diff options
Diffstat (limited to 'builtins/evalstring.c')
| -rw-r--r-- | builtins/evalstring.c | 840 |
1 files changed, 840 insertions, 0 deletions
diff --git a/builtins/evalstring.c b/builtins/evalstring.c new file mode 100644 index 0000000..df3dd68 --- /dev/null +++ b/builtins/evalstring.c @@ -0,0 +1,840 @@ +/* evalstring.c - evaluate a string as one or more shell commands. */ + +/* Copyright (C) 1996-2022 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 <stdio.h> +#include <signal.h> + +#include <errno.h> + +#include "filecntl.h" +#include "../bashansi.h" + +#include "../shell.h" +#include "../jobs.h" +#include "../builtins.h" +#include "../flags.h" +#include "../parser.h" +#include "../input.h" +#include "../execute_cmd.h" +#include "../redir.h" +#include "../trap.h" +#include "../bashintl.h" + +#include <y.tab.h> + +#if defined (HISTORY) +# include "../bashhist.h" +#endif + +#include "common.h" +#include "builtext.h" + +#if !defined (errno) +extern int errno; +#endif + +#define IS_BUILTIN(s) (builtin_address_internal(s, 0) != (struct builtin *)NULL) + +int parse_and_execute_level = 0; + +static int cat_file PARAMS((REDIRECT *)); + +#define PE_TAG "parse_and_execute top" +#define PS_TAG "parse_string top" + +#if defined (HISTORY) +static void +set_history_remembering () +{ + remember_on_history = enable_history_list; +} +#endif + +static void +restore_lastcom (x) + char *x; +{ + FREE (the_printed_command_except_trap); + the_printed_command_except_trap = x; +} + +int +should_optimize_fork (command, subshell) + COMMAND *command; + int subshell; +{ + return (running_trap == 0 && + command->type == cm_simple && + signal_is_trapped (EXIT_TRAP) == 0 && + signal_is_trapped (ERROR_TRAP) == 0 && + any_signals_trapped () < 0 && + (subshell || (command->redirects == 0 && command->value.Simple->redirects == 0)) && + ((command->flags & CMD_TIME_PIPELINE) == 0) && + ((command->flags & CMD_INVERT_RETURN) == 0)); +} + +/* This has extra tests to account for STARTUP_STATE == 2, which is for + -c command but has been extended to command and process substitution + (basically any time you call parse_and_execute in a subshell). */ +int +should_suppress_fork (command) + COMMAND *command; +{ + int subshell; + + subshell = subshell_environment & SUBSHELL_PROCSUB; /* salt to taste */ + return (startup_state == 2 && parse_and_execute_level == 1 && + *bash_input.location.string == '\0' && + parser_expanding_alias () == 0 && + should_optimize_fork (command, subshell)); +} + +int +can_optimize_connection (command) + COMMAND *command; +{ + return (*bash_input.location.string == '\0' && + parser_expanding_alias () == 0 && + (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') && + command->value.Connection->second->type == cm_simple); +} + +void +optimize_connection_fork (command) + COMMAND *command; +{ + if (command->type == cm_connection && + (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') && + (command->value.Connection->second->flags & CMD_TRY_OPTIMIZING) && + (should_suppress_fork (command->value.Connection->second) || + ((subshell_environment & SUBSHELL_PAREN) && should_optimize_fork (command->value.Connection->second, 0)))) + { + command->value.Connection->second->flags |= CMD_NO_FORK; + command->value.Connection->second->value.Simple->flags |= CMD_NO_FORK; + } +} + +void +optimize_subshell_command (command) + COMMAND *command; +{ + if (should_optimize_fork (command, 0)) + { + command->flags |= CMD_NO_FORK; + command->value.Simple->flags |= CMD_NO_FORK; + } + else if (command->type == cm_connection && + (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR || command->value.Connection->connector == ';') && + command->value.Connection->second->type == cm_simple && + parser_expanding_alias () == 0) + { + command->value.Connection->second->flags |= CMD_TRY_OPTIMIZING; + command->value.Connection->second->value.Simple->flags |= CMD_TRY_OPTIMIZING; + } +} + +void +optimize_shell_function (command) + COMMAND *command; +{ + COMMAND *fc; + + fc = (command->type == cm_group) ? command->value.Group->command : command; + + if (fc->type == cm_simple && should_suppress_fork (fc)) + { + fc->flags |= CMD_NO_FORK; + fc->value.Simple->flags |= CMD_NO_FORK; + } + else if (fc->type == cm_connection && can_optimize_connection (fc) && should_suppress_fork (fc->value.Connection->second)) + { + fc->value.Connection->second->flags |= CMD_NO_FORK; + fc->value.Connection->second->value.Simple->flags |= CMD_NO_FORK; + } +} + +int +can_optimize_cat_file (command) + COMMAND *command; +{ + return (command->type == cm_simple && !command->redirects && + (command->flags & CMD_TIME_PIPELINE) == 0 && + command->value.Simple->words == 0 && + command->value.Simple->redirects && + command->value.Simple->redirects->next == 0 && + command->value.Simple->redirects->instruction == r_input_direction && + command->value.Simple->redirects->redirector.dest == 0); +} + +/* How to force parse_and_execute () to clean up after itself. */ +void +parse_and_execute_cleanup (old_running_trap) + int old_running_trap; +{ + if (running_trap > 0) + { + /* We assume if we have a different value for running_trap than when + we started (the only caller that cares is evalstring()), the + original caller will perform the cleanup, and we should not step + on them. */ + if (running_trap != old_running_trap) + run_trap_cleanup (running_trap - 1); + unfreeze_jobs_list (); + } + + if (have_unwind_protects ()) + run_unwind_frame (PE_TAG); + else + parse_and_execute_level = 0; /* XXX */ +} + +static void +parse_prologue (string, flags, tag) + char *string; + int flags; + char *tag; +{ + char *orig_string, *lastcom; + int x; + + orig_string = string; + /* Unwind protect this invocation of parse_and_execute (). */ + begin_unwind_frame (tag); + unwind_protect_int (parse_and_execute_level); + unwind_protect_jmp_buf (top_level); + unwind_protect_int (indirection_level); + unwind_protect_int (line_number); + unwind_protect_int (line_number_for_err_trap); + unwind_protect_int (loop_level); + unwind_protect_int (executing_list); + unwind_protect_int (comsub_ignore_return); + if (flags & (SEVAL_NONINT|SEVAL_INTERACT)) + unwind_protect_int (interactive); + +#if defined (HISTORY) + if (parse_and_execute_level == 0) + add_unwind_protect (set_history_remembering, (char *)NULL); + else + unwind_protect_int (remember_on_history); /* can be used in scripts */ +# if defined (BANG_HISTORY) + unwind_protect_int (history_expansion_inhibited); +# endif /* BANG_HISTORY */ +#endif /* HISTORY */ + + if (interactive_shell) + { + x = get_current_prompt_level (); + add_unwind_protect (set_current_prompt_level, x); + } + + if (the_printed_command_except_trap) + { + lastcom = savestring (the_printed_command_except_trap); + add_unwind_protect (restore_lastcom, lastcom); + } + + add_unwind_protect (pop_stream, (char *)NULL); + if (parser_expanding_alias ()) + add_unwind_protect (parser_restore_alias, (char *)NULL); + + if (orig_string && ((flags & SEVAL_NOFREE) == 0)) + add_unwind_protect (xfree, orig_string); + end_unwind_frame (); + + if (flags & (SEVAL_NONINT|SEVAL_INTERACT)) + interactive = (flags & SEVAL_NONINT) ? 0 : 1; + +#if defined (HISTORY) + if (flags & SEVAL_NOHIST) + bash_history_disable (); +# if defined (BANG_HISTORY) + if (flags & SEVAL_NOHISTEXP) + history_expansion_inhibited = 1; +# endif /* BANG_HISTORY */ +#endif /* HISTORY */ +} + +/* Parse and execute the commands in STRING. Returns whatever + execute_command () returns. This frees STRING. FLAGS is a + flags word; look in common.h for the possible values. Actions + are: + (flags & SEVAL_NONINT) -> interactive = 0; + (flags & SEVAL_INTERACT) -> interactive = 1; + (flags & SEVAL_NOHIST) -> call bash_history_disable () + (flags & SEVAL_NOFREE) -> don't free STRING when finished + (flags & SEVAL_RESETLINE) -> reset line_number to 1 + (flags & SEVAL_NOHISTEXP) -> history_expansion_inhibited -> 1 + (flags & SEVAL_NOOPTIMIZE) -> don't try to turn on optimizing flags +*/ + +int +parse_and_execute (string, from_file, flags) + char *string; + const char *from_file; + int flags; +{ + int code, lreset; + volatile int should_jump_to_top_level, last_result; + COMMAND *volatile command; + volatile sigset_t pe_sigmask; + + parse_prologue (string, flags, PE_TAG); + + parse_and_execute_level++; + + lreset = flags & SEVAL_RESETLINE; + +#if defined (HAVE_POSIX_SIGNALS) + /* If we longjmp and are going to go on, use this to restore signal mask */ + sigemptyset ((sigset_t *)&pe_sigmask); + sigprocmask (SIG_BLOCK, (sigset_t *)NULL, (sigset_t *)&pe_sigmask); +#endif + + /* Reset the line number if the caller wants us to. If we don't reset the + line number, we have to subtract one, because we will add one just + before executing the next command (resetting the line number sets it to + 0; the first line number is 1). */ + push_stream (lreset); + if (parser_expanding_alias ()) + /* push current shell_input_line */ + parser_save_alias (); + + if (lreset == 0) + line_number--; + + indirection_level++; + + code = should_jump_to_top_level = 0; + last_result = EXECUTION_SUCCESS; + + /* We need to reset enough of the token state so we can start fresh. */ + if (current_token == yacc_EOF) + current_token = '\n'; /* reset_parser() ? */ + + with_input_from_string (string, from_file); + clear_shell_input_line (); + while (*(bash_input.location.string) || parser_expanding_alias ()) + { + command = (COMMAND *)NULL; + + if (interrupt_state) + { + last_result = EXECUTION_FAILURE; + break; + } + + /* Provide a location for functions which `longjmp (top_level)' to + jump to. This prevents errors in substitution from restarting + the reader loop directly, for example. */ + code = setjmp_nosigs (top_level); + + if (code) + { + should_jump_to_top_level = 0; + switch (code) + { + case ERREXIT: + /* variable_context -> 0 is what eval.c:reader_loop() does in + these circumstances. Don't bother with cleanup here because + we don't want to run the function execution cleanup stuff + that will cause pop_context and other functions to run. + We call reset_local_contexts() instead, which just frees + context memory. + XXX - change that if we want the function context to be + unwound. */ + if (exit_immediately_on_error && variable_context) + { + discard_unwind_frame ("pe_dispose"); + reset_local_contexts (); /* not in a function */ + } + should_jump_to_top_level = 1; + goto out; + case FORCE_EOF: + case EXITPROG: + if (command) + run_unwind_frame ("pe_dispose"); + /* Remember to call longjmp (top_level) after the old + value for it is restored. */ + should_jump_to_top_level = 1; + goto out; + + case EXITBLTIN: + if (command) + { + if (variable_context && signal_is_trapped (0)) + { + /* Let's make sure we run the exit trap in the function + context, as we do when not running parse_and_execute. + The pe_dispose unwind frame comes before any unwind- + protects installed by the string we're evaluating, so + it will undo the current function scope. */ + dispose_command (command); + discard_unwind_frame ("pe_dispose"); + } + else + run_unwind_frame ("pe_dispose"); + } + should_jump_to_top_level = 1; + goto out; + + case DISCARD: + if (command) + run_unwind_frame ("pe_dispose"); + last_result = last_command_exit_value = EXECUTION_FAILURE; /* XXX */ + set_pipestatus_from_exit (last_command_exit_value); + if (subshell_environment) + { + should_jump_to_top_level = 1; + goto out; + } + else + { +#if 0 + dispose_command (command); /* pe_dispose does this */ +#endif +#if defined (HAVE_POSIX_SIGNALS) + sigprocmask (SIG_SETMASK, (sigset_t *)&pe_sigmask, (sigset_t *)NULL); +#endif + continue; + } + + default: + command_error ("parse_and_execute", CMDERR_BADJUMP, code, 0); + break; + } + } + + if (parse_command () == 0) + { + int local_expalias, local_alflag; + + if ((flags & SEVAL_PARSEONLY) || (interactive_shell == 0 && read_but_dont_execute)) + { + last_result = EXECUTION_SUCCESS; + dispose_command (global_command); + global_command = (COMMAND *)NULL; + } + else if (command = global_command) + { + struct fd_bitmap *bitmap; + + if (flags & SEVAL_FUNCDEF) + { + char *x; + + /* If the command parses to something other than a straight + function definition, or if we have not consumed the entire + string, or if the parser has transformed the function + name (as parsing will if it begins or ends with shell + whitespace, for example), reject the attempt */ + if (command->type != cm_function_def || + ((x = parser_remaining_input ()) && *x) || + (STREQ (from_file, command->value.Function_def->name->word) == 0)) + { + internal_warning (_("%s: ignoring function definition attempt"), from_file); + should_jump_to_top_level = 0; + last_result = last_command_exit_value = EX_BADUSAGE; + set_pipestatus_from_exit (last_command_exit_value); + reset_parser (); + break; + } + } + + bitmap = new_fd_bitmap (FD_BITMAP_SIZE); + begin_unwind_frame ("pe_dispose"); + add_unwind_protect (dispose_fd_bitmap, bitmap); + add_unwind_protect (dispose_command, command); /* XXX */ + + global_command = (COMMAND *)NULL; + + if ((subshell_environment & SUBSHELL_COMSUB) && comsub_ignore_return) + command->flags |= CMD_IGNORE_RETURN; + +#if defined (ONESHOT) + /* + * IF + * we were invoked as `bash -c' (startup_state == 2) AND + * parse_and_execute has not been called recursively AND + * we're not running a trap AND + * we have parsed the full command (string == '\0') AND + * we're not going to run the exit trap AND + * we have a simple command without redirections AND + * the command is not being timed AND + * the command's return status is not being inverted AND + * there aren't any traps in effect + * THEN + * tell the execution code that we don't need to fork + */ + if (should_suppress_fork (command)) + { + command->flags |= CMD_NO_FORK; + command->value.Simple->flags |= CMD_NO_FORK; + } + + /* Can't optimize forks out here execept for simple commands. + This knows that the parser sets up commands as left-side heavy + (&& and || are left-associative) and after the single parse, + if we are at the end of the command string, the last in a + series of connection commands is + command->value.Connection->second. */ + else if (command->type == cm_connection && + (flags & SEVAL_NOOPTIMIZE) == 0 && + can_optimize_connection (command)) + { + command->value.Connection->second->flags |= CMD_TRY_OPTIMIZING; + command->value.Connection->second->value.Simple->flags |= CMD_TRY_OPTIMIZING; + } +#endif /* ONESHOT */ + + /* We play tricks in the parser and command_substitute() turning + expand_aliases on and off depending on which parsing pass and + whether or not we're in posix mode. This only matters for + parsing, and we let the higher layers deal with that. We just + want to ensure that expand_aliases is set to the appropriate + global value when we go to execute this command, so we save + and restore it around the execution (we don't restore it if + the global value of the flag (expaliases_flag) changes). */ + local_expalias = expand_aliases; + local_alflag = expaliases_flag; + if (subshell_environment & SUBSHELL_COMSUB) + expand_aliases = expaliases_flag; + + /* See if this is a candidate for $( <file ). */ + if (startup_state == 2 && + (subshell_environment & SUBSHELL_COMSUB) && + *bash_input.location.string == '\0' && + can_optimize_cat_file (command)) + { + int r; + r = cat_file (command->value.Simple->redirects); + last_result = (r < 0) ? EXECUTION_FAILURE : EXECUTION_SUCCESS; + } + else + last_result = execute_command_internal + (command, 0, NO_PIPE, NO_PIPE, bitmap); + dispose_command (command); + dispose_fd_bitmap (bitmap); + discard_unwind_frame ("pe_dispose"); + + /* If the global value didn't change, we restore what we had. */ + if ((subshell_environment & SUBSHELL_COMSUB) && local_alflag == expaliases_flag) + expand_aliases = local_expalias; + + if (flags & SEVAL_ONECMD) + { + reset_parser (); + break; + } + } + } + else + { + last_result = EX_BADUSAGE; /* was EXECUTION_FAILURE */ + + if (interactive_shell == 0 && this_shell_builtin && + (this_shell_builtin == source_builtin || this_shell_builtin == eval_builtin) && + last_command_exit_value == EX_BADSYNTAX && posixly_correct && executing_command_builtin == 0) + { + should_jump_to_top_level = 1; + code = ERREXIT; + last_command_exit_value = EX_BADUSAGE; + } + + /* Since we are shell compatible, syntax errors in a script + abort the execution of the script. Right? */ + break; + } + } + + out: + + run_unwind_frame (PE_TAG); + + if (interrupt_state && parse_and_execute_level == 0) + { + /* An interrupt during non-interactive execution in an + interactive shell (e.g. via $PROMPT_COMMAND) should + not cause the shell to exit. */ + interactive = interactive_shell; + throw_to_top_level (); + } + + CHECK_TERMSIG; + + if (should_jump_to_top_level) + jump_to_top_level (code); + + return (last_result); +} + +/* Parse a command contained in STRING according to FLAGS and return the + number of characters consumed from the string. If non-NULL, set *ENDP + to the position in the string where the parse ended. Used to validate + command substitutions during parsing to obey Posix rules about finding + the end of the command and balancing parens. */ +int +parse_string (string, from_file, flags, cmdp, endp) + char *string; + const char *from_file; + int flags; + COMMAND **cmdp; + char **endp; +{ + int code, nc; + volatile int should_jump_to_top_level; + COMMAND *volatile command, *oglobal; + char *ostring; + volatile sigset_t ps_sigmask; + + parse_prologue (string, flags, PS_TAG); + +#if defined (HAVE_POSIX_SIGNALS) + /* If we longjmp and are going to go on, use this to restore signal mask */ + sigemptyset ((sigset_t *)&ps_sigmask); + sigprocmask (SIG_BLOCK, (sigset_t *)NULL, (sigset_t *)&ps_sigmask); +#endif + + /* Reset the line number if the caller wants us to. If we don't reset the + line number, we have to subtract one, because we will add one just + before executing the next command (resetting the line number sets it to + 0; the first line number is 1). */ + push_stream (0); + if (parser_expanding_alias ()) + /* push current shell_input_line */ + parser_save_alias (); + + code = should_jump_to_top_level = 0; + oglobal = global_command; + + with_input_from_string (string, from_file); + ostring = bash_input.location.string; + while (*(bash_input.location.string)) /* XXX - parser_expanding_alias () ? */ + { + command = (COMMAND *)NULL; + +#if 0 + if (interrupt_state) + break; +#endif + + /* Provide a location for functions which `longjmp (top_level)' to + jump to. */ + code = setjmp_nosigs (top_level); + + if (code) + { + INTERNAL_DEBUG(("parse_string: longjmp executed: code = %d", code)); + + should_jump_to_top_level = 0; + switch (code) + { + case FORCE_EOF: + case ERREXIT: + case EXITPROG: + case EXITBLTIN: + case DISCARD: /* XXX */ + if (command) + dispose_command (command); + /* Remember to call longjmp (top_level) after the old + value for it is restored. */ + should_jump_to_top_level = 1; + goto out; + + default: +#if defined (HAVE_POSIX_SIGNALS) + sigprocmask (SIG_SETMASK, (sigset_t *)&ps_sigmask, (sigset_t *)NULL); +#endif + command_error ("parse_string", CMDERR_BADJUMP, code, 0); + break; + } + } + + if (parse_command () == 0) + { + if (cmdp) + *cmdp = global_command; + else + dispose_command (global_command); + global_command = (COMMAND *)NULL; + } + else + { + if ((flags & SEVAL_NOLONGJMP) == 0) + { + should_jump_to_top_level = 1; + code = DISCARD; + } + else + reset_parser (); /* XXX - sets token_to_read */ + break; + } + + if (current_token == yacc_EOF || current_token == shell_eof_token) + { + if (current_token == shell_eof_token) + rewind_input_string (); + break; + } + } + +out: + + global_command = oglobal; + nc = bash_input.location.string - ostring; + if (endp) + *endp = bash_input.location.string; + + run_unwind_frame (PS_TAG); + + /* If we return < 0, the caller (xparse_dolparen) will jump_to_top_level for + us, after doing cleanup */ + if (should_jump_to_top_level) + { + if (parse_and_execute_level == 0) + top_level_cleanup (); + if (code == DISCARD) + return -DISCARD; + jump_to_top_level (code); + } + + return (nc); +} + +int +open_redir_file (r, fnp) + REDIRECT *r; + char **fnp; +{ + char *fn; + int fd, rval; + + if (r->instruction != r_input_direction) + return -1; + + /* Get the filename. */ + if (posixly_correct && !interactive_shell) + disallow_filename_globbing++; + fn = redirection_expand (r->redirectee.filename); + if (posixly_correct && !interactive_shell) + disallow_filename_globbing--; + + if (fn == 0) + { + redirection_error (r, AMBIGUOUS_REDIRECT, fn); + return -1; + } + + fd = open(fn, O_RDONLY); + if (fd < 0) + { + file_error (fn); + free (fn); + if (fnp) + *fnp = 0; + return -1; + } + + if (fnp) + *fnp = fn; + return fd; +} + +/* Handle a $( < file ) command substitution. This expands the filename, + returning errors as appropriate, then just cats the file to the standard + output. */ +static int +cat_file (r) + REDIRECT *r; +{ + char *fn; + int fd, rval; + + fd = open_redir_file (r, &fn); + if (fd < 0) + return -1; + + rval = zcatfd (fd, 1, fn); + + free (fn); + close (fd); + + return (rval); +} + +int +evalstring (string, from_file, flags) + char *string; + const char *from_file; + int flags; +{ + volatile int r, rflag, rcatch; + volatile int was_trap; + + /* Are we running a trap when we execute this function? */ + was_trap = running_trap; + + rcatch = 0; + rflag = return_catch_flag; + /* If we are in a place where `return' is valid, we have to catch + `eval "... return"' and make sure parse_and_execute cleans up. Then + we can trampoline to the previous saved return_catch location. */ + if (rflag) + { + begin_unwind_frame ("evalstring"); + + unwind_protect_int (return_catch_flag); + unwind_protect_jmp_buf (return_catch); + + return_catch_flag++; /* increment so we have a counter */ + rcatch = setjmp_nosigs (return_catch); + } + + if (rcatch) + { + /* We care about whether or not we are running the same trap we were + when we entered this function. */ + parse_and_execute_cleanup (was_trap); + r = return_catch_value; + } + else + /* Note that parse_and_execute () frees the string it is passed. */ + r = parse_and_execute (string, from_file, flags); + + if (rflag) + { + run_unwind_frame ("evalstring"); + if (rcatch && return_catch_flag) + { + return_catch_value = r; + sh_longjmp (return_catch, 1); + } + } + + return (r); +} |