632 lines
20 KiB
C
632 lines
20 KiB
C
/* SPDX-License-Identifier: LGPL-2.1+ */
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#include <errno.h>
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#include <limits.h>
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#include <signal.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sys/epoll.h>
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#include <sys/ioctl.h>
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#include <sys/time.h>
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#include <termios.h>
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#include <unistd.h>
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#include "sd-event.h"
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#include "alloc-util.h"
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#include "fd-util.h"
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#include "log.h"
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#include "macro.h"
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#include "ptyfwd.h"
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#include "terminal-util.h"
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#include "time-util.h"
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struct PTYForward {
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sd_event *event;
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int master;
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PTYForwardFlags flags;
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sd_event_source *stdin_event_source;
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sd_event_source *stdout_event_source;
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sd_event_source *master_event_source;
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sd_event_source *sigwinch_event_source;
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struct termios saved_stdin_attr;
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struct termios saved_stdout_attr;
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bool saved_stdin:1;
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bool saved_stdout:1;
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bool stdin_readable:1;
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bool stdin_hangup:1;
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bool stdout_writable:1;
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bool stdout_hangup:1;
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bool master_readable:1;
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bool master_writable:1;
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bool master_hangup:1;
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bool read_from_master:1;
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bool done:1;
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bool drain:1;
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bool last_char_set:1;
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char last_char;
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char in_buffer[LINE_MAX], out_buffer[LINE_MAX];
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size_t in_buffer_full, out_buffer_full;
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usec_t escape_timestamp;
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unsigned escape_counter;
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PTYForwardHandler handler;
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void *userdata;
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};
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#define ESCAPE_USEC (1*USEC_PER_SEC)
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static void pty_forward_disconnect(PTYForward *f) {
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if (f) {
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f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
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f->stdout_event_source = sd_event_source_unref(f->stdout_event_source);
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f->master_event_source = sd_event_source_unref(f->master_event_source);
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f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source);
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f->event = sd_event_unref(f->event);
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if (f->saved_stdout)
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tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr);
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if (f->saved_stdin)
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tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr);
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f->saved_stdout = f->saved_stdin = false;
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}
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/* STDIN/STDOUT should not be nonblocking normally, so let's unconditionally reset it */
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(void) fd_nonblock(STDIN_FILENO, false);
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(void) fd_nonblock(STDOUT_FILENO, false);
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}
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static int pty_forward_done(PTYForward *f, int rcode) {
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_cleanup_(sd_event_unrefp) sd_event *e = NULL;
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assert(f);
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if (f->done)
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return 0;
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e = sd_event_ref(f->event);
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f->done = true;
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pty_forward_disconnect(f);
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if (f->handler)
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return f->handler(f, rcode, f->userdata);
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else
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return sd_event_exit(e, rcode < 0 ? EXIT_FAILURE : rcode);
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}
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static bool look_for_escape(PTYForward *f, const char *buffer, size_t n) {
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const char *p;
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assert(f);
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assert(buffer);
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assert(n > 0);
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for (p = buffer; p < buffer + n; p++) {
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/* Check for ^] */
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if (*p == 0x1D) {
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usec_t nw = now(CLOCK_MONOTONIC);
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if (f->escape_counter == 0 || nw > f->escape_timestamp + ESCAPE_USEC) {
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f->escape_timestamp = nw;
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f->escape_counter = 1;
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} else {
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(f->escape_counter)++;
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if (f->escape_counter >= 3)
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return true;
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}
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} else {
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f->escape_timestamp = 0;
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f->escape_counter = 0;
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}
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}
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return false;
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}
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static bool ignore_vhangup(PTYForward *f) {
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assert(f);
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if (f->flags & PTY_FORWARD_IGNORE_VHANGUP)
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return true;
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if ((f->flags & PTY_FORWARD_IGNORE_INITIAL_VHANGUP) && !f->read_from_master)
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return true;
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return false;
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}
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static bool drained(PTYForward *f) {
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int q = 0;
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assert(f);
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if (f->out_buffer_full > 0)
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return false;
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if (f->master_readable)
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return false;
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if (ioctl(f->master, TIOCINQ, &q) < 0)
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log_debug_errno(errno, "TIOCINQ failed on master: %m");
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else if (q > 0)
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return false;
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if (ioctl(f->master, TIOCOUTQ, &q) < 0)
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log_debug_errno(errno, "TIOCOUTQ failed on master: %m");
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else if (q > 0)
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return false;
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return true;
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}
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static int shovel(PTYForward *f) {
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ssize_t k;
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assert(f);
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while ((f->stdin_readable && f->in_buffer_full <= 0) ||
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(f->master_writable && f->in_buffer_full > 0) ||
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(f->master_readable && f->out_buffer_full <= 0) ||
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(f->stdout_writable && f->out_buffer_full > 0)) {
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if (f->stdin_readable && f->in_buffer_full < LINE_MAX) {
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k = read(STDIN_FILENO, f->in_buffer + f->in_buffer_full, LINE_MAX - f->in_buffer_full);
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if (k < 0) {
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if (errno == EAGAIN)
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f->stdin_readable = false;
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else if (IN_SET(errno, EIO, EPIPE, ECONNRESET)) {
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f->stdin_readable = false;
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f->stdin_hangup = true;
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f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
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} else {
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log_error_errno(errno, "read(): %m");
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return pty_forward_done(f, -errno);
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}
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} else if (k == 0) {
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/* EOF on stdin */
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f->stdin_readable = false;
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f->stdin_hangup = true;
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f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
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} else {
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/* Check if ^] has been pressed three times within one second. If we get this we quite
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* immediately. */
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if (look_for_escape(f, f->in_buffer + f->in_buffer_full, k))
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return pty_forward_done(f, -ECANCELED);
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f->in_buffer_full += (size_t) k;
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}
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}
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if (f->master_writable && f->in_buffer_full > 0) {
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k = write(f->master, f->in_buffer, f->in_buffer_full);
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if (k < 0) {
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if (IN_SET(errno, EAGAIN, EIO))
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f->master_writable = false;
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else if (IN_SET(errno, EPIPE, ECONNRESET)) {
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f->master_writable = f->master_readable = false;
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f->master_hangup = true;
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f->master_event_source = sd_event_source_unref(f->master_event_source);
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} else {
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log_error_errno(errno, "write(): %m");
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return pty_forward_done(f, -errno);
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}
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} else {
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assert(f->in_buffer_full >= (size_t) k);
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memmove(f->in_buffer, f->in_buffer + k, f->in_buffer_full - k);
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f->in_buffer_full -= k;
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}
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}
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if (f->master_readable && f->out_buffer_full < LINE_MAX) {
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k = read(f->master, f->out_buffer + f->out_buffer_full, LINE_MAX - f->out_buffer_full);
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if (k < 0) {
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/* Note that EIO on the master device
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* might be caused by vhangup() or
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* temporary closing of everything on
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* the other side, we treat it like
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* EAGAIN here and try again, unless
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* ignore_vhangup is off. */
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if (errno == EAGAIN || (errno == EIO && ignore_vhangup(f)))
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f->master_readable = false;
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else if (IN_SET(errno, EPIPE, ECONNRESET, EIO)) {
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f->master_readable = f->master_writable = false;
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f->master_hangup = true;
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f->master_event_source = sd_event_source_unref(f->master_event_source);
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} else {
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log_error_errno(errno, "read(): %m");
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return pty_forward_done(f, -errno);
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}
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} else {
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f->read_from_master = true;
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f->out_buffer_full += (size_t) k;
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}
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}
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if (f->stdout_writable && f->out_buffer_full > 0) {
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k = write(STDOUT_FILENO, f->out_buffer, f->out_buffer_full);
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if (k < 0) {
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if (errno == EAGAIN)
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f->stdout_writable = false;
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else if (IN_SET(errno, EIO, EPIPE, ECONNRESET)) {
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f->stdout_writable = false;
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f->stdout_hangup = true;
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f->stdout_event_source = sd_event_source_unref(f->stdout_event_source);
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} else {
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log_error_errno(errno, "write(): %m");
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return pty_forward_done(f, -errno);
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}
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} else {
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if (k > 0) {
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f->last_char = f->out_buffer[k-1];
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f->last_char_set = true;
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}
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assert(f->out_buffer_full >= (size_t) k);
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memmove(f->out_buffer, f->out_buffer + k, f->out_buffer_full - k);
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f->out_buffer_full -= k;
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}
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}
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}
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if (f->stdin_hangup || f->stdout_hangup || f->master_hangup) {
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/* Exit the loop if any side hung up and if there's
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* nothing more to write or nothing we could write. */
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if ((f->out_buffer_full <= 0 || f->stdout_hangup) &&
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(f->in_buffer_full <= 0 || f->master_hangup))
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return pty_forward_done(f, 0);
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}
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/* If we were asked to drain, and there's nothing more to handle from the master, then call the callback
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* too. */
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if (f->drain && drained(f))
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return pty_forward_done(f, 0);
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return 0;
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}
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static int on_master_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) {
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PTYForward *f = userdata;
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assert(f);
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assert(e);
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assert(e == f->master_event_source);
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assert(fd >= 0);
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assert(fd == f->master);
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if (revents & (EPOLLIN|EPOLLHUP))
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f->master_readable = true;
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if (revents & (EPOLLOUT|EPOLLHUP))
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f->master_writable = true;
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return shovel(f);
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}
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static int on_stdin_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) {
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PTYForward *f = userdata;
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assert(f);
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assert(e);
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assert(e == f->stdin_event_source);
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assert(fd >= 0);
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assert(fd == STDIN_FILENO);
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if (revents & (EPOLLIN|EPOLLHUP))
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f->stdin_readable = true;
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return shovel(f);
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}
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static int on_stdout_event(sd_event_source *e, int fd, uint32_t revents, void *userdata) {
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PTYForward *f = userdata;
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assert(f);
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assert(e);
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assert(e == f->stdout_event_source);
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assert(fd >= 0);
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assert(fd == STDOUT_FILENO);
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if (revents & (EPOLLOUT|EPOLLHUP))
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f->stdout_writable = true;
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return shovel(f);
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}
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static int on_sigwinch_event(sd_event_source *e, const struct signalfd_siginfo *si, void *userdata) {
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PTYForward *f = userdata;
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struct winsize ws;
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assert(f);
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assert(e);
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assert(e == f->sigwinch_event_source);
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/* The window size changed, let's forward that. */
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if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) >= 0)
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(void) ioctl(f->master, TIOCSWINSZ, &ws);
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return 0;
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}
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int pty_forward_new(
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sd_event *event,
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int master,
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PTYForwardFlags flags,
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PTYForward **ret) {
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_cleanup_(pty_forward_freep) PTYForward *f = NULL;
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struct winsize ws;
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int r;
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f = new(PTYForward, 1);
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if (!f)
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return -ENOMEM;
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*f = (struct PTYForward) {
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.flags = flags,
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.master = -1,
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};
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if (event)
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f->event = sd_event_ref(event);
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else {
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r = sd_event_default(&f->event);
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if (r < 0)
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return r;
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}
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if (!(flags & PTY_FORWARD_READ_ONLY)) {
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r = fd_nonblock(STDIN_FILENO, true);
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if (r < 0)
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return r;
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r = fd_nonblock(STDOUT_FILENO, true);
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if (r < 0)
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return r;
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}
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r = fd_nonblock(master, true);
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if (r < 0)
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return r;
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f->master = master;
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if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) < 0) {
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/* If we can't get the resolution from the output fd, then use our internal, regular width/height,
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* i.e. something derived from $COLUMNS and $LINES if set. */
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ws = (struct winsize) {
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.ws_row = lines(),
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.ws_col = columns(),
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};
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}
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(void) ioctl(master, TIOCSWINSZ, &ws);
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if (!(flags & PTY_FORWARD_READ_ONLY)) {
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if (tcgetattr(STDIN_FILENO, &f->saved_stdin_attr) >= 0) {
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struct termios raw_stdin_attr;
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f->saved_stdin = true;
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raw_stdin_attr = f->saved_stdin_attr;
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cfmakeraw(&raw_stdin_attr);
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raw_stdin_attr.c_oflag = f->saved_stdin_attr.c_oflag;
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tcsetattr(STDIN_FILENO, TCSANOW, &raw_stdin_attr);
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}
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if (tcgetattr(STDOUT_FILENO, &f->saved_stdout_attr) >= 0) {
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struct termios raw_stdout_attr;
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f->saved_stdout = true;
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raw_stdout_attr = f->saved_stdout_attr;
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cfmakeraw(&raw_stdout_attr);
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raw_stdout_attr.c_iflag = f->saved_stdout_attr.c_iflag;
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raw_stdout_attr.c_lflag = f->saved_stdout_attr.c_lflag;
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tcsetattr(STDOUT_FILENO, TCSANOW, &raw_stdout_attr);
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}
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r = sd_event_add_io(f->event, &f->stdin_event_source, STDIN_FILENO, EPOLLIN|EPOLLET, on_stdin_event, f);
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if (r < 0 && r != -EPERM)
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return r;
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if (r >= 0)
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(void) sd_event_source_set_description(f->stdin_event_source, "ptyfwd-stdin");
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}
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r = sd_event_add_io(f->event, &f->stdout_event_source, STDOUT_FILENO, EPOLLOUT|EPOLLET, on_stdout_event, f);
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if (r == -EPERM)
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/* stdout without epoll support. Likely redirected to regular file. */
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f->stdout_writable = true;
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else if (r < 0)
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return r;
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else
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(void) sd_event_source_set_description(f->stdout_event_source, "ptyfwd-stdout");
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r = sd_event_add_io(f->event, &f->master_event_source, master, EPOLLIN|EPOLLOUT|EPOLLET, on_master_event, f);
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if (r < 0)
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return r;
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(void) sd_event_source_set_description(f->master_event_source, "ptyfwd-master");
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r = sd_event_add_signal(f->event, &f->sigwinch_event_source, SIGWINCH, on_sigwinch_event, f);
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if (r < 0)
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return r;
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(void) sd_event_source_set_description(f->sigwinch_event_source, "ptyfwd-sigwinch");
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*ret = TAKE_PTR(f);
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return 0;
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}
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PTYForward *pty_forward_free(PTYForward *f) {
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pty_forward_disconnect(f);
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return mfree(f);
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}
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int pty_forward_get_last_char(PTYForward *f, char *ch) {
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assert(f);
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assert(ch);
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if (!f->last_char_set)
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return -ENXIO;
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*ch = f->last_char;
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return 0;
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}
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int pty_forward_set_ignore_vhangup(PTYForward *f, bool b) {
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int r;
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assert(f);
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if (!!(f->flags & PTY_FORWARD_IGNORE_VHANGUP) == b)
|
|
return 0;
|
|
|
|
SET_FLAG(f->flags, PTY_FORWARD_IGNORE_VHANGUP, b);
|
|
|
|
if (!ignore_vhangup(f)) {
|
|
|
|
/* We shall now react to vhangup()s? Let's check
|
|
* immediately if we might be in one */
|
|
|
|
f->master_readable = true;
|
|
r = shovel(f);
|
|
if (r < 0)
|
|
return r;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
bool pty_forward_get_ignore_vhangup(PTYForward *f) {
|
|
assert(f);
|
|
|
|
return !!(f->flags & PTY_FORWARD_IGNORE_VHANGUP);
|
|
}
|
|
|
|
bool pty_forward_is_done(PTYForward *f) {
|
|
assert(f);
|
|
|
|
return f->done;
|
|
}
|
|
|
|
void pty_forward_set_handler(PTYForward *f, PTYForwardHandler cb, void *userdata) {
|
|
assert(f);
|
|
|
|
f->handler = cb;
|
|
f->userdata = userdata;
|
|
}
|
|
|
|
bool pty_forward_drain(PTYForward *f) {
|
|
assert(f);
|
|
|
|
/* Starts draining the forwarder. Specifically:
|
|
*
|
|
* - Returns true if there are no unprocessed bytes from the pty, false otherwise
|
|
*
|
|
* - Makes sure the handler function is called the next time the number of unprocessed bytes hits zero
|
|
*/
|
|
|
|
f->drain = true;
|
|
return drained(f);
|
|
}
|
|
|
|
int pty_forward_set_priority(PTYForward *f, int64_t priority) {
|
|
int r;
|
|
assert(f);
|
|
|
|
r = sd_event_source_set_priority(f->stdin_event_source, priority);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_event_source_set_priority(f->stdout_event_source, priority);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_event_source_set_priority(f->master_event_source, priority);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
r = sd_event_source_set_priority(f->sigwinch_event_source, priority);
|
|
if (r < 0)
|
|
return r;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int pty_forward_set_width_height(PTYForward *f, unsigned width, unsigned height) {
|
|
struct winsize ws;
|
|
|
|
assert(f);
|
|
|
|
if (width == (unsigned) -1 && height == (unsigned) -1)
|
|
return 0; /* noop */
|
|
|
|
if (width != (unsigned) -1 &&
|
|
(width == 0 || width > USHRT_MAX))
|
|
return -ERANGE;
|
|
|
|
if (height != (unsigned) -1 &&
|
|
(height == 0 || height > USHRT_MAX))
|
|
return -ERANGE;
|
|
|
|
if (width == (unsigned) -1 || height == (unsigned) -1) {
|
|
if (ioctl(f->master, TIOCGWINSZ, &ws) < 0)
|
|
return -errno;
|
|
|
|
if (width != (unsigned) -1)
|
|
ws.ws_col = width;
|
|
if (height != (unsigned) -1)
|
|
ws.ws_row = height;
|
|
} else
|
|
ws = (struct winsize) {
|
|
.ws_row = height,
|
|
.ws_col = width,
|
|
};
|
|
|
|
if (ioctl(f->master, TIOCSWINSZ, &ws) < 0)
|
|
return -errno;
|
|
|
|
/* Make sure we ignore SIGWINCH window size events from now on */
|
|
f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source);
|
|
|
|
return 0;
|
|
}
|