[igt-dev] [PATCH i-g-t 2/9] lib/tests: Add support for redirecting fork output to /dev/null

Arkadiusz Hiler
2020-02-12T13:21:50Z

Trying to read interleaved writes is a bit tricky, so let's just use
/dev/null if we care about contents on only one of those pipes.

Signed-off-by: Arkadiusz Hiler <arkadiusz.hiler@intel.com>
---
lib/tests/igt_tests_common.h | 35 +++++++++++++++++++++++++++--------
1 file changed, 27 insertions(+), 8 deletions(-)

diff --git a/lib/tests/igt_tests_common.h b/lib/tests/igt_tests_common.h
index b3da3b34..f285d657 100644
--- a/lib/tests/igt_tests_common.h
+++ b/lib/tests/igt_tests_common.h
@@ -28,6 +28,8 @@
#include <assert.h>
#include <sys/wait.h>
#include <errno.h>
+#include <sys/stat.h>
+#include <fcntl.h>

/*
* We need to hide assert from the cocci igt test refactor spatch.
@@ -72,19 +74,32 @@ static inline pid_t do_fork_bg_with_pipes(void (*test_to_run)(void), int *out, i
int outfd[2], errfd[2];
pid_t pid;

- internal_assert(pipe(outfd) != -1);
- internal_assert(pipe(errfd) != -1);
+ if (out != NULL)
+ internal_assert(pipe(outfd) != -1);
+
+ if (err != NULL)
+ internal_assert(pipe(errfd) != -1);

pid = fork();
internal_assert(pid != -1);

if (pid == 0) {
+ /* we'll leak the /dev/null fds, let them die with the forked
+ * process, also close reading ends if they are any */
+ if (out == NULL)
+ outfd[1] = open("/dev/null", O_WRONLY);
+ else
+ close(outfd[0]);
+
+ if (err == NULL)
+ errfd[1] = open("/dev/null", O_WRONLY);
+ else
+ close(errfd[0]);
+
while (dup2(outfd[1], STDOUT_FILENO) == -1 && errno == EINTR) {}
while (dup2(errfd[1], STDERR_FILENO) == -1 && errno == EINTR) {}

- close(outfd[0]);
close(outfd[1]);
- close(errfd[0]);
close(errfd[1]);

test_to_run();
@@ -92,11 +107,15 @@ static inline pid_t do_fork_bg_with_pipes(void (*test_to_run)(void), int *out, i
exit(-1);
} else {
/* close the writing ends */
- close(outfd[1]);
- close(errfd[1]);
+ if (out != NULL) {
+ close(outfd[1]);
+ *out = outfd[0];
+ }

- *out = outfd[0];
- *err = errfd[0];
+ if (err != NULL) {
+ close(errfd[1]);
+ *err = errfd[0];
+ }

return pid;
}
--
2.24.1