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script: improve I/O return code checks 

Handle error based on return code of handle_io() and handle_signal().
Keep SIGTTIN unblocked during read() in handle_io().

Signed-off-by: Soumendra Ganguly <soumendraganguly@gmail.com>
This commit is contained in:
Soumendra Ganguly 2020-09-15 09:14:59 -05:00 committed by Karel Zak
parent 39d16258a1
commit 5c6903b159
1 changed files with 37 additions and 30 deletions
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67
lib/pty-session.c
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@ -340,12 +340,17 @@ static int handle_io(struct ul_pty *pty, int fd, int *eof)
char buf[BUFSIZ];
ssize_t bytes;
int rc = 0;
sigset_t set;
DBG(IO, ul_debugobj(pty, " handle I/O on fd=%d", fd));
*eof = 0;
sigemptyset(&set);
sigaddset(&set, SIGTTIN);
sigprocmask(SIG_UNBLOCK, &set, NULL);
/* read from active FD */
bytes = read(fd, buf, sizeof(buf));
sigprocmask(SIG_BLOCK, &set, NULL);
if (bytes < 0) {
if (errno == EAGAIN || errno == EINTR)
return 0;
@ -409,8 +414,8 @@ void ul_pty_wait_for_child(struct ul_pty *pty)
}
} else {
/* final wait */
while ((pid = wait3(&status, options, NULL)) > 0) {
DBG(SIG, ul_debug(" wait3 done [rc=%d]", (int) pid));
while ((pid = waitpid(-1, &status, options)) > 0) {
DBG(SIG, ul_debug(" waitpid done [rc=%d]", (int) pid));
if (pid == pty->child) {
if (pty->callbacks.child_die)
pty->callbacks.child_die(
@ -451,9 +456,10 @@ static int handle_signal(struct ul_pty *pty, int fd)
else
ul_pty_wait_for_child(pty);
} else if (info.ssi_status == SIGSTOP && pty->child > 0)
} else if (info.ssi_status == SIGSTOP && pty->child > 0) {
pty->callbacks.child_sigstop(pty->callback_data,
pty->child);
}
if (pty->child <= 0) {
DBG(SIG, ul_debugobj(pty, " no child, setting leaving timeout"));
@ -571,16 +577,15 @@ int ul_pty_proxy_master(struct ul_pty *pty)
rc = mainloop_callback(pty);
if (rc == 0)
continue;
} else
} else {
rc = 0;
}
DBG(IO, ul_debugobj(pty, "leaving poll() loop [timeout=%d, rc=%d]", timeout, rc));
break;
}
/* event */
for (i = 0; i < ARRAY_SIZE(pfd); i++) {
rc = 0;
if (pfd[i].revents == 0)
continue;
@ -594,34 +599,36 @@ int ul_pty_proxy_master(struct ul_pty *pty)
pfd[i].revents & POLLERR ? "POLLERR" : "",
pfd[i].revents & POLLNVAL ? "POLLNVAL" : ""));
switch (i) {
case POLLFD_STDIN:
case POLLFD_MASTER:
/* data */
if (pfd[i].revents & POLLIN)
rc = handle_io(pty, pfd[i].fd, &eof);
/* EOF maybe detected in two ways; they are as follows:
* A) poll() return POLLHUP event after close()
* B) read() returns 0 (no data)
*
* POLLNVAL means that fd is closed.
*/
if ((pfd[i].revents & POLLHUP) || (pfd[i].revents & POLLNVAL) || eof) {
DBG(IO, ul_debugobj(pty, " ignore FD"));
pfd[i].fd = -1;
if (i == POLLFD_STDIN) {
ul_pty_write_eof_to_child(pty);
DBG(IO, ul_debugobj(pty, " ignore STDIN"));
}
}
continue;
case POLLFD_SIGNAL:
if (i == POLLFD_SIGNAL)
rc = handle_signal(pty, pfd[i].fd);
else if (pfd[i].revents & POLLIN)
rc = handle_io(pty, pfd[i].fd, &eof); /* data */
if (rc) {
ul_pty_write_eof_to_child(pty);
break;
}
if (rc)
break;
if (i == POLLFD_SIGNAL)
continue;
/* EOF maybe detected in two ways; they are as follows:
* A) poll() return POLLHUP event after close()
* B) read() returns 0 (no data)
*
* POLLNVAL means that fd is closed.
*/
if ((pfd[i].revents & POLLHUP) || (pfd[i].revents & POLLNVAL) || eof) {
DBG(IO, ul_debugobj(pty, " ignore FD"));
pfd[i].fd = -1;
if (i == POLLFD_STDIN) {
ul_pty_write_eof_to_child(pty);
DBG(IO, ul_debugobj(pty, " ignore STDIN"));
}
}
}
if (rc)
break;
}
pty_signals_cleanup(pty);