Fix: liblttng-ust-fd.so: override fclose symbol

[lttng-ust.git] / liblttng-ust-comm / lttng-ust-fd-tracker.c

diff --git a/liblttng-ust-comm/lttng-ust-fd-tracker.c b/liblttng-ust-comm/lttng-ust-fd-tracker.c
index 5a763ff2960550c094306d9d7d90de3d2bf9d037..d56288e370470e1deb94a25dc5603048c75f03aa 100644 (file)
--- a/liblttng-ust-comm/lttng-ust-fd-tracker.c
+++ b/liblttng-ust-comm/lttng-ust-fd-tracker.c
@@ -197,6 +197,38 @@ int lttng_ust_safe_close_fd(int fd, int (*close_cb)(int fd))
        return ret;
 }
 
+/*
+ * Interface allowing applications to close arbitrary streams.
+ * We check if it is owned by lttng-ust, and return -1, errno=EBADF
+ * instead of closing it if it is the case.
+ */
+int lttng_ust_safe_fclose_stream(FILE *stream, int (*fclose_cb)(FILE *stream))
+{
+       int ret = 0, fd;
+
+       lttng_ust_fixup_fd_tracker_tls();
+
+       /*
+        * If called from lttng-ust, we directly call fclose without
+        * validating whether the FD is part of the tracked set.
+        */
+       if (URCU_TLS(thread_fd_tracking))
+               return fclose_cb(stream);
+
+       fd = fileno(stream);
+
+       lttng_ust_lock_fd_tracker();
+       if (IS_FD_VALID(fd) && IS_FD_SET(fd, lttng_fd_set)) {
+               ret = -1;
+               errno = EBADF;
+       } else {
+               ret = fclose_cb(stream);
+       }
+       lttng_ust_unlock_fd_tracker();
+
+       return ret;
+}
+
 #ifdef __OpenBSD__
 static void set_close_success(int *p)
 {