Re: [LTP] [PATCH v1] iocl11.c: New case check PROCMAP_QUERY ioctl() errnos

[Petr Vorel <pvorel@suse.cz>]

Hi Wei,

Thanks for writing new test. Generally LGTM.

Also, FYI upstream developer enhanced existing tools/testing/selftests/proc/proc-pid-vm.c
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=81510a0eaa6916c2fbb0b2639f3e617a296979a3
That might be a good source for real PROCMAP_QUERY testing.

Few common errors:

1) git commit subject contains typo:
iocl11 => ioctl11
Please remember to fix it.

2) Warning
$ make check-ioctl11
CHECK testcases/kernel/syscalls/ioctl/ioctl11.c
ioctl11.c:32:22: warning: Symbol 'q' has no prototype or library ('tst_') prefix. Should it be static?

3) EMFILE (Too many open files)
=> missing SAFE_FCLOSE(fp) before return start_addr;
# ./ioctl11 -i1200
ioctl11.c:149: TPASS: ioctl(fd, PROCMAP_QUERY, q) : E2BIG (7)
ioctl11.c:149: TPASS: ioctl(fd, PROCMAP_QUERY, q) : EINVAL (22)
ioctl11.c:101: TBROK: fopen(/proc/self/maps,r) failed: EMFILE (24)


ioctl11.c: In function ‘get_vm_start’:
ioctl11.c:113:1: warning: control reaches end of non-void function [-Wreturn-type]
  113 | }
      | ^

Other notes below.
...
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl11.c b/testcases/kernel/syscalls/ioctl/ioctl11.c
> new file mode 100644
> index 000000000..aef2105cc
> --- /dev/null
> +++ b/testcases/kernel/syscalls/ioctl/ioctl11.c
> @@ -0,0 +1,183 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (c) 2024 Wei Gao <wegao@suse.com>
Maybe update to 2025?

> + */
> +
> +/*\
> + * [Description]
> + *
> + * Test PROCMAP_QUERY ioctl() errnos:
> + *
> + * - EINVAL if q->size is too small
> + * - E2BIG if q->size is larger than page size
> + * - EINVAL on invalid q->flags
> + * - EINVAL if only one of q->vma_name_size and q->vma_name_addr is set
> + * - EINVAL if only one of q->build_id_size and q->build_id_addr is set
> + * - ENAMETOOLONG if build_id_size or name_buf_size is too small

What is name_buf_size? Do you mean vma_name_size?

I wonder whether pointing out in doc some of the relevant commits (6 commits
mentioned in "(FEATURED) ioctl()-based API to query VMAs from /proc/<pid>"
section in [1]) or just put [2] (or [3] would make sense.

[1] https://kernelnewbies.org/Linux_6.11#Memory_management
[2] https://kernelnewbies.org/Linux_6.11#Binary_interface_for_.2Fproc.2F.3Cpid.3E.2Fmaps
[3] https://lore.kernel.org/all/20240627170900.1672542-1-andrii@kernel.org/
ed5d583a88a9 ("fs/procfs: implement efficient VMA querying API for /proc/<pid>/maps")

> + */
> +
> +#include "config.h"
> +#include <stdlib.h>
Either <stdlib.h> is not needed or some of LTP headers probably adds it as it
builds without it.

> +#include <sys/ioctl.h>
<sys/ioctl.h> is not needed (loaded as part of lapi/ioctl.h.
https://github.com/linux-test-project/ltp/blob/master/doc/old/C-Test-API.asciidoc#lapi-headers

> +#include <errno.h>

> +#include <fnmatch.h>
Why this header? IMHO not needed.

> +#include "tst_test.h"
> +#include "tst_safe_stdio.h"

> +#include <sys/sysmacros.h>
Why this header? IMHO not needed.

very nit: Also I would first add system headers (these with <>) and then LTP
headers.  i.e. not mixing them.

> +#include <linux/fs.h>
> +#include "lapi/ioctl.h"
> +

#include "config.h"
#include <errno.h>
#include <linux/fs.h>
#include "tst_test.h"
#include "tst_safe_stdio.h"
#include "lapi/ioctl.h"

> +#define PROC_MAP_PATH "/proc/self/maps"
> +
> +struct procmap_query *q;
This should be static.

> +static int fd = -1;
> +static char buf[PATH_MAX];
> +static char small_buf[1];
> +
> +static void setup_normal(void);
> +static void setup_big_size(void);
> +
> +static struct tcase {
> +	uint64_t size;
> +	uint64_t query_addr;
> +	uint64_t query_flags;
> +	uint64_t vma_name_addr;
> +	uint32_t vma_name_size;
> +	uint64_t build_id_addr;
> +	uint32_t build_id_size;
> +	int exp_errno;
> +	void (*setup)(void);
> +} tcases[] = {
> +	{
> +		.size = 1,
> +		.exp_errno = EINVAL,
> +		.setup = setup_normal
> +	},
> +	{
> +		.exp_errno = E2BIG,
> +		.setup = setup_big_size
> +	},
> +	{
> +		.query_flags = -1,
> +		.exp_errno = EINVAL,
> +		.setup = setup_normal
> +	},
> +	{
> +		.vma_name_size = sizeof(buf),
> +		.exp_errno = EINVAL,
> +		.setup = setup_normal
> +	},
> +	{
> +		.vma_name_addr = (uint64_t)(unsigned long)buf,
> +		.exp_errno = EINVAL,
> +		.setup = setup_normal
> +	},
> +	{
> +		.build_id_size = sizeof(buf),
> +		.exp_errno = EINVAL,
> +		.setup = setup_normal
> +	},
> +	{
> +		.build_id_addr = (uint64_t)(unsigned long)buf,
> +		.exp_errno = EINVAL,
> +		.setup = setup_normal
> +	},
> +	{
> +		.vma_name_addr = (uint64_t)(unsigned long)small_buf,
> +		.vma_name_size = sizeof(small_buf),
> +		.exp_errno = ENAMETOOLONG,
> +		.setup = setup_normal
> +	},
> +	{
> +		.build_id_addr = (uint64_t)(unsigned long)small_buf,
> +		.build_id_size = sizeof(small_buf),
> +		.exp_errno = ENAMETOOLONG,
> +		.setup = setup_normal
> +	},
> +};
> +
> +static unsigned long get_vm_start(void)
> +{
> +	FILE *fp = SAFE_FOPEN(PROC_MAP_PATH, "r");
> +	char line[1024];
> +	unsigned long start_addr = 0;
> +
> +	if (fgets(line, sizeof(line), fp) != NULL) {
> +		if (sscanf(line, "%lx-", &start_addr) != 1)
> +			tst_brk(TFAIL, "parse maps file /proc/self/maps failed");
nit: Maybe "map not found in /proc/self/maps"?
Also, PROC_MAP_PATH will never change from /proc/self/maps, so it's probably safe
to use it hardcoded. But using just "map not found" would avoid hardcoded file.

Here you needs to also close fp.
> +		return start_addr;
> +	}
> +
> +	SAFE_FCLOSE(fp);
> +	tst_brk(TFAIL, "parse maps file /proc/self/maps failed");
> +}
> +
> +static void setup_normal(void)
> +{
> +	q->size = sizeof(*q);
> +	q->query_addr = (uint64_t)get_vm_start();
> +	q->query_flags = 0;
> +}
> +
> +static void setup_big_size(void)
> +{
> +	setup_normal();
IMHO content of setup_normal() should be moved to run(), before tc->setup().
Then all ".setup = setup_normal" could be removed.

> +	q->size = getpagesize() + 1;
> +}
> +
> +static void run(unsigned int n)
> +{
> +	struct tcase *tc = &tcases[n];
> +
> +	memset(q, 0, sizeof(*q));
> +
> +	tc->setup();
> +
> +	if (tc->size != 0)
> +		q->size = tc->size;

Spaces between each if would make code for me more readable.
> +	if (tc->query_flags != 0)
> +		q->query_flags = tc->query_flags;
> +	if (tc->vma_name_addr != 0)
> +		q->vma_name_addr = tc->vma_name_addr;
> +	if (tc->vma_name_size != 0)
> +		q->vma_name_size = tc->vma_name_size;
> +	if (tc->build_id_addr != 0)
> +		q->build_id_addr = tc->build_id_addr;
> +	if (tc->build_id_size != 0)
> +		q->build_id_size = tc->build_id_size;
> +
> +	TST_EXP_FAIL(ioctl(fd, PROCMAP_QUERY, q), tc->exp_errno);
> +}
> +
> +static void setup(void)
> +{
> +	struct procmap_query q = {};
> +
> +	fd = SAFE_OPEN(PROC_MAP_PATH, O_RDONLY);
> +
> +	if (tst_kvercmp(6, 11, 0) < 0) {
If you reverse the condition code is more compact.
> +		TEST(ioctl(fd, PROCMAP_QUERY, q));
> +
> +		if ((TST_RET == -1) && (TST_ERR == ENOTTY))
Brackets between && are not needed.
> +			tst_brk(TCONF,
> +				"This system does not provide support for ioctl(PROCMAP_QUERY)");


	if (tst_kvercmp(6, 11, 0) >= 0)
		return;

	TEST(ioctl(fd, PROCMAP_QUERY, q));
	if (TST_RET == -1 && TST_ERR == ENOTTY) {
		tst_brk(TCONF,
			"This system does not provide support for ioctl(PROCMAP_QUERY)");
	}

> +	}
> +
Please remove this blank line ^.
> +}

Kind regards,
Petr

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