Kernel: Implement SYS_FSTAT

kernel/kernel/Syscall.cpp

@@ -128,9 +128,9 @@ namespace Kernel
 		return ret.value();
 	}
 
-	long sys_stat(const char* path, struct stat* buf, int flags)
+	long sys_fstat(int fd, struct stat* buf)
 	{
-		auto ret = Process::current().stat(path, buf, flags);
+		auto ret = Process::current().fstat(fd, buf);
 		if (ret.is_error())
 			return -ret.error().get_error_code();
 		return 0;
@@ -217,8 +217,8 @@ namespace Kernel
 		case SYS_WAIT:
 			ret = sys_wait((pid_t)arg1, (int*)arg2, (int)arg3);
 			break;
-		case SYS_STAT:
+		case SYS_FSTAT:
-			ret = sys_stat((const char*)arg1, (struct stat*)arg2, (int)arg3);
+			ret = sys_fstat((int)arg1, (struct stat*)arg2);
 			break;
 		case SYS_SETENVP:
 			ret = sys_setenvp((char**)arg1);

libc/include/sys/syscall.h

@@ -22,7 +22,7 @@ __BEGIN_DECLS
 #define SYS_EXEC 15
 #define SYS_REALLOC 16
 #define SYS_WAIT 17
-#define SYS_STAT 18
+#define SYS_FSTAT 18
 #define SYS_SETENVP 19
 #define SYS_READ_DIR_ENTRIES 20
 

libc/sys/stat.cpp

@@ -1,14 +1,46 @@
+#include <errno.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/syscall.h>
 #include <unistd.h>
 
+int fstat(int fildes, struct stat* buf)
+{
+	return syscall(SYS_FSTAT, fildes, buf);
+}
+
+int fstatat(int fd, const char* __restrict path, struct stat* __restrict buf, int flag)
+{
+	if (flag & ~AT_SYMLINK_NOFOLLOW)
+	{
+		errno = EINVAL;
+		return -1;
+	}
+
+	int target = openat(fd, path, (flag & AT_SYMLINK_NOFOLLOW) ? O_NOFOLLOW : 0);
+	if (target == -1)
+		return -1;
+	int ret = fstat(target, buf);
+	close(target);
+	return ret;
+}
+
 int lstat(const char* __restrict path, struct stat* __restrict buf)
 {
-    return syscall(SYS_STAT, path, buf, O_RDONLY | O_NOFOLLOW);
+	int fd = open(path, O_SEARCH | O_NOFOLLOW);
+	if (fd == -1)
+		return -1;
+	int ret = fstat(fd, buf);
+	close(fd);
+	return ret;
 }
 
 int stat(const char* __restrict path, struct stat* __restrict buf)
 {
-    return syscall(SYS_STAT, path, buf, O_RDONLY);
+	int fd = open(path, O_SEARCH);
+	if (fd == -1)
+		return -1;
+	int ret = fstat(fd, buf);
+	close(fd);
+	return ret;
 }

libc/unistd.cpp

@@ -149,12 +149,11 @@ long syscall(long syscall, ...)
 			ret = Kernel::syscall(SYS_WAIT, pid, (uintptr_t)stat_loc, options);
 			break;
 		}
-		case SYS_STAT:
+		case SYS_FSTAT:
 		{
-			const char* path = va_arg(args, const char*);
+			int fd = va_arg(args, int);
 			struct stat* buf = va_arg(args, struct stat*);
-			int flags = va_arg(args, int);
+			ret = Kernel::syscall(SYS_FSTAT, (uintptr_t)fd, (uintptr_t)buf);
-			ret = Kernel::syscall(SYS_STAT, (uintptr_t)path, (uintptr_t)buf, flags);
 			break;
 		}
 		case SYS_SETENVP: