lib/backtrace.h

   1 /*
   2  * Copyright (c) 2009 Nicira, Inc.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef BACKTRACE_H
  18 #define BACKTRACE_H 1
  19
  20 #include <stdint.h>
  21 #include "openvswitch/dynamic-string.h"
  22
  23 #ifdef HAVE_UNWIND
  24 #define UNW_LOCAL_ONLY
  25 #include <libunwind.h>
  26 #endif
  27
  28 /* log_backtrace() will save the backtrace of a running program
  29  * into the log at the DEBUG level.
  30  *
  31  * To use it, insert the following code to where backtrace is
  32  * desired:
  33  *       #include "backtrace.h"
  34  *
  35  *       log_backtrace();                           <-- plain
  36  *       log_backtrace_msg("your message");         <-- with a message
  37  *
  38  *
  39  * A typical log will look like the following. The hex numbers listed after
  40  * "backtrace" are the addresses of the backtrace.
  41  *
  42  * 2014-03-13T23:18:11.979Z|00002|backtrace(revalidator_6)|ERR|lib/dpif-netdev.c:1312: (backtrace: 0x00521f57 0x00460365 0x00463ea4 0x0046470b 0x0043b32d 0x0043bac3 0x0043bae2 0x0043943b 0x004c22b3 0x2b5b3ac94e9a 0x2b5b3b4a33fd)
  43  *
  44  * The following bash command can be used to  view backtrace in
  45  * a more readable form.
  46  * addr2line -p -e vswitchd/ovs-vswitchd <cut-and-paste back traces>
  47  *
  48  * An typical run and output will look like:
  49  * addr2line -p -e vswitchd/ovs-vswitchd  0x00521f57 0x00460365 0x00463ea4
  50  * 0x0046470b 0x0043b32d 0x0043bac3 0x0043bae2 0x0043943b 0x004c22b3
  51  * 0x2b5b3ac94e9a 0x2b5b3b4a33fd
  52  *
  53  * openvswitch/lib/backtrace.c:33
  54  * openvswitch/lib/dpif-netdev.c:1312
  55  * openvswitch/lib/dpif.c:937
  56  * openvswitch/lib/dpif.c:1258
  57  * openvswitch/ofproto/ofproto-dpif-upcall.c:1440
  58  * openvswitch/ofproto/ofproto-dpif-upcall.c:1595
  59  * openvswitch/ofproto/ofproto-dpif-upcall.c:160
  60  * openvswitch/ofproto/ofproto-dpif-upcall.c:717
  61  * openvswitch/lib/ovs-thread.c:268
  62  * ??:0
  63  * ??:0
  64  */
  65
  66 #define log_backtrace() log_backtrace_at(NULL, OVS_SOURCE_LOCATOR);
  67 #define log_backtrace_msg(msg) log_backtrace_at(msg, OVS_SOURCE_LOCATOR);
  68
  69 #define BACKTRACE_MAX_FRAMES 31
  70
  71 struct backtrace {
  72     int n_frames;
  73     uintptr_t frames[BACKTRACE_MAX_FRAMES];
  74 };
  75
  76 #ifdef HAVE_UNWIND
  77 #define UNW_MAX_DEPTH 32
  78 #define UNW_MAX_FUNCN 32
  79 #define UNW_MAX_BUF \
  80     (UNW_MAX_DEPTH * sizeof(struct unw_backtrace))
  81
  82 struct unw_backtrace {
  83     char func[UNW_MAX_FUNCN];
  84     unw_word_t ip;
  85     unw_word_t offset;
  86 };
  87 #endif
  88
  89 void backtrace_capture(struct backtrace *);
  90 void log_backtrace_at(const char *msg, const char *where);
  91 void log_received_backtrace(int fd);
  92
  93 #endif /* backtrace.h */