tools/testing/selftests/ftrace/poll.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/ftrace/poll.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/ftrace/poll.c
Extension
.c
Size
1356 bytes
Lines
75
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.

Dependency Surface

Detected Declarations

Annotated Snippet

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) {
		perror("poll");
		return -1;
	}
	close(pfd.fd);

	/* If timeout happned (ret == 0), exit code is 1 */
	if (ret == 0)
		return 1;

	return 0;
}

Annotation

Implementation Notes