hush: make it possible to have interactive shell on non-ctty.

init=/bin/hush: shows prompt, history works, etc.

function                                             old     new   delta
hush_main                                            888     925     +37
block_signals                                        139     152     +13
builtin_fg_bg                                        284     293      +9
checkjobs_and_fg_shell                                35      41      +6
sigexit                                               65      66      +1
reset_traps_to_defaults                              165     164      -1
parse_stream                                        2200    2184     -16
run_list                                            2502    2475     -27
getpgid                                               35       -     -35
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 5/3 up/down: 66/-79)            Total: -13 bytes
This commit is contained in:
Denis Vlasenko 2009-04-27 23:29:14 +00:00
parent 42e4af3119
commit c8653f62f2

View File

@ -417,15 +417,26 @@ struct function {
/* "Globals" within this file */
/* Sorted roughly by size (smaller offsets == smaller code) */
struct globals {
/* interactive_fd != 0 means we are an interactive shell.
* If we are, then saved_tty_pgrp can also be != 0, meaning
* that controlling tty is available. With saved_tty_pgrp == 0,
* job control still works, but terminal signals
* (^C, ^Z, ^Y, ^\) won't work at all, and background
* process groups can only be created with "cmd &".
* With saved_tty_pgrp != 0, hush will use tcsetpgrp()
* to give tty to the foreground process group,
* and will take it back when the group is stopped (^Z)
* or killed (^C).
*/
#if ENABLE_HUSH_INTERACTIVE
/* 'interactive_fd' is a fd# open to ctty, if we have one
* _AND_ if we decided to act interactively */
int interactive_fd;
const char *PS1;
const char *PS2;
#define G_interactive_fd (G.interactive_fd)
# define G_interactive_fd (G.interactive_fd)
#else
#define G_interactive_fd 0
# define G_interactive_fd 0
#endif
#if ENABLE_FEATURE_EDITING
line_input_t *line_input_state;
@ -434,10 +445,9 @@ struct globals {
pid_t last_bg_pid;
#if ENABLE_HUSH_JOB
int run_list_level;
pid_t saved_tty_pgrp;
int last_jobid;
pid_t saved_tty_pgrp;
struct pipe *job_list;
struct pipe *toplevel_list;
#endif
smallint flag_SIGINT;
#if ENABLE_HUSH_LOOPS
@ -446,7 +456,7 @@ struct globals {
#if ENABLE_HUSH_FUNCTIONS
/* 0: outside of a function (or sourced file)
* -1: inside of a function, ok to use return builtin
* 1: return is invoked, skip all till end of func.
* 1: return is invoked, skip all till end of func
*/
smallint flag_return_in_progress;
#endif
@ -1089,12 +1099,16 @@ static void restore_G_args(save_arg_t *sv, char **argv)
*/
enum {
SPECIAL_INTERACTIVE_SIGS = 0
#if ENABLE_HUSH_JOB
| (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
| (1 << SIGHUP)
#endif
| (1 << SIGTERM)
| (1 << SIGINT)
| (1 << SIGHUP)
,
#if ENABLE_HUSH_JOB
SPECIAL_JOB_SIGS = 0
| (1 << SIGTTIN)
| (1 << SIGTTOU)
| (1 << SIGTSTP)
#endif
};
//static void SIGCHLD_handler(int sig UNUSED_PARAM)
@ -1122,7 +1136,7 @@ static void sigexit(int sig)
/* Careful: we can end up here after [v]fork. Do not restore
* tty pgrp then, only top-level shell process does that */
if (G_interactive_fd && getpid() == G.root_pid)
if (G.saved_tty_pgrp && getpid() == G.root_pid)
tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
/* Not a signal, just exit */
@ -3131,7 +3145,7 @@ static const char *get_cmdtext(struct pipe *pi)
len += strlen(*argv) + 1;
} while (*++argv);
p = xmalloc(len);
pi->cmdtext = p;// = xmalloc(len);
pi->cmdtext = p;
argv = pi->cmds[0].argv;
do {
len = strlen(*argv);
@ -3351,10 +3365,12 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
{
pid_t p;
int rcode = checkjobs(fg_pipe);
/* Job finished, move the shell to the foreground */
p = getpgid(0); /* pgid of our process */
debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
tcsetpgrp(G_interactive_fd, p);
if (G.saved_tty_pgrp) {
/* Job finished, move the shell to the foreground */
p = getpgrp(); /* our process group id */
debug_printf_jobs("fg'ing ourself: getpgrp()=%d\n", (int)p);
tcsetpgrp(G_interactive_fd, p);
}
return rcode;
}
#endif
@ -3606,7 +3622,10 @@ static int run_pipe(struct pipe *pi)
pgrp = pi->pgrp;
if (pgrp < 0) /* true for 1st process only */
pgrp = getpid();
if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
if (setpgid(0, pgrp) == 0
&& pi->followup != PIPE_BG
&& G.saved_tty_pgrp /* we have ctty */
) {
/* We do it in *every* child, not just first,
* to avoid races */
tcsetpgrp(G_interactive_fd, pgrp);
@ -4023,11 +4042,7 @@ static int run_list(struct pipe *pi)
check_and_run_traps(0);
#if ENABLE_HUSH_JOB
if (G.run_list_level == 1)
{
debug_printf_exec("insert_bg_job1\n");
insert_bg_job(pi);
debug_printf_exec("insert_bg_job2\n");
}
#endif
G.last_exitcode = rcode = EXIT_SUCCESS;
debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n");
@ -5896,8 +5911,11 @@ static void block_signals(int second_time)
unsigned mask;
mask = (1 << SIGQUIT);
if (G_interactive_fd)
if (G_interactive_fd) {
mask = (1 << SIGQUIT) | SPECIAL_INTERACTIVE_SIGS;
if (G.saved_tty_pgrp) /* we have ctty, job control sigs work */
mask |= SPECIAL_JOB_SIGS;
}
G.non_DFL_mask = mask;
if (!second_time)
@ -6179,52 +6197,55 @@ int hush_main(int argc, char **argv)
if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
debug_printf("saved_tty_pgrp:%d\n", G.saved_tty_pgrp);
//TODO: "interactive" and "have job control" are two different things.
//If tcgetpgrp fails here, "have job control" is false, but "interactive"
//should stay on! Currently, we mix these into one.
if (G.saved_tty_pgrp >= 0) {
/* try to dup stdin to high fd#, >= 255 */
G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
if (G.saved_tty_pgrp < 0)
G.saved_tty_pgrp = 0;
/* try to dup stdin to high fd#, >= 255 */
G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
if (G_interactive_fd < 0) {
/* try to dup to any fd */
G_interactive_fd = dup(STDIN_FILENO);
if (G_interactive_fd < 0) {
/* try to dup to any fd */
G_interactive_fd = dup(STDIN_FILENO);
if (G_interactive_fd < 0)
/* give up */
G_interactive_fd = 0;
/* give up */
G_interactive_fd = 0;
G.saved_tty_pgrp = 0;
}
// TODO: track & disallow any attempts of user
// to (inadvertently) close/redirect it
}
// TODO: track & disallow any attempts of user
// to (inadvertently) close/redirect G_interactive_fd
}
debug_printf("interactive_fd:%d\n", G_interactive_fd);
if (G_interactive_fd) {
pid_t shell_pgrp;
/* We are indeed interactive shell, and we will perform
* job control. Setting up for that. */
close_on_exec_on(G_interactive_fd);
/* If we were run as 'hush &', sleep until we are
* in the foreground (tty pgrp == our pgrp).
* If we get started under a job aware app (like bash),
* make sure we are now in charge so we don't fight over
* who gets the foreground */
while (1) {
shell_pgrp = getpgrp();
G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
if (G.saved_tty_pgrp == shell_pgrp)
break;
/* send TTIN to ourself (should stop us) */
kill(- shell_pgrp, SIGTTIN);
if (G.saved_tty_pgrp) {
/* If we were run as 'hush &', sleep until we are
* in the foreground (tty pgrp == our pgrp).
* If we get started under a job aware app (like bash),
* make sure we are now in charge so we don't fight over
* who gets the foreground */
while (1) {
pid_t shell_pgrp = getpgrp();
G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
if (G.saved_tty_pgrp == shell_pgrp)
break;
/* send TTIN to ourself (should stop us) */
kill(- shell_pgrp, SIGTTIN);
}
}
/* Block some signals */
block_signals(signal_mask_is_inited);
/* Set other signals to restore saved_tty_pgrp */
set_fatal_handlers();
/* Put ourselves in our own process group */
bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
/* Grab control of the terminal */
tcsetpgrp(G_interactive_fd, getpid());
if (G.saved_tty_pgrp) {
/* Set other signals to restore saved_tty_pgrp */
set_fatal_handlers();
/* Put ourselves in our own process group
* (bash, too, does this only if ctty is available) */
bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
/* Grab control of the terminal */
tcsetpgrp(G_interactive_fd, getpid());
}
/* -1 is special - makes xfuncs longjmp, not exit
* (we reset die_sleep = 0 whereever we [v]fork) */
enable_restore_tty_pgrp_on_exit(); /* sets die_sleep = -1 */
@ -6604,6 +6625,7 @@ static int builtin_fg_bg(char **argv)
if (!G_interactive_fd)
return EXIT_FAILURE;
/* If they gave us no args, assume they want the last backgrounded task */
if (!argv[1]) {
for (pi = G.job_list; pi; pi = pi->next) {
@ -6628,7 +6650,7 @@ static int builtin_fg_bg(char **argv)
found:
/* TODO: bash prints a string representation
* of job being foregrounded (like "sleep 1 | cat") */
if (argv[0][0] == 'f') {
if (argv[0][0] == 'f' && G.saved_tty_pgrp) {
/* Put the job into the foreground. */
tcsetpgrp(G_interactive_fd, pi->pgrp);
}