tracing: Support poll on event hist file

From: Masami Hiramatsu (Google) <[email protected]>

Add a testcase for poll() on hist file. This introduces a helper binary to the ftracetest, because there is no good way to reliably execute poll() on hist file.

Signed-off-by Masami Hiramatsu (Google) <[email protected]>

---
Changes in v4:
- Use getopt() in poll.c (command options are changed)
- Update test code according to the new command options.
Changes in v2:
- Update poll command to support both of POLLIN and POLLPRI, and timeout.
- Identify unsupported stable kernel if poll-in returns soon.
- Test both of POLLIN and POLLPRI.

---
  tools/testing/selftests/ftrace/Makefile            |    2 +
  tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
  .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
  3 files changed, 150 insertions(+)

create mode 100644 tools/testing/selftests/ftrace/poll.c
create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc

tools/testing/selftests/ftrace/Makefile +2 -0

index a1e955d2de4c..49d96bb16355 100644
@@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
  TEST_FILES := test.d settings
  EXTRA_CLEAN := $(OUTPUT)/logs/*
 
+TEST_GEN_PROGS = poll
+
  include ../lib.mk

tools/testing/selftests/ftrace/poll.c new file +59 -0

new file mode 100644
index 000000000000..584f159654b1
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple poll on a file.
+ *
+ * Copyright (c) 2024 Google LLC.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define BUFSIZE 4096
+
+/*
+ * Usage:
+ *  poll [-I|-P] [-t timeout] FILE
+ */
+int main(int argc, char *argv[])
+{
+	struct pollfd pfd = {.events = POLLIN};
+	char buf[BUFSIZE];
+	int timeout = -1;
+	int ret, opt;
+
+	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
+		switch (opt) {
+		case 'I':
+			pfd.events = POLLIN;
+			break;
+		case 'P':
+			pfd.events = POLLPRI;
+			break;
+		case 't':
+			timeout = atoi(optarg);
+			break;
+		default:
+			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
+				argv[0]);
+			return -1;
+		}
+	}
+	if (optind >= argc) {
+		fprintf(stderr, "Error: Polling file is not specified\n");
+		return -1;
+	}
+
+	pfd.fd = open(argv[optind], O_RDONLY);
+	if (pfd.fd < 0) {
+		fprintf(stderr, "failed to open %s", argv[optind]);
+		perror("open");
+		return -1;
+	}
+
+	/* Reset poll by read if POLLIN is specified. */
+	if (pfd.events & POLLIN)

Quoted 103 lines · Masami Hiramatsu (Google)

From: Masami Hiramatsu (Google) <[email protected]>

Add a testcase for poll() on hist file. This introduces a helper binary to the ftracetest, because there is no good way to reliably execute poll() on hist file.

Signed-off-by Masami Hiramatsu (Google) <[email protected]>

---
Changes in v4:
- Use getopt() in poll.c (command options are changed)
- Update test code according to the new command options.
Changes in v2:
- Update poll command to support both of POLLIN and POLLPRI, and timeout.
- Identify unsupported stable kernel if poll-in returns soon.
- Test both of POLLIN and POLLPRI.

---
  tools/testing/selftests/ftrace/Makefile            |    2 +
  tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
  .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
  3 files changed, 150 insertions(+)

create mode 100644 tools/testing/selftests/ftrace/poll.c
create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc

tools/testing/selftests/ftrace/Makefile +2 -0

index a1e955d2de4c..49d96bb16355 100644
@@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
  TEST_FILES := test.d settings
  EXTRA_CLEAN := $(OUTPUT)/logs/*
 
+TEST_GEN_PROGS = poll
+
  include ../lib.mk

tools/testing/selftests/ftrace/poll.c new file +63 -0

new file mode 100644
index 000000000000..584f159654b1
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple poll on a file.
+ *
+ * Copyright (c) 2024 Google LLC.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define BUFSIZE 4096
+
+/*
+ * Usage:
+ *  poll [-I|-P] [-t timeout] FILE
+ */
+int main(int argc, char *argv[])
+{
+	struct pollfd pfd = {.events = POLLIN};
+	char buf[BUFSIZE];
+	int timeout = -1;
+	int ret, opt;
+
+	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
+		switch (opt) {
+		case 'I':
+			pfd.events = POLLIN;
+			break;
+		case 'P':
+			pfd.events = POLLPRI;
+			break;
+		case 't':
+			timeout = atoi(optarg);
+			break;
+		default:
+			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
+				argv[0]);
+			return -1;
+		}
+	}
+	if (optind >= argc) {
+		fprintf(stderr, "Error: Polling file is not specified\n");
+		return -1;
+	}
+
+	pfd.fd = open(argv[optind], O_RDONLY);
+	if (pfd.fd < 0) {
+		fprintf(stderr, "failed to open %s", argv[optind]);
+		perror("open");
+		return -1;
+	}
+
+	/* Reset poll by read if POLLIN is specified. */
+	if (pfd.events & POLLIN)
+		do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
+
+	ret = poll(&pfd, 1, timeout);
+	if (ret < 0 && errno != EINTR) {

tools/testing/selftests/ftrace/poll.c line 69

Quoted 6 lines

tools/testing/selftests/ftrace/poll.c new file +6 -0

+		perror("poll");
+		return -1;
+	}
+	close(pfd.fd);
+
+	/* If timeout happned, return code is 0 */

Looks like you missed this one :) Otherwise looks good to me.

With this fixed

Reviewed-by Shuah Khan <[email protected]>

thanks,
-- Shuah

Quoted 104 lines · On Fri, 16 Aug 2024 08:04:41 -0600 Shuah Khan <[email protected]> wrote:

Quoted 103 lines · Masami Hiramatsu (Google)

From: Masami Hiramatsu (Google) <[email protected]>

Add a testcase for poll() on hist file. This introduces a helper binary to the ftracetest, because there is no good way to reliably execute poll() on hist file.

Signed-off-by Masami Hiramatsu (Google) <[email protected]>

---
Changes in v4:
- Use getopt() in poll.c (command options are changed)
- Update test code according to the new command options.
Changes in v2:
- Update poll command to support both of POLLIN and POLLPRI, and timeout.
- Identify unsupported stable kernel if poll-in returns soon.
- Test both of POLLIN and POLLPRI.

---
  tools/testing/selftests/ftrace/Makefile            |    2 +
  tools/testing/selftests/ftrace/poll.c              |   74 ++++++++++++++++++++
  .../ftrace/test.d/trigger/trigger-hist-poll.tc     |   74 ++++++++++++++++++++
  3 files changed, 150 insertions(+)

create mode 100644 tools/testing/selftests/ftrace/poll.c
create mode 100644 tools/testing/selftests/ftrace/test.d/trigger/trigger-hist-poll.tc

tools/testing/selftests/ftrace/Makefile +2 -0

index a1e955d2de4c..49d96bb16355 100644
@@ -6,4 +6,6 @@ TEST_PROGS := ftracetest-ktap
  TEST_FILES := test.d settings
  EXTRA_CLEAN := $(OUTPUT)/logs/*
 
+TEST_GEN_PROGS = poll
+
  include ../lib.mk

tools/testing/selftests/ftrace/poll.c new file +63 -0

new file mode 100644
index 000000000000..584f159654b1
@@ -0,0 +1,74 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Simple poll on a file.
+ *
+ * Copyright (c) 2024 Google LLC.
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define BUFSIZE 4096
+
+/*
+ * Usage:
+ *  poll [-I|-P] [-t timeout] FILE
+ */
+int main(int argc, char *argv[])
+{
+	struct pollfd pfd = {.events = POLLIN};
+	char buf[BUFSIZE];
+	int timeout = -1;
+	int ret, opt;
+
+	while ((opt = getopt(argc, argv, "IPt:")) != -1) {
+		switch (opt) {
+		case 'I':
+			pfd.events = POLLIN;
+			break;
+		case 'P':
+			pfd.events = POLLPRI;
+			break;
+		case 't':
+			timeout = atoi(optarg);
+			break;
+		default:
+			fprintf(stderr, "Usage: %s [-I|-P] [-t timeout] FILE\n",
+				argv[0]);
+			return -1;
+		}
+	}
+	if (optind >= argc) {
+		fprintf(stderr, "Error: Polling file is not specified\n");
+		return -1;
+	}
+
+	pfd.fd = open(argv[optind], O_RDONLY);
+	if (pfd.fd < 0) {
+		fprintf(stderr, "failed to open %s", argv[optind]);
+		perror("open");
+		return -1;
+	}
+
+	/* Reset poll by read if POLLIN is specified. */
+	if (pfd.events & POLLIN)
+		do {} while (read(pfd.fd, buf, BUFSIZE) == BUFSIZE);
+
+	ret = poll(&pfd, 1, timeout);
+	if (ret < 0 && errno != EINTR) {

Quoted 9 lines

tools/testing/selftests/ftrace/poll.c line 69

Quoted 6 lines

tools/testing/selftests/ftrace/poll.c new file +6 -0

+		perror("poll");
+		return -1;
+	}
+	close(pfd.fd);
+
+	/* If timeout happned, return code is 0 */

Looks like you missed this one :) Otherwise looks good to me.

Oops, indeed.

Quoted 4 lines

With this fixed

Reviewed-by Shuah Khan <[email protected]>

Thanks!

Quoted 3 lines

thanks,
-- Shuah

Signature · 1 line

Masami Hiramatsu (Google) <[email protected]>