Re: [PATCH] tests/qtest/migration-test: Use g_autofree to avoid leaks on error paths

[Dr. David Alan Gilbert]

* Peter Maydell (peter.maydell@linaro.org) wrote:
> Coverity notices that several places in the migration-test code fail
> to free memory in error-exit paths.  This is pretty unimportant in
> test case code, but we can avoid having to manually free the memory
> entirely by using g_autofree.
> 
> The places where Coverity spotted a leak were relating to early exits
> not freeing 'uri' in test_precopy_unix(), do_test_validate_uuid(),
> migrate_postcopy_prepare() and test_migrate_auto_converge().  This
> patch converts all the string-allocation in the test code to
> g_autofree for consistency.
> 
> Fixes: Coverity CID 1432313, 1432315, 1432352, 1432364
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> ---
>  tests/qtest/migration-test.c | 61 ++++++++++++------------------------
>  1 file changed, 20 insertions(+), 41 deletions(-)
> 
> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> index 3a711bb4929..a0c9b72b951 100644
> --- a/tests/qtest/migration-test.c
> +++ b/tests/qtest/migration-test.c
> @@ -110,13 +110,12 @@ static void init_bootfile(const char *bootpath, void 
> *content, size_t len)
>   */
>  static void wait_for_serial(const char *side)
>  {
> -    char *serialpath = g_strdup_printf("%s/%s", tmpfs, side);
> +    g_autofree char *serialpath = g_strdup_printf("%s/%s", tmpfs, side);
>      FILE *serialfile = fopen(serialpath, "r");
>      const char *arch = qtest_get_arch();
>      int started = (strcmp(side, "src_serial") == 0 &&
>                     strcmp(arch, "ppc64") == 0) ? 0 : 1;
>  
> -    g_free(serialpath);
>      do {
>          int readvalue = fgetc(serialfile);
>  
> @@ -274,10 +273,9 @@ static void check_guests_ram(QTestState *who)
>  
>  static void cleanup(const char *filename)
>  {
> -    char *path = g_strdup_printf("%s/%s", tmpfs, filename);
> +    g_autofree char *path = g_strdup_printf("%s/%s", tmpfs, filename);
>  
>      unlink(path);
> -    g_free(path);
>  }
>  
>  static char *SocketAddress_to_str(SocketAddress *addr)
> @@ -374,11 +372,8 @@ static char *migrate_get_parameter_str(QTestState *who,
>  static void migrate_check_parameter_str(QTestState *who, const char 
> *parameter,
>                                          const char *value)
>  {
> -    char *result;
> -
> -    result = migrate_get_parameter_str(who, parameter);
> +    g_autofree char *result = migrate_get_parameter_str(who, parameter);
>      g_assert_cmpstr(result, ==, value);
> -    g_free(result);
>  }
>  
>  static void migrate_set_parameter_str(QTestState *who, const char *parameter,
> @@ -495,12 +490,14 @@ static void migrate_start_destroy(MigrateStart *args)
>  static int test_migrate_start(QTestState **from, QTestState **to,
>                                const char *uri, MigrateStart *args)
>  {
> -    gchar *arch_source, *arch_target;
> -    gchar *cmd_source, *cmd_target;
> +    g_autofree gchar *arch_source = NULL;
> +    g_autofree gchar *arch_target = NULL;
> +    g_autofree gchar *cmd_source = NULL;
> +    g_autofree gchar *cmd_target = NULL;
>      const gchar *ignore_stderr;
> -    char *bootpath = NULL;
> -    char *shmem_opts;
> -    char *shmem_path;
> +    g_autofree char *bootpath = NULL;
> +    g_autofree char *shmem_opts = NULL;
> +    g_autofree char *shmem_path = NULL;
>      const char *arch = qtest_get_arch();
>      const char *machine_opts = NULL;
>      const char *memory_size;
> @@ -559,8 +556,6 @@ static int test_migrate_start(QTestState **from, 
> QTestState **to,
>          g_assert_not_reached();
>      }
>  
> -    g_free(bootpath);
> -
>      if (!getenv("QTEST_LOG") && args->hide_stderr) {
>          ignore_stderr = "2>/dev/null";
>      } else {
> @@ -588,11 +583,9 @@ static int test_migrate_start(QTestState **from, 
> QTestState **to,
>                                   memory_size, tmpfs,
>                                   arch_source, shmem_opts, args->opts_source,
>                                   ignore_stderr);
> -    g_free(arch_source);
>      if (!args->only_target) {
>          *from = qtest_init(cmd_source);
>      }
> -    g_free(cmd_source);
>  
>      cmd_target = g_strdup_printf("-accel kvm -accel tcg%s%s "
>                                   "-name target,debug-threads=on "
> @@ -605,18 +598,14 @@ static int test_migrate_start(QTestState **from, 
> QTestState **to,
>                                   memory_size, tmpfs, uri,
>                                   arch_target, shmem_opts,
>                                   args->opts_target, ignore_stderr);
> -    g_free(arch_target);
>      *to = qtest_init(cmd_target);
> -    g_free(cmd_target);
>  
> -    g_free(shmem_opts);
>      /*
>       * Remove shmem file immediately to avoid memory leak in test failed 
> case.
>       * It's valid becase QEMU has already opened this file
>       */
>      if (args->use_shmem) {
>          unlink(shmem_path);
> -        g_free(shmem_path);
>      }
>  
>  out:
> @@ -662,7 +651,7 @@ static int migrate_postcopy_prepare(QTestState **from_ptr,
>                                      QTestState **to_ptr,
>                                      MigrateStart *args)
>  {
> -    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>      QTestState *from, *to;
>  
>      if (test_migrate_start(&from, &to, uri, args)) {
> @@ -684,7 +673,6 @@ static int migrate_postcopy_prepare(QTestState **from_ptr,
>      wait_for_serial("src_serial");
>  
>      migrate_qmp(from, uri, "{}");
> -    g_free(uri);
>  
>      wait_for_migration_pass(from);
>  
> @@ -724,7 +712,7 @@ static void test_postcopy_recovery(void)
>  {
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to;
> -    char *uri;
> +    g_autofree char *uri = NULL;
>  
>      args->hide_stderr = true;
>  
> @@ -775,7 +763,6 @@ static void test_postcopy_recovery(void)
>                                (const char * []) { "failed", "active",
>                                                    "completed", NULL });
>      migrate_qmp(from, uri, "{'resume': true}");
> -    g_free(uri);
>  
>      /* Restore the postcopy bandwidth to unlimited */
>      migrate_set_parameter_int(from, "max-postcopy-bandwidth", 0);
> @@ -800,7 +787,7 @@ static void test_baddest(void)
>  
>  static void test_precopy_unix(void)
>  {
> -    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to;
>  
> @@ -836,14 +823,13 @@ static void test_precopy_unix(void)
>      wait_for_migration_complete(from);
>  
>      test_migrate_end(from, to, true);
> -    g_free(uri);
>  }
>  
>  #if 0
>  /* Currently upset on aarch64 TCG */
>  static void test_ignore_shared(void)
>  {
> -    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>      QTestState *from, *to;
>  
>      if (test_migrate_start(&from, &to, uri, false, true, NULL, NULL)) {
> @@ -873,7 +859,6 @@ static void test_ignore_shared(void)
>      g_assert_cmpint(read_ram_property_int(from, "transferred"), <, 1024 * 
> 1024);
>  
>      test_migrate_end(from, to, true);
> -    g_free(uri);
>  }
>  #endif
>  
> @@ -925,16 +910,15 @@ static void test_xbzrle(const char *uri)
>  
>  static void test_xbzrle_unix(void)
>  {
> -    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>  
>      test_xbzrle(uri);
> -    g_free(uri);
>  }
>  
>  static void test_precopy_tcp(void)
>  {
>      MigrateStart *args = migrate_start_new();
> -    char *uri;
> +    g_autofree char *uri = NULL;
>      QTestState *from, *to;
>  
>      if (test_migrate_start(&from, &to, "tcp:127.0.0.1:0", args)) {
> @@ -971,7 +955,6 @@ static void test_precopy_tcp(void)
>      wait_for_migration_complete(from);
>  
>      test_migrate_end(from, to, true);
> -    g_free(uri);
>  }
>  
>  static void test_migrate_fd_proto(void)
> @@ -1060,7 +1043,7 @@ static void test_migrate_fd_proto(void)
>  
>  static void do_test_validate_uuid(MigrateStart *args, bool should_fail)
>  {
> -    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>      QTestState *from, *to;
>  
>      if (test_migrate_start(&from, &to, uri, args)) {
> @@ -1088,7 +1071,6 @@ static void do_test_validate_uuid(MigrateStart *args, 
> bool should_fail)
>      }
>  
>      test_migrate_end(from, to, false);
> -    g_free(uri);
>  }
>  
>  static void test_validate_uuid(void)
> @@ -1136,7 +1118,7 @@ static void test_validate_uuid_dst_not_set(void)
>  
>  static void test_migrate_auto_converge(void)
>  {
> -    char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
> +    g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to;
>      int64_t remaining, percentage;
> @@ -1214,7 +1196,6 @@ static void test_migrate_auto_converge(void)
>      wait_for_serial("dest_serial");
>      wait_for_migration_complete(from);
>  
> -    g_free(uri);
>  
>      test_migrate_end(from, to, true);
>  }
> @@ -1224,7 +1205,7 @@ static void test_multifd_tcp(const char *method)
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to;
>      QDict *rsp;
> -    char *uri;
> +    g_autofree char *uri = NULL;
>  
>      if (test_migrate_start(&from, &to, "defer", args)) {
>          return;
> @@ -1273,7 +1254,6 @@ static void test_multifd_tcp(const char *method)
>      wait_for_serial("dest_serial");
>      wait_for_migration_complete(from);
>      test_migrate_end(from, to, true);
> -    g_free(uri);
>  }
>  
>  static void test_multifd_tcp_none(void)
> @@ -1309,7 +1289,7 @@ static void test_multifd_tcp_cancel(void)
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to, *to2;
>      QDict *rsp;
> -    char *uri;
> +    g_autofree char *uri = NULL;
>  
>      args->hide_stderr = true;
>  
> @@ -1387,7 +1367,6 @@ static void test_multifd_tcp_cancel(void)
>      wait_for_serial("dest_serial");
>      wait_for_migration_complete(from);
>      test_migrate_end(from, to2, true);
> -    g_free(uri);
>  }
>  
>  int main(int argc, char **argv)
> -- 
> 2.20.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK