From d9757dcf974045310b8d106112cf86f826b151f9 Mon Sep 17 00:00:00 2001
From: Hariharan Devarajan <mani.hariharan@gmail.com>
Date: Mon, 30 Sep 2024 14:03:10 -0700
Subject: [PATCH] Bugfix: Fix for handle AT_FDCWD for readlinkat (#209)

* check for fd < 0

* fixed readlinkat to handle AT_FDCWD
---
 src/dftracer/brahma/posix.cpp | 20 +++++++++++++++-----
 src/dftracer/brahma/posix.h   |  2 +-
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/src/dftracer/brahma/posix.cpp b/src/dftracer/brahma/posix.cpp
index 587ff3e..18f4b01 100644
--- a/src/dftracer/brahma/posix.cpp
+++ b/src/dftracer/brahma/posix.cpp
@@ -382,11 +382,21 @@ ssize_t brahma::POSIXDFTracer::readlink(const char *path, char *buf,
 ssize_t brahma::POSIXDFTracer::readlinkat(int fd, const char *path, char *buf,
                                           size_t bufsize) {
   BRAHMA_MAP_OR_FAIL(readlinkat);
-  DFT_LOGGER_START(fd);
-  DFT_LOGGER_UPDATE(fd);
-  DFT_LOGGER_UPDATE(bufsize);
-  ssize_t ret = __real_readlinkat(fd, path, buf, bufsize);
-  DFT_LOGGER_END();
+  ssize_t ret;
+  if (fd != AT_FDCWD) {
+    DFT_LOGGER_START(fd);
+    DFT_LOGGER_UPDATE(fd);
+    DFT_LOGGER_UPDATE(path);
+    DFT_LOGGER_UPDATE(bufsize);
+    ret = __real_readlinkat(fd, path, buf, bufsize);
+    DFT_LOGGER_END();
+  } else {
+    DFT_LOGGER_START(path);
+    DFT_LOGGER_UPDATE(fd);
+    DFT_LOGGER_UPDATE(bufsize);
+    ret = __real_readlinkat(fd, path, buf, bufsize);
+    DFT_LOGGER_END();
+  }
   return ret;
 }
 
diff --git a/src/dftracer/brahma/posix.h b/src/dftracer/brahma/posix.h
index 01ce95f..df6a869 100644
--- a/src/dftracer/brahma/posix.h
+++ b/src/dftracer/brahma/posix.h
@@ -30,7 +30,7 @@ class POSIXDFTracer : public POSIX {
   bool trace_all_files;
 
   inline uint16_t is_traced(int fd, const char *func) {
-    if (fd == -1) return 0;
+    if (fd < 0) return 0;
     uint16_t trace = tracked_fd[fd % MAX_FD];
     if (trace != 0) {
       DFTRACER_LOG_DEBUG(