Tests: Add test app to generate syscalls

[lttng-tools.git] / tests / utils / testapp / gen-syscall-events / gen-syscall-events.c

diff --git a/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c b/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c
new file mode 100644 (file)
index 0000000..5e4aabe
--- /dev/null
+++ b/tests/utils/testapp/gen-syscall-events/gen-syscall-events.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) - 2017 Francis Deslauriers <francis.deslauriers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#define _LGPL_SOURCE
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+#include "utils.h"
+
+#define MAX_LEN 16
+/*
+ * The process waits for the creation of a file passed as argument from an
+ * external processes to execute a syscall and exiting. This is useful for tests
+ * in combinaison with LTTng's PID tracker feature where we can trace the kernel
+ * events generated by our test process only.
+ */
+int main(int argc, char **argv)
+{
+       int fd, ret = 0;
+       char buf[MAX_LEN];
+       char *start_file;
+
+       if (argc != 2) {
+               fprintf(stderr, "Error: Missing argument\n");
+               fprintf(stderr, "USAGE: %s PATH_WAIT_FILE\n", argv[0]);
+               ret = -1;
+               goto error;
+       }
+
+       start_file = argv[1];
+
+       /*
+        * Wait for the start_file to be created by an external process
+        * (typically the test script) before executing the syscalls.
+        */
+       ret = wait_on_file(start_file);
+       if (ret != 0) {
+               goto error;
+       }
+
+       /*
+        * Start generating syscalls. We use syscall(2) to prevent libc to change
+        * the underlying syscall. e.g. calling openat(2) instead of open(2).
+        */
+       fd = syscall(SYS_open, "/proc/cpuinfo", O_RDONLY);
+       if (fd < 0) {
+               perror("open");
+               ret = -1;
+               goto error;
+       }
+
+       ret = syscall(SYS_read, fd, buf, MAX_LEN);
+       if (ret < 0) {
+               perror("read");
+               ret = -1;
+               goto error;
+       }
+
+       ret = syscall(SYS_close, fd);
+       if (ret == -1) {
+               perror("close");
+               ret = -1;
+               goto error;
+       }
+
+error:
+       return ret;
+}