1 files changed, 249 insertions, 219 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 0b2bc01f5..09ab6ebc0 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -392,6 +392,8 @@
 
 /* Build knobs */
 #define LEAK_HUNTING 0
+#define LEAK_PRINTF(...) fdprintf(__VA_ARGS__)
+//#define LEAK_PRINTF(...) do { if (ptr_to_globals && G.root_pid == getpid()) fdprintf(__VA_ARGS__); } while (0)
 #define BUILD_AS_NOMMU 0
 /* Enable/disable sanity checks. Ok to enable in production,
  * only adds a bit of bloat. Set to >1 to get non-production level verbosity.
@@ -930,6 +932,12 @@ struct globals {
 # define G_flag_return_in_progress 0
 #endif
         smallint exiting; /* used to prevent EXIT trap recursion */
+#if !BB_MMU
+        smallint reexeced_on_NOMMU;
+# define G_reexeced_on_NOMMU (G.reexeced_on_NOMMU)
+#else
+# define G_reexeced_on_NOMMU 0
+#endif
         /* These support $? */
         smalluint last_exitcode;
         smalluint expand_exitcode;
@@ -1352,30 +1360,67 @@ static void debug_print_strings(const char *prefix, char **vv)
 static void *xxmalloc(int lineno, size_t size)
 {
         void *ptr = xmalloc((size + 0xff) & ~0xff);
-        fdprintf(2, "line %d: malloc %p\n", lineno, ptr);
+        LEAK_PRINTF(2, "line %d: malloc %p\n", lineno, ptr);
+        return ptr;
+}
+static void *xxzalloc(int lineno, size_t size)
+{
+        void *ptr = xzalloc((size + 0xff) & ~0xff);
+        LEAK_PRINTF(2, "line %d: zalloc %p\n", lineno, ptr);
         return ptr;
 }
 static void *xxrealloc(int lineno, void *ptr, size_t size)
 {
+        char *p = ptr;
         ptr = xrealloc(ptr, (size + 0xff) & ~0xff);
-        fdprintf(2, "line %d: realloc %p\n", lineno, ptr);
+        if (p != ptr)
+                LEAK_PRINTF(2, "line %d: realloc %p\n", lineno, ptr);
+        return ptr;
+}
+static void *xxrealloc_getcwd_or_warn(int lineno, char *ptr)
+{
+        char *p = ptr;
+        ptr = xrealloc_getcwd_or_warn(ptr);
+        if (p != ptr)
+                LEAK_PRINTF(2, "line %d: xrealloc_getcwd_or_warn %p\n", lineno, ptr);
         return ptr;
 }
 static char *xxstrdup(int lineno, const char *str)
 {
         char *ptr = xstrdup(str);
-        fdprintf(2, "line %d: strdup %p\n", lineno, ptr);
+        LEAK_PRINTF(2, "line %d: strdup %p\n", lineno, ptr);
+        return ptr;
+}
+static char *xxstrndup(int lineno, const char *str, size_t n)
+{
+        char *ptr = xstrndup(str, n);
+        LEAK_PRINTF(2, "line %d: strndup %p\n", lineno, ptr);
+        return ptr;
+}
+static char *xxasprintf(int lineno, const char *f, ...)
+{
+        char *ptr;
+        va_list args;
+        va_start(args, f);
+        if (vasprintf(&ptr, f, args) < 0)
+                bb_die_memory_exhausted();
+        va_end(args);
+        LEAK_PRINTF(2, "line %d: xasprintf %p\n", lineno, ptr);
         return ptr;
 }
 static void xxfree(void *ptr)
 {
-        fdprintf(2, "free %p\n", ptr);
+        LEAK_PRINTF(2, "free %p\n", ptr);
         free(ptr);
 }
-# define xmalloc(s)     xxmalloc(__LINE__, s)
-# define xrealloc(p, s) xxrealloc(__LINE__, p, s)
-# define xstrdup(s)     xxstrdup(__LINE__, s)
-# define free(p)        xxfree(p)
+# define xmalloc(s)        xxmalloc(__LINE__, s)
+# define xzalloc(s)        xxzalloc(__LINE__, s)
+# define xrealloc(p, s)    xxrealloc(__LINE__, p, s)
+# define xrealloc_getcwd_or_warn(p) xxrealloc_getcwd_or_warn(__LINE__, p)
+# define xstrdup(s)        xxstrdup(__LINE__, s)
+# define xstrndup(s, n)    xxstrndup(__LINE__, s, n)
+# define xasprintf(f, ...) xxasprintf(__LINE__, f, __VA_ARGS__)
+# define free(p)           xxfree(p)
 #endif
 
 /*
@@ -1929,7 +1974,7 @@ static void restore_G_args(save_arg_t *sv, char **argv)
  * "trap - SIGxxx":
  *    if sig is in special_sig_mask, set handler back to:
  *        record_pending_signo, or to IGN if it's a tty stop signal
- *    if sig is in fatal_sig_mask, set handler back to sigexit.
+ *    if sig is in fatal_sig_mask, set handler back to restore_ttypgrp_and_killsig_or__exit.
  *    else: set handler back to SIG_DFL
  * "trap 'cmd' SIGxxx":
  *    set handler to record_pending_signo.
@@ -2002,19 +2047,6 @@ static sighandler_t install_sighandler(int sig, sighandler_t handler)
         return old_sa.sa_handler;
 }
 
-static void hush_exit(int exitcode) NORETURN;
-
-static void restore_ttypgrp_and__exit(void) NORETURN;
-static void restore_ttypgrp_and__exit(void)
-{
-        /* xfunc has failed! die die die */
-        /* no EXIT traps, this is an escape hatch! */
-        G.exiting = 1;
-        hush_exit(xfunc_error_retval);
-}
-
-#if ENABLE_HUSH_JOB
-
 /* Needed only on some libc:
  * It was observed that on exit(), fgetc'ed buffered data
  * gets "unwound" via lseek(fd, -NUM, SEEK_CUR).
@@ -2028,26 +2060,20 @@ static void restore_ttypgrp_and__exit(void)
  * and in `cmd` handling.
  * If set as die_func(), this makes xfunc_die() exit via _exit(), not exit():
  */
-static void fflush_and__exit(void) NORETURN;
-static void fflush_and__exit(void)
+static NORETURN void fflush_and__exit(void)
 {
         fflush_all();
         _exit(xfunc_error_retval);
 }
 
-/* After [v]fork, in child: do not restore tty pgrp on xfunc death */
-# define disable_restore_tty_pgrp_on_exit() (die_func = fflush_and__exit)
-/* After [v]fork, in parent: restore tty pgrp on xfunc death */
-# define enable_restore_tty_pgrp_on_exit()  (die_func = restore_ttypgrp_and__exit)
-
+#if ENABLE_HUSH_JOB
 /* Restores tty foreground process group, and exits.
  * May be called as signal handler for fatal signal
  * (will resend signal to itself, producing correct exit state)
  * or called directly with -EXITCODE.
  * We also call it if xfunc is exiting.
  */
-static void sigexit(int sig) NORETURN;
-static void sigexit(int sig)
+static NORETURN void restore_ttypgrp_and_killsig_or__exit(int sig)
 {
         /* Careful: we can end up here after [v]fork. Do not restore
          * tty pgrp then, only top-level shell process does that */
@@ -2065,6 +2091,19 @@ static void sigexit(int sig)
 
         kill_myself_with_sig(sig); /* does not return */
 }
+
+static NORETURN void fflush_restore_ttypgrp_and__exit(void)
+{
+        /* xfunc has failed! die die die */
+        fflush_all();
+        restore_ttypgrp_and_killsig_or__exit(- xfunc_error_retval);
+}
+
+/* After [v]fork, in child: do not restore tty pgrp on xfunc death */
+# define disable_restore_tty_pgrp_on_exit() (die_func = fflush_and__exit)
+/* After [v]fork, in parent: restore tty pgrp on xfunc death */
+# define enable_restore_tty_pgrp_on_exit()  (die_func = fflush_restore_ttypgrp_and__exit)
+
 #else
 
 # define disable_restore_tty_pgrp_on_exit() ((void)0)
@@ -2081,7 +2120,7 @@ static sighandler_t pick_sighandler(unsigned sig)
 #if ENABLE_HUSH_JOB
                 /* is sig fatal? */
                 if (G_fatal_sig_mask & sigmask)
-                        handler = sigexit;
+                        handler = restore_ttypgrp_and_killsig_or__exit;
                 else
 #endif
                 /* sig has special handling? */
@@ -2101,11 +2140,15 @@ static sighandler_t pick_sighandler(unsigned sig)
 
 static const char* FAST_FUNC get_local_var_value(const char *name);
 
-/* Restores tty foreground process group, and exits. */
-static void hush_exit(int exitcode)
+/* Self-explanatory.
+ * Restores tty foreground process group too.
+ */
+static NORETURN void save_history_run_exit_trap_and_exit(int exitcode)
 {
 #if ENABLE_FEATURE_EDITING_SAVE_ON_EXIT
-        if (G.line_input_state) {
+        if (G.line_input_state
+         && getpid() == G.root_pid /* exits in subshells do not save history */
+        ) {
                 const char *hp;
 # if ENABLE_FEATURE_SH_HISTFILESIZE
 // in bash:
@@ -2155,7 +2198,7 @@ static void hush_exit(int exitcode)
 
         fflush_all();
 #if ENABLE_HUSH_JOB
-        sigexit(- (exitcode & 0xff));
+        restore_ttypgrp_and_killsig_or__exit(- (exitcode & 0xff));
 #else
         _exit(exitcode);
 #endif
@@ -2240,7 +2283,7 @@ static int check_and_run_traps(void)
                                 }
                         }
                         /* this restores tty pgrp, then kills us with SIGHUP */
-                        sigexit(SIGHUP);
+                        restore_ttypgrp_and_killsig_or__exit(SIGHUP);
                 }
 #endif
 #if ENABLE_HUSH_FAST
@@ -4625,6 +4668,11 @@ static int fetch_heredocs(o_string *as_string, struct pipe *pi, int heredoc_cnt,
 
                                         redir->rd_type = REDIRECT_HEREDOC2;
                                         /* redir->rd_dup is (ab)used to indicate <<- */
+                                        if (!redir->rd_filename) {
+                                                /* examples: "echo <<", "echo <<<", "echo <<>" */
+                                                syntax_error("missing here document terminator");
+                                                return -1;
+                                        }
                                         p = fetch_till_str(as_string, input,
                                                         redir->rd_filename, redir->rd_dup);
                                         if (!p) {
@@ -7384,11 +7432,6 @@ static void switch_off_special_sigs(unsigned mask)
 }
 
 #if BB_MMU
-/* never called */
-void re_execute_shell(char ***to_free, const char *s,
-                char *g_argv0, char **g_argv,
-                char **builtin_argv) NORETURN;
-
 static void reset_traps_to_defaults(void)
 {
         /* This function is always called in a child shell
@@ -7438,10 +7481,8 @@ static void reset_traps_to_defaults(void)
 
 #else /* !BB_MMU */
 
-static void re_execute_shell(char ***to_free, const char *s,
-                char *g_argv0, char **g_argv,
-                char **builtin_argv) NORETURN;
-static void re_execute_shell(char ***to_free, const char *s,
+static NORETURN void re_execute_shell(
+                char * *volatile * to_free, const char *s,
                 char *g_argv0, char **g_argv,
                 char **builtin_argv)
 {
@@ -7671,7 +7712,13 @@ static int generate_stream_from_string(const char *s, pid_t *pid_p)
         pid_t pid;
         int channel[2];
 # if !BB_MMU
-        char **to_free = NULL;
+        /* _volatile_ pointer to "char*".
+         * Or else compiler can peek from inside re_execute_shell()
+         * and see that this pointer is a local var (i.e. not globally visible),
+         * and decide to optimize out the store to it. Yes,
+         * it was seen in the wild.
+         */
+        char * *volatile to_free = NULL;
 # endif
 
         xpipe(channel);
@@ -7818,7 +7865,7 @@ static void setup_heredoc(struct redir_struct *redir)
         const char *heredoc = redir->rd_filename;
         char *expanded;
 #if !BB_MMU
-        char **to_free;
+        char * *volatile to_free;
 #endif
 
         expanded = NULL;
@@ -8293,7 +8340,7 @@ static const struct built_in_command *find_builtin(const char *name)
         return find_builtin_helper(name, bltins2, &bltins2[ARRAY_SIZE(bltins2)]);
 }
 
-#if ENABLE_HUSH_JOB && ENABLE_FEATURE_TAB_COMPLETION
+#if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_TAB_COMPLETION
 static const char * FAST_FUNC hush_command_name(int i)
 {
         if (/*i >= 0 && */ i < ARRAY_SIZE(bltins1)) {
@@ -8459,10 +8506,8 @@ static void unset_func(const char *name)
 #define exec_function(to_free, funcp, argv) \
         exec_function(funcp, argv)
 # endif
-static void exec_function(char ***to_free,
-                const struct function *funcp,
-                char **argv) NORETURN;
-static void exec_function(char ***to_free,
+static NORETURN void exec_function(
+                char * *volatile *to_free,
                 const struct function *funcp,
                 char **argv)
 {
@@ -8558,10 +8603,8 @@ static int run_function(const struct function *funcp, char **argv)
 #define exec_builtin(to_free, x, argv) \
         exec_builtin(to_free, argv)
 #endif
-static void exec_builtin(char ***to_free,
-                const struct built_in_command *x,
-                char **argv) NORETURN;
-static void exec_builtin(char ***to_free,
+static NORETURN void exec_builtin(
+                char * *volatile *to_free,
                 const struct built_in_command *x,
                 char **argv)
 {
@@ -8584,8 +8627,7 @@ static void exec_builtin(char ***to_free,
 #endif
 }
 
-static void execvp_or_die(char **argv) NORETURN;
-static void execvp_or_die(char **argv)
+static NORETURN void execvp_or_die(char **argv)
 {
         int e;
         debug_printf_exec("execing '%s'\n", argv[0]);
@@ -8706,10 +8748,8 @@ static void if_command_vV_print_and_exit(char opt_vV, char *cmd, const char *exp
  * The at_exit handlers apparently confuse the calling process,
  * in particular stdin handling. Not sure why? -- because of vfork! (vda)
  */
-static void pseudo_exec_argv(nommu_save_t *nommu_save,
-                char **argv, int assignment_cnt,
-                char **argv_expanded) NORETURN;
-static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
+static NORETURN NOINLINE void pseudo_exec_argv(
+                volatile nommu_save_t *nommu_save,
                 char **argv, int assignment_cnt,
                 char **argv_expanded)
 {
@@ -8735,7 +8775,8 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
 #if BB_MMU
         G.shadowed_vars_pp = NULL; /* "don't save, free them instead" */
 #else
-        G.shadowed_vars_pp = &nommu_save->old_vars;
+        /* cast away volatility */
+        G.shadowed_vars_pp = (struct variable **)&nommu_save->old_vars;
         G.var_nest_level++;
 #endif
         set_vars_and_save_old(new_env);
@@ -8862,10 +8903,8 @@ static NOINLINE void pseudo_exec_argv(nommu_save_t *nommu_save,
 
 /* Called after [v]fork() in run_pipe
  */
-static void pseudo_exec(nommu_save_t *nommu_save,
-                struct command *command,
-                char **argv_expanded) NORETURN;
-static void pseudo_exec(nommu_save_t *nommu_save,
+static NORETURN void pseudo_exec(
+                volatile nommu_save_t *nommu_save,
                 struct command *command,
                 char **argv_expanded)
 {
@@ -9750,8 +9789,7 @@ static NOINLINE int run_pipe(struct pipe *pi)
 
                         /* Stores to nommu_save list of env vars putenv'ed
                          * (NOMMU, on MMU we don't need that) */
-                        /* cast away volatility... */
-                        pseudo_exec((nommu_save_t*) &nommu_save, command, argv_expanded);
+                        pseudo_exec(&nommu_save, command, argv_expanded);
                         /* pseudo_exec() does not return */
                 }
 
@@ -10139,7 +10177,7 @@ static int run_list(struct pipe *pi)
                 if (rcode != 0 && G.o_opt[OPT_O_ERREXIT]) {
                         debug_printf_exec("ERREXIT:1 errexit_depth:%d\n", G.errexit_depth);
                         if (G.errexit_depth == 0)
-                                hush_exit(rcode);
+                                save_history_run_exit_trap_and_exit(rcode);
                 }
                 G.errexit_depth = sv_errexit_depth;
 
@@ -10213,6 +10251,53 @@ static int run_and_free_list(struct pipe *pi)
 /*
  * Initialization and main
  */
+#if ENABLE_HUSH_INTERACTIVE && ENABLE_FEATURE_EDITING
+static void init_line_editing(void)
+{
+        G.line_input_state = new_line_input_t(FOR_SHELL);
+# if ENABLE_FEATURE_TAB_COMPLETION
+        G.line_input_state->get_exe_name = hush_command_name;
+# endif
+# if EDITING_HAS_sh_get_var
+        G.line_input_state->sh_get_var = get_local_var_value;
+# endif
+# if ENABLE_HUSH_SAVEHISTORY && MAX_HISTORY > 0
+        {
+                const char *hp = get_local_var_value("HISTFILE");
+                if (!hp) {
+                        hp = get_local_var_value("HOME");
+                        if (hp) {
+                                hp = concat_path_file(hp, ".hush_history");
+                                /* Make HISTFILE set on exit (else history won't be saved) */
+                                set_local_var_from_halves("HISTFILE", hp);
+                        }
+                } else {
+                        hp = xstrdup(hp);
+                }
+                if (hp) {
+                        G.line_input_state->hist_file = hp;
+                }
+#  if ENABLE_FEATURE_SH_HISTFILESIZE
+                hp = get_local_var_value("HISTSIZE");
+                /* Using HISTFILESIZE above to limit max_history would be WRONG:
+                 * users may set HISTFILESIZE=0 in their profile scripts
+                 * to prevent _saving_ of history files, but still want to have
+                 * non-zero history limit for in-memory list.
+                 */
+// in bash, runtime history size is controlled by HISTSIZE (0=no history),
+// HISTFILESIZE controls on-disk history file size (in lines, 0=no history):
+                G.line_input_state->max_history = size_from_HISTFILESIZE(hp);
+// HISTFILESIZE: "The shell sets the default value to the value of HISTSIZE after reading any startup files."
+// HISTSIZE: "The shell sets the default value to 500 after reading any startup files."
+// (meaning: if the value wasn't set after startup files, the default value is set as described above)
+#  endif
+        }
+# endif
+}
+#else
+# define init_line_editing() ((void)0)
+#endif
+
 static void install_sighandlers(unsigned mask)
 {
         sighandler_t old_handler;
@@ -10351,7 +10436,6 @@ static int set_mode(int state, char mode, const char *o_opt)
 int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 int hush_main(int argc, char **argv)
 {
-        pid_t cached_getpid;
         enum {
                 OPT_login = (1 << 0),
         };
@@ -10364,6 +10448,11 @@ int hush_main(int argc, char **argv)
         struct variable *shell_ver;
 
         INIT_G();
+#if ENABLE_HUSH_JOB
+        die_func = fflush_restore_ttypgrp_and__exit;
+#else
+        die_func = fflush_and__exit;
+#endif
         if (EXIT_SUCCESS != 0) /* if EXIT_SUCCESS == 0, it is already done */
                 G.last_exitcode = EXIT_SUCCESS;
 #if !BB_MMU
@@ -10379,9 +10468,6 @@ int hush_main(int argc, char **argv)
                 _exit(0);
         }
         G.argv0_for_re_execing = argv[0];
-        if (G.argv0_for_re_execing[0] == '-')
-                /* reexeced hush should never be a login shell */
-                G.argv0_for_re_execing++;
 #endif
 #if ENABLE_HUSH_TRAP
 # if ENABLE_HUSH_FUNCTIONS
@@ -10394,9 +10480,8 @@ int hush_main(int argc, char **argv)
         G.count_SIGCHLD++; /* ensure it is != G.handled_SIGCHLD */
 #endif
 
-        cached_getpid = getpid();   /* for tcsetpgrp() during init */
-        G.root_pid = cached_getpid; /* for $PID  (NOMMU can override via -$HEXPID:HEXPPID:...) */
-        G.root_ppid = getppid();    /* for $PPID (NOMMU can override) */
+        G.root_pid = getpid();   /* for $PID  (NOMMU can override via -$HEXPID:HEXPPID:...) */
+        G.root_ppid = getppid(); /* for $PPID (NOMMU can override) */
 
         /* Deal with HUSH_VERSION */
         debug_printf_env("unsetenv '%s'\n", "HUSH_VERSION");
@@ -10479,27 +10564,24 @@ int hush_main(int argc, char **argv)
          * PS4='+ '
          */
 
+        /* Shell is non-interactive at first. We need to call
+         * install_special_sighandlers() if we are going to execute "sh <script>",
+         * "sh -c <cmds>" or login shell's /etc/profile and friends.
+         * If we later decide that we are interactive, we run
+         * install_special_sighandlers() in order to intercept more signals.
+         */
+        install_special_sighandlers();
+
 #if NUM_SCRIPTS > 0
         if (argc < 0) {
                 char *script = get_script_content(-argc - 1);
                 G.global_argv = argv;
                 G.global_argc = string_array_len(argv);
-                //install_special_sighandlers(); - needed?
                 parse_and_run_string(script);
                 goto final_return;
         }
 #endif
 
-        /* Initialize some more globals to non-zero values */
-        die_func = restore_ttypgrp_and__exit;
-
-        /* Shell is non-interactive at first. We need to call
-         * install_special_sighandlers() if we are going to execute "sh <script>",
-         * "sh -c <cmds>" or login shell's /etc/profile and friends.
-         * If we later decide that we are interactive, we run install_special_sighandlers()
-         * in order to intercept (more) signals.
-         */
-
         /* Parse options */
         /* http://www.opengroup.org/onlinepubs/9699919799/utilities/sh.html */
         flags = (argv[0] && argv[0][0] == '-') ? OPT_login : 0;
@@ -10563,6 +10645,7 @@ int hush_main(int argc, char **argv)
                 case '$': {
                         unsigned long long empty_trap_mask;
 
+                        G.reexeced_on_NOMMU = 1;
                         G.root_pid = bb_strtou(optarg, &optarg, 16);
                         optarg++;
                         G.root_ppid = bb_strtou(optarg, &optarg, 16);
@@ -10576,7 +10659,6 @@ int hush_main(int argc, char **argv)
                         empty_trap_mask = bb_strtoull(optarg, &optarg, 16);
                         if (empty_trap_mask != 0) {
                                 IF_HUSH_TRAP(int sig;)
-                                install_special_sighandlers();
 # if ENABLE_HUSH_TRAP
                                 G_traps = xzalloc(sizeof(G_traps[0]) * NSIG);
                                 for (sig = 1; sig < NSIG; sig++) {
@@ -10642,7 +10724,9 @@ int hush_main(int argc, char **argv)
         G.global_argv[0] = argv[0];
 
         /* If we are login shell... */
-        if (flags & OPT_login) {
+        if (!G_reexeced_on_NOMMU /* reexeced hush should never be a login shell */
+         && (flags & OPT_login)
+        ) {
                 const char *hp = NULL;
                 HFILE *input;
 
@@ -10650,7 +10734,6 @@ int hush_main(int argc, char **argv)
                 input = hfopen("/etc/profile");
  run_profile:
                 if (input != NULL) {
-                        install_special_sighandlers();
                         parse_and_run_file(input);
                         hfclose(input);
                 }
@@ -10687,8 +10770,6 @@ int hush_main(int argc, char **argv)
                  */
                 char *script;
 
-                install_special_sighandlers();
-
                 G.global_argc--;
                 G.global_argv++;
 #if !BB_MMU
@@ -10739,7 +10820,6 @@ int hush_main(int argc, char **argv)
                         bb_simple_perror_msg_and_die(G.global_argv[0]);
                 }
                 xfunc_error_retval = 1;
-                install_special_sighandlers();
                 parse_and_run_file(input);
 #if ENABLE_FEATURE_CLEAN_UP
                 hfclose(input);
@@ -10755,138 +10835,86 @@ 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 (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 */
+#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 */
+                        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);
+                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) initially
+ * 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);
+                                }
                         }
-                }
-
-                /* Install more signal handlers */
-                install_special_sighandlers();
-
-                if (G_saved_tty_pgrp) {
-                        /* Set other 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, cached_getpid);
-                }
-                enable_restore_tty_pgrp_on_exit();
-
-# if ENABLE_FEATURE_EDITING
-                G.line_input_state = new_line_input_t(FOR_SHELL);
-#  if ENABLE_FEATURE_TAB_COMPLETION
-                G.line_input_state->get_exe_name = hush_command_name;
-#  endif
-#  if EDITING_HAS_sh_get_var
-                G.line_input_state->sh_get_var = get_local_var_value;
-#  endif
 # endif
-# if ENABLE_HUSH_SAVEHISTORY && MAX_HISTORY > 0
-                {
-                        const char *hp = get_local_var_value("HISTFILE");
-                        if (!hp) {
-                                hp = get_local_var_value("HOME");
-                                if (hp) {
-                                        hp = concat_path_file(hp, ".hush_history");
-                                        /* Make HISTFILE set on exit (else history won't be saved) */
-                                        set_local_var_from_halves("HISTFILE", hp);
+                        /* 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);
                                 }
-                        } else {
-                                hp = xstrdup(hp);
                         }
-                        if (hp) {
-                                G.line_input_state->hist_file = hp;
-                        }
-#  if ENABLE_FEATURE_SH_HISTFILESIZE
-                        hp = get_local_var_value("HISTSIZE");
-                        /* Using HISTFILESIZE above to limit max_history would be WRONG:
-                         * users may set HISTFILESIZE=0 in their profile scripts
-                         * to prevent _saving_ of history files, but still want to have
-                         * non-zero history limit for in-memory list.
-                         */
-// in bash, runtime history size is controlled by HISTSIZE (0=no history),
-// HISTFILESIZE controls on-disk history file size (in lines, 0=no history):
-                        G.line_input_state->max_history = size_from_HISTFILESIZE(hp);
-// HISTFILESIZE: "The shell sets the default value to the value of HISTSIZE after reading any startup files."
-// HISTSIZE: "The shell sets the default value to 500 after reading any startup files."
-// (meaning: if the value wasn't set after startup files, the default value is set as described above)
-#  endif
-                }
 # endif
-        } else {
-                install_special_sighandlers();
-        }
-#elif ENABLE_HUSH_INTERACTIVE
-        /* No job control compiled in, only prompt/line editing */
-        if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
-                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;
-                }
-        }
-        install_special_sighandlers();
-#else
-        /* We have interactiveness code disabled */
-        install_special_sighandlers();
-#endif
-        /* bash:
-         * if interactive but not a login shell, sources ~/.bashrc
-         * (--norc turns this off, --rcfile <file> overrides)
-         */
+# 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();
 
-        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")
@@ -10894,13 +10922,15 @@ 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 */
 
  final_return:
-        hush_exit(G.last_exitcode);
+        save_history_run_exit_trap_and_exit(G.last_exitcode);
 }
 
 /*
@@ -11086,19 +11116,19 @@ static int FAST_FUNC builtin_exit(char **argv)
          * TODO: we can use G.exiting = -1 as indicator "last cmd was exit"
          */
 
-        /* note: EXIT trap is run by hush_exit */
+        /* note: EXIT trap is run by save_history_run_exit_trap_and_exit */
         argv = skip_dash_dash(argv);
         if (argv[0] == NULL) {
 #if ENABLE_HUSH_TRAP
                 if (G.pre_trap_exitcode >= 0) /* "exit" in trap uses $? from before the trap */
-                        hush_exit(G.pre_trap_exitcode);
+                        save_history_run_exit_trap_and_exit(G.pre_trap_exitcode);
 #endif
-                hush_exit(G.last_exitcode);
+                save_history_run_exit_trap_and_exit(G.last_exitcode);
         }
         /* mimic bash: exit 123abc == exit 255 + error msg */
         xfunc_error_retval = 255;
         /* bash: exit -2 == exit 254, no error msg */
-        hush_exit(xatoi(argv[0]) & 0xff);
+        save_history_run_exit_trap_and_exit(xatoi(argv[0]) & 0xff);
 }
 
 #if ENABLE_HUSH_TYPE