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-rw-r--r--builtins/evalstring.c705
1 files changed, 705 insertions, 0 deletions
diff --git a/builtins/evalstring.c b/builtins/evalstring.c
new file mode 100644
index 0000000..1496eee
--- /dev/null
+++ b/builtins/evalstring.c
@@ -0,0 +1,705 @@
+/* evalstring.c - evaluate a string as one or more shell commands. */
+
+/* Copyright (C) 1996-2017 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 __P((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_suppress_fork (command)
+ COMMAND *command;
+{
+ return (startup_state == 2 && parse_and_execute_level == 1 &&
+ running_trap == 0 &&
+ *bash_input.location.string == '\0' &&
+ command->type == cm_simple &&
+ signal_is_trapped (EXIT_TRAP) == 0 &&
+ signal_is_trapped (ERROR_TRAP) == 0 &&
+ any_signals_trapped () < 0 &&
+ command->redirects == 0 && command->value.Simple->redirects == 0 &&
+ ((command->flags & CMD_TIME_PIPELINE) == 0) &&
+ ((command->flags & CMD_INVERT_RETURN) == 0));
+}
+
+void
+optimize_fork (command)
+ COMMAND *command;
+{
+ if (command->type == cm_connection &&
+ (command->value.Connection->connector == AND_AND || command->value.Connection->connector == OR_OR) &&
+ should_suppress_fork (command->value.Connection->second))
+ {
+ 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 (running_trap == 0 &&
+ command->type == cm_simple &&
+ signal_is_trapped (EXIT_TRAP) == 0 &&
+ signal_is_trapped (ERROR_TRAP) == 0 &&
+ any_signals_trapped () < 0 &&
+ command->redirects == 0 && command->value.Simple->redirects == 0 &&
+ ((command->flags & CMD_TIME_PIPELINE) == 0) &&
+ ((command->flags & CMD_INVERT_RETURN) == 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))
+ optimize_subshell_command (command->value.Connection->second);
+}
+
+/* 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
+*/
+
+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))
+ {
+ 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.
+ XXX - change that if we want the function context to be
+ unwound. */
+ if (exit_immediately_on_error && variable_context)
+ {
+ discard_unwind_frame ("pe_dispose");
+ variable_context = 0; /* 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 DISCARD:
+ if (command)
+ run_unwind_frame ("pe_dispose");
+ last_result = last_command_exit_value = EXECUTION_FAILURE; /* XXX */
+ 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)
+ {
+ 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;
+ 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;
+ }
+ else if (command->type == cm_connection)
+ optimize_fork (command);
+#endif /* ONESHOT */
+
+ /* See if this is a candidate for $( <file ). */
+ if (startup_state == 2 &&
+ (subshell_environment & SUBSHELL_COMSUB) &&
+ *bash_input.location.string == '\0' &&
+ 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)
+ {
+ 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 (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 ();
+ }
+
+ 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, endp)
+ char *string;
+ const char *from_file;
+ int flags;
+ 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
+
+/*itrace("parse_string: `%s'", string);*/
+ /* 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;
+ ostring = string;
+
+ with_input_from_string (string, from_file);
+ while (*(bash_input.location.string))
+ {
+ 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)
+ {
+#if defined (DEBUG)
+itrace("parse_string: longjmp executed: code = %d", code);
+#endif
+ should_jump_to_top_level = 0;
+ switch (code)
+ {
+ case FORCE_EOF:
+ case ERREXIT:
+ case EXITPROG:
+ 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)
+ {
+ 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)
+ 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);
+}
+
+/* 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;
+
+ 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);
+ return -1;
+ }
+
+ fd = open(fn, O_RDONLY);
+ if (fd < 0)
+ {
+ file_error (fn);
+ free (fn);
+ 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);
+}