-/* Copyright (C) 2006-2013 Free Software Foundation, Inc.
+/* Copyright (C) 2006-2018 Free Software Foundation, Inc.
Contributed by François-Xavier Coudert
This file is part of the GNU Fortran runtime library (libgfortran).
#include "libgfortran.h"
+#include <gthr.h>
+
#include <string.h>
-#include <stdlib.h>
+#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
-#ifdef HAVE_SYS_WAIT_H
-#include <sys/wait.h>
-#endif
-
-#include <limits.h>
+#include "backtrace-supported.h"
+#include "backtrace.h"
-#include "unwind.h"
-
-/* Macros for common sets of capabilities: can we fork and exec, and
- can we use pipes to communicate with the subprocess. */
-#define CAN_FORK (defined(HAVE_FORK) && defined(HAVE_EXECVE) \
- && defined(HAVE_WAIT))
-#define CAN_PIPE (CAN_FORK && defined(HAVE_PIPE) \
- && defined(HAVE_DUP2) && defined(HAVE_CLOSE))
-
-#ifndef PATH_MAX
-#define PATH_MAX 4096
-#endif
+/* Store our own state while backtracing. */
+struct mystate
+{
+ int frame;
+ bool try_simple;
+ bool in_signal_handler;
+};
-/* GDB style #NUM index for each stack frame. */
+/* Does a function name have "_gfortran_" or "_gfortrani_" prefix, possibly
+ with additional underscore(s) at the beginning? Cannot use strncmp()
+ because we might be called from a signal handler. */
-static void
-bt_header (int num)
+static int
+has_gfortran_prefix (const char *s)
{
- st_printf ("#%d ", num);
-}
+ if (!s)
+ return 0;
+ while (*s == '_')
+ s++;
-/* fgets()-like function that reads a line from a fd, without
- needing to malloc() a buffer, and does not use locks, hence should
- be async-signal-safe. */
+ return (s[0] == 'g' && s[1] == 'f' && s[2] == 'o' && s[3] == 'r'
+ && s[4] == 't' && s[5] == 'r' && s[6] == 'a' && s[7] == 'n'
+ && (s[8] == '_' || (s[8] == 'i' && s[9] == '_')));
+}
-static char *
-fd_gets (char *s, int size, int fd)
+static void
+error_callback (void *data, const char *msg, int errnum)
{
- for (int i = 0; i < size; i++)
+ struct mystate *state = (struct mystate *) data;
+#define ERRHDR "\nCould not print backtrace: "
+
+ if (errnum < 0)
+ {
+ state->try_simple = true;
+ return;
+ }
+ else if (errnum == 0)
{
- char c;
- ssize_t nread = read (fd, &c, 1);
- if (nread == 1)
+ estr_write (ERRHDR);
+ estr_write (msg);
+ estr_write ("\n");
+ }
+ else
+ {
+ char errbuf[256];
+ if (state->in_signal_handler)
{
- s[i] = c;
- if (c == '\n')
- {
- if (i + 1 < size)
- s[i+1] = '\0';
- else
- s[i] = '\0';
- break;
- }
+ estr_write (ERRHDR);
+ estr_write (msg);
+ estr_write (", errno: ");
+ const char *p = gfc_itoa (errnum, errbuf, sizeof (errbuf));
+ estr_write (p);
+ estr_write ("\n");
}
else
- {
- s[i] = '\0';
- if (i == 0)
- return NULL;
- break;
- }
+ st_printf (ERRHDR "%s: %s\n", msg,
+ gf_strerror (errnum, errbuf, sizeof (errbuf)));
}
- return s;
}
+static int
+simple_callback (void *data, uintptr_t pc)
+{
+ struct mystate *state = (struct mystate *) data;
+ st_printf ("#%d 0x%lx\n", state->frame, (unsigned long) pc);
+ (state->frame)++;
+ return 0;
+}
-extern char *addr2line_path;
-
-/* Struct containing backtrace state. */
-typedef struct
+static int
+full_callback (void *data, uintptr_t pc, const char *filename,
+ int lineno, const char *function)
{
- int frame_number;
- int direct_output;
- int outfd;
- int infd;
- int error;
+ struct mystate *state = (struct mystate *) data;
+
+ if (has_gfortran_prefix (function))
+ return 0;
+
+ st_printf ("#%d 0x%lx in %s\n", state->frame,
+ (unsigned long) pc, function == NULL ? "???" : function);
+ if (filename || lineno != 0)
+ st_printf ("\tat %s:%d\n", filename == NULL ? "???" : filename, lineno);
+ (state->frame)++;
+
+ if (function != NULL && strcmp (function, "main") == 0)
+ return 1;
+
+ return 0;
}
-bt_state;
-static _Unwind_Reason_Code
-trace_function (struct _Unwind_Context *context, void *state_ptr)
+
+/* Display the backtrace. */
+
+void
+show_backtrace (bool in_signal_handler)
{
- bt_state* state = (bt_state*) state_ptr;
- _Unwind_Ptr ip;
-#ifdef HAVE_GETIPINFO
- int ip_before_insn = 0;
- ip = _Unwind_GetIPInfo (context, &ip_before_insn);
-
- /* If the unwinder gave us a 'return' address, roll it back a little
- to ensure we get the correct line number for the call itself. */
- if (! ip_before_insn)
- --ip;
-#else
- ip = _Unwind_GetIP (context);
-#endif
+ struct backtrace_state *lbstate;
+ struct mystate state = { 0, false, in_signal_handler };
+
+ lbstate = backtrace_create_state (NULL, __gthread_active_p (),
+ error_callback, NULL);
+
+ if (lbstate == NULL)
+ return;
- if (state->direct_output)
+ if (!BACKTRACE_SUPPORTED || (in_signal_handler && BACKTRACE_USES_MALLOC))
{
- bt_header(state->frame_number);
- st_printf ("%p\n", (void*) ip);
+ /* If symbolic backtrace is not supported on this target, or would
+ require malloc() and we are in a signal handler, go with a
+ simple backtrace. */
+
+ backtrace_simple (lbstate, 0, simple_callback, error_callback, &state);
}
else
{
- char addr_buf[GFC_XTOA_BUF_SIZE], func[1024], file[PATH_MAX];
- char *p;
- const char* addr = gfc_xtoa (ip, addr_buf, sizeof (addr_buf));
- write (state->outfd, addr, strlen (addr));
- write (state->outfd, "\n", 1);
+ /* libbacktrace uses mmap, which is safe to call from a signal handler
+ (in practice, if not in theory). Thus we can generate a symbolic
+ backtrace, if debug symbols are available. */
- if (! fd_gets (func, sizeof(func), state->infd))
- {
- state->error = 1;
- goto done;
- }
- if (! fd_gets (file, sizeof(file), state->infd))
- {
- state->error = 1;
- goto done;
- }
-
- for (p = func; *p != '\n' && *p != '\r'; p++)
- ;
- *p = '\0';
-
- /* _start is a setup routine that calls main(), and main() is
- the frontend routine that calls some setup stuff and then
- calls MAIN__, so at this point we should stop. */
- if (strcmp (func, "_start") == 0 || strcmp (func, "main") == 0)
- return _URC_END_OF_STACK;
-
- bt_header (state->frame_number);
- estr_write ("0x");
- estr_write (addr);
-
- if (func[0] != '?' && func[1] != '?')
- {
- estr_write (" in ");
- estr_write (func);
- }
-
- if (strncmp (file, "??", 2) == 0)
- estr_write ("\n");
- else
- {
- estr_write (" at ");
- estr_write (file);
- }
+ backtrace_full (lbstate, 0, full_callback, error_callback, &state);
+ if (state.try_simple)
+ backtrace_simple (lbstate, 0, simple_callback, error_callback, &state);
}
+}
- done:
- state->frame_number++;
-
- return _URC_NO_REASON;
-}
+/* Function called by the front-end translating the BACKTRACE intrinsic. */
-/* Display the backtrace. */
+extern void backtrace (void);
+export_proto (backtrace);
void
backtrace (void)
{
- bt_state state;
- state.frame_number = 0;
- state.error = 0;
-
-#if CAN_PIPE
-
- if (addr2line_path == NULL)
- goto fallback_noerr;
-
- /* We attempt to extract file and line information from addr2line. */
- do
- {
- /* Local variables. */
- int f[2], pid, inp[2];
-
- /* Don't output an error message if something goes wrong, we'll simply
- fall back to printing the addresses. */
- if (pipe (f) != 0)
- break;
- if (pipe (inp) != 0)
- break;
- if ((pid = fork ()) == -1)
- break;
-
- if (pid == 0)
- {
- /* Child process. */
-#define NUM_FIXEDARGS 7
- char *arg[NUM_FIXEDARGS];
- char *newenv[] = { NULL };
-
- close (f[0]);
-
- close (inp[1]);
- if (dup2 (inp[0], STDIN_FILENO) == -1)
- _exit (1);
- close (inp[0]);
-
- close (STDERR_FILENO);
-
- if (dup2 (f[1], STDOUT_FILENO) == -1)
- _exit (1);
- close (f[1]);
-
- arg[0] = addr2line_path;
- arg[1] = (char *) "-e";
- arg[2] = full_exe_path ();
- arg[3] = (char *) "-f";
- arg[4] = (char *) "-s";
- arg[5] = (char *) "-C";
- arg[6] = NULL;
- execve (addr2line_path, arg, newenv);
- _exit (1);
-#undef NUM_FIXEDARGS
- }
-
- /* Father process. */
- close (f[1]);
- close (inp[0]);
-
- state.outfd = inp[1];
- state.infd = f[0];
- state.direct_output = 0;
- _Unwind_Backtrace (trace_function, &state);
- if (state.error)
- goto fallback;
- close (inp[1]);
- close (f[0]);
- wait (NULL);
- return;
-
-fallback:
- estr_write ("** Something went wrong while running addr2line. **\n"
- "** Falling back to a simpler backtrace scheme. **\n");
- }
- while (0);
-
-fallback_noerr:
-#endif /* CAN_PIPE */
-
- /* Fallback to the simple backtrace without addr2line. */
- state.direct_output = 1;
- _Unwind_Backtrace (trace_function, &state);
+ show_backtrace (false);
}
-iexport(backtrace);
+
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