Re: [PATCH] selftest: add a test case to check how locks are shown in fdinfo

[Shuah Khan]

Hi Andrey,

Looks good in general. Couple of comments.

On 03/12/2015 10:30 AM, Andrey Vagin wrote:
> The main idea of this test is to check that locks are shown correctly
> when they can't be placed in a default seq_file buffer due to its size.
> 
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
> Signed-off-by: Andrey Vagin <avagin@xxxxxxxxxx>
> ---
>  tools/testing/selftests/Makefile        |   1 +
>  tools/testing/selftests/fdinfo/Makefile |  11 +++
>  tools/testing/selftests/fdinfo/locks.c  | 119 ++++++++++++++++++++++++++++++++
>  3 files changed, 131 insertions(+)
>  create mode 100644 tools/testing/selftests/fdinfo/Makefile
>  create mode 100644 tools/testing/selftests/fdinfo/locks.c
> 
> diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
> index 4e51122..8cd57f6 100644
> --- a/tools/testing/selftests/Makefile
> +++ b/tools/testing/selftests/Makefile
> @@ -17,6 +17,7 @@ TARGETS += sysctl
>  TARGETS += timers
>  TARGETS += user
>  TARGETS += vm
> +TARGETS += fdinfo
>  #Please keep the TARGETS list alphabetically sorted

Please move the new target up to keep the TARGETS list
alphabetically sorted. This helps avoid conflicts as new
tests get added.

>  
>  TARGETS_HOTPLUG = cpu-hotplug
> diff --git a/tools/testing/selftests/fdinfo/Makefile b/tools/testing/selftests/fdinfo/Makefile
> new file mode 100644
> index 0000000..83f34ef
> --- /dev/null
> +++ b/tools/testing/selftests/fdinfo/Makefile
> @@ -0,0 +1,11 @@
> +CFLAGS += -Wall
> +
> +all: locks
> +
> +run_tests: all
> +	@./locks || echo "locks: [FAIL]"
> +
> +locks: locks.c
> +
> +clean:
> +	rm -f locks
> diff --git a/tools/testing/selftests/fdinfo/locks.c b/tools/testing/selftests/fdinfo/locks.c
> new file mode 100644
> index 0000000..93f25c6
> --- /dev/null
> +++ b/tools/testing/selftests/fdinfo/locks.c
> @@ -0,0 +1,119 @@
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <unistd.h>
> +#include <string.h>
> +#include <sys/types.h>
> +#include <sys/stat.h>
> +#include <fcntl.h>
> +
> +#define pr_perror(fmt, ...) fprintf(stderr, "%s:%d: " fmt ": %m\n", \
> +					__FILE__, __LINE__, ##__VA_ARGS__)
> +
> +#define FILE_SIZE 4096
> +
> +int main(int argc, char **argv)
> +{
> +	int fd, fdinfo, i, ret, size, bsize = 4096;
> +	char *buf, *p, fdinfo_path[] = "/proc/self/fdinfo/XXXXXXXXXX";
> +
> +	fd = open("test_file", O_RDWR | O_CREAT, 0666);
> +	if (fd == -1) {
> +		pr_perror("Unable to open test_file");
> +		return 1;
> +	}
> +	unlink("test_file");
> +	if (ftruncate(fd, FILE_SIZE) == -1) {
> +		pr_perror("Unable to truncate test_file");
> +		return 1;
> +	}
> +
> +	/*
> +	 * Generate FILE_SIZE locks. We are going to exceed the default
> +	 * size of seq buffer
> +	 */
> +	for (i = 0; i < FILE_SIZE; i++) {
> +		struct flock lock;
> +
> +		if (i % 2)
> +			lock.l_type = F_WRLCK;
> +		else
> +			lock.l_type = F_RDLCK;
> +		lock.l_whence = SEEK_SET;
> +		lock.l_start  = i;
> +		lock.l_len    = 1;
> +		lock.l_pid    = -1;
> +		if (fcntl(fd, F_SETLK, &lock)) {
> +			pr_perror("Unable to set lock %d\n", i);
> +			return 1;
> +		}
> +	}
> +
> +	snprintf(fdinfo_path, sizeof(fdinfo_path), "/proc/self/fdinfo/%d", fd);
> +	fdinfo = open(fdinfo_path, O_RDONLY);
> +	if (fdinfo < 0) {
> +		pr_perror("Unable to open %s", fdinfo_path);
> +		return 1;
> +	}
> +
> +	buf = malloc(bsize);
> +	if (buf == NULL) {
> +		pr_perror("Unable to allocate a buffer");
> +		return 1;
> +	}
> +	size = 0;
> +	while (1) {
> +		ret = read(fdinfo, buf + size, bsize - 1 - size);
> +		if (ret == 0)
> +			break;
> +		if (ret == -1) {
> +			pr_perror("Unable to read %s", fdinfo_path);
> +			return 1;
> +		}
> +		size += ret;
> +		if (bsize - size < 4096)
> +			bsize += 4096;
> +		buf = realloc(buf, bsize);
> +		if (buf == NULL) {
> +			pr_perror("Unable to allocate a buffer");
> +			return 1;
> +		}
> +	}
> +	buf[size] = 0;
> +
> +	i = 0;
> +	for (p = buf - 1; p != NULL; p = strchr(p, '\n')) {
> +		char fl_flag[10], fl_type[15], fl_option[10], end[32];
> +		int fl_id, fl_owner, maj, min;
> +		unsigned long ino;
> +		unsigned long long start;
> +
> +		p++;
> +
> +		if (strncmp(p, "lock:", 5))
> +			continue;
> +		ret = sscanf(p, "lock:\t%d:%s %s %s %d %x:%x:%ld %lld %s",
> +				&fl_id, fl_flag, fl_type, fl_option,
> +				&fl_owner, &maj, &min, &ino,
> +				&start, end);
> +		if (ret != 10) {
> +			pr_perror("Unable to parse");
> +			fprintf(stderr, "%s\n", buf);
> +			return 1;
> +		}
> +		i++;
> +	}
> +
> +	close(fdinfo);
> +	close(fd);
> +
> +	if (i == FILE_SIZE)
> +		printf("PASS\n");

Look into using ksft framework for reporting pass/fail conditions.
Please see kselftest.h for the framework.

> +	else {
> +		fprintf(stderr, "%s\n", buf);
> +		return 1;
> +	}
> +
> +	free(buf);
> +
> +	return 0;
> +}
> 

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978
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