src/builtins/help.c

   1 /*
   2    psh/builtins/hash.c - builtin command hash
   3
   4    Copyright 2020 Zhang Maiyun.
   5
   6    This file is part of Psh, P shell.
   7
   8    Psh is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    Psh is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20 */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29
  30 #include "builtin.h"
  31 #include "libpsh/util.h"
  32 #include "psh.h"
  33
  34 #define MAN 0x00
  35 #define SHORT 0x01
  36 #define USAGE 0x02
  37 #define NBUILTIN (sizeof(builtin_helps) / sizeof(builtin_help_t))
  38 /* Help string of all builtins */
  39 #ifndef WITHOUT_BUILTIN_HELP
  40 typedef char *builtin_help_t[4];
  41 const builtin_help_t builtin_helps[63] = {
  42     {".", "filename [arguments]",
  43      "Execute commands from a file in the current shell.",
  44      "Read and execute commands from FILENAME in the current shell.  The "
  45      "entries in $PATH are used to find the directory containing FILENAME. If "
  46      "any ARGUMENTS are supplied, they become the positional parameters when "
  47      "FILENAME is executed.\n"
  48      "\tExit Status:\n"
  49      "\tReturns the status of the last command executed in FILENAME; fails if "
  50      "FILENAME cannot be read."},
  51     {":", "", "", ""},
  52     {"alias", "", "", ""},
  53     {"bg", "", "", ""},
  54     {"bind", "", "", ""},
  55     {"break", "", "", ""},
  56     {"builtin", "", "", ""},
  57     {"case", "", "", ""},
  58     {"cd", "", "", ""},
  59     {"chdir", "", "", ""},
  60     {"command", "", "", ""},
  61     {"continue", "", "", ""},
  62     {"declare", "", "", ""},
  63     {"do", "", "", ""},
  64     {"done", "", "", ""},
  65     {"echo", "", "", ""},
  66     {"elif", "", "", ""},
  67     {"else", "", "", ""},
  68     {"esac", "", "", ""},
  69     {"eval", "", "", ""},
  70     {"exec", "", "", ""},
  71     {"exit", "", "", ""},
  72     {"export", "", "", ""},
  73     {"false", "", "", ""},
  74     {"fc", "", "", ""},
  75     {"fg", "", "", ""},
  76     {"fi", "", "", ""},
  77     {"for", "", "", ""},
  78     {"getopts", "", "", ""},
  79     {"getstat", "", "", ""},
  80     {"hash", "", "", ""},
  81     {"help", "", "", ""},
  82     {"history", "", "", ""},
  83     {"if", "", "", ""},
  84     {"jobid", "", "", ""},
  85     {"jobs", "", "", ""},
  86     {"local", "", "", ""},
  87     {"logout", "", "", ""},
  88     {"popd", "", "", ""},
  89     {"pushd", "", "", ""},
  90     {"pwd", "", "", ""},
  91     {"quit", "", "", ""},
  92     {"read", "", "", ""},
  93     {"readonly", "", "", ""},
  94     {"return", "", "", ""},
  95     {"set", "", "", ""},
  96     {"setvar", "", "", ""},
  97     {"shift", "", "", ""},
  98     {"source", "", "", ""},
  99     {"test", "", "", ""},
 100     {"then", "", "", ""},
 101     {"times", "", "", ""},
 102     {"trap", "", "", ""},
 103     {"true", "", "", ""},
 104     {"type", "", "", ""},
 105     {"ulimit", "", "", ""},
 106     {"umask", "", "", ""},
 107     {"unalias", "", "", ""},
 108     {"unset", "", "", ""},
 109     {"until", "", "", ""},
 110     {"wait", "", "", ""},
 111     {"which", "", "", ""},
 112     {"while", "", "", ""}};
 113 #endif
 114 static int compare_builtin_helps(const void *key, const void *cur)
 115 {
 116     return strcmp((char *)key, (*(builtin_help_t *)cur)[0]);
 117 }
 118
 119 int builtin_help(int argc, char **argv, psh_state *state)
 120 {
 121 #ifndef WITHOUT_BUILTIN_HELP
 122     int type = MAN;
 123     int count = 0;
 124     /* count always points to the next possible command name */
 125     while (++count < argc)
 126     {
 127         if (argv[count][0] != '-')
 128             break;
 129         if (argv[count][1] == '-')
 130         {
 131             /* Skip this -- */
 132             ++count;
 133             break;
 134         }
 135         if (argv[count][1] == '\0')
 136             /* Treat '-' as an argument. */
 137             break;
 138         if (argv[count][1] == 'm')
 139             type = MAN;
 140         else if (argv[count][1] == 's')
 141             type = SHORT;
 142         else if (argv[count][1] == 'd')
 143             type = USAGE;
 144         else
 145         {
 146             OUT2E("%s: %s: unrecognized argument -%c\n", state->argv0, argv[0],
 147                   argv[count][1]);
 148             return 1;
 149         }
 150     }
 151     if (count == argc)
 152     {
 153         size_t count2;
 154         /* Print all help */
 155         for (count2 = 0; count2 < NBUILTIN; ++count2)
 156         {
 157             printf("%s %s\n", builtin_helps[count2][0],
 158                    builtin_helps[count2][1]);
 159         }
 160         return 0;
 161     }
 162     /* Go over all positional parameters, print their help */
 163     for (; count < argc; ++count)
 164     {
 165         builtin_help_t *itm =
 166             bsearch(argv[count], builtin_helps, NBUILTIN,
 167                     sizeof(builtin_help_t), &compare_builtin_helps);
 168         if (itm == NULL)
 169         {
 170             OUT2E("%s: %s: no help topics match `%s'.  Try `help help' or `man "
 171                   "-k %s' or `info %s'.\n",
 172                   state->argv0, argv[0], argv[count], argv[count], argv[count]);
 173             continue;
 174         }
 175         if (type == MAN)
 176             /* Print help in man format. */
 177             printf("NAME\n\t%s - %s\n\nSYNOPSIS\n\t%s "
 178                    "%s\n\nDESCRIPTION\n\t%s\n\nSEE "
 179                    "ALSO\n\tpsh(1)\n\nIMPLEMENTATION\n\tpsh\n",
 180                    (*itm)[0], (*itm)[2], (*itm)[0], (*itm)[1], (*itm)[3]);
 181         else if (type == SHORT)
 182             printf("%s - %s\n", (*itm)[0], (*itm)[2]);
 183         else if (type == USAGE)
 184             printf("%s: %s %s\n", (*itm)[0], (*itm)[0], (*itm)[1]);
 185     }
 186     return 0;
 187 #else
 188     OUT2E("%s: %s: Built without builtin help.\n", state->argv0, argv[0]);
 189     return 1;
 190 #endif
 191 }