PR 48931 Make backtrace async-signal-safe, reformat output

From-SVN: r174030
This commit is contained in:
Janne Blomqvist 2011-05-22 19:38:05 +03:00
parent 15f072f97b
commit eec2794c17
6 changed files with 180 additions and 175 deletions

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@ -1,3 +1,20 @@
2011-05-22 Janne Blomqvist <jb@gcc.gnu.org>
PR libfortran/48931
* configure.ac: Check for backtrace_symbols_fd instead of
backtrace_symbols, check for readlink.
* config.h.in: Regenerated.
* configure: Regenerated.
* runtime/backtrace.c (local_strcasestr): Remove.
(bt_header): New function.
(dump_glibc_backtrace): Remove.
(fd_gets): New function.
(show_backtrace): Rework to use backtrace_symbols_fd and pipes
avoiding functions that are not async-signal-safe, reformat
output.
* runtime/main.c (store_exe_path): Try to check /proc/self/exe
first.
2011-05-20 Janne Blomqvist <jb@gcc.gnu.org>
Uros Bizjak <ubizjak@gmail.com>

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@ -84,8 +84,8 @@
/* Define to 1 if you have the `backtrace' function. */
#undef HAVE_BACKTRACE
/* Define to 1 if you have the `backtrace_symbols' function. */
#undef HAVE_BACKTRACE_SYMBOLS
/* Define to 1 if you have the `backtrace_symbols_fd' function. */
#undef HAVE_BACKTRACE_SYMBOLS_FD
/* Define if powf is broken. */
#undef HAVE_BROKEN_POWF
@ -639,6 +639,9 @@
/* Define to 1 if you have the <pwd.h> header file. */
#undef HAVE_PWD_H
/* Define to 1 if you have the `readlink' function. */
#undef HAVE_READLINK
/* libm includes round */
#undef HAVE_ROUND

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@ -16458,7 +16458,7 @@ _ACEOF
fi
done
for ac_func in clock_gettime strftime
for ac_func in clock_gettime strftime readlink
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
@ -16473,7 +16473,7 @@ done
# Check for glibc backtrace functions
for ac_func in backtrace backtrace_symbols
for ac_func in backtrace backtrace_symbols_fd
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

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@ -264,10 +264,10 @@ AC_CHECK_FUNCS(sleep time ttyname signal alarm clock access fork execl)
AC_CHECK_FUNCS(wait setmode execvp pipe dup2 close fdopen strcasestr getrlimit)
AC_CHECK_FUNCS(gettimeofday stat fstat lstat getpwuid vsnprintf dup getcwd)
AC_CHECK_FUNCS(localtime_r gmtime_r strerror_r getpwuid_r ttyname_r)
AC_CHECK_FUNCS(clock_gettime strftime)
AC_CHECK_FUNCS(clock_gettime strftime readlink)
# Check for glibc backtrace functions
AC_CHECK_FUNCS(backtrace backtrace_symbols)
AC_CHECK_FUNCS(backtrace backtrace_symbols_fd)
# Check libc for getgid, getpid, getuid
AC_CHECK_LIB([c],[getgid],[AC_DEFINE([HAVE_GETGID],[1],[libc includes getgid])])

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@ -54,59 +54,57 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#define CAN_FORK (defined(HAVE_FORK) && defined(HAVE_EXECVP) \
&& defined(HAVE_WAIT))
#define GLIBC_BACKTRACE (defined(HAVE_BACKTRACE) \
&& defined(HAVE_BACKTRACE_SYMBOLS))
&& defined(HAVE_BACKTRACE_SYMBOLS_FD))
#define CAN_PIPE (CAN_FORK && defined(HAVE_PIPE) \
&& defined(HAVE_DUP2) && defined(HAVE_FDOPEN) \
&& defined(HAVE_CLOSE))
#if GLIBC_BACKTRACE && CAN_PIPE
/* GDB style #NUM index for each stack frame. */
static void
bt_header (int num)
{
st_printf (" #%d ", num);
}
/* 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. */
static char *
local_strcasestr (const char *s1, const char *s2)
fd_gets (char *s, int size, int fd)
{
#ifdef HAVE_STRCASESTR
return strcasestr (s1, s2);
#else
const char *p = s1;
const size_t len = strlen (s2);
const char u = *s2, v = isupper((int) *s2) ? tolower((int) *s2)
: (islower((int) *s2) ? toupper((int) *s2)
: *s2);
while (1)
for (int i = 0; i < size; i++)
{
while (*p != u && *p != v && *p)
p++;
if (*p == 0)
return NULL;
if (strncasecmp (p, s2, len) == 0)
return (char *)p;
char c;
ssize_t nread = read (fd, &c, 1);
if (nread == 1)
{
s[i] = c;
if (c == '\n')
{
if (i + 1 < size)
s[i+1] = '\0';
else
s[i] = '\0';
break;
}
}
else
{
s[i] = '\0';
break;
}
}
#endif
return s;
}
#endif
#if GLIBC_BACKTRACE
static void
dump_glibc_backtrace (int depth, char *str[])
{
int i;
for (i = 0; i < depth; i++)
{
estr_write (" + ");
estr_write (str[i]);
estr_write ("\n");
}
free (str);
}
#endif
/* show_backtrace displays the backtrace, currently obtained by means of
the glibc backtrace* functions. */
void
show_backtrace (void)
{
@ -116,63 +114,48 @@ show_backtrace (void)
#define BUFSIZE 1024
void *trace[DEPTH];
char **str;
int depth;
depth = backtrace (trace, DEPTH);
if (depth <= 0)
return;
str = backtrace_symbols (trace, depth);
#if CAN_PIPE
#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
#define STDOUT_FILENO 1
#endif
#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif
/* We attempt to extract file and line information from addr2line. */
do
{
/* Local variables. */
int f[2], pid, line, i;
FILE *output;
char addr_buf[DEPTH][GFC_XTOA_BUF_SIZE], func[BUFSIZE], file[BUFSIZE];
char *p, *end;
const char *addr[DEPTH];
/* Write the list of addresses in hexadecimal format. */
for (i = 0; i < depth; i++)
addr[i] = gfc_xtoa ((GFC_UINTEGER_LARGEST) (intptr_t) trace[i], addr_buf[i],
sizeof (addr_buf[i]));
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 5
char *arg[DEPTH+NUM_FIXEDARGS+1];
#define NUM_FIXEDARGS 7
char *arg[NUM_FIXEDARGS];
close (f[0]);
close (STDIN_FILENO);
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 (0);
_exit (1);
close (f[1]);
arg[0] = (char *) "addr2line";
@ -180,112 +163,111 @@ show_backtrace (void)
arg[2] = full_exe_path ();
arg[3] = (char *) "-f";
arg[4] = (char *) "-s";
for (i = 0; i < depth; i++)
arg[NUM_FIXEDARGS+i] = (char *) addr[i];
arg[NUM_FIXEDARGS+depth] = NULL;
arg[5] = (char *) "-C";
arg[6] = NULL;
execvp (arg[0], arg);
_exit (0);
_exit (1);
#undef NUM_FIXEDARGS
}
/* Father process. */
close (f[1]);
wait (NULL);
output = fdopen (f[0], "r");
i = -1;
close (inp[0]);
if (pipe (bt) != 0)
break;
backtrace_symbols_fd (trace, depth, bt[1]);
close (bt[1]);
if (fgets (func, sizeof(func), output))
estr_write ("\nBacktrace for this error:\n");
for (int j = 0; j < depth; j++)
{
estr_write ("\nBacktrace for this error:\n");
const char *addr = gfc_xtoa
((GFC_UINTEGER_LARGEST) (intptr_t) trace[j],
addr_buf, sizeof (addr_buf));
do
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] == '?')
{
if (! fgets (file, sizeof(file), output))
goto fallback;
i++;
for (p = func; *p != '\n' && *p != '\r'; p++)
;
*p = '\0';
/* Try to recognize the internal libgfortran functions. */
if (strncasecmp (func, "*_gfortran", 10) == 0
|| strncasecmp (func, "_gfortran", 9) == 0
|| strcmp (func, "main") == 0 || strcmp (func, "_start") == 0
|| strcmp (func, "_gfortrani_backtrace_handler") == 0)
continue;
if (local_strcasestr (str[i], "libgfortran.so") != NULL
|| local_strcasestr (str[i], "libgfortran.dylib") != NULL
|| local_strcasestr (str[i], "libgfortran.a") != NULL)
continue;
/* If we only have the address, use the glibc backtrace. */
if (func[0] == '?' && func[1] == '?' && file[0] == '?'
&& file[1] == '?')
bt_header (j);
while (1)
{
estr_write (" + ");
estr_write (str[i]);
estr_write ("\n");
continue;
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;
}
/* Extract the line number. */
for (end = NULL, p = file; *p; p++)
if (*p == ':')
end = p;
if (end != NULL)
{
*end = '\0';
line = atoi (++end);
}
else
line = -1;
if (strcmp (func, "MAIN__") == 0)
estr_write (" + in the main program\n");
else
{
estr_write (" + function ");
estr_write (func);
estr_write (" (0x");
estr_write (addr[i]);
estr_write (")\n");
}
if (line <= 0 && strcmp (file, "??") == 0)
continue;
if (line <= 0)
{
estr_write (" from file ");
estr_write (file);
estr_write ("\n");
}
else
st_printf (" at line %d of file %s\n", line, file);
}
while (fgets (func, sizeof(func), output));
free (str);
return;
/* _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;
fallback:
estr_write ("** Something went wrong while running addr2line. **\n"
"** Falling back to a simpler backtrace scheme. **\n");
}
}
estr_write ("** Something went wrong while running addr2line. **\n"
"** Falling back to a simpler backtrace scheme. **\n");
}
while (0);
#undef DEPTH
#undef BUFSIZE
#endif
#endif
#endif /* CAN_PIPE */
#if CAN_FORK && defined(HAVE_GETPPID)
/* 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
{
@ -312,15 +294,9 @@ fallback:
execvp (arg[0], arg);
#undef NUM_ARGS
/* pstack didn't work, so we fall back to dumping the glibc
backtrace if we can. */
#if GLIBC_BACKTRACE
dump_glibc_backtrace (depth, str);
#else
/* pstack didn't work. */
estr_write (" unable to produce a backtrace, sorry!\n");
#endif
_exit (0);
_exit (1);
}
/* Father process. */
@ -328,13 +304,7 @@ fallback:
return;
}
while(0);
#endif
#if GLIBC_BACKTRACE
/* Fallback to the glibc backtrace. */
estr_write ("\nBacktrace for this error:\n");
dump_glibc_backtrace (depth, str);
return;
#endif
#else
estr_write ("\nBacktrace not yet available on this platform, sorry!\n");
#endif
}

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@ -92,6 +92,19 @@ store_exe_path (const char * argv0)
if (please_free_exe_path_when_done)
free ((char *) exe_path);
/* Reading the /proc/self/exe symlink is Linux-specific(?), but if
it works it gives the correct answer. */
#ifdef HAVE_READLINK
int len;
if ((len = readlink ("/proc/self/exe", buf, sizeof (buf) - 1)) != -1)
{
buf[len] = '\0';
exe_path = strdup (buf);
please_free_exe_path_when_done = 1;
return;
}
#endif
/* On the simulator argv is not set. */
if (argv0 == NULL || argv0[0] == '/')
{
@ -107,7 +120,9 @@ store_exe_path (const char * argv0)
cwd = "";
#endif
/* exe_path will be cwd + "/" + argv[0] + "\0" */
/* exe_path will be cwd + "/" + argv[0] + "\0". This will not work
if the executable is not in the cwd, but at this point we're out
of better ideas. */
size_t pathlen = strlen (cwd) + 1 + strlen (argv0) + 1;
path = malloc (pathlen);
snprintf (path, pathlen, "%s%c%s", cwd, DIR_SEPARATOR, argv0);