syscalls: getdents syscall

kernel-src/sys/syscalls/getdent.c

@@ -0,0 +1,58 @@
+#include <kernel/syscalls.h>
+#include <kernel/file.h>
+#include <kernel/vmm.h>
+#include <errno.h>
+#include <kernel/alloc.h>
+
+syscallret_t syscall_getdents(context_t *, int dirfd, void *ubuffer, size_t readmax) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	if (ubuffer > USERSPACE_END) {
+		ret.errno = EFAULT;
+		return ret;
+	}
+
+	size_t count = readmax / sizeof(dent_t);
+
+	if (count == 0) {
+		ret.errno = EINVAL;
+		return ret;
+	}
+
+	dent_t *buffer = alloc(readmax);
+	if (buffer == NULL) {
+		ret.errno = ENOMEM;
+		return ret;
+	}
+
+	file_t *fd = fd_get(dirfd);
+	if (fd == NULL) {
+		free(buffer);
+		ret.errno = EBADF;
+		return ret;
+	}
+
+	if (fd->vnode->type != V_TYPE_DIR) {
+		ret.errno = ENOTDIR;
+		goto cleanup;
+	}
+
+	ret.errno = VOP_GETDENTS(fd->vnode, buffer, count, fd->offset, &ret.ret); 
+
+	if (ret.errno)
+		goto cleanup;
+
+	fd->offset += ret.ret;
+
+	ret.ret *= sizeof(dent_t);
+
+	// TODO safe memcpy
+	memcpy(ubuffer, buffer, ret.ret);
+
+	cleanup:
+	free(buffer);
+	fd_release(fd);
+	return ret;
+}