syscalls: unlinkat

kernel-src/arch/x86-64/syscall.asm

@@ -24,6 +24,7 @@ extern syscall_chdir
 extern syscall_pipe2
 extern syscall_isatty
 extern syscall_faccessat
+extern syscall_unlinkat
 syscalltab:
 dq syscall_print
 dq syscall_mmap
@@ -50,7 +51,8 @@ dq syscall_chdir
 dq syscall_pipe2
 dq syscall_isatty
 dq syscall_faccessat
-syscallcount equ 25
+dq syscall_unlinkat
+syscallcount equ 26
 section .text
 global arch_syscall_entry
 ; on entry:

kernel-src/arch/x86-64/syscalllog.c

@@ -30,7 +30,8 @@ static char *name[] = {
 	"chdir",
 	"pipe2",
 	"isatty",
-	"faccessat"
+	"faccessat",
+	"unlinkat"
 };
 
 static char *args[] = {
@@ -58,7 +59,8 @@ static char *args[] = {
 	"path %s", // chdir
 	"flags %d", // pipe2
 	"fd %d", // isatty
-	"dirfd %d pathname %s mode %d flags %d" // faccessat
+	"dirfd %d pathname %s mode %d flags %d", // faccessat
+	"dirfd %d pathname %d flags %d" // unlinkat
 };
 
 __attribute__((no_caller_saved_registers)) void arch_syscall_log(int syscall, uint64_t a1, uint64_t a2, uint64_t a3, uint64_t a4, uint64_t a5, uint64_t a6) {

kernel-src/sys/syscalls/unlinkat.c

@@ -0,0 +1,78 @@
+#include <kernel/syscalls.h>
+#include <kernel/file.h>
+#include <kernel/alloc.h>
+#include <kernel/vfs.h>
+#include <arch/cpu.h>
+#include <string.h>
+
+#define AT_SYMLINK_NOFOLLOW 0x100
+
+syscallret_t syscall_unlinkat(context_t *, int dirfd, const char *upath, int flags) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	size_t pathlen = strlen(upath) + 1;
+	char *path = alloc(pathlen);
+	if (path == NULL) {
+		ret.errno = ENOMEM;
+		return ret;
+	}
+
+	// TODO safe strcopy
+	strcpy(path, upath);
+
+	vnode_t *dirnode = NULL;
+	file_t *file = NULL;
+
+	char *component = alloc(pathlen);
+	if (component == NULL) {
+		ret.errno = ENOMEM;
+		goto cleanup;
+	}
+
+	if (*path == '/') {
+		dirnode = sched_getroot();
+	} else if (dirfd == AT_FDCWD) {
+		dirnode = sched_getcwd();
+	} else {
+		file = fd_get(dirfd);
+		if (file == NULL) {
+			ret.errno = EBADF;
+			goto cleanup;
+		}
+
+		dirnode = file->vnode;
+
+		if (dirnode->type != V_TYPE_DIR) {
+			ret.errno = ENOTDIR;
+			goto cleanup;
+		}
+	}
+
+	// TODO rmdir flag
+
+	vnode_t *node = NULL;
+	ret.errno = vfs_lookup(&node, dirnode, path, component, VFS_LOOKUP_NOLINK | VFS_LOOKUP_PARENT);
+	if (ret.errno)
+		goto cleanup;
+
+	ret.errno = VOP_UNLINK(node, component, &_cpu()->thread->proc->cred);
+	ret.ret = ret.errno ? -1 : 0;
+
+	cleanup:
+	if (component)
+		free(component);
+
+	if (node)
+		VOP_RELEASE(node);
+
+	if (file)
+		fd_release(file);
+	else
+		VOP_RELEASE(dirnode);
+
+	free(path);
+
+	return ret;
+}