Introduce helper functions for safe fork+exec of processes
In some situations, we want to execute an external shell command
in a non-blocking way. Similar to 'system', but without waiting for
the child to complete. We also want to close all file descriptors
ahead of the exec() and filter + modify the environment.
Change-Id: Ib24ac8a083db32e55402ce496a5eabd8749cc888
Related: OS#4332
diff --git a/tests/exec/exec_test.c b/tests/exec/exec_test.c
new file mode 100644
index 0000000..5f4b460
--- /dev/null
+++ b/tests/exec/exec_test.c
@@ -0,0 +1,155 @@
+#include <osmocom/core/utils.h>
+#include <osmocom/core/exec.h>
+
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <unistd.h>
+#include <errno.h>
+
+static void env_dump(char **env)
+{
+ char **ent;
+
+ for (ent = env; *ent; ent++)
+ printf("\t%s\n", *ent);
+}
+
+static void test_env_filter(void)
+{
+ char *out[256];
+ char *env_in[] = {
+ "FOO=1",
+ "BAR=2",
+ "USER=mahlzeit",
+ "BAZ=3",
+ "SHELL=/bin/sh",
+ NULL
+ };
+ const char *filter[] = {
+ "SHELL",
+ "USER",
+ NULL
+ };
+ int rc;
+
+ printf("\n==== osmo_environment_filter ====\n");
+
+ printf("Input Environment:\n");
+ env_dump(env_in);
+ printf("Input Whitelist:\n");
+ env_dump((char **) filter);
+ rc = osmo_environment_filter(out, ARRAY_SIZE(out), env_in, filter);
+ printf("Output Environment (%d):\n", rc);
+ env_dump(out);
+ OSMO_ASSERT(rc == 3);
+
+ printf("Testing for NULL out\n");
+ rc = osmo_environment_filter(NULL, 123, env_in, filter);
+ OSMO_ASSERT(rc < 0);
+
+ printf("Testing for zero-length out\n");
+ rc = osmo_environment_filter(out, 0, env_in, filter);
+ OSMO_ASSERT(rc < 0);
+
+ printf("Testing for one-length out\n");
+ rc = osmo_environment_filter(out, 1, env_in, filter);
+ OSMO_ASSERT(rc == 1 && out[0] == NULL);
+
+ printf("Testing for no filter\n");
+ rc = osmo_environment_filter(out, ARRAY_SIZE(out), env_in, NULL);
+ OSMO_ASSERT(rc < 0);
+
+ printf("Testing for no input\n");
+ rc = osmo_environment_filter(out, ARRAY_SIZE(out), NULL, filter);
+ OSMO_ASSERT(rc == 1 && out[0] == NULL);
+ printf("Success!\n");
+}
+
+static void test_env_append(void)
+{
+ char *out[256] = {
+ "FOO=a",
+ "BAR=b",
+ "BAZ=c",
+ NULL,
+ };
+ char *add[] = {
+ "MAHL=zeit",
+ "GSM=global",
+ "UMTS=universal",
+ "LTE=evolved",
+ NULL,
+ };
+ int rc;
+
+ printf("\n==== osmo_environment_append ====\n");
+
+ printf("Input Environment:\n");
+ env_dump(out);
+ printf("Input Addition:\n");
+ env_dump(add);
+ rc = osmo_environment_append(out, ARRAY_SIZE(out), add);
+ printf("Output Environment (%d)\n", rc);
+ env_dump(out);
+ OSMO_ASSERT(rc == 8);
+ printf("Success!\n");
+}
+
+static void test_close_fd(void)
+{
+ struct stat st;
+ int fds[2];
+ int rc;
+
+ printf("\n==== osmo_close_all_fds_above ====\n");
+
+ /* create some extra fds */
+ rc = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
+ OSMO_ASSERT(rc == 0);
+
+ rc = fstat(fds[0], &st);
+ OSMO_ASSERT(rc == 0);
+
+ osmo_close_all_fds_above(2);
+
+ rc = fstat(fds[0], &st);
+ OSMO_ASSERT(rc == -1 && errno == EBADF);
+ rc = fstat(fds[1], &st);
+ OSMO_ASSERT(rc == -1 && errno == EBADF);
+ printf("Success!\n");
+}
+
+static void test_system_nowait(void)
+{
+ char *addl_env[] = {
+ "MAHLZEIT=spaet",
+ NULL
+ };
+ int rc, pid, i;
+
+ printf("\n==== osmo_system_nowait ====\n");
+
+ pid = osmo_system_nowait("env | grep MAHLZEIT 1>&2", osmo_environment_whitelist, addl_env);
+ OSMO_ASSERT(pid > 0);
+ for (i = 0; i < 10; i++) {
+ sleep(1);
+ rc = waitpid(pid, NULL, WNOHANG);
+ if (rc == pid) {
+ printf("Success!\n");
+ return;
+ }
+ }
+ printf("ERROR: child didn't terminate within 10s\n");
+}
+
+int main(int argc, char **argv)
+{
+ test_env_filter();
+ test_env_append();
+ test_close_fd();
+ test_system_nowait();
+
+ exit(0);
+}