Fix segmentation fault when using jq in threads

src/jq_test.c

@@ -2,12 +2,17 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#ifdef HAVE_PTHREAD
+#include <pthread.h>
+#endif
 #include "jv.h"
 #include "jq.h"
 
 static void jv_test();
 static void run_jq_tests(jv, int, FILE *, int, int);
-
+#ifdef HAVE_PTHREAD
+static void run_jq_pthread_tests();
+#endif
 
 int jq_testsuite(jv libdirs, int verbose, int argc, char* argv[]) {
   FILE *testdata = stdin;
@@ -32,6 +37,9 @@ int jq_testsuite(jv libdirs, int verbose, int argc, char* argv[]) {
     }
   }
   run_jq_tests(libdirs, verbose, testdata, skip, take);
+#ifdef HAVE_PTHREAD
+  run_jq_pthread_tests();
+#endif
   return 0;
 }
 
@@ -105,7 +113,7 @@ static void run_jq_tests(jv lib_dirs, int verbose, FILE *testdata, int skip, int
         if (buf[0] == '\n' || (buf[0] == '\r' && buf[1] == '\n'))
           break;
       }
-      
+
       must_fail = 0;
       check_msg = 0;
 
@@ -229,7 +237,7 @@ static void run_jq_tests(jv lib_dirs, int verbose, FILE *testdata, int skip, int
     total_skipped = tests_to_skip - skip;
   }
 
-  printf("%d of %d tests passed (%d malformed, %d skipped)\n", 
+  printf("%d of %d tests passed (%d malformed, %d skipped)\n",
     passed, tests, invalid, total_skipped);
 
   if (skip > 0) {
@@ -241,6 +249,88 @@ static void run_jq_tests(jv lib_dirs, int verbose, FILE *testdata, int skip, int
 }
 
 
+/// pthread regression test
+#ifdef HAVE_PTHREAD
+#define NUMBER_OF_THREADS 3
+struct test_pthread_data {
+    int result;
+};
+
+static int test_pthread_jq_parse(jq_state *jq, struct jv_parser *parser)
+{
+    int rv = 0;
+    jv value;
+
+    value = jv_parser_next(parser);
+    while (jv_is_valid(value)) {
+        jq_start(jq, value, 0);
+        jv result = jq_next(jq);
+
+        while (jv_is_valid(result)) {
+            jv_free(result);
+            result = jq_next(jq);
+        }
+        jv_free(result);
+        value = jv_parser_next(parser);
+    }
+    jv_free(value);
+    return rv;
+}
+
+static void *test_pthread_run(void *ptr) {
+    int rv;
+    jq_state *jq;
+    const char *prg = ".data";
+    const char *buf = "{ \"data\": 1 }";
+    struct test_pthread_data *data = ptr;
+
+    jq = jq_init();
+    if (jq_compile(jq, prg) == 0) {
+        jq_teardown(&jq);
+        return NULL;
+    }
+
+    struct jv_parser *parser = jv_parser_new(0);
+    jv_parser_set_buf(parser, buf, strlen(buf), 0);
+    rv = test_pthread_jq_parse(jq, parser);
+
+    data->result = rv;
+
+    jv_parser_free(parser);
+    jq_teardown(&jq);
+    return NULL;
+}
+
+static void run_jq_pthread_tests() {
+    pthread_t threads[NUMBER_OF_THREADS];
+    struct test_pthread_data data[NUMBER_OF_THREADS];
+    int createerror;
+    int a;
+
+    memset(&threads, 0, sizeof(threads));
+    memset(&data, 0, sizeof(data));
+
+    // Create all threads
+    for (a = 0; a < NUMBER_OF_THREADS; ++a) {
+        createerror = pthread_create(&threads[a], NULL, test_pthread_run, &data[a]);
+        assert(createerror == 0);
+    }
+
+    // wait for all threads
+    for(a = 0; a < NUMBER_OF_THREADS; ++a) {
+        if (threads[a] != 0) {
+            pthread_join(threads[a], NULL);
+        }
+    }
+
+    // check results
+    for(a = 0; a < NUMBER_OF_THREADS; ++a) {
+        assert(data[a].result == 0);
+    }
+}
+#endif // HAVE_PTHREAD
+
+
 static void jv_test() {
   /// JSON parser regression tests
   {

src/jv_alloc.c

@@ -45,9 +45,11 @@ static void memory_exhausted() {
 #ifdef HAVE_PTHREAD_KEY_CREATE
 #include <pthread.h>
 
-pthread_key_t nomem_handler_key;
-pthread_once_t mem_once = PTHREAD_ONCE_INIT;
+static pthread_key_t nomem_handler_key;
+static pthread_once_t mem_once = PTHREAD_ONCE_INIT;
 
+/* tsd_fini is called on application exit */
+/* it clears the nomem_handler allocated in the main thread */
 static void tsd_fini(void) {
   struct nomem_handler *nomem_handler;
   nomem_handler = pthread_getspecific(nomem_handler_key);
@@ -57,24 +59,39 @@ static void tsd_fini(void) {
   }
 }
 
+/* The tsd_fini_thread is a destructor set by calling */
+/* pthread_key_create(&nomem_handler_key, tsd_fini_thread) */
+/* It is called when thread ends */
+static void tsd_fini_thread(void *nomem_handler) {
+  free(nomem_handler);
+}
+
 static void tsd_init(void) {
-  if (pthread_key_create(&nomem_handler_key, NULL) != 0) {
+  if (pthread_key_create(&nomem_handler_key, tsd_fini_thread) != 0) {
     fprintf(stderr, "jq: error: cannot create thread specific key");
     abort();
   }
   if (atexit(tsd_fini) != 0) {
     fprintf(stderr, "jq: error: cannot set an exit handler");
     abort();
   }
-  struct nomem_handler *nomem_handler = calloc(1, sizeof(struct nomem_handler));
-  if (pthread_setspecific(nomem_handler_key, nomem_handler) != 0) {
-    fprintf(stderr, "jq: error: cannot set thread specific data");
-    abort();
+}
+
+static void tsd_init_nomem_handler(void)
+{
+  if (pthread_getspecific(nomem_handler_key) == NULL) {
+    struct nomem_handler *nomem_handler = calloc(1, sizeof(struct nomem_handler));
+    if (pthread_setspecific(nomem_handler_key, nomem_handler) != 0) {
+      fprintf(stderr, "jq: error: cannot set thread specific data");
+      abort();
+    }
   }
 }
 
 void jv_nomem_handler(jv_nomem_handler_f handler, void *data) {
   pthread_once(&mem_once, tsd_init); // cannot fail
+  tsd_init_nomem_handler();
+
   struct nomem_handler *nomem_handler;
 
   nomem_handler = pthread_getspecific(nomem_handler_key);
@@ -91,6 +108,8 @@ static void memory_exhausted() {
   struct nomem_handler *nomem_handler;
 
   pthread_once(&mem_once, tsd_init);
+  tsd_init_nomem_handler();
+
   nomem_handler = pthread_getspecific(nomem_handler_key);
   if (nomem_handler)
     nomem_handler->handler(nomem_handler->data); // Maybe handler() will longjmp() to safety