1 files changed, 119 insertions, 0 deletions
diff --git a/src/test/gprof-helper.c b/src/test/gprof-helper.c
new file mode 100644
index 000000000..a64c406ec
--- /dev/null
+++ b/src/test/gprof-helper.c
@@ -0,0 +1,119 @@
+/* gprof-helper.c -- preload library to profile pthread-enabled programs
+ *
+ * Authors: Sam Hocevar <sam at zoy dot org>
+ *          Daniel Jönsson <danieljo at fagotten dot org>
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the Do What The Fuck You Want To
+ *  Public License as published by Banlu Kemiyatorn. See
+ *  http://sam.zoy.org/projects/COPYING.WTFPL for more details.
+ *
+ * Compilation example:
+ * gcc -shared -fPIC gprof-helper.c -o gprof-helper.so -lpthread -ldl
+ *
+ * Usage example:
+ * LD_PRELOAD=./gprof-helper.so your_program
+ */
+
+#include <sys/time.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <dlfcn.h>
+#include <pthread.h>
+
+static void * wrapper_routine(void *);
+
+/* Original pthread function */
+static int (*pthread_create_orig)(pthread_t *__restrict,
+                                  __const pthread_attr_t *__restrict,
+                                  void *(*)(void *),
+                                  void *__restrict) = NULL;
+
+/* Library initialization function */
+void wooinit(void) __attribute__((constructor));
+
+void wooinit(void)
+{
+    pthread_create_orig = dlsym(RTLD_NEXT, "pthread_create");
+    fprintf(stderr, "pthreads: using profiling hooks for gprof\n");
+    if(pthread_create_orig == NULL)
+    {
+        char *error = dlerror();
+        if(error == NULL)
+        {
+            error = "pthread_create is NULL";
+        }
+        fprintf(stderr, "%s\n", error);
+        exit(EXIT_FAILURE);
+    }
+}
+
+/* Our data structure passed to the wrapper */
+typedef struct wrapper_s
+{
+    void * (*start_routine)(void *);
+    void * arg;
+
+    pthread_mutex_t lock;
+    pthread_cond_t  wait;
+
+    struct itimerval itimer;
+
+} wrapper_t;
+
+/* The wrapper function in charge for setting the itimer value */
+static void * wrapper_routine(void * data)
+{
+    /* Put user data in thread-local variables */
+    void * (*start_routine)(void *) = ((wrapper_t*)data)->start_routine;
+    void * arg = ((wrapper_t*)data)->arg;
+
+    /* Set the profile timer value */
+    setitimer(ITIMER_PROF, &((wrapper_t*)data)->itimer, NULL);
+
+    /* Tell the calling thread that we don't need its data anymore */
+    pthread_mutex_lock(&((wrapper_t*)data)->lock);
+    pthread_cond_signal(&((wrapper_t*)data)->wait);
+    pthread_mutex_unlock(&((wrapper_t*)data)->lock);
+
+    /* Call the real function */
+    return start_routine(arg);
+}
+
+/* Our wrapper function for the real pthread_create() */
+int pthread_create(pthread_t *__restrict thread,
+                   __const pthread_attr_t *__restrict attr,
+                   void * (*start_routine)(void *),
+                   void *__restrict arg)
+{
+    wrapper_t wrapper_data;
+    int i_return;
+
+    /* Initialize the wrapper structure */
+    wrapper_data.start_routine = start_routine;
+    wrapper_data.arg = arg;
+    getitimer(ITIMER_PROF, &wrapper_data.itimer);
+    pthread_cond_init(&wrapper_data.wait, NULL);
+    pthread_mutex_init(&wrapper_data.lock, NULL);
+    pthread_mutex_lock(&wrapper_data.lock);
+
+    /* The real pthread_create call */
+    i_return = pthread_create_orig(thread,
+                                   attr,
+                                   &wrapper_routine,
+                                   &wrapper_data);
+
+    /* If the thread was successfully spawned, wait for the data
+     * to be released */
+    if(i_return == 0)
+    {
+        pthread_cond_wait(&wrapper_data.wait, &wrapper_data.lock);
+    }
+
+    pthread_mutex_unlock(&wrapper_data.lock);
+    pthread_mutex_destroy(&wrapper_data.lock);
+    pthread_cond_destroy(&wrapper_data.wait);
+
+    return i_return;
+}
+