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) 1993-2010 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
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    Bash is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with Bash.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  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   r_append_err_and_out
  36 };
  37
  38 /* Redirection flags; values for rflags */
  39 #define REDIR_VARASSIGN         0x01
  40
  41 /* Redirection errors. */
  42 #define AMBIGUOUS_REDIRECT  -1
  43 #define NOCLOBBER_REDIRECT  -2
  44 #define RESTRICTED_REDIRECT -3  /* can only happen in restricted shells. */
  45 #define HEREDOC_REDIRECT    -4  /* here-doc temp file can't be created */
  46 #define BADVAR_REDIRECT     -5  /* something wrong with {varname}redir */
  47
  48 #define CLOBBERING_REDIRECT(ri) \
  49   (ri == r_output_direction || ri == r_err_and_out)
  50
  51 #define OUTPUT_REDIRECT(ri) \
  52   (ri == r_output_direction || ri == r_input_output || ri == r_err_and_out || ri == r_append_err_and_out)
  53
  54 #define INPUT_REDIRECT(ri) \
  55   (ri == r_input_direction || ri == r_inputa_direction || ri == r_input_output)
  56
  57 #define WRITE_REDIRECT(ri) \
  58   (ri == r_output_direction || \
  59         ri == r_input_output || \
  60         ri == r_err_and_out || \
  61         ri == r_appending_to || \
  62         ri == r_append_err_and_out || \
  63         ri == r_output_force)
  64
  65 /* redirection needs translation */
  66 #define TRANSLATE_REDIRECT(ri) \
  67   (ri == r_duplicating_input_word || ri == r_duplicating_output_word || \
  68    ri == r_move_input_word || ri == r_move_output_word)
  69
  70 /* Command Types: */
  71 enum command_type { cm_for, cm_case, cm_while, cm_if, cm_simple, cm_select,
  72                     cm_connection, cm_function_def, cm_until, cm_group,
  73                     cm_arith, cm_cond, cm_arith_for, cm_subshell, cm_coproc };
  74
  75 /* Possible values for the `flags' field of a WORD_DESC. */
  76 #define W_HASDOLLAR     0x000001        /* Dollar sign present. */
  77 #define W_QUOTED        0x000002        /* Some form of quote character is present. */
  78 #define W_ASSIGNMENT    0x000004        /* This word is a variable assignment. */
  79 #define W_GLOBEXP       0x000008        /* This word is the result of a glob expansion. */
  80 #define W_NOSPLIT       0x000010        /* Do not perform word splitting on this word because ifs is empty string. */
  81 #define W_NOGLOB        0x000020        /* Do not perform globbing on this word. */
  82 #define W_NOSPLIT2      0x000040        /* Don't split word except for $@ expansion (using spaces) because context does not allow it. */
  83 #define W_TILDEEXP      0x000080        /* Tilde expand this assignment word */
  84 #define W_DOLLARAT      0x000100        /* $@ and its special handling */
  85 #define W_DOLLARSTAR    0x000200        /* $* and its special handling */
  86 #define W_NOCOMSUB      0x000400        /* Don't perform command substitution on this word */
  87 #define W_ASSIGNRHS     0x000800        /* Word is rhs of an assignment statement */
  88 #define W_NOTILDE       0x001000        /* Don't perform tilde expansion on this word */
  89 #define W_ITILDE        0x002000        /* Internal flag for word expansion */
  90 #define W_NOEXPAND      0x004000        /* Don't expand at all -- do quote removal */
  91 #define W_COMPASSIGN    0x008000        /* Compound assignment */
  92 #define W_ASSNBLTIN     0x010000        /* word is a builtin command that takes assignments */
  93 #define W_ASSIGNARG     0x020000        /* word is assignment argument to command */
  94 #define W_HASQUOTEDNULL 0x040000        /* word contains a quoted null character */
  95 #define W_DQUOTE        0x080000        /* word should be treated as if double-quoted */
  96 #define W_NOPROCSUB     0x100000        /* don't perform process substitution */
  97 #define W_HASCTLESC     0x200000        /* word contains literal CTLESC characters */
  98 #define W_ASSIGNASSOC   0x400000        /* word looks like associative array assignment */
  99 #define W_ARRAYIND      0x800000        /* word is an array index being expanded */
 100
 101 /* Possible values for subshell_environment */
 102 #define SUBSHELL_ASYNC  0x01    /* subshell caused by `command &' */
 103 #define SUBSHELL_PAREN  0x02    /* subshell caused by ( ... ) */
 104 #define SUBSHELL_COMSUB 0x04    /* subshell caused by `command` or $(command) */
 105 #define SUBSHELL_FORK   0x08    /* subshell caused by executing a disk command */
 106 #define SUBSHELL_PIPE   0x10    /* subshell from a pipeline element */
 107 #define SUBSHELL_PROCSUB 0x20   /* subshell caused by <(command) or >(command) */
 108 #define SUBSHELL_COPROC 0x40    /* subshell from a coproc pipeline */
 109 #define SUBSHELL_RESETTRAP 0x80 /* subshell needs to reset trap strings on first call to trap */
 110
 111 /* A structure which represents a word. */
 112 typedef struct word_desc {
 113   char *word;           /* Zero terminated string. */
 114   int flags;            /* Flags associated with this word. */
 115 } WORD_DESC;
 116
 117 /* A linked list of words. */
 118 typedef struct word_list {
 119   struct word_list *next;
 120   WORD_DESC *word;
 121 } WORD_LIST;
 122
 123
 124 /* **************************************************************** */
 125 /*                                                                  */
 126 /*                      Shell Command Structs                       */
 127 /*                                                                  */
 128 /* **************************************************************** */
 129
 130 /* What a redirection descriptor looks like.  If the redirection instruction
 131    is ri_duplicating_input or ri_duplicating_output, use DEST, otherwise
 132    use the file in FILENAME.  Out-of-range descriptors are identified by a
 133    negative DEST. */
 134
 135 typedef union {
 136   int dest;                     /* Place to redirect REDIRECTOR to, or ... */
 137   WORD_DESC *filename;          /* filename to redirect to. */
 138 } REDIRECTEE;
 139
 140 /* Structure describing a redirection.  If REDIRECTOR is negative, the parser
 141    (or translator in redir.c) encountered an out-of-range file descriptor. */
 142 typedef struct redirect {
 143   struct redirect *next;        /* Next element, or NULL. */
 144   REDIRECTEE redirector;        /* Descriptor or varname to be redirected. */
 145   int rflags;                   /* Private flags for this redirection */
 146   int flags;                    /* Flag value for `open'. */
 147   enum r_instruction  instruction; /* What to do with the information. */
 148   REDIRECTEE redirectee;        /* File descriptor or filename */
 149   char *here_doc_eof;           /* The word that appeared in <<foo. */
 150 } REDIRECT;
 151
 152 /* An element used in parsing.  A single word or a single redirection.
 153    This is an ephemeral construct. */
 154 typedef struct element {
 155   WORD_DESC *word;
 156   REDIRECT *redirect;
 157 } ELEMENT;
 158
 159 /* Possible values for command->flags. */
 160 #define CMD_WANT_SUBSHELL  0x01 /* User wants a subshell: ( command ) */
 161 #define CMD_FORCE_SUBSHELL 0x02 /* Shell needs to force a subshell. */
 162 #define CMD_INVERT_RETURN  0x04 /* Invert the exit value. */
 163 #define CMD_IGNORE_RETURN  0x08 /* Ignore the exit value.  For set -e. */
 164 #define CMD_NO_FUNCTIONS   0x10 /* Ignore functions during command lookup. */
 165 #define CMD_INHIBIT_EXPANSION 0x20 /* Do not expand the command words. */
 166 #define CMD_NO_FORK        0x40 /* Don't fork; just call execve */
 167 #define CMD_TIME_PIPELINE  0x80 /* Time a pipeline */
 168 #define CMD_TIME_POSIX     0x100 /* time -p; use POSIX.2 time output spec. */
 169 #define CMD_AMPERSAND      0x200 /* command & */
 170 #define CMD_STDIN_REDIR    0x400 /* async command needs implicit </dev/null */
 171 #define CMD_COMMAND_BUILTIN 0x0800 /* command executed by `command' builtin */
 172 #define CMD_COPROC_SUBSHELL 0x1000
 173 #define CMD_LASTPIPE        0x2000
 174
 175 /* What a command looks like. */
 176 typedef struct command {
 177   enum command_type type;       /* FOR CASE WHILE IF CONNECTION or SIMPLE. */
 178   int flags;                    /* Flags controlling execution environment. */
 179   int line;                     /* line number the command starts on */
 180   REDIRECT *redirects;          /* Special redirects for FOR CASE, etc. */
 181   union {
 182     struct for_com *For;
 183     struct case_com *Case;
 184     struct while_com *While;
 185     struct if_com *If;
 186     struct connection *Connection;
 187     struct simple_com *Simple;
 188     struct function_def *Function_def;
 189     struct group_com *Group;
 190 #if defined (SELECT_COMMAND)
 191     struct select_com *Select;
 192 #endif
 193 #if defined (DPAREN_ARITHMETIC)
 194     struct arith_com *Arith;
 195 #endif
 196 #if defined (COND_COMMAND)
 197     struct cond_com *Cond;
 198 #endif
 199 #if defined (ARITH_FOR_COMMAND)
 200     struct arith_for_com *ArithFor;
 201 #endif
 202     struct subshell_com *Subshell;
 203     struct coproc_com *Coproc;
 204   } value;
 205 } COMMAND;
 206
 207 /* Structure used to represent the CONNECTION type. */
 208 typedef struct connection {
 209   int ignore;                   /* Unused; simplifies make_command (). */
 210   COMMAND *first;               /* Pointer to the first command. */
 211   COMMAND *second;              /* Pointer to the second command. */
 212   int connector;                /* What separates this command from others. */
 213 } CONNECTION;
 214
 215 /* Structures used to represent the CASE command. */
 216
 217 /* Values for FLAGS word in a PATTERN_LIST */
 218 #define CASEPAT_FALLTHROUGH     0x01
 219 #define CASEPAT_TESTNEXT        0x02
 220
 221 /* Pattern/action structure for CASE_COM. */
 222 typedef struct pattern_list {
 223   struct pattern_list *next;    /* Clause to try in case this one failed. */
 224   WORD_LIST *patterns;          /* Linked list of patterns to test. */
 225   COMMAND *action;              /* Thing to execute if a pattern matches. */
 226   int flags;
 227 } PATTERN_LIST;
 228
 229 /* The CASE command. */
 230 typedef struct case_com {
 231   int flags;                    /* See description of CMD flags. */
 232   int line;                     /* line number the `case' keyword appears on */
 233   WORD_DESC *word;              /* The thing to test. */
 234   PATTERN_LIST *clauses;        /* The clauses to test against, or NULL. */
 235 } CASE_COM;
 236
 237 /* FOR command. */
 238 typedef struct for_com {
 239   int flags;            /* See description of CMD flags. */
 240   int line;             /* line number the `for' keyword appears on */
 241   WORD_DESC *name;      /* The variable name to get mapped over. */
 242   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 243   COMMAND *action;      /* The action to execute.
 244                            During execution, NAME is bound to successive
 245                            members of MAP_LIST. */
 246 } FOR_COM;
 247
 248 #if defined (ARITH_FOR_COMMAND)
 249 typedef struct arith_for_com {
 250   int flags;
 251   int line;     /* generally used for error messages */
 252   WORD_LIST *init;
 253   WORD_LIST *test;
 254   WORD_LIST *step;
 255   COMMAND *action;
 256 } ARITH_FOR_COM;
 257 #endif
 258
 259 #if defined (SELECT_COMMAND)
 260 /* KSH SELECT command. */
 261 typedef struct select_com {
 262   int flags;            /* See description of CMD flags. */
 263   int line;             /* line number the `select' keyword appears on */
 264   WORD_DESC *name;      /* The variable name to get mapped over. */
 265   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 266   COMMAND *action;      /* The action to execute.
 267                            During execution, NAME is bound to the member of
 268                            MAP_LIST chosen by the user. */
 269 } SELECT_COM;
 270 #endif /* SELECT_COMMAND */
 271
 272 /* IF command. */
 273 typedef struct if_com {
 274   int flags;                    /* See description of CMD flags. */
 275   COMMAND *test;                /* Thing to test. */
 276   COMMAND *true_case;           /* What to do if the test returned non-zero. */
 277   COMMAND *false_case;          /* What to do if the test returned zero. */
 278 } IF_COM;
 279
 280 /* WHILE command. */
 281 typedef struct while_com {
 282   int flags;                    /* See description of CMD flags. */
 283   COMMAND *test;                /* Thing to test. */
 284   COMMAND *action;              /* Thing to do while test is non-zero. */
 285 } WHILE_COM;
 286
 287 #if defined (DPAREN_ARITHMETIC)
 288 /* The arithmetic evaluation command, ((...)).  Just a set of flags and
 289    a WORD_LIST, of which the first element is the only one used, for the
 290    time being. */
 291 typedef struct arith_com {
 292   int flags;
 293   int line;
 294   WORD_LIST *exp;
 295 } ARITH_COM;
 296 #endif /* DPAREN_ARITHMETIC */
 297
 298 /* The conditional command, [[...]].  This is a binary tree -- we slippped
 299    a recursive-descent parser into the YACC grammar to parse it. */
 300 #define COND_AND        1
 301 #define COND_OR         2
 302 #define COND_UNARY      3
 303 #define COND_BINARY     4
 304 #define COND_TERM       5
 305 #define COND_EXPR       6
 306
 307 typedef struct cond_com {
 308   int flags;
 309   int line;
 310   int type;
 311   WORD_DESC *op;
 312   struct cond_com *left, *right;
 313 } COND_COM;
 314
 315 /* The "simple" command.  Just a collection of words and redirects. */
 316 typedef struct simple_com {
 317   int flags;                    /* See description of CMD flags. */
 318   int line;                     /* line number the command starts on */
 319   WORD_LIST *words;             /* The program name, the arguments,
 320                                    variable assignments, etc. */
 321   REDIRECT *redirects;          /* Redirections to perform. */
 322 } SIMPLE_COM;
 323
 324 /* The "function definition" command. */
 325 typedef struct function_def {
 326   int flags;                    /* See description of CMD flags. */
 327   int line;                     /* Line number the function def starts on. */
 328   WORD_DESC *name;              /* The name of the function. */
 329   COMMAND *command;             /* The parsed execution tree. */
 330   char *source_file;            /* file in which function was defined, if any */
 331 } FUNCTION_DEF;
 332
 333 /* A command that is `grouped' allows pipes and redirections to affect all
 334    commands in the group. */
 335 typedef struct group_com {
 336   int ignore;                   /* See description of CMD flags. */
 337   COMMAND *command;
 338 } GROUP_COM;
 339
 340 typedef struct subshell_com {
 341   int flags;
 342   COMMAND *command;
 343 } SUBSHELL_COM;
 344
 345 #define COPROC_RUNNING  0x01
 346 #define COPROC_DEAD     0x02
 347
 348 typedef struct coproc {
 349   char *c_name;
 350   pid_t c_pid;
 351   int c_rfd;
 352   int c_wfd;
 353   int c_rsave;
 354   int c_wsave;
 355   int c_flags;
 356   int c_status;
 357 } Coproc;
 358
 359 typedef struct coproc_com {
 360   int flags;
 361   char *name;
 362   COMMAND *command;
 363 } COPROC_COM;
 364
 365 extern COMMAND *global_command;
 366 extern Coproc sh_coproc;
 367
 368 /* Possible command errors */
 369 #define CMDERR_DEFAULT  0
 370 #define CMDERR_BADTYPE  1
 371 #define CMDERR_BADCONN  2
 372 #define CMDERR_BADJUMP  3
 373
 374 #define CMDERR_LAST     3
 375
 376 /* Forward declarations of functions declared in copy_cmd.c. */
 377
 378 extern FUNCTION_DEF *copy_function_def_contents __P((FUNCTION_DEF *, FUNCTION_DEF *));
 379 extern FUNCTION_DEF *copy_function_def __P((FUNCTION_DEF *));
 380
 381 extern WORD_DESC *copy_word __P((WORD_DESC *));
 382 extern WORD_LIST *copy_word_list __P((WORD_LIST *));
 383 extern REDIRECT *copy_redirect __P((REDIRECT *));
 384 extern REDIRECT *copy_redirects __P((REDIRECT *));
 385 extern COMMAND *copy_command __P((COMMAND *));
 386
 387 #endif /* _COMMAND_H_ */