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src/util/u_debug_stack.c

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+/**************************************************************************
+ *
+ * Copyright 2009 VMware, Inc.
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+ * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
+ * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
+ * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+
+/**
+ * @file
+ * Stack backtracing.
+ *
+ * @author Jose Fonseca <[email protected]>
+ */
+
+#include "util/simple_mtx.h"
+#include "util/u_debug.h"
+#include "u_debug_symbol.h"
+#include "u_debug_stack.h"
+#include "util/detect.h"
+
+#if defined(HAVE_LIBUNWIND)
+
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <dlfcn.h>
+
+#include "util/u_thread.h"
+#include "util/hash_table.h"
+
+static struct hash_table* symbols_hash;
+static simple_mtx_t symbols_mutex = SIMPLE_MTX_INITIALIZER;
+
+/* TODO with some refactoring we might be able to re-use debug_symbol_name_cached()
+ * instead.. otoh if using libunwind I think u_debug_symbol could just be excluded
+ * from build?
+ */
+static const char *
+symbol_name_cached(unw_cursor_t *cursor, unw_proc_info_t *pip)
+{
+   void *addr = (void *)(uintptr_t)pip->start_ip;
+   char *name;
+
+   simple_mtx_lock(&symbols_mutex);
+   if(!symbols_hash)
+      symbols_hash = _mesa_pointer_hash_table_create(NULL);
+   struct hash_entry *entry = _mesa_hash_table_search(symbols_hash, addr);
+   if (!entry) {
+      char procname[256];
+      unw_word_t off;
+      int ret;
+
+      ret = unw_get_proc_name(cursor, procname, sizeof(procname), &off);
+      if (ret && ret != -UNW_ENOMEM) {
+         procname[0] = '?';
+         procname[1] = 0;
+      }
+
+      if (asprintf(&name, "%s%s", procname, ret == -UNW_ENOMEM ? "..." : "") == -1)
+         name = "??";
+      entry = _mesa_hash_table_insert(symbols_hash, addr, (void*)name);
+   }
+   simple_mtx_unlock(&symbols_mutex);
+
+   return entry->data;
+}
+
+void
+debug_backtrace_capture(struct debug_stack_frame *backtrace,
+                        unsigned start_frame,
+                        unsigned nr_frames)
+{
+   unw_cursor_t cursor;
+   unw_context_t context;
+   unw_proc_info_t pip;
+   unsigned i = 0;
+
+   pip.unwind_info = 0;
+
+   unw_getcontext(&context);
+   unw_init_local(&cursor, &context);
+
+   while ((start_frame > 0) && (unw_step(&cursor) > 0))
+      start_frame--;
+
+   while ((i < nr_frames) && (unw_step(&cursor) > 0)) {
+      unw_word_t ip;
+
+      unw_get_reg(&cursor, UNW_REG_IP, &ip);
+      unw_get_proc_info(&cursor, &pip);
+
+      backtrace[i].start_ip = pip.start_ip;
+      backtrace[i].off      = ip - pip.start_ip;
+      backtrace[i].procname = symbol_name_cached(&cursor, &pip);
+
+      i++;
+   }
+
+   while (i < nr_frames) {
+      backtrace[i].start_ip = 0;
+      i++;
+   }
+}
+
+static const void *
+frame_ip(const struct debug_stack_frame *frame)
+{
+   return (void *)(uintptr_t)(frame->start_ip + frame->off);
+}
+
+static const char *
+frame_info(const struct debug_stack_frame *frame, unsigned *offset)
+{
+   Dl_info dlinfo;
+   const void *addr = frame_ip(frame);
+
+
+   if (dladdr(addr, &dlinfo) && dlinfo.dli_fname &&
+           *dlinfo.dli_fname) {
+      *offset = (unsigned)((uintptr_t)addr - (uintptr_t)dlinfo.dli_fbase);
+      return dlinfo.dli_fname;
+   }
+
+   *offset = 0;
+   return "?";
+}
+
+void
+debug_backtrace_dump(const struct debug_stack_frame *backtrace,
+                     unsigned nr_frames)
+{
+   unsigned i, offset;
+   const char *filename;
+
+   for (i = 0; i < nr_frames; ++i) {
+      if (!backtrace[i].start_ip)
+         break;
+      filename = frame_info(&backtrace[i], &offset);
+      debug_printf("\t%s(+0x%x) (%s+0x%x) [%p]\n", filename, offset,
+            backtrace[i].procname, backtrace[i].off,
+            frame_ip(&backtrace[i]));
+   }
+}
+
+void
+debug_backtrace_print(FILE *f,
+                      const struct debug_stack_frame *backtrace,
+                      unsigned nr_frames)
+{
+   unsigned i, offset;
+   const char *filename;
+
+   for (i = 0; i < nr_frames; ++i) {
+      if (!backtrace[i].start_ip)
+         break;
+      filename = frame_info(&backtrace[i], &offset);
+      fprintf(f, "\t%s(+0x%x) (%s+0x%x) [%p]\n", filename, offset,
+            backtrace[i].procname, backtrace[i].off,
+            frame_ip(&backtrace[i]));
+   }
+}
+#elif DETECT_OS_ANDROID
+   /* Not implemented here; see u_debug_stack_android.cpp */
+#else /* ! HAVE_LIBUNWIND */
+
+#if DETECT_OS_WINDOWS
+#include <windows.h>
+#endif
+
+/**
+ * Capture stack backtrace.
+ *
+ * NOTE: The implementation of this function is quite big, but it is important
+ * not to break it down in smaller functions to avoid adding new frames to the
+ * calling stack.
+ */
+void
+debug_backtrace_capture(struct debug_stack_frame *backtrace,
+                        unsigned start_frame,
+                        unsigned nr_frames)
+{
+   unsigned i = 0;
+
+   if (!nr_frames) {
+      return;
+   }
+
+   /*
+    * On Windows try obtaining the stack backtrace via CaptureStackBackTrace.
+    *
+    * It works reliably both for x86 for x86_64.
+    */
+#if DETECT_OS_WINDOWS
+   {
+      typedef USHORT (WINAPI *PFNCAPTURESTACKBACKTRACE)(ULONG, ULONG,
+                                                        PVOID *, PULONG);
+      static PFNCAPTURESTACKBACKTRACE pfnCaptureStackBackTrace = NULL;
+
+      if (!pfnCaptureStackBackTrace) {
+         static HMODULE hModule = NULL;
+         if (!hModule) {
+            hModule = LoadLibraryA("kernel32");
+            assert(hModule);
+         }
+         if (hModule) {
+            pfnCaptureStackBackTrace =
+               (PFNCAPTURESTACKBACKTRACE)GetProcAddress(hModule,
+                                                "RtlCaptureStackBackTrace");
+         }
+      }
+      if (pfnCaptureStackBackTrace) {
+         /*
+          * Skip this (debug_backtrace_capture) function's frame.
+          */
+
+         start_frame += 1;
+
+         assert(start_frame + nr_frames < 63);
+         i = pfnCaptureStackBackTrace(start_frame, nr_frames,
+                                      (PVOID *) &backtrace->function, NULL);
+
+         /* Pad remaing requested frames with NULL */
+         while (i < nr_frames) {
+            backtrace[i++].function = NULL;
+         }
+
+         return;
+      }
+   }
+#endif
+
+#if DETECT_ARCH_X86
+#if DETECT_CC_GCC && (DETECT_CC_GCC_VERSION > 404) || defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wframe-address"
+   const void **frame_pointer = ((const void **)__builtin_frame_address(1));
+#pragma GCC diagnostic pop
+#elif DETECT_CC_MSVC
+   const void **frame_pointer;
+   __asm {
+      mov frame_pointer, ebp
+   }
+   frame_pointer = (const void **)frame_pointer[0];
+#else
+   const void **frame_pointer = NULL;
+#endif
+
+   while (nr_frames) {
+      const void **next_frame_pointer;
+
+      if (!frame_pointer)
+         break;
+
+      if (start_frame)
+         --start_frame;
+      else {
+         backtrace[i++].function = frame_pointer[1];
+         --nr_frames;
+      }
+
+      next_frame_pointer = (const void **)frame_pointer[0];
+
+      /* Limit the stack walk to avoid referencing undefined memory */
+      if ((uintptr_t)next_frame_pointer <= (uintptr_t)frame_pointer ||
+          (uintptr_t)next_frame_pointer > (uintptr_t)frame_pointer + 64*1024)
+         break;
+
+      frame_pointer = next_frame_pointer;
+   }
+#endif
+
+   while (nr_frames) {
+      backtrace[i++].function = NULL;
+      --nr_frames;
+   }
+}
+
+static simple_mtx_t backtrace_mutex = SIMPLE_MTX_INITIALIZER;
+
+void
+debug_backtrace_dump(const struct debug_stack_frame *backtrace,
+                     unsigned nr_frames)
+{
+   unsigned i;
+   simple_mtx_lock(&backtrace_mutex);
+   for (i = 0; i < nr_frames; ++i) {
+      if (!backtrace[i].function)
+         break;
+      debug_symbol_print(backtrace[i].function);
+   }
+   simple_mtx_unlock(&backtrace_mutex);
+}
+
+
+void
+debug_backtrace_print(FILE *f,
+                      const struct debug_stack_frame *backtrace,
+                      unsigned nr_frames)
+{
+   unsigned i;
+
+   simple_mtx_lock(&backtrace_mutex);
+   for (i = 0; i < nr_frames; ++i) {
+      const char *symbol;
+      if (!backtrace[i].function)
+         break;
+      symbol = debug_symbol_name_cached(backtrace[i].function);
+      if (symbol)
+         fprintf(f, "%s\n", symbol);
+   }
+   fflush(f);
+   simple_mtx_unlock(&backtrace_mutex);
+}
+
+#endif /* HAVE_LIBUNWIND */