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i-bash/shell.c

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Imported from ../bash-1.14.7.tar.gz.
1996-08-26 18:22:31 +00:00
/* shell.c -- GNU's idea of the POSIX shell specification.
This file is part of Bash, the Bourne Again SHell. Bash is free
software; no one can prevent you from reading the source code, or
giving it to someone else. This file is copyrighted under the GNU
General Public License, which can be found in the file called
COPYING.
Copyright (C) 1988, 1991 Free Software Foundation, Inc.
This file is part of GNU Bash.
Bash is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY. No author or distributor accepts responsibility to
anyone for the consequences of using it or for whether it serves
any particular purpose or works at all, unless he says so in
writing. Refer to the GNU Emacs General Public License for full
details.
Everyone is granted permission to copy, modify and redistribute
Bash, but only under the conditions described in the GNU General
Public License. A copy of this license is supposed to have been
given to you along with GNU Emacs so you can know your rights and
responsibilities. It should be in a file named COPYING.
Among other things, the copyright notice and this notice must be
preserved on all copies.
Birthdate:
Sunday, January 10th, 1988.
Initial author: Brian Fox
*/
#define INSTALL_DEBUG_MODE
#include "bashtypes.h"
#include <stdio.h>
#include <signal.h>
#include <errno.h>
#include <sys/file.h>
#include "filecntl.h"
#include <pwd.h>
#include "posixstat.h"
#include "bashansi.h"
#if defined (HAVE_VARARGS_H)
#include <varargs.h>
#endif
#include "shell.h"
#include "flags.h"
#if defined (JOB_CONTROL)
#include "jobs.h"
#endif /* JOB_CONTROL */
#include "input.h"
#include "execute_cmd.h"
#if defined (HISTORY)
# include "bashhist.h"
# include <readline/history.h>
#endif
#include <tilde/tilde.h>
#if defined (USG) && !defined (HAVE_GETPW_DECLS)
extern struct passwd *getpwuid ();
#endif /* USG && !HAVE_GETPW_DECLS */
extern int yydebug;
#if !defined (errno)
extern int errno;
#endif
extern char *dist_version;
extern int patch_level, build_version;
extern int subshell_environment; /* Found in execute_cmd.c. */
extern int last_command_exit_value;
extern int return_catch_flag;
extern jmp_buf return_catch;
extern int need_here_doc, current_command_line_count, line_number;
extern char *ps1_prompt, **prompt_string_pointer;
extern int loop_level, continuing, breaking;
extern int parse_and_execute_level;
extern char *this_command_name;
/* Non-zero means that this shell has already been run; i.e. you should
call shell_reinitialize () if you need to start afresh. */
static int shell_initialized = 0;
static int sourced_env = 0;
/* The current maintainer of the shell. You change this in the
Makefile. */
#if !defined (MAINTAINER)
#define MAINTAINER "bash-maintainers@prep.ai.mit.edu"
#endif
char *the_current_maintainer = MAINTAINER;
char *primary_prompt = PPROMPT;
char *secondary_prompt = SPROMPT;
COMMAND *global_command = (COMMAND *)NULL;
/* Non-zero after SIGINT. */
int interrupt_state = 0;
/* Information about the current user. */
struct user_info current_user =
{
-1, -1, -1, -1, (char *)NULL, (char *)NULL, (char *)NULL
};
/* The current host's name. */
char *current_host_name = (char *)NULL;
/* Non-zero means that this shell is a login shell.
Specifically:
0 = not login shell.
1 = login shell from getty (or equivalent fake out)
-1 = login shell from "-login" flag.
-2 = both from getty, and from flag.
*/
int login_shell = 0;
/* Non-zero means that at this moment, the shell is interactive. In
general, this means that the shell is at this moment reading input
from the keyboard. */
int interactive = 0;
/* Non-zero means that the shell was started as an interactive shell. */
int interactive_shell = 0;
/* Tells what state the shell was in when it started:
0 = non-interactive shell script
1 = interactive
2 = -c command
This is a superset of the information provided by interactive_shell.
*/
int startup_state = 0;
/* Special debugging helper. */
int debugging_login_shell = 0;
/* The environment that the shell passes to other commands. */
char **shell_environment;
/* Non-zero when we are executing a top-level command. */
int executing = 0;
/* The number of commands executed so far. */
int current_command_number = 1;
/* The environment at the top-level REP loop. We use this in the case of
error return. */
jmp_buf top_level, catch;
#if defined (JOB_CONTROL) || defined (_POSIX_VERSION)
/* The signal masks that this shell runs with. */
sigset_t top_level_mask;
#endif /* JOB_CONTROL */
/* Non-zero is the recursion depth for commands. */
int indirection_level = 0;
/* The number of times BASH has been executed. This is set
by initialize_variables () in variables.c. */
int shell_level = 0;
/* The name of this shell, as taken from argv[0]. */
char *shell_name = (char *)NULL;
/* time in seconds when the shell was started */
time_t shell_start_time;
/* The name of the .(shell)rc file. */
static char *bashrc_file = "~/.bashrc";
/* Non-zero means to act more like the Bourne shell on startup. */
static int act_like_sh = 0;
/* Values for the long-winded argument names. */
static int debugging = 0; /* Do debugging things. */
static int no_rc = 0; /* Don't execute ~/.bashrc */
static int no_profile = 0; /* Don't execute .profile */
static int do_version = 0; /* Display interesting version info. */
static int quiet = 0; /* Be quiet when starting up. */
static int make_login_shell = 0; /* Make this shell be a `-bash' shell. */
int no_line_editing = 0; /* Don't do fancy line editing. */
int no_brace_expansion = 0; /* Non-zero means no foo{a,b} -> fooa foob. */
int posixly_correct = 0; /* Non-zero means posix.2 superset. */
/* Some long-winded argument names. These are obviously new. */
#define Int 1
#define Charp 2
struct {
char *name;
int type;
int *int_value;
char **char_value;
} long_args[] = {
{ "debug", Int, &debugging, (char **)0x0 },
{ "norc", Int, &no_rc, (char **)0x0 },
{ "noprofile", Int, &no_profile, (char **)0x0 },
{ "rcfile", Charp, (int *)0x0, &bashrc_file },
{ "version", Int, &do_version, (char **)0x0 },
{ "quiet", Int, &quiet, (char **)0x0 },
{ "login", Int, &make_login_shell, (char **)0x0 },
{ "nolineediting", Int, &no_line_editing, (char **)0x0 },
{ "nobraceexpansion", Int, &no_brace_expansion, (char **)0x0 },
{ "posix", Int, &posixly_correct, (char **)0x0 },
{ (char *)0x0, Int, (int *)0x0, (char **)0x0 }
};
/* These are extern so execute_simple_command can set them, and then
longjmp back to main to execute a shell script, instead of calling
main () again and resulting in indefinite, possibly fatal, stack
growth. */
jmp_buf subshell_top_level;
int subshell_argc;
char **subshell_argv;
char **subshell_envp;
#if defined (BUFFERED_INPUT)
/* The file descriptor from which the shell is reading input. */
int default_buffered_input = -1;
#endif
static int want_pending_command;
static char *local_pending_command;
static int isnetconn ();
static void run_startup_files ();
static void shell_initialize ();
static void shell_reinitialize ();
static void initialize_signals ();
static void initialize_terminating_signals ();
main (argc, argv, env)
int argc;
char **argv, **env;
{
register int i;
int arg_index, locally_skip_execution;
int top_level_arg_index, read_from_stdin;
FILE *default_input;
/* There is a bug in the NeXT 2.1 rlogind that causes opens
of /dev/tty to fail. */
#if defined (RLOGIN_PGRP_BUG)
{
int tty_fd;
tty_fd = open ("/dev/tty", O_RDWR);
if (tty_fd < 0)
{
char *tty;
tty = (char *)ttyname (fileno (stdin));
tty_fd = open (tty, O_RDWR);
}
close (tty_fd);
}
#endif /* RLOGIN_PGRP_BUG */
/* Wait forever if we are debugging a login shell. */
while (debugging_login_shell);
current_user.uid = getuid ();
current_user.gid = getgid ();
current_user.euid = geteuid ();
current_user.egid = getegid ();
/* See whether or not we are running setuid or setgid. */
privileged_mode = (current_user.uid != current_user.euid) ||
(current_user.gid != current_user.egid);
posixly_correct = (getenv ("POSIXLY_CORRECT") != (char *)NULL) ||
(getenv ("POSIX_PEDANTIC") != (char *)NULL);
#if defined (USE_GNU_MALLOC_LIBRARY)
mcheck (programming_error, (void (*) ())0);
#endif /* USE_GNU_MALLOC_LIBRARY */
if (setjmp (subshell_top_level))
{
argc = subshell_argc;
argv = subshell_argv;
env = subshell_envp;
sourced_env = 0;
}
/* Initialize local variables for all `invocations' of main (). */
arg_index = 1;
local_pending_command = (char *)NULL;
want_pending_command = 0;
locally_skip_execution = 0;
read_from_stdin = 0;
default_input = stdin;
#if defined (BUFFERED_INPUT)
default_buffered_input = -1;
#endif
/* Fix for the `infinite process creation' bug when running shell scripts
from startup files on System V. */
login_shell = make_login_shell = 0;
/* If this shell has already been run, then reinitialize it to a
vanilla state. */
if (shell_initialized || shell_name)
{
/* Make sure that we do not infinitely recurse as a login shell. */
if (*shell_name == '-')
shell_name++;
shell_reinitialize ();
if (setjmp (top_level))
exit (2);
}
/* Here's a hack. If the name of this shell is "sh", then don't do
any startup files; just try to be more like /bin/sh. */
/* XXX - next version - make this be the same as -posix. */
shell_name = base_pathname (argv[0]);
if (*shell_name == '-')
shell_name++;
if (shell_name[0] == 's' && shell_name[1] == 'h' && !shell_name[2])
act_like_sh++;
yydebug = 0;
shell_environment = env;
shell_name = argv[0];
dollar_vars[0] = savestring (shell_name);
if (*shell_name == '-')
{
shell_name++;
login_shell++;
}
#if defined (JOB_CONTROL)
if (act_like_sh)
job_control = 0; /* XXX - not posix */
#endif /* JOB_CONTROL */
shell_start_time = NOW; /* NOW now defined in general.h */
/* A program may start an interactive shell with
"execl ("/bin/bash", "-", NULL)".
If so, default the name of this shell to our name. */
if (!shell_name || !*shell_name || (shell_name[0] == '-' && !shell_name[1]))
shell_name = "bash";
/* Parse argument flags from the input line. */
/* Find full word arguments first. */
while ((arg_index != argc) && *(argv[arg_index]) == '-')
{
for (i = 0; long_args[i].name; i++)
{
if (STREQ (&(argv[arg_index][1]), long_args[i].name))
{
if (long_args[i].type == Int)
*long_args[i].int_value = 1;
else
{
if (!argv[++arg_index])
{
report_error ("option `%s' expected an argument",
long_args[i].name);
exit (1);
}
else
*long_args[i].char_value = argv[arg_index];
}
goto handle_next_arg;
}
}
break; /* No such argument. Maybe flag arg. */
handle_next_arg:
arg_index++;
}
/* If we're in a strict Posix.2 mode, turn on interactive comments. */
if (posixly_correct)
interactive_comments = 1;
/* If user supplied the "-login" flag, then set and invert LOGIN_SHELL. */
if (make_login_shell)
{
login_shell++;
login_shell = -login_shell;
}
/* All done with full word options; do standard shell option parsing.*/
this_command_name = shell_name; /* for error reporting */
while (arg_index != argc && argv[arg_index] &&
(*argv[arg_index] == '-' || *argv[arg_index] == '+'))
{
/* There are flag arguments, so parse them. */
int arg_character, on_or_off, next_arg;
char *o_option, *arg_string;
i = 1;
next_arg = arg_index + 1;
arg_string = argv[arg_index];
on_or_off = arg_string[0];
/* A single `-' signals the end of options. From the 4.3 BSD sh.
An option `--' means the same thing; this is the standard
getopt(3) meaning. */
if (arg_string[0] == '-' &&
(arg_string[1] == '\0' ||
(arg_string[1] == '-' && arg_string[2] == '\0')))
{
arg_index++;
break;
}
while (arg_character = arg_string[i++])
{
switch (arg_character)
{
case 'c':
want_pending_command = 1;
break;
case 's':
read_from_stdin = 1;
break;
case 'o':
o_option = argv[next_arg];
if (!o_option)
{
list_minus_o_opts ();
break;
}
if (set_minus_o_option (on_or_off, o_option) != EXECUTION_SUCCESS)
exit (1);
next_arg++;
break;
default:
if (change_flag (arg_character, on_or_off) == FLAG_ERROR)
{
report_error ("%c%c: bad option", on_or_off, arg_character);
exit (1);
}
}
}
/* Can't do just a simple increment anymore -- what about
"bash -abouo emacs ignoreeof -hP"? */
arg_index = next_arg;
}
/* Need to get the argument to a -c option processed in the
above loop. The next arg is a command to execute, and the
following args are $0...$n respectively. */
if (want_pending_command)
{
local_pending_command = argv[arg_index];
if (!local_pending_command)
{
report_error ("`-c' requires an argument");
exit (1);
}
arg_index++;
}
this_command_name = (char *)NULL;
/* First, let the outside world know about our interactive status.
A shell is interactive if the `-i' flag was given, or if all of
the following conditions are met:
no -c command
no arguments remaining or the -s flag given
standard input is a terminal
standard output is a terminal
Refer to Posix.2, the description of the `sh' utility. */
if (forced_interactive || /* -i flag */
(!local_pending_command && /* No -c command and ... */
((arg_index == argc) || /* no remaining args or... */
read_from_stdin) && /* -s flag with args, and */
isatty (fileno (stdin)) && /* Input is a terminal and */
isatty (fileno (stdout)))) /* output is a terminal. */
{
interactive_shell = startup_state = interactive = 1;
}
else
{
#if defined (HISTORY)
# if defined (BANG_HISTORY)
history_expansion = 0;
# endif
remember_on_history = 0;
#endif /* HISTORY */
interactive_shell = startup_state = interactive = 0;
no_line_editing = 1;
#if defined (JOB_CONTROL)
job_control = 0;
#endif /* JOB_CONTROL */
}
#define CLOSE_FDS_AT_LOGIN
#if defined (CLOSE_FDS_AT_LOGIN)
/*
* Some systems have the bad habit of starting login shells with lots of open
* file descriptors. For instance, most systems that have picked up the
* pre-4.0 Sun YP code leave a file descriptor open each time you call one
* of the getpw* functions, and it's set to be open across execs. That
* means one for login, one for xterm, one for shelltool, etc.
*/
if (login_shell && interactive_shell)
{
for (i = 3; i < 20; i++)
close (i);
}
#endif /* CLOSE_FDS_AT_LOGIN */
/* From here on in, the shell must be a normal functioning shell.
Variables from the environment are expected to be set, etc. */
shell_initialize ();
if (interactive_shell)
{
char *term = getenv ("TERM");
no_line_editing |= term && (STREQ (term, "emacs"));
}
top_level_arg_index = arg_index;
if (!quiet && do_version)
show_shell_version ();
/* Give this shell a place to longjmp to before executing the
startup files. This allows users to press C-c to abort the
lengthy startup. */
{
int code;
code = setjmp (top_level);
if (code)
{
if (code == EXITPROG)
goto exit_shell;
else
locally_skip_execution++;
}
}
arg_index = top_level_arg_index;
/* Execute the start-up scripts. */
if (!interactive_shell)
{
makunbound ("PS1", shell_variables);
makunbound ("PS2", shell_variables);
interactive = 0;
}
else
{
change_flag ('i', FLAG_ON);
interactive = 1;
}
if (!locally_skip_execution)
run_startup_files ();
#if defined (RESTRICTED_SHELL)
/* I turn on the restrictions afterwards because it is explictly
stated in the POSIX spec that PATH cannot be set in a restricted
shell, except in .profile. */
maybe_make_restricted (shell_name);
#endif /* RESTRICTED_SHELL */
if (local_pending_command)
{
/* Bind remaining args to $0 ... $n */
WORD_LIST *args = (WORD_LIST *)NULL;
while (arg_index != argc)
args = make_word_list (make_word (argv[arg_index++]), args);
if (args)
{
args = REVERSE_LIST (args, WORD_LIST *);
/* Posix.2 4.56.3 says that the first argument after
sh -c command becomes $0, and the rest of the arguments
are bound to $1 ... $N. */
shell_name = savestring (args->word->word); /* XXX */
dollar_vars[0] = savestring (args->word->word);
remember_args (args->next, 1);
dispose_words (args);
}
startup_state = 2;
#if defined (ONESHOT)
run_one_command (local_pending_command);
goto exit_shell;
#else /* ONESHOT */
with_input_from_string (local_pending_command, "-c");
goto read_and_execute;
#endif /* !ONESHOT */
}
/* Do the things that should be done only for interactive shells. */
if (interactive_shell)
{
/* Set up for checking for presence of mail. */
remember_mail_dates ();
reset_mail_timer ();
#if defined (HISTORY)
/* Initialize the interactive history stuff. */
if (!shell_initialized)
load_history ();
#endif /* HISTORY */
/* Initialize terminal state for interactive shells after the
.bash_profile and .bashrc are interpreted. */
get_tty_state ();
}
/* Get possible input filename. */
if ((arg_index != argc) && !read_from_stdin)
{
int fd;
char *filename;
free (dollar_vars[0]);
dollar_vars[0] = savestring (argv[arg_index]);
filename = savestring (argv[arg_index]);
fd = open (filename, O_RDONLY);
if ((fd < 0) && (errno == ENOENT) && (absolute_program (filename) == 0))
{
char *path_filename;
/* If it's not in the current directory, try looking through PATH
for it. */
path_filename = find_path_file (argv[arg_index]);
if (path_filename)
{
free (filename);
filename = path_filename;
fd = open (filename, O_RDONLY);
}
}
arg_index++;
if (fd < 0)
{
file_error (filename);
exit (1);
}
/* Only do this with file descriptors we can seek on. */
if (lseek (fd, 0L, 1) != -1)
{
unsigned char sample[80];
int sample_len;
/* Check to see if the `file' in `bash file' is a binary file
according to the same tests done by execute_simple_command (),
and report an error and exit if it is. */
sample_len = read (fd, sample, sizeof (sample));
if (sample_len > 0 && (check_binary_file (sample, sample_len)))
{
report_error ("%s: cannot execute binary file", filename);
exit (EX_BINARY_FILE);
}
/* Now rewind the file back to the beginning. */
lseek (fd, 0L, 0);
}
#if defined (BUFFERED_INPUT)
default_buffered_input = fd;
if (default_buffered_input == -1)
{
file_error (filename);
exit (127);
}
SET_CLOSE_ON_EXEC (default_buffered_input);
#else /* !BUFFERED_INPUT */
/* Open the script. But try to move the file descriptor to a randomly
large one, in the hopes that any descriptors used by the script will
not match with ours. */
{
int script_fd, nfds;
nfds = getdtablesize ();
if (nfds <= 0)
nfds = 20;
if (nfds > 256)
nfds = 256;
script_fd = dup2 (fd, nfds - 1);
if (script_fd)
{
close (fd);
fd = script_fd;
}
}
default_input = fdopen (fd, "r");
if (!default_input)
{
file_error (filename);
exit (127);
}
SET_CLOSE_ON_EXEC (fd);
if (fileno (default_input) != fd)
SET_CLOSE_ON_EXEC (fileno (default_input));
#endif /* !BUFFERED_INPUT */
if (!interactive_shell || (!isatty (fd)))
{
#if defined (HISTORY)
# if defined (BANG_HISTORY)
history_expansion = 0;
# endif
remember_on_history = 0;
#endif /* HISTORY */
interactive = interactive_shell = 0;
no_line_editing = 1;
#if defined (JOB_CONTROL)
set_job_control (0);
#endif /* JOB_CONTROL */
}
else
{
/* I don't believe that this code is ever executed, even in
the presence of /dev/fd. */
dup2 (fd, 0);
close (fd);
fclose (default_input);
}
}
else if (!interactive)
/* In this mode, bash is reading a script from stdin, which is a
pipe or redirected file. */
#if defined (BUFFERED_INPUT)
default_buffered_input = fileno (stdin); /* == 0 */
#else
setbuf (default_input, (char *)NULL);
#endif /* !BUFFERED_INPUT */
/* Bind remaining args to $1 ... $n */
{
WORD_LIST *args = (WORD_LIST *)NULL;
while (arg_index != argc)
args = make_word_list (make_word (argv[arg_index++]), args);
args = REVERSE_LIST (args, WORD_LIST *);
remember_args (args, 1);
dispose_words (args);
}
#if defined (BUFFERED_INPUT)
if (!interactive)
unset_nodelay_mode (default_buffered_input);
else
unset_nodelay_mode (fileno (stdin));
#else
unset_nodelay_mode (fileno (stdin));
#endif /* !BUFFERED_INPUT */
/* with_input_from_stdin really means `with_input_from_readline' */
if (interactive && !no_line_editing)
with_input_from_stdin ();
else
#if defined (BUFFERED_INPUT)
{
if (!interactive)
with_input_from_buffered_stream (default_buffered_input, dollar_vars[0]);
else
with_input_from_stream (default_input, dollar_vars[0]);
}
#else /* !BUFFERED_INPUT */
with_input_from_stream (default_input, dollar_vars[0]);
#endif /* !BUFFERED_INPUT */
#if !defined (ONESHOT)
read_and_execute:
#endif /* !ONESHOT */
shell_initialized = 1;
/* Read commands until exit condition. */
reader_loop ();
exit_shell:
/* Do trap[0] if defined. */
if (signal_is_trapped (0))
last_command_exit_value = run_exit_trap ();
#if defined (PROCESS_SUBSTITUTION)
unlink_fifo_list ();
#endif /* PROCESS_SUBSTITUTION */
#if defined (HISTORY)
if (interactive_shell)
maybe_save_shell_history ();
#endif /* HISTORY */
#if defined (JOB_CONTROL)
/* If this shell is interactive, terminate all stopped jobs and
restore the original terminal process group. */
end_job_control ();
#endif /* JOB_CONTROL */
/* Always return the exit status of the last command to our parent. */
exit (last_command_exit_value);
}
#if !defined (SYS_PROFILE)
# define SYS_PROFILE "/etc/profile"
#endif /* !SYS_PROFILE */
/* Source the bash startup files. If POSIXLY_CORRECT is non-zero, we obey
the Posix.2 startup file rules: $ENV is expanded, and if the file it
names exists, that file is sourced. The Posix.2 rules are in effect
for both interactive and non-interactive shells (section 4.56.5.3) */
static void
run_startup_files ()
{
if (!posixly_correct)
{
if (login_shell)
{
/* We don't execute .bashrc for login shells. */
no_rc++;
if (no_profile == 0)
maybe_execute_file (SYS_PROFILE, 1);
}
if (login_shell && !no_profile)
{
if (act_like_sh)
maybe_execute_file ("~/.profile", 1);
else
{
if (maybe_execute_file ("~/.bash_profile", 1) == 0)
if (maybe_execute_file ("~/.bash_login", 1) == 0)
maybe_execute_file ("~/.profile", 1);
}
}
/* Execute ~/.bashrc for most shells. Never execute it if
ACT_LIKE_SH is set, or if NO_RC is set.
If the executable file "/usr/gnu/src/bash/foo" contains:
#!/usr/gnu/bin/bash
echo hello
then:
COMMAND EXECUTE BASHRC
--------------------------------
bash -c foo NO
bash foo NO
foo NO
rsh machine ls YES (for rsh, which calls `bash -c')
rsh machine foo YES (for shell started by rsh) NO (for foo!)
echo ls | bash NO
login NO
bash YES
*/
if (!act_like_sh && !no_rc &&
(interactive_shell || (isnetconn (fileno (stdin)) &&
local_pending_command)))
maybe_execute_file (bashrc_file, 1);
}
/* Try a TMB suggestion. If running a script, then execute the
file mentioned in the ENV variable. */
if (!privileged_mode && sourced_env++ == 0 && act_like_sh == 0 &&
(posixly_correct || !interactive_shell))
{
char *env_file = (char *)NULL;
if (!posixly_correct)
env_file = getenv ("BASH_ENV");
if (!env_file)
env_file = getenv ("ENV");
if (env_file && *env_file)
{
WORD_LIST *list;
char *expanded_file_name;
list = expand_string_unsplit (env_file, 1);
if (list)
{
expanded_file_name = string_list (list);
dispose_words (list);
if (expanded_file_name && *expanded_file_name)
maybe_execute_file (expanded_file_name, 1);
if (expanded_file_name)
free (expanded_file_name);
}
}
}
}
#if defined (RESTRICTED_SHELL)
/* Perhaps make this shell a `restricted' one, based on NAME.
If the basename of NAME is "rbash", then this shell is restricted.
In a restricted shell, PATH and SHELL are read-only and non-unsettable.
Do this also if `restricted' is already set to 1; maybe the shell was
started with -r. */
maybe_make_restricted (name)
char *name;
{
char *temp;
temp = base_pathname (shell_name);
if (restricted || (STREQ (temp, "rbash")))
{
set_var_read_only ("PATH");
non_unsettable ("PATH");
set_var_read_only ("SHELL");
non_unsettable ("SHELL");
restricted++;
}
}
#endif /* RESTRICTED_SHELL */
/* Try to execute the contents of FNAME. If FNAME doesn't exist,
that is not an error, but other kinds of errors are. A non-zero
FORCE_NONINTERACTIVE means to set the value of `interactive' to
0 so things like job control are disabled; the value is unchanged
otherwise. Returns -1 in the case of an error, 0 in the case that
the file was not found, and 1 if the file was found and executed. */
maybe_execute_file (fname, force_noninteractive)
char *fname;
int force_noninteractive;
{
jmp_buf old_return_catch;
int return_val, fd, tresult, old_interactive;
char *filename, *string;
struct stat file_info;
filename = tilde_expand (fname);
fd = open (filename, O_RDONLY);
if (fd < 0)
{
file_error_and_exit:
if (errno != ENOENT)
file_error (filename);
free (filename);
return ((errno == ENOENT) ? 0 : -1);
}
if (fstat (fd, &file_info) == -1)
goto file_error_and_exit;
if (S_ISDIR (file_info.st_mode))
{
internal_error ("%s: cannot execute directories", filename);
free (filename);
return -1;
}
string = (char *)xmalloc (1 + (int)file_info.st_size);
tresult = read (fd, string, file_info.st_size);
{
int tt = errno;
close (fd);
errno = tt;
}
if (tresult != file_info.st_size)
{
free (string);
goto file_error_and_exit;
}
string[file_info.st_size] = '\0';
return_catch_flag++;
xbcopy ((char *)return_catch, (char *)old_return_catch, sizeof (jmp_buf));
if (force_noninteractive)
{
old_interactive = interactive;
interactive = 0;
}
return_val = setjmp (return_catch);
/* If `return' was seen outside of a function, but in the script, then
force parse_and_execute () to clean up. */
if (return_val)
parse_and_execute_cleanup ();
else
tresult = parse_and_execute (string, filename, -1);
if (force_noninteractive)
interactive = old_interactive;
return_catch_flag--;
xbcopy ((char *)old_return_catch, (char *)return_catch, sizeof (jmp_buf));
free (filename);
return (1);
}
#if defined (ONESHOT)
/* Run one command, given as the argument to the -c option. Tell
parse_and_execute not to fork for a simple command. */
run_one_command (command)
char *command;
{
int code;
code = setjmp (top_level);
if (code != NOT_JUMPED)
{
#if defined (PROCESS_SUBSTITUTION)
unlink_fifo_list ();
#endif /* PROCESS_SUBSTITUTION */
switch (code)
{
/* Some kind of throw to top_level has occured. */
case FORCE_EOF:
return last_command_exit_value = 127;
case EXITPROG:
return last_command_exit_value;
case DISCARD:
return last_command_exit_value = 1;
default:
programming_error ("Bad jump %d", code);
}
}
return (parse_and_execute (savestring (command), "-c", -1));
}
#endif /* ONESHOT */
reader_loop ()
{
int our_indirection_level;
COMMAND *current_command = (COMMAND *)NULL;
our_indirection_level = ++indirection_level;
while (!EOF_Reached)
{
int code;
code = setjmp (top_level);
#if defined (PROCESS_SUBSTITUTION)
unlink_fifo_list ();
#endif /* PROCESS_SUBSTITUTION */
if (interactive_shell && signal_is_ignored (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 occured. */
case FORCE_EOF:
case EXITPROG:
current_command = (COMMAND *)NULL;
EOF_Reached = EOF;
goto exec_done;
case DISCARD:
/* Obstack free command elements, etc. */
if (current_command)
{
dispose_command (current_command);
current_command = (COMMAND *)NULL;
}
last_command_exit_value = 1;
break;
default:
programming_error ("Bad jump %d", code);
}
}
executing = 0;
dispose_used_env_vars ();
#if (defined (Ultrix) && defined (mips)) || !defined (HAVE_ALLOCA)
/* Attempt to reclaim memory allocated with alloca (). */
(void) alloca (0);
#endif
if (read_command () == 0)
{
if (global_command)
{
current_command = global_command;
current_command_number++;
/* POSIX spec: "-n: The shell reads commands but does
not execute them; this can be used to check for shell
script syntax errors. The shell ignores the -n option
for interactive shells. " */
if (interactive_shell || !read_but_dont_execute)
{
executing = 1;
execute_command (current_command);
}
exec_done:
if (current_command)
{
dispose_command (current_command);
current_command = (COMMAND *)NULL;
}
QUIT;
}
}
else
{
/* Parse error, maybe discard rest of stream if not interactive. */
if (!interactive)
EOF_Reached = EOF;
}
if (just_one_command)
EOF_Reached = EOF;
}
indirection_level--;
}
/* Return a string denoting what our indirection level is. */
static char indirection_string[100];
char *
indirection_level_string ()
{
register int i, j;
char *ps4;
indirection_string[0] = '\0';
ps4 = get_string_value ("PS4");
if (ps4 == 0 || *ps4 == '\0')
return (indirection_string);
ps4 = decode_prompt_string (ps4);
for (i = 0; *ps4 && i < indirection_level && i < 99; i++)
indirection_string[i] = *ps4;
for (j = 1; *ps4 && ps4[j] && i < 99; i++, j++)
indirection_string[i] = ps4[j];
indirection_string[i] = '\0';
free (ps4);
return (indirection_string);
}
static sighandler
alrm_catcher(i)
int i;
{
printf ("%ctimed out waiting for input: auto-logout\n", '\07');
longjmp (top_level, EXITPROG);
#if !defined (VOID_SIGHANDLER)
return (0);
#endif /* !VOID_SIGHANDLER */
}
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. */
if (interactive && bash_input.type != st_string)
{
char *command_to_execute;
command_to_execute = get_string_value ("PROMPT_COMMAND");
if (command_to_execute)
execute_prompt_command (command_to_execute);
}
current_command_line_count = 0;
r = yyparse ();
if (need_here_doc)
gather_here_documents ();
return (r);
}
read_command ()
{
SHELL_VAR *tmout_var = (SHELL_VAR *)NULL;
int tmout_len = 0, result;
SigHandler *old_alrm = (SigHandler *)NULL;
prompt_string_pointer = &ps1_prompt;
global_command = (COMMAND *)NULL;
/* Only do timeouts if interactive. */
if (interactive)
{
tmout_var = find_variable ("TMOUT");
if (tmout_var && tmout_var->value)
{
tmout_len = atoi (tmout_var->value);
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);
}
/* Cause STREAM to buffer lines as opposed to characters or blocks. */
static void
line_buffer_stream (stream)
FILE *stream;
{
/* If your machine doesn't have either of setlinebuf or setvbuf,
you can just comment out the buffering commands, and the shell
will still work. It will take more cycles, though. */
#if defined (HAVE_SETLINEBUF)
setlinebuf (stream);
#else
# if defined (_IOLBF)
# if defined (REVERSED_SETVBUF_ARGS)
setvbuf (stream, _IOLBF, (char *)NULL, BUFSIZ);
# else /* !REVERSED_SETVBUF_ARGS */
setvbuf (stream, (char *)NULL, _IOLBF, BUFSIZ);
# endif /* !REVERSED_SETVBUF_ARGS */
# endif /* _IOLBF */
#endif /* !HAVE_SETLINEBUF */
}
/* Do whatever is necessary to initialize the shell.
Put new initializations in here. */
static void
shell_initialize ()
{
/* Line buffer output for stderr and stdout. */
line_buffer_stream (stderr);
line_buffer_stream (stdout);
/* Sort the array of shell builtins so that the binary search in
find_shell_builtin () works correctly. */
initialize_shell_builtins ();
/* Initialize the trap signal handlers before installing our own
signal handlers. traps.c:restore_original_signals () is responsible
for restoring the original default signal handlers. That function
is called when we make a new child. */
initialize_traps ();
initialize_signals ();
/* Initialize current_user.name and current_host_name. */
{
struct passwd *entry = getpwuid (current_user.uid);
char hostname[256];
if (gethostname (hostname, 255) < 0)
current_host_name = "??host??";
else
current_host_name = savestring (hostname);
if (entry)
{
current_user.user_name = savestring (entry->pw_name);
if (entry->pw_shell && entry->pw_shell[0])
current_user.shell = savestring (entry->pw_shell);
else
current_user.shell = savestring ("/bin/sh");
current_user.home_dir = savestring (entry->pw_dir);
}
else
{
current_user.user_name = savestring ("I have no name!");
current_user.shell = savestring ("/bin/sh");
current_user.home_dir = savestring ("/");
}
endpwent ();
}
/* Initialize our interface to the tilde expander. */
tilde_initialize ();
/* Initialize internal and environment variables. */
initialize_shell_variables (shell_environment);
/* Initialize filename hash tables. */
initialize_filename_hashing ();
/* Initialize the data structures for storing and running jobs. */
initialize_jobs ();
/* Initialize input streams to null. */
initialize_bash_input ();
}
/* Function called by main () when it appears that the shell has already
had some initialization performed. This is supposed to reset the world
back to a pristine state, as if we had been exec'ed. */
static void
shell_reinitialize ()
{
/* The default shell prompts. */
primary_prompt = PPROMPT;
secondary_prompt = SPROMPT;
/* Things that get 1. */
current_command_number = 1;
/* We have decided that the ~/.bashrc file should not be executed
for the invocation of each shell script. If the variable $ENV
(or $BASH_ENV) is set, its value is used as the name of a file
to source. */
no_rc = no_profile = 1;
/* Things that get 0. */
login_shell = make_login_shell = interactive = executing = 0;
debugging = do_version = line_number = last_command_exit_value = 0;
forced_interactive = interactive_shell = subshell_environment = 0;
#if defined (HISTORY)
# if defined (BANG_HISTORY)
history_expansion = 0;
# endif
remember_on_history = 0;
#endif /* HISTORY */
#if defined (RESTRICTED_SHELL)
restricted = 0;
#endif /* RESTRICTED_SHELL */
/* Ensure that the default startup file is used. (Except that we don't
execute this file for reinitialized shells). */
bashrc_file = "~/.bashrc";
/* Delete all variables and functions. They will be reinitialized when
the environment is parsed. */
delete_all_variables (shell_variables);
delete_all_variables (shell_functions);
/* Pretend the PATH variable has changed. */
sv_path ("PATH");
}
static void
initialize_signals ()
{
initialize_terminating_signals ();
initialize_job_signals ();
#if defined (INITIALIZE_SIGLIST)
initialize_siglist ();
#endif
}
void
reinitialize_signals ()
{
initialize_terminating_signals ();
initialize_job_signals ();
}
/* A structure describing a signal that terminates the shell if not
caught. The orig_handler member is present so children can reset
these signals back to their original handlers. */
struct termsig {
int signum;
SigHandler *orig_handler;
};
#define NULL_HANDLER (SigHandler *)SIG_DFL
/* The list of signals that would terminate the shell if not caught.
We catch them, but just so that we can write the history file,
and so forth. */
static struct termsig terminating_signals[] = {
#ifdef SIGHUP
SIGHUP, NULL_HANDLER,
#endif
#ifdef SIGINT
SIGINT, NULL_HANDLER,
#endif
#ifdef SIGILL
SIGILL, NULL_HANDLER,
#endif
#ifdef SIGTRAP
SIGTRAP, NULL_HANDLER,
#endif
#ifdef SIGIOT
SIGIOT, NULL_HANDLER,
#endif
#ifdef SIGDANGER
SIGDANGER, NULL_HANDLER,
#endif
#ifdef SIGEMT
SIGEMT, NULL_HANDLER,
#endif
#ifdef SIGFPE
SIGFPE, NULL_HANDLER,
#endif
#ifdef SIGBUS
SIGBUS, NULL_HANDLER,
#endif
#ifdef SIGSEGV
SIGSEGV, NULL_HANDLER,
#endif
#ifdef SIGSYS
SIGSYS, NULL_HANDLER,
#endif
#ifdef SIGPIPE
SIGPIPE, NULL_HANDLER,
#endif
#ifdef SIGALRM
SIGALRM, NULL_HANDLER,
#endif
#ifdef SIGTERM
SIGTERM, NULL_HANDLER,
#endif
#ifdef SIGXCPU
SIGXCPU, NULL_HANDLER,
#endif
#ifdef SIGXFSZ
SIGXFSZ, NULL_HANDLER,
#endif
#ifdef SIGVTALRM
SIGVTALRM, NULL_HANDLER,
#endif
#ifdef SIGPROF
SIGPROF, NULL_HANDLER,
#endif
#ifdef SIGLOST
SIGLOST, NULL_HANDLER,
#endif
#ifdef SIGUSR1
SIGUSR1, NULL_HANDLER,
#endif
#ifdef SIGUSR2
SIGUSR2, NULL_HANDLER,
#endif
};
#define TERMSIGS_LENGTH (sizeof (terminating_signals) / sizeof (struct termsig))
#define XSIG(x) (terminating_signals[x].signum)
#define XHANDLER(x) (terminating_signals[x].orig_handler)
/* This function belongs here? */
sighandler
termination_unwind_protect (sig)
int sig;
{
if (sig == SIGINT && signal_is_trapped (SIGINT))
run_interrupt_trap ();
#if defined (HISTORY)
if (interactive_shell)
maybe_save_shell_history ();
#endif /* HISTORY */
#if defined (JOB_CONTROL)
if (interactive && sig == SIGHUP)
hangup_all_jobs ();
end_job_control ();
#endif /* JOB_CONTROL */
#if defined (PROCESS_SUBSTITUTION)
unlink_fifo_list ();
#endif /* PROCESS_SUBSTITUTION */
run_exit_trap ();
set_signal_handler (sig, SIG_DFL);
kill (getpid (), sig);
#if !defined (VOID_SIGHANDLER)
return (0);
#endif /* VOID_SIGHANDLER */
}
/* Initialize signals that will terminate the shell to do some
unwind protection. */
static void
initialize_terminating_signals ()
{
register int i;
/* The following code is to avoid an expensive call to
set_signal_handler () for each terminating_signals. Fortunately,
this is possible in Posix. Unfortunately, we have to call signal ()
on non-Posix systems for each signal in terminating_signals. */
#if defined (_POSIX_VERSION)
struct sigaction act, oact;
act.sa_handler = termination_unwind_protect;
act.sa_flags = 0;
sigemptyset (&act.sa_mask);
sigemptyset (&oact.sa_mask);
for (i = 0; i < TERMSIGS_LENGTH; i++)
sigaddset (&act.sa_mask, XSIG (i));
for (i = 0; i < TERMSIGS_LENGTH; i++)
{
sigaction (XSIG (i), &act, &oact);
terminating_signals[i].orig_handler = oact.sa_handler;
/* Don't do anything with signals that are ignored at shell entry
if the shell is not interactive. */
if (!interactive_shell && oact.sa_handler == SIG_IGN)
{
sigaction (XSIG (i), &oact, &act);
set_signal_ignored (XSIG (i));
}
}
#else /* !_POSIX_VERSION */
for (i = 0; i < TERMSIGS_LENGTH; i++)
{
terminating_signals[i].orig_handler =
set_signal_handler (XSIG (i), termination_unwind_protect);
/* Don't do anything with signals that are ignored at shell entry
if the shell is not interactive. */
if (!interactive_shell && terminating_signals[i].orig_handler == SIG_IGN)
{
set_signal_handler (XSIG (i), SIG_IGN);
set_signal_ignored (XSIG (i));
}
}
#endif /* !_POSIX_VERSION */
#if defined (JOB_CONTROL) || defined (_POSIX_VERSION)
/* All shells use the signal mask they inherit, and pass it along
to child processes. Children will never block SIGCHLD, though. */
sigemptyset (&top_level_mask);
sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &top_level_mask);
sigdelset (&top_level_mask, SIGCHLD);
#endif /* JOB_CONTROL || _POSIX_VERSION */
/* And, some signals that are specifically ignored by the shell. */
set_signal_handler (SIGQUIT, SIG_IGN);
if (interactive)
{
set_signal_handler (SIGINT, sigint_sighandler);
set_signal_handler (SIGTERM, SIG_IGN);
}
}
void
reset_terminating_signals ()
{
register int i;
#if defined (_POSIX_VERSION)
struct sigaction act;
act.sa_flags = 0;
sigemptyset (&act.sa_mask);
for (i = 0; i < TERMSIGS_LENGTH; i++)
{
/* Skip a signal if it's trapped or handled specially, because the
trap code will restore the correct value. */
if (signal_is_trapped (XSIG (i)) || signal_is_special (XSIG (i)))
continue;
act.sa_handler = XHANDLER (i);
sigaction (XSIG (i), &act, (struct sigaction *) NULL);
}
#else
for (i = 0; i < TERMSIGS_LENGTH; i++)
{
if (signal_is_trapped (XSIG (i)) || signal_is_special (XSIG (i)))
continue;
set_signal_handler (XSIG (i), XHANDLER (i));
}
#endif
}
#undef XSIG
#undef XHANDLER
/* What to do when we've been interrupted, and it is safe to handle it. */
void
throw_to_top_level ()
{
int print_newline = 0;
if (interrupt_state)
{
print_newline = 1;
interrupt_state--;
}
if (interrupt_state)
return;
last_command_exit_value |= 128;
/* Run any traps set on SIGINT. */
run_interrupt_trap ();
/* Cleanup string parser environment. */
while (parse_and_execute_level)
parse_and_execute_cleanup ();
#if defined (JOB_CONTROL)
give_terminal_to (shell_pgrp);
#endif /* JOB_CONTROL */
#if defined (JOB_CONTROL) || defined (_POSIX_VERSION)
sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL);
#endif
reset_parser ();
#if defined (READLINE)
if (interactive)
bashline_reinitialize ();
#endif /* READLINE */
#if defined (PROCESS_SUBSTITUTION)
unlink_fifo_list ();
#endif /* PROCESS_SUBSTITUTION */
run_unwind_protects ();
loop_level = continuing = breaking = 0;
return_catch_flag = 0;
if (interactive && print_newline)
{
fflush (stdout);
fprintf (stderr, "\n");
fflush (stderr);
}
/* An interrupted `wait' command in a script does not exit the script. */
if (interactive || (interactive_shell && !shell_initialized) ||
(print_newline && signal_is_trapped (SIGINT)))
longjmp (top_level, DISCARD);
else
longjmp (top_level, EXITPROG);
}
/* When non-zero, we throw_to_top_level (). */
int interrupt_immediately = 0;
/* What we really do when SIGINT occurs. */
sighandler
sigint_sighandler (sig)
int sig;
{
#if defined (USG) && !defined (_POSIX_VERSION)
set_signal_handler (sig, sigint_sighandler);
#endif
/* interrupt_state needs to be set for the stack of interrupts to work
right. Should it be set unconditionally? */
if (!interrupt_state)
interrupt_state++;
if (interrupt_immediately)
{
interrupt_immediately = 0;
throw_to_top_level ();
}
#if !defined (VOID_SIGHANDLER)
return (0);
#endif /* VOID_SIGHANDLER */
}
/* Give version information about this shell. */
char *
shell_version_string ()
{
static char tt[16] = { '\0' };
if (!tt[0])
sprintf (tt, "%s.%d(%d)", dist_version, patch_level, build_version);
return tt;
}
void
show_shell_version ()
{
printf ("GNU %s, version %s\n", base_pathname (shell_name),
shell_version_string ());
}
#if !defined (USG) && defined (ENOTSOCK)
# if !defined (HAVE_SOCKETS)
# define HAVE_SOCKETS
# endif
#endif
#if defined (HAVE_SOCKETS)
#include <sys/socket.h>
#endif
/* Is FD a socket or network connection? */
static int
isnetconn (fd)
int fd;
{
#if defined (USGr4) || defined (USGr4_2)
/* Sockets on SVR4 and SVR4.2 are character special (streams) devices. */
struct stat sb;
if (fstat (fd, &sb) < 0)
return (0);
return (S_ISCHR (sb.st_mode));
#else /* !USGr4 && !USGr4_2 */
# if defined (HAVE_SOCKETS)
int rv, l;
struct sockaddr sa;
l = sizeof(sa);
rv = getpeername(0, &sa, &l);
return ((rv < 0 && errno == ENOTSOCK) ? 0 : 1);
# else /* !HAVE_SOCKETS */
# if defined (S_ISSOCK)
struct stat sb;
if (fstat (fd, &sb) < 0)
return (0);
return (S_ISSOCK (sb.st_mode));
# else /* !S_ISSOCK */
return (0);
# endif /* !S_ISSOCK */
# endif /* !HAVE_SOCKETS */
#endif /* !USGr4 && !USGr4_2 */
}
Reference in a new issue Copy permalink