static void
faulthandler_alarm(int signum)
{
PyThreadState *tstate;
const char* errmsg;
int ok;
_Py_write_noraise(fault_alarm.fd,
fault_alarm.header, fault_alarm.header_len);
/* PyThreadState_Get() doesn't give the state of the current thread if
the thread doesn't hold the GIL. Read the thread local storage (TLS)
instead: call PyGILState_GetThisThreadState(). */
tstate = PyGILState_GetThisThreadState();
errmsg = _Py_DumpTracebackThreads(fault_alarm.fd, fault_alarm.interp, tstate);
ok = (errmsg == NULL);
if (ok && fault_alarm.repeat)
alarm(fault_alarm.timeout);
else
/* don't call Py_CLEAR() here because it may call _Py_Dealloc() which
is not signal safe */
alarm(0);
if (fault_alarm.exit)
_exit(1);
}
void
_Py_DumpDecimal(int fd, unsigned long value)
{
/* maximum number of characters required for output of %lld or %p.
We need at most ceil(log10(256)*SIZEOF_LONG_LONG) digits,
plus 1 for the null byte. 53/22 is an upper bound for log10(256). */
char buffer[1 + (sizeof(unsigned long)*53-1) / 22 + 1];
char *ptr, *end;
end = &buffer[Py_ARRAY_LENGTH(buffer) - 1];
ptr = end;
*ptr = '\0';
do {
--ptr;
assert(ptr >= buffer);
*ptr = '0' + (value % 10);
value /= 10;
} while (value);
_Py_write_noraise(fd, ptr, end - ptr);
}
static void
dump_hexadecimal(int fd, unsigned long value, Py_ssize_t width)
{
char buffer[sizeof(unsigned long) * 2 + 1], *ptr, *end;
const Py_ssize_t size = Py_ARRAY_LENGTH(buffer) - 1;
if (width > size)
width = size;
end = &buffer[size];
ptr = end;
*ptr = '\0';
do {
--ptr;
assert(ptr >= buffer);
*ptr = Py_hexdigits[value & 15];
value >>= 4;
} while ((end - ptr) < width || value);
_Py_write_noraise(fd, ptr, end - ptr);
}
static void
faulthandler_thread(void *unused)
{
PyLockStatus st;
const char* errmsg;
int ok;
#if defined(HAVE_PTHREAD_SIGMASK) && !defined(HAVE_BROKEN_PTHREAD_SIGMASK)
sigset_t set;
/* we don't want to receive any signal */
sigfillset(&set);
pthread_sigmask(SIG_SETMASK, &set, NULL);
#endif
do {
st = PyThread_acquire_lock_timed(thread.cancel_event,
thread.timeout_us, 0);
if (st == PY_LOCK_ACQUIRED) {
PyThread_release_lock(thread.cancel_event);
break;
}
/* Timeout => dump traceback */
assert(st == PY_LOCK_FAILURE);
_Py_write_noraise(thread.fd, thread.header, (int)thread.header_len);
errmsg = _Py_DumpTracebackThreads(thread.fd, thread.interp, NULL);
ok = (errmsg == NULL);
if (thread.exit)
_exit(1);
} while (ok && thread.repeat);
/* The only way out */
PyThread_release_lock(thread.running);
}
void
_Py_DumpASCII(int fd, PyObject *text)
{
PyASCIIObject *ascii = (PyASCIIObject *)text;
Py_ssize_t i, size;
int truncated;
int kind;
void *data = NULL;
wchar_t *wstr = NULL;
Py_UCS4 ch;
if (!PyUnicode_Check(text))
return;
size = ascii->length;
kind = ascii->state.kind;
if (kind == PyUnicode_WCHAR_KIND) {
wstr = ((PyASCIIObject *)text)->wstr;
if (wstr == NULL)
return;
size = ((PyCompactUnicodeObject *)text)->wstr_length;
}
else if (ascii->state.compact) {
if (ascii->state.ascii)
data = ((PyASCIIObject*)text) + 1;
else
data = ((PyCompactUnicodeObject*)text) + 1;
}
else {
data = ((PyUnicodeObject *)text)->data.any;
if (data == NULL)
return;
}
if (MAX_STRING_LENGTH < size) {
size = MAX_STRING_LENGTH;
truncated = 1;
}
else {
truncated = 0;
}
for (i=0; i < size; i++) {
if (kind != PyUnicode_WCHAR_KIND)
ch = PyUnicode_READ(kind, data, i);
else
ch = wstr[i];
if (' ' <= ch && ch <= 126) {
/* printable ASCII character */
char c = (char)ch;
_Py_write_noraise(fd, &c, 1);
}
else if (ch <= 0xff) {
PUTS(fd, "\\x");
_Py_DumpHexadecimal(fd, ch, 2);
}
else if (ch <= 0xffff) {
PUTS(fd, "\\u");
_Py_DumpHexadecimal(fd, ch, 4);
}
else {
PUTS(fd, "\\U");
_Py_DumpHexadecimal(fd, ch, 8);
}
}
if (truncated) {
PUTS(fd, "...");
}
}
/*
* This function is code executed in the child process immediately after fork
* to set things up and call exec().
*
* All of the code in this function must only use async-signal-safe functions,
* listed at `man 7 signal` or
* http://www.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_04.html.
*
* This restriction is documented at
* http://www.opengroup.org/onlinepubs/009695399/functions/fork.html.
*/
static void
child_exec(char *const exec_array[],
char *const argv[],
char *const envp[],
const char *cwd,
int p2cread, int p2cwrite,
int c2pread, int c2pwrite,
int errread, int errwrite,
int errpipe_read, int errpipe_write,
int close_fds, int restore_signals,
int call_setsid,
PyObject *py_fds_to_keep,
PyObject *preexec_fn,
PyObject *preexec_fn_args_tuple)
{
int i, saved_errno, reached_preexec = 0;
PyObject *result;
const char* err_msg = "";
/* Buffer large enough to hold a hex integer. We can't malloc. */
char hex_errno[sizeof(saved_errno)*2+1];
if (make_inheritable(py_fds_to_keep, errpipe_write) < 0)
goto error;
/* Close parent's pipe ends. */
if (p2cwrite != -1)
POSIX_CALL(close(p2cwrite));
if (c2pread != -1)
POSIX_CALL(close(c2pread));
if (errread != -1)
POSIX_CALL(close(errread));
POSIX_CALL(close(errpipe_read));
/* When duping fds, if there arises a situation where one of the fds is
either 0, 1 or 2, it is possible that it is overwritten (#12607). */
if (c2pwrite == 0)
POSIX_CALL(c2pwrite = dup(c2pwrite));
if (errwrite == 0 || errwrite == 1)
POSIX_CALL(errwrite = dup(errwrite));
/* Dup fds for child.
dup2() removes the CLOEXEC flag but we must do it ourselves if dup2()
would be a no-op (issue #10806). */
if (p2cread == 0) {
if (_Py_set_inheritable(p2cread, 1, NULL) < 0)
goto error;
}
else if (p2cread != -1)
POSIX_CALL(dup2(p2cread, 0)); /* stdin */
if (c2pwrite == 1) {
if (_Py_set_inheritable(c2pwrite, 1, NULL) < 0)
goto error;
}
else if (c2pwrite != -1)
POSIX_CALL(dup2(c2pwrite, 1)); /* stdout */
if (errwrite == 2) {
if (_Py_set_inheritable(errwrite, 1, NULL) < 0)
goto error;
}
else if (errwrite != -1)
POSIX_CALL(dup2(errwrite, 2)); /* stderr */
/* Close pipe fds. Make sure we don't close the same fd more than */
/* once, or standard fds. */
if (p2cread > 2)
POSIX_CALL(close(p2cread));
if (c2pwrite > 2 && c2pwrite != p2cread)
POSIX_CALL(close(c2pwrite));
if (errwrite != c2pwrite && errwrite != p2cread && errwrite > 2)
POSIX_CALL(close(errwrite));
if (cwd)
POSIX_CALL(chdir(cwd));
if (restore_signals)
_Py_RestoreSignals();
#ifdef HAVE_SETSID
if (call_setsid)
POSIX_CALL(setsid());
#endif
reached_preexec = 1;
if (preexec_fn != Py_None && preexec_fn_args_tuple) {
/* This is where the user has asked us to deadlock their program. */
result = PyObject_Call(preexec_fn, preexec_fn_args_tuple, NULL);
if (result == NULL) {
/* Stringifying the exception or traceback would involve
* memory allocation and thus potential for deadlock.
* We've already faced potential deadlock by calling back
* into Python in the first place, so it probably doesn't
* matter but we avoid it to minimize the possibility. */
err_msg = "Exception occurred in preexec_fn.";
errno = 0; /* We don't want to report an OSError. */
goto error;
}
/* Py_DECREF(result); - We're about to exec so why bother? */
}
/* close FDs after executing preexec_fn, which might open FDs */
if (close_fds) {
/* TODO HP-UX could use pstat_getproc() if anyone cares about it. */
_close_open_fds(3, py_fds_to_keep);
}
/* This loop matches the Lib/os.py _execvpe()'s PATH search when */
/* given the executable_list generated by Lib/subprocess.py. */
saved_errno = 0;
for (i = 0; exec_array[i] != NULL; ++i) {
const char *executable = exec_array[i];
if (envp) {
execve(executable, argv, envp);
} else {
execv(executable, argv);
}
if (errno != ENOENT && errno != ENOTDIR && saved_errno == 0) {
saved_errno = errno;
}
}
/* Report the first exec error, not the last. */
if (saved_errno)
errno = saved_errno;
error:
saved_errno = errno;
/* Report the posix error to our parent process. */
/* We ignore all write() return values as the total size of our writes is
less than PIPEBUF and we cannot do anything about an error anyways.
Use _Py_write_noraise() to retry write() if it is interrupted by a
signal (fails with EINTR). */
if (saved_errno) {
char *cur;
_Py_write_noraise(errpipe_write, "OSError:", 8);
cur = hex_errno + sizeof(hex_errno);
while (saved_errno != 0 && cur > hex_errno) {
*--cur = Py_hexdigits[saved_errno % 16];
saved_errno /= 16;
}
_Py_write_noraise(errpipe_write, cur, hex_errno + sizeof(hex_errno) - cur);
_Py_write_noraise(errpipe_write, ":", 1);
if (!reached_preexec) {
/* Indicate to the parent that the error happened before exec(). */
_Py_write_noraise(errpipe_write, "noexec", 6);
}
/* We can't call strerror(saved_errno). It is not async signal safe.
* The parent process will look the error message up. */
} else {
_Py_write_noraise(errpipe_write, "SubprocessError:0:", 18);
_Py_write_noraise(errpipe_write, err_msg, strlen(err_msg));
}
}
