Break up io_callback() into read_callback() and write_callback()
to make it clear that we can't get an event with both read and write set.
This commit is contained in:
Todd C. Miller
223
src/exec_pty.c
223
src/exec_pty.c
@@ -537,130 +537,137 @@ terminate_command(pid_t pid, bool use_pgrp)
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}
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/*
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* Read/write an iobuf that is ready.
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* Read an iobuf that is ready.
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*/
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static void
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io_callback(int fd, int what, void *v)
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read_callback(int fd, int what, void *v)
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{
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struct io_buffer *iob = v;
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struct sudo_event_base *evbase;
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int n;
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debug_decl(io_callback, SUDO_DEBUG_EXEC);
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debug_decl(read_callback, SUDO_DEBUG_EXEC);
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if (ISSET(what, SUDO_EV_WRITE)) {
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evbase = sudo_ev_get_base(iob->wevent);
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do {
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n = write(fd, iob->buf + iob->off, iob->len - iob->off);
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} while (n == -1 && errno == EINTR);
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if (n == -1) {
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switch (errno) {
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case EPIPE:
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case ENXIO:
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case EIO:
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case EBADF:
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/* other end of pipe closed or pty revoked */
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evbase = sudo_ev_get_base(iob->revent);
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do {
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n = read(fd, iob->buf + iob->len, sizeof(iob->buf) - iob->len);
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} while (n == -1 && errno == EINTR);
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switch (n) {
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case -1:
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if (errno == EAGAIN)
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break;
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/* treat read error as fatal and close the fd */
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"error reading fd %d: %s", fd, strerror(errno));
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/* FALLTHROUGH */
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case 0:
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/* got EOF or pty has gone away */
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if (n == 0) {
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"unable to write %d bytes to fd %d",
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iob->len - iob->off, fd);
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/* Close reader if there is one. */
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if (iob->revent != NULL) {
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safe_close(sudo_ev_get_fd(iob->revent));
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ev_free_by_fd(evbase, sudo_ev_get_fd(iob->revent));
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}
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CLR(what, SUDO_EV_READ);
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safe_close(fd);
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ev_free_by_fd(evbase, fd);
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break;
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case EAGAIN:
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/* not an error */
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break;
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default:
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#if 0 /* XXX -- how to set cstat? stash in iobufs instead? */
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if (cstat != NULL) {
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cstat->type = CMD_ERRNO;
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cstat->val = errno;
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}
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#endif /* XXX */
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"error writing fd %d: %s", fd, strerror(errno));
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sudo_ev_loopbreak(evbase);
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break;
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"read EOF from fd %d", fd);
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}
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} else {
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"wrote %d bytes to fd %d", n, fd);
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iob->off += n;
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/* Reset buffer if fully consumed. */
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if (iob->off == iob->len) {
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safe_close(fd);
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ev_free_by_fd(evbase, fd);
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/* If writer already consumed the buffer, close it too. */
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if (iob->wevent != NULL && iob->off == iob->len) {
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safe_close(sudo_ev_get_fd(iob->wevent));
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ev_free_by_fd(evbase, sudo_ev_get_fd(iob->wevent));
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iob->off = iob->len = 0;
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/* Forward the EOF from reader to writer. */
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if (iob->revent == NULL) {
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CLR(what, SUDO_EV_READ);
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safe_close(fd);
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ev_free_by_fd(evbase, fd);
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}
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}
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/* Re-enable writer if buffer is not empty. */
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if (iob->len > iob->off) {
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break;
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default:
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"read %d bytes from fd %d", n, fd);
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if (!iob->action(iob->buf + iob->len, n, iob))
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terminate_command(cmnd_pid, true);
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iob->len += n;
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/* Enable writer if not /dev/tty or we are foreground pgrp. */
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if (iob->wevent != NULL &&
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(foreground || !USERTTY_EVENT(iob->wevent))) {
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if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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/* Enable reader if buffer is not full. */
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if (iob->revent != NULL &&
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(ttymode == TERM_RAW || !USERTTY_EVENT(iob->revent))) {
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if (iob->len != sizeof(iob->buf)) {
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if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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/* Re-enable reader if buffer is not full. */
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if (iob->len != sizeof(iob->buf)) {
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if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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}
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break;
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}
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if (ISSET(what, SUDO_EV_READ)) {
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evbase = sudo_ev_get_base(iob->revent);
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do {
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n = read(fd, iob->buf + iob->len, sizeof(iob->buf) - iob->len);
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} while (n == -1 && errno == EINTR);
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switch (n) {
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case -1:
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if (errno == EAGAIN)
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break;
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/* treat read error as fatal and close the fd */
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"error reading fd %d: %s", fd, strerror(errno));
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/* FALLTHROUGH */
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case 0:
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/* got EOF or pty has gone away */
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if (n == 0) {
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"read EOF from fd %d", fd);
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}
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}
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/*
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* Write an iobuf that is ready.
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*/
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static void
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write_callback(int fd, int what, void *v)
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{
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struct io_buffer *iob = v;
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struct sudo_event_base *evbase;
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int n;
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debug_decl(write_callback, SUDO_DEBUG_EXEC);
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evbase = sudo_ev_get_base(iob->wevent);
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do {
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n = write(fd, iob->buf + iob->off, iob->len - iob->off);
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} while (n == -1 && errno == EINTR);
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if (n == -1) {
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switch (errno) {
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case EPIPE:
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case ENXIO:
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case EIO:
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case EBADF:
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/* other end of pipe closed or pty revoked */
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"unable to write %d bytes to fd %d",
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iob->len - iob->off, fd);
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/* Close reader if there is one. */
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if (iob->revent != NULL) {
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safe_close(sudo_ev_get_fd(iob->revent));
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ev_free_by_fd(evbase, sudo_ev_get_fd(iob->revent));
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}
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safe_close(fd);
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ev_free_by_fd(evbase, fd);
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break;
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case EAGAIN:
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/* not an error */
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break;
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default:
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#if 0 /* XXX -- how to set cstat? stash in iobufs instead? */
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if (cstat != NULL) {
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cstat->type = CMD_ERRNO;
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cstat->val = errno;
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}
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#endif /* XXX */
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"error writing fd %d: %s", fd, strerror(errno));
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sudo_ev_loopbreak(evbase);
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break;
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}
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} else {
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"wrote %d bytes to fd %d", n, fd);
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iob->off += n;
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/* Reset buffer if fully consumed. */
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if (iob->off == iob->len) {
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iob->off = iob->len = 0;
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/* Forward the EOF from reader to writer. */
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if (iob->revent == NULL) {
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safe_close(fd);
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ev_free_by_fd(evbase, fd);
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/* If writer already consumed the buffer, close it too. */
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if (iob->wevent != NULL && iob->off == iob->len) {
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safe_close(sudo_ev_get_fd(iob->wevent));
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ev_free_by_fd(evbase, sudo_ev_get_fd(iob->wevent));
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iob->off = iob->len = 0;
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}
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break;
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default:
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sudo_debug_printf(SUDO_DEBUG_INFO,
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"read %d bytes from fd %d", n, fd);
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if (!iob->action(iob->buf + iob->len, n, iob))
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terminate_command(cmnd_pid, true);
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iob->len += n;
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/* Enable writer if not /dev/tty or we are foreground pgrp. */
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if (iob->wevent != NULL &&
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(foreground || !USERTTY_EVENT(iob->wevent))) {
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if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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/* Re-enable reader if buffer is not full. */
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if (iob->len != sizeof(iob->buf)) {
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if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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break;
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}
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}
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/* Re-enable writer if buffer is not empty. */
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if (iob->len > iob->off) {
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if (sudo_ev_add(evbase, iob->wevent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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/* Enable reader if buffer is not full. */
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if (iob->revent != NULL &&
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(ttymode == TERM_RAW || !USERTTY_EVENT(iob->revent))) {
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if (iob->len != sizeof(iob->buf)) {
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if (sudo_ev_add(evbase, iob->revent, NULL, false) == -1)
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sudo_fatal(U_("unable to add event to queue"));
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}
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}
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}
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}
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@@ -684,8 +691,8 @@ io_buf_new(int rfd, int wfd, bool (*action)(const char *, unsigned int, struct i
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/* Allocate and add to head of list. */
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if ((iob = malloc(sizeof(*iob))) == NULL)
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sudo_fatalx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
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iob->revent = sudo_ev_alloc(rfd, SUDO_EV_READ, io_callback, iob);
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iob->wevent = sudo_ev_alloc(wfd, SUDO_EV_WRITE, io_callback, iob);
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iob->revent = sudo_ev_alloc(rfd, SUDO_EV_READ, read_callback, iob);
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iob->wevent = sudo_ev_alloc(wfd, SUDO_EV_WRITE, write_callback, iob);
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iob->len = 0;
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iob->off = 0;
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iob->action = action;
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