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

Now with the ability to specify different bases for the old and new
paths.

3 files changed, 10 insertions, 1 deletions

diff --git a/Userland/Libraries/LibC/stdio.cpp b/Userland/Libraries/LibC/stdio.cpp
index e73c64c856..ed34dd8101 100644
--- a/Userland/Libraries/LibC/stdio.cpp
+++ b/Userland/Libraries/LibC/stdio.cpp
@@ -1126,11 +1126,17 @@ int fclose(FILE* stream)
 // https://pubs.opengroup.org/onlinepubs/9699919799/functions/rename.html
 int rename(char const* oldpath, char const* newpath)
 {
+    return renameat(AT_FDCWD, oldpath, AT_FDCWD, newpath);
+}
+
+// https://pubs.opengroup.org/onlinepubs/9699919799/functions/renameat.html
+int renameat(int olddirfd, char const* oldpath, int newdirfd, char const* newpath)
+{
     if (!oldpath || !newpath) {
         errno = EFAULT;
         return -1;
     }
-    Syscall::SC_rename_params params { { oldpath, strlen(oldpath) }, { newpath, strlen(newpath) } };
+    Syscall::SC_rename_params params { olddirfd, { oldpath, strlen(oldpath) }, newdirfd, { newpath, strlen(newpath) } };
     int rc = syscall(SC_rename, &params);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }
diff --git a/Userland/Libraries/LibC/stdio.h b/Userland/Libraries/LibC/stdio.h
index 4b9a769f87..83c349f57d 100644
--- a/Userland/Libraries/LibC/stdio.h
+++ b/Userland/Libraries/LibC/stdio.h
@@ -96,6 +96,7 @@ int setvbuf(FILE*, char* buf, int mode, size_t);
 void setbuf(FILE*, char* buf);
 void setlinebuf(FILE*);
 int rename(char const* oldpath, char const* newpath);
+int renameat(int olddirfd, char const* oldpath, int newdirfd, char const* newpath);
 FILE* tmpfile(void);
 char* tmpnam(char*);
 FILE* popen(char const* command, char const* type);
diff --git a/Userland/Libraries/LibCore/System.cpp b/Userland/Libraries/LibCore/System.cpp
index 11c8ea9b02..f96519ebf4 100644
--- a/Userland/Libraries/LibCore/System.cpp
+++ b/Userland/Libraries/LibCore/System.cpp
@@ -920,7 +920,9 @@ ErrorOr<void> rename(StringView old_path, StringView new_path)
 
 #ifdef AK_OS_SERENITY
     Syscall::SC_rename_params params {
+        .olddirfd = AT_FDCWD,
         .old_path = { old_path.characters_without_null_termination(), old_path.length() },
+        .newdirfd = AT_FDCWD,
         .new_path = { new_path.characters_without_null_termination(), new_path.length() },
     };
     int rc = syscall(SC_rename, &params);