src/getlimits.c

   1 /* getlimits - print various platform dependent limits.
   2    Copyright (C) 2008-2009 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Pádraig Brady  */
  18
  19 #include <config.h>             /* sets _FILE_OFFSET_BITS=64 etc. */
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22
  23 #include "system.h"
  24 #include "c-ctype.h"
  25 #include "long-options.h"
  26
  27 #define PROGRAM_NAME "getlimits"
  28
  29 #define AUTHORS proper_name_utf8 ("Padraig Brady", "P\303\241draig Brady")
  30
  31 #ifndef TIME_T_MAX
  32 # define TIME_T_MAX TYPE_MAXIMUM (time_t)
  33 #endif
  34
  35 #ifndef TIME_T_MIN
  36 # define TIME_T_MIN TYPE_MINIMUM (time_t)
  37 #endif
  38
  39 #ifndef SSIZE_MIN
  40 # define SSIZE_MIN TYPE_MINIMUM (ssize_t)
  41 #endif
  42
  43 #ifndef PID_T_MIN
  44 # define PID_T_MIN TYPE_MINIMUM (pid_t)
  45 #endif
  46
  47 /* These are not interesting to print.
  48  * Instead of these defines it would be nice to be able to do
  49  * #ifdef (TYPE##_MIN) in function macro below.  */
  50 #define SIZE_MIN 0
  51 #define UCHAR_MIN 0
  52 #define UINT_MIN 0
  53 #define ULONG_MIN 0
  54 #define UINTMAX_MIN 0
  55 #define UID_T_MIN 0
  56 #define GID_T_MIN 0
  57
  58 void
  59 usage (int status)
  60 {
  61   if (status != EXIT_SUCCESS)
  62     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  63              program_name);
  64   else
  65     {
  66       printf (_("\
  67 Usage: %s\n\
  68 "), program_name);
  69
  70       fputs (_("\
  71 Output platform dependent limits in a format useful for shell scripts.\n\
  72 \n\
  73 "), stdout);
  74       fputs (HELP_OPTION_DESCRIPTION, stdout);
  75       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  76       emit_bug_reporting_address ();
  77     }
  78   exit (status);
  79 }
  80
  81 /* Add absolute values of ascii decimal strings.
  82  * Strings can have leading spaces.
  83  * If any string has a '-' it's preserved in the output:
  84  * I.E.
  85  *    1 +  1 ->  2
  86  *   -1 + -1 -> -2
  87  *   -1 +  1 -> -2
  88  *    1 + -1 -> -2
  89  */
  90 static char *
  91 decimal_ascii_add (const char *str1, const char *str2)
  92 {
  93   int len1 = strlen (str1);
  94   int len2 = strlen (str2);
  95   int rlen = MAX (len1, len2) + 3;  /* space for extra digit or sign + NUL */
  96   char *result = xmalloc (rlen);
  97   char *rp = result + rlen - 1;
  98   const char *d1 = str1 + len1 - 1;
  99   const char *d2 = str2 + len2 - 1;
 100   int carry = 0;
 101   *rp = '\0';
 102
 103   while (1)
 104     {
 105       char c1 = (d1 < str1 ? ' ' : (*d1 == '-' ? ' ' : *d1--));
 106       char c2 = (d2 < str2 ? ' ' : (*d2 == '-' ? ' ' : *d2--));
 107       char t1 = c1 + c2 + carry;    /* ASCII digits are BCD */
 108       if (!c_isdigit (c1) && !c_isdigit (c2) && !carry)
 109         break;
 110       carry = t1 > '0' + '9' || t1 == ' ' + '9' + 1;
 111       t1 += 6 * carry;
 112       *--rp = (t1 & 0x0F) | 0x30;   /* top nibble to ASCII */
 113     }
 114   if ((d1 >= str1 && *d1 == '-') || (d2 >= str2 && (*d2 == '-')))
 115     *--rp = '-';
 116
 117   if (rp != result)
 118     memmove (result, rp, rlen - (rp - result));
 119
 120   return result;
 121 }
 122
 123 int
 124 main (int argc, char **argv)
 125 {
 126   char limit[64];               /* big enough for 128 bit at least */
 127   char *oflow;
 128
 129   initialize_main (&argc, &argv);
 130   set_program_name (argv[0]);
 131   setlocale (LC_ALL, "");
 132   bindtextdomain (PACKAGE, LOCALEDIR);
 133   textdomain (PACKAGE);
 134
 135   initialize_exit_failure (EXIT_FAILURE);
 136   atexit (close_stdout);
 137
 138   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, VERSION,
 139                       usage, AUTHORS, (char const *) NULL);
 140
 141 #define print_int(TYPE)                                                  \
 142   snprintf (limit, sizeof(limit), "%"PRIuMAX, (uintmax_t)TYPE##_MAX);    \
 143   printf (#TYPE"_MAX=%s\n", limit);                                      \
 144   oflow = decimal_ascii_add (limit, "1");                                \
 145   printf (#TYPE"_OFLOW=%s\n", oflow);                                    \
 146   free (oflow);                                                          \
 147   if (TYPE##_MIN)                                                        \
 148     {                                                                    \
 149       snprintf (limit, sizeof(limit), "%"PRIdMAX, (intmax_t)TYPE##_MIN); \
 150       printf (#TYPE"_MIN=%s\n", limit);                                  \
 151       oflow = decimal_ascii_add (limit, "-1");                           \
 152       printf (#TYPE"_UFLOW=%s\n", oflow);                                \
 153       free (oflow);                                                      \
 154     }
 155
 156   /* Variable sized ints */
 157   print_int (CHAR);
 158   print_int (SCHAR);
 159   print_int (UCHAR);
 160   print_int (SHRT);
 161   print_int (INT);
 162   print_int (UINT);
 163   print_int (LONG);
 164   print_int (ULONG);
 165   print_int (SIZE);
 166   print_int (SSIZE);
 167   print_int (TIME_T);
 168   print_int (UID_T);
 169   print_int (GID_T);
 170   print_int (PID_T);
 171   print_int (OFF_T);
 172   print_int (INTMAX);
 173   print_int (UINTMAX);
 174 }