From eef01078bb79d26cf4d571ec2d7e3fcb904373de Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Fri, 30 Sep 2022 17:04:18 -0300
Subject: [PATCH] syscalls: fstatat

---
 src/arch/x86_64/syscall.asm |  4 +-
 src/sys/syscalls/fstatat.c  | 79 +++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+), 1 deletion(-)
 create mode 100644 src/sys/syscalls/fstatat.c

diff --git a/src/arch/x86_64/syscall.asm b/src/arch/x86_64/syscall.asm
index b00ffdba..bbcfb8d3 100644
--- a/src/arch/x86_64/syscall.asm
+++ b/src/arch/x86_64/syscall.asm
@@ -24,7 +24,8 @@ extern syscall_getpid
 extern syscall_getdirent
 extern syscall_ioctl
 extern syscall_chdir
-func_count equ 23
+extern syscall_fstatat
+func_count equ 24
 
 
 func_table:
@@ -51,6 +52,7 @@ func_table:
 	dq syscall_getdirent
 	dq syscall_ioctl
 	dq syscall_chdir
+	dq syscall_fstatat
 section .text
 global asm_syscall_entry
 
diff --git a/src/sys/syscalls/fstatat.c b/src/sys/syscalls/fstatat.c
new file mode 100644
index 00000000..55a4ee25
--- /dev/null
+++ b/src/sys/syscalls/fstatat.c
@@ -0,0 +1,79 @@
+#include <kernel/syscalls.h>
+#include <sys/stat.h>
+#include <kernel/fd.h>
+#include <arch/cls.h>
+#include <kernel/vfs.h>
+#include <arch/spinlock.h>
+#include <string.h>
+
+#define AT_FDCWD -100
+
+syscallret syscall_fstatat(int ifd, char* path, stat* st, int flags){
+	syscallret retv;
+	retv.ret = -1;
+
+	if(flags){
+		retv.errno = EINVAL;
+		return retv;
+	}
+
+	if(st > USER_SPACE_END || path > USER_SPACE_END){
+		retv.errno = EFAULT;
+		return retv;
+	}
+
+	size_t len = strlen(path);
+	
+	char buff[len+1];
+
+	strcpy(buff, path);
+
+	proc_t* proc = arch_getcls()->thread->proc;
+	
+	dirnode_t* targnode;
+	fd_t* fd;
+
+	if(ifd != AT_FDCWD){
+
+		
+		int err = fd_access(&proc->fdtable, &fd, ifd);
+
+		if(err){
+			retv.errno = err;
+			return retv;
+		}
+
+		if(buff[0] != '/' && GETTYPE(fd->mode) != TYPE_DIR){
+			retv.errno = ENOTDIR;
+			goto _fail;
+		}
+		
+		targnode = fd->node;
+
+	}
+	else
+		targnode = proc->cwd;
+	
+
+	vnode_t* node;
+
+	retv.errno = vfs_open(&node, buff[0] == '/' ? proc->root : targnode, buff);
+
+	if(retv.errno)
+		goto _fail;
+
+
+	memcpy(st, &node->st, sizeof(stat)); // XXX user memcpy
+
+	vfs_close(node);
+
+	_fail:
+	
+	if(ifd != AT_FDCWD)
+		fd_release(fd);
+
+	retv.ret = 0;
+
+	return retv;
+
+}