ash: fix TMOUT not restoring tty attributes

function                                             old     new   delta
pgetc                                                420     500     +80
readtoken1                                          3202    3239     +37
read_line_input                                     3316    3337     +21
udhcpc_main                                         2610    2630     +20
file_get                                             266     272      +6
expandarg                                            958     963      +5
localcmd                                             257     259      +2
addLines                                              85      87      +2
read_line                                             94      95      +1
ed_main                                             2540    2541      +1
timed_out                                              1       -      -1
lineedit_read_key                                    256     255      -1
alrm_sighandler                                       44       -     -44
cmdloop                                              539     434    -105
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 10/2 up/down: 175/-151)          Total: 24 bytes
   text    data     bss     dec     hex filename
 887379     936   17200  905515   dd12b busybox_old
 887411     936   17192  905539   dd143 busybox_unstripped

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

2 files changed, 28 insertions, 47 deletions

diff --git a/shell/ash.c b/shell/ash.c
index bdc64790c..aaf21cd6f 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -102,8 +102,7 @@
 //config:       default n
 //config:       depends on ASH
 //config:       help
-//config:         Enables bash-like auto-logout after "$TMOUT" seconds
-//config:         of idle time.
+//config:         Enables bash-like auto-logout after $TMOUT seconds of idle time.
 //config:
 //config:config ASH_JOB_CONTROL
 //config:       bool "Job control"
@@ -408,6 +407,9 @@ static const char *var_end(const char *var)
 
 
 /* ============ Interrupts / exceptions */
+
+static void exitshell(void) NORETURN;
+
 /*
  * These macros allow the user to suspend the handling of interrupt signals
  * over a period of time.  This is similar to SIGHOLD or to sigblock, but
@@ -9573,10 +9575,21 @@ preadfd(void)
         if (!iflag || g_parsefile->pf_fd != STDIN_FILENO)
                 nr = nonblock_safe_read(g_parsefile->pf_fd, buf, IBUFSIZ - 1);
         else {
+                int timeout = -1;
+# if ENABLE_ASH_IDLE_TIMEOUT
+                if (iflag) {
+                        const char *tmout_var = lookupvar("TMOUT");
+                        if (tmout_var) {
+                                timeout = atoi(tmout_var) * 1000;
+                                if (timeout <= 0)
+                                        timeout = -1;
+                        }
+                }
+# endif
 # if ENABLE_FEATURE_TAB_COMPLETION
                 line_input_state->path_lookup = pathval();
 # endif
-                nr = read_line_input(cmdedit_prompt, buf, IBUFSIZ, line_input_state);
+                nr = read_line_input(line_input_state, cmdedit_prompt, buf, IBUFSIZ, timeout);
                 if (nr == 0) {
                         /* Ctrl+C pressed */
                         if (trap[SIGINT]) {
@@ -9587,9 +9600,17 @@ preadfd(void)
                         }
                         goto retry;
                 }
-                if (nr < 0 && errno == 0) {
-                        /* Ctrl+D pressed */
-                        nr = 0;
+                if (nr < 0) {
+                        if (errno == 0) {
+                                /* Ctrl+D pressed */
+                                nr = 0;
+                        }
+# if ENABLE_ASH_IDLE_TIMEOUT
+                        else if (errno == EAGAIN && timeout > 0) {
+                                printf("\007timed out waiting for input: auto-logout\n");
+                                exitshell();
+                        }
+# endif
                 }
         }
 #else
@@ -12056,23 +12077,6 @@ evalcmd(int argc UNUSED_PARAM, char **argv)
         return exitstatus;
 }
 
-#if ENABLE_ASH_IDLE_TIMEOUT
-static smallint timed_out;
-
-static void alrm_sighandler(int sig UNUSED_PARAM)
-{
-        /* Close stdin, making interactive command reading stop.
-         * Otherwise, timeout doesn't trigger until <Enter> is pressed.
-         */
-        int sv = errno;
-        close(0);
-        open("/dev/null", O_RDONLY);
-        errno = sv;
-
-        timed_out = 1;
-}
-#endif
-
 /*
  * Read and execute commands.
  * "Top" is nonzero for the top level command loop;
@@ -12089,20 +12093,6 @@ cmdloop(int top)
         TRACE(("cmdloop(%d) called\n", top));
         for (;;) {
                 int skip;
-#if ENABLE_ASH_IDLE_TIMEOUT
-                int tmout_seconds = 0;
-
-                if (top && iflag) {
-                        const char *tmout_var = lookupvar("TMOUT");
-                        if (tmout_var) {
-                                tmout_seconds = atoi(tmout_var);
-                                if (tmout_seconds > 0) {
-                                        signal(SIGALRM, alrm_sighandler);
-                                        alarm(tmout_seconds);
-                                }
-                        }
-                }
-#endif
 
                 setstackmark(&smark);
 #if JOBS
@@ -12115,14 +12105,6 @@ cmdloop(int top)
                         chkmail();
                 }
                 n = parsecmd(inter);
-#if ENABLE_ASH_IDLE_TIMEOUT
-                if (timed_out) {
-                        printf("\007timed out waiting for input: auto-logout\n");
-                        break;
-                }
-                if (tmout_seconds > 0)
-                        alarm(0);
-#endif
 #if DEBUG
                 if (DEBUG > 2 && debug && (n != NODE_EOF))
                         showtree(n);
@@ -12850,7 +12832,6 @@ ulimitcmd(int argc UNUSED_PARAM, char **argv)
 /*
  * Called to exit the shell.
  */
-static void exitshell(void) NORETURN;
 static void
 exitshell(void)
 {
diff --git a/shell/hush.c b/shell/hush.c
index e857e7464..00ef361cd 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1902,7 +1902,7 @@ static void get_user_input(struct in_str *i)
                 G.flag_SIGINT = 0;
                 /* buglet: SIGINT will not make new prompt to appear _at once_,
                  * only after <Enter>. (^C will work) */
-                r = read_line_input(prompt_str, G.user_input_buf, CONFIG_FEATURE_EDITING_MAX_LEN-1, G.line_input_state);
+                r = read_line_input(G.line_input_state, prompt_str, G.user_input_buf, CONFIG_FEATURE_EDITING_MAX_LEN-1, /*timeout*/ -1);
                 /* catch *SIGINT* etc (^C is handled by read_line_input) */
                 check_and_run_traps(0);
         } while (r == 0 || G.flag_SIGINT); /* repeat if ^C or SIGINT */