1 /* 2 * resizewin 3 * 4 * Query terminal for size and inform the kernel 5 * 6 * Copyright 2015 EMC / Isilon Storage Division 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 #include <sys/ioctl.h> 33 #include <sys/time.h> 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <strings.h> 39 #include <termios.h> 40 #include <unistd.h> 41 42 /* screen doesn't support ESC[18t (return terminal size) so do it the hard way */ 43 static const char query[] = 44 "\0337" /* Save cursor position */ 45 "\033[r" /* Scroll whole screen */ 46 "\033[999;999H" /* Move cursor */ 47 "\033[6n" /* Get cursor position */ 48 "\0338"; /* Restore cursor position */ 49 int 50 main(__unused int argc, __unused char **argv) 51 { 52 struct termios old, new; 53 struct winsize w; 54 int ret, fd, cnt, err; 55 char data[20]; 56 struct timeval then, now; 57 58 err = 0; 59 60 if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1) 61 exit(1); 62 63 /* Disable echo */ 64 if (tcgetattr(fd, &old) == -1) 65 exit(1); 66 67 new = old; 68 new.c_cflag |= (CLOCAL | CREAD); 69 new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); 70 if (tcsetattr(fd, TCSANOW, &new) == -1) 71 exit(1); 72 73 if (write(fd, query, sizeof(query)) != sizeof(query)) { 74 err = 1; 75 goto out; 76 } 77 78 /* Read the response */ 79 bzero(data, sizeof(data)); 80 gettimeofday(&then, NULL); 81 cnt = 0; 82 while (1) { 83 ret = read(fd, data + cnt, 1); 84 85 if (ret == -1) { 86 if (errno == EAGAIN) { 87 gettimeofday(&now, NULL); 88 timersub(&now, &then, &now); 89 if (now.tv_sec >= 2) { 90 fprintf(stderr, "\n\n\nTimeout reading from terminal\n"); 91 fprintf(stderr, "Read %d bytes, %s\n", cnt, data); 92 err = 1; 93 goto out; 94 } 95 96 usleep(20000); 97 continue; 98 } 99 err = 1; 100 goto out; 101 } 102 if (data[cnt] == 'R') 103 break; 104 105 cnt++; 106 if (cnt == sizeof(data) - 2) { 107 fprintf(stderr, "Response too long\n"); 108 err = 1; 109 goto out; 110 } 111 } 112 113 /* Parse */ 114 if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) { 115 err = 1; 116 fprintf(stderr, "Unable to parse response\n"); 117 goto out; 118 } 119 120 /* Finally, what we want */ 121 if (ioctl(fd, TIOCSWINSZ, &w) == -1) 122 err = 1; 123 out: 124 /* Restore echo */ 125 tcsetattr(fd, TCSANOW, &old); 126 127 close(fd); 128 exit(err); 129 } 130