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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
parent
42e4af3119
commit
c8653f62f2
138
shell/hush.c
138
shell/hush.c
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@ -417,15 +417,26 @@ struct function {
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/* "Globals" within this file */
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/* Sorted roughly by size (smaller offsets == smaller code) */
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struct globals {
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/* interactive_fd != 0 means we are an interactive shell.
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* If we are, then saved_tty_pgrp can also be != 0, meaning
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* that controlling tty is available. With saved_tty_pgrp == 0,
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* job control still works, but terminal signals
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* (^C, ^Z, ^Y, ^\) won't work at all, and background
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* process groups can only be created with "cmd &".
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* With saved_tty_pgrp != 0, hush will use tcsetpgrp()
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* to give tty to the foreground process group,
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* and will take it back when the group is stopped (^Z)
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* or killed (^C).
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*/
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#if ENABLE_HUSH_INTERACTIVE
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/* 'interactive_fd' is a fd# open to ctty, if we have one
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* _AND_ if we decided to act interactively */
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int interactive_fd;
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const char *PS1;
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const char *PS2;
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#define G_interactive_fd (G.interactive_fd)
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# define G_interactive_fd (G.interactive_fd)
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#else
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#define G_interactive_fd 0
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# define G_interactive_fd 0
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#endif
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#if ENABLE_FEATURE_EDITING
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line_input_t *line_input_state;
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@ -434,10 +445,9 @@ struct globals {
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pid_t last_bg_pid;
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#if ENABLE_HUSH_JOB
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int run_list_level;
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pid_t saved_tty_pgrp;
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int last_jobid;
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pid_t saved_tty_pgrp;
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struct pipe *job_list;
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struct pipe *toplevel_list;
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#endif
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smallint flag_SIGINT;
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#if ENABLE_HUSH_LOOPS
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@ -446,7 +456,7 @@ struct globals {
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#if ENABLE_HUSH_FUNCTIONS
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/* 0: outside of a function (or sourced file)
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* -1: inside of a function, ok to use return builtin
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* 1: return is invoked, skip all till end of func.
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* 1: return is invoked, skip all till end of func
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*/
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smallint flag_return_in_progress;
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#endif
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@ -1089,12 +1099,16 @@ static void restore_G_args(save_arg_t *sv, char **argv)
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*/
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enum {
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SPECIAL_INTERACTIVE_SIGS = 0
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#if ENABLE_HUSH_JOB
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| (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
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| (1 << SIGHUP)
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#endif
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| (1 << SIGTERM)
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| (1 << SIGINT)
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| (1 << SIGHUP)
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,
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#if ENABLE_HUSH_JOB
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SPECIAL_JOB_SIGS = 0
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| (1 << SIGTTIN)
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| (1 << SIGTTOU)
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| (1 << SIGTSTP)
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#endif
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};
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//static void SIGCHLD_handler(int sig UNUSED_PARAM)
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@ -1122,7 +1136,7 @@ static void sigexit(int sig)
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/* Careful: we can end up here after [v]fork. Do not restore
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* tty pgrp then, only top-level shell process does that */
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if (G_interactive_fd && getpid() == G.root_pid)
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if (G.saved_tty_pgrp && getpid() == G.root_pid)
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tcsetpgrp(G_interactive_fd, G.saved_tty_pgrp);
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/* Not a signal, just exit */
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@ -3131,7 +3145,7 @@ static const char *get_cmdtext(struct pipe *pi)
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len += strlen(*argv) + 1;
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} while (*++argv);
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p = xmalloc(len);
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pi->cmdtext = p;// = xmalloc(len);
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pi->cmdtext = p;
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argv = pi->cmds[0].argv;
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do {
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len = strlen(*argv);
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@ -3351,10 +3365,12 @@ static int checkjobs_and_fg_shell(struct pipe* fg_pipe)
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{
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pid_t p;
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int rcode = checkjobs(fg_pipe);
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/* Job finished, move the shell to the foreground */
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p = getpgid(0); /* pgid of our process */
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debug_printf_jobs("fg'ing ourself: getpgid(0)=%d\n", (int)p);
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tcsetpgrp(G_interactive_fd, p);
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if (G.saved_tty_pgrp) {
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/* Job finished, move the shell to the foreground */
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p = getpgrp(); /* our process group id */
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debug_printf_jobs("fg'ing ourself: getpgrp()=%d\n", (int)p);
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tcsetpgrp(G_interactive_fd, p);
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}
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return rcode;
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}
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#endif
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@ -3606,7 +3622,10 @@ static int run_pipe(struct pipe *pi)
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pgrp = pi->pgrp;
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if (pgrp < 0) /* true for 1st process only */
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pgrp = getpid();
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if (setpgid(0, pgrp) == 0 && pi->followup != PIPE_BG) {
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if (setpgid(0, pgrp) == 0
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&& pi->followup != PIPE_BG
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&& G.saved_tty_pgrp /* we have ctty */
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) {
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/* We do it in *every* child, not just first,
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* to avoid races */
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tcsetpgrp(G_interactive_fd, pgrp);
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@ -4023,11 +4042,7 @@ static int run_list(struct pipe *pi)
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check_and_run_traps(0);
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#if ENABLE_HUSH_JOB
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if (G.run_list_level == 1)
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{
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debug_printf_exec("insert_bg_job1\n");
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insert_bg_job(pi);
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debug_printf_exec("insert_bg_job2\n");
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}
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#endif
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G.last_exitcode = rcode = EXIT_SUCCESS;
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debug_printf_exec(": cmd&: exitcode EXIT_SUCCESS\n");
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@ -5896,8 +5911,11 @@ static void block_signals(int second_time)
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unsigned mask;
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mask = (1 << SIGQUIT);
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if (G_interactive_fd)
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if (G_interactive_fd) {
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mask = (1 << SIGQUIT) | SPECIAL_INTERACTIVE_SIGS;
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if (G.saved_tty_pgrp) /* we have ctty, job control sigs work */
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mask |= SPECIAL_JOB_SIGS;
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}
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G.non_DFL_mask = mask;
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if (!second_time)
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@ -6179,52 +6197,55 @@ int hush_main(int argc, char **argv)
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if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
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G.saved_tty_pgrp = tcgetpgrp(STDIN_FILENO);
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debug_printf("saved_tty_pgrp:%d\n", G.saved_tty_pgrp);
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//TODO: "interactive" and "have job control" are two different things.
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//If tcgetpgrp fails here, "have job control" is false, but "interactive"
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//should stay on! Currently, we mix these into one.
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if (G.saved_tty_pgrp >= 0) {
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/* try to dup stdin to high fd#, >= 255 */
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G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
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if (G.saved_tty_pgrp < 0)
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G.saved_tty_pgrp = 0;
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/* try to dup stdin to high fd#, >= 255 */
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G_interactive_fd = fcntl(STDIN_FILENO, F_DUPFD, 255);
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if (G_interactive_fd < 0) {
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/* try to dup to any fd */
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G_interactive_fd = dup(STDIN_FILENO);
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if (G_interactive_fd < 0) {
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/* try to dup to any fd */
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G_interactive_fd = dup(STDIN_FILENO);
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if (G_interactive_fd < 0)
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/* give up */
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G_interactive_fd = 0;
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/* give up */
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G_interactive_fd = 0;
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G.saved_tty_pgrp = 0;
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}
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// TODO: track & disallow any attempts of user
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// to (inadvertently) close/redirect it
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}
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// TODO: track & disallow any attempts of user
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// to (inadvertently) close/redirect G_interactive_fd
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}
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debug_printf("interactive_fd:%d\n", G_interactive_fd);
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if (G_interactive_fd) {
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pid_t shell_pgrp;
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/* We are indeed interactive shell, and we will perform
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* job control. Setting up for that. */
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close_on_exec_on(G_interactive_fd);
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/* If we were run as 'hush &', sleep until we are
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* in the foreground (tty pgrp == our pgrp).
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* If we get started under a job aware app (like bash),
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* make sure we are now in charge so we don't fight over
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* who gets the foreground */
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while (1) {
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shell_pgrp = getpgrp();
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G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
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if (G.saved_tty_pgrp == shell_pgrp)
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break;
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/* send TTIN to ourself (should stop us) */
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kill(- shell_pgrp, SIGTTIN);
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if (G.saved_tty_pgrp) {
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/* If we were run as 'hush &', sleep until we are
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* in the foreground (tty pgrp == our pgrp).
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* If we get started under a job aware app (like bash),
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* make sure we are now in charge so we don't fight over
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* who gets the foreground */
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while (1) {
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pid_t shell_pgrp = getpgrp();
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G.saved_tty_pgrp = tcgetpgrp(G_interactive_fd);
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if (G.saved_tty_pgrp == shell_pgrp)
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break;
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/* send TTIN to ourself (should stop us) */
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kill(- shell_pgrp, SIGTTIN);
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}
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}
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/* Block some signals */
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block_signals(signal_mask_is_inited);
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/* Set other signals to restore saved_tty_pgrp */
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set_fatal_handlers();
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/* Put ourselves in our own process group */
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bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
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/* Grab control of the terminal */
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tcsetpgrp(G_interactive_fd, getpid());
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if (G.saved_tty_pgrp) {
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/* Set other signals to restore saved_tty_pgrp */
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set_fatal_handlers();
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/* Put ourselves in our own process group
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* (bash, too, does this only if ctty is available) */
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bb_setpgrp(); /* is the same as setpgid(our_pid, our_pid); */
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/* Grab control of the terminal */
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tcsetpgrp(G_interactive_fd, getpid());
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}
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/* -1 is special - makes xfuncs longjmp, not exit
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* (we reset die_sleep = 0 whereever we [v]fork) */
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enable_restore_tty_pgrp_on_exit(); /* sets die_sleep = -1 */
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@ -6604,6 +6625,7 @@ static int builtin_fg_bg(char **argv)
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if (!G_interactive_fd)
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return EXIT_FAILURE;
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/* If they gave us no args, assume they want the last backgrounded task */
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if (!argv[1]) {
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for (pi = G.job_list; pi; pi = pi->next) {
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@ -6628,7 +6650,7 @@ static int builtin_fg_bg(char **argv)
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found:
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/* TODO: bash prints a string representation
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* of job being foregrounded (like "sleep 1 | cat") */
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if (argv[0][0] == 'f') {
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if (argv[0][0] == 'f' && G.saved_tty_pgrp) {
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/* Put the job into the foreground. */
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tcsetpgrp(G_interactive_fd, pi->pgrp);
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}
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