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 (BANG_HISTORY)
  32 #  include "bashhist.h"
  33 #endif
  34
  35 #if defined (JOB_CONTROL)
  36 extern int set_job_control __P((int));
  37 #endif
  38
  39 #if defined (RESTRICTED_SHELL)
  40 extern char *shell_name;
  41 #endif
  42
  43 /* -c, -s invocation options -- not really flags, but they show up in $- */
  44 extern int want_pending_command, read_from_stdin;
  45
  46 /* **************************************************************** */
  47 /*                                                                  */
  48 /*                      The Standard Sh Flags.                      */
  49 /*                                                                  */
  50 /* **************************************************************** */
  51
  52 /* Non-zero means automatically mark variables which are modified or created
  53    as auto export variables. */
  54 int mark_modified_vars = 0;
  55
  56 /* Non-zero causes asynchronous job notification.  Otherwise, job state
  57    notification only takes place just before a primary prompt is printed. */
  58 int asynchronous_notification = 0;
  59
  60 /* Non-zero means exit immediately if a command exits with a non-zero
  61    exit status. */
  62 int exit_immediately_on_error = 0;
  63
  64 /* Non-zero means disable filename globbing. */
  65 int disallow_filename_globbing = 0;
  66
  67 /* Non-zero means that all keyword arguments are placed into the environment
  68    for a command, not just those that appear on the line before the command
  69    name. */
  70 int place_keywords_in_env = 0;
  71
  72 /* Non-zero means read commands, but don't execute them.  This is useful
  73    for debugging shell scripts that should do something hairy and possibly
  74    destructive. */
  75 int read_but_dont_execute = 0;
  76
  77 /* Non-zero means end of file is after one command. */
  78 int just_one_command = 0;
  79
  80 /* Non-zero means don't overwrite existing files while doing redirections. */
  81 int noclobber = 0;
  82
  83 /* Non-zero means trying to get the value of $i where $i is undefined
  84    causes an error, instead of a null substitution. */
  85 int unbound_vars_is_error = 0;
  86
  87 /* Non-zero means type out input lines after you read them. */
  88 int echo_input_at_read = 0;
  89
  90 /* Non-zero means type out the command definition after reading, but
  91    before executing. */
  92 int echo_command_at_execute = 0;
  93
  94 /* Non-zero means turn on the job control features. */
  95 int jobs_m_flag = 0;
  96
  97 /* Non-zero means this shell is interactive, even if running under a
  98    pipe. */
  99 int forced_interactive = 0;
 100
 101 /* By default, follow the symbolic links as if they were real directories
 102    while hacking the `cd' command.  This means that `cd ..' moves up in
 103    the string of symbolic links that make up the current directory, instead
 104    of the absolute directory.  The shell variable `nolinks' also controls
 105    this flag. */
 106 int no_symbolic_links = 0;
 107
 108 /* **************************************************************** */
 109 /*                                                                  */
 110 /*                   Non-Standard Flags Follow Here.                */
 111 /*                                                                  */
 112 /* **************************************************************** */
 113
 114 #if 0
 115 /* Non-zero means do lexical scoping in the body of a FOR command. */
 116 int lexical_scoping = 0;
 117 #endif
 118
 119 /* Non-zero means no such thing as invisible variables. */
 120 int no_invisible_vars = 0;
 121
 122 /* Non-zero means look up and remember command names in a hash table, */
 123 int hashing_enabled = 1;
 124
 125 #if defined (BANG_HISTORY)
 126 /* Non-zero means that we are doing history expansion.  The default.
 127    This means !22 gets the 22nd line of history. */
 128 int history_expansion = 1;
 129 #endif /* BANG_HISTORY */
 130
 131 /* Non-zero means that we allow comments to appear in interactive commands. */
 132 int interactive_comments = 1;
 133
 134 #if defined (RESTRICTED_SHELL)
 135 /* Non-zero means that this shell is `restricted'.  A restricted shell
 136    disallows: changing directories, command or path names containing `/',
 137    unsetting or resetting the values of $PATH and $SHELL, and any type of
 138    output redirection. */
 139 int restricted = 0;             /* currently restricted */
 140 int restricted_shell = 0;       /* shell was started in restricted mode. */
 141 #endif /* RESTRICTED_SHELL */
 142
 143 /* Non-zero means that this shell is running in `privileged' mode.  This
 144    is required if the shell is to run setuid.  If the `-p' option is
 145    not supplied at startup, and the real and effective uids or gids
 146    differ, disable_priv_mode is called to relinquish setuid status. */
 147 int privileged_mode = 0;
 148
 149 #if defined (BRACE_EXPANSION)
 150 /* Zero means to disable brace expansion: foo{a,b} -> fooa foob */
 151 int brace_expansion = 1;
 152 #endif
 153
 154 /* **************************************************************** */
 155 /*                                                                  */
 156 /*                      The Flags ALIST.                            */
 157 /*                                                                  */
 158 /* **************************************************************** */
 159
 160 struct flags_alist shell_flags[] = {
 161   /* Standard sh flags. */
 162   { 'a', &mark_modified_vars },
 163 #if defined (JOB_CONTROL)
 164   { 'b', &asynchronous_notification },
 165 #endif /* JOB_CONTROL */
 166   { 'e', &exit_immediately_on_error },
 167   { 'f', &disallow_filename_globbing },
 168   { 'h', &hashing_enabled },
 169   { 'i', &forced_interactive },
 170   { 'k', &place_keywords_in_env },
 171 #if defined (JOB_CONTROL)
 172   { 'm', &jobs_m_flag },
 173 #endif /* JOB_CONTROL */
 174   { 'n', &read_but_dont_execute },
 175   { 'p', &privileged_mode },
 176 #if defined (RESTRICTED_SHELL)
 177   { 'r', &restricted },
 178 #endif /* RESTRICTED_SHELL */
 179   { 't', &just_one_command },
 180   { 'u', &unbound_vars_is_error },
 181   { 'v', &echo_input_at_read },
 182   { 'x', &echo_command_at_execute },
 183   { 'C', &noclobber },
 184
 185   /* New flags that control non-standard things. */
 186 #if 0
 187   { 'l', &lexical_scoping },
 188 #endif
 189   { 'I', &no_invisible_vars },
 190
 191   { 'P', &no_symbolic_links },
 192
 193 #if defined (BRACE_EXPANSION)
 194   { 'B', &brace_expansion },
 195 #endif
 196
 197 #if defined (BANG_HISTORY)
 198   { 'H', &history_expansion },
 199 #endif /* BANG_HISTORY */
 200
 201   {0, (int *)NULL}
 202 };
 203
 204 #define NUM_SHELL_FLAGS (sizeof (shell_flags) / sizeof (struct flags_alist))
 205
 206 char optflags[NUM_SHELL_FLAGS+4] = { '+' };
 207
 208 int *
 209 find_flag (name)
 210      int name;
 211 {
 212   int i;
 213   for (i = 0; shell_flags[i].name; i++)
 214     {
 215       if (shell_flags[i].name == name)
 216         return (shell_flags[i].value);
 217     }
 218   return (FLAG_UNKNOWN);
 219 }
 220
 221 /* Change the state of a flag, and return it's original value, or return
 222    FLAG_ERROR if there is no flag FLAG.  ON_OR_OFF must be either
 223    FLAG_ON or FLAG_OFF. */
 224 int
 225 change_flag (flag, on_or_off)
 226   int flag;
 227   int on_or_off;
 228 {
 229   int *value, old_value;
 230
 231 #if defined (RESTRICTED_SHELL)
 232   /* Don't allow "set +r" in a shell which is `restricted'. */
 233   if (restricted && flag == 'r' && on_or_off == FLAG_OFF)
 234     return (FLAG_ERROR);
 235 #endif /* RESTRICTED_SHELL */
 236
 237   value = find_flag (flag);
 238
 239   if ((value == (int *)FLAG_UNKNOWN) || (on_or_off != FLAG_ON && on_or_off != FLAG_OFF))
 240     return (FLAG_ERROR);
 241
 242   old_value = *value;
 243
 244   *value = (on_or_off == FLAG_ON) ? 1 : 0;
 245
 246   /* Special cases for a few flags. */
 247   switch (flag)
 248     {
 249 #if defined (BANG_HISTORY)
 250     case 'H':
 251       if (on_or_off == FLAG_ON)
 252         bash_initialize_history ();
 253       break;
 254 #endif
 255
 256 #if defined (JOB_CONTROL)
 257     case 'm':
 258       set_job_control (on_or_off == FLAG_ON);
 259       break;
 260 #endif /* JOB_CONTROL */
 261
 262     case 'n':
 263       if (interactive_shell)
 264         read_but_dont_execute = 0;
 265       break;
 266
 267     case 'p':
 268       if (on_or_off == FLAG_OFF)
 269         disable_priv_mode ();
 270       break;
 271
 272 #if defined (RESTRICTED_SHELL)
 273     case 'r':
 274       if (on_or_off == FLAG_ON)
 275         maybe_make_restricted (shell_name);
 276       break;
 277 #endif
 278
 279     }
 280
 281   return (old_value);
 282 }
 283
 284 /* Return a string which is the names of all the currently
 285    set shell flags. */
 286 char *
 287 which_set_flags ()
 288 {
 289   char *temp;
 290   int i, string_index;
 291
 292   temp = (char *)xmalloc (1 + NUM_SHELL_FLAGS + read_from_stdin + want_pending_command);
 293   for (i = string_index = 0; shell_flags[i].name; i++)
 294     if (*(shell_flags[i].value))
 295       temp[string_index++] = shell_flags[i].name;
 296
 297   if (want_pending_command)
 298     temp[string_index++] = 'c';
 299   if (read_from_stdin)
 300     temp[string_index++] = 's';
 301
 302   temp[string_index] = '\0';
 303   return (temp);
 304 }
 305
 306 void
 307 reset_shell_flags ()
 308 {
 309   mark_modified_vars = exit_immediately_on_error = disallow_filename_globbing = 0;
 310   place_keywords_in_env = read_but_dont_execute = just_one_command = 0;
 311   noclobber = unbound_vars_is_error = echo_input_at_read = 0;
 312   echo_command_at_execute = jobs_m_flag = forced_interactive = 0;
 313   no_symbolic_links = no_invisible_vars = privileged_mode = 0;
 314
 315   hashing_enabled = interactive_comments = 1;
 316
 317 #if defined (JOB_CONTROL)
 318   asynchronous_notification = 0;
 319 #endif
 320
 321 #if defined (BANG_HISTORY)
 322   history_expansion = 1;
 323 #endif
 324
 325 #if defined (BRACE_EXPANSION)
 326   brace_expansion = 1;
 327 #endif
 328
 329 #if defined (RESTRICTED_SHELL)
 330   restricted = 0;
 331 #endif
 332 }
 333
 334 void
 335 initialize_flags ()
 336 {
 337   register int i;
 338
 339   for (i = 0; shell_flags[i].name; i++)
 340     optflags[i+1] = shell_flags[i].name;
 341   optflags[++i] = 'o';
 342   optflags[++i] = ';';
 343   optflags[i+1] = '\0';
 344 }