Track window size changes that happen while sudo is suspended

diff --git a/src/exec_pty.c b/src/exec_pty.c
index 58d2a249dd8d2aef8cc12a6d42267bdd2df0d2b5..bd0be1e99099f4c2bdc55c917370027928f02471 100644 (file)
--- a/src/exec_pty.c
+++ b/src/exec_pty.c
@@ -415,11 +415,14 @@ check_foreground(pid_t ppgrp)
     debug_decl(check_foreground, SUDO_DEBUG_EXEC);
 
     if (io_fds[SFD_USERTTY] != -1) {
+       /* Always check for window size changes. */
+       sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
+
        foreground = tcgetpgrp(io_fds[SFD_USERTTY]) == ppgrp;
-       if (foreground && !tty_initialized) {
-           if (sudo_term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE])) {
-               sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
-               tty_initialized = true;
+       if (foreground) {
+           if (!tty_initialized) {
+               if (sudo_term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]))
+                   tty_initialized = true;
            }
        }
     }
@@ -1372,12 +1375,13 @@ exec_pty(struct command_details *details, struct command_status *cstat)
        }
     }
 
+    /* Set pty window size. */
+    sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
+
     if (foreground) {
        /* Copy terminal attrs from user tty -> pty slave. */
-       if (sudo_term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE])) {
-           sync_ttysize(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]);
+       if (sudo_term_copy(io_fds[SFD_USERTTY], io_fds[SFD_SLAVE]))
            tty_initialized = true;
-       }
 
        /* Start out in raw mode unless part of a pipeline or backgrounded. */
        if (!pipeline && !ISSET(details->flags, CD_EXEC_BG)) {
@@ -1631,17 +1635,25 @@ del_io_events(bool nonblocking)
 static void
 sync_ttysize(int src, int dst)
 {
-    struct winsize wsize;
+    struct winsize wsize, owsize;
     pid_t pgrp;
     debug_decl(sync_ttysize, SUDO_DEBUG_EXEC);
 
-    if (ioctl(src, TIOCGWINSZ, &wsize) == 0) {
-           (void)ioctl(dst, TIOCSWINSZ, &wsize);
-           if ((pgrp = tcgetpgrp(dst)) != -1)
-               killpg(pgrp, SIGWINCH);
+    if (ioctl(src, TIOCGWINSZ, &wsize) == 0 &&
+       ioctl(dst, TIOCGWINSZ, &owsize) == 0 &&
+       (wsize.ws_row != owsize.ws_row || wsize.ws_col != owsize.ws_col)) {
+
+       sudo_debug_printf(SUDO_DEBUG_INFO,
+           "window size change %dx%d -> %dx%d",
+           owsize.ws_col, owsize.ws_row, wsize.ws_col, wsize.ws_row);
+
+       (void)ioctl(dst, TIOCSWINSZ, &wsize);
+       if ((pgrp = tcgetpgrp(dst)) != -1)
+           killpg(pgrp, SIGWINCH);
 
-           if (tty_initialized)
-               log_winchange(wsize.ws_row, wsize.ws_col);
+       /* Only log window size changes, not the initial setting. */
+       if (tty_initialized)
+           log_winchange(wsize.ws_row, wsize.ws_col);
     }
 
     debug_return;