840bb0acb5
The unwind subsystem uses the mmap_cache subsystem even it uses
unwind-libdw as backend. unwind-libdw doesn't need the full set of the
mmap_cache subsystem; libdw has a feature for caching a memory
mapping.
This commit does three things.
(1) Make the unwind subsystem not use the mmap_cache subsystem.
The unwind subsystem never concern the memory mapping of the target.
It becomes a thin layer.
(2) Make unwind-libunwind use the mmap_cache subsystem directly.
(3) Make unwind-libdw use the mmap_notify subsystem to know when it
should call dwfl_linux_proc_report/dwfl_report_end for updating the
cache.
Here is a subsystem structure that this patch
introduces:
+-------------------------------------+
| unwind subsys |
+------------------+------------------+
| unwind-libunwind | unwind-libdw |
+------------------+------------------+
| mmap_cache | |
+------------------+ |
| mmap_notify |
+-------------------------------------+
| syscall |
+-------------------------------------+
mmap/munmap/mprotect/brk...
* unwind.c: Don't include "mmap_cache.h".
(unwind_init): Don't call mmap_cache_enable.
(unwind_tcb_print, unwind_tcb_capture): Don't call mmap_cache related
functions, just invoke unwinder.tcb_walk.
* unwind.h (struct unwind_unwinder_t): Remove tcb_flush_cache field.
* unwind-libdw.c: Include "mmap_notify.h" instead of "mmap_cache.h".
(struct ctx): Add last_proc_updating field to record the generation
of memory mapping that is cached by dwfl_linux_proc_report
and dwfl_report_end.
(mapping_generation): A variable counting how many times the memory
mapping of targets has been changed.
(updating_mapping_generation): New utility function for updating
mapping_generation.
(init): New function for registering updating_mapping_generation
in the mmap_notify subsystem as a callback function.
(tcb_init): Initialize ctx::last_proc_updating.
(tcb_flush_cache): Rename to flush_cache_maybe. Rebuild the cache data
only if the data is stale.
(tcb_walk): Call flush_cache_maybe for avoiding referring staled cache data.
(unwinder): Set init function, remove tcb_flush_cache field.
* unwind-libunwind.c (init): Enable the mmap_cache subsystem.
(tcb_walk): Call mmap_cache_rebuild_if_invalid and unw_flush_cache for
updating the cache of the memory mapping before walking the stack.
(tcb_walk): Rename to walk.
(unwinder): Remove tcb_flush_cache field.
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
71 lines
2.5 KiB
C
71 lines
2.5 KiB
C
/*
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* Unwinder backends interface.
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*
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* Copyright (c) 2013 Luca Clementi <luca.clementi@gmail.com>
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* Copyright (c) 2013-2018 The strace developers.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef STRACE_UNWIND_H
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#define STRACE_UNWIND_H
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#include "defs.h"
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/*
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* Type used in stacktrace walker.
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*/
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/* This storage be enough large to store unw_word_t. */
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typedef unsigned long unwind_function_offset_t;
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typedef void (*unwind_call_action_fn)(void *data,
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const char *binary_filename,
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const char *symbol_name,
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unwind_function_offset_t function_offset,
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unsigned long true_offset);
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typedef void (*unwind_error_action_fn)(void *data,
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const char *error,
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unsigned long true_offset);
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struct unwind_unwinder_t {
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const char *name;
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/* Initialize the unwinder. */
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void (*init)(void);
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/* Make/destroy the context data attached to tcb. */
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void * (*tcb_init)(struct tcb *);
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void (*tcb_fin)(struct tcb *);
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/* Walk the stack. */
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void (*tcb_walk)(struct tcb *,
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unwind_call_action_fn,
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unwind_error_action_fn,
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void *);
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};
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extern const struct unwind_unwinder_t unwinder;
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#endif /* !STRACE_UNWIND_H */
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