Add extra_args to exec_child()

Related:
    https://fedorahosted.org/sssd/ticket/2503

Currently all child processes use the same arguments, the construction
of argv[] is even hardcoded in exec_child(). Add an extra_args[] array
that extends the common set of argvs so that we can have child-specific
arguments. Also adds a unit test.

Reviewed-by: Sumit Bose <sbose@redhat.com>

8 files changed, 93 insertions, 22 deletions

diff --git a/src/providers/ad/ad_gpo.c b/src/providers/ad/ad_gpo.c
index 83edbe4fb..62715861c 100644
--- a/src/providers/ad/ad_gpo.c
+++ b/src/providers/ad/ad_gpo.c
@@ -3960,7 +3960,7 @@ gpo_fork_child(struct tevent_req *req)
     if (pid == 0) { /* child */
         err = exec_child(state,
                          pipefd_to_child, pipefd_from_child,
-                         GPO_CHILD, gpo_child_debug_fd);
+                         GPO_CHILD, gpo_child_debug_fd, NULL);
         DEBUG(SSSDBG_CRIT_FAILURE, "Could not exec gpo_child: [%d][%s].\n",
               err, strerror(err));
         return err;
diff --git a/src/providers/ipa/ipa_selinux.c b/src/providers/ipa/ipa_selinux.c
index 30ad6f0a7..531258dac 100644
--- a/src/providers/ipa/ipa_selinux.c
+++ b/src/providers/ipa/ipa_selinux.c
@@ -1036,7 +1036,8 @@ static errno_t selinux_fork_child(struct selinux_child_state *state)
     if (pid == 0) { /* child */
         ret = exec_child(state,
                          pipefd_to_child, pipefd_from_child,
-                         SELINUX_CHILD, selinux_child_debug_fd);
+                         SELINUX_CHILD, selinux_child_debug_fd,
+                         NULL);
         DEBUG(SSSDBG_CRIT_FAILURE, "Could not exec selinux_child: [%d][%s].\n",
               ret, sss_strerror(ret));
         return ret;
diff --git a/src/providers/krb5/krb5_child_handler.c b/src/providers/krb5/krb5_child_handler.c
index 93961172c..9bb61f654 100644
--- a/src/providers/krb5/krb5_child_handler.c
+++ b/src/providers/krb5/krb5_child_handler.c
@@ -299,7 +299,8 @@ static errno_t fork_child(struct tevent_req *req)
     if (pid == 0) { /* child */
         err = exec_child(state,
                          pipefd_to_child, pipefd_from_child,
-                         KRB5_CHILD, state->kr->krb5_ctx->child_debug_fd);
+                         KRB5_CHILD, state->kr->krb5_ctx->child_debug_fd,
+                         NULL);
         if (err != EOK) {
             DEBUG(SSSDBG_CRIT_FAILURE, "Could not exec KRB5 child: [%d][%s].\n",
                       err, strerror(err));
diff --git a/src/providers/ldap/sdap_child_helpers.c b/src/providers/ldap/sdap_child_helpers.c
index 400109890..b60891d2b 100644
--- a/src/providers/ldap/sdap_child_helpers.c
+++ b/src/providers/ldap/sdap_child_helpers.c
@@ -108,7 +108,8 @@ static errno_t sdap_fork_child(struct tevent_context *ev,
     if (pid == 0) { /* child */
         err = exec_child(child,
                          pipefd_to_child, pipefd_from_child,
-                         LDAP_CHILD, ldap_child_debug_fd);
+                         LDAP_CHILD, ldap_child_debug_fd,
+                         NULL);
         DEBUG(SSSDBG_CRIT_FAILURE, "Could not exec LDAP child: [%d][%s].\n",
                                     err, strerror(err));
         return err;
diff --git a/src/tests/cmocka/test_child.c b/src/tests/cmocka/test_child.c
index a857afce1..0bb50a4e0 100644
--- a/src/tests/cmocka/test_child.c
+++ b/src/tests/cmocka/test_child.c
@@ -35,13 +35,9 @@ int main(int argc, const char *argv[])
     int opt;
     int debug_fd = -1;
     poptContext pc;
-    const char *action;
-    ssize_t len = 0;
-    ssize_t written;
-    errno_t ret;
-    uint8_t *buf[IN_BUF_SIZE];
-    uid_t uid;
-    gid_t gid;
+    const char *action = NULL;
+    const char *guitar;
+    const char *drums;
 
     struct poptOption long_options[] = {
         POPT_AUTOHELP
@@ -54,8 +50,9 @@ int main(int argc, const char *argv[])
         {"debug-fd", 0, POPT_ARG_INT, &debug_fd, 0,
          _("An open file descriptor for the debug logs"), NULL},
         {"debug-to-stderr", 0, POPT_ARG_NONE | POPT_ARGFLAG_DOC_HIDDEN, &debug_to_stderr, 0, \
-         _("Send the debug output to stderr directly."), NULL }, \
-        SSSD_SERVER_OPTS(uid, gid)
+         _("Send the debug output to stderr directly."), NULL },
+        {"guitar", 0, POPT_ARG_STRING, &guitar, 0, _("Who plays guitar"), NULL },
+        {"drums", 0, POPT_ARG_STRING, &drums, 0, _("Who plays drums"), NULL },
         POPT_TABLEEND
     };
 
@@ -73,11 +70,17 @@ int main(int argc, const char *argv[])
         }
     }
 
-    DEBUG(SSSDBG_TRACE_FUNC, "test_child completed successfully\n");
-    _exit(0);
+    action = getenv("TEST_CHILD_ACTION");
+    if (action) {
+        if (strcasecmp(action, "check_extra_args") == 0) {
+            if (!(strcmp(guitar, "george") == 0 \
+                        && strcmp(drums, "ringo") == 0)) {
+                DEBUG(SSSDBG_CRIT_FAILURE, "This band sounds weird\n");
+                _exit(1);
+            }
+        }
+    }
 
-fail:
     DEBUG(SSSDBG_TRACE_FUNC, "test_child completed successfully\n");
-    close(STDOUT_FILENO);
-    _exit(-1);
+    _exit(0);
 }
diff --git a/src/tests/cmocka/test_child_common.c b/src/tests/cmocka/test_child_common.c
index f2cd8c008..112ed0ad9 100644
--- a/src/tests/cmocka/test_child_common.c
+++ b/src/tests/cmocka/test_child_common.c
@@ -89,7 +89,49 @@ void test_exec_child(void **state)
         ret = exec_child(child_tctx,
                          child_tctx->pipefd_to_child,
                          child_tctx->pipefd_from_child,
-                         CHILD_DIR"/"TEST_BIN, 2);
+                         CHILD_DIR"/"TEST_BIN, 2, NULL);
+        assert_int_equal(ret, EOK);
+    } else {
+            do {
+                errno = 0;
+                ret = waitpid(child_pid, &status, 0);
+            } while (ret == -1 && errno == EINTR);
+
+            if (ret > 0) {
+                ret = EIO;
+                if (WIFEXITED(status)) {
+                    ret = WEXITSTATUS(status);
+                    assert_int_equal(ret, 0);
+                }
+            } else {
+                DEBUG(SSSDBG_FUNC_DATA,
+                    "Failed to wait for children %d\n", child_pid);
+                ret = EIO;
+            }
+    }
+}
+
+/* Just make sure the exec works. The child does nothing but exits */
+void test_exec_child_extra_args(void **state)
+{
+    errno_t ret;
+    pid_t child_pid;
+    int status;
+    struct child_test_ctx *child_tctx = talloc_get_type(*state,
+                                                        struct child_test_ctx);
+    const char *extra_args[] = { "--guitar=george",
+                                 "--drums=ringo",
+                                 NULL };
+
+    setenv("TEST_CHILD_ACTION", "check_extra_args", 1);
+
+    child_pid = fork();
+    assert_int_not_equal(child_pid, -1);
+    if (child_pid == 0) {
+        ret = exec_child(child_tctx,
+                         child_tctx->pipefd_to_child,
+                         child_tctx->pipefd_from_child,
+                         CHILD_DIR"/"TEST_BIN, 2, extra_args);
         assert_int_equal(ret, EOK);
     } else {
             do {
@@ -126,6 +168,9 @@ int main(int argc, const char *argv[])
         unit_test_setup_teardown(test_exec_child,
                                  child_test_setup,
                                  child_test_teardown),
+        unit_test_setup_teardown(test_exec_child_extra_args,
+                                 child_test_setup,
+                                 child_test_teardown),
     };
 
     /* Set debug level to invalid value so we can deside if -d 0 was used. */
diff --git a/src/util/child_common.c b/src/util/child_common.c
index cc6a8fa75..9710630f9 100644
--- a/src/util/child_common.c
+++ b/src/util/child_common.c
@@ -623,6 +623,7 @@ static void child_invoke_callback(struct tevent_context *ev,
 static errno_t prepare_child_argv(TALLOC_CTX *mem_ctx,
                                   int child_debug_fd,
                                   const char *binary,
+                                  const char *extra_argv[],
                                   char ***_argv)
 {
     /*
@@ -632,6 +633,7 @@ static errno_t prepare_child_argv(TALLOC_CTX *mem_ctx,
     uint_t argc = 5;
     char ** argv;
     errno_t ret = EINVAL;
+    size_t i;
 
     /* Save the current state in case an interrupt changes it */
     bool child_debug_to_file = debug_to_file;
@@ -642,6 +644,10 @@ static errno_t prepare_child_argv(TALLOC_CTX *mem_ctx,
     if (child_debug_to_file) argc++;
     if (child_debug_stderr) argc++;
 
+    if (extra_argv) {
+        for (i = 0; extra_argv[i]; i++) argc++;
+    }
+
     /*
      * program name, debug_level, debug_to_file, debug_timestamps,
      * debug_microseconds and NULL
@@ -654,6 +660,17 @@ static errno_t prepare_child_argv(TALLOC_CTX *mem_ctx,
 
     argv[--argc] = NULL;
 
+    /* Add extra_attrs first */
+    if (extra_argv) {
+        for (i = 0; extra_argv[i]; i++) {
+            argv[--argc] = talloc_strdup(argv, extra_argv[i]);
+            if (argv[argc] == NULL) {
+                ret = ENOMEM;
+                goto fail;
+            }
+        }
+    }
+
     argv[--argc] = talloc_asprintf(argv, "--debug-level=%#.4x",
                               debug_level);
     if (argv[argc] == NULL) {
@@ -714,7 +731,8 @@ fail:
 
 errno_t exec_child(TALLOC_CTX *mem_ctx,
                    int *pipefd_to_child, int *pipefd_from_child,
-                   const char *binary, int debug_fd)
+                   const char *binary, int debug_fd,
+                   const char *extra_argv[])
 {
     int ret;
     errno_t err;
@@ -739,7 +757,8 @@ errno_t exec_child(TALLOC_CTX *mem_ctx,
     }
 
     ret = prepare_child_argv(mem_ctx, debug_fd,
-                             binary, &argv);
+                             binary, extra_argv,
+                             &argv);
     if (ret != EOK) {
         DEBUG(SSSDBG_CRIT_FAILURE, "prepare_child_argv.\n");
         return ret;
diff --git a/src/util/child_common.h b/src/util/child_common.h
index e159719a2..e659388ec 100644
--- a/src/util/child_common.h
+++ b/src/util/child_common.h
@@ -114,7 +114,8 @@ void child_sig_handler(struct tevent_context *ev,
 /* Never returns EOK, ether returns an error, or doesn't return on success */
 errno_t exec_child(TALLOC_CTX *mem_ctx,
                    int *pipefd_to_child, int *pipefd_from_child,
-                   const char *binary, int debug_fd);
+                   const char *binary, int debug_fd,
+                   const char *extra_argv[]);
 
 void child_cleanup(int readfd, int writefd);