[RFC v1] [GSoC] Add test for -l/--syscall-limit option

[Sahil Siddiq]

This test checks the correctness of the -l/--syscall-limit
option when used with the --trace option

* test/strace--syscall-limit.c: New file
* test/gen_tests.in: Add rule to generate test
* test/Makefile.am (check_PROGRAMS): Add strace--syscall-limit
* test/.gitignore: Add strace--syscall-limit

Signed-off-by: Sahil Siddiq <icegambit91 at gmail.com>
---
Hi,

I haven't finished writing all the tests yet. I have to admit
that I found the learning curve for writing tests to be a lot
higher than working on the actual feature especially since I
am not used to working with bash scripts. So, this has been a
nice learning experience.

I would like to get some feedback on this test before I move
on to the other tests. It checks the correctness of the -l
option with the --trace option.

I went through several of the existing tests to understand how
best to write this test. I primarily took inspiration from the
"syscall--decode-pids-comm" test. Please do let me know if the
test can be improved.

Thanks,
Sahil

 tests/.gitignore              |  1 +
 tests/Makefile.am             |  1 +
 tests/gen_tests.in            |  1 +
 tests/strace--syscall-limit.c | 60 +++++++++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+)
 create mode 100644 tests/strace--syscall-limit.c

diff --git a/tests/.gitignore b/tests/.gitignore
index 5935c39d9..65999ad24 100644
--- a/tests/.gitignore
+++ b/tests/.gitignore
@@ -1020,6 +1020,7 @@ strace--strings-in-hex-all
 strace--strings-in-hex-non-ascii
 strace--strings-in-hex-non-ascii-chars
 strace--strings-in-hex-none
+strace--syscall-limit
 strace-Y-0123456789
 strace-n
 strace-no-x
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 4426cab0c..cc4fae736 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -379,6 +379,7 @@ check_PROGRAMS = $(PURE_EXECUTABLES) \
 	status-successful-threads \
 	status-unfinished-threads \
 	strace--decode-pids-comm \
+	strace--syscall-limit \
 	strace-Y-0123456789 \
 	strace-p-Y-p2 \
 	strace-p1-Y-p \
diff --git a/tests/gen_tests.in b/tests/gen_tests.in
index eceac8d60..c11c49329 100644
--- a/tests/gen_tests.in
+++ b/tests/gen_tests.in
@@ -995,6 +995,7 @@ strace--absolute-timestamps-format-unix-precision-ns +strace-ttt.test 9 --absolu
 strace--absolute-timestamps-format-unix-precision-s +strace-ttt.test 0 --absolute-timestamps=format:unix --absolute-timestamps=precision:s
 strace--absolute-timestamps-format-unix-precision-us +strace-ttt.test 6 --absolute-timestamps=precision:us --absolute-timestamps=format:unix
 strace--decode-pids-comm	--decode-pids=comm --trace=getppid,tgkill --signal='!SIGCHLD,SIGCONT' -q -f -a 18
+strace--syscall-limit	--syscall-limit=4 --trace=getpid,getppid -q -f -a 9
 strace--follow-forks-output-separately +strace-ff.test --follow-forks --output-separately
 strace--relative-timestamps +strace-r.test --relative-timestamps
 strace--relative-timestamps-ms +strace-r.test --relative-timestamps=ms
diff --git a/tests/strace--syscall-limit.c b/tests/strace--syscall-limit.c
new file mode 100644
index 000000000..0905ebd85
--- /dev/null
+++ b/tests/strace--syscall-limit.c
@@ -0,0 +1,60 @@
+/*
+ * Test -l/--syscall-limit=limit option.
+ *
+ * Copyright (c) 2023 The strace developers.
+ * All rights reserved.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "tests.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+static int
+syscall_limit_detach(void)
+{
+	pid_t pid  = getpid();
+	pid_t ppid = getppid();
+
+	printf("%u getpid() = %d\n", pid, pid);
+	printf("%u getppid() = %d\n", pid, ppid);
+	fflush(stdout);
+
+	pid_t child = fork();
+	if (child < 0)
+		perror_msg_and_fail("fork");
+	else if (child == 0) {
+		pid = getpid();
+		ppid = getppid();
+		printf("%u getpid() = %d\n", pid, pid);
+		printf("%u getppid() = %d\n", pid, ppid);
+		fflush(stdout);
+		return 0;
+	}
+	int status;
+	while ((waitpid(child, &status, 0)) != child) {
+		if (errno == EINTR)
+			continue;
+		perror_msg_and_fail("waitpid: %d", child);
+	}
+	printf("+++ exited with 0 +++\n");
+
+	ppid = getpid();
+	ppid = getppid();
+	printf("%u getpid() = %d\n", pid, pid);
+	printf("%u getppid() = %d\n", pid, ppid);
+	printf("+++ exited with 0 +++\n");
+	return WEXITSTATUS(status);
+}
+
+int
+main(int argc, char **argv)
+{
+	return syscall_limit_detach();
+}
-- 
2.39.2