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Diffstat (limited to 'eval.c')
| -rw-r--r-- | eval.c | 356 |
1 files changed, 356 insertions, 0 deletions
@@ -0,0 +1,356 @@ +/* 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); +} |