From 4834353501fa92f8ba5dbfa80f557981d3bf8ef5 Mon Sep 17 00:00:00 2001
From: Matheus <matheusuky@gmail.com>
Date: Fri, 21 Oct 2022 13:25:29 -0300
Subject: [PATCH] syscalls: link at

---
 src/arch/x86_64/syscall.asm |  4 +-
 src/fs/tmpfs.c              |  6 ++-
 src/sys/syscalls/linkat.c   | 95 +++++++++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+), 3 deletions(-)
 create mode 100644 src/sys/syscalls/linkat.c

diff --git a/src/arch/x86_64/syscall.asm b/src/arch/x86_64/syscall.asm
index 8e5993b7..8f8e9b63 100644
--- a/src/arch/x86_64/syscall.asm
+++ b/src/arch/x86_64/syscall.asm
@@ -42,7 +42,8 @@ extern syscall_connect
 extern syscall_accept
 extern syscall_nanosleep
 extern syscall_fchmod
-func_count equ 41
+extern syscall_linkat
+func_count equ 42
 
 
 func_table:
@@ -87,6 +88,7 @@ func_table:
 	dq syscall_accept
 	dq syscall_nanosleep
 	dq syscall_fchmod
+	dq syscall_linkat
 section .text
 global asm_syscall_entry
 
diff --git a/src/fs/tmpfs.c b/src/fs/tmpfs.c
index af6836b0..0632f6fa 100644
--- a/src/fs/tmpfs.c
+++ b/src/fs/tmpfs.c
@@ -220,13 +220,15 @@ static int tmpfs_readlink(vnode_t *node, char** buff, size_t* linksize){
 
 }
 
-static int tmpfs_link(dirnode_t* parent, char* name, vnode_t* link){
-	
+static int tmpfs_link(dirnode_t* parent, vnode_t* link, char* name){
+
 	if(!hashtable_insert(&parent->children, name, link))
 		return ENOMEM;
 
 	++link->st.st_nlink;
 
+	return 0;
+
 }
 
 static fscalls_t funcs = {
diff --git a/src/sys/syscalls/linkat.c b/src/sys/syscalls/linkat.c
new file mode 100644
index 00000000..91c75735
--- /dev/null
+++ b/src/sys/syscalls/linkat.c
@@ -0,0 +1,95 @@
+#include <kernel/syscalls.h>
+#include <kernel/vfs.h>
+#include <sys/types.h>
+#include <arch/cls.h>
+#include <kernel/fd.h>
+#include <kernel/sched.h>
+#include <string.h>
+
+
+static int gettarget(fd_t** targ, dirnode_t** targnode, int ifd, proc_t* proc){
+	
+	if(ifd != AT_FDCWD){
+		
+		int err = fd_access(&proc->fdtable, targ, ifd);
+
+		if(err)
+			return err;
+		
+		
+		if(GETTYPE((*targ)->mode) != TYPE_DIR)
+			return ENOTDIR;
+		
+
+		*targnode = (*targ)->node;
+	}
+	else
+		*targnode = proc->cwd;
+
+}
+
+
+// flags is ignored for now
+
+syscallret syscall_linkat(int srcdirfd, const char* srcpath, int tgtdirfd, const char* tgtpath, int flags){
+	
+	syscallret retv;
+	retv.ret = -1;
+	
+	
+	if(srcpath > USER_SPACE_END || tgtpath > USER_SPACE_END){
+		retv.errno = EFAULT;
+		return retv;
+	}
+	
+	size_t srclen = strlen(srcpath);
+	size_t tgtlen = strlen(tgtpath);
+	
+	char srcbuff[srclen+1];
+	char tgtbuff[tgtlen+1];
+
+	strcpy(srcbuff, srcpath);
+	strcpy(tgtbuff, tgtpath);
+
+	proc_t* proc = arch_getcls()->thread->proc;
+
+
+	dirnode_t* source;
+	fd_t* srcfd = NULL;
+	dirnode_t* target;
+	fd_t* tgtfd = NULL;
+	
+	retv.errno = gettarget(&srcfd, &source, srcdirfd, proc);
+
+	if(retv.errno)
+		goto _fail;
+
+	retv.errno = gettarget(&tgtfd, &target, tgtdirfd, proc);
+
+	if(retv.errno)
+		goto _fail;
+
+	vnode_t* node;
+	
+	retv.errno = vfs_open(&node, srcbuff[0] == '/' ? proc->root : source, srcbuff);
+
+	if(retv.errno)
+		goto _fail;
+
+	retv.errno = vfs_link(tgtbuff[0] == '/' ? proc->root : target, node, tgtbuff);
+
+	vfs_close(node);
+
+	_fail:
+
+	if(srcdirfd != AT_FDCWD && srcfd)
+		fd_release(srcfd);
+
+	if(tgtdirfd != AT_FDCWD && tgtfd)
+		fd_release(tgtfd);
+
+	retv.ret = retv.errno ? -1 : 0;
+	
+	return retv;
+
+}