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) 1993-2020 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     (1 << 0)        /* Dollar sign present. */
  77 #define W_QUOTED        (1 << 1)        /* Some form of quote character is present. */
  78 #define W_ASSIGNMENT    (1 << 2)        /* This word is a variable assignment. */
  79 #define W_SPLITSPACE    (1 << 3)        /* Split this word on " " regardless of IFS */
  80 #define W_NOSPLIT       (1 << 4)        /* Do not perform word splitting on this word because ifs is empty string. */
  81 #define W_NOGLOB        (1 << 5)        /* Do not perform globbing on this word. */
  82 #define W_NOSPLIT2      (1 << 6)        /* Don't split word except for $@ expansion (using spaces) because context does not allow it. */
  83 #define W_TILDEEXP      (1 << 7)        /* Tilde expand this assignment word */
  84 #define W_DOLLARAT      (1 << 8)        /* $@ and its special handling -- UNUSED */
  85 #define W_DOLLARSTAR    (1 << 9)        /* $* and its special handling -- UNUSED */
  86 #define W_NOCOMSUB      (1 << 10)       /* Don't perform command substitution on this word */
  87 #define W_ASSIGNRHS     (1 << 11)       /* Word is rhs of an assignment statement */
  88 #define W_NOTILDE       (1 << 12)       /* Don't perform tilde expansion on this word */
  89 #define W_ITILDE        (1 << 13)       /* Internal flag for word expansion */
  90 #define W_EXPANDRHS     (1 << 14)       /* Expanding word in ${paramOPword} */
  91 #define W_COMPASSIGN    (1 << 15)       /* Compound assignment */
  92 #define W_ASSNBLTIN     (1 << 16)       /* word is a builtin command that takes assignments */
  93 #define W_ASSIGNARG     (1 << 17)       /* word is assignment argument to command */
  94 #define W_HASQUOTEDNULL (1 << 18)       /* word contains a quoted null character */
  95 #define W_DQUOTE        (1 << 19)       /* word should be treated as if double-quoted */
  96 #define W_NOPROCSUB     (1 << 20)       /* don't perform process substitution */
  97 #define W_SAWQUOTEDNULL (1 << 21)       /* word contained a quoted null that was removed */
  98 #define W_ASSIGNASSOC   (1 << 22)       /* word looks like associative array assignment */
  99 #define W_ASSIGNARRAY   (1 << 23)       /* word looks like a compound indexed array assignment */
 100 #define W_ARRAYIND      (1 << 24)       /* word is an array index being expanded */
 101 #define W_ASSNGLOBAL    (1 << 25)       /* word is a global assignment to declare (declare/typeset -g) */
 102 #define W_NOBRACE       (1 << 26)       /* Don't perform brace expansion */
 103 #define W_COMPLETE      (1 << 27)       /* word is being expanded for completion */
 104 #define W_CHKLOCAL      (1 << 28)       /* check for local vars on assignment */
 105 #define W_NOASSNTILDE   (1 << 29)       /* don't do tilde expansion like an assignment statement */
 106 #define W_FORCELOCAL    (1 << 30)       /* force assignments to be to local variables, non-fatal on assignment errors */
 107
 108 /* Flags for the `pflags' argument to param_expand() and various
 109    parameter_brace_expand_xxx functions; also used for string_list_dollar_at */
 110 #define PF_NOCOMSUB     0x01    /* Do not perform command substitution */
 111 #define PF_IGNUNBOUND   0x02    /* ignore unbound vars even if -u set */
 112 #define PF_NOSPLIT2     0x04    /* same as W_NOSPLIT2 */
 113 #define PF_ASSIGNRHS    0x08    /* same as W_ASSIGNRHS */
 114 #define PF_COMPLETE     0x10    /* same as W_COMPLETE, sets SX_COMPLETE */
 115 #define PF_EXPANDRHS    0x20    /* same as W_EXPANDRHS */
 116 #define PF_ALLINDS      0x40    /* array, act as if [@] was supplied */
 117
 118 /* Possible values for subshell_environment */
 119 #define SUBSHELL_ASYNC  0x01    /* subshell caused by `command &' */
 120 #define SUBSHELL_PAREN  0x02    /* subshell caused by ( ... ) */
 121 #define SUBSHELL_COMSUB 0x04    /* subshell caused by `command` or $(command) */
 122 #define SUBSHELL_FORK   0x08    /* subshell caused by executing a disk command */
 123 #define SUBSHELL_PIPE   0x10    /* subshell from a pipeline element */
 124 #define SUBSHELL_PROCSUB 0x20   /* subshell caused by <(command) or >(command) */
 125 #define SUBSHELL_COPROC 0x40    /* subshell from a coproc pipeline */
 126 #define SUBSHELL_RESETTRAP 0x80 /* subshell needs to reset trap strings on first call to trap */
 127
 128 /* A structure which represents a word. */
 129 typedef struct word_desc {
 130   char *word;           /* Zero terminated string. */
 131   int flags;            /* Flags associated with this word. */
 132 } WORD_DESC;
 133
 134 /* A linked list of words. */
 135 typedef struct word_list {
 136   struct word_list *next;
 137   WORD_DESC *word;
 138 } WORD_LIST;
 139
 140
 141 /* **************************************************************** */
 142 /*                                                                  */
 143 /*                      Shell Command Structs                       */
 144 /*                                                                  */
 145 /* **************************************************************** */
 146
 147 /* What a redirection descriptor looks like.  If the redirection instruction
 148    is ri_duplicating_input or ri_duplicating_output, use DEST, otherwise
 149    use the file in FILENAME.  Out-of-range descriptors are identified by a
 150    negative DEST. */
 151
 152 typedef union {
 153   int dest;                     /* Place to redirect REDIRECTOR to, or ... */
 154   WORD_DESC *filename;          /* filename to redirect to. */
 155 } REDIRECTEE;
 156
 157 /* Structure describing a redirection.  If REDIRECTOR is negative, the parser
 158    (or translator in redir.c) encountered an out-of-range file descriptor. */
 159 typedef struct redirect {
 160   struct redirect *next;        /* Next element, or NULL. */
 161   REDIRECTEE redirector;        /* Descriptor or varname to be redirected. */
 162   int rflags;                   /* Private flags for this redirection */
 163   int flags;                    /* Flag value for `open'. */
 164   enum r_instruction  instruction; /* What to do with the information. */
 165   REDIRECTEE redirectee;        /* File descriptor or filename */
 166   char *here_doc_eof;           /* The word that appeared in <<foo. */
 167 } REDIRECT;
 168
 169 /* An element used in parsing.  A single word or a single redirection.
 170    This is an ephemeral construct. */
 171 typedef struct element {
 172   WORD_DESC *word;
 173   REDIRECT *redirect;
 174 } ELEMENT;
 175
 176 /* Possible values for command->flags. */
 177 #define CMD_WANT_SUBSHELL  0x01 /* User wants a subshell: ( command ) */
 178 #define CMD_FORCE_SUBSHELL 0x02 /* Shell needs to force a subshell. */
 179 #define CMD_INVERT_RETURN  0x04 /* Invert the exit value. */
 180 #define CMD_IGNORE_RETURN  0x08 /* Ignore the exit value.  For set -e. */
 181 #define CMD_NO_FUNCTIONS   0x10 /* Ignore functions during command lookup. */
 182 #define CMD_INHIBIT_EXPANSION 0x20 /* Do not expand the command words. */
 183 #define CMD_NO_FORK        0x40 /* Don't fork; just call execve */
 184 #define CMD_TIME_PIPELINE  0x80 /* Time a pipeline */
 185 #define CMD_TIME_POSIX     0x100 /* time -p; use POSIX.2 time output spec. */
 186 #define CMD_AMPERSAND      0x200 /* command & */
 187 #define CMD_STDIN_REDIR    0x400 /* async command needs implicit </dev/null */
 188 #define CMD_COMMAND_BUILTIN 0x0800 /* command executed by `command' builtin */
 189 #define CMD_COPROC_SUBSHELL 0x1000
 190 #define CMD_LASTPIPE        0x2000
 191 #define CMD_STDPATH         0x4000      /* use standard path for command lookup */
 192 #define CMD_TRY_OPTIMIZING  0x8000      /* try to optimize this simple command */
 193
 194 /* What a command looks like. */
 195 typedef struct command {
 196   enum command_type type;       /* FOR CASE WHILE IF CONNECTION or SIMPLE. */
 197   int flags;                    /* Flags controlling execution environment. */
 198   int line;                     /* line number the command starts on */
 199   REDIRECT *redirects;          /* Special redirects for FOR CASE, etc. */
 200   union {
 201     struct for_com *For;
 202     struct case_com *Case;
 203     struct while_com *While;
 204     struct if_com *If;
 205     struct connection *Connection;
 206     struct simple_com *Simple;
 207     struct function_def *Function_def;
 208     struct group_com *Group;
 209 #if defined (SELECT_COMMAND)
 210     struct select_com *Select;
 211 #endif
 212 #if defined (DPAREN_ARITHMETIC)
 213     struct arith_com *Arith;
 214 #endif
 215 #if defined (COND_COMMAND)
 216     struct cond_com *Cond;
 217 #endif
 218 #if defined (ARITH_FOR_COMMAND)
 219     struct arith_for_com *ArithFor;
 220 #endif
 221     struct subshell_com *Subshell;
 222     struct coproc_com *Coproc;
 223   } value;
 224 } COMMAND;
 225
 226 /* Structure used to represent the CONNECTION type. */
 227 typedef struct connection {
 228   int ignore;                   /* Unused; simplifies make_command (). */
 229   COMMAND *first;               /* Pointer to the first command. */
 230   COMMAND *second;              /* Pointer to the second command. */
 231   int connector;                /* What separates this command from others. */
 232 } CONNECTION;
 233
 234 /* Structures used to represent the CASE command. */
 235
 236 /* Values for FLAGS word in a PATTERN_LIST */
 237 #define CASEPAT_FALLTHROUGH     0x01
 238 #define CASEPAT_TESTNEXT        0x02
 239
 240 /* Pattern/action structure for CASE_COM. */
 241 typedef struct pattern_list {
 242   struct pattern_list *next;    /* Clause to try in case this one failed. */
 243   WORD_LIST *patterns;          /* Linked list of patterns to test. */
 244   COMMAND *action;              /* Thing to execute if a pattern matches. */
 245   int flags;
 246 } PATTERN_LIST;
 247
 248 /* The CASE command. */
 249 typedef struct case_com {
 250   int flags;                    /* See description of CMD flags. */
 251   int line;                     /* line number the `case' keyword appears on */
 252   WORD_DESC *word;              /* The thing to test. */
 253   PATTERN_LIST *clauses;        /* The clauses to test against, or NULL. */
 254 } CASE_COM;
 255
 256 /* FOR command. */
 257 typedef struct for_com {
 258   int flags;            /* See description of CMD flags. */
 259   int line;             /* line number the `for' keyword appears on */
 260   WORD_DESC *name;      /* The variable name to get mapped over. */
 261   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 262   COMMAND *action;      /* The action to execute.
 263                            During execution, NAME is bound to successive
 264                            members of MAP_LIST. */
 265 } FOR_COM;
 266
 267 #if defined (ARITH_FOR_COMMAND)
 268 typedef struct arith_for_com {
 269   int flags;
 270   int line;     /* generally used for error messages */
 271   WORD_LIST *init;
 272   WORD_LIST *test;
 273   WORD_LIST *step;
 274   COMMAND *action;
 275 } ARITH_FOR_COM;
 276 #endif
 277
 278 #if defined (SELECT_COMMAND)
 279 /* KSH SELECT command. */
 280 typedef struct select_com {
 281   int flags;            /* See description of CMD flags. */
 282   int line;             /* line number the `select' keyword appears on */
 283   WORD_DESC *name;      /* The variable name to get mapped over. */
 284   WORD_LIST *map_list;  /* The things to map over.  This is never NULL. */
 285   COMMAND *action;      /* The action to execute.
 286                            During execution, NAME is bound to the member of
 287                            MAP_LIST chosen by the user. */
 288 } SELECT_COM;
 289 #endif /* SELECT_COMMAND */
 290
 291 /* IF command. */
 292 typedef struct if_com {
 293   int flags;                    /* See description of CMD flags. */
 294   COMMAND *test;                /* Thing to test. */
 295   COMMAND *true_case;           /* What to do if the test returned non-zero. */
 296   COMMAND *false_case;          /* What to do if the test returned zero. */
 297 } IF_COM;
 298
 299 /* WHILE command. */
 300 typedef struct while_com {
 301   int flags;                    /* See description of CMD flags. */
 302   COMMAND *test;                /* Thing to test. */
 303   COMMAND *action;              /* Thing to do while test is non-zero. */
 304 } WHILE_COM;
 305
 306 #if defined (DPAREN_ARITHMETIC)
 307 /* The arithmetic evaluation command, ((...)).  Just a set of flags and
 308    a WORD_LIST, of which the first element is the only one used, for the
 309    time being. */
 310 typedef struct arith_com {
 311   int flags;
 312   int line;
 313   WORD_LIST *exp;
 314 } ARITH_COM;
 315 #endif /* DPAREN_ARITHMETIC */
 316
 317 /* The conditional command, [[...]].  This is a binary tree -- we slipped
 318    a recursive-descent parser into the YACC grammar to parse it. */
 319 #define COND_AND        1
 320 #define COND_OR         2
 321 #define COND_UNARY      3
 322 #define COND_BINARY     4
 323 #define COND_TERM       5
 324 #define COND_EXPR       6
 325
 326 typedef struct cond_com {
 327   int flags;
 328   int line;
 329   int type;
 330   WORD_DESC *op;
 331   struct cond_com *left, *right;
 332 } COND_COM;
 333
 334 /* The "simple" command.  Just a collection of words and redirects. */
 335 typedef struct simple_com {
 336   int flags;                    /* See description of CMD flags. */
 337   int line;                     /* line number the command starts on */
 338   WORD_LIST *words;             /* The program name, the arguments,
 339                                    variable assignments, etc. */
 340   REDIRECT *redirects;          /* Redirections to perform. */
 341 } SIMPLE_COM;
 342
 343 /* The "function definition" command. */
 344 typedef struct function_def {
 345   int flags;                    /* See description of CMD flags. */
 346   int line;                     /* Line number the function def starts on. */
 347   WORD_DESC *name;              /* The name of the function. */
 348   COMMAND *command;             /* The parsed execution tree. */
 349   char *source_file;            /* file in which function was defined, if any */
 350 } FUNCTION_DEF;
 351
 352 /* A command that is `grouped' allows pipes and redirections to affect all
 353    commands in the group. */
 354 typedef struct group_com {
 355   int ignore;                   /* See description of CMD flags. */
 356   COMMAND *command;
 357 } GROUP_COM;
 358
 359 typedef struct subshell_com {
 360   int flags;
 361   int line;
 362   COMMAND *command;
 363 } SUBSHELL_COM;
 364
 365 #define COPROC_RUNNING  0x01
 366 #define COPROC_DEAD     0x02
 367
 368 typedef struct coproc {
 369   char *c_name;
 370   pid_t c_pid;
 371   int c_rfd;
 372   int c_wfd;
 373   int c_rsave;
 374   int c_wsave;
 375   int c_flags;
 376   int c_status;
 377   int c_lock;
 378 } Coproc;
 379
 380 typedef struct coproc_com {
 381   int flags;
 382   char *name;
 383   COMMAND *command;
 384 } COPROC_COM;
 385
 386 extern COMMAND *global_command;
 387 extern Coproc sh_coproc;
 388
 389 /* Possible command errors */
 390 #define CMDERR_DEFAULT  0
 391 #define CMDERR_BADTYPE  1
 392 #define CMDERR_BADCONN  2
 393 #define CMDERR_BADJUMP  3
 394
 395 #define CMDERR_LAST     3
 396
 397 /* Forward declarations of functions declared in copy_cmd.c. */
 398
 399 extern FUNCTION_DEF *copy_function_def_contents PARAMS((FUNCTION_DEF *, FUNCTION_DEF *));
 400 extern FUNCTION_DEF *copy_function_def PARAMS((FUNCTION_DEF *));
 401
 402 extern WORD_DESC *copy_word PARAMS((WORD_DESC *));
 403 extern WORD_LIST *copy_word_list PARAMS((WORD_LIST *));
 404 extern REDIRECT *copy_redirect PARAMS((REDIRECT *));
 405 extern REDIRECT *copy_redirects PARAMS((REDIRECT *));
 406 extern COMMAND *copy_command PARAMS((COMMAND *));
 407
 408 #endif /* _COMMAND_H_ */