
 #endif

sortix/io.cpp

@@ -316,6 +316,18 @@ static ssize_t sys_readdirents(int fd, kernel_dirent* dirent, size_t size/*,
 	return desc->readdirents(&ctx, dirent, size, 1 /*maxcount*/);
 }
 
+static int sys_fchdir(int fd)
+{
+	Process* process = CurrentProcess();
+	Ref<Descriptor> desc = process->GetDescriptor(fd);
+	if ( !desc )
+		return -1;
+	if ( !S_ISDIR(desc->type) )
+		return errno = ENOTDIR, -1;
+	process->SetCWD(desc);
+	return 0;
+}
+
 static int sys_chdir(const char* path)
 {
 	char* pathcopy = GetStringFromUser(path);
@@ -442,6 +454,7 @@ void Init()
 	Syscall::Register(SYSCALL_DUP, (void*) sys_dup);
 	Syscall::Register(SYSCALL_DUP2, (void*) sys_dup2);
 	Syscall::Register(SYSCALL_FACCESSAT, (void*) sys_faccessat);
+	Syscall::Register(SYSCALL_FCHDIR, (void*) sys_fchdir);
 	Syscall::Register(SYSCALL_FCNTL, (void*) sys_fcntl);
 	Syscall::Register(SYSCALL_FSTATAT, (void*) sys_fstatat);
 	Syscall::Register(SYSCALL_FSTAT, (void*) sys_fstat);