command.h

   1 /* command.h -- The structures used internally to represent commands, and
   2    the extern declarations of the functions used to create them. */
   3
   4 /* Copyright (C) 1993-2005 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 #if !defined (_COMMAND_H_)
  23 #define _COMMAND_H_
  24
  25 #include "stdc.h"
  26
  27 /* Instructions describing what kind of thing to do for a redirection. */
  28 enum r_instruction {
  29   r_output_direction, r_input_direction, r_inputa_direction,
  30   r_appending_to, r_reading_until, r_reading_string,
  31   r_duplicating_input, r_duplicating_output, r_deblank_reading_until,
  32   r_close_this, r_err_and_out, r_input_output, r_output_force,
  33   r_duplicating_input_word, r_duplicating_output_word,
  34   r_move_input, r_move_output, r_move_input_word, r_move_output_word
  35 };
  36
  37 /* Redirection errors. */
  38 #define AMBIGUOUS_REDIRECT  -1
  39 #define NOCLOBBER_REDIRECT  -2
  40 #define RESTRICTED_REDIRECT -3  /* can only happen in restricted shells. */
  41 #define HEREDOC_REDIRECT    -4  /* here-doc temp file can't be created */
  42
  43 #define CLOBBERING_REDIRECT(ri) \
  44   (ri == r_output_direction || ri == r_err_and_out)
  45
  46 #define OUTPUT_REDIRECT(ri) \
  47   (ri == r_output_direction || ri == r_input_output || ri == r_err_and_out)
  48
  49 #define INPUT_REDIRECT(ri) \
  50   (ri == r_input_direction || ri == r_inputa_direction || ri == r_input_output)
  51
  52 #define WRITE_REDIRECT(ri) \
  53   (ri == r_output_direction || \
  54         ri == r_input_output || \
  55         ri == r_err_and_out || \
  56         ri == r_appending_to || \
  57         ri == r_output_force)
  58
  59 /* redirection needs translation */
  60 #define TRANSLATE_REDIRECT(ri) \
  61   (ri == r_duplicating_input_word || ri == r_duplicating_output_word || \
  62    ri == r_move_input_word || ri == r_move_output_word)
  63
  64 /* Command Types: */
  65 enum command_type { cm_for, cm_case, cm_while, cm_if, cm_simple, cm_select,
  66                     cm_connection, cm_function_def, cm_until, cm_group,
  67                     cm_arith, cm_cond, cm_arith_for, cm_subshell };
  68
  69 /* Possible values for the `flags' field of a WORD_DESC. */
  70 #define W_HASDOLLAR     0x00001 /* Dollar sign present. */
  71 #define W_QUOTED        0x00002 /* Some form of quote character is present. */
  72 #define W_ASSIGNMENT    0x00004 /* This word is a variable assignment. */
  73 #define W_GLOBEXP       0x00008 /* This word is the result of a glob expansion. */
  74 #define W_NOSPLIT       0x00010 /* Do not perform word splitting on this word. */
  75 #define W_NOGLOB        0x00020 /* Do not perform globbing on this word. */
  76 #define W_NOSPLIT2      0x00040 /* Don't split word except for $@ expansion. */
  77 #define W_TILDEEXP      0x00080 /* Tilde expand this assignment word */
  78 #define W_DOLLARAT      0x00100 /* $@ and its special handling */
  79 #define W_DOLLARSTAR    0x00200 /* $* and its special handling */
  80 #define W_NOCOMSUB      0x00400 /* Don't perform command substitution on this word */
  81 #define W_ASSIGNRHS     0x00800 /* Word is rhs of an assignment statement */
  82 #define W_NOTILDE       0x01000 /* Don't perform tilde expansion on this word */
  83 #define W_ITILDE        0x02000 /* Internal flag for word expansion */
  84 #define W_NOEXPAND      0x04000 /* Don't expand at all -- do quote removal */
  85 #define W_COMPASSIGN    0x08000 /* Compound assignment */
  86 #define W_ASSNBLTIN     0x10000 /* word is a builtin command that takes assignments */
  87 #define W_ASSIGNARG     0x20000 /* word is assignment argument to command */
  88 #define W_HASQUOTEDNULL 0x40000 /* word contains a quoted null character */
  89 #define W_DQUOTE        0x80000 /* word should be treated as if double-quoted */
  90
  91 /* Possible values for subshell_environment */
  92 #define SUBSHELL_ASYNC  0x01    /* subshell caused by `command &' */
  93 #define SUBSHELL_PAREN  0x02    /* subshell caused by ( ... ) */
  94 #define SUBSHELL_COMSUB 0x04    /* subshell caused by `command` or $(command) */
  95 #define SUBSHELL_FORK   0x08    /* subshell caused by executing a disk command */
  96 #define SUBSHELL_PIPE   0x10    /* subshell from a pipeline element */
  97
  98 /* A structure which represents a word. */
  99 typedef struct word_desc {
 100   char *word;           /* Zero terminated string. */
 101   int flags;            /* Flags associated with this word. */
 102 } WORD_DESC;
 103
 104 /* A linked list of words. */
 105 typedef struct word_list {
 106   struct word_list *next;
 107   WORD_DESC *word;
 108 } WORD_LIST;
 109
 110
 111 /* **************************************************************** */
 112 /*                                                                  */
 113 /*                      Shell Command Structs                       */
 114 /*                                                                  */
 115 /* **************************************************************** */
 116
 117 /* What a redirection descriptor looks like.  If the redirection instruction
 118    is ri_duplicating_input or ri_duplicating_output, use DEST, otherwise
 119    use the file in FILENAME.  Out-of-range descriptors are identified by a
 120    negative DEST. */
 121
 122 typedef union {
 123   int dest;                     /* Place to redirect REDIRECTOR to, or ... */
 124   WORD_DESC *filename;          /* filename to redirect to. */
 125 } REDIRECTEE;
 126
 127 /* Structure describing a redirection.  If REDIRECTOR is negative, the parser
 128    (or translator in redir.c) encountered an out-of-range file descriptor. */
 129 typedef struct redirect {
 130   struct redirect *next;        /* Next element, or NULL. */
 131   int redirector;               /* Descriptor to be redirected. */
 132   int flags;                    /* Flag value for `open'. */
 133   enum r_instruction  instruction; /* What to do with the information. */
 134   REDIRECTEE redirectee;        /* File descriptor or filename */
 135   char *here_doc_eof;           /* The word that appeared in <<foo. */
 136 } REDIRECT;
 137
 138 /* An element used in parsing.  A single word or a single redirection.
 139    This is an ephemeral construct. */
 140 typedef struct element {
 141   WORD_DESC *word;
 142   REDIRECT *redirect;
 143 } ELEMENT;
 144
 145 /* Possible values for command->flags. */
 146 #define CMD_WANT_SUBSHELL  0x01 /* User wants a subshell: ( command ) */
 147 #define CMD_FORCE_SUBSHELL 0x02 /* Shell needs to force a subshell. */
 148 #define CMD_INVERT_RETURN  0x04 /* Invert the exit value. */
 149 #define CMD_IGNORE_RETURN  0x08 /* Ignore the exit value.  For set -e. */
 150 #define CMD_NO_FUNCTIONS   0x10 /* Ignore functions during command lookup. */
 151 #define CMD_INHIBIT_EXPANSION 0x20 /* Do not expand the command words. */
 152 #define CMD_NO_FORK        0x40 /* Don't fork; just call execve */
 153 #define CMD_TIME_PIPELINE  0x80 /* Time a pipeline */
 154 #define CMD_TIME_POSIX     0x100 /* time -p; use POSIX.2 time output spec. */
 155 #define CMD_AMPERSAND      0x200 /* command & */
 156 #define CMD_STDIN_REDIR    0x400 /* async command needs implicit </dev/null */
 157 #define CMD_COMMAND_BUILTIN 0x0800 /* command executed by `command' builtin */
 158
 159 /* What a command looks like. */
 160 typedef struct command {
 161   enum command_type type;       /* FOR CASE WHILE IF CONNECTION or SIMPLE. */
 162   int flags;                    /* Flags controlling execution environment. */
 163   int line;                     /* line number the command starts on */
 164   REDIRECT *redirects;          /* Special redirects for FOR CASE, etc. */
 165   union {
 166     struct for_com *For;
 167     struct case_com *Case;
 168     struct while_com *While;
 169     struct if_com *If;
 170     struct connection *Connection;
 171     struct simple_com *Simple;
 172     struct function_def *Function_def;
 173     struct group_com *Group;
 174 #if defined (SELECT_COMMAND)
 175     struct select_com *Select;
 176 #endif
 177 #if defined (DPAREN_ARITHMETIC)
 178     struct arith_com *Arith;
 179 #endif
 180 #if defined (COND_COMMAND)
 181     struct cond_com *Cond;
 182 #endif
 183 #if defined (ARITH_FOR_COMMAND)
 184     struct arith_for_com *ArithFor;
 185 #endif
 186     struct subshell_com *Subshell;
 187   } value;
 188 } COMMAND;
 189
 190 /* Structure used to represent the CONNECTION type. */
 191 typedef struct connection {
 192   int ignore;                   /* Unused; simplifies make_command (). */
 193   COMMAND *first;               /* Pointer to the first command. */
 194   COMMAND *second;              /* Pointer to the second command. */
 195   int connector;                /* What separates this command from others. */
 196 } CONNECTION;
 197
 198 /* Structures used to represent the CASE command. */
 199
 200 /* Pattern/action structure for CASE_COM. */
 201 typedef struct pattern_list {
 202   struct pattern_list *next;    /* Clause to try in case this one failed. */
 203   WORD_LIST *patterns;          /* Linked list of patterns to test. */
 204   COMMAND *action;              /* Thing to execute if a pattern matches. */
 205   int flags;
 206 } PATTERN_LIST;
 207
 208 /* The CASE command. */
 209 typedef struct case_com {
 210   int flags;                    /* See description of CMD flags. */
 211   int line;                     /* line number the `case' keyword appears on */
 212   WORD_DESC *word;              /* The thing to test. */
 213   PATTERN_LIST *clauses;        /* The clauses to test against, or NULL. */
 214 } CASE_COM;
 215
 216 /* FOR command. */
 217 typedef struct for_com {
 218   int flags;            /* See description of CMD flags. */
 219   int line;             /* line number the `for' keyword appears on */
 220   WORD_DESC *name;      /* The variable name to get mapped over. */
 221   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 222   COMMAND *action;      /* The action to execute.
 223                            During execution, NAME is bound to successive
 224                            members of MAP_LIST. */
 225 } FOR_COM;
 226
 227 #if defined (ARITH_FOR_COMMAND)
 228 typedef struct arith_for_com {
 229   int flags;
 230   int line;     /* generally used for error messages */
 231   WORD_LIST *init;
 232   WORD_LIST *test;
 233   WORD_LIST *step;
 234   COMMAND *action;
 235 } ARITH_FOR_COM;
 236 #endif
 237
 238 #if defined (SELECT_COMMAND)
 239 /* KSH SELECT command. */
 240 typedef struct select_com {
 241   int flags;            /* See description of CMD flags. */
 242   int line;             /* line number the `select' keyword appears on */
 243   WORD_DESC *name;      /* The variable name to get mapped over. */
 244   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 245   COMMAND *action;      /* The action to execute.
 246                            During execution, NAME is bound to the member of
 247                            MAP_LIST chosen by the user. */
 248 } SELECT_COM;
 249 #endif /* SELECT_COMMAND */
 250
 251 /* IF command. */
 252 typedef struct if_com {
 253   int flags;                    /* See description of CMD flags. */
 254   COMMAND *test;                /* Thing to test. */
 255   COMMAND *true_case;           /* What to do if the test returned non-zero. */
 256   COMMAND *false_case;          /* What to do if the test returned zero. */
 257 } IF_COM;
 258
 259 /* WHILE command. */
 260 typedef struct while_com {
 261   int flags;                    /* See description of CMD flags. */
 262   COMMAND *test;                /* Thing to test. */
 263   COMMAND *action;              /* Thing to do while test is non-zero. */
 264 } WHILE_COM;
 265
 266 #if defined (DPAREN_ARITHMETIC)
 267 /* The arithmetic evaluation command, ((...)).  Just a set of flags and
 268    a WORD_LIST, of which the first element is the only one used, for the
 269    time being. */
 270 typedef struct arith_com {
 271   int flags;
 272   int line;
 273   WORD_LIST *exp;
 274 } ARITH_COM;
 275 #endif /* DPAREN_ARITHMETIC */
 276
 277 /* The conditional command, [[...]].  This is a binary tree -- we slippped
 278    a recursive-descent parser into the YACC grammar to parse it. */
 279 #define COND_AND        1
 280 #define COND_OR         2
 281 #define COND_UNARY      3
 282 #define COND_BINARY     4
 283 #define COND_TERM       5
 284 #define COND_EXPR       6
 285
 286 typedef struct cond_com {
 287   int flags;
 288   int line;
 289   int type;
 290   WORD_DESC *op;
 291   struct cond_com *left, *right;
 292 } COND_COM;
 293
 294 /* The "simple" command.  Just a collection of words and redirects. */
 295 typedef struct simple_com {
 296   int flags;                    /* See description of CMD flags. */
 297   int line;                     /* line number the command starts on */
 298   WORD_LIST *words;             /* The program name, the arguments,
 299                                    variable assignments, etc. */
 300   REDIRECT *redirects;          /* Redirections to perform. */
 301 } SIMPLE_COM;
 302
 303 /* The "function definition" command. */
 304 typedef struct function_def {
 305   int flags;                    /* See description of CMD flags. */
 306   int line;                     /* Line number the function def starts on. */
 307   WORD_DESC *name;              /* The name of the function. */
 308   COMMAND *command;             /* The parsed execution tree. */
 309   char *source_file;            /* file in which function was defined, if any */
 310 } FUNCTION_DEF;
 311
 312 /* A command that is `grouped' allows pipes and redirections to affect all
 313    commands in the group. */
 314 typedef struct group_com {
 315   int ignore;                   /* See description of CMD flags. */
 316   COMMAND *command;
 317 } GROUP_COM;
 318
 319 typedef struct subshell_com {
 320   int flags;
 321   COMMAND *command;
 322 } SUBSHELL_COM;
 323
 324 extern COMMAND *global_command;
 325
 326 /* Possible command errors */
 327 #define CMDERR_DEFAULT  0
 328 #define CMDERR_BADTYPE  1
 329 #define CMDERR_BADCONN  2
 330 #define CMDERR_BADJUMP  3
 331
 332 #define CMDERR_LAST     3
 333
 334 /* Forward declarations of functions declared in copy_cmd.c. */
 335
 336 extern FUNCTION_DEF *copy_function_def_contents __P((FUNCTION_DEF *, FUNCTION_DEF *));
 337 extern FUNCTION_DEF *copy_function_def __P((FUNCTION_DEF *));
 338
 339 extern WORD_DESC *copy_word __P((WORD_DESC *));
 340 extern WORD_LIST *copy_word_list __P((WORD_LIST *));
 341 extern REDIRECT *copy_redirect __P((REDIRECT *));
 342 extern REDIRECT *copy_redirects __P((REDIRECT *));
 343 extern COMMAND *copy_command __P((COMMAND *));
 344
 345 #endif /* _COMMAND_H_ */