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 #include <sys/ioctl.h> 32 #include <sys/time.h> 33 #include <err.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 50 static void 51 usage(void) 52 { 53 54 fprintf(stderr, "usage: resizewin [-z]\n"); 55 exit(1); 56 } 57 58 int 59 main(int argc, char **argv) 60 { 61 struct termios old, new; 62 struct winsize w; 63 struct timeval then, now; 64 char data[20]; 65 int ch, cnt, error, fd, ret, zflag; 66 67 error = 0; 68 zflag = 0; 69 while ((ch = getopt(argc, argv, "z")) != -1) { 70 switch (ch) { 71 case 'z': 72 zflag = 1; 73 break; 74 case '?': 75 default: 76 usage(); 77 } 78 } 79 argc -= optind; 80 if (argc != 0) 81 usage(); 82 83 if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1) 84 exit(1); 85 86 if (zflag) { 87 if (ioctl(fd, TIOCGWINSZ, &w) == -1) 88 exit(1); 89 if (w.ws_row != 0 && w.ws_col != 0) 90 exit(0); 91 } 92 93 /* Disable echo, flush the input, and drain the output */ 94 if (tcgetattr(fd, &old) == -1) 95 exit(1); 96 97 new = old; 98 new.c_cflag |= (CLOCAL | CREAD); 99 new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); 100 if (tcsetattr(fd, TCSAFLUSH, &new) == -1) 101 exit(1); 102 103 if (write(fd, query, sizeof(query) - 1) != sizeof(query) - 1) { 104 error = 1; 105 goto out; 106 } 107 108 /* Read the response */ 109 bzero(data, sizeof(data)); 110 gettimeofday(&then, NULL); 111 cnt = 0; 112 while (1) { 113 ret = read(fd, data + cnt, 1); 114 115 if (ret == -1) { 116 if (errno == EAGAIN) { 117 gettimeofday(&now, NULL); 118 timersub(&now, &then, &now); 119 if (now.tv_sec >= 2) { 120 warnx("timeout reading from terminal"); 121 error = 1; 122 goto out; 123 } 124 125 usleep(20000); 126 continue; 127 } 128 error = 1; 129 goto out; 130 } 131 if (data[cnt] == 'R') 132 break; 133 134 cnt++; 135 if (cnt == sizeof(data) - 2) { 136 warnx("response too long"); 137 error = 1; 138 goto out; 139 } 140 } 141 142 /* Parse */ 143 if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) { 144 error = 1; 145 warnx("unable to parse response"); 146 goto out; 147 } 148 149 /* Finally, what we want */ 150 if (ioctl(fd, TIOCSWINSZ, &w) == -1) 151 error = 1; 152 out: 153 /* Restore echo */ 154 tcsetattr(fd, TCSANOW, &old); 155 156 close(fd); 157 exit(error); 158 } 159