Add linkat(2).

libc/Makefile

@@ -167,6 +167,7 @@ ioleast.o \
 isatty.o \
 kernelinfo.o \
 kill.o \
+linkat.o \
 link.o \
 localeconv.o \
 lseek.o \

libc/include/unistd.h

@@ -110,7 +110,6 @@ pid_t getpgrp(void);
 pid_t getsid(pid_t);
 uid_t getuid(void);
 int lchown(const char*, uid_t, gid_t);
-int linkat(int, const char*, int, const char*, int);
 int lockf(int, int, off_t);
 int nice(int);
 long pathconf(const char*, int);
@@ -168,6 +167,7 @@ pid_t getpid(void);
 pid_t getppid(void);
 int isatty(int);
 int link(const char*, const char*);
+int linkat(int, const char*, int, const char*, int);
 off_t lseek(int, off_t, int);
 int pipe(int [2]);
 ssize_t pread(int, void*, size_t, off_t);

libc/linkat.cpp

@@ -0,0 +1,37 @@
+/*******************************************************************************
+
+    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/>.
+
+    linkat.cpp
+    Give a new name to a file.
+
+*******************************************************************************/
+
+#include <sys/syscall.h>
+
+#include <fcntl.h>
+#include <unistd.h>
+
+DEFN_SYSCALL5(int, sys_linkat, SYSCALL_LINKAT, int, const char*, int, const char*, int);
+
+extern "C" int linkat(int olddirfd, const char* oldpath,
+                      int newdirfd, const char* newpath,
+                      int flags)
+{
+	return sys_linkat(olddirfd, oldpath, newdirfd, newpath, flags);
+}

sortix/include/sortix/syscallnum.h

@@ -91,6 +91,7 @@
 #define SYSCALL_FCHOWN 67
 #define SYSCALL_FCHMOD 68
 #define SYSCALL_FCHMODAT 69
-#define SYSCALL_MAX_NUM 70 /* index of highest constant + 1 */
+#define SYSCALL_LINKAT 70
+#define SYSCALL_MAX_NUM 71 /* index of highest constant + 1 */
 
 #endif

sortix/io.cpp

@@ -417,15 +417,21 @@ 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)
+static int sys_linkat(int olddirfd, const char* oldpath,
+                      int newdirfd, const char* newpath,
+                      int flags)
 {
+	if ( flags )
+		return errno = ENOTSUP, -1;
+
 	ioctx_t ctx; SetupUserIOCtx(&ctx);
 
 	char* newpathcopy = GetStringFromUser(newpath);
 	if ( !newpathcopy )
 		return -1;
 	const char* newrelpath = newpathcopy;
-	Ref<Descriptor> newfrom(PrepareLookup(&newrelpath));
+	Ref<Descriptor> newfrom(PrepareLookup(&newrelpath, newdirfd));
+	if ( !newfrom ) { delete[] newpathcopy; return -1; }
 
 	char* final_elem;
 	Ref<Descriptor> dir = OpenDirContainingPath(&ctx, newfrom, newpathcopy,
@@ -437,7 +443,8 @@ static int sys_link(const char* oldpath, const char* newpath)
 	char* oldpathcopy = GetStringFromUser(oldpath);
 	if ( !oldpathcopy ) { delete[] final_elem; return -1; }
 	const char* oldrelpath = oldpathcopy;
-	Ref<Descriptor> oldfrom(PrepareLookup(&oldrelpath));
+	Ref<Descriptor> oldfrom = PrepareLookup(&oldrelpath, olddirfd);
+	if ( !oldfrom ) { delete[] oldpathcopy; delete[] final_elem; return -1; }
 
 	Ref<Descriptor> file = oldfrom->open(&ctx, oldrelpath, O_RDONLY);
 	delete[] oldpathcopy;
@@ -448,6 +455,11 @@ static int sys_link(const char* oldpath, const char* newpath)
 	return ret;
 }
 
+static int sys_link(const char* oldpath, const char* newpath)
+{
+	return sys_linkat(AT_FDCWD, oldpath, AT_FDCWD, newpath, 0);
+}
+
 static int sys_settermmode(int fd, unsigned mode)
 {
 	Ref<Descriptor> desc = CurrentProcess()->GetDescriptor(fd);
@@ -505,6 +517,7 @@ void Init()
 	Syscall::Register(SYSCALL_FTRUNCATE, (void*) sys_ftruncate);
 	Syscall::Register(SYSCALL_GETTERMMODE, (void*) sys_gettermmode);
 	Syscall::Register(SYSCALL_ISATTY, (void*) sys_isatty);
+	Syscall::Register(SYSCALL_LINKAT, (void*) sys_linkat);
 	Syscall::Register(SYSCALL_LINK, (void*) sys_link);
 	Syscall::Register(SYSCALL_MKDIRAT, (void*) sys_mkdirat);
 	Syscall::Register(SYSCALL_MKDIR, (void*) sys_mkdir);