lib/ttyutils.c

   1 /*
   2  * No copyright is claimed.  This code is in the public domain; do with
   3  * it what you wish.
   4  *
   5  * Written by Karel Zak <kzak@redhat.com>
   6  */
   7 #include <ctype.h>
   8 #include <unistd.h>
   9
  10 #include "c.h"
  11 #include "ttyutils.h"
  12
  13 int get_terminal_width(int default_width)
  14 {
  15         int width = 0;
  16
  17 #if defined(TIOCGWINSZ)
  18         struct winsize  w_win;
  19         if (ioctl (STDOUT_FILENO, TIOCGWINSZ, &w_win) == 0)
  20                 width = w_win.ws_col;
  21 #elif defined(TIOCGSIZE)
  22         struct ttysize  t_win;
  23         if (ioctl (STDOUT_FILENO, TIOCGSIZE, &t_win) == 0)
  24                 width = t_win.ts_cols;
  25 #endif
  26
  27         if (width <= 0) {
  28                 const char *cp = getenv("COLUMNS");
  29
  30                 if (cp) {
  31                         char *end = NULL;
  32                         long c;
  33
  34                         errno = 0;
  35                         c = strtol(cp, &end, 10);
  36
  37                         if (errno == 0 && end && *end == '\0' && end > cp &&
  38                             c > 0 && c <= INT_MAX)
  39                                 width = c;
  40                 }
  41         }
  42
  43         return width > 0 ? width : default_width;
  44 }
  45
  46 int get_terminal_name(const char **path,
  47                       const char **name,
  48                       const char **number)
  49 {
  50         const char *tty;
  51         const char *p;
  52         int fd;
  53
  54
  55         if (name)
  56                 *name = NULL;
  57         if (path)
  58                 *path = NULL;
  59         if (number)
  60                 *number = NULL;
  61
  62         if (isatty(STDIN_FILENO))
  63                 fd = STDIN_FILENO;
  64         else if (isatty(STDOUT_FILENO))
  65                 fd = STDOUT_FILENO;
  66         else if (isatty(STDERR_FILENO))
  67                 fd = STDERR_FILENO;
  68         else
  69                 return -1;
  70
  71         tty = ttyname(fd);
  72         if (!tty)
  73                 return -1;
  74         if (path)
  75                 *path = tty;
  76         tty = strncmp(tty, "/dev/", 5) == 0 ? tty + 5 : tty;
  77         if (name)
  78                 *name = tty;
  79         if (number) {
  80                 for (p = tty; p && *p; p++) {
  81                         if (isdigit(*p)) {
  82                                 *number = p;
  83                                 break;
  84                         }
  85                 }
  86         }
  87         return 0;
  88 }
  89
  90
  91 #ifdef TEST_PROGRAM
  92 # include <stdlib.h>
  93 int main(void)
  94 {
  95         const char *path, *name, *num;
  96
  97         if (get_terminal_name(STDERR_FILENO, &path, &name, &num) == 0) {
  98                 fprintf(stderr, "tty path:   %s\n", path);
  99                 fprintf(stderr, "tty name:   %s\n", name);
 100                 fprintf(stderr, "tty number: %s\n", num);
 101         }
 102         fprintf(stderr,         "tty width:  %d\n", get_terminal_width(0));
 103
 104         return EXIT_SUCCESS;
 105 }
 106 #endif