tools/testing/selftests/proc/proc-subset-pid.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/proc/proc-subset-pid.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/proc/proc-subset-pid.c
Extension
.c
Size
2844 bytes
Lines
122
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

if (errno == ENOSYS || errno == EPERM) {
			exit(4);
		}
		exit(1);
	}
	if (mount(NULL, "/", NULL, MS_PRIVATE|MS_REC, NULL) == -1) {
		exit(1);
	}
	if (mount(NULL, "/proc", "proc", 0, "subset=pid") == -1) {
		exit(1);
	}
}

static bool string_is_pid(const char *s)
{
	while (1) {
		switch (*s++) {
		case '0':case '1':case '2':case '3':case '4':
		case '5':case '6':case '7':case '8':case '9':
			continue;

		case '\0':
			return true;

		default:
			return false;
		}
	}
}

int main(void)
{
	make_private_proc();

	DIR *d = opendir("/proc");
	assert(d);

	struct dirent *de;

	bool dot = false;
	bool dot_dot = false;
	bool self = false;
	bool thread_self = false;

	while ((de = readdir(d))) {
		if (streq(de->d_name, ".")) {
			assert(!dot);
			dot = true;
			assert(de->d_type == DT_DIR);
		} else if (streq(de->d_name, "..")) {
			assert(!dot_dot);
			dot_dot = true;
			assert(de->d_type == DT_DIR);
		} else if (streq(de->d_name, "self")) {
			assert(!self);
			self = true;
			assert(de->d_type == DT_LNK);
		} else if (streq(de->d_name, "thread-self")) {
			assert(!thread_self);
			thread_self = true;
			assert(de->d_type == DT_LNK);
		} else {
			if (!string_is_pid(de->d_name)) {
				fprintf(stderr, "d_name '%s'\n", de->d_name);
				assert(0);
			}
			assert(de->d_type == DT_DIR);
		}
	}

	char c;
	int rv = readlink("/proc/cpuinfo", &c, 1);
	assert(rv == -1 && errno == ENOENT);

	int fd = open("/proc/cpuinfo", O_RDONLY);
	assert(fd == -1 && errno == ENOENT);

	return 0;
}

Annotation

Implementation Notes