flags.c

   1 /* flags.c -- Everything about flags except the `set' command.  That
   2    is in builtins.c */
   3
   4 /* Copyright (C) 1987,1989 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Bash, the Bourne Again SHell.
   7
   8 Bash is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License along
  19 with Bash; see the file COPYING.  If not, write to the Free Software
  20 Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  21
  22 /* Flags hacking. */
  23 #include "config.h"
  24 #if defined (HAVE_UNISTD_H)
  25 #  include <unistd.h>
  26 #endif
  27
  28 #include "shell.h"
  29 #include "flags.h"
  30
  31 #if defined (JOB_CONTROL)
  32 extern int set_job_control ();
  33 #endif
  34
  35 #if defined (RESTRICTED_SHELL)
  36 extern char *shell_name;
  37 #endif
  38
  39 /* -c, -s invocation options -- not really flags, but they show up in $- */
  40 extern int want_pending_command, read_from_stdin;
  41
  42 /* **************************************************************** */
  43 /*                                                                  */
  44 /*                      The Standard Sh Flags.                      */
  45 /*                                                                  */
  46 /* **************************************************************** */
  47
  48 /* Non-zero means automatically mark variables which are modified or created
  49    as auto export variables. */
  50 int mark_modified_vars = 0;
  51
  52 /* Non-zero causes asynchronous job notification.  Otherwise, job state
  53    notification only takes place just before a primary prompt is printed. */
  54 int asynchronous_notification = 0;
  55
  56 /* Non-zero means exit immediately if a command exits with a non-zero
  57    exit status. */
  58 int exit_immediately_on_error = 0;
  59
  60 /* Non-zero means disable filename globbing. */
  61 int disallow_filename_globbing = 0;
  62
  63 /* Non-zero means that all keyword arguments are placed into the environment
  64    for a command, not just those that appear on the line before the command
  65    name. */
  66 int place_keywords_in_env = 0;
  67
  68 /* Non-zero means read commands, but don't execute them.  This is useful
  69    for debugging shell scripts that should do something hairy and possibly
  70    desctructive. */
  71 int read_but_dont_execute = 0;
  72
  73 /* Non-zero means end of file is after one command. */
  74 int just_one_command = 0;
  75
  76 /* Non-zero means don't overwrite existing files while doing redirections. */
  77 int noclobber = 0;
  78
  79 /* Non-zero means trying to get the value of $i where $i is undefined
  80    causes an error, instead of a null substitution. */
  81 int unbound_vars_is_error = 0;
  82
  83 /* Non-zero means type out input lines after you read them. */
  84 int echo_input_at_read = 0;
  85
  86 /* Non-zero means type out the command definition after reading, but
  87    before executing. */
  88 int echo_command_at_execute = 0;
  89
  90 /* Non-zero means turn on the job control features. */
  91 int jobs_m_flag = 0;
  92
  93 /* Non-zero means this shell is interactive, even if running under a
  94    pipe. */
  95 int forced_interactive = 0;
  96
  97 /* By default, follow the symbolic links as if they were real directories
  98    while hacking the `cd' command.  This means that `cd ..' moves up in
  99    the string of symbolic links that make up the current directory, instead
 100    of the absolute directory.  The shell variable `nolinks' also controls
 101    this flag. */
 102 int no_symbolic_links = 0;
 103
 104 /* **************************************************************** */
 105 /*                                                                  */
 106 /*                   Non-Standard Flags Follow Here.                */
 107 /*                                                                  */
 108 /* **************************************************************** */
 109
 110 #if 0
 111 /* Non-zero means do lexical scoping in the body of a FOR command. */
 112 int lexical_scoping = 0;
 113 #endif
 114
 115 /* Non-zero means no such thing as invisible variables. */
 116 int no_invisible_vars = 0;
 117
 118 /* Non-zero means look up and remember command names in a hash table, */
 119 int hashing_enabled = 1;
 120
 121 #if defined (BANG_HISTORY)
 122 /* Non-zero means that we are doing history expansion.  The default.
 123    This means !22 gets the 22nd line of history. */
 124 int history_expansion = 1;
 125 #endif /* BANG_HISTORY */
 126
 127 /* Non-zero means that we allow comments to appear in interactive commands. */
 128 int interactive_comments = 1;
 129
 130 #if defined (RESTRICTED_SHELL)
 131 /* Non-zero means that this shell is `restricted'.  A restricted shell
 132    disallows: changing directories, command or path names containing `/',
 133    unsetting or resetting the values of $PATH and $SHELL, and any type of
 134    output redirection. */
 135 int restricted = 0;             /* currently restricted */
 136 int restricted_shell = 0;       /* shell was started in restricted mode. */
 137 #endif /* RESTRICTED_SHELL */
 138
 139 /* Non-zero means that this shell is running in `privileged' mode.  This
 140    is required if the shell is to run setuid.  If the `-p' option is
 141    not supplied at startup, and the real and effective uids or gids
 142    differ, disable_priv_mode is called to relinquish setuid status. */
 143 int privileged_mode = 0;
 144
 145 #if defined (BRACE_EXPANSION)
 146 /* Zero means to disable brace expansion: foo{a,b} -> fooa foob */
 147 int brace_expansion = 1;
 148 #endif
 149
 150 /* **************************************************************** */
 151 /*                                                                  */
 152 /*                      The Flags ALIST.                            */
 153 /*                                                                  */
 154 /* **************************************************************** */
 155
 156 struct flags_alist shell_flags[] = {
 157   /* Standard sh flags. */
 158   { 'a', &mark_modified_vars },
 159 #if defined (JOB_CONTROL)
 160   { 'b', &asynchronous_notification },
 161 #endif /* JOB_CONTROL */
 162   { 'e', &exit_immediately_on_error },
 163   { 'f', &disallow_filename_globbing },
 164   { 'h', &hashing_enabled },
 165   { 'i', &forced_interactive },
 166   { 'k', &place_keywords_in_env },
 167 #if defined (JOB_CONTROL)
 168   { 'm', &jobs_m_flag },
 169 #endif /* JOB_CONTROL */
 170   { 'n', &read_but_dont_execute },
 171   { 'p', &privileged_mode },
 172 #if defined (RESTRICTED_SHELL)
 173   { 'r', &restricted },
 174 #endif /* RESTRICTED_SHELL */
 175   { 't', &just_one_command },
 176   { 'u', &unbound_vars_is_error },
 177   { 'v', &echo_input_at_read },
 178   { 'x', &echo_command_at_execute },
 179   { 'C', &noclobber },
 180
 181   /* New flags that control non-standard things. */
 182 #if 0
 183   { 'l', &lexical_scoping },
 184 #endif
 185   { 'I', &no_invisible_vars },
 186
 187   { 'P', &no_symbolic_links },
 188
 189 #if defined (BRACE_EXPANSION)
 190   { 'B', &brace_expansion },
 191 #endif
 192
 193 #if defined (BANG_HISTORY)
 194   { 'H', &history_expansion },
 195 #endif /* BANG_HISTORY */
 196
 197   {0, (int *)NULL}
 198 };
 199
 200 #define NUM_SHELL_FLAGS (sizeof (shell_flags) / sizeof (struct flags_alist))
 201
 202 int *
 203 find_flag (name)
 204      int name;
 205 {
 206   int i;
 207   for (i = 0; shell_flags[i].name; i++)
 208     {
 209       if (shell_flags[i].name == name)
 210         return (shell_flags[i].value);
 211     }
 212   return (FLAG_UNKNOWN);
 213 }
 214
 215 /* Change the state of a flag, and return it's original value, or return
 216    FLAG_ERROR if there is no flag FLAG.  ON_OR_OFF must be either
 217    FLAG_ON or FLAG_OFF. */
 218 int
 219 change_flag (flag, on_or_off)
 220   int flag;
 221   int on_or_off;
 222 {
 223   int *value, old_value;
 224
 225 #if defined (RESTRICTED_SHELL)
 226   /* Don't allow "set +r" in a shell which is `restricted'. */
 227   if (restricted && flag == 'r' && on_or_off == FLAG_OFF)
 228     return (FLAG_ERROR);
 229 #endif /* RESTRICTED_SHELL */
 230
 231   value = find_flag (flag);
 232
 233   if ((value == (int *)FLAG_UNKNOWN) || (on_or_off != FLAG_ON && on_or_off != FLAG_OFF))
 234     return (FLAG_ERROR);
 235
 236   old_value = *value;
 237
 238   *value = (on_or_off == FLAG_ON) ? 1 : 0;
 239
 240   /* Special cases for a few flags. */
 241   switch (flag)
 242     {
 243 #if defined (JOB_CONTROL)
 244     case 'm':
 245       set_job_control (on_or_off == FLAG_ON);
 246       break;
 247 #endif /* JOB_CONTROL */
 248
 249 #if defined (RESTRICTED_SHELL)
 250     case 'r':
 251       if (on_or_off == FLAG_ON)
 252         maybe_make_restricted (shell_name);
 253       break;
 254 #endif
 255
 256 #if defined (BANG_HISTORY)
 257     case 'H':
 258       if (on_or_off == FLAG_ON)
 259         bash_initialize_history ();
 260       break;
 261 #endif
 262
 263     case 'p':
 264       if (on_or_off == FLAG_OFF)
 265         disable_priv_mode ();
 266
 267       break;
 268     }
 269
 270   return (old_value);
 271 }
 272
 273 /* Return a string which is the names of all the currently
 274    set shell flags. */
 275 char *
 276 which_set_flags ()
 277 {
 278   char *temp;
 279   int i, string_index;
 280
 281   temp = xmalloc (1 + NUM_SHELL_FLAGS + read_from_stdin + want_pending_command);
 282   for (i = string_index = 0; shell_flags[i].name; i++)
 283     if (*(shell_flags[i].value))
 284       temp[string_index++] = shell_flags[i].name;
 285
 286   if (want_pending_command)
 287     temp[string_index++] = 'c';
 288   if (read_from_stdin)
 289     temp[string_index++] = 's';
 290
 291   temp[string_index] = '\0';
 292   return (temp);
 293 }
 294
 295 void
 296 reset_shell_flags ()
 297 {
 298   mark_modified_vars = exit_immediately_on_error = disallow_filename_globbing = 0;
 299   place_keywords_in_env = read_but_dont_execute = just_one_command = 0;
 300   noclobber = unbound_vars_is_error = echo_input_at_read = 0;
 301   echo_command_at_execute = jobs_m_flag = forced_interactive = 0;
 302   no_symbolic_links = no_invisible_vars = privileged_mode = 0;
 303
 304   hashing_enabled = interactive_comments = 1;
 305
 306 #if defined (JOB_CONTROL)
 307   asynchronous_notification = 0;
 308 #endif
 309
 310 #if defined (BANG_HISTORY)
 311   history_expansion = 1;
 312 #endif
 313
 314 #if defined (BRACE_EXPANSION)
 315   brace_expansion = 1;
 316 #endif
 317
 318 #if defined (RESTRICTED_SHELL)
 319   restricted = 0;
 320 #endif
 321 }