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 extern int shell_initialized;
  44
  45 /* -c, -s invocation options -- not really flags, but they show up in $- */
  46 extern int want_pending_command, read_from_stdin;
  47
  48 /* **************************************************************** */
  49 /*                                                                  */
  50 /*                      The Standard Sh Flags.                      */
  51 /*                                                                  */
  52 /* **************************************************************** */
  53
  54 /* Non-zero means automatically mark variables which are modified or created
  55    as auto export variables. */
  56 int mark_modified_vars = 0;
  57
  58 /* Non-zero causes asynchronous job notification.  Otherwise, job state
  59    notification only takes place just before a primary prompt is printed. */
  60 int asynchronous_notification = 0;
  61
  62 /* Non-zero means exit immediately if a command exits with a non-zero
  63    exit status. */
  64 int exit_immediately_on_error = 0;
  65
  66 /* Non-zero means disable filename globbing. */
  67 int disallow_filename_globbing = 0;
  68
  69 /* Non-zero means that all keyword arguments are placed into the environment
  70    for a command, not just those that appear on the line before the command
  71    name. */
  72 int place_keywords_in_env = 0;
  73
  74 /* Non-zero means read commands, but don't execute them.  This is useful
  75    for debugging shell scripts that should do something hairy and possibly
  76    destructive. */
  77 int read_but_dont_execute = 0;
  78
  79 /* Non-zero means end of file is after one command. */
  80 int just_one_command = 0;
  81
  82 /* Non-zero means don't overwrite existing files while doing redirections. */
  83 int noclobber = 0;
  84
  85 /* Non-zero means trying to get the value of $i where $i is undefined
  86    causes an error, instead of a null substitution. */
  87 int unbound_vars_is_error = 0;
  88
  89 /* Non-zero means type out input lines after you read them. */
  90 int echo_input_at_read = 0;
  91
  92 /* Non-zero means type out the command definition after reading, but
  93    before executing. */
  94 int echo_command_at_execute = 0;
  95
  96 /* Non-zero means turn on the job control features. */
  97 int jobs_m_flag = 0;
  98
  99 /* Non-zero means this shell is interactive, even if running under a
 100    pipe. */
 101 int forced_interactive = 0;
 102
 103 /* By default, follow the symbolic links as if they were real directories
 104    while hacking the `cd' command.  This means that `cd ..' moves up in
 105    the string of symbolic links that make up the current directory, instead
 106    of the absolute directory.  The shell variable `nolinks' also controls
 107    this flag. */
 108 int no_symbolic_links = 0;
 109
 110 /* **************************************************************** */
 111 /*                                                                  */
 112 /*                   Non-Standard Flags Follow Here.                */
 113 /*                                                                  */
 114 /* **************************************************************** */
 115
 116 #if 0
 117 /* Non-zero means do lexical scoping in the body of a FOR command. */
 118 int lexical_scoping = 0;
 119 #endif
 120
 121 /* Non-zero means no such thing as invisible variables. */
 122 int no_invisible_vars = 0;
 123
 124 /* Non-zero means look up and remember command names in a hash table, */
 125 int hashing_enabled = 1;
 126
 127 #if defined (BANG_HISTORY)
 128 /* Non-zero means that we are doing history expansion.  The default.
 129    This means !22 gets the 22nd line of history. */
 130 int history_expansion = 1;
 131 #endif /* BANG_HISTORY */
 132
 133 /* Non-zero means that we allow comments to appear in interactive commands. */
 134 int interactive_comments = 1;
 135
 136 #if defined (RESTRICTED_SHELL)
 137 /* Non-zero means that this shell is `restricted'.  A restricted shell
 138    disallows: changing directories, command or path names containing `/',
 139    unsetting or resetting the values of $PATH and $SHELL, and any type of
 140    output redirection. */
 141 int restricted = 0;             /* currently restricted */
 142 int restricted_shell = 0;       /* shell was started in restricted mode. */
 143 #endif /* RESTRICTED_SHELL */
 144
 145 /* Non-zero means that this shell is running in `privileged' mode.  This
 146    is required if the shell is to run setuid.  If the `-p' option is
 147    not supplied at startup, and the real and effective uids or gids
 148    differ, disable_priv_mode is called to relinquish setuid status. */
 149 int privileged_mode = 0;
 150
 151 #if defined (BRACE_EXPANSION)
 152 /* Zero means to disable brace expansion: foo{a,b} -> fooa foob */
 153 int brace_expansion = 1;
 154 #endif
 155
 156 /* Non-zero means that shell functions inherit the DEBUG trap. */
 157 int function_trace_mode = 0;
 158
 159 /* Non-zero means that shell functions inherit the ERR trap. */
 160 int error_trace_mode = 0;
 161
 162 /* Non-zero means that the rightmost non-zero exit status in a pipeline
 163    is the exit status of the entire pipeline.  If each processes exits
 164    with a 0 status, the status of the pipeline is 0. */
 165 int pipefail_opt = 0;
 166
 167 /* **************************************************************** */
 168 /*                                                                  */
 169 /*                      The Flags ALIST.                            */
 170 /*                                                                  */
 171 /* **************************************************************** */
 172
 173 struct flags_alist shell_flags[] = {
 174   /* Standard sh flags. */
 175   { 'a', &mark_modified_vars },
 176 #if defined (JOB_CONTROL)
 177   { 'b', &asynchronous_notification },
 178 #endif /* JOB_CONTROL */
 179   { 'e', &exit_immediately_on_error },
 180   { 'f', &disallow_filename_globbing },
 181   { 'h', &hashing_enabled },
 182   { 'i', &forced_interactive },
 183   { 'k', &place_keywords_in_env },
 184 #if defined (JOB_CONTROL)
 185   { 'm', &jobs_m_flag },
 186 #endif /* JOB_CONTROL */
 187   { 'n', &read_but_dont_execute },
 188   { 'p', &privileged_mode },
 189 #if defined (RESTRICTED_SHELL)
 190   { 'r', &restricted },
 191 #endif /* RESTRICTED_SHELL */
 192   { 't', &just_one_command },
 193   { 'u', &unbound_vars_is_error },
 194   { 'v', &echo_input_at_read },
 195   { 'x', &echo_command_at_execute },
 196
 197   /* New flags that control non-standard things. */
 198 #if 0
 199   { 'l', &lexical_scoping },
 200 #endif
 201 #if defined (BRACE_EXPANSION)
 202   { 'B', &brace_expansion },
 203 #endif
 204   { 'C', &noclobber },
 205   { 'E', &error_trace_mode },
 206 #if defined (BANG_HISTORY)
 207   { 'H', &history_expansion },
 208 #endif /* BANG_HISTORY */
 209   { 'I', &no_invisible_vars },
 210   { 'P', &no_symbolic_links },
 211   { 'T', &function_trace_mode },
 212   {0, (int *)NULL}
 213 };
 214
 215 #define NUM_SHELL_FLAGS (sizeof (shell_flags) / sizeof (struct flags_alist))
 216
 217 char optflags[NUM_SHELL_FLAGS+4] = { '+' };
 218
 219 int *
 220 find_flag (name)
 221      int name;
 222 {
 223   int i;
 224   for (i = 0; shell_flags[i].name; i++)
 225     {
 226       if (shell_flags[i].name == name)
 227         return (shell_flags[i].value);
 228     }
 229   return (FLAG_UNKNOWN);
 230 }
 231
 232 /* Change the state of a flag, and return it's original value, or return
 233    FLAG_ERROR if there is no flag FLAG.  ON_OR_OFF must be either
 234    FLAG_ON or FLAG_OFF. */
 235 int
 236 change_flag (flag, on_or_off)
 237   int flag;
 238   int on_or_off;
 239 {
 240   int *value, old_value;
 241
 242 #if defined (RESTRICTED_SHELL)
 243   /* Don't allow "set +r" in a shell which is `restricted'. */
 244   if (restricted && flag == 'r' && on_or_off == FLAG_OFF)
 245     return (FLAG_ERROR);
 246 #endif /* RESTRICTED_SHELL */
 247
 248   value = find_flag (flag);
 249
 250   if ((value == (int *)FLAG_UNKNOWN) || (on_or_off != FLAG_ON && on_or_off != FLAG_OFF))
 251     return (FLAG_ERROR);
 252
 253   old_value = *value;
 254
 255   *value = (on_or_off == FLAG_ON) ? 1 : 0;
 256
 257   /* Special cases for a few flags. */
 258   switch (flag)
 259     {
 260 #if defined (BANG_HISTORY)
 261     case 'H':
 262       if (on_or_off == FLAG_ON)
 263         bash_initialize_history ();
 264       break;
 265 #endif
 266
 267 #if defined (JOB_CONTROL)
 268     case 'm':
 269       set_job_control (on_or_off == FLAG_ON);
 270       break;
 271 #endif /* JOB_CONTROL */
 272
 273     case 'n':
 274       if (interactive_shell)
 275         read_but_dont_execute = 0;
 276       break;
 277
 278     case 'p':
 279       if (on_or_off == FLAG_OFF)
 280         disable_priv_mode ();
 281       break;
 282
 283 #if defined (RESTRICTED_SHELL)
 284     case 'r':
 285       if (on_or_off == FLAG_ON && shell_initialized)
 286         maybe_make_restricted (shell_name);
 287       break;
 288 #endif
 289
 290     }
 291
 292   return (old_value);
 293 }
 294
 295 /* Return a string which is the names of all the currently
 296    set shell flags. */
 297 char *
 298 which_set_flags ()
 299 {
 300   char *temp;
 301   int i, string_index;
 302
 303   temp = (char *)xmalloc (1 + NUM_SHELL_FLAGS + read_from_stdin + want_pending_command);
 304   for (i = string_index = 0; shell_flags[i].name; i++)
 305     if (*(shell_flags[i].value))
 306       temp[string_index++] = shell_flags[i].name;
 307
 308   if (want_pending_command)
 309     temp[string_index++] = 'c';
 310   if (read_from_stdin)
 311     temp[string_index++] = 's';
 312
 313   temp[string_index] = '\0';
 314   return (temp);
 315 }
 316
 317 void
 318 reset_shell_flags ()
 319 {
 320   mark_modified_vars = exit_immediately_on_error = disallow_filename_globbing = 0;
 321   place_keywords_in_env = read_but_dont_execute = just_one_command = 0;
 322   noclobber = unbound_vars_is_error = echo_input_at_read = 0;
 323   echo_command_at_execute = jobs_m_flag = forced_interactive = 0;
 324   no_symbolic_links = no_invisible_vars = privileged_mode = pipefail_opt = 0;
 325
 326   hashing_enabled = interactive_comments = 1;
 327
 328 #if defined (JOB_CONTROL)
 329   asynchronous_notification = 0;
 330 #endif
 331
 332 #if defined (BANG_HISTORY)
 333   history_expansion = 1;
 334 #endif
 335
 336 #if defined (BRACE_EXPANSION)
 337   brace_expansion = 1;
 338 #endif
 339
 340 #if defined (RESTRICTED_SHELL)
 341   restricted = 0;
 342 #endif
 343 }
 344
 345 void
 346 initialize_flags ()
 347 {
 348   register int i;
 349
 350   for (i = 0; shell_flags[i].name; i++)
 351     optflags[i+1] = shell_flags[i].name;
 352   optflags[++i] = 'o';
 353   optflags[++i] = ';';
 354   optflags[i+1] = '\0';
 355 }