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_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 CLOBBERING_REDIRECT(ri) \
  43   (ri == r_output_direction || ri == r_err_and_out)
  44
  45 #define OUTPUT_REDIRECT(ri) \
  46   (ri == r_output_direction || ri == r_input_output || ri == r_err_and_out)
  47
  48 #define INPUT_REDIRECT(ri) \
  49   (ri == r_input_direction || ri == r_inputa_direction || ri == r_input_output)
  50
  51 #define WRITE_REDIRECT(ri) \
  52   (ri == r_output_direction || \
  53         ri == r_input_output || \
  54         ri == r_err_and_out || \
  55         ri == r_appending_to || \
  56         ri == r_output_force)
  57
  58 /* Command Types: */
  59 enum command_type { cm_for, cm_case, cm_while, cm_if, cm_simple, cm_select,
  60                     cm_connection, cm_function_def, cm_until, cm_group,
  61                     cm_arith, cm_cond, cm_arith_for, cm_subshell };
  62
  63 /* Possible values for the `flags' field of a WORD_DESC. */
  64 #define W_HASDOLLAR     0x01    /* Dollar sign present. */
  65 #define W_QUOTED        0x02    /* Some form of quote character is present. */
  66 #define W_ASSIGNMENT    0x04    /* This word is a variable assignment. */
  67 #define W_GLOBEXP       0x08    /* This word is the result of a glob expansion. */
  68 #define W_NOSPLIT       0x10    /* Do not perform word splitting on this word. */
  69 #define W_NOGLOB        0x20    /* Do not perform globbing on this word. */
  70 #define W_NOSPLIT2      0x40    /* Don't split word except for $@ expansion. */
  71
  72 /* Possible values for subshell_environment */
  73 #define SUBSHELL_ASYNC  0x01    /* subshell caused by `command &' */
  74 #define SUBSHELL_PAREN  0x02    /* subshell caused by ( ... ) */
  75 #define SUBSHELL_COMSUB 0x04    /* subshell caused by `command` or $(command) */
  76 #define SUBSHELL_FORK   0x08    /* subshell caused by executing a disk command */
  77 #define SUBSHELL_PIPE   0x10    /* subshell from a pipeline element */
  78
  79 /* A structure which represents a word. */
  80 typedef struct word_desc {
  81   char *word;           /* Zero terminated string. */
  82   int flags;            /* Flags associated with this word. */
  83 } WORD_DESC;
  84
  85 /* A linked list of words. */
  86 typedef struct word_list {
  87   struct word_list *next;
  88   WORD_DESC *word;
  89 } WORD_LIST;
  90
  91
  92 /* **************************************************************** */
  93 /*                                                                  */
  94 /*                      Shell Command Structs                       */
  95 /*                                                                  */
  96 /* **************************************************************** */
  97
  98 /* What a redirection descriptor looks like.  If FLAGS is IS_DESCRIPTOR,
  99    then we use REDIRECTEE.DEST, else we use the file specified. */
 100
 101 typedef union {
 102   long dest;                    /* Place to redirect REDIRECTOR to, or ... */
 103   WORD_DESC *filename;          /* filename to redirect to. */
 104 } REDIRECTEE;
 105
 106 typedef struct redirect {
 107   struct redirect *next;        /* Next element, or NULL. */
 108   int redirector;               /* Descriptor to be redirected. */
 109   int flags;                    /* Flag value for `open'. */
 110   enum r_instruction  instruction; /* What to do with the information. */
 111   REDIRECTEE redirectee;        /* File descriptor or filename */
 112   char *here_doc_eof;           /* The word that appeared in <<foo. */
 113 } REDIRECT;
 114
 115 /* An element used in parsing.  A single word or a single redirection.
 116    This is an ephemeral construct. */
 117 typedef struct element {
 118   WORD_DESC *word;
 119   REDIRECT *redirect;
 120 } ELEMENT;
 121
 122 /* Possible values for command->flags. */
 123 #define CMD_WANT_SUBSHELL  0x01 /* User wants a subshell: ( command ) */
 124 #define CMD_FORCE_SUBSHELL 0x02 /* Shell needs to force a subshell. */
 125 #define CMD_INVERT_RETURN  0x04 /* Invert the exit value. */
 126 #define CMD_IGNORE_RETURN  0x08 /* Ignore the exit value.  For set -e. */
 127 #define CMD_NO_FUNCTIONS   0x10 /* Ignore functions during command lookup. */
 128 #define CMD_INHIBIT_EXPANSION 0x20 /* Do not expand the command words. */
 129 #define CMD_NO_FORK        0x40 /* Don't fork; just call execve */
 130 #define CMD_TIME_PIPELINE  0x80 /* Time a pipeline */
 131 #define CMD_TIME_POSIX     0x100 /* time -p; use POSIX.2 time output spec. */
 132 #define CMD_AMPERSAND      0x200 /* command & */
 133 #define CMD_STDIN_REDIR    0x400 /* async command needs implicit </dev/null */
 134
 135 /* What a command looks like. */
 136 typedef struct command {
 137   enum command_type type;       /* FOR CASE WHILE IF CONNECTION or SIMPLE. */
 138   int flags;                    /* Flags controlling execution environment. */
 139   int line;                     /* line number the command starts on */
 140   REDIRECT *redirects;          /* Special redirects for FOR CASE, etc. */
 141   union {
 142     struct for_com *For;
 143     struct case_com *Case;
 144     struct while_com *While;
 145     struct if_com *If;
 146     struct connection *Connection;
 147     struct simple_com *Simple;
 148     struct function_def *Function_def;
 149     struct group_com *Group;
 150 #if defined (SELECT_COMMAND)
 151     struct select_com *Select;
 152 #endif
 153 #if defined (DPAREN_ARITHMETIC)
 154     struct arith_com *Arith;
 155 #endif
 156 #if defined (COND_COMMAND)
 157     struct cond_com *Cond;
 158 #endif
 159 #if defined (ARITH_FOR_COMMAND)
 160     struct arith_for_com *ArithFor;
 161 #endif
 162     struct subshell_com *Subshell;
 163   } value;
 164 } COMMAND;
 165
 166 /* Structure used to represent the CONNECTION type. */
 167 typedef struct connection {
 168   int ignore;                   /* Unused; simplifies make_command (). */
 169   COMMAND *first;               /* Pointer to the first command. */
 170   COMMAND *second;              /* Pointer to the second command. */
 171   int connector;                /* What separates this command from others. */
 172 } CONNECTION;
 173
 174 /* Structures used to represent the CASE command. */
 175
 176 /* Pattern/action structure for CASE_COM. */
 177 typedef struct pattern_list {
 178   struct pattern_list *next;    /* Clause to try in case this one failed. */
 179   WORD_LIST *patterns;          /* Linked list of patterns to test. */
 180   COMMAND *action;              /* Thing to execute if a pattern matches. */
 181 } PATTERN_LIST;
 182
 183 /* The CASE command. */
 184 typedef struct case_com {
 185   int flags;                    /* See description of CMD flags. */
 186   WORD_DESC *word;              /* The thing to test. */
 187   PATTERN_LIST *clauses;        /* The clauses to test against, or NULL. */
 188 } CASE_COM;
 189
 190 /* FOR command. */
 191 typedef struct for_com {
 192   int flags;            /* See description of CMD flags. */
 193   WORD_DESC *name;      /* The variable name to get mapped over. */
 194   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 195   COMMAND *action;      /* The action to execute.
 196                            During execution, NAME is bound to successive
 197                            members of MAP_LIST. */
 198 } FOR_COM;
 199
 200 #if defined (ARITH_FOR_COMMAND)
 201 typedef struct arith_for_com {
 202   int flags;
 203   int line;     /* generally used for error messages */
 204   WORD_LIST *init;
 205   WORD_LIST *test;
 206   WORD_LIST *step;
 207   COMMAND *action;
 208 } ARITH_FOR_COM;
 209 #endif
 210
 211 #if defined (SELECT_COMMAND)
 212 /* KSH SELECT command. */
 213 typedef struct select_com {
 214   int flags;            /* See description of CMD flags. */
 215   WORD_DESC *name;      /* The variable name to get mapped over. */
 216   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 217   COMMAND *action;      /* The action to execute.
 218                            During execution, NAME is bound to the member of
 219                            MAP_LIST chosen by the user. */
 220 } SELECT_COM;
 221 #endif /* SELECT_COMMAND */
 222
 223 /* IF command. */
 224 typedef struct if_com {
 225   int flags;                    /* See description of CMD flags. */
 226   COMMAND *test;                /* Thing to test. */
 227   COMMAND *true_case;           /* What to do if the test returned non-zero. */
 228   COMMAND *false_case;          /* What to do if the test returned zero. */
 229 } IF_COM;
 230
 231 /* WHILE command. */
 232 typedef struct while_com {
 233   int flags;                    /* See description of CMD flags. */
 234   COMMAND *test;                /* Thing to test. */
 235   COMMAND *action;              /* Thing to do while test is non-zero. */
 236 } WHILE_COM;
 237
 238 #if defined (DPAREN_ARITHMETIC)
 239 /* The arithmetic evaluation command, ((...)).  Just a set of flags and
 240    a WORD_LIST, of which the first element is the only one used, for the
 241    time being. */
 242 typedef struct arith_com {
 243   int flags;
 244   WORD_LIST *exp;
 245   int line;
 246 } ARITH_COM;
 247 #endif /* DPAREN_ARITHMETIC */
 248
 249 /* The conditional command, [[...]].  This is a binary tree -- we slippped
 250    a recursive-descent parser into the YACC grammar to parse it. */
 251 #define COND_AND        1
 252 #define COND_OR         2
 253 #define COND_UNARY      3
 254 #define COND_BINARY     4
 255 #define COND_TERM       5
 256 #define COND_EXPR       6
 257
 258 typedef struct cond_com {
 259   int flags;
 260   int line;
 261   int type;
 262   WORD_DESC *op;
 263   struct cond_com *left, *right;
 264 } COND_COM;
 265
 266 /* The "simple" command.  Just a collection of words and redirects. */
 267 typedef struct simple_com {
 268   int flags;                    /* See description of CMD flags. */
 269   WORD_LIST *words;             /* The program name, the arguments,
 270                                    variable assignments, etc. */
 271   REDIRECT *redirects;          /* Redirections to perform. */
 272   int line;                     /* line number the command starts on */
 273 } SIMPLE_COM;
 274
 275 /* The "function definition" command. */
 276 typedef struct function_def {
 277   int flags;                    /* See description of CMD flags. */
 278   WORD_DESC *name;              /* The name of the function. */
 279   COMMAND *command;             /* The parsed execution tree. */
 280   int line;                     /* Line number the function def starts on. */
 281 } FUNCTION_DEF;
 282
 283 /* A command that is `grouped' allows pipes and redirections to affect all
 284    commands in the group. */
 285 typedef struct group_com {
 286   int ignore;                   /* See description of CMD flags. */
 287   COMMAND *command;
 288 } GROUP_COM;
 289
 290 typedef struct subshell_com {
 291   int flags;
 292   COMMAND *command;
 293 } SUBSHELL_COM;
 294
 295 extern COMMAND *global_command;
 296
 297 /* Possible command errors */
 298 #define CMDERR_DEFAULT  0
 299 #define CMDERR_BADTYPE  1
 300 #define CMDERR_BADCONN  2
 301 #define CMDERR_BADJUMP  3
 302
 303 #define CMDERR_LAST     3
 304
 305 /* Forward declarations of functions declared in copy_cmd.c. */
 306
 307 extern WORD_DESC *copy_word __P((WORD_DESC *));
 308 extern WORD_LIST *copy_word_list __P((WORD_LIST *));
 309 extern REDIRECT *copy_redirect __P((REDIRECT *));
 310 extern REDIRECT *copy_redirects __P((REDIRECT *));
 311 extern COMMAND *copy_command __P((COMMAND *));
 312
 313 #endif /* _COMMAND_H_ */