src/getlimits.c

   1 /* getlimits - print various platform dependent limits.
   2    Copyright (C) 2008-2024 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 <https://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 #include <float.h>
  23
  24 #include "ftoastr.h"
  25 #include "system.h"
  26 #include "long-options.h"
  27
  28 #define PROGRAM_NAME "getlimits"
  29
  30 #define AUTHORS proper_name_lite ("Padraig Brady", "P\303\241draig Brady")
  31
  32 #ifndef TIME_T_MAX
  33 # define TIME_T_MAX TYPE_MAXIMUM (time_t)
  34 #endif
  35
  36 #ifndef TIME_T_MIN
  37 # define TIME_T_MIN TYPE_MINIMUM (time_t)
  38 #endif
  39
  40 #ifndef SSIZE_MIN
  41 # define SSIZE_MIN TYPE_MINIMUM (ssize_t)
  42 #endif
  43
  44 #ifndef PID_T_MIN
  45 # define PID_T_MIN TYPE_MINIMUM (pid_t)
  46 #endif
  47
  48 /* These are not interesting to print.
  49  * Instead of these defines it would be nice to be able to do
  50  * #ifdef (TYPE##_MIN) in function macro below.  */
  51 #define SIZE_MIN 0
  52 #define UCHAR_MIN 0
  53 #define UINT_MIN 0
  54 #define ULONG_MIN 0
  55 #define UINTMAX_MIN 0
  56 #define UID_T_MIN 0
  57 #define GID_T_MIN 0
  58
  59 void
  60 usage (int status)
  61 {
  62   if (status != EXIT_SUCCESS)
  63     emit_try_help ();
  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_ancillary_info (PROGRAM_NAME);
  77     }
  78   exit (status);
  79 }
  80
  81 /* Add one to the absolute value of the number whose textual
  82    representation is BUF + 1.  Do this in-place, in the buffer.
  83    Return a pointer to the result, which is normally BUF + 1, but is
  84    BUF if the representation grew in size.  */
  85 static char const *
  86 decimal_absval_add_one (char *buf)
  87 {
  88   bool negative = (buf[1] == '-');
  89   char *absnum = buf + 1 + negative;
  90   char *p = absnum + strlen (absnum);
  91   absnum[-1] = '0';
  92   while (*--p == '9')
  93     *p = '0';
  94   ++*p;
  95   char *result = MIN (absnum, p);
  96   if (negative)
  97     *--result = '-';
  98   return result;
  99 }
 100
 101 #define PRINT_FLOATTYPE(N, T, FTOASTR, BUFSIZE)                         \
 102 static void                                                             \
 103 N (T x)                                                                 \
 104 {                                                                       \
 105   char buf[BUFSIZE];                                                    \
 106   FTOASTR (buf, sizeof buf, FTOASTR_LEFT_JUSTIFY, 0, x);                \
 107   puts (buf);                                                           \
 108 }
 109
 110 PRINT_FLOATTYPE (print_FLT, float, ftoastr, FLT_BUFSIZE_BOUND)
 111 PRINT_FLOATTYPE (print_DBL, double, dtoastr, DBL_BUFSIZE_BOUND)
 112 PRINT_FLOATTYPE (print_LDBL, long double, ldtoastr, LDBL_BUFSIZE_BOUND)
 113
 114 int
 115 main (int argc, char **argv)
 116 {
 117   char limit[1 + MAX (INT_BUFSIZE_BOUND (intmax_t),
 118                       INT_BUFSIZE_BOUND (uintmax_t))];
 119
 120   initialize_main (&argc, &argv);
 121   set_program_name (argv[0]);
 122   setlocale (LC_ALL, "");
 123   bindtextdomain (PACKAGE, LOCALEDIR);
 124   textdomain (PACKAGE);
 125
 126   atexit (close_stdout);
 127
 128   parse_gnu_standard_options_only (argc, argv, PROGRAM_NAME, PACKAGE_NAME,
 129                                    VERSION, true, usage, AUTHORS,
 130                                    (char const *) nullptr);
 131
 132 #define print_int(TYPE)                                                  \
 133   sprintf (limit + 1, "%ju", (uintmax_t) TYPE##_MAX);               \
 134   printf (#TYPE"_MAX=%s\n", limit + 1);                                  \
 135   printf (#TYPE"_OFLOW=%s\n", decimal_absval_add_one (limit));           \
 136   if (TYPE##_MIN)                                                        \
 137     {                                                                    \
 138       sprintf (limit + 1, "%jd", (intmax_t) TYPE##_MIN);            \
 139       printf (#TYPE"_MIN=%s\n", limit + 1);                              \
 140       printf (#TYPE"_UFLOW=%s\n", decimal_absval_add_one (limit));       \
 141     }
 142
 143 #define print_float(TYPE)                                                \
 144   printf (#TYPE"_MIN="); print_##TYPE (TYPE##_MIN);                      \
 145   printf (#TYPE"_MAX="); print_##TYPE (TYPE##_MAX);
 146
 147   /* Variable sized ints */
 148   print_int (CHAR);
 149   print_int (SCHAR);
 150   print_int (UCHAR);
 151   print_int (SHRT);
 152   print_int (INT);
 153   print_int (UINT);
 154   print_int (LONG);
 155   print_int (ULONG);
 156   print_int (SIZE);
 157   print_int (SSIZE);
 158   print_int (TIME_T);
 159   print_int (UID_T);
 160   print_int (GID_T);
 161   print_int (PID_T);
 162   print_int (OFF_T);
 163   print_int (INTMAX);
 164   print_int (UINTMAX);
 165
 166   /* Variable sized floats */
 167   print_float (FLT);
 168   print_float (DBL);
 169   print_float (LDBL);
 170
 171   return EXIT_SUCCESS;
 172 }