hush: don't save history in subshells; on NOMMU, don't be interactive on reexec

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 72 insertions, 54 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 5707b4b31..5f4c0cca5 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -930,6 +930,12 @@ 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;
@@ -2105,7 +2111,9 @@ static const char* FAST_FUNC get_local_var_value(const char *name);
 static 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:
@@ -10218,6 +10226,53 @@ static int run_and_free_list(struct pipe *pi)
 /*
  * Initialization and main
  */
+#if 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;
@@ -10356,7 +10411,6 @@ 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),
         };
@@ -10384,9 +10438,6 @@ 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
@@ -10399,9 +10450,8 @@ 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");
@@ -10568,6 +10618,7 @@ 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);
@@ -10647,7 +10698,9 @@ 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;
 
@@ -10767,7 +10820,9 @@ int hush_main(int argc, char **argv)
          * Refer to Posix.2, the description of the 'sh' utility.
          */
 #if ENABLE_HUSH_JOB
-        if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+        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)
@@ -10813,57 +10868,18 @@ int hush_main(int argc, char **argv)
                          * (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);
+                        tcsetpgrp(G_interactive_fd, G.root_pid);
                 }
                 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);
-                                }
-                        } 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
+                init_line_editing();
         } else {
                 install_special_sighandlers();
         }
 #elif ENABLE_HUSH_INTERACTIVE
         /* No job control compiled in, only prompt/line editing */
-        if (isatty(STDIN_FILENO) && isatty(STDOUT_FILENO)) {
+        if (!G_reexeced_on_NOMMU
+         && 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 */
@@ -10872,6 +10888,8 @@ int hush_main(int argc, char **argv)
                                 /* give up */
                                 G_interactive_fd = 0;
                 }
+                if (G_interactive_fd)
+                        init_line_editing();
         }
         install_special_sighandlers();
 #else