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, 675 Mass Ave, Cambridge, MA 02139, 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_duplicating_input,
  31   r_duplicating_output, r_deblank_reading_until, r_close_this,
  32   r_err_and_out, r_input_output, r_output_force,
  33   r_duplicating_input_word, r_duplicating_output_word
  34 };
  35
  36 /* Redirection errors. */
  37 #define AMBIGUOUS_REDIRECT  -1
  38 #define NOCLOBBER_REDIRECT  -2
  39 #define RESTRICTED_REDIRECT -3  /* can only happen in restricted shells. */
  40 #define HEREDOC_REDIRECT    -4  /* here-doc temp file can't be created */
  41
  42 #define OUTPUT_REDIRECT(ri) \
  43   (ri == r_output_direction || ri == r_input_output || ri == r_err_and_out)
  44
  45 #define INPUT_REDIRECT(ri) \
  46   (ri == r_input_direction || ri == r_inputa_direction || ri == r_input_output)
  47
  48 #define WRITE_REDIRECT(ri) \
  49   (ri == r_output_direction || \
  50         ri == r_input_output || \
  51         ri == r_err_and_out || \
  52         ri == r_appending_to || \
  53         ri == r_output_force)
  54
  55 /* Command Types: */
  56 enum command_type { cm_for, cm_case, cm_while, cm_if, cm_simple, cm_select,
  57                     cm_connection, cm_function_def, cm_until, cm_group,
  58                     cm_arith, cm_cond };
  59
  60 /* Possible values for the `flags' field of a WORD_DESC. */
  61 #define W_HASDOLLAR     0x01    /* Dollar sign present. */
  62 #define W_QUOTED        0x02    /* Some form of quote character is present. */
  63 #define W_ASSIGNMENT    0x04    /* This word is a variable assignment. */
  64 #define W_GLOBEXP       0x08    /* This word is the result of a glob expansion. */
  65 #define W_NOSPLIT       0x10    /* Do not perform word splitting on this word. */
  66
  67 /* Possible values for subshell_environment */
  68 #define SUBSHELL_ASYNC  0x01    /* subshell caused by `command &' */
  69 #define SUBSHELL_PAREN  0x02    /* subshell caused by ( ... ) */
  70 #define SUBSHELL_COMSUB 0x04    /* subshell caused by `command` or $(command) */
  71 #define SUBSHELL_FORK   0x08    /* subshell caused by executing a disk command */
  72
  73 /* A structure which represents a word. */
  74 typedef struct word_desc {
  75   char *word;           /* Zero terminated string. */
  76   int flags;            /* Flags associated with this word. */
  77 } WORD_DESC;
  78
  79 /* A linked list of words. */
  80 typedef struct word_list {
  81   struct word_list *next;
  82   WORD_DESC *word;
  83 } WORD_LIST;
  84
  85
  86 /* **************************************************************** */
  87 /*                                                                  */
  88 /*                      Shell Command Structs                       */
  89 /*                                                                  */
  90 /* **************************************************************** */
  91
  92 /* What a redirection descriptor looks like.  If FLAGS is IS_DESCRIPTOR,
  93    then we use REDIRECTEE.DEST, else we use the file specified. */
  94
  95 typedef union {
  96   long dest;                    /* Place to redirect REDIRECTOR to, or ... */
  97   WORD_DESC *filename;          /* filename to redirect to. */
  98 } REDIRECTEE;
  99
 100 typedef struct redirect {
 101   struct redirect *next;        /* Next element, or NULL. */
 102   int redirector;               /* Descriptor to be redirected. */
 103   int flags;                    /* Flag value for `open'. */
 104   enum r_instruction  instruction; /* What to do with the information. */
 105   REDIRECTEE redirectee;        /* File descriptor or filename */
 106   char *here_doc_eof;           /* The word that appeared in <<foo. */
 107 } REDIRECT;
 108
 109 /* An element used in parsing.  A single word or a single redirection.
 110    This is an ephemeral construct. */
 111 typedef struct element {
 112   WORD_DESC *word;
 113   REDIRECT *redirect;
 114 } ELEMENT;
 115
 116 /* Possible values for command->flags. */
 117 #define CMD_WANT_SUBSHELL  0x01 /* User wants a subshell: ( command ) */
 118 #define CMD_FORCE_SUBSHELL 0x02 /* Shell needs to force a subshell. */
 119 #define CMD_INVERT_RETURN  0x04 /* Invert the exit value. */
 120 #define CMD_IGNORE_RETURN  0x08 /* Ignore the exit value.  For set -e. */
 121 #define CMD_NO_FUNCTIONS   0x10 /* Ignore functions during command lookup. */
 122 #define CMD_INHIBIT_EXPANSION 0x20 /* Do not expand the command words. */
 123 #define CMD_NO_FORK        0x40 /* Don't fork; just call execve */
 124 #define CMD_TIME_PIPELINE  0x80 /* Time a pipeline */
 125 #define CMD_TIME_POSIX     0x100 /* time -p; use POSIX.2 time output spec. */
 126 #define CMD_AMPERSAND      0x200 /* command & */
 127 #define CMD_STDIN_REDIR    0x400 /* async command needs implicit </dev/null */
 128
 129 /* What a command looks like. */
 130 typedef struct command {
 131   enum command_type type;       /* FOR CASE WHILE IF CONNECTION or SIMPLE. */
 132   int flags;                    /* Flags controlling execution environment. */
 133   int line;                     /* line number the command starts on */
 134   REDIRECT *redirects;          /* Special redirects for FOR CASE, etc. */
 135   union {
 136     struct for_com *For;
 137     struct case_com *Case;
 138     struct while_com *While;
 139     struct if_com *If;
 140     struct connection *Connection;
 141     struct simple_com *Simple;
 142     struct function_def *Function_def;
 143     struct group_com *Group;
 144 #if defined (SELECT_COMMAND)
 145     struct select_com *Select;
 146 #endif
 147 #if defined (DPAREN_ARITHMETIC)
 148     struct arith_com *Arith;
 149 #endif
 150 #if defined (COND_COMMAND)
 151     struct cond_com *Cond;
 152 #endif
 153   } value;
 154 } COMMAND;
 155
 156 /* Structure used to represent the CONNECTION type. */
 157 typedef struct connection {
 158   int ignore;                   /* Unused; simplifies make_command (). */
 159   COMMAND *first;               /* Pointer to the first command. */
 160   COMMAND *second;              /* Pointer to the second command. */
 161   int connector;                /* What separates this command from others. */
 162 } CONNECTION;
 163
 164 /* Structures used to represent the CASE command. */
 165
 166 /* Pattern/action structure for CASE_COM. */
 167 typedef struct pattern_list {
 168   struct pattern_list *next;    /* Clause to try in case this one failed. */
 169   WORD_LIST *patterns;          /* Linked list of patterns to test. */
 170   COMMAND *action;              /* Thing to execute if a pattern matches. */
 171 } PATTERN_LIST;
 172
 173 /* The CASE command. */
 174 typedef struct case_com {
 175   int flags;                    /* See description of CMD flags. */
 176   WORD_DESC *word;              /* The thing to test. */
 177   PATTERN_LIST *clauses;        /* The clauses to test against, or NULL. */
 178 } CASE_COM;
 179
 180 /* FOR command. */
 181 typedef struct for_com {
 182   int flags;            /* See description of CMD flags. */
 183   WORD_DESC *name;      /* The variable name to get mapped over. */
 184   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 185   COMMAND *action;      /* The action to execute.
 186                            During execution, NAME is bound to successive
 187                            members of MAP_LIST. */
 188 } FOR_COM;
 189
 190 #if defined (SELECT_COMMAND)
 191 /* KSH SELECT command. */
 192 typedef struct select_com {
 193   int flags;            /* See description of CMD flags. */
 194   WORD_DESC *name;      /* The variable name to get mapped over. */
 195   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 196   COMMAND *action;      /* The action to execute.
 197                            During execution, NAME is bound to the member of
 198                            MAP_LIST chosen by the user. */
 199 } SELECT_COM;
 200 #endif /* SELECT_COMMAND */
 201
 202 /* IF command. */
 203 typedef struct if_com {
 204   int flags;                    /* See description of CMD flags. */
 205   COMMAND *test;                /* Thing to test. */
 206   COMMAND *true_case;           /* What to do if the test returned non-zero. */
 207   COMMAND *false_case;          /* What to do if the test returned zero. */
 208 } IF_COM;
 209
 210 /* WHILE command. */
 211 typedef struct while_com {
 212   int flags;                    /* See description of CMD flags. */
 213   COMMAND *test;                /* Thing to test. */
 214   COMMAND *action;              /* Thing to do while test is non-zero. */
 215 } WHILE_COM;
 216
 217 #if defined (DPAREN_ARITHMETIC)
 218 /* The arithmetic evaluation command, ((...)).  Just a set of flags and
 219    a WORD_LIST, of which the first element is the only one used, for the
 220    time being. */
 221 typedef struct arith_com {
 222   int flags;
 223   WORD_LIST *exp;
 224   int line;
 225 } ARITH_COM;
 226 #endif /* DPAREN_ARITHMETIC */
 227
 228 /* The conditional command, [[...]].  This is a binary tree -- we slippped
 229    a recursive-descent parser into the YACC grammar to parse it. */
 230 #define COND_AND        1
 231 #define COND_OR         2
 232 #define COND_UNARY      3
 233 #define COND_BINARY     4
 234 #define COND_TERM       5
 235 #define COND_EXPR       6
 236
 237 typedef struct cond_com {
 238   int flags;
 239   int line;
 240   int type;
 241   WORD_DESC *op;
 242   struct cond_com *left, *right;
 243 } COND_COM;
 244
 245 /* The "simple" command.  Just a collection of words and redirects. */
 246 typedef struct simple_com {
 247   int flags;                    /* See description of CMD flags. */
 248   WORD_LIST *words;             /* The program name, the arguments,
 249                                    variable assignments, etc. */
 250   REDIRECT *redirects;          /* Redirections to perform. */
 251   int line;                     /* line number the command starts on */
 252 } SIMPLE_COM;
 253
 254 /* The "function definition" command. */
 255 typedef struct function_def {
 256   int flags;                    /* See description of CMD flags. */
 257   WORD_DESC *name;              /* The name of the function. */
 258   COMMAND *command;             /* The parsed execution tree. */
 259   int line;                     /* Line number the function def starts on. */
 260 } FUNCTION_DEF;
 261
 262 /* A command that is `grouped' allows pipes and redirections to affect all
 263    commands in the group. */
 264 typedef struct group_com {
 265   int ignore;                   /* See description of CMD flags. */
 266   COMMAND *command;
 267 } GROUP_COM;
 268
 269 extern COMMAND *global_command;
 270
 271 /* Forward declarations of functions declared in copy_cmd.c. */
 272
 273 extern WORD_DESC *copy_word __P((WORD_DESC *));
 274 extern WORD_LIST *copy_word_list __P((WORD_LIST *));
 275 extern REDIRECT *copy_redirect __P((REDIRECT *));
 276 extern REDIRECT *copy_redirects __P((REDIRECT *));
 277 extern COMMAND *copy_command __P((COMMAND *));
 278
 279 #endif /* _COMMAND_H_ */