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 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     0x01    /* Dollar sign present. */
  71 #define W_QUOTED        0x02    /* Some form of quote character is present. */
  72 #define W_ASSIGNMENT    0x04    /* This word is a variable assignment. */
  73 #define W_GLOBEXP       0x08    /* This word is the result of a glob expansion. */
  74 #define W_NOSPLIT       0x10    /* Do not perform word splitting on this word. */
  75 #define W_NOGLOB        0x20    /* Do not perform globbing on this word. */
  76 #define W_NOSPLIT2      0x40    /* Don't split word except for $@ expansion. */
  77 #define W_TILDEEXP      0x80    /* Tilde expand this assignment word */
  78
  79 /* Possible values for subshell_environment */
  80 #define SUBSHELL_ASYNC  0x01    /* subshell caused by `command &' */
  81 #define SUBSHELL_PAREN  0x02    /* subshell caused by ( ... ) */
  82 #define SUBSHELL_COMSUB 0x04    /* subshell caused by `command` or $(command) */
  83 #define SUBSHELL_FORK   0x08    /* subshell caused by executing a disk command */
  84 #define SUBSHELL_PIPE   0x10    /* subshell from a pipeline element */
  85
  86 /* A structure which represents a word. */
  87 typedef struct word_desc {
  88   char *word;           /* Zero terminated string. */
  89   int flags;            /* Flags associated with this word. */
  90 } WORD_DESC;
  91
  92 /* A linked list of words. */
  93 typedef struct word_list {
  94   struct word_list *next;
  95   WORD_DESC *word;
  96 } WORD_LIST;
  97
  98
  99 /* **************************************************************** */
 100 /*                                                                  */
 101 /*                      Shell Command Structs                       */
 102 /*                                                                  */
 103 /* **************************************************************** */
 104
 105 /* What a redirection descriptor looks like.  If the redirection instruction
 106    is ri_duplicating_input or ri_duplicating_output, use DEST, otherwise
 107    use the file in FILENAME.  Out-of-range descriptors are identified by a
 108    negative DEST. */
 109
 110 typedef union {
 111   int dest;                     /* Place to redirect REDIRECTOR to, or ... */
 112   WORD_DESC *filename;          /* filename to redirect to. */
 113 } REDIRECTEE;
 114
 115 /* Structure describing a redirection.  If REDIRECTOR is negative, the parser
 116    (or translator in redir.c) encountered an out-of-range file descriptor. */
 117 typedef struct redirect {
 118   struct redirect *next;        /* Next element, or NULL. */
 119   int redirector;               /* Descriptor to be redirected. */
 120   int flags;                    /* Flag value for `open'. */
 121   enum r_instruction  instruction; /* What to do with the information. */
 122   REDIRECTEE redirectee;        /* File descriptor or filename */
 123   char *here_doc_eof;           /* The word that appeared in <<foo. */
 124 } REDIRECT;
 125
 126 /* An element used in parsing.  A single word or a single redirection.
 127    This is an ephemeral construct. */
 128 typedef struct element {
 129   WORD_DESC *word;
 130   REDIRECT *redirect;
 131 } ELEMENT;
 132
 133 /* Possible values for command->flags. */
 134 #define CMD_WANT_SUBSHELL  0x01 /* User wants a subshell: ( command ) */
 135 #define CMD_FORCE_SUBSHELL 0x02 /* Shell needs to force a subshell. */
 136 #define CMD_INVERT_RETURN  0x04 /* Invert the exit value. */
 137 #define CMD_IGNORE_RETURN  0x08 /* Ignore the exit value.  For set -e. */
 138 #define CMD_NO_FUNCTIONS   0x10 /* Ignore functions during command lookup. */
 139 #define CMD_INHIBIT_EXPANSION 0x20 /* Do not expand the command words. */
 140 #define CMD_NO_FORK        0x40 /* Don't fork; just call execve */
 141 #define CMD_TIME_PIPELINE  0x80 /* Time a pipeline */
 142 #define CMD_TIME_POSIX     0x100 /* time -p; use POSIX.2 time output spec. */
 143 #define CMD_AMPERSAND      0x200 /* command & */
 144 #define CMD_STDIN_REDIR    0x400 /* async command needs implicit </dev/null */
 145 #define CMD_COMMAND_BUILTIN 0x0800 /* command executed by `command' builtin */
 146
 147 /* What a command looks like. */
 148 typedef struct command {
 149   enum command_type type;       /* FOR CASE WHILE IF CONNECTION or SIMPLE. */
 150   int flags;                    /* Flags controlling execution environment. */
 151   int line;                     /* line number the command starts on */
 152   REDIRECT *redirects;          /* Special redirects for FOR CASE, etc. */
 153   union {
 154     struct for_com *For;
 155     struct case_com *Case;
 156     struct while_com *While;
 157     struct if_com *If;
 158     struct connection *Connection;
 159     struct simple_com *Simple;
 160     struct function_def *Function_def;
 161     struct group_com *Group;
 162 #if defined (SELECT_COMMAND)
 163     struct select_com *Select;
 164 #endif
 165 #if defined (DPAREN_ARITHMETIC)
 166     struct arith_com *Arith;
 167 #endif
 168 #if defined (COND_COMMAND)
 169     struct cond_com *Cond;
 170 #endif
 171 #if defined (ARITH_FOR_COMMAND)
 172     struct arith_for_com *ArithFor;
 173 #endif
 174     struct subshell_com *Subshell;
 175   } value;
 176 } COMMAND;
 177
 178 /* Structure used to represent the CONNECTION type. */
 179 typedef struct connection {
 180   int ignore;                   /* Unused; simplifies make_command (). */
 181   COMMAND *first;               /* Pointer to the first command. */
 182   COMMAND *second;              /* Pointer to the second command. */
 183   int connector;                /* What separates this command from others. */
 184 } CONNECTION;
 185
 186 /* Structures used to represent the CASE command. */
 187
 188 /* Pattern/action structure for CASE_COM. */
 189 typedef struct pattern_list {
 190   struct pattern_list *next;    /* Clause to try in case this one failed. */
 191   WORD_LIST *patterns;          /* Linked list of patterns to test. */
 192   COMMAND *action;              /* Thing to execute if a pattern matches. */
 193 } PATTERN_LIST;
 194
 195 /* The CASE command. */
 196 typedef struct case_com {
 197   int flags;                    /* See description of CMD flags. */
 198   WORD_DESC *word;              /* The thing to test. */
 199   PATTERN_LIST *clauses;        /* The clauses to test against, or NULL. */
 200 } CASE_COM;
 201
 202 /* FOR command. */
 203 typedef struct for_com {
 204   int flags;            /* See description of CMD flags. */
 205   WORD_DESC *name;      /* The variable name to get mapped over. */
 206   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 207   COMMAND *action;      /* The action to execute.
 208                            During execution, NAME is bound to successive
 209                            members of MAP_LIST. */
 210 } FOR_COM;
 211
 212 #if defined (ARITH_FOR_COMMAND)
 213 typedef struct arith_for_com {
 214   int flags;
 215   int line;     /* generally used for error messages */
 216   WORD_LIST *init;
 217   WORD_LIST *test;
 218   WORD_LIST *step;
 219   COMMAND *action;
 220 } ARITH_FOR_COM;
 221 #endif
 222
 223 #if defined (SELECT_COMMAND)
 224 /* KSH SELECT command. */
 225 typedef struct select_com {
 226   int flags;            /* See description of CMD flags. */
 227   WORD_DESC *name;      /* The variable name to get mapped over. */
 228   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 229   COMMAND *action;      /* The action to execute.
 230                            During execution, NAME is bound to the member of
 231                            MAP_LIST chosen by the user. */
 232 } SELECT_COM;
 233 #endif /* SELECT_COMMAND */
 234
 235 /* IF command. */
 236 typedef struct if_com {
 237   int flags;                    /* See description of CMD flags. */
 238   COMMAND *test;                /* Thing to test. */
 239   COMMAND *true_case;           /* What to do if the test returned non-zero. */
 240   COMMAND *false_case;          /* What to do if the test returned zero. */
 241 } IF_COM;
 242
 243 /* WHILE command. */
 244 typedef struct while_com {
 245   int flags;                    /* See description of CMD flags. */
 246   COMMAND *test;                /* Thing to test. */
 247   COMMAND *action;              /* Thing to do while test is non-zero. */
 248 } WHILE_COM;
 249
 250 #if defined (DPAREN_ARITHMETIC)
 251 /* The arithmetic evaluation command, ((...)).  Just a set of flags and
 252    a WORD_LIST, of which the first element is the only one used, for the
 253    time being. */
 254 typedef struct arith_com {
 255   int flags;
 256   WORD_LIST *exp;
 257   int line;
 258 } ARITH_COM;
 259 #endif /* DPAREN_ARITHMETIC */
 260
 261 /* The conditional command, [[...]].  This is a binary tree -- we slippped
 262    a recursive-descent parser into the YACC grammar to parse it. */
 263 #define COND_AND        1
 264 #define COND_OR         2
 265 #define COND_UNARY      3
 266 #define COND_BINARY     4
 267 #define COND_TERM       5
 268 #define COND_EXPR       6
 269
 270 typedef struct cond_com {
 271   int flags;
 272   int line;
 273   int type;
 274   WORD_DESC *op;
 275   struct cond_com *left, *right;
 276 } COND_COM;
 277
 278 /* The "simple" command.  Just a collection of words and redirects. */
 279 typedef struct simple_com {
 280   int flags;                    /* See description of CMD flags. */
 281   WORD_LIST *words;             /* The program name, the arguments,
 282                                    variable assignments, etc. */
 283   REDIRECT *redirects;          /* Redirections to perform. */
 284   int line;                     /* line number the command starts on */
 285 } SIMPLE_COM;
 286
 287 /* The "function definition" command. */
 288 typedef struct function_def {
 289   int flags;                    /* See description of CMD flags. */
 290   WORD_DESC *name;              /* The name of the function. */
 291   COMMAND *command;             /* The parsed execution tree. */
 292   int line;                     /* Line number the function def starts on. */
 293 } FUNCTION_DEF;
 294
 295 /* A command that is `grouped' allows pipes and redirections to affect all
 296    commands in the group. */
 297 typedef struct group_com {
 298   int ignore;                   /* See description of CMD flags. */
 299   COMMAND *command;
 300 } GROUP_COM;
 301
 302 typedef struct subshell_com {
 303   int flags;
 304   COMMAND *command;
 305 } SUBSHELL_COM;
 306
 307 extern COMMAND *global_command;
 308
 309 /* Possible command errors */
 310 #define CMDERR_DEFAULT  0
 311 #define CMDERR_BADTYPE  1
 312 #define CMDERR_BADCONN  2
 313 #define CMDERR_BADJUMP  3
 314
 315 #define CMDERR_LAST     3
 316
 317 /* Forward declarations of functions declared in copy_cmd.c. */
 318
 319 extern WORD_DESC *copy_word __P((WORD_DESC *));
 320 extern WORD_LIST *copy_word_list __P((WORD_LIST *));
 321 extern REDIRECT *copy_redirect __P((REDIRECT *));
 322 extern REDIRECT *copy_redirects __P((REDIRECT *));
 323 extern COMMAND *copy_command __P((COMMAND *));
 324
 325 #endif /* _COMMAND_H_ */