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-rw-r--r--include/corkscrew/backtrace.h102
-rw-r--r--include/corkscrew/demangle.h42
-rw-r--r--include/corkscrew/map_info.h54
-rw-r--r--include/corkscrew/ptrace.h97
-rw-r--r--include/corkscrew/symbol_table.h58
-rw-r--r--libcorkscrew/Android.mk41
-rw-r--r--libcorkscrew/MODULE_LICENSE_APACHE20
-rw-r--r--libcorkscrew/NOTICE190
-rw-r--r--libcorkscrew/arch-arm/backtrace-arm.c516
-rw-r--r--libcorkscrew/arch-arm/ptrace-arm.c65
-rw-r--r--libcorkscrew/backtrace-arch.h41
-rw-r--r--libcorkscrew/backtrace-helper.c40
-rw-r--r--libcorkscrew/backtrace-helper.h43
-rw-r--r--libcorkscrew/backtrace.c205
-rw-r--r--libcorkscrew/demangle.c35
-rw-r--r--libcorkscrew/map_info.c112
-rw-r--r--libcorkscrew/ptrace-arch.h47
-rw-r--r--libcorkscrew/ptrace.c134
-rw-r--r--libcorkscrew/symbol_table.c204
19 files changed, 2026 insertions, 0 deletions
diff --git a/include/corkscrew/backtrace.h b/include/corkscrew/backtrace.h
new file mode 100644
index 0000000..cecb13d
--- /dev/null
+++ b/include/corkscrew/backtrace.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* A stack unwinder. */
+
+#ifndef _CORKSCREW_BACKTRACE_H
+#define _CORKSCREW_BACKTRACE_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <sys/types.h>
+#include <corkscrew/ptrace.h>
+#include <corkscrew/map_info.h>
+#include <corkscrew/symbol_table.h>
+
+/*
+ * Describes a single frame of a backtrace.
+ */
+typedef struct {
+ uintptr_t absolute_pc; /* absolute PC offset */
+ uintptr_t stack_top; /* top of stack for this frame */
+ size_t stack_size; /* size of this stack frame */
+} backtrace_frame_t;
+
+/*
+ * Describes the symbols associated with a backtrace frame.
+ */
+typedef struct {
+ uintptr_t relative_pc; /* relative PC offset from the start of the library,
+ or the absolute PC if the library is unknown */
+ const map_info_t* map_info; /* memory map of the library, or NULL if unknown */
+ const char* name; /* symbol name, or NULL if unknown */
+ char* demangled_name; /* demangled symbol name, or NULL if unknown */
+} backtrace_symbol_t;
+
+/*
+ * Unwinds the call stack for the current thread of execution.
+ * Populates the backtrace array with the program counters from the call stack.
+ * Returns the number of frames collected, or -1 if an error occurred.
+ */
+ssize_t unwind_backtrace(backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth);
+
+/*
+ * Unwinds the call stack for a thread within this process.
+ * Populates the backtrace array with the program counters from the call stack.
+ * Returns the number of frames collected, or -1 if an error occurred.
+ *
+ * The task is briefly suspended while the backtrace is being collected.
+ */
+ssize_t unwind_backtrace_thread(pid_t tid, backtrace_frame_t* backtrace,
+ size_t ignore_depth, size_t max_depth);
+
+/*
+ * Unwinds the call stack of a task within a remote process using ptrace().
+ * Populates the backtrace array with the program counters from the call stack.
+ * Returns the number of frames collected, or -1 if an error occurred.
+ */
+ssize_t unwind_backtrace_ptrace(pid_t tid, const ptrace_context_t* context,
+ backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth);
+
+/*
+ * Gets the symbols for each frame of a backtrace.
+ * The symbols array must be big enough to hold one symbol record per frame.
+ * The symbols must later be freed using free_backtrace_symbols.
+ */
+void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
+ backtrace_symbol_t* backtrace_symbols);
+
+/*
+ * Gets the symbols for each frame of a backtrace from a remote process.
+ * The symbols array must be big enough to hold one symbol record per frame.
+ * The symbols must later be freed using free_backtrace_symbols.
+ */
+void get_backtrace_symbols_ptrace(const ptrace_context_t* context,
+ const backtrace_frame_t* backtrace, size_t frames,
+ backtrace_symbol_t* backtrace_symbols);
+
+/*
+ * Frees the storage associated with backtrace symbols.
+ */
+void free_backtrace_symbols(backtrace_symbol_t* backtrace_symbols, size_t frames);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_BACKTRACE_H
diff --git a/include/corkscrew/demangle.h b/include/corkscrew/demangle.h
new file mode 100644
index 0000000..04b0225
--- /dev/null
+++ b/include/corkscrew/demangle.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* C++ symbol name demangling. */
+
+#ifndef _CORKSCREW_DEMANGLE_H
+#define _CORKSCREW_DEMANGLE_H
+
+#include <sys/types.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Demangles a C++ symbol name.
+ * If name is NULL or if the name cannot be demangled, returns NULL.
+ * Otherwise, returns a newly allocated string that contains the demangled name.
+ *
+ * The caller must free the returned string using free().
+ */
+char* demangle_symbol_name(const char* name);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_DEMANGLE_H
diff --git a/include/corkscrew/map_info.h b/include/corkscrew/map_info.h
new file mode 100644
index 0000000..a1c344f
--- /dev/null
+++ b/include/corkscrew/map_info.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Process memory map. */
+
+#ifndef _CORKSCREW_MAP_INFO_H
+#define _CORKSCREW_MAP_INFO_H
+
+#include <sys/types.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct map_info {
+ struct map_info* next;
+ uintptr_t start;
+ uintptr_t end;
+ bool is_executable;
+ void* data; // arbitrary data associated with the map by the user, initially NULL
+ char name[];
+} map_info_t;
+
+/* Loads memory map from /proc/<tid>/maps. */
+map_info_t* load_map_info_list(pid_t tid);
+
+/* Frees memory map. */
+void free_map_info_list(map_info_t* milist);
+
+/* Finds the memory map that contains the specified address. */
+const map_info_t* find_map_info(const map_info_t* milist, uintptr_t addr);
+
+/* Gets the memory map for this process. (result is cached) */
+const map_info_t* my_map_info_list();
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_MAP_INFO_H
diff --git a/include/corkscrew/ptrace.h b/include/corkscrew/ptrace.h
new file mode 100644
index 0000000..6acf9eb
--- /dev/null
+++ b/include/corkscrew/ptrace.h
@@ -0,0 +1,97 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Useful ptrace() utility functions. */
+
+#ifndef _CORKSCREW_PTRACE_H
+#define _CORKSCREW_PTRACE_H
+
+#include <corkscrew/map_info.h>
+#include <corkscrew/symbol_table.h>
+
+#include <sys/types.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Stores information about a process that is used for several different
+ * ptrace() based operations. */
+typedef struct {
+ map_info_t* map_info_list;
+} ptrace_context_t;
+
+#if __i386__
+/* ptrace() register context. */
+typedef struct pt_regs_x86 {
+ uint32_t ebx;
+ uint32_t ecx;
+ uint32_t edx;
+ uint32_t esi;
+ uint32_t edi;
+ uint32_t ebp;
+ uint32_t eax;
+ uint32_t xds;
+ uint32_t xes;
+ uint32_t xfs;
+ uint32_t xgs;
+ uint32_t orig_eax;
+ uint32_t eip;
+ uint32_t xcs;
+ uint32_t eflags;
+ uint32_t esp;
+ uint32_t xss;
+} pt_regs_x86_t;
+#endif
+
+/*
+ * Reads a word of memory safely.
+ * Uses ptrace() if tid >= 0, local memory otherwise.
+ * Returns false if the word could not be read.
+ */
+bool try_get_word(pid_t tid, uintptr_t ptr, uint32_t* out_value);
+
+/*
+ * Loads information needed for examining a remote process using ptrace().
+ * The caller must already have successfully attached to the process
+ * using ptrace().
+ *
+ * The context can be used for any threads belonging to that process
+ * assuming ptrace() is attached to them before performing the actual
+ * unwinding. The context can continue to be used to decode backtraces
+ * even after ptrace() has been detached from the process.
+ */
+ptrace_context_t* load_ptrace_context(pid_t pid);
+
+/*
+ * Frees a ptrace context.
+ */
+void free_ptrace_context(ptrace_context_t* context);
+
+/*
+ * Finds a symbol using ptrace.
+ * Returns the containing map and information about the symbol, or
+ * NULL if one or the other is not available.
+ */
+void find_symbol_ptrace(const ptrace_context_t* context,
+ uintptr_t addr, const map_info_t** out_map_info, const symbol_t** out_symbol);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_PTRACE_H
diff --git a/include/corkscrew/symbol_table.h b/include/corkscrew/symbol_table.h
new file mode 100644
index 0000000..020c8b8
--- /dev/null
+++ b/include/corkscrew/symbol_table.h
@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef _CORKSCREW_SYMBOL_TABLE_H
+#define _CORKSCREW_SYMBOL_TABLE_H
+
+#include <sys/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+typedef struct {
+ uintptr_t start;
+ uintptr_t end;
+ char* name;
+} symbol_t;
+
+typedef struct {
+ symbol_t* symbols;
+ size_t num_symbols;
+} symbol_table_t;
+
+/*
+ * Loads a symbol table from a given file.
+ * Returns NULL on error.
+ */
+symbol_table_t* load_symbol_table(const char* filename);
+
+/*
+ * Frees a symbol table.
+ */
+void free_symbol_table(symbol_table_t* table);
+
+/*
+ * Finds a symbol associated with an address in the symbol table.
+ * Returns NULL if not found.
+ */
+const symbol_t* find_symbol(const symbol_table_t* table, uintptr_t addr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_SYMBOL_TABLE_H
diff --git a/libcorkscrew/Android.mk b/libcorkscrew/Android.mk
new file mode 100644
index 0000000..08432ef
--- /dev/null
+++ b/libcorkscrew/Android.mk
@@ -0,0 +1,41 @@
+# Copyright (C) 2011 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+LOCAL_PATH:= $(call my-dir)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := \
+ backtrace.c \
+ backtrace-helper.c \
+ demangle.c \
+ map_info.c \
+ ptrace.c \
+ symbol_table.c
+
+ifeq ($(TARGET_ARCH),arm)
+LOCAL_SRC_FILES += \
+ arch-arm/backtrace-arm.c \
+ arch-arm/ptrace-arm.c
+LOCAL_CFLAGS += -DCORKSCREW_HAVE_ARCH -DCORKSCREW_HAVE_LIBIBERTY
+LOCAL_LDFLAGS += -liberty
+endif
+
+LOCAL_SHARED_LIBRARIES += libdl libcutils
+
+LOCAL_CFLAGS += -std=gnu99 -Werror
+LOCAL_MODULE := libcorkscrew
+LOCAL_MODULE_TAGS := optional
+
+include $(BUILD_SHARED_LIBRARY)
diff --git a/libcorkscrew/MODULE_LICENSE_APACHE2 b/libcorkscrew/MODULE_LICENSE_APACHE2
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/libcorkscrew/MODULE_LICENSE_APACHE2
diff --git a/libcorkscrew/NOTICE b/libcorkscrew/NOTICE
new file mode 100644
index 0000000..becc120
--- /dev/null
+++ b/libcorkscrew/NOTICE
@@ -0,0 +1,190 @@
+
+ Copyright (c) 2011, The Android Open Source Project
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License.
+
+
+ Apache License
+ Version 2.0, January 2004
+ http://www.apache.org/licenses/
+
+ TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+ 1. Definitions.
+
+ "License" shall mean the terms and conditions for use, reproduction,
+ and distribution as defined by Sections 1 through 9 of this document.
+
+ "Licensor" shall mean the copyright owner or entity authorized by
+ the copyright owner that is granting the License.
+
+ "Legal Entity" shall mean the union of the acting entity and all
+ other entities that control, are controlled by, or are under common
+ control with that entity. For the purposes of this definition,
+ "control" means (i) the power, direct or indirect, to cause the
+ direction or management of such entity, whether by contract or
+ otherwise, or (ii) ownership of fifty percent (50%) or more of the
+ outstanding shares, or (iii) beneficial ownership of such entity.
+
+ "You" (or "Your") shall mean an individual or Legal Entity
+ exercising permissions granted by this License.
+
+ "Source" form shall mean the preferred form for making modifications,
+ including but not limited to software source code, documentation
+ source, and configuration files.
+
+ "Object" form shall mean any form resulting from mechanical
+ transformation or translation of a Source form, including but
+ not limited to compiled object code, generated documentation,
+ and conversions to other media types.
+
+ "Work" shall mean the work of authorship, whether in Source or
+ Object form, made available under the License, as indicated by a
+ copyright notice that is included in or attached to the work
+ (an example is provided in the Appendix below).
+
+ "Derivative Works" shall mean any work, whether in Source or Object
+ form, that is based on (or derived from) the Work and for which the
+ editorial revisions, annotations, elaborations, or other modifications
+ represent, as a whole, an original work of authorship. For the purposes
+ of this License, Derivative Works shall not include works that remain
+ separable from, or merely link (or bind by name) to the interfaces of,
+ the Work and Derivative Works thereof.
+
+ "Contribution" shall mean any work of authorship, including
+ the original version of the Work and any modifications or additions
+ to that Work or Derivative Works thereof, that is intentionally
+ submitted to Licensor for inclusion in the Work by the copyright owner
+ or by an individual or Legal Entity authorized to submit on behalf of
+ the copyright owner. For the purposes of this definition, "submitted"
+ means any form of electronic, verbal, or written communication sent
+ to the Licensor or its representatives, including but not limited to
+ communication on electronic mailing lists, source code control systems,
+ and issue tracking systems that are managed by, or on behalf of, the
+ Licensor for the purpose of discussing and improving the Work, but
+ excluding communication that is conspicuously marked or otherwise
+ designated in writing by the copyright owner as "Not a Contribution."
+
+ "Contributor" shall mean Licensor and any individual or Legal Entity
+ on behalf of whom a Contribution has been received by Licensor and
+ subsequently incorporated within the Work.
+
+ 2. Grant of Copyright License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ copyright license to reproduce, prepare Derivative Works of,
+ publicly display, publicly perform, sublicense, and distribute the
+ Work and such Derivative Works in Source or Object form.
+
+ 3. Grant of Patent License. Subject to the terms and conditions of
+ this License, each Contributor hereby grants to You a perpetual,
+ worldwide, non-exclusive, no-charge, royalty-free, irrevocable
+ (except as stated in this section) patent license to make, have made,
+ use, offer to sell, sell, import, and otherwise transfer the Work,
+ where such license applies only to those patent claims licensable
+ by such Contributor that are necessarily infringed by their
+ Contribution(s) alone or by combination of their Contribution(s)
+ with the Work to which such Contribution(s) was submitted. If You
+ institute patent litigation against any entity (including a
+ cross-claim or counterclaim in a lawsuit) alleging that the Work
+ or a Contribution incorporated within the Work constitutes direct
+ or contributory patent infringement, then any patent licenses
+ granted to You under this License for that Work shall terminate
+ as of the date such litigation is filed.
+
+ 4. Redistribution. You may reproduce and distribute copies of the
+ Work or Derivative Works thereof in any medium, with or without
+ modifications, and in Source or Object form, provided that You
+ meet the following conditions:
+
+ (a) You must give any other recipients of the Work or
+ Derivative Works a copy of this License; and
+
+ (b) You must cause any modified files to carry prominent notices
+ stating that You changed the files; and
+
+ (c) You must retain, in the Source form of any Derivative Works
+ that You distribute, all copyright, patent, trademark, and
+ attribution notices from the Source form of the Work,
+ excluding those notices that do not pertain to any part of
+ the Derivative Works; and
+
+ (d) If the Work includes a "NOTICE" text file as part of its
+ distribution, then any Derivative Works that You distribute must
+ include a readable copy of the attribution notices contained
+ within such NOTICE file, excluding those notices that do not
+ pertain to any part of the Derivative Works, in at least one
+ of the following places: within a NOTICE text file distributed
+ as part of the Derivative Works; within the Source form or
+ documentation, if provided along with the Derivative Works; or,
+ within a display generated by the Derivative Works, if and
+ wherever such third-party notices normally appear. The contents
+ of the NOTICE file are for informational purposes only and
+ do not modify the License. You may add Your own attribution
+ notices within Derivative Works that You distribute, alongside
+ or as an addendum to the NOTICE text from the Work, provided
+ that such additional attribution notices cannot be construed
+ as modifying the License.
+
+ You may add Your own copyright statement to Your modifications and
+ may provide additional or different license terms and conditions
+ for use, reproduction, or distribution of Your modifications, or
+ for any such Derivative Works as a whole, provided Your use,
+ reproduction, and distribution of the Work otherwise complies with
+ the conditions stated in this License.
+
+ 5. Submission of Contributions. Unless You explicitly state otherwise,
+ any Contribution intentionally submitted for inclusion in the Work
+ by You to the Licensor shall be under the terms and conditions of
+ this License, without any additional terms or conditions.
+ Notwithstanding the above, nothing herein shall supersede or modify
+ the terms of any separate license agreement you may have executed
+ with Licensor regarding such Contributions.
+
+ 6. Trademarks. This License does not grant permission to use the trade
+ names, trademarks, service marks, or product names of the Licensor,
+ except as required for reasonable and customary use in describing the
+ origin of the Work and reproducing the content of the NOTICE file.
+
+ 7. Disclaimer of Warranty. Unless required by applicable law or
+ agreed to in writing, Licensor provides the Work (and each
+ Contributor provides its Contributions) on an "AS IS" BASIS,
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+ of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
+ PARTICULAR PURPOSE. You are solely responsible for determining the
+ appropriateness of using or redistributing the Work and assume any
+ risks associated with Your exercise of permissions under this License.
+
+ 8. Limitation of Liability. In no event and under no legal theory,
+ whether in tort (including negligence), contract, or otherwise,
+ unless required by applicable law (such as deliberate and grossly
+ negligent acts) or agreed to in writing, shall any Contributor be
+ liable to You for damages, including any direct, indirect, special,
+ incidental, or consequential damages of any character arising as a
+ result of this License or out of the use or inability to use the
+ Work (including but not limited to damages for loss of goodwill,
+ work stoppage, computer failure or malfunction, or any and all
+ other commercial damages or losses), even if such Contributor
+ has been advised of the possibility of such damages.
+
+ 9. Accepting Warranty or Additional Liability. While redistributing
+ the Work or Derivative Works thereof, You may choose to offer,
+ and charge a fee for, acceptance of support, warranty, indemnity,
+ or other liability obligations and/or rights consistent with this
+ License. However, in accepting such obligations, You may act only
+ on Your own behalf and on Your sole responsibility, not on behalf
+ of any other Contributor, and only if You agree to indemnify,
+ defend, and hold each Contributor harmless for any liability
+ incurred by, or claims asserted against, such Contributor by reason
+ of your accepting any such warranty or additional liability.
+
+ END OF TERMS AND CONDITIONS
+
diff --git a/libcorkscrew/arch-arm/backtrace-arm.c b/libcorkscrew/arch-arm/backtrace-arm.c
new file mode 100644
index 0000000..f2db642
--- /dev/null
+++ b/libcorkscrew/arch-arm/backtrace-arm.c
@@ -0,0 +1,516 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Backtracing functions for ARM.
+ *
+ * This implementation uses the exception unwinding tables provided by
+ * the compiler to unwind call frames. Refer to the ARM Exception Handling ABI
+ * documentation (EHABI) for more details about what's going on here.
+ *
+ * An ELF binary may contain an EXIDX section that provides an index to
+ * the exception handling table of each function, sorted by program
+ * counter address.
+ *
+ * When the executable is statically linked, the EXIDX section can be
+ * accessed by querying the values of the __exidx_start and __exidx_end
+ * symbols. That said, this library is currently only compiled as
+ * a dynamic library, so we will not trouble ourselves with statically
+ * linked executables any further.
+ *
+ * When the Bionic dynamic linker is used, it exports a function called
+ * dl_unwind_find_exidx that obtains the EXIDX section for a given
+ * absolute program counter address.
+ *
+ * This implementation also supports unwinding other processes via ptrace().
+ * In that case, the EXIDX section is found by reading the ELF section table
+ * structures using ptrace().
+ *
+ * Because the tables are used for exception handling, it can happen that
+ * a given function will not have an exception handling table. In particular,
+ * exceptions are assumes to only ever be thrown at call sites. Therefore,
+ * by definition leaf functions will not have exception handling tables.
+ * This may make unwinding impossible in some cases although we can still get
+ * some idea of the call stack by examining the PC and LR registers.
+ *
+ * As we are only interested in backtrace information, we do not need
+ * to perform all of the work of unwinding such as restoring register
+ * state and running cleanup functions. Unwinding is performed virtually on
+ * an abstract machine context consisting of just the ARM core registers.
+ * Furthermore, we do not run generic "personality functions" because
+ * we may not be in a position to execute arbitrary code, especially if
+ * we are running in a signal handler or using ptrace()!
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "../backtrace-arch.h"
+#include "../backtrace-helper.h"
+#include "../ptrace-arch.h"
+#include <corkscrew/ptrace.h>
+
+#include <stdlib.h>
+#include <signal.h>
+#include <stdbool.h>
+#include <limits.h>
+#include <errno.h>
+#include <sys/ptrace.h>
+#include <sys/exec_elf.h>
+#include <cutils/log.h>
+
+/* Machine context at the time a signal was raised. */
+typedef struct ucontext {
+ uint32_t uc_flags;
+ struct ucontext* uc_link;
+ stack_t uc_stack;
+ struct sigcontext {
+ uint32_t trap_no;
+ uint32_t error_code;
+ uint32_t oldmask;
+ uint32_t gregs[16];
+ uint32_t arm_cpsr;
+ uint32_t fault_address;
+ } uc_mcontext;
+ uint32_t uc_sigmask;
+} ucontext_t;
+
+/* Unwind state. */
+typedef struct {
+ uint32_t gregs[16];
+} unwind_state_t;
+
+static const int R_SP = 13;
+static const int R_LR = 14;
+static const int R_PC = 15;
+
+/* Special EXIDX value that indicates that a frame cannot be unwound. */
+static const uint32_t EXIDX_CANTUNWIND = 1;
+
+/* The function exported by the Bionic linker to find the EXIDX
+ * table for a given program counter address. */
+extern uintptr_t dl_unwind_find_exidx(uintptr_t pc, size_t* out_exidx_size);
+
+/* Transforms a 31-bit place-relative offset to an absolute address.
+ * We assume the most significant bit is clear. */
+static uintptr_t prel_to_absolute(uintptr_t place, uint32_t prel_offset) {
+ return place + (((int32_t)(prel_offset << 1)) >> 1);
+}
+
+static uintptr_t get_exception_handler(
+ const ptrace_context_t* context, pid_t tid, uintptr_t pc) {
+ uintptr_t exidx_start;
+ size_t exidx_size;
+ if (tid < 0) {
+ exidx_start = dl_unwind_find_exidx(pc, &exidx_size);
+ } else {
+ const map_info_t* mi = find_map_info(context->map_info_list, pc);
+ if (mi && mi->data) {
+ const map_info_data_t* data = (const map_info_data_t*)mi->data;
+ exidx_start = data->exidx_start;
+ exidx_size = data->exidx_size;
+ } else {
+ exidx_start = 0;
+ exidx_size = 0;
+ }
+ }
+
+ // The PC points to the instruction following the branch.
+ // We want to find the exception handler entry that corresponds to the branch itself,
+ // so we offset the PC backwards into the previous instruction.
+ // ARM instructions are 4 bytes, Thumb are 2, so we just subtract two so we either
+ // end up in the middle (ARM) or at the beginning of the instruction (Thumb).
+ if (pc >= 2) {
+ pc -= 2;
+ }
+
+ uint32_t handler = 0;
+ if (exidx_start) {
+ uint32_t low = 0;
+ uint32_t high = exidx_size;
+ while (low < high) {
+ uint32_t index = (low + high) / 2;
+ uintptr_t entry = exidx_start + index * 8;
+ uint32_t entry_prel_pc;
+ if (!try_get_word(tid, entry, &entry_prel_pc)) {
+ break;
+ }
+ uintptr_t entry_pc = prel_to_absolute(entry, entry_prel_pc);
+ if (pc < entry_pc) {
+ high = index;
+ continue;
+ }
+ if (index + 1 < exidx_size) {
+ uintptr_t next_entry = entry + 8;
+ uint32_t next_entry_prel_pc;
+ if (!try_get_word(tid, next_entry, &next_entry_prel_pc)) {
+ break;
+ }
+ uintptr_t next_entry_pc = prel_to_absolute(next_entry, next_entry_prel_pc);
+ if (pc >= next_entry_pc) {
+ low = index + 1;
+ continue;
+ }
+ }
+
+ uintptr_t entry_handler_ptr = entry + 4;
+ uint32_t entry_handler;
+ if (!try_get_word(tid, entry_handler_ptr, &entry_handler)) {
+ break;
+ }
+ if (entry_handler & (1L << 31)) {
+ handler = entry_handler_ptr; // in-place handler data
+ } else if (entry_handler != EXIDX_CANTUNWIND) {
+ handler = prel_to_absolute(entry_handler_ptr, entry_handler);
+ }
+ break;
+ }
+ }
+ LOGV("get handler: pc=0x%08x, exidx_start=0x%08x, exidx_size=%d, handler=0x%08x",
+ pc, exidx_start, exidx_size, handler);
+ return handler;
+}
+
+typedef struct {
+ uintptr_t ptr;
+ uint32_t word;
+} byte_stream_t;
+
+static bool try_next_byte(pid_t tid, byte_stream_t* stream, uint8_t* out_value) {
+ uint8_t result;
+ switch (stream->ptr & 3) {
+ case 0:
+ if (!try_get_word(tid, stream->ptr, &stream->word)) {
+ *out_value = 0;
+ return false;
+ }
+ *out_value = stream->word >> 24;
+ break;
+
+ case 1:
+ *out_value = stream->word >> 16;
+ break;
+
+ case 2:
+ *out_value = stream->word >> 8;
+ break;
+
+ default:
+ *out_value = stream->word;
+ break;
+ }
+
+ LOGV("next_byte: ptr=0x%08x, value=0x%02x", stream->ptr, *out_value);
+ stream->ptr += 1;
+ return true;
+}
+
+static void set_reg(unwind_state_t* state, uint32_t reg, uint32_t value) {
+ LOGV("set_reg: reg=%d, value=0x%08x", reg, value);
+ state->gregs[reg] = value;
+}
+
+static bool try_pop_registers(pid_t tid, unwind_state_t* state, uint32_t mask) {
+ uint32_t sp = state->gregs[R_SP];
+ bool sp_updated = false;
+ for (int i = 0; i < 16; i++) {
+ if (mask & (1 << i)) {
+ uint32_t value;
+ if (!try_get_word(tid, sp, &value)) {
+ return false;
+ }
+ if (i == R_SP) {
+ sp_updated = true;
+ }
+ set_reg(state, i, value);
+ sp += 4;
+ }
+ }
+ if (!sp_updated) {
+ set_reg(state, R_SP, sp);
+ }
+ return true;
+}
+
+/* Executes a built-in personality routine as defined in the EHABI.
+ * Returns true if unwinding should continue.
+ *
+ * The data for the built-in personality routines consists of a sequence
+ * of unwinding instructions, followed by a sequence of scope descriptors,
+ * each of which has a length and offset encoded using 16-bit or 32-bit
+ * values.
+ *
+ * We only care about the unwinding instructions. They specify the
+ * operations of an abstract machine whose purpose is to transform the
+ * virtual register state (including the stack pointer) such that
+ * the call frame is unwound and the PC register points to the call site.
+ */
+static bool execute_personality_routine(pid_t tid, unwind_state_t* state,
+ byte_stream_t* stream, int pr_index) {
+ size_t size;
+ switch (pr_index) {
+ case 0: // Personality routine #0, short frame, descriptors have 16-bit scope.
+ size = 3;
+ break;
+ case 1: // Personality routine #1, long frame, descriptors have 16-bit scope.
+ case 2: { // Personality routine #2, long frame, descriptors have 32-bit scope.
+ uint8_t size_byte;
+ if (!try_next_byte(tid, stream, &size_byte)) {
+ return false;
+ }
+ size = (uint32_t)size_byte * sizeof(uint32_t) + 2;
+ break;
+ }
+ default: // Unknown personality routine. Stop here.
+ return false;
+ }
+
+ bool pc_was_set = false;
+ while (size--) {
+ uint8_t op;
+ if (!try_next_byte(tid, stream, &op)) {
+ return false;
+ }
+ if ((op & 0xc0) == 0x00) {
+ // "vsp = vsp + (xxxxxx << 2) + 4"
+ set_reg(state, R_SP, state->gregs[R_SP] + ((op & 0x3f) << 2) + 4);
+ } else if ((op & 0xc0) == 0x40) {
+ // "vsp = vsp - (xxxxxx << 2) - 4"
+ set_reg(state, R_SP, state->gregs[R_SP] - ((op & 0x3f) << 2) - 4);
+ } else if ((op & 0xf0) == 0x80) {
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ uint32_t mask = (((uint32_t)op & 0x0f) << 12) | ((uint32_t)op2 << 4);
+ if (mask) {
+ // "Pop up to 12 integer registers under masks {r15-r12}, {r11-r4}"
+ if (!try_pop_registers(tid, state, mask)) {
+ return false;
+ }
+ if (mask & (1 << R_PC)) {
+ pc_was_set = true;
+ }
+ } else {
+ // "Refuse to unwind"
+ return false;
+ }
+ } else if ((op & 0xf0) == 0x90) {
+ if (op != 0x9d && op != 0x9f) {
+ // "Set vsp = r[nnnn]"
+ set_reg(state, R_SP, state->gregs[op & 0x0f]);
+ } else {
+ // "Reserved as prefix for ARM register to register moves"
+ // "Reserved as prefix for Intel Wireless MMX register to register moves"
+ return false;
+ }
+ } else if ((op & 0xf8) == 0xa0) {
+ // "Pop r4-r[4+nnn]"
+ uint32_t mask = (0x0ff0 >> (7 - (op & 0x07))) & 0x0ff0;
+ if (!try_pop_registers(tid, state, mask)) {
+ return false;
+ }
+ } else if ((op & 0xf8) == 0xa8) {
+ // "Pop r4-r[4+nnn], r14"
+ uint32_t mask = ((0x0ff0 >> (7 - (op & 0x07))) & 0x0ff0) | 0x4000;
+ if (!try_pop_registers(tid, state, mask)) {
+ return false;
+ }
+ } else if (op == 0xb0) {
+ // "Finish"
+ break;
+ } else if (op == 0xb1) {
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ if (op2 != 0x00 && (op2 & 0xf0) == 0x00) {
+ // "Pop integer registers under mask {r3, r2, r1, r0}"
+ if (!try_pop_registers(tid, state, op2)) {
+ return false;
+ }
+ } else {
+ // "Spare"
+ return false;
+ }
+ } else if (op == 0xb2) {
+ // "vsp = vsp + 0x204 + (uleb128 << 2)"
+ uint32_t value = 0;
+ uint32_t shift = 0;
+ uint8_t op2;
+ do {
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ value |= (op2 & 0x7f) << shift;
+ shift += 7;
+ } while (op2 & 0x80);
+ set_reg(state, R_SP, state->gregs[R_SP] + (value << 2) + 0x204);
+ } else if (op == 0xb3) {
+ // "Pop VFP double-precision registers D[ssss]-D[ssss+cccc] saved (as if) by FSTMFDX"
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 12);
+ } else if ((op & 0xf8) == 0xb8) {
+ // "Pop VFP double-precision registers D[8]-D[8+nnn] saved (as if) by FSTMFDX"
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op & 0x07) * 8 + 12);
+ } else if ((op & 0xf8) == 0xc0) {
+ // "Intel Wireless MMX pop wR[10]-wR[10+nnn]"
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op & 0x07) * 8 + 8);
+ } else if (op == 0xc6) {
+ // "Intel Wireless MMX pop wR[ssss]-wR[ssss+cccc]"
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 8);
+ } else if (op == 0xc7) {
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ if (op2 != 0x00 && (op2 & 0xf0) == 0x00) {
+ // "Intel Wireless MMX pop wCGR registers under mask {wCGR3,2,1,0}"
+ set_reg(state, R_SP, state->gregs[R_SP] + __builtin_popcount(op2) * 4);
+ } else {
+ // "Spare"
+ return false;
+ }
+ } else if (op == 0xc8) {
+ // "Pop VFP double precision registers D[16+ssss]-D[16+ssss+cccc]
+ // saved (as if) by FSTMFD"
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 8);
+ } else if (op == 0xc9) {
+ // "Pop VFP double precision registers D[ssss]-D[ssss+cccc] saved (as if) by FSTMFDD"
+ uint8_t op2;
+ if (!(size--) || !try_next_byte(tid, stream, &op2)) {
+ return false;
+ }
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op2 & 0x0f) * 8 + 8);
+ } else if ((op == 0xf8) == 0xd0) {
+ // "Pop VFP double-precision registers D[8]-D[8+nnn] saved (as if) by FSTMFDD"
+ set_reg(state, R_SP, state->gregs[R_SP] + (uint32_t)(op & 0x07) * 8 + 8);
+ } else {
+ // "Spare"
+ return false;
+ }
+ }
+ if (!pc_was_set) {
+ set_reg(state, R_PC, state->gregs[R_LR]);
+ }
+ return true;
+}
+
+static ssize_t unwind_backtrace_common(pid_t tid, const ptrace_context_t* context,
+ unwind_state_t* state, backtrace_frame_t* backtrace,
+ size_t ignore_depth, size_t max_depth) {
+ size_t ignored_frames = 0;
+ size_t returned_frames = 0;
+
+ uintptr_t handler = get_exception_handler(context, tid, state->gregs[R_PC]);
+ if (!handler) {
+ // If there is no handler for the PC, the program may have branched to
+ // an invalid address. Check whether we have a handler for the LR
+ // where we came from and use that instead.
+ backtrace_frame_t* frame = add_backtrace_entry(state->gregs[R_PC], backtrace,
+ ignore_depth, max_depth, &ignored_frames, &returned_frames);
+ if (frame) {
+ frame->stack_top = state->gregs[R_SP];
+ }
+
+ handler = get_exception_handler(context, tid, state->gregs[R_LR]);
+ if (!handler) {
+ // We don't have a handler here either. Unwinding will not be possible.
+ // Return the PC and LR (if it looks sane) and call it good.
+ if (state->gregs[R_LR] && state->gregs[R_LR] != state->gregs[R_PC]) {
+ // Don't return the SP for this second frame because we don't
+ // know how big the first one is so we don't know where this
+ // one starts.
+ frame = add_backtrace_entry(state->gregs[R_LR], backtrace,
+ ignore_depth, max_depth, &ignored_frames, &returned_frames);
+ }
+ return returned_frames;
+ }
+
+ // Ok, continue from the LR.
+ set_reg(state, R_PC, state->gregs[R_LR]);
+ }
+
+ while (handler && returned_frames < max_depth) {
+ backtrace_frame_t* frame = add_backtrace_entry(state->gregs[R_PC], backtrace,
+ ignore_depth, max_depth, &ignored_frames, &returned_frames);
+ if (frame) {
+ frame->stack_top = state->gregs[R_SP];
+ }
+
+ byte_stream_t stream;
+ stream.ptr = handler;
+ uint8_t pr;
+ if (!try_next_byte(tid, &stream, &pr)) {
+ break;
+ }
+ if ((pr & 0xf0) != 0x80) {
+ // The first word is a place-relative pointer to a generic personality
+ // routine function. We don't support invoking such functions, so stop here.
+ break;
+ }
+
+ // The first byte indicates the personality routine to execute.
+ // Following bytes provide instructions to the personality routine.
+ if (!execute_personality_routine(tid, state, &stream, pr & 0x0f)) {
+ break;
+ }
+ if (frame && state->gregs[R_SP] > frame->stack_top) {
+ frame->stack_size = state->gregs[R_SP] - frame->stack_top;
+ }
+
+ handler = get_exception_handler(context, tid, state->gregs[R_PC]);
+ }
+ return returned_frames;
+}
+
+ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext,
+ backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+ const ucontext_t* uc = (const ucontext_t*)sigcontext;
+
+ unwind_state_t state;
+ for (int i = 0; i < 16; i++) {
+ state.gregs[i] = uc->uc_mcontext.gregs[i];
+ }
+
+ return unwind_backtrace_common(-1, NULL, &state, backtrace, ignore_depth, max_depth);
+}
+
+ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context,
+ backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+ struct pt_regs regs;
+ if (ptrace(PTRACE_GETREGS, tid, 0, &regs)) {
+ return -1;
+ }
+
+ unwind_state_t state;
+ for (int i = 0; i < 16; i++) {
+ state.gregs[i] = regs.uregs[i];
+ }
+
+ return unwind_backtrace_common(tid, context, &state, backtrace, ignore_depth, max_depth);
+}
diff --git a/libcorkscrew/arch-arm/ptrace-arm.c b/libcorkscrew/arch-arm/ptrace-arm.c
new file mode 100644
index 0000000..fd15505
--- /dev/null
+++ b/libcorkscrew/arch-arm/ptrace-arm.c
@@ -0,0 +1,65 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "../ptrace-arch.h"
+
+#include <sys/exec_elf.h>
+#include <cutils/log.h>
+
+#ifndef PT_ARM_EXIDX
+#define PT_ARM_EXIDX 0x70000001
+#endif
+
+static void load_exidx_header(pid_t pid, map_info_t* mi,
+ uintptr_t* out_exidx_start, size_t* out_exidx_size) {
+ uint32_t elf_phoff;
+ uint32_t elf_phnum;
+ if (try_get_word(pid, mi->start + offsetof(Elf32_Ehdr, e_phoff), &elf_phoff)
+ && try_get_word(pid, mi->start + offsetof(Elf32_Ehdr, e_phnum), &elf_phnum)) {
+ for (uint32_t i = 0; i < elf_phnum; i++) {
+ uintptr_t elf_phdr = mi->start + elf_phoff + i * sizeof(Elf32_Phdr);
+ uint32_t elf_phdr_type;
+ if (!try_get_word(pid, elf_phdr + offsetof(Elf32_Phdr, p_type), &elf_phdr_type)) {
+ break;
+ }
+ if (elf_phdr_type == PT_ARM_EXIDX) {
+ uint32_t elf_phdr_offset;
+ uint32_t elf_phdr_filesz;
+ if (!try_get_word(pid, elf_phdr + offsetof(Elf32_Phdr, p_offset),
+ &elf_phdr_offset)
+ || !try_get_word(pid, elf_phdr + offsetof(Elf32_Phdr, p_filesz),
+ &elf_phdr_filesz)) {
+ break;
+ }
+ *out_exidx_start = mi->start + elf_phdr_offset;
+ *out_exidx_size = elf_phdr_filesz;
+ return;
+ }
+ }
+ }
+ *out_exidx_start = 0;
+ *out_exidx_size = 0;
+}
+
+void load_ptrace_map_info_data_arch(pid_t pid, map_info_t* mi, map_info_data_t* data) {
+ load_exidx_header(pid, mi, &data->exidx_start, &data->exidx_size);
+}
+
+void free_ptrace_map_info_data_arch(map_info_t* mi, map_info_data_t* data) {
+}
diff --git a/libcorkscrew/backtrace-arch.h b/libcorkscrew/backtrace-arch.h
new file mode 100644
index 0000000..80bca2b
--- /dev/null
+++ b/libcorkscrew/backtrace-arch.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Architecture dependent functions. */
+
+#ifndef _CORKSCREW_BACKTRACE_ARCH_H
+#define _CORKSCREW_BACKTRACE_ARCH_H
+
+#include "ptrace-arch.h"
+#include <corkscrew/backtrace.h>
+
+#include <signal.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+ssize_t unwind_backtrace_signal_arch(siginfo_t* siginfo, void* sigcontext,
+ backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth);
+
+ssize_t unwind_backtrace_ptrace_arch(pid_t tid, const ptrace_context_t* context,
+ backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_BACKTRACE_ARCH_H
diff --git a/libcorkscrew/backtrace-helper.c b/libcorkscrew/backtrace-helper.c
new file mode 100644
index 0000000..bf9d3f3
--- /dev/null
+++ b/libcorkscrew/backtrace-helper.c
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "backtrace-helper.h"
+
+#include <cutils/log.h>
+
+backtrace_frame_t* add_backtrace_entry(uintptr_t pc, backtrace_frame_t* backtrace,
+ size_t ignore_depth, size_t max_depth,
+ size_t* ignored_frames, size_t* returned_frames) {
+ if (*ignored_frames < ignore_depth) {
+ *ignored_frames += 1;
+ return NULL;
+ }
+ if (*returned_frames >= max_depth) {
+ return NULL;
+ }
+ backtrace_frame_t* frame = &backtrace[*returned_frames];
+ frame->absolute_pc = pc;
+ frame->stack_top = 0;
+ frame->stack_size = 0;
+ *returned_frames += 1;
+ return frame;
+}
diff --git a/libcorkscrew/backtrace-helper.h b/libcorkscrew/backtrace-helper.h
new file mode 100644
index 0000000..4d8a874
--- /dev/null
+++ b/libcorkscrew/backtrace-helper.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Backtrace helper functions. */
+
+#ifndef _CORKSCREW_BACKTRACE_HELPER_H
+#define _CORKSCREW_BACKTRACE_HELPER_H
+
+#include <corkscrew/backtrace.h>
+#include <sys/types.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Add a program counter to a backtrace if it will fit.
+ * Returns the newly added frame, or NULL if none.
+ */
+backtrace_frame_t* add_backtrace_entry(uintptr_t pc,
+ backtrace_frame_t* backtrace,
+ size_t ignore_depth, size_t max_depth,
+ size_t* ignored_frames, size_t* returned_frames);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_BACKTRACE_HELPER_H
diff --git a/libcorkscrew/backtrace.c b/libcorkscrew/backtrace.c
new file mode 100644
index 0000000..b03c43f
--- /dev/null
+++ b/libcorkscrew/backtrace.c
@@ -0,0 +1,205 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "backtrace-arch.h"
+#include "backtrace-helper.h"
+#include "ptrace-arch.h"
+#include <corkscrew/map_info.h>
+#include <corkscrew/symbol_table.h>
+#include <corkscrew/ptrace.h>
+#include <corkscrew/demangle.h>
+
+#include <unistd.h>
+#include <signal.h>
+#include <pthread.h>
+#include <unwind.h>
+#include <sys/exec_elf.h>
+#include <cutils/log.h>
+
+#if HAVE_DLADDR
+#include <dlfcn.h>
+#endif
+
+typedef struct {
+ backtrace_frame_t* backtrace;
+ size_t ignore_depth;
+ size_t max_depth;
+ size_t ignored_frames;
+ size_t returned_frames;
+} backtrace_state_t;
+
+static _Unwind_Reason_Code unwind_backtrace_callback(struct _Unwind_Context* context, void* arg) {
+ backtrace_state_t* state = (backtrace_state_t*)arg;
+ uintptr_t pc = _Unwind_GetIP(context);
+ if (pc) {
+ // TODO: Get information about the stack layout from the _Unwind_Context.
+ // This will require a new architecture-specific function to query
+ // the appropriate registers. Current callers of unwind_backtrace
+ // don't need this information, so we won't bother collecting it just yet.
+ add_backtrace_entry(pc, state->backtrace,
+ state->ignore_depth, state->max_depth,
+ &state->ignored_frames, &state->returned_frames);
+ }
+ return state->returned_frames < state->max_depth ? _URC_NO_REASON : _URC_END_OF_STACK;
+}
+
+ssize_t unwind_backtrace(backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+ backtrace_state_t state;
+ state.backtrace = backtrace;
+ state.ignore_depth = ignore_depth;
+ state.max_depth = max_depth;
+ state.ignored_frames = 0;
+ state.returned_frames = 0;
+
+ _Unwind_Reason_Code rc =_Unwind_Backtrace(unwind_backtrace_callback, &state);
+ if (state.returned_frames) {
+ return state.returned_frames;
+ }
+ return rc == _URC_END_OF_STACK ? 0 : -1;
+}
+
+#ifdef CORKSCREW_HAVE_ARCH
+static pthread_mutex_t g_unwind_signal_mutex = PTHREAD_MUTEX_INITIALIZER;
+static volatile struct {
+ backtrace_frame_t* backtrace;
+ size_t ignore_depth;
+ size_t max_depth;
+ size_t returned_frames;
+ bool done;
+} g_unwind_signal_state;
+
+static void unwind_backtrace_thread_signal_handler(int n, siginfo_t* siginfo, void* sigcontext) {
+ backtrace_frame_t* backtrace = g_unwind_signal_state.backtrace;
+ if (backtrace) {
+ g_unwind_signal_state.backtrace = NULL;
+ g_unwind_signal_state.returned_frames = unwind_backtrace_signal_arch(
+ siginfo, sigcontext, backtrace,
+ g_unwind_signal_state.ignore_depth,
+ g_unwind_signal_state.max_depth);
+ g_unwind_signal_state.done = true;
+ }
+}
+#endif
+
+ssize_t unwind_backtrace_thread(pid_t tid, backtrace_frame_t* backtrace,
+ size_t ignore_depth, size_t max_depth) {
+#ifdef CORKSCREW_HAVE_ARCH
+ struct sigaction act;
+ struct sigaction oact;
+ memset(&act, 0, sizeof(act));
+ act.sa_sigaction = unwind_backtrace_thread_signal_handler;
+ act.sa_flags = SA_RESTART | SA_SIGINFO;
+ sigemptyset(&act.sa_mask);
+
+ pthread_mutex_lock(&g_unwind_signal_mutex);
+
+ g_unwind_signal_state.backtrace = backtrace;
+ g_unwind_signal_state.ignore_depth = ignore_depth;
+ g_unwind_signal_state.max_depth = max_depth;
+ g_unwind_signal_state.returned_frames = 0;
+ g_unwind_signal_state.done = false;
+
+ ssize_t frames = -1;
+ if (!sigaction(SIGURG, &act, &oact)) {
+ if (!kill(tid, SIGURG)) {
+ while (!g_unwind_signal_state.done) {
+ usleep(1000);
+ }
+ frames = g_unwind_signal_state.returned_frames;
+ }
+ sigaction(SIGURG, &oact, NULL);
+ }
+
+ g_unwind_signal_state.backtrace = NULL;
+
+ pthread_mutex_unlock(&g_unwind_signal_mutex);
+ return frames;
+#else
+ return -1;
+#endif
+}
+
+ssize_t unwind_backtrace_ptrace(pid_t tid, const ptrace_context_t* context,
+ backtrace_frame_t* backtrace, size_t ignore_depth, size_t max_depth) {
+#ifdef CORKSCREW_HAVE_ARCH
+ return unwind_backtrace_ptrace_arch(tid, context, backtrace, ignore_depth, max_depth);
+#else
+ return -1;
+#endif
+}
+
+static void init_backtrace_symbol(backtrace_symbol_t* symbol, uintptr_t pc) {
+ symbol->relative_pc = pc;
+ symbol->map_info = NULL;
+ symbol->name = NULL;
+ symbol->demangled_name = NULL;
+}
+
+void get_backtrace_symbols(const backtrace_frame_t* backtrace, size_t frames,
+ backtrace_symbol_t* backtrace_symbols) {
+ const map_info_t* milist = my_map_info_list();
+ for (size_t i = 0; i < frames; i++) {
+ const backtrace_frame_t* frame = &backtrace[i];
+ backtrace_symbol_t* symbol = &backtrace_symbols[i];
+ init_backtrace_symbol(symbol, frame->absolute_pc);
+
+ const map_info_t* mi = find_map_info(milist, frame->absolute_pc);
+ if (mi) {
+ symbol->relative_pc = frame->absolute_pc - mi->start;
+ symbol->map_info = mi;
+#if HAVE_DLADDR
+ Dl_info info;
+ if (dladdr((const void*)frame->absolute_pc, &info) && info.dli_sname) {
+ symbol->name = info.dli_sname;
+ symbol->demangled_name = demangle_symbol_name(symbol->name);
+ }
+#endif
+ }
+ }
+}
+
+void get_backtrace_symbols_ptrace(const ptrace_context_t* context,
+ const backtrace_frame_t* backtrace, size_t frames,
+ backtrace_symbol_t* backtrace_symbols) {
+ for (size_t i = 0; i < frames; i++) {
+ const backtrace_frame_t* frame = &backtrace[i];
+ backtrace_symbol_t* symbol = &backtrace_symbols[i];
+ init_backtrace_symbol(symbol, frame->absolute_pc);
+
+ const map_info_t* mi;
+ const symbol_t* s;
+ find_symbol_ptrace(context, frame->absolute_pc, &mi, &s);
+ if (mi) {
+ symbol->relative_pc = frame->absolute_pc - mi->start;
+ symbol->map_info = mi;
+ }
+ if (s) {
+ symbol->name = s->name;
+ symbol->demangled_name = demangle_symbol_name(symbol->name);
+ }
+ }
+}
+
+void free_backtrace_symbols(backtrace_symbol_t* backtrace_symbols, size_t frames) {
+ for (size_t i = 0; i < frames; i++) {
+ backtrace_symbol_t* symbol = &backtrace_symbols[i];
+ free(symbol->demangled_name);
+ init_backtrace_symbol(symbol, 0);
+ }
+}
diff --git a/libcorkscrew/demangle.c b/libcorkscrew/demangle.c
new file mode 100644
index 0000000..ecb2c98
--- /dev/null
+++ b/libcorkscrew/demangle.c
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include <corkscrew/demangle.h>
+
+#include <cutils/log.h>
+
+#ifdef CORKSCREW_HAVE_LIBIBERTY
+// Defined in libiberty.a
+extern char *cplus_demangle(const char *mangled, int options);
+#endif
+
+char* demangle_symbol_name(const char* name) {
+#ifdef CORKSCREW_HAVE_LIBIBERTY
+ return name ? cplus_demangle(name, 0) : NULL;
+#else
+ return NULL;
+#endif
+}
diff --git a/libcorkscrew/map_info.c b/libcorkscrew/map_info.c
new file mode 100644
index 0000000..60ed9b4
--- /dev/null
+++ b/libcorkscrew/map_info.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include <corkscrew/map_info.h>
+
+#include <ctype.h>
+#include <stdio.h>
+#include <string.h>
+#include <limits.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <cutils/log.h>
+
+// 6f000000-6f01e000 rwxp 00000000 00:0c 16389419 /system/lib/libcomposer.so\n
+// 012345678901234567890123456789012345678901234567890123456789
+// 0 1 2 3 4 5
+static map_info_t* parse_maps_line(const char* line)
+{
+ unsigned long int start;
+ unsigned long int end;
+ char permissions[5];
+ int name_pos;
+ if (sscanf(line, "%lx-%lx %4s %*x %*x:%*x %*d%n", &start, &end,
+ permissions, &name_pos) != 3) {
+ return NULL;
+ }
+
+ while (isspace(line[name_pos])) {
+ name_pos += 1;
+ }
+ const char* name = line + name_pos;
+ size_t name_len = strlen(name);
+ if (name_len && name[name_len - 1] == '\n') {
+ name_len -= 1;
+ }
+
+ map_info_t* mi = calloc(1, sizeof(map_info_t) + name_len + 1);
+ if (mi) {
+ mi->start = start;
+ mi->end = end;
+ mi->is_executable = strlen(permissions) == 4 && permissions[2] == 'x';
+ mi->data = NULL;
+ memcpy(mi->name, name, name_len);
+ mi->name[name_len] = '\0';
+ }
+ return mi;
+}
+
+map_info_t* load_map_info_list(pid_t tid) {
+ char path[PATH_MAX];
+ char line[1024];
+ FILE* fp;
+ map_info_t* milist = NULL;
+
+ snprintf(path, PATH_MAX, "/proc/%d/maps", tid);
+ fp = fopen(path, "r");
+ if (fp) {
+ while(fgets(line, sizeof(line), fp)) {
+ map_info_t* mi = parse_maps_line(line);
+ if (mi) {
+ mi->next = milist;
+ milist = mi;
+ }
+ }
+ fclose(fp);
+ }
+ return milist;
+}
+
+void free_map_info_list(map_info_t* milist) {
+ while (milist) {
+ map_info_t* next = milist->next;
+ free(milist);
+ milist = next;
+ }
+}
+
+const map_info_t* find_map_info(const map_info_t* milist, uintptr_t addr) {
+ const map_info_t* mi = milist;
+ while (mi && !(addr >= mi->start && addr < mi->end)) {
+ mi = mi->next;
+ }
+ return mi;
+}
+
+static pthread_once_t g_my_milist_once = PTHREAD_ONCE_INIT;
+static map_info_t* g_my_milist = NULL;
+
+static void init_my_milist_once() {
+ g_my_milist = load_map_info_list(getpid());
+}
+
+const map_info_t* my_map_info_list() {
+ pthread_once(&g_my_milist_once, init_my_milist_once);
+ return g_my_milist;
+}
diff --git a/libcorkscrew/ptrace-arch.h b/libcorkscrew/ptrace-arch.h
new file mode 100644
index 0000000..c02df52
--- /dev/null
+++ b/libcorkscrew/ptrace-arch.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Architecture dependent functions. */
+
+#ifndef _CORKSCREW_PTRACE_ARCH_H
+#define _CORKSCREW_PTRACE_ARCH_H
+
+#include <corkscrew/ptrace.h>
+#include <corkscrew/map_info.h>
+#include <corkscrew/symbol_table.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Custom extra data we stuff into map_info_t structures as part
+ * of our ptrace_context_t. */
+typedef struct {
+#ifdef __arm__
+ uintptr_t exidx_start;
+ size_t exidx_size;
+#endif
+ symbol_table_t* symbol_table;
+} map_info_data_t;
+
+void load_ptrace_map_info_data_arch(pid_t pid, map_info_t* mi, map_info_data_t* data);
+void free_ptrace_map_info_data_arch(map_info_t* mi, map_info_data_t* data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // _CORKSCREW_PTRACE_ARCH_H
diff --git a/libcorkscrew/ptrace.c b/libcorkscrew/ptrace.c
new file mode 100644
index 0000000..6ed77c4
--- /dev/null
+++ b/libcorkscrew/ptrace.c
@@ -0,0 +1,134 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include "ptrace-arch.h"
+#include <corkscrew/ptrace.h>
+
+#include <errno.h>
+#include <sys/ptrace.h>
+#include <cutils/log.h>
+
+static const uint32_t ELF_MAGIC = 0x464C457f; // "ELF\0177"
+
+#ifndef PAGE_SIZE
+#define PAGE_SIZE 4096
+#endif
+
+#ifndef PAGE_MASK
+#define PAGE_MASK (~(PAGE_SIZE - 1))
+#endif
+
+bool try_get_word(pid_t tid, uintptr_t ptr, uint32_t* out_value) {
+ if (ptr & 3) {
+ LOGV("try_get_word: invalid pointer 0x%08x", ptr);
+ *out_value = 0;
+ return false;
+ }
+ if (tid < 0) {
+#if 0 /*unreliable, unclear whether this is safe from a signal handler context*/
+ // Determine whether the pointer is likely to be valid before dereferencing it.
+ unsigned char vec[1];
+ while (mincore((void*)(ptr & PAGE_MASK), sizeof(uint32_t), vec)) {
+ if (errno != EAGAIN && errno != EINTR) {
+ LOGV("try_get_word: invalid pointer 0x%08x, mincore() errno=%d", ptr, errno);
+ *out_value = 0;
+ return false;
+ }
+ }
+#endif
+ *out_value = *(uint32_t*)ptr;
+ return true;
+ } else {
+ // ptrace() returns -1 and sets errno when the operation fails.
+ // To disambiguate -1 from a valid result, we clear errno beforehand.
+ errno = 0;
+ *out_value = ptrace(PTRACE_PEEKTEXT, tid, (void*)ptr, NULL);
+ if (*out_value == 0xffffffffL && errno) {
+ LOGV("try_get_word: invalid pointer 0x%08x, ptrace() errno=%d", ptr, errno);
+ *out_value = 0;
+ return false;
+ }
+ return true;
+ }
+}
+
+static void load_ptrace_map_info_data(pid_t pid, map_info_t* mi) {
+ if (mi->is_executable) {
+ uint32_t elf_magic;
+ if (try_get_word(pid, mi->start, &elf_magic) && elf_magic == ELF_MAGIC) {
+ map_info_data_t* data = (map_info_data_t*)calloc(1, sizeof(map_info_data_t));
+ if (data) {
+ mi->data = data;
+ if (mi->name[0]) {
+ data->symbol_table = load_symbol_table(mi->name);
+ }
+#ifdef CORKSCREW_HAVE_ARCH
+ load_ptrace_map_info_data_arch(pid, mi, data);
+#endif
+ }
+ }
+ }
+}
+
+ptrace_context_t* load_ptrace_context(pid_t pid) {
+ ptrace_context_t* context =
+ (ptrace_context_t*)calloc(1, sizeof(ptrace_context_t));
+ if (context) {
+ context->map_info_list = load_map_info_list(pid);
+ for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) {
+ load_ptrace_map_info_data(pid, mi);
+ }
+ }
+ return context;
+}
+
+static void free_ptrace_map_info_data(map_info_t* mi) {
+ map_info_data_t* data = (map_info_data_t*)mi->data;
+ if (data) {
+ if (data->symbol_table) {
+ free_symbol_table(data->symbol_table);
+ }
+#ifdef CORKSCREW_HAVE_ARCH
+ free_ptrace_map_info_data_arch(mi, data);
+#endif
+ free(data);
+ mi->data = NULL;
+ }
+}
+
+void free_ptrace_context(ptrace_context_t* context) {
+ for (map_info_t* mi = context->map_info_list; mi; mi = mi->next) {
+ free_ptrace_map_info_data(mi);
+ }
+ free_map_info_list(context->map_info_list);
+}
+
+void find_symbol_ptrace(const ptrace_context_t* context,
+ uintptr_t addr, const map_info_t** out_map_info, const symbol_t** out_symbol) {
+ const map_info_t* mi = find_map_info(context->map_info_list, addr);
+ const symbol_t* symbol = NULL;
+ if (mi) {
+ const map_info_data_t* data = (const map_info_data_t*)mi->data;
+ if (data && data->symbol_table) {
+ symbol = find_symbol(data->symbol_table, addr - mi->start);
+ }
+ }
+ *out_map_info = mi;
+ *out_symbol = symbol;
+}
diff --git a/libcorkscrew/symbol_table.c b/libcorkscrew/symbol_table.c
new file mode 100644
index 0000000..8257c77
--- /dev/null
+++ b/libcorkscrew/symbol_table.c
@@ -0,0 +1,204 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "Corkscrew"
+//#define LOG_NDEBUG 0
+
+#include <corkscrew/symbol_table.h>
+
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <sys/exec_elf.h>
+#include <cutils/log.h>
+
+// Compare function for qsort
+static int qcompar(const void *a, const void *b) {
+ const symbol_t* asym = (const symbol_t*)a;
+ const symbol_t* bsym = (const symbol_t*)b;
+ if (asym->start > bsym->start) return 1;
+ if (asym->start < bsym->start) return -1;
+ return 0;
+}
+
+// Compare function for bsearch
+static int bcompar(const void *key, const void *element) {
+ uintptr_t addr = *(const uintptr_t*)key;
+ const symbol_t* symbol = (const symbol_t*)element;
+ if (addr < symbol->start) return -1;
+ if (addr >= symbol->end) return 1;
+ return 0;
+}
+
+symbol_table_t* load_symbol_table(const char *filename) {
+ symbol_table_t* table = NULL;
+
+ int fd = open(filename, O_RDONLY);
+ if (fd < 0) {
+ goto out;
+ }
+
+ struct stat sb;
+ if (fstat(fd, &sb)) {
+ goto out_close;
+ }
+
+ size_t length = sb.st_size;
+ char* base = mmap(NULL, length, PROT_READ, MAP_PRIVATE, fd, 0);
+ if (base == MAP_FAILED) {
+ goto out_close;
+ }
+
+ // Parse the file header
+ Elf32_Ehdr *hdr = (Elf32_Ehdr*)base;
+ if (!IS_ELF(*hdr)) {
+ goto out_close;
+ }
+ Elf32_Shdr *shdr = (Elf32_Shdr*)(base + hdr->e_shoff);
+
+ // Search for the dynamic symbols section
+ int sym_idx = -1;
+ int dynsym_idx = -1;
+ for (Elf32_Half i = 0; i < hdr->e_shnum; i++) {
+ if (shdr[i].sh_type == SHT_SYMTAB) {
+ sym_idx = i;
+ }
+ if (shdr[i].sh_type == SHT_DYNSYM) {
+ dynsym_idx = i;
+ }
+ }
+ if (dynsym_idx == -1 && sym_idx == -1) {
+ goto out_unmap;
+ }
+
+ table = malloc(sizeof(symbol_table_t));
+ if(!table) {
+ goto out_unmap;
+ }
+ table->num_symbols = 0;
+
+ Elf32_Sym *dynsyms = NULL;
+ int dynnumsyms = 0;
+ char *dynstr = NULL;
+ if (dynsym_idx != -1) {
+ dynsyms = (Elf32_Sym*)(base + shdr[dynsym_idx].sh_offset);
+ dynnumsyms = shdr[dynsym_idx].sh_size / shdr[dynsym_idx].sh_entsize;
+ int dynstr_idx = shdr[dynsym_idx].sh_link;
+ dynstr = base + shdr[dynstr_idx].sh_offset;
+ }
+
+ Elf32_Sym *syms = NULL;
+ int numsyms = 0;
+ char *str = NULL;
+ if (sym_idx != -1) {
+ syms = (Elf32_Sym*)(base + shdr[sym_idx].sh_offset);
+ numsyms = shdr[sym_idx].sh_size / shdr[sym_idx].sh_entsize;
+ int str_idx = shdr[sym_idx].sh_link;
+ str = base + shdr[str_idx].sh_offset;
+ }
+
+ int dynsymbol_count = 0;
+ if (dynsym_idx != -1) {
+ // Iterate through the dynamic symbol table, and count how many symbols
+ // are actually defined
+ for (int i = 0; i < dynnumsyms; i++) {
+ if (dynsyms[i].st_shndx != SHN_UNDEF) {
+ dynsymbol_count++;
+ }
+ }
+ }
+
+ size_t symbol_count = 0;
+ if (sym_idx != -1) {
+ // Iterate through the symbol table, and count how many symbols
+ // are actually defined
+ for (int i = 0; i < numsyms; i++) {
+ if (syms[i].st_shndx != SHN_UNDEF
+ && str[syms[i].st_name]
+ && syms[i].st_value
+ && syms[i].st_size) {
+ symbol_count++;
+ }
+ }
+ }
+
+ // Now, create an entry in our symbol table structure for each symbol...
+ table->num_symbols += symbol_count + dynsymbol_count;
+ table->symbols = malloc(table->num_symbols * sizeof(symbol_t));
+ if (!table->symbols) {
+ free(table);
+ table = NULL;
+ goto out_unmap;
+ }
+
+ size_t symbol_index = 0;
+ if (dynsym_idx != -1) {
+ // ...and populate them
+ for (int i = 0; i < dynnumsyms; i++) {
+ if (dynsyms[i].st_shndx != SHN_UNDEF) {
+ table->symbols[symbol_index].name = strdup(dynstr + dynsyms[i].st_name);
+ table->symbols[symbol_index].start = dynsyms[i].st_value;
+ table->symbols[symbol_index].end = dynsyms[i].st_value + dynsyms[i].st_size;
+ symbol_index += 1;
+ }
+ }
+ }
+
+ if (sym_idx != -1) {
+ // ...and populate them
+ for (int i = 0; i < numsyms; i++) {
+ if (syms[i].st_shndx != SHN_UNDEF
+ && str[syms[i].st_name]
+ && syms[i].st_value
+ && syms[i].st_size) {
+ table->symbols[symbol_index].name = strdup(str + syms[i].st_name);
+ table->symbols[symbol_index].start = syms[i].st_value;
+ table->symbols[symbol_index].end = syms[i].st_value + syms[i].st_size;
+ symbol_index += 1;
+ }
+ }
+ }
+
+ // Sort the symbol table entries, so they can be bsearched later
+ qsort(table->symbols, table->num_symbols, sizeof(symbol_t), qcompar);
+
+out_unmap:
+ munmap(base, length);
+
+out_close:
+ close(fd);
+
+out:
+ return table;
+}
+
+void free_symbol_table(symbol_table_t* table) {
+ if (table) {
+ for (size_t i = 0; i < table->num_symbols; i++) {
+ free(table->symbols[i].name);
+ }
+ free(table->symbols);
+ free(table);
+ }
+}
+
+const symbol_t* find_symbol(const symbol_table_t* table, uintptr_t addr) {
+ if (!table) return NULL;
+ return (const symbol_t*)bsearch(&addr, table->symbols, table->num_symbols,
+ sizeof(symbol_t), bcompar);
+}
generated by cgit v1.1 at 2024-12-25 06:42:24 +0000