tools/testing/selftests/breakpoints/breakpoint_test.c

File Facts

System

Linux kernel

Corpus path

tools/testing/selftests/breakpoints/breakpoint_test.c

Extension

.c

Size

7802 bytes

Lines

410

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

• sys/ptrace.h
• unistd.h
• stddef.h
• sys/user.h
• stdio.h
• stdlib.h
• signal.h
• sys/types.h
• sys/wait.h
• errno.h
• string.h
• kselftest.h

Detected Declarations

• function set_breakpoint_addr
• function toggle_breakpoint
• function dummy_func
• function check_trapped
• function write_var
• function read_var
• function trigger_tests
• function check_success
• function launch_instruction_breakpoints
• function launch_watchpoints
• function launch_tests
• function main

Annotated Snippet

static void dummy_func(void) { }
static void dummy_func1(void) { }
static void dummy_func2(void) { }
static void dummy_func3(void) { }

static void (*dummy_funcs[])(void) = {
	dummy_func,
	dummy_func1,
	dummy_func2,
	dummy_func3,
};

static int trapped;

static void check_trapped(void)
{
	/*
	 * If we haven't trapped, wake up the parent
	 * so that it notices the failure.
	 */
	if (!trapped)
		kill(getpid(), SIGUSR1);
	trapped = 0;

	nr_tests++;
}

static void write_var(int len)
{
	char *pcval; short *psval; int *pival; long long *plval;
	int i;

	for (i = 0; i < 4; i++) {
		switch (len) {
		case 1:
			pcval = (char *)&dummy_var[i];
			*pcval = 0xff;
			break;
		case 2:
			psval = (short *)&dummy_var[i];
			*psval = 0xffff;
			break;
		case 4:
			pival = (int *)&dummy_var[i];
			*pival = 0xffffffff;
			break;
		case 8:
			plval = (long long *)&dummy_var[i];
			*plval = 0xffffffffffffffffLL;
			break;
		}
		check_trapped();
	}
}

static void read_var(int len)
{
	char cval; short sval; int ival; long long lval;
	int i;

	for (i = 0; i < 4; i++) {
		switch (len) {
		case 1:
			cval = *(char *)&dummy_var[i];
			break;
		case 2:
			sval = *(short *)&dummy_var[i];
			break;
		case 4:
			ival = *(int *)&dummy_var[i];
			break;
		case 8:
			lval = *(long long *)&dummy_var[i];
			break;
		}
		check_trapped();
	}
}

/*
 * Do the r/w/x accesses to trigger the breakpoints. And run
 * the usual traps.
 */
static void trigger_tests(void)
{
	int len, local, global, i;
	char val;
	int ret;

	ret = ptrace(PTRACE_TRACEME, 0, NULL, 0);

Annotation

• Immediate include surface: `sys/ptrace.h`, `unistd.h`, `stddef.h`, `sys/user.h`, `stdio.h`, `stdlib.h`, `signal.h`, `sys/types.h`.
• Detected declarations: `function set_breakpoint_addr`, `function toggle_breakpoint`, `function dummy_func`, `function check_trapped`, `function write_var`, `function read_var`, `function trigger_tests`, `function check_success`, `function launch_instruction_breakpoints`, `function launch_watchpoints`.
• 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.