syscalls: ftruncate

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

@@ -35,6 +35,7 @@ extern syscall_fchmodat
 extern syscall_umask
 extern syscall_poll
 extern syscall_nanosleep
+extern syscall_ftruncate
 syscalltab:
 dq syscall_print
 dq syscall_mmap
@@ -72,7 +73,8 @@ dq syscall_fchmodat
 dq syscall_umask
 dq syscall_poll
 dq syscall_nanosleep
-syscallcount equ 36
+dq syscall_ftruncate
+syscallcount equ 37
 section .text
 global arch_syscall_entry
 ; on entry:

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

@@ -43,7 +43,8 @@ static char *name[] = {
 	"fchmodat",
 	"umask",
 	"poll",
-	"nanosleep"
+	"nanosleep",
+	"ftruncate"
 };
 
 static char *args[] = {
@@ -82,7 +83,8 @@ static char *args[] = {
 	"dirfd %d path %s mode %o flags %d", // fchmodat
 	"mode %o", // umask
 	"fds %p nfds %d timeout %d", // poll
-	"time %p remaining %p" // nanosleep
+	"time %p remaining %p", // nanosleep
+	"fd %d size %lu" // ftruncate
 };
 
 #endif

kernel-src/sys/syscalls/truncate.c

@@ -0,0 +1,27 @@
+#include <kernel/syscalls.h>
+
+syscallret_t syscall_ftruncate(int fd, size_t size) {
+	syscallret_t ret = {
+		.ret = -1
+	};
+
+	file_t *file = fd_get(fd);
+	if (file == NULL) {
+		ret.errno = EBADF;
+		return ret;
+	}
+
+	if ((file->flags & FILE_WRITE) == 0 || file->vnode->type != V_TYPE_REGULAR) {
+		ret.errno = EINVAL;
+		goto cleanup;
+	}
+
+	ret.errno = VOP_RESIZE(file->vnode, size, &_cpu()->thread->proc->cred);
+	ret.ret = ret.errno ? -1 : 0;
+
+	cleanup:
+
+	fd_release(file);
+
+	return ret;	
+}