58a54fbd5
Denys Vlasenko
2025-08-03
Subject
hush: disentangle interactiveness/job_control setup code
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shell/hush.c+67 -79
| @@ -10790,100 +10790,86 @@ int hush_main(int argc, char **argv) | |
| /* 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 |
| + | * not -c 'CMD' |
| + | * not running a script (no arguments remaining, or -s flag given) |
| * standard input is a terminal | |
| * standard output is a terminal | |
| * Refer to Posix.2, the description of the 'sh' utility. | |
| */ | |
| - | #if ENABLE_HUSH_JOB |
| - | if (!G_reexeced_on_NOMMU |
| - | && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) |
| - | ) { |
| - | G_saved_tty_pgrp = tcgetpgrp(STDIN_FILENO); |
| - | debug_printf("saved_tty_pgrp:%d\n", G_saved_tty_pgrp); |
| - | if (G_saved_tty_pgrp < 0) |
| - | G_saved_tty_pgrp = 0; |
| - | |
| - | /* try to dup stdin to high fd#, >= 255 */ |
| - | G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, 254); |
| - | if (G_interactive_fd < 0) { |
| - | /* try to dup to any fd */ |
| - | G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, -1); |
| - | if (G_interactive_fd < 0) { |
| - | /* give up */ |
| - | G_interactive_fd = 0; |
| - | G_saved_tty_pgrp = 0; |
| - | } |
| - | } |
| - | } |
| - | debug_printf("interactive_fd:%d\n", G_interactive_fd); |
| - | if (G_interactive_fd) { |
| - | 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); |
| - | } |
| - | } |
| - | |
| - | /* Install more signal handlers */ |
| - | install_special_sighandlers(); |
| - | |
| - | if (G_saved_tty_pgrp) { |
| - | /* Set fatal signals to restore saved_tty_pgrp */ |
| - | install_fatal_sighandlers(); |
| - | /* 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, G.root_pid); |
| - | } |
| - | init_line_editing(); |
| - | } |
| - | #elif ENABLE_HUSH_INTERACTIVE |
| - | /* No job control compiled in, only prompt/line editing */ |
| + | #if ENABLE_HUSH_INTERACTIVE |
| if (!G_reexeced_on_NOMMU | |
| && isatty(STDIN_FILENO) && isatty(STDOUT_FILENO) | |
| ) { | |
| + | /* Try to dup stdin to high fd#, >= 255 */ |
| G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, 254); | |
| if (G_interactive_fd < 0) { | |
| - | /* try to dup to any fd */ |
| + | /* Try to dup to any fd */ |
| G_interactive_fd = dup_CLOEXEC(STDIN_FILENO, -1); | |
| if (G_interactive_fd < 0) | |
| - | /* give up */ |
| + | /* Give up */ |
| G_interactive_fd = 0; | |
| } | |
| + | debug_printf("interactive_fd:%d\n", G_interactive_fd); |
| if (G_interactive_fd) { | |
| + | // TODO? bash: |
| + | // if interactive but not a login shell, sources ~/.bashrc |
| + | // (--norc turns this off, --rcfile <file> overrides) |
| + | # if ENABLE_HUSH_JOB |
| + | /* Can we do job control? */ |
| + | G_saved_tty_pgrp = tcgetpgrp(G_interactive_fd); |
| + | debug_printf("saved_tty_pgrp:%d\n", G_saved_tty_pgrp); |
| + | if (G_saved_tty_pgrp < 0) |
| + | G_saved_tty_pgrp = 0; /* no */ |
| + | 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(); |
| + | if (G_saved_tty_pgrp == shell_pgrp) { |
| + | /* Often both pgrps here are set to our pid - but not always! |
| + | * Example: sh -c 'echo $$; hush; echo FIN' |
| + | * Here, the parent shell is not interactive, so it does NOT set up |
| + | * a separate process group for its children, and we (hush) initinally |
| + | * run in parent's process group (until we set up our own a few lines down). |
| + | */ |
| + | //bb_error_msg("process groups tty:%d hush:%d", G_saved_tty_pgrp, shell_pgrp); |
| + | break; |
| + | } |
| + | /* Send TTIN to ourself (should stop us) */ |
| + | kill(- shell_pgrp, SIGTTIN); |
| + | G_saved_tty_pgrp = tcgetpgrp(G_interactive_fd); |
| + | } |
| + | } |
| + | # endif |
| + | /* Install more signal handlers */ |
| install_special_sighandlers(); | |
| + | # if ENABLE_HUSH_JOB |
| + | if (G_saved_tty_pgrp) { |
| + | /* Set fatal signals to restore saved_tty_pgrp */ |
| + | install_fatal_sighandlers(); |
| + | /* (The if() is an optimization: can avoid two redundant syscalls) */ |
| + | if (G_saved_tty_pgrp != G.root_pid) { |
| + | /* 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, G.root_pid); |
| + | } |
| + | } |
| + | # endif |
| + | # if ENABLE_FEATURE_EDITING_FANCY_PROMPT |
| + | /* Set (but not export) PS1/2 unless already set */ |
| + | if (!get_local_var_value("PS1")) |
| + | set_local_var_from_halves("PS1", "\\w \\$ "); |
| + | if (!get_local_var_value("PS2")) |
| + | set_local_var_from_halves("PS2", "> "); |
| + | # endif |
| init_line_editing(); | |
| - | } |
| - | } |
| - | #else |
| - | /* We have interactiveness code disabled */ |
| - | #endif |
| - | /* bash: |
| - | * if interactive but not a login shell, sources ~/.bashrc |
| - | * (--norc turns this off, --rcfile <file> overrides) |
| - | */ |
| - | if (G_interactive_fd) { |
| - | #if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING_FANCY_PROMPT |
| - | /* Set (but not export) PS1/2 unless already set */ |
| - | if (!get_local_var_value("PS1")) |
| - | set_local_var_from_halves("PS1", "\\w \\$ "); |
| - | if (!get_local_var_value("PS2")) |
| - | set_local_var_from_halves("PS2", "> "); |
| - | #endif |
| - | if (!ENABLE_FEATURE_SH_EXTRA_QUIET) { |
| + | # if !ENABLE_FEATURE_SH_EXTRA_QUIET |
| /* note: ash and hush share this string */ | |
| printf("\n\n%s %s\n" | |
| IF_HUSH_HELP("Enter 'help' for a list of built-in commands.\n") | |
| @@ -10891,8 +10877,10 @@ int hush_main(int argc, char **argv) | |
| bb_banner, | |
| "hush - the humble shell" | |
| ); | |
| - | } |
| - | } |
| + | # endif |
| + | } /* if become interactive */ |
| + | } /* if on tty */ |
| + | #endif /* if INTERACTIVE is allowed by build config */ |
| parse_and_run_file(hfopen(NULL)); /* stdin */ | |