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-rw-r--r--eval.c356
1 files changed, 356 insertions, 0 deletions
diff --git a/eval.c b/eval.c
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+/* eval.c -- reading and evaluating commands. */
+
+/* Copyright (C) 1996-2011 Free Software Foundation, Inc.
+
+ This file is part of GNU Bash, the Bourne Again SHell.
+
+ Bash is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ Bash is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Bash. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config.h"
+
+#if defined (HAVE_UNISTD_H)
+# ifdef _MINIX
+# include <sys/types.h>
+# endif
+# include <unistd.h>
+#endif
+
+#include "bashansi.h"
+#include <stdio.h>
+
+#include <signal.h>
+
+#include "bashintl.h"
+
+#include "shell.h"
+#include "parser.h"
+#include "flags.h"
+#include "trap.h"
+
+#include "builtins/common.h"
+
+#include "input.h"
+#include "execute_cmd.h"
+
+#if defined (HISTORY)
+# include "bashhist.h"
+#endif
+
+#if defined (HAVE_POSIX_SIGNALS)
+extern sigset_t top_level_mask;
+#endif
+
+static void send_pwd_to_eterm __P((void));
+static sighandler alrm_catcher __P((int));
+
+/* Read and execute commands until EOF is reached. This assumes that
+ the input source has already been initialized. */
+int
+reader_loop ()
+{
+ int our_indirection_level;
+ COMMAND * volatile current_command;
+
+ USE_VAR(current_command);
+
+ current_command = (COMMAND *)NULL;
+
+ our_indirection_level = ++indirection_level;
+
+ if (just_one_command)
+ reset_readahead_token ();
+
+ while (EOF_Reached == 0)
+ {
+ int code;
+
+ code = setjmp_nosigs (top_level);
+
+#if defined (PROCESS_SUBSTITUTION)
+ unlink_fifo_list ();
+#endif /* PROCESS_SUBSTITUTION */
+
+ /* XXX - why do we set this every time through the loop? And why do
+ it if SIGINT is trapped in an interactive shell? */
+ if (interactive_shell && signal_is_ignored (SIGINT) == 0 && signal_is_trapped (SIGINT) == 0)
+ set_signal_handler (SIGINT, sigint_sighandler);
+
+ if (code != NOT_JUMPED)
+ {
+ indirection_level = our_indirection_level;
+
+ switch (code)
+ {
+ /* Some kind of throw to top_level has occurred. */
+ case FORCE_EOF:
+ case ERREXIT:
+ case EXITPROG:
+ current_command = (COMMAND *)NULL;
+ if (exit_immediately_on_error)
+ variable_context = 0; /* not in a function */
+ EOF_Reached = EOF;
+ goto exec_done;
+
+ case DISCARD:
+ /* Make sure the exit status is reset to a non-zero value, but
+ leave existing non-zero values (e.g., > 128 on signal)
+ alone. */
+ if (last_command_exit_value == 0)
+ last_command_exit_value = EXECUTION_FAILURE;
+ if (subshell_environment)
+ {
+ current_command = (COMMAND *)NULL;
+ EOF_Reached = EOF;
+ goto exec_done;
+ }
+ /* Obstack free command elements, etc. */
+ if (current_command)
+ {
+ dispose_command (current_command);
+ current_command = (COMMAND *)NULL;
+ }
+#if defined (HAVE_POSIX_SIGNALS)
+ sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
+#endif
+ break;
+
+ default:
+ command_error ("reader_loop", CMDERR_BADJUMP, code, 0);
+ }
+ }
+
+ executing = 0;
+ if (temporary_env)
+ dispose_used_env_vars ();
+
+#if (defined (ultrix) && defined (mips)) || defined (C_ALLOCA)
+ /* Attempt to reclaim memory allocated with alloca (). */
+ (void) alloca (0);
+#endif
+
+ if (read_command () == 0)
+ {
+ if (interactive_shell == 0 && read_but_dont_execute)
+ {
+ last_command_exit_value = EXECUTION_SUCCESS;
+ dispose_command (global_command);
+ global_command = (COMMAND *)NULL;
+ }
+ else if (current_command = global_command)
+ {
+ global_command = (COMMAND *)NULL;
+
+ /* If the shell is interactive, expand and display $PS0 after reading a
+ command (possibly a list or pipeline) and before executing it. */
+ if (interactive && ps0_prompt)
+ {
+ char *ps0_string;
+
+ ps0_string = decode_prompt_string (ps0_prompt);
+ if (ps0_string && *ps0_string)
+ {
+ fprintf (stderr, "%s", ps0_string);
+ fflush (stderr);
+ }
+ free (ps0_string);
+ }
+
+ current_command_number++;
+
+ executing = 1;
+ stdin_redir = 0;
+
+ execute_command (current_command);
+
+ exec_done:
+ QUIT;
+
+ if (current_command)
+ {
+ dispose_command (current_command);
+ current_command = (COMMAND *)NULL;
+ }
+ }
+ }
+ else
+ {
+ /* Parse error, maybe discard rest of stream if not interactive. */
+ if (interactive == 0)
+ EOF_Reached = EOF;
+ }
+ if (just_one_command)
+ EOF_Reached = EOF;
+ }
+ indirection_level--;
+ return (last_command_exit_value);
+}
+
+/* Pretty print shell scripts */
+int
+pretty_print_loop ()
+{
+ COMMAND *current_command;
+ char *command_to_print;
+ int code;
+ int global_posix_mode, last_was_newline;
+
+ global_posix_mode = posixly_correct;
+ last_was_newline = 0;
+ while (EOF_Reached == 0)
+ {
+ code = setjmp_nosigs (top_level);
+ if (code)
+ return (EXECUTION_FAILURE);
+ if (read_command() == 0)
+ {
+ current_command = global_command;
+ global_command = 0;
+ posixly_correct = 1; /* print posix-conformant */
+ if (current_command && (command_to_print = make_command_string (current_command)))
+ {
+ printf ("%s\n", command_to_print); /* for now */
+ last_was_newline = 0;
+ }
+ else if (last_was_newline == 0)
+ {
+ printf ("\n");
+ last_was_newline = 1;
+ }
+ posixly_correct = global_posix_mode;
+ dispose_command (current_command);
+ }
+ else
+ return (EXECUTION_FAILURE);
+ }
+
+ return (EXECUTION_SUCCESS);
+}
+
+static sighandler
+alrm_catcher(i)
+ int i;
+{
+ printf (_("\007timed out waiting for input: auto-logout\n"));
+ fflush (stdout);
+ bash_logout (); /* run ~/.bash_logout if this is a login shell */
+ jump_to_top_level (EXITPROG);
+ SIGRETURN (0);
+}
+
+/* Send an escape sequence to emacs term mode to tell it the
+ current working directory. */
+static void
+send_pwd_to_eterm ()
+{
+ char *pwd, *f;
+
+ f = 0;
+ pwd = get_string_value ("PWD");
+ if (pwd == 0)
+ f = pwd = get_working_directory ("eterm");
+ fprintf (stderr, "\032/%s\n", pwd);
+ free (f);
+}
+
+static void
+execute_prompt_command ()
+{
+ char *command_to_execute;
+
+ command_to_execute = get_string_value ("PROMPT_COMMAND");
+ if (command_to_execute)
+ execute_variable_command (command_to_execute, "PROMPT_COMMAND");
+}
+/* Call the YACC-generated parser and return the status of the parse.
+ Input is read from the current input stream (bash_input). yyparse
+ leaves the parsed command in the global variable GLOBAL_COMMAND.
+ This is where PROMPT_COMMAND is executed. */
+int
+parse_command ()
+{
+ int r;
+
+ need_here_doc = 0;
+ run_pending_traps ();
+
+ /* Allow the execution of a random command just before the printing
+ of each primary prompt. If the shell variable PROMPT_COMMAND
+ is set then the value of it is the command to execute. */
+ /* The tests are a combination of SHOULD_PROMPT() and prompt_again()
+ from parse.y, which are the conditions under which the prompt is
+ actually printed. */
+ if (interactive && bash_input.type != st_string && parser_expanding_alias() == 0)
+ {
+ execute_prompt_command ();
+
+ if (running_under_emacs == 2)
+ send_pwd_to_eterm (); /* Yuck */
+ }
+
+ current_command_line_count = 0;
+ r = yyparse ();
+
+ if (need_here_doc)
+ gather_here_documents ();
+
+ return (r);
+}
+
+/* Read and parse a command, returning the status of the parse. The command
+ is left in the globval variable GLOBAL_COMMAND for use by reader_loop.
+ This is where the shell timeout code is executed. */
+int
+read_command ()
+{
+ SHELL_VAR *tmout_var;
+ int tmout_len, result;
+ SigHandler *old_alrm;
+
+ set_current_prompt_level (1);
+ global_command = (COMMAND *)NULL;
+
+ /* Only do timeouts if interactive. */
+ tmout_var = (SHELL_VAR *)NULL;
+ tmout_len = 0;
+ old_alrm = (SigHandler *)NULL;
+
+ if (interactive)
+ {
+ tmout_var = find_variable ("TMOUT");
+
+ if (tmout_var && var_isset (tmout_var))
+ {
+ tmout_len = atoi (value_cell (tmout_var));
+ if (tmout_len > 0)
+ {
+ old_alrm = set_signal_handler (SIGALRM, alrm_catcher);
+ alarm (tmout_len);
+ }
+ }
+ }
+
+ QUIT;
+
+ current_command_line_count = 0;
+ result = parse_command ();
+
+ if (interactive && tmout_var && (tmout_len > 0))
+ {
+ alarm(0);
+ set_signal_handler (SIGALRM, old_alrm);
+ }
+
+ return (result);
+}