Kernel+LibC+LibCore: Implement `symlinkat(2)`

Co-Authored-By: Daniel Bertalan <dani@danielbertalan.dev>

5 files changed, 11 insertions, 2 deletions

diff --git a/Kernel/API/Syscall.h b/Kernel/API/Syscall.h
index f306e549b1..cd58e676bb 100644
--- a/Kernel/API/Syscall.h
+++ b/Kernel/API/Syscall.h
@@ -413,6 +413,7 @@ struct SC_mknod_params {
 struct SC_symlink_params {
     StringArgument target;
     StringArgument linkpath;
+    int dirfd;
 };
 
 struct SC_rename_params {
diff --git a/Kernel/Syscalls/link.cpp b/Kernel/Syscalls/link.cpp
index 5cc048caa8..a94f02ac2f 100644
--- a/Kernel/Syscalls/link.cpp
+++ b/Kernel/Syscalls/link.cpp
@@ -29,7 +29,7 @@ ErrorOr<FlatPtr> Process::sys$symlink(Userspace<Syscall::SC_symlink_params const
 
     auto target = TRY(get_syscall_path_argument(params.target));
     auto linkpath = TRY(get_syscall_path_argument(params.linkpath));
-    TRY(VirtualFileSystem::the().symlink(credentials(), target->view(), linkpath->view(), current_directory()));
+    TRY(VirtualFileSystem::the().symlink(credentials(), target->view(), linkpath->view(), TRY(custody_for_dirfd(params.dirfd))));
     return 0;
 }
 
diff --git a/Userland/Libraries/LibC/unistd.cpp b/Userland/Libraries/LibC/unistd.cpp
index e3fbca0e9f..8e732f197a 100644
--- a/Userland/Libraries/LibC/unistd.cpp
+++ b/Userland/Libraries/LibC/unistd.cpp
@@ -673,11 +673,17 @@ int unlinkat(int dirfd, char const* pathname, int flags)
 // https://pubs.opengroup.org/onlinepubs/9699919799/functions/symlink.html
 int symlink(char const* target, char const* linkpath)
 {
+    return symlinkat(target, AT_FDCWD, linkpath);
+}
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/symlinkat.html
+int symlinkat(char const* target, int newdirfd, char const* linkpath)
+{
     if (!target || !linkpath) {
         errno = EFAULT;
         return -1;
     }
-    Syscall::SC_symlink_params params { { target, strlen(target) }, { linkpath, strlen(linkpath) } };
+    Syscall::SC_symlink_params params { { target, strlen(target) }, { linkpath, strlen(linkpath) }, newdirfd };
     int rc = syscall(SC_symlink, &params);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
diff --git a/Userland/Libraries/LibC/unistd.h b/Userland/Libraries/LibC/unistd.h
index ee4bf2f1ae..ef8c28ad47 100644
--- a/Userland/Libraries/LibC/unistd.h
+++ b/Userland/Libraries/LibC/unistd.h
@@ -95,6 +95,7 @@ int link(char const* oldpath, char const* newpath);
 int unlink(char const* pathname);
 int unlinkat(int dirfd, char const* pathname, int flags);
 int symlink(char const* target, char const* linkpath);
+int symlinkat(char const* target, int newdirfd, char const* linkpath);
 int rmdir(char const* pathname);
 int dup(int old_fd);
 int dup2(int old_fd, int new_fd);
diff --git a/Userland/Libraries/LibCore/System.cpp b/Userland/Libraries/LibCore/System.cpp
index 2970c23dfe..f58b4952b7 100644
--- a/Userland/Libraries/LibCore/System.cpp
+++ b/Userland/Libraries/LibCore/System.cpp
@@ -839,6 +839,7 @@ ErrorOr<void> symlink(StringView target, StringView link_path)
     Syscall::SC_symlink_params params {
         .target = { target.characters_without_null_termination(), target.length() },
         .linkpath = { link_path.characters_without_null_termination(), link_path.length() },
+        .dirfd = AT_FDCWD,
     };
     int rc = syscall(SC_symlink, &params);
     HANDLE_SYSCALL_RETURN_VALUE("symlink", rc, {});