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722c62827b
The major contribution here is completely re-worked breakpoint hit/recoil handling. This work fixes #4907 and lays the ground work for future native debugger improvements (multi-threading, etc). * Give a human friendly type to enums * Change many wait functions to return RDebugReasonType * Better return checking (from r_debug_reg_sync, r_bp_restore) * Optimized register synchronization * Lots of comments and whitespace changes * Improved inferior death detection Handle EXIT_PID events differently than DEAD process events * Move breakpoint/recoil handling to wait/cont/step Rather than handing breakpoint related things inside cmd_debug.c, do that inside the r_debug API functions. This seems like the most logical place for it to live since it should apply to just about any platform/architecture. This also centralizes calling into "cmd.bp" handling via the CoreBind callback. * Track how the caller wishes to continue It turns out that handling break point recoils is very complicated. The ptrace API on Linux returns SIGTRAP for just about every type of operation (not just breakpoints getting hit). Add the "recoil_mode" flag to indicate whether we are single-stepping or continuing and whether or not we are inside the recoil. * Proper handling for swstep=true Since r_debug_step_soft calls r_debug_continue, it's already hitting the recoil case there. Move the recoil handling from r_debug_step to r_debug_step_hard only. For the swstep=true case, special handling is required inside r_debug_recoil. By resetting all of the breakpoints except the one we just hit, we ensure we can step the original instruction and hit the new swstep breakpoint. Add a new bp function called r_bp_restore_except to do this. To make matters worse, we cannot use a BreakpointItem pointer because that leads to a use-after-free condition. Instead, we the breakpoint address instead. Now breakpoints should work regardless of the swtep setting. * Always call the recoil before continuing Some callers of r_debug_continue might not have ever inserted any breakpoints before. If we don't restore breakpoints before each call to the underlying continue we won't hit them. * Hide software step breakpoint events from the user When a breakpoint even happens due to a software-step, hide it from the user. They aren't really breakpoints as far as they are concerned. * Improve process exit handling on Linux There are three types of process exiting events on Linux: 1. PTRACE_EVENT_EXIT occurs just before a process exits. It's not possible to prevent it from exiting, but it can be used to inspect the pre-exit state. 2. The process can exit for a variety of reasons and we can notice when we call waitpid(2). 3. The process could die randomly on us :-/ On Windows, h->wait will return R_DEBUG_REASON_EXIT_PID, but it's more likely on Linux to find out the process is already dead. * Check more bits within waitpid status We can often make a decision about what happened strictly by looking at the status returned from waitpid. In other cases, we need to call r_debug_handle_signals. If we reach the end of this function without knowing what happened, consider it an error. |
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| .. | ||
| p | ||
| bp.c | ||
| io.c | ||
| Jamroot | ||
| Makefile | ||
| parser.c | ||
| parser.h | ||
| plugin.c | ||
| README | ||
| traptrace.c | ||
| watch.c | ||
libr.bp
=======
Breakpoint API
- Manages list of defined breakpoints
- Determines if a stop is caused by a breakpoint
- Owns a database of multiple types of breakpoints
- arch and os based ones
- Supports endianness
- r_bp_get should return a buffer and a length
- Manages conditional breakpoints expressions
- Types of breakpoints
- software (traps)
- conditional traps
- hardware (registers)
- mmu (changes page protections)
- All non-native operations are translated into evaluable expressions
by other modules. Like changing register values and so on
- Do we should place some callbacks for this kind of ops?
- We need to make this work also remotely
- r_debug can handle the remoteness of the debugger backend.
- r_io can do it also
- Watchpoints and its exception should be handled here
- watchpoint expressions should be handled by using the r_num stuff
- Hardware breakpoints require access to registers, or pid/tid
this is... the debugger backend. For those, the debugger backend
should fill a callback to manage them.
- if the debugger breakpoint handler does not manages the breakpoint
type, r_bp must do it with r_io storing and loading bp bytes.
* Do we need the plugin API to define new breakpoints and so on?