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
  14 static int get_env_int(const char *name)
  15 {
  16         const char *cp = getenv(name);
  17
  18         if (cp) {
  19                 char *end = NULL;
  20                 long x;
  21
  22                 errno = 0;
  23                 x = strtol(cp, &end, 10);
  24
  25                 if (errno == 0 && end && *end == '\0' && end > cp &&
  26                     x > 0 && x <= INT_MAX)
  27                         return x;
  28         }
  29
  30         return -1;
  31 }
  32
  33 int get_terminal_dimension(int *cols, int *lines)
  34 {
  35         int c = 0, l = 0;
  36
  37 #if defined(TIOCGWINSZ)
  38         struct winsize  w_win;
  39         if (ioctl (STDOUT_FILENO, TIOCGWINSZ, &w_win) == 0) {
  40                 c = w_win.ws_col;
  41                 l = w_win.ws_row;
  42         }
  43 #elif defined(TIOCGSIZE)
  44         struct ttysize  t_win;
  45         if (ioctl (STDOUT_FILENO, TIOCGSIZE, &t_win) == 0) {
  46                 c = t_win.ts_cols;
  47                 l = t_win.ts_lines;
  48         }
  49 #endif
  50         if (cols) {
  51                 if (c <= 0)
  52                         c = get_env_int("COLUMNS");
  53                 *cols = c;
  54         }
  55         if (lines) {
  56                 if (l <= 0)
  57                         l = get_env_int("LINES");
  58                 *lines = l;
  59         }
  60         return 0;
  61 }
  62
  63 int get_terminal_width(int default_width)
  64 {
  65         int width = 0;
  66
  67         get_terminal_dimension(&width, NULL);
  68
  69         return width > 0 ? width : default_width;
  70 }
  71
  72 int get_terminal_stdfd(void)
  73 {
  74         if (isatty(STDIN_FILENO))
  75                 return STDIN_FILENO;
  76         else if (isatty(STDOUT_FILENO))
  77                 return STDOUT_FILENO;
  78         else if (isatty(STDERR_FILENO))
  79                 return STDERR_FILENO;
  80
  81         return -EINVAL;
  82 }
  83
  84 int get_terminal_name(const char **path,
  85                       const char **name,
  86                       const char **number)
  87 {
  88         const char *tty;
  89         const char *p;
  90         int fd;
  91
  92
  93         if (name)
  94                 *name = NULL;
  95         if (path)
  96                 *path = NULL;
  97         if (number)
  98                 *number = NULL;
  99
 100         fd = get_terminal_stdfd();
 101         if (fd < 0)
 102                 return fd;      /* error */
 103
 104         tty = ttyname(fd);
 105         if (!tty)
 106                 return -1;
 107
 108         if (path)
 109                 *path = tty;
 110         if (name || number)
 111                 tty = strncmp(tty, "/dev/", 5) == 0 ? tty + 5 : tty;
 112         if (name)
 113                 *name = tty;
 114         if (number) {
 115                 for (p = tty; p && *p; p++) {
 116                         if (isdigit(*p)) {
 117                                 *number = p;
 118                                 break;
 119                         }
 120                 }
 121         }
 122         return 0;
 123 }
 124
 125 int get_terminal_type(const char **type)
 126 {
 127         *type = getenv("TERM");
 128         if (*type)
 129                 return -EINVAL;
 130         return 0;
 131 }
 132
 133 #ifdef TEST_PROGRAM_TTYUTILS
 134 # include <stdlib.h>
 135 int main(void)
 136 {
 137         const char *path, *name, *num;
 138         int c, l;
 139
 140         if (get_terminal_name(&path, &name, &num) == 0) {
 141                 fprintf(stderr, "tty path:   %s\n", path);
 142                 fprintf(stderr, "tty name:   %s\n", name);
 143                 fprintf(stderr, "tty number: %s\n", num);
 144         }
 145         get_terminal_dimension(&c, &l);
 146         fprintf(stderr,         "tty cols:   %d\n", c);
 147         fprintf(stderr,         "tty lines:  %d\n", l);
 148
 149
 150         return EXIT_SUCCESS;
 151 }
 152 #endif /* TEST_PROGRAM_TTYUTILS */