f0c5872637
Keep track of whether memory maps are readable. Use the information in try_get_word to try to avoid accidentally dereferencing an invalid pointer within the current process. (Note that I haven't ever seen that happen during normal unwinding, but it pays to be a little more careful.) Refactored try_get_word a little to make it easier to pass it the needed state for validation checks by way of a little memory_t struct. Improved how the memory map for the current process is cached. This is important because we need up to date information about readable maps. Use a 5 second cache expiration. Improved the PC -> LR fallback logic in the unwinder so we can eke out an extra frame sometimes. Fixed a bug reading ELF program headers. The phnum & phentsize fields are half-words. We were incorrectly interpreting phnum as a whole word. Used android_atomic_* operations carefully in the unwinder to prevent possible memory races between the dumper and the dumpee. This was highly unlikely (or even impossible due to the presence of other barriers along the way) but the code is clearer now about its invariants. Fixed a bug in debuggerd where the pid was being passed to have its stack dump taken instead of the tid, resulting in short stacks because ptrace couldn't read the data if pid != tid. Did a full sweep to ensure that we use pid / tid correctly everywhere. Ported old code from debuggerd to rewind the program counter back one instruction so that it points to the branch instruction itself instead of the return address. Change-Id: Icc4eb08320052975a4ae7f0f5f0ac9308a2d33d7
72 lines
2 KiB
C
72 lines
2 KiB
C
/* system/debuggerd/utility.h
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**
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** Copyright 2008, The Android Open Source Project
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**
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** Licensed under the Apache License, Version 2.0 (the "License");
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** you may not use this file except in compliance with the License.
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** You may obtain a copy of the License at
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**
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** http://www.apache.org/licenses/LICENSE-2.0
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**
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** Unless required by applicable law or agreed to in writing, software
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** distributed under the License is distributed on an "AS IS" BASIS,
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** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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** See the License for the specific language governing permissions and
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** limitations under the License.
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*/
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#ifndef _DEBUGGERD_UTILITY_H
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#define _DEBUGGERD_UTILITY_H
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#include <stddef.h>
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#include <stdbool.h>
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#include <sys/types.h>
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#include <corkscrew/backtrace.h>
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/* Log information onto the tombstone. */
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void _LOG(int tfd, bool in_tombstone_only, const char *fmt, ...)
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__attribute__ ((format(printf, 3, 4)));
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#define LOG(fmt...) _LOG(-1, 0, fmt)
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/* Set to 1 for normal debug traces */
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#if 0
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#define XLOG(fmt...) _LOG(-1, 0, fmt)
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#else
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#define XLOG(fmt...) do {} while(0)
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#endif
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/* Set to 1 for chatty debug traces. Includes all resolved dynamic symbols */
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#if 0
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#define XLOG2(fmt...) _LOG(-1, 0, fmt)
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#else
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#define XLOG2(fmt...) do {} while(0)
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#endif
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/*
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* Returns true if the specified signal has an associated address.
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* (i.e. it sets siginfo_t.si_addr).
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*/
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bool signal_has_address(int sig);
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/*
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* Dumps the backtrace and contents of the stack.
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*/
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void dump_backtrace_and_stack(const ptrace_context_t* context, int tfd, pid_t tid, bool at_fault);
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/*
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* Dumps a few bytes of memory, starting a bit before and ending a bit
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* after the specified address.
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*/
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void dump_memory(int tfd, pid_t tid, uintptr_t addr, bool at_fault);
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/*
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* If this isn't clearly a null pointer dereference, dump the
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* /proc/maps entries near the fault address.
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*
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* This only makes sense to do on the thread that crashed.
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*/
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void dump_nearby_maps(const ptrace_context_t* context, int tfd, pid_t tid);
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#endif // _DEBUGGERD_UTILITY_H
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