src/coredump/stacktrace.c

   1 /***
   2   This file is part of systemd.
   3
   4   Copyright 2014 Lennart Poettering
   5
   6   systemd is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as published by
   8   the Free Software Foundation; either version 2.1 of the License, or
   9   (at your option) any later version.
  10
  11   systemd is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   Lesser General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <dwarf.h>
  21 #include <elfutils/libdwfl.h>
  22
  23 #include "alloc-util.h"
  24 #include "fd-util.h"
  25 #include "format-util.h"
  26 #include "macro.h"
  27 #include "stacktrace.h"
  28 #include "string-util.h"
  29 #include "util.h"
  30
  31 #define FRAMES_MAX 64
  32 #define THREADS_MAX 64
  33
  34 struct stack_context {
  35         FILE *f;
  36         Dwfl *dwfl;
  37         Elf *elf;
  38         unsigned n_thread;
  39         unsigned n_frame;
  40 };
  41
  42 static int frame_callback(Dwfl_Frame *frame, void *userdata) {
  43         struct stack_context *c = userdata;
  44         Dwarf_Addr pc, pc_adjusted, bias = 0;
  45         _cleanup_free_ Dwarf_Die *scopes = NULL;
  46         const char *fname = NULL, *symbol = NULL;
  47         Dwfl_Module *module;
  48         bool is_activation;
  49
  50         assert(frame);
  51         assert(c);
  52
  53         if (c->n_frame >= FRAMES_MAX)
  54                 return DWARF_CB_ABORT;
  55
  56         if (!dwfl_frame_pc(frame, &pc, &is_activation))
  57                 return DWARF_CB_ABORT;
  58
  59         pc_adjusted = pc - (is_activation ? 0 : 1);
  60
  61         module = dwfl_addrmodule(c->dwfl, pc_adjusted);
  62         if (module) {
  63                 Dwarf_Die *s, *cudie;
  64                 int n;
  65
  66                 cudie = dwfl_module_addrdie(module, pc_adjusted, &bias);
  67                 if (cudie) {
  68                         n = dwarf_getscopes(cudie, pc_adjusted - bias, &scopes);
  69                         for (s = scopes; s < scopes + n; s++) {
  70                                 if (IN_SET(dwarf_tag(s), DW_TAG_subprogram, DW_TAG_inlined_subroutine, DW_TAG_entry_point)) {
  71                                         Dwarf_Attribute *a, space;
  72
  73                                         a = dwarf_attr_integrate(s, DW_AT_MIPS_linkage_name, &space);
  74                                         if (!a)
  75                                                 a = dwarf_attr_integrate(s, DW_AT_linkage_name, &space);
  76                                         if (a)
  77                                                 symbol = dwarf_formstring(a);
  78                                         if (!symbol)
  79                                                 symbol = dwarf_diename(s);
  80
  81                                         if (symbol)
  82                                                 break;
  83                                 }
  84                         }
  85                 }
  86
  87                 if (!symbol)
  88                         symbol = dwfl_module_addrname(module, pc_adjusted);
  89
  90                 fname = dwfl_module_info(module, NULL, NULL, NULL, NULL, NULL, NULL, NULL);
  91         }
  92
  93         fprintf(c->f, "#%-2u 0x%016" PRIx64 " %s (%s)\n", c->n_frame, (uint64_t) pc, strna(symbol), strna(fname));
  94         c->n_frame++;
  95
  96         return DWARF_CB_OK;
  97 }
  98
  99 static int thread_callback(Dwfl_Thread *thread, void *userdata) {
 100         struct stack_context *c = userdata;
 101         pid_t tid;
 102
 103         assert(thread);
 104         assert(c);
 105
 106         if (c->n_thread >= THREADS_MAX)
 107                 return DWARF_CB_ABORT;
 108
 109         if (c->n_thread != 0)
 110                 fputc('\n', c->f);
 111
 112         c->n_frame = 0;
 113
 114         tid = dwfl_thread_tid(thread);
 115         fprintf(c->f, "Stack trace of thread " PID_FMT ":\n", tid);
 116
 117         if (dwfl_thread_getframes(thread, frame_callback, c) < 0)
 118                 return DWARF_CB_ABORT;
 119
 120         c->n_thread++;
 121
 122         return DWARF_CB_OK;
 123 }
 124
 125 int coredump_make_stack_trace(int fd, const char *executable, char **ret) {
 126
 127         static const Dwfl_Callbacks callbacks = {
 128                 .find_elf = dwfl_build_id_find_elf,
 129                 .find_debuginfo = dwfl_standard_find_debuginfo,
 130         };
 131
 132         struct stack_context c = {};
 133         char *buf = NULL;
 134         size_t sz = 0;
 135         int r;
 136
 137         assert(fd >= 0);
 138         assert(ret);
 139
 140         if (lseek(fd, 0, SEEK_SET) == (off_t) -1)
 141                 return -errno;
 142
 143         c.f = open_memstream(&buf, &sz);
 144         if (!c.f)
 145                 return -ENOMEM;
 146
 147         elf_version(EV_CURRENT);
 148
 149         c.elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);
 150         if (!c.elf) {
 151                 r = -EINVAL;
 152                 goto finish;
 153         }
 154
 155         c.dwfl = dwfl_begin(&callbacks);
 156         if (!c.dwfl) {
 157                 r = -EINVAL;
 158                 goto finish;
 159         }
 160
 161         if (dwfl_core_file_report(c.dwfl, c.elf, executable) < 0) {
 162                 r = -EINVAL;
 163                 goto finish;
 164         }
 165
 166         if (dwfl_report_end(c.dwfl, NULL, NULL) != 0) {
 167                 r = -EINVAL;
 168                 goto finish;
 169         }
 170
 171         if (dwfl_core_file_attach(c.dwfl, c.elf) < 0) {
 172                 r = -EINVAL;
 173                 goto finish;
 174         }
 175
 176         if (dwfl_getthreads(c.dwfl, thread_callback, &c) < 0) {
 177                 r = -EINVAL;
 178                 goto finish;
 179         }
 180
 181         c.f = safe_fclose(c.f);
 182
 183         *ret = buf;
 184         buf = NULL;
 185
 186         r = 0;
 187
 188 finish:
 189         if (c.dwfl)
 190                 dwfl_end(c.dwfl);
 191
 192         if (c.elf)
 193                 elf_end(c.elf);
 194
 195         safe_fclose(c.f);
 196
 197         free(buf);
 198
 199         return r;
 200 }