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 <err.h> 35 #include <errno.h> 36 #include <fcntl.h> 37 #include <stdio.h> 38 #include <stdlib.h> 39 #include <strings.h> 40 #include <termios.h> 41 #include <unistd.h> 42 43 /* screen doesn't support ESC[18t (return terminal size) so do it the hard way */ 44 static const char query[] = 45 "\0337" /* Save cursor position */ 46 "\033[r" /* Scroll whole screen */ 47 "\033[999;999H" /* Move cursor */ 48 "\033[6n" /* Get cursor position */ 49 "\0338"; /* Restore cursor position */ 50 51 static void 52 usage(void) 53 { 54 55 fprintf(stderr, "usage: resizewin [-z]\n"); 56 exit(1); 57 } 58 59 int 60 main(int argc, char **argv) 61 { 62 struct termios old, new; 63 struct winsize w; 64 struct timeval then, now; 65 char data[20]; 66 int ch, cnt, error, fd, ret, zflag; 67 68 error = 0; 69 zflag = 0; 70 while ((ch = getopt(argc, argv, "z")) != -1) { 71 switch (ch) { 72 case 'z': 73 zflag = 1; 74 break; 75 case '?': 76 default: 77 usage(); 78 } 79 } 80 argc -= optind; 81 if (argc != 0) 82 usage(); 83 84 if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1) 85 exit(1); 86 87 if (zflag) { 88 if (ioctl(fd, TIOCGWINSZ, &w) == -1) 89 exit(1); 90 if (w.ws_row != 0 && w.ws_col != 0) 91 exit(0); 92 } 93 94 /* Disable echo */ 95 if (tcgetattr(fd, &old) == -1) 96 exit(1); 97 98 new = old; 99 new.c_cflag |= (CLOCAL | CREAD); 100 new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG); 101 if (tcsetattr(fd, TCSANOW, &new) == -1) 102 exit(1); 103 104 /* Discard input received so far */ 105 error = tcflush(fd, TCIOFLUSH); 106 if (error != 0) 107 warn("tcflush"); 108 109 if (write(fd, query, sizeof(query)) != sizeof(query)) { 110 error = 1; 111 goto out; 112 } 113 114 /* Read the response */ 115 bzero(data, sizeof(data)); 116 gettimeofday(&then, NULL); 117 cnt = 0; 118 while (1) { 119 ret = read(fd, data + cnt, 1); 120 121 if (ret == -1) { 122 if (errno == EAGAIN) { 123 gettimeofday(&now, NULL); 124 timersub(&now, &then, &now); 125 if (now.tv_sec >= 2) { 126 warnx("timeout reading from terminal"); 127 error = 1; 128 goto out; 129 } 130 131 usleep(20000); 132 continue; 133 } 134 error = 1; 135 goto out; 136 } 137 if (data[cnt] == 'R') 138 break; 139 140 cnt++; 141 if (cnt == sizeof(data) - 2) { 142 warnx("response too long"); 143 error = 1; 144 goto out; 145 } 146 } 147 148 /* Parse */ 149 if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) { 150 error = 1; 151 warnx("unable to parse response"); 152 goto out; 153 } 154 155 /* Finally, what we want */ 156 if (ioctl(fd, TIOCSWINSZ, &w) == -1) 157 error = 1; 158 out: 159 /* Restore echo */ 160 tcsetattr(fd, TCSANOW, &old); 161 162 close(fd); 163 exit(error); 164 } 165