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 1, 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, 675 Mass Ave, Cambridge, MA 02139, 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 /* **************************************************************** */
  40 /*                                                                  */
  41 /*                      The Standard Sh Flags.                      */
  42 /*                                                                  */
  43 /* **************************************************************** */
  44
  45 /* Non-zero means automatically mark variables which are modified or created
  46    as auto export variables. */
  47 int mark_modified_vars = 0;
  48
  49 /* Non-zero causes asynchronous job notification.  Otherwise, job state
  50    notification only takes place just before a primary prompt is printed. */
  51 int asynchronous_notification = 0;
  52
  53 /* Non-zero means exit immediately if a command exits with a non-zero
  54    exit status. */
  55 int exit_immediately_on_error = 0;
  56
  57 /* Non-zero means disable filename globbing. */
  58 int disallow_filename_globbing = 0;
  59
  60 /* Non-zero means that all keyword arguments are placed into the environment
  61    for a command, not just those that appear on the line before the command
  62    name. */
  63 int place_keywords_in_env = 0;
  64
  65 /* Non-zero means read commands, but don't execute them.  This is useful
  66    for debugging shell scripts that should do something hairy and possibly
  67    desctructive. */
  68 int read_but_dont_execute = 0;
  69
  70 /* Non-zero means end of file is after one command. */
  71 int just_one_command = 0;
  72
  73 /* Non-zero means don't overwrite existing files while doing redirections. */
  74 int noclobber = 0;
  75
  76 /* Non-zero means trying to get the value of $i where $i is undefined
  77    causes an error, instead of a null substitution. */
  78 int unbound_vars_is_error = 0;
  79
  80 /* Non-zero means type out input lines after you read them. */
  81 int echo_input_at_read = 0;
  82
  83 /* Non-zero means type out the command definition after reading, but
  84    before executing. */
  85 int echo_command_at_execute = 0;
  86
  87 /* Non-zero means turn on the job control features. */
  88 int jobs_m_flag = 0;
  89
  90 /* Non-zero means this shell is interactive, even if running under a
  91    pipe. */
  92 int forced_interactive = 0;
  93
  94 /* By default, follow the symbolic links as if they were real directories
  95    while hacking the `cd' command.  This means that `cd ..' moves up in
  96    the string of symbolic links that make up the current directory, instead
  97    of the absolute directory.  The shell variable `nolinks' also controls
  98    this flag. */
  99 int no_symbolic_links = 0;
 100
 101 /* **************************************************************** */
 102 /*                                                                  */
 103 /*                   Non-Standard Flags Follow Here.                */
 104 /*                                                                  */
 105 /* **************************************************************** */
 106
 107 #if 0
 108 /* Non-zero means do lexical scoping in the body of a FOR command. */
 109 int lexical_scoping = 0;
 110 #endif
 111
 112 /* Non-zero means no such thing as invisible variables. */
 113 int no_invisible_vars = 0;
 114
 115 /* Non-zero means look up and remember command names in a hash table, */
 116 int hashing_enabled = 1;
 117
 118 #if defined (BANG_HISTORY)
 119 /* Non-zero means that we are doing history expansion.  The default.
 120    This means !22 gets the 22nd line of history. */
 121 int history_expansion = 1;
 122 #endif /* BANG_HISTORY */
 123
 124 /* Non-zero means that we allow comments to appear in interactive commands. */
 125 int interactive_comments = 1;
 126
 127 #if defined (RESTRICTED_SHELL)
 128 /* Non-zero means that this shell is `restricted'.  A restricted shell
 129    disallows: changing directories, command or path names containing `/',
 130    unsetting or resetting the values of $PATH and $SHELL, and any type of
 131    output redirection. */
 132 int restricted = 0;
 133 #endif /* RESTRICTED_SHELL */
 134
 135 /* Non-zero means that this shell is running in `privileged' mode.  This
 136    is required if the shell is to run setuid.  If the `-p' option is
 137    not supplied at startup, and the real and effective uids or gids
 138    differ, disable_priv_mode is called to relinquish setuid status. */
 139 int privileged_mode = 0;
 140
 141 #if defined (BRACE_EXPANSION)
 142 /* Zero means to disable brace expansion: foo{a,b} -> fooa foob */
 143 int brace_expansion = 1;
 144 #endif
 145
 146 /* **************************************************************** */
 147 /*                                                                  */
 148 /*                      The Flags ALIST.                            */
 149 /*                                                                  */
 150 /* **************************************************************** */
 151
 152 struct flags_alist shell_flags[] = {
 153   /* Standard sh flags. */
 154   { 'a', &mark_modified_vars },
 155 #if defined (JOB_CONTROL)
 156   { 'b', &asynchronous_notification },
 157 #endif /* JOB_CONTROL */
 158   { 'e', &exit_immediately_on_error },
 159   { 'f', &disallow_filename_globbing },
 160   { 'h', &hashing_enabled },
 161   { 'i', &forced_interactive },
 162   { 'k', &place_keywords_in_env },
 163 #if defined (JOB_CONTROL)
 164   { 'm', &jobs_m_flag },
 165 #endif /* JOB_CONTROL */
 166   { 'n', &read_but_dont_execute },
 167   { 'p', &privileged_mode },
 168 #if defined (RESTRICTED_SHELL)
 169   { 'r', &restricted },
 170 #endif /* RESTRICTED_SHELL */
 171   { 't', &just_one_command },
 172   { 'u', &unbound_vars_is_error },
 173   { 'v', &echo_input_at_read },
 174   { 'x', &echo_command_at_execute },
 175   { 'C', &noclobber },
 176
 177   /* New flags that control non-standard things. */
 178 #if 0
 179   { 'l', &lexical_scoping },
 180 #endif
 181   { 'I', &no_invisible_vars },
 182
 183   { 'P', &no_symbolic_links },
 184
 185 #if defined (BRACE_EXPANSION)
 186   { 'B', &brace_expansion },
 187 #endif
 188
 189 #if defined (BANG_HISTORY)
 190   { 'H', &history_expansion },
 191 #endif /* BANG_HISTORY */
 192
 193   {0, (int *)NULL}
 194 };
 195
 196 #define NUM_SHELL_FLAGS (sizeof (shell_flags) / sizeof (struct flags_alist))
 197
 198 int *
 199 find_flag (name)
 200      int name;
 201 {
 202   int i;
 203   for (i = 0; shell_flags[i].name; i++)
 204     {
 205       if (shell_flags[i].name == name)
 206         return (shell_flags[i].value);
 207     }
 208   return (FLAG_UNKNOWN);
 209 }
 210
 211 /* Change the state of a flag, and return it's original value, or return
 212    FLAG_ERROR if there is no flag called NAME.  ON_OR_OFF should be one
 213    of FLAG_ON or FLAG_OFF. */
 214 int
 215 change_flag (flag, on_or_off)
 216   int flag;
 217   int on_or_off;
 218 {
 219   int *value, old_value;
 220
 221   value = find_flag (flag);
 222
 223 #if defined (RESTRICTED_SHELL)
 224   /* Don't allow "set +r" in a shell which is `restricted'. */
 225   if (restricted && flag == 'r' && on_or_off == FLAG_OFF)
 226     return (FLAG_ERROR);
 227 #endif /* RESTRICTED_SHELL */
 228
 229   if (value == (int *)FLAG_UNKNOWN)
 230     return (FLAG_ERROR);
 231
 232   old_value = *value;
 233
 234   if (on_or_off == FLAG_ON)
 235     *value = 1;
 236   else if (on_or_off == FLAG_OFF)
 237     *value = 0;
 238   else
 239     return (FLAG_ERROR);
 240
 241   /* Special cases for a few flags. */
 242   switch (flag)
 243     {
 244 #if defined (JOB_CONTROL)
 245     case 'm':
 246       set_job_control (on_or_off == FLAG_ON);
 247       break;
 248 #endif /* JOB_CONTROL */
 249
 250 #if defined (RESTRICTED_SHELL)
 251     case 'r':
 252       if (on_or_off == FLAG_ON)
 253         maybe_make_restricted (shell_name);
 254       break;
 255 #endif
 256
 257 #if defined (BANG_HISTORY)
 258     case 'H':
 259       if (on_or_off == FLAG_ON)
 260         bash_initialize_history ();
 261       break;
 262 #endif
 263
 264     case 'p':
 265       if (on_or_off == FLAG_OFF)
 266         disable_priv_mode ();
 267
 268       break;
 269     }
 270
 271   return (old_value);
 272 }
 273
 274 /* Return a string which is the names of all the currently
 275    set shell flags. */
 276 char *
 277 which_set_flags ()
 278 {
 279   char *temp;
 280   int i, string_index;
 281
 282   temp = xmalloc (1 + NUM_SHELL_FLAGS);
 283   for (i = string_index = 0; shell_flags[i].name; i++)
 284     if (*(shell_flags[i].value))
 285       temp[string_index++] = shell_flags[i].name;
 286
 287   temp[string_index] = '\0';
 288   return (temp);
 289 }
 290
 291 void
 292 reset_shell_flags ()
 293 {
 294   mark_modified_vars = exit_immediately_on_error = disallow_filename_globbing = 0;
 295   place_keywords_in_env = read_but_dont_execute = just_one_command = 0;
 296   noclobber = unbound_vars_is_error = echo_input_at_read = 0;
 297   echo_command_at_execute = jobs_m_flag = forced_interactive = 0;
 298   no_symbolic_links = no_invisible_vars = privileged_mode = 0;
 299
 300   hashing_enabled = interactive_comments = 1;
 301
 302 #if defined (JOB_CONTROL)
 303   asynchronous_notification = 0;
 304 #endif
 305
 306 #if defined (BANG_HISTORY)
 307   history_expansion = 1;
 308 #endif
 309
 310 #if defined (BRACE_EXPANSION)
 311   brace_expansion = 1;
 312 #endif
 313
 314 #if defined (RESTRICTED_SHELL)
 315   restricted = 0;
 316 #endif
 317 }