Clean-up error message and test

Refactoring error messages:
 - standardize error messages and functions
 - return on error instead of exit
 - test error when target doesn't exist
 - include ability to capture stderr and stdout in the tests

5 files changed, 122 insertions, 58 deletions

diff --git a/common/util.h b/common/util.h
index 102b55b..ad2192b 100644
--- a/common/util.h
+++ b/common/util.h
@@ -8,6 +8,7 @@
 
 #include <string.h>
 #include <stdint.h>
+#include <errno.h>
 
 #define BIT(n)			(1UL << (n))
 
@@ -33,6 +34,17 @@ void debug(const char *format, ...);
 		exit(EXIT_FAILURE);					\
 	} while (0)
 
+#define ret_err(e, ...)                                             \
+	do {                                                        \
+		if (errno == 0) {                                   \
+			err(__VA_ARGS__);                           \
+		} else {                                            \
+			fprintf(stderr, __VA_ARGS__);               \
+			fprintf(stderr, ": %s\n", strerror(errno)); \
+		}                                                   \
+		return (e);                                         \
+	} while (0)
+
 /**
  * From the Linux kernel, include/linux/log2.h:
  *
diff --git a/operations.c b/operations.c
index d6a9245..47a9a9f 100644
--- a/operations.c
+++ b/operations.c
@@ -11,7 +11,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <errno.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <sched.h>
@@ -24,6 +23,7 @@
 #include <errno.h>
 
 #include "common/gluten.h"
+#include "common/util.h"
 #include "operations.h"
 
 static bool is_cookie_valid(int notifyFd, uint64_t id)
@@ -33,34 +33,22 @@ static bool is_cookie_valid(int notifyFd, uint64_t id)
 
 static int send_target(const struct seccomp_notif_resp *resp, int notifier)
 {
-	if (!is_cookie_valid(notifier, resp->id)) {
-		fprintf(stderr,
-			"the response id isn't valid\ncheck if the targets has already terminated\n");
-		exit(0);
-	}
-	if (ioctl(notifier, SECCOMP_IOCTL_NOTIF_SEND, resp) < 0) {
-		if (errno != EINPROGRESS) {
-			perror("sending the response");
-			return -1;
-		}
-	}
+	if (!is_cookie_valid(notifier, resp->id))
+		ret_err(-1, "the response id isn't valid");
+	if (ioctl(notifier, SECCOMP_IOCTL_NOTIF_SEND, resp) < 0)
+		if (errno != EINPROGRESS)
+			ret_err(-1, "sending the response");
 	return 0;
 }
 
 static int send_inject_target(const struct seccomp_notif_addfd *resp,
 			      int notifier)
 {
-	if (!is_cookie_valid(notifier, resp->id)) {
-		fprintf(stderr,
-			"the response id isn't valid\ncheck if the targets has already terminated\n");
-		return -1;
-	}
-	if (ioctl(notifier, SECCOMP_IOCTL_NOTIF_ADDFD, resp) < 0) {
-		if (errno != EINPROGRESS) {
-			perror("sending the response");
-			return -1;
-		}
-	}
+	if (!is_cookie_valid(notifier, resp->id))
+		ret_err(-1, "the response id isn't valid");
+	if (ioctl(notifier, SECCOMP_IOCTL_NOTIF_ADDFD, resp) < 0)
+		if (errno != EINPROGRESS)
+			ret_err(-1, "sending the response");
 	return 0;
 }
 
@@ -92,7 +80,7 @@ static void proc_ns_name(unsigned i, char *ns)
 		snprintf(ns, PATH_MAX + 1, "time");
 		break;
 	default:
-		fprintf(stderr, "unrecognized namespace index %d\n", i);
+		err("unrecognized namespace index %d\n", i);
 	}
 }
 
@@ -123,16 +111,11 @@ static int set_namespaces(const struct op_call *a, int tpid)
 			break;
 		}
 
-		if ((fd = open(path, O_CLOEXEC)) < 0) {
-			fprintf(stderr, "open for file %s: %s", path,
-				strerror(errno));
-			return -1;
-		}
+		if ((fd = open(path, O_CLOEXEC)) < 0)
+			ret_err(-1, "open for file %s", path);
 
-		if (setns(fd, 0) != 0) {
-			perror("setns");
-			return -1;
-		}
+		if (setns(fd, 0) != 0)
+			ret_err(-1, "setns");
 	}
 	return 0;
 }
@@ -164,16 +147,14 @@ int op_load(const struct seccomp_notif *req, int notifier, struct gluten *g,
 	int fd, ret = 0;
 
 	snprintf(path, sizeof(path), "/proc/%d/mem", req->pid);
-	if ((fd = open(path, O_RDONLY | O_CLOEXEC)) < 0) {
-		perror("open mem");
-		return -1;
-	}
+	if ((fd = open(path, O_RDONLY | O_CLOEXEC)) < 0)
+		ret_err(-1, "error opening mem for %d", req->pid);
 
 	/*
          * Avoid the TOCTOU and check if the read mappings are still valid
          */
 	if (!is_cookie_valid(notifier, req->id)) {
-		fprintf(stderr, "the seccomp request isn't valid anymore\n");
+		err("the seccomp request isn't valid anymore");
 		ret = -1;
 		goto out;
 	}
@@ -182,8 +163,9 @@ int op_load(const struct seccomp_notif *req, int notifier, struct gluten *g,
 		goto out;
 	}
 	if (pread(fd, gluten_write_ptr(g, load->dst), load->size, *src) < 0) {
-		perror("pread");
-		return -1;
+		err("pread");
+		ret = -1;
+		goto out;
 	}
 
 out:
@@ -199,10 +181,8 @@ int do_call(struct arg_clone *c)
 	/* Create a process that will be moved to the namespace */
 	child = clone(execute_syscall, stack + sizeof(stack),
 		      CLONE_FILES | CLONE_VM | SIGCHLD, (void *)c);
-	if (child == -1) {
-		perror("clone");
-		return -1;
-	}
+	if (child == -1)
+		ret_err(-1, "clone");
 	wait(NULL);
 	return 0;
 }
@@ -267,7 +247,8 @@ int op_return(const struct seccomp_notif *req, int notifier, struct gluten *g,
 	resp.flags = 0;
 	resp.error = 0;
 
-	if (gluten_read(&req->data, g, &resp.val, op->val, sizeof(resp.val)) == -1)
+	if (gluten_read(&req->data, g, &resp.val, op->val, sizeof(resp.val)) ==
+	    -1)
 		return -1;
 
 	if (send_target(&resp, notifier) == -1)
@@ -304,9 +285,11 @@ static int do_inject(const struct seccomp_notif *req, int notifier,
 	resp.newfd_flags = 0;
 	resp.id = req->id;
 
-	if(gluten_read(&req->data, g, &resp.newfd, op->new_fd, sizeof(resp.newfd)) == -1)
+	if (gluten_read(&req->data, g, &resp.newfd, op->new_fd,
+			sizeof(resp.newfd)) == -1)
 		return -1;
-	if(gluten_read(&req->data, g, &resp.srcfd, op->old_fd, sizeof(resp.srcfd)) == -1)
+	if (gluten_read(&req->data, g, &resp.srcfd, op->old_fd,
+			sizeof(resp.srcfd)) == -1)
 		return -1;
 
 	if (atomic)
@@ -363,18 +346,14 @@ int op_resolve_fd(const struct seccomp_notif *req, int notifier,
 
 	(void)notifier;
 
-
-	if(gluten_read(NULL, g, &path, op->path, sizeof(op->path_size)) == -1)
+	if (gluten_read(NULL, g, &path, op->path, sizeof(op->path_size)) == -1)
 		return -1;
-	if(gluten_read(&req->data, g, &fd, op->fd, sizeof(fd)) == -1)
+	if (gluten_read(&req->data, g, &fd, op->fd, sizeof(fd)) == -1)
 		return -1;
 
 	snprintf(fdpath, PATH_MAX, "/proc/%d/fd/%d", req->pid, fd);
-	if ((nbytes = readlink(fdpath, buf, op->path_size)) < 0) {
-		fprintf(stderr, "error reading %s\n", fdpath);
-		perror("readlink");
-		return -1;
-	}
+	if ((nbytes = readlink(fdpath, buf, op->path_size)) < 0)
+		ret_err(-1, "error reading %s", fdpath);
 	if (strcmp(path, buf) == 0)
 		return op->jmp;
 
@@ -382,7 +361,7 @@ int op_resolve_fd(const struct seccomp_notif *req, int notifier,
 }
 
 int eval(struct gluten *g, struct op *ops, const struct seccomp_notif *req,
-	  int notifier)
+	 int notifier)
 {
 	struct op *op = ops;
 
@@ -398,7 +377,7 @@ int eval(struct gluten *g, struct op *ops, const struct seccomp_notif *req,
 			HANDLE_OP(OP_CMP, op_cmp, cmp);
 			HANDLE_OP(OP_RESOLVEDFD, op_resolve_fd, resfd);
 		default:
-			fprintf(stderr, "unknown operation %d \n", op->type);
+			ret_err(-1, "unknown operation %d", op->type);
 		}
 	}
 	return 0;
diff --git a/tests/unit/test_errors.c b/tests/unit/test_errors.c
index 06bae12..51fc3db 100644
--- a/tests/unit/test_errors.c
+++ b/tests/unit/test_errors.c
@@ -19,6 +19,11 @@ static void setup_error_check()
 	setup();
 }
 
+static void setup_stderr()
+{
+	ck_stderr();
+}
+
 struct gluten_offset test_max_size_data[] = {
 	{ OFFSET_DATA, DATA_SIZE },
 	{ OFFSET_RO_DATA, RO_DATA_SIZE },
@@ -105,11 +110,50 @@ START_TEST(test_op_cmp)
 
 	ck_assert_int_eq(eval(&gluten, ops, &req, notifyfd), -1);
 }
+static struct ttargetnoexisting_data {
+	struct op op;
+	char err_msg[BUFSIZ];
+};
+
+struct ttargetnoexisting_data test_target_noexisting_data[] = {
+	{ { OP_CONT, { { 0 } } }, "the response id isn't valid" },
+	{ { OP_BLOCK, { { 0 } } }, "the response id isn't valid" },
+	{ { OP_RETURN, { { 0 } } }, "the response id isn't valid" },
+	{ { OP_INJECT,
+	    { .inject = { { OFFSET_DATA, 0 }, { OFFSET_DATA, 0 } } } },
+	  "the response id isn't valid" },
+	{ { OP_INJECT_A,
+	    { .inject = { { OFFSET_DATA, 0 }, { OFFSET_DATA, 0 } } } },
+	  "the response id isn't valid" },
+	{ { OP_CALL, { .call = { __NR_getpid, false } } },
+	  "the response id isn't valid" },
+	{ { OP_LOAD,
+	    { .load = { { OFFSET_SECCOMP_DATA, 1 }, { OFFSET_DATA, 0 }, 0 } } },
+	  "error opening mem for" },
+	{ { OP_RESOLVEDFD,
+	    { .resfd = { { OFFSET_SECCOMP_DATA, 1 },
+			 { OFFSET_DATA, 0 },
+			 0,
+			 0 } } },
+	  "error reading /proc" },
+};
+
+START_TEST(test_target_noexisting)
+{
+	struct op ops[2];
+
+	ops[0] = test_target_noexisting_data[_i].op;
+	ops[1].type = OP_END;
+
+	ck_assert_int_eq(eval(&gluten, ops, &req, notifyfd), -1);
+	ck_error_msg(test_target_noexisting_data[_i].err_msg);
+}
 
 Suite *error_suite(void)
 {
 	Suite *s;
 	TCase *bounds, *gwrite, *gread, *gcmp;
+	TCase *tnotexist;
 
 	s = suite_create("Error handling");
 
@@ -138,6 +182,12 @@ Suite *error_suite(void)
 			    sizeof(test_cmp_data) / sizeof(test_cmp_data[0]));
 	suite_add_tcase(s, gcmp);
 
+	tnotexist = tcase_create("target not existing");
+	tcase_add_checked_fixture(tnotexist, setup_stderr, NULL);
+	tcase_add_loop_test(tnotexist, test_target_noexisting, 0,
+			    ARRAY_SIZE(test_target_noexisting_data));
+	suite_add_tcase(s, tnotexist);
+
 	return s;
 }
 
diff --git a/tests/unit/testutil.h b/tests/unit/testutil.h
index ec881c7..861efb0 100644
--- a/tests/unit/testutil.h
+++ b/tests/unit/testutil.h
@@ -1,6 +1,6 @@
 #ifndef TESTUTIL_H
 #define TESTUTIL_H
-
+#include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <stdbool.h>
@@ -67,6 +67,8 @@ extern struct args_target *at;
 extern int pipefd[2];
 extern pid_t pid;
 extern char path[PATH_MAX];
+extern char stderr_buff[BUFSIZ];
+extern char stdout_buff[BUFSIZ];
 
 extern struct gluten gluten;
 
@@ -85,4 +87,7 @@ void continue_target();
 void mock_syscall_target();
 void set_args_no_check(struct args_target *at);
 void check_target_result_nonegative();
+void ck_error_msg(char *s);
+void ck_stderr();
+void ck_stdout();
 #endif /* TESTUTIL_H */
diff --git a/tests/unit/util.c b/tests/unit/util.c
index 45171f2..5c36c54 100644
--- a/tests/unit/util.c
+++ b/tests/unit/util.c
@@ -30,6 +30,8 @@ int pipefd[2];
 pid_t pid;
 char path[PATH_MAX] = "/tmp/test-seitan";
 struct gluten gluten;
+char stderr_buff[BUFSIZ];
+char stdout_buff[BUFSIZ];
 
 int install_notification_filter(struct args_target *at)
 {
@@ -231,3 +233,19 @@ void teardown()
 		munmap(at, sizeof(struct args_target));
 	unlink(path);
 }
+
+void ck_stderr()
+{
+	setbuf(stderr, stderr_buff);
+}
+
+void ck_stdout()
+{
+	setbuf(stdout, stdout_buff);
+}
+
+void ck_error_msg(char *s)
+{
+	ck_assert_msg(strstr(stderr_buff, s) != NULL, "err=\"%s\" doesn't contain \"%s\" ",
+		      stderr_buff, s);
+}