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ccc6cda3 JA |
1 | /* eval.c -- reading and evaluating commands. |
2 | ||
3 | Copyright (C) 1996 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GNU Bash. | |
6 | ||
7 | Bash is distributed in the hope that it will be useful, but WITHOUT | |
8 | ANY WARRANTY. No author or distributor accepts responsibility to | |
9 | anyone for the consequences of using it or for whether it serves | |
10 | any particular purpose or works at all, unless he says so in | |
11 | writing. Refer to the GNU Emacs General Public License for full | |
12 | details. | |
13 | ||
14 | Everyone is granted permission to copy, modify and redistribute | |
15 | Bash, but only under the conditions described in the GNU General | |
16 | Public License. A copy of this license is supposed to have been | |
17 | given to you along with GNU Emacs so you can know your rights and | |
18 | responsibilities. It should be in a file named COPYING. | |
19 | ||
20 | Among other things, the copyright notice and this notice must be | |
21 | preserved on all copies. */ | |
22 | ||
23 | #include "config.h" | |
24 | ||
25 | #if defined (HAVE_UNISTD_H) | |
cce855bc JA |
26 | # ifdef _MINIX |
27 | # include <sys/types.h> | |
28 | # endif | |
ccc6cda3 JA |
29 | # include <unistd.h> |
30 | #endif | |
31 | ||
32 | #include "bashansi.h" | |
33 | #include <stdio.h> | |
34 | ||
35 | #include "shell.h" | |
36 | #include "flags.h" | |
37 | #include "trap.h" | |
38 | ||
39 | #include "builtins/common.h" | |
40 | ||
41 | #include "input.h" | |
42 | #include "execute_cmd.h" | |
43 | ||
44 | extern int yyparse (); | |
45 | ||
46 | extern int EOF_reached; | |
47 | extern int indirection_level, interactive, interactive_shell; | |
48 | extern int subshell_environment, running_under_emacs; | |
d166f048 | 49 | extern int last_command_exit_value, stdin_redir; |
ccc6cda3 JA |
50 | extern int need_here_doc; |
51 | extern int current_command_number, current_command_line_count, line_number; | |
52 | extern char *ps1_prompt, **prompt_string_pointer; | |
53 | extern int expand_aliases; | |
54 | ||
55 | /* Read and execute commands until EOF is reached. This assumes that | |
56 | the input source has already been initialized. */ | |
57 | int | |
58 | reader_loop () | |
59 | { | |
60 | int our_indirection_level; | |
61 | COMMAND *current_command = (COMMAND *)NULL; | |
62 | ||
63 | our_indirection_level = ++indirection_level; | |
64 | ||
65 | while (EOF_Reached == 0) | |
66 | { | |
67 | int code; | |
68 | ||
69 | code = setjmp (top_level); | |
70 | ||
71 | #if defined (PROCESS_SUBSTITUTION) | |
72 | unlink_fifo_list (); | |
73 | #endif /* PROCESS_SUBSTITUTION */ | |
74 | ||
75 | if (interactive_shell && signal_is_ignored (SIGINT) == 0) | |
76 | set_signal_handler (SIGINT, sigint_sighandler); | |
77 | ||
78 | if (code != NOT_JUMPED) | |
79 | { | |
80 | indirection_level = our_indirection_level; | |
81 | ||
82 | switch (code) | |
83 | { | |
84 | /* Some kind of throw to top_level has occured. */ | |
85 | case FORCE_EOF: | |
86 | case EXITPROG: | |
87 | current_command = (COMMAND *)NULL; | |
88 | EOF_Reached = EOF; | |
89 | goto exec_done; | |
90 | ||
91 | case DISCARD: | |
92 | last_command_exit_value = 1; | |
93 | if (subshell_environment) | |
94 | { | |
95 | current_command = (COMMAND *)NULL; | |
96 | EOF_Reached = EOF; | |
97 | goto exec_done; | |
98 | } | |
99 | /* Obstack free command elements, etc. */ | |
100 | if (current_command) | |
101 | { | |
102 | dispose_command (current_command); | |
103 | current_command = (COMMAND *)NULL; | |
104 | } | |
105 | break; | |
106 | ||
107 | default: | |
108 | programming_error ("reader_loop: bad jump: code %d", code); | |
109 | } | |
110 | } | |
111 | ||
112 | executing = 0; | |
113 | dispose_used_env_vars (); | |
114 | ||
115 | #if (defined (ultrix) && defined (mips)) || defined (C_ALLOCA) | |
116 | /* Attempt to reclaim memory allocated with alloca (). */ | |
117 | (void) alloca (0); | |
118 | #endif | |
119 | ||
120 | if (read_command () == 0) | |
121 | { | |
122 | if (interactive_shell == 0 && read_but_dont_execute) | |
123 | { | |
124 | last_command_exit_value = EXECUTION_SUCCESS; | |
125 | dispose_command (global_command); | |
126 | global_command = (COMMAND *)NULL; | |
127 | } | |
128 | else if (current_command = global_command) | |
129 | { | |
130 | global_command = (COMMAND *)NULL; | |
131 | current_command_number++; | |
132 | ||
133 | executing = 1; | |
d166f048 | 134 | stdin_redir = 0; |
ccc6cda3 JA |
135 | execute_command (current_command); |
136 | ||
137 | exec_done: | |
138 | if (current_command) | |
139 | { | |
140 | dispose_command (current_command); | |
141 | current_command = (COMMAND *)NULL; | |
142 | } | |
143 | ||
144 | QUIT; | |
145 | } | |
146 | } | |
147 | else | |
148 | { | |
149 | /* Parse error, maybe discard rest of stream if not interactive. */ | |
150 | if (interactive == 0) | |
151 | EOF_Reached = EOF; | |
152 | } | |
153 | if (just_one_command) | |
154 | EOF_Reached = EOF; | |
155 | } | |
156 | indirection_level--; | |
157 | return (last_command_exit_value); | |
158 | } | |
159 | ||
160 | static sighandler | |
161 | alrm_catcher(i) | |
162 | int i; | |
163 | { | |
164 | printf ("%ctimed out waiting for input: auto-logout\n", '\07'); | |
165 | jump_to_top_level (EXITPROG); | |
166 | SIGRETURN (0); | |
167 | } | |
168 | ||
169 | /* Send an escape sequence to emacs term mode to tell it the | |
170 | current working directory. */ | |
171 | static void | |
172 | send_pwd_to_eterm () | |
173 | { | |
174 | char *pwd; | |
175 | ||
176 | pwd = get_string_value ("PWD"); | |
177 | if (pwd == 0) | |
178 | pwd = get_working_directory ("eterm"); | |
179 | fprintf (stderr, "\032/%s\n", pwd); | |
180 | } | |
181 | ||
182 | /* Call the YACC-generated parser and return the status of the parse. | |
183 | Input is read from the current input stream (bash_input). yyparse | |
184 | leaves the parsed command in the global variable GLOBAL_COMMAND. | |
185 | This is where PROMPT_COMMAND is executed. */ | |
186 | int | |
187 | parse_command () | |
188 | { | |
189 | int r; | |
190 | char *command_to_execute; | |
191 | ||
192 | need_here_doc = 0; | |
193 | run_pending_traps (); | |
194 | ||
195 | /* Allow the execution of a random command just before the printing | |
196 | of each primary prompt. If the shell variable PROMPT_COMMAND | |
197 | is set then the value of it is the command to execute. */ | |
198 | if (interactive && bash_input.type != st_string) | |
199 | { | |
200 | command_to_execute = get_string_value ("PROMPT_COMMAND"); | |
201 | if (command_to_execute) | |
202 | execute_prompt_command (command_to_execute); | |
203 | ||
204 | if (running_under_emacs == 2) | |
205 | send_pwd_to_eterm (); /* Yuck */ | |
206 | } | |
207 | ||
208 | current_command_line_count = 0; | |
209 | r = yyparse (); | |
210 | ||
211 | if (need_here_doc) | |
212 | gather_here_documents (); | |
213 | ||
214 | return (r); | |
215 | } | |
216 | ||
217 | /* Read and parse a command, returning the status of the parse. The command | |
218 | is left in the globval variable GLOBAL_COMMAND for use by reader_loop. | |
219 | This is where the shell timeout code is executed. */ | |
220 | int | |
221 | read_command () | |
222 | { | |
223 | SHELL_VAR *tmout_var; | |
224 | int tmout_len, result; | |
225 | SigHandler *old_alrm; | |
226 | ||
227 | prompt_string_pointer = &ps1_prompt; | |
228 | global_command = (COMMAND *)NULL; | |
229 | ||
230 | /* Only do timeouts if interactive. */ | |
231 | tmout_var = (SHELL_VAR *)NULL; | |
232 | tmout_len = 0; | |
233 | ||
234 | if (interactive) | |
235 | { | |
236 | tmout_var = find_variable ("TMOUT"); | |
237 | old_alrm = (SigHandler *)NULL; | |
238 | ||
239 | if (tmout_var && tmout_var->value) | |
240 | { | |
241 | tmout_len = atoi (tmout_var->value); | |
242 | if (tmout_len > 0) | |
243 | { | |
244 | old_alrm = set_signal_handler (SIGALRM, alrm_catcher); | |
245 | alarm (tmout_len); | |
246 | } | |
247 | } | |
248 | } | |
249 | ||
250 | QUIT; | |
251 | ||
252 | current_command_line_count = 0; | |
253 | result = parse_command (); | |
254 | ||
255 | if (interactive && tmout_var && (tmout_len > 0)) | |
256 | { | |
257 | alarm(0); | |
258 | set_signal_handler (SIGALRM, old_alrm); | |
259 | } | |
260 | ||
261 | return (result); | |
262 | } | |
cce855bc JA |
263 | |
264 | /* Take a string and run it through the shell parser, returning the | |
265 | resultant word list. Used by compound array assignment. */ | |
266 | WORD_LIST * | |
267 | parse_string_to_word_list (s, whom) | |
268 | char *s, *whom; | |
269 | { | |
270 | WORD_LIST *wl; | |
271 | COMMAND *saved_global; | |
272 | ||
273 | push_stream (1); | |
274 | ||
275 | saved_global = global_command; | |
276 | global_command = (COMMAND *)0; | |
277 | ||
278 | with_input_from_string (s, whom); | |
279 | if (parse_command () != 0 || global_command == 0 || global_command->type != cm_simple) | |
280 | { | |
281 | if (global_command) | |
282 | dispose_command (global_command); | |
283 | wl = (WORD_LIST *)NULL; | |
284 | } | |
285 | else | |
286 | { | |
287 | wl = global_command->value.Simple->words; | |
288 | free (global_command->value.Simple); | |
289 | free (global_command); | |
290 | } | |
291 | ||
292 | global_command = saved_global; | |
293 | ||
294 | pop_stream (); | |
295 | ||
296 | return (wl); | |
297 | } |