[PATCH] selftests/proc/proc-empty-vm.c: Test for unmapped process

[PATCH] selftests/proc/proc-empty-vm.c: Test for unmapped process

[Siddharth Menon]

Check if VMsize is 0 to determine whether the process has been unmapped.
The child process cannot signal the parent that it has unmapped itself,
as it no longer exists. This includes unmapping the text segment,
preventing the child from proceeding to the next instruction.

Signed-off-by: Siddharth Menon <simeddon@gmail.com>
---
 tools/testing/selftests/proc/proc-empty-vm.c | 50 ++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/tools/testing/selftests/proc/proc-empty-vm.c b/tools/testing/selftests/proc/proc-empty-vm.c
index b3f898aab4ab..8ee000b0ddd7 100644
--- a/tools/testing/selftests/proc/proc-empty-vm.c
+++ b/tools/testing/selftests/proc/proc-empty-vm.c
@@ -213,6 +213,53 @@ static void vsyscall(void)
 }
 #endif
 
+static int test_proc_pid_mem(pid_t pid)
+{
+	char buf[4096];
+	char *line;
+	int vm_size = -1;
+
+	snprintf(buf, sizeof(buf), "/proc/%d/status", pid);
+	int fd = open(buf, O_RDONLY);
+
+	if (fd == -1) {
+		if (errno == ENOENT) {
+			// Process does not exist
+			return EXIT_SUCCESS;
+		}
+	perror("open /proc/[pid]/status");
+	return EXIT_FAILURE;
+	}
+
+	ssize_t rv = read(fd, buf, sizeof(buf) - 1);
+
+	if (rv == -1) {
+		perror("read");
+		close(fd);
+		return EXIT_FAILURE;
+	}
+	buf[rv] = '\0';
+
+	line = strtok(buf, "\n");
+	while (line != NULL) {
+		// Check for VmSize
+		if (strncmp(line, "VmSize:", 7) == 0) {
+			sscanf(line, "VmSize: %d", &vm_size);
+			break;
+		}
+		line = strtok(NULL, "\n");
+	}
+
+	close(fd);
+
+	// Check if VmSize is 0
+	if (vm_size == 0) {
+		return EXIT_SUCCESS;
+	}
+
+	return EXIT_FAILURE;
+}
+
 static int test_proc_pid_maps(pid_t pid)
 {
 	char buf[4096];
@@ -508,6 +555,9 @@ int main(void)
 		 */
 		sleep(1);
 
+		if (rv == EXIT_SUCCESS) {
+			rv = test_proc_pid_mem(pid);
+		}
 		if (rv == EXIT_SUCCESS) {
 			rv = test_proc_pid_maps(pid);
 		}
-- 
2.39.5

Re: [PATCH] selftests/proc/proc-empty-vm.c: Test for unmapped process

[Shuah Khan]

On 9/30/24 10:09, Siddharth Menon wrote:
> Check if VMsize is 0 to determine whether the process has been unmapped.
> The child process cannot signal the parent that it has unmapped itself,
> as it no longer exists. This includes unmapping the text segment,
> preventing the child from proceeding to the next instruction.

Short log: Add test for unmapped process instead of "Test for"

Also you can include just: selftests/proc in shortlog and mention
the routine you care fixing.

Are you fixing a TODO? Mention that as well and cleanup the
TODO since it is fixed.

> 
> Signed-off-by: Siddharth Menon <simeddon@gmail.com>
> ---
>   tools/testing/selftests/proc/proc-empty-vm.c | 50 ++++++++++++++++++++
>   1 file changed, 50 insertions(+)
> 
> diff --git a/tools/testing/selftests/proc/proc-empty-vm.c b/tools/testing/selftests/proc/proc-empty-vm.c
> index b3f898aab4ab..8ee000b0ddd7 100644
> --- a/tools/testing/selftests/proc/proc-empty-vm.c
> +++ b/tools/testing/selftests/proc/proc-empty-vm.c
> @@ -213,6 +213,53 @@ static void vsyscall(void)
>   }
>   #endif
>   
> +static int test_proc_pid_mem(pid_t pid)
> +{
> +	char buf[4096];
> +	char *line;
> +	int vm_size = -1;
> +
> +	snprintf(buf, sizeof(buf), "/proc/%d/status", pid);
> +	int fd = open(buf, O_RDONLY);
> +
> +	if (fd == -1) {
> +		if (errno == ENOENT) {
> +			// Process does not exist

This isn't the right comment block - please refer to coding style doc
in the repo. Maintain the comment style in this file.

> +			return EXIT_SUCCESS;
> +		}
> +	perror("open /proc/[pid]/status");
> +	return EXIT_FAILURE;
> +	}
> +
> +	ssize_t rv = read(fd, buf, sizeof(buf) - 1);
> +
> +	if (rv == -1) {
> +		perror("read");

Change this
> +		close(fd);
> +		return EXIT_FAILURE;
> +	}
> +	buf[rv] = '\0';
> +
> +	line = strtok(buf, "\n");
> +	while (line != NULL) {
> +		// Check for VmSize

Same here

> +		if (strncmp(line, "VmSize:", 7) == 0) {
> +			sscanf(line, "VmSize: %d", &vm_size);
> +			break;
> +		}
> +		line = strtok(NULL, "\n");
> +	}
> +
> +	close(fd);
> +
> +	// Check if VmSize is 0

Same here

> +	if (vm_size == 0) {
> +		return EXIT_SUCCESS;
> +	}
> +

Did you run checkpatch - you don't need { } for a single line
conditional.

> +	return EXIT_FAILURE;
> +}
> +
>   static int test_proc_pid_maps(pid_t pid)
>   {
>   	char buf[4096];
> @@ -508,6 +555,9 @@ int main(void)
>   		 */
>   		sleep(1);
>   
> +		if (rv == EXIT_SUCCESS) {
> +			rv = test_proc_pid_mem(pid);
> +		}
>   		if (rv == EXIT_SUCCESS) {
>   			rv = test_proc_pid_maps(pid);
>   		}

Also add everybody get_maintianer.pl suggests when you send v2.
You are missing key reviewers and maintainers.

thanks,
-- Shuah