tools/testing/selftests/kcmp/kcmp_test.c

File Facts

System

Linux kernel

Corpus path

tools/testing/selftests/kcmp/kcmp_test.c

Extension

.c

Size

3619 bytes

Lines

169

Domain

Support Tooling And Documentation

Bucket

tools

Inferred role

Support Tooling And Documentation: implementation source

Status

source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• stdio.h
• stdlib.h
• signal.h
• limits.h
• unistd.h
• errno.h
• string.h
• fcntl.h
• linux/unistd.h
• linux/kcmp.h
• sys/syscall.h
• sys/types.h
• sys/stat.h
• sys/wait.h
• sys/epoll.h
• kselftest.h

Detected Declarations

• function sys_kcmp
• function main

Annotated Snippet

if (fd2 < 0) {
			perror("Can't open file");
			ksft_exit_fail();
		}

		/* An example of output and arguments */
		printf("pid1: %6d pid2: %6d FD: %2ld FILES: %2ld VM: %2ld "
		       "FS: %2ld SIGHAND: %2ld IO: %2ld SYSVSEM: %2ld "
		       "INV: %2ld\n",
		       pid1, pid2,
		       sys_kcmp(pid1, pid2, KCMP_FILE,		fd1, fd2),
		       sys_kcmp(pid1, pid2, KCMP_FILES,		0, 0),
		       sys_kcmp(pid1, pid2, KCMP_VM,		0, 0),
		       sys_kcmp(pid1, pid2, KCMP_FS,		0, 0),
		       sys_kcmp(pid1, pid2, KCMP_SIGHAND,	0, 0),
		       sys_kcmp(pid1, pid2, KCMP_IO,		0, 0),
		       sys_kcmp(pid1, pid2, KCMP_SYSVSEM,	0, 0),

			/* This one should fail */
		       sys_kcmp(pid1, pid2, KCMP_TYPES + 1,	0, 0));

		/* This one should return same fd */
		ret = sys_kcmp(pid1, pid2, KCMP_FILE, fd1, fd1);
		if (ret) {
			printf("FAIL: 0 expected but %d returned (%s)\n",
				ret, strerror(errno));
			ksft_inc_fail_cnt();
			ret = -1;
		} else {
			printf("PASS: 0 returned as expected\n");
			ksft_inc_pass_cnt();
		}

		/* Compare with self */
		ret = sys_kcmp(pid1, pid1, KCMP_VM, 0, 0);
		if (ret) {
			printf("FAIL: 0 expected but %d returned (%s)\n",
				ret, strerror(errno));
			ksft_inc_fail_cnt();
			ret = -1;
		} else {
			printf("PASS: 0 returned as expected\n");
			ksft_inc_pass_cnt();
		}

		/* Compare epoll target */
		epoll_slot = (struct kcmp_epoll_slot) {
			.efd	= epollfd,
			.tfd	= duped_num,
			.toff	= 0,
		};
		ret = sys_kcmp(pid1, pid1, KCMP_EPOLL_TFD, pipefd[1],
			       (unsigned long)(void *)&epoll_slot);
		if (ret) {
			printf("FAIL: 0 expected but %d returned (%s)\n",
				ret, strerror(errno));
			ksft_inc_fail_cnt();
			ret = -1;
		} else {
			printf("PASS: 0 returned as expected\n");
			ksft_inc_pass_cnt();
		}


		if (ret)
			ksft_exit_fail();
		else
			ksft_exit_pass();
	}

	waitpid(pid2, &status, P_ALL);

	return 0;
}

Annotation

• Immediate include surface: `stdio.h`, `stdlib.h`, `signal.h`, `limits.h`, `unistd.h`, `errno.h`, `string.h`, `fcntl.h`.
• Detected declarations: `function sys_kcmp`, `function main`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.