setterm: add --resize option

Reset terminal size by assessing maximum row and column.  This is useful
when actual geometry and kernel terminal driver are not in sync.

Addresses: http://bugs.debian.org/835636
Based-on-work-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Sami Kerola <kerolasa@iki.fi>

diff --git a/term-utils/setterm.1 b/term-utils/setterm.1
index 2a06c1a0858d6b800814e93a791f8cd9f7d1aba8..22a8ff03a58dbc119b79938da985dfe27d09f3e9 100644 (file)
--- a/term-utils/setterm.1
+++ b/term-utils/setterm.1
@@ -228,6 +228,13 @@ Turns keyboard repeat on or off.
 Displays the terminal reset string, which typically resets the terminal to
 its power-on state.
 .TP
+\fB\-\-resize\fP
+Reset terminal size by assessing maximum row and column.  This is useful
+when actual geometry and kernel terminal driver are not in sync.  Most
+notable use case is with serial consoles, that do not use
+.BR ioctl (3)
+but just byte streams and breaks.
+.TP
 \fB\-\-reverse\fP [\fBon\fP|\fBoff\fP]
 Turns reverse video mode on or off.  Except on a virtual console,
 .B \-\-reverse off

diff --git a/term-utils/setterm.c b/term-utils/setterm.c
index abcf8b2916a287ad025c71676e63bb3781f4f503..900a9f3b1b60dd3dd5b8de6f16dd75edf13f7768 100644 (file)
--- a/term-utils/setterm.c
+++ b/term-utils/setterm.c
@@ -75,6 +75,7 @@
 # include <linux/tiocl.h>
 #endif
 
+#include "all-io.h"
 #include "c.h"
 #include "closestream.h"
 #include "nls.h"
@@ -182,7 +183,7 @@ struct setterm_control {
            opt_appck_on:1, opt_invsc_on:1, opt_msg_on:1, opt_cl_all:1,
            vcterm:1;
        /* Option flags.  Set when an option is invoked. */
-       uint64_t opt_term:1, opt_reset:1, opt_initialize:1, opt_cursor:1,
+       uint64_t opt_term:1, opt_reset:1, opt_resize:1, opt_initialize:1, opt_cursor:1,
            opt_linewrap:1, opt_default:1, opt_foreground:1,
            opt_background:1, opt_bold:1, opt_blink:1, opt_reverse:1,
            opt_underline:1, opt_store:1, opt_clear:1, opt_blank:1,
@@ -385,6 +386,7 @@ static void __attribute__((__noreturn__)) usage(FILE *out)
        fputs(USAGE_OPTIONS, out);
        fputs(_(" --term          <terminal_name>   override TERM environment variable\n"), out);
        fputs(_(" --reset                           reset terminal to power-on state\n"), out);
+       fputs(_(" --resize                          reset terminal rows and columns\n"), out);
        fputs(_(" --initialize                      display init string, and use default settings\n"), out);
        fputs(_(" --default                         use default terminal settings\n"), out);
        fputs(_(" --store                           save current terminal settings as default\n"), out);
@@ -437,6 +439,7 @@ static void parse_option(struct setterm_control *ctl, int ac, char **av)
        enum {
                OPT_TERM = CHAR_MAX + 1,
                OPT_RESET,
+               OPT_RESIZE,
                OPT_INITIALIZE,
                OPT_CURSOR,
                OPT_REPEAT,
@@ -474,6 +477,7 @@ static void parse_option(struct setterm_control *ctl, int ac, char **av)
        static const struct option longopts[] = {
                {"term", required_argument, NULL, OPT_TERM},
                {"reset", no_argument, NULL, OPT_RESET},
+               {"resize", no_argument, NULL, OPT_RESIZE},
                {"initialize", no_argument, NULL, OPT_INITIALIZE},
                {"cursor", required_argument, NULL, OPT_CURSOR},
                {"repeat", required_argument, NULL, OPT_REPEAT},
@@ -527,6 +531,9 @@ static void parse_option(struct setterm_control *ctl, int ac, char **av)
                case OPT_RESET:
                        ctl->opt_reset = set_opt_flag(ctl->opt_reset);
                        break;
+               case OPT_RESIZE:
+                       ctl->opt_resize = set_opt_flag(ctl->opt_resize);
+                       break;
                case OPT_INITIALIZE:
                        ctl->opt_initialize = set_opt_flag(ctl->opt_initialize);
                        break;
@@ -815,6 +822,104 @@ static int vc_only(struct setterm_control *ctl, const char *err)
        return ctl->vcterm;
 }
 
+static void tty_raw(struct termios *saved_attributes, int *saved_fl)
+{
+       struct termios tattr;
+
+       fcntl(STDIN_FILENO, F_GETFL, saved_fl);
+       tcgetattr(STDIN_FILENO, saved_attributes);
+       fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK);
+       memcpy(&tattr, saved_attributes, sizeof(struct termios));
+       tattr.c_lflag &= ~(ICANON | ECHO);
+       tattr.c_cc[VMIN] = 1;
+       tattr.c_cc[VTIME] = 0;
+       tcsetattr(STDIN_FILENO, TCSAFLUSH, &tattr);
+}
+
+static void tty_restore(struct termios *saved_attributes, int *saved_fl)
+{
+       fcntl(STDIN_FILENO, F_SETFL, *saved_fl);
+       tcsetattr(STDIN_FILENO, TCSANOW, saved_attributes);
+}
+
+static int select_wait(void)
+{
+       struct timeval tv;
+       fd_set set;
+       int ret;
+
+       FD_ZERO(&set);
+       FD_SET(STDIN_FILENO, &set);
+       tv.tv_sec = 10;
+       tv.tv_usec = 0;
+       while ((ret = select(1, &set, NULL, NULL, &tv)) < 0) {
+               if (errno == EINTR)
+                       continue;
+               err(EXIT_FAILURE, _("select failed"));
+       }
+       return ret;
+}
+
+static int resizetty(void)
+{
+       /* 
+        * \e7        Save current state (cursor coordinates, attributes,
+        *                character sets pointed at by G0, G1).
+        * \e[r       Set scrolling region; parameters are top and bottom row.
+        * \e[32766E  Move cursor down 32766 (INT16_MAX - 1) rows.
+        * \e[32766C  Move cursor right 32766 columns.
+        * \e[6n      Report cursor position.
+        * \e8        Restore state most recently saved by \e7.
+        */
+       static const char *getpos = "\e7\e[r\e[32766E\e[32766C\e[6n\e8";
+       char retstr[32];
+       int row, col;
+       size_t pos;
+       ssize_t rc;
+       struct winsize ws;
+       struct termios saved_attributes;
+       int saved_fl;
+
+       if (!isatty(STDIN_FILENO))
+               errx(EXIT_FAILURE, _("stdin does not refer to a terminal"));
+
+       tty_raw(&saved_attributes, &saved_fl);
+       if (write_all(STDIN_FILENO, getpos, strlen(getpos)) < 0) {
+               warn(_("write failed"));
+               tty_restore(&saved_attributes, &saved_fl);
+               return 1;
+       }
+       for (pos = 0; pos < sizeof(retstr) - 1;) {
+               if (0 == select_wait())
+                       break;
+               if ((rc =
+                    read(STDIN_FILENO, retstr + pos,
+                         sizeof(retstr) - 1 - pos)) < 0) {
+                       if (errno == EINTR)
+                               continue;
+                       warn(_("read failed"));
+                       tty_restore(&saved_attributes, &saved_fl);
+                       return 1;
+               }
+               pos += rc;
+               if (retstr[pos - 1] == 'R')
+                       break;
+       }
+       retstr[pos] = 0;
+       tty_restore(&saved_attributes, &saved_fl);
+       rc = sscanf(retstr, "\033[%d;%dR", &row, &col);
+       if (rc != 2) {
+               warnx(_("invalid cursor position: %s"), retstr);
+               return 1;
+       }
+       memset(&ws, 0, sizeof(struct winsize));
+       ioctl(STDIN_FILENO, TIOCGWINSZ, &ws);
+       ws.ws_row = row;
+       ws.ws_col = col;
+       ioctl(STDIN_FILENO, TIOCSWINSZ, &ws);
+       return 0;
+}
+
 static void perform_sequence(struct setterm_control *ctl)
 {
        int result;
@@ -823,6 +928,11 @@ static void perform_sequence(struct setterm_control *ctl)
        if (ctl->opt_reset)
                putp(ti_entry("rs1"));
 
+       /* -resize. */
+       if (ctl->opt_resize)
+               if (resizetty())
+                       warnx(_("reset failed"));
+
        /* -initialize. */
        if (ctl->opt_initialize)
                putp(ti_entry("is2"));