-/* Copyright (C) 2006, 2007, 2009, 2011 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 <string.h>
-
-#ifdef HAVE_STDLIB_H
-#include <stdlib.h>
-#endif
+#include <gthr.h>
-#ifdef HAVE_INTTYPES_H
-#include <inttypes.h>
-#endif
+#include <string.h>
+#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
-#ifdef HAVE_EXECINFO_H
-#include <execinfo.h>
-#endif
-
-#ifdef HAVE_SYS_WAIT_H
-#include <sys/wait.h>
-#endif
-
-#include <ctype.h>
+#include "backtrace-supported.h"
+#include "backtrace.h"
-/* Macros for common sets of capabilities: can we fork and exec, can
- we use glibc-style backtrace functions, and can we use pipes. */
-#define CAN_FORK (defined(HAVE_FORK) && defined(HAVE_EXECVP) \
- && defined(HAVE_WAIT))
-#define GLIBC_BACKTRACE (defined(HAVE_BACKTRACE) \
- && defined(HAVE_BACKTRACE_SYMBOLS_FD))
-#define CAN_PIPE (CAN_FORK && defined(HAVE_PIPE) \
- && defined(HAVE_DUP2) && defined(HAVE_FDOPEN) \
- && defined(HAVE_CLOSE))
+/* 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;
+}
+
+static int
+full_callback (void *data, uintptr_t pc, const char *filename,
+ int lineno, const char *function)
+{
+ 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;
}
-/* show_backtrace displays the backtrace, currently obtained by means of
- the glibc backtrace* functions. */
+/* Display the backtrace. */
void
-show_backtrace (void)
+show_backtrace (bool in_signal_handler)
{
-#if GLIBC_BACKTRACE
+ struct backtrace_state *lbstate;
+ struct mystate state = { 0, false, in_signal_handler };
+
+ lbstate = backtrace_create_state (NULL, __gthread_active_p (),
+ error_callback, NULL);
-#define DEPTH 50
-#define BUFSIZE 1024
+ if (lbstate == NULL)
+ return;
- void *trace[DEPTH];
- int depth;
+ if (!BACKTRACE_SUPPORTED || (in_signal_handler && BACKTRACE_USES_MALLOC))
+ {
+ /* 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. */
- depth = backtrace (trace, DEPTH);
- if (depth <= 0)
- return;
+ backtrace_simple (lbstate, 0, simple_callback, error_callback, &state);
+ }
+ else
+ {
+ /* 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 CAN_PIPE
-
- /* We attempt to extract file and line information from addr2line. */
- do
- {
- /* Local variables. */
- int f[2], pid, bt[2], inp[2];
- char addr_buf[GFC_XTOA_BUF_SIZE], func[BUFSIZE], file[BUFSIZE];
- char *p;
-
- /* Don't output an error message if something goes wrong, we'll simply
- fall back to the pstack and glibc backtraces. */
- 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];
-
- 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] = (char *) "addr2line";
- arg[1] = (char *) "-e";
- arg[2] = full_exe_path ();
- arg[3] = (char *) "-f";
- arg[4] = (char *) "-s";
- arg[5] = (char *) "-C";
- arg[6] = NULL;
- execvp (arg[0], arg);
- _exit (1);
-#undef NUM_FIXEDARGS
- }
-
- /* Father process. */
- close (f[1]);
- close (inp[0]);
- if (pipe (bt) != 0)
- break;
- backtrace_symbols_fd (trace, depth, bt[1]);
- close (bt[1]);
-
- estr_write ("\nBacktrace for this error:\n");
- for (int j = 0; j < depth; j++)
- {
- const char *addr = gfc_xtoa
- ((GFC_UINTEGER_LARGEST) (intptr_t) trace[j],
- addr_buf, sizeof (addr_buf));
-
- write (inp[1], addr, strlen (addr));
- write (inp[1], "\n", 1);
-
- if (! fd_gets (func, sizeof(func), f[0]))
- goto fallback;
- if (! fd_gets (file, sizeof(file), f[0]))
- goto fallback;
-
- for (p = func; *p != '\n' && *p != '\r'; p++)
- ;
- *p = '\0';
-
- /* If we only have the address, use the glibc backtrace. */
- if (func[0] == '?' && func[1] == '?' && file[0] == '?'
- && file[1] == '?')
- {
- bt_header (j);
- while (1)
- {
- char bc;
- ssize_t nread = read (bt[0], &bc, 1);
- if (nread != 1 || bc == '\n')
- break;
- write (STDERR_FILENO, &bc, 1);
- }
- estr_write ("\n");
- continue;
- }
- else
- {
- /* Forward to the next entry in the backtrace. */
- while (1)
- {
- char bc;
- ssize_t nread = read (bt[0], &bc, 1);
- if (nread != 1 || bc == '\n')
- break;
- }
- }
-
- /* _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)
- break;
-
- bt_header (j);
- estr_write (full_exe_path ());
- estr_write ("[0x");
- estr_write (addr);
- estr_write ("] in ");
- estr_write (func);
-
- if (strncmp (file, "??", 2) == 0)
- estr_write ("\n");
- else
- {
- estr_write (" at ");
- estr_write (file);
- }
- } /* Loop over each hex address. */
- close (inp[1]);
- close (bt[0]);
- wait (NULL);
- return;
+ backtrace_full (lbstate, 0, full_callback, error_callback, &state);
+ if (state.try_simple)
+ backtrace_simple (lbstate, 0, simple_callback, error_callback, &state);
+ }
+}
-fallback:
- estr_write ("** Something went wrong while running addr2line. **\n"
- "** Falling back to a simpler backtrace scheme. **\n");
- }
- while (0);
-
-#undef DEPTH
-#undef BUFSIZE
-
-#endif /* CAN_PIPE */
-
- /* Fallback to the glibc backtrace. */
- estr_write ("\nBacktrace for this error:\n");
- backtrace_symbols_fd (trace, depth, STDERR_FILENO);
- return;
-
-#elif defined(CAN_FORK) && defined(HAVE_GETPPID)
- /* Try to call pstack. */
- do
- {
- /* Local variables. */
- int pid;
-
- /* Don't output an error message if something goes wrong, we'll simply
- fall back to the pstack and glibc backtraces. */
- if ((pid = fork ()) == -1)
- break;
-
- if (pid == 0)
- {
- /* Child process. */
-#define NUM_ARGS 2
- char *arg[NUM_ARGS+1];
- char buf[20];
-
- estr_write ("\nBacktrace for this error:\n");
- arg[0] = (char *) "pstack";
- snprintf (buf, sizeof(buf), "%d", (int) getppid ());
- arg[1] = buf;
- arg[2] = NULL;
- execvp (arg[0], arg);
-#undef NUM_ARGS
-
- /* pstack didn't work. */
- estr_write (" unable to produce a backtrace, sorry!\n");
- _exit (1);
- }
-
- /* Father process. */
- wait (NULL);
- return;
- }
- while(0);
-#else
- estr_write ("\nBacktrace not yet available on this platform, sorry!\n");
-#endif
+
+
+/* Function called by the front-end translating the BACKTRACE intrinsic. */
+
+extern void backtrace (void);
+export_proto (backtrace);
+
+void
+backtrace (void)
+{
+ show_backtrace (false);
}
+
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