ash: allocate line editing structure only if needed

function                                             old     new   delta
optschanged                                           91     128     +37
historycmd                                            13      17      +4
setcmd                                                80      78      -2
ash_main                                            1167    1150     -17
options                                              576     552     -24
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/3 up/down: 41/-43)             Total: -2 bytes

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

1 files changed, 70 insertions, 37 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 924e17f32..c8857366c 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -315,9 +315,16 @@ static const char *const optletters_optnames[] = {
         "e"   "errexit",
         "f"   "noglob",
         "I"   "ignoreeof",
+/* The below allows this invocation:
+ * ash -c 'set -i; echo $-; sleep 5; echo $-'
+ * to be ^C-ed and get to interactive ash prompt.
+ * bash does not support this "set -i". bash also has no
+ * "set -o interactive".
+ */
         "i"   "interactive",
         "m"   "monitor",
         "n"   "noexec",
+/* Ditto: bash has no "set -s" and "set -o stdin" */
         "s"   "stdin",
         "x"   "xtrace",
         "v"   "verbose",
@@ -334,10 +341,25 @@ static const char *const optletters_optnames[] = {
         ,"\0"  "debug"
 #endif
 };
+//bash 4.4.23 also has these opts (with these defaults):
+//braceexpand           on
+//emacs                 on
+//errtrace              off
+//functrace             off
+//hashall               on
+//histexpand            off
+//history               on
+//interactive-comments  on
+//keyword               off
+//onecmd                off
+//physical              off
+//posix                 off
+//privileged            off
 
 #define optletters(n)  optletters_optnames[n][0]
 #define optnames(n)   (optletters_optnames[n] + 1)
 
+
 enum { NOPTS = ARRAY_SIZE(optletters_optnames) };
 
 
@@ -9514,8 +9536,8 @@ setinteractive(int on)
         setsignal(SIGINT);
         setsignal(SIGQUIT);
         setsignal(SIGTERM);
-#if !ENABLE_FEATURE_SH_EXTRA_QUIET
         if (is_interactive > 1) {
+#if !ENABLE_FEATURE_SH_EXTRA_QUIET
                 /* Looks like they want an interactive shell */
                 static smallint did_banner;
 
@@ -9529,8 +9551,12 @@ setinteractive(int on)
                         );
                         did_banner = 1;
                 }
-        }
 #endif
+#if ENABLE_FEATURE_EDITING
+                if (!line_input_state)
+                        line_input_state = new_line_input_t(FOR_SHELL | WITH_PATH_LOOKUP);
+#endif
+        }
 }
 
 static void
@@ -9542,10 +9568,12 @@ optschanged(void)
         setinteractive(iflag);
         setjobctl(mflag);
 #if ENABLE_FEATURE_EDITING_VI
-        if (viflag)
-                line_input_state->flags |= VI_MODE;
-        else
-                line_input_state->flags &= ~VI_MODE;
+        if (line_input_state) {
+                if (viflag)
+                        line_input_state->flags |= VI_MODE;
+                else
+                        line_input_state->flags &= ~VI_MODE;
+        }
 #else
         viflag = 0; /* forcibly keep the option off */
 #endif
@@ -10519,13 +10547,11 @@ preadfd(void)
         else {
 # if ENABLE_ASH_IDLE_TIMEOUT
                 int timeout = -1;
-                if (iflag) {
-                        const char *tmout_var = lookupvar("TMOUT");
-                        if (tmout_var) {
-                                timeout = atoi(tmout_var) * 1000;
-                                if (timeout <= 0)
-                                        timeout = -1;
-                        }
+                const char *tmout_var = lookupvar("TMOUT");
+                if (tmout_var) {
+                        timeout = atoi(tmout_var) * 1000;
+                        if (timeout <= 0)
+                                timeout = -1;
                 }
                 line_input_state->timeout = timeout;
 # endif
@@ -11086,14 +11112,17 @@ setoption(int flag, int val)
         ash_msg_and_raise_error("illegal option %c%c", val ? '-' : '+', flag);
         /* NOTREACHED */
 }
+/* If login_sh is not NULL, we are called to parse command line opts,
+ * not "set -opts"
+ */
 static int
-options(int cmdline, int *login_sh)
+options(int *login_sh)
 {
         char *p;
         int val;
         int c;
 
-        if (cmdline)
+        if (login_sh)
                 minusc = NULL;
         while ((p = *argptr) != NULL) {
                 c = *p++;
@@ -11104,7 +11133,7 @@ options(int cmdline, int *login_sh)
                 if (c == '-') {
                         val = 1;
                         if (p[0] == '\0' || LONE_DASH(p)) {
-                                if (!cmdline) {
+                                if (!login_sh) {
                                         /* "-" means turn off -x and -v */
                                         if (p[0] == '\0')
                                                 xflag = vflag = 0;
@@ -11117,26 +11146,31 @@ options(int cmdline, int *login_sh)
                 }
                 /* first char was + or - */
                 while ((c = *p++) != '\0') {
-                        /* bash 3.2 indeed handles -c CMD and +c CMD the same */
-                        if (c == 'c' && cmdline) {
-                                minusc = p;     /* command is after shell args */
-                        } else if (c == 'o') {
+                        if (login_sh) {
+                                /* bash 3.2 indeed handles -c CMD and +c CMD the same */
+                                if (c == 'c') {
+                                        minusc = p; /* command is after shell args */
+                                        continue;
+                                }
+                                if (c == 'l') {
+                                        *login_sh = 1; /* -l or +l == --login */
+                                        continue;
+                                }
+                                /* bash does not accept +-login, we also won't */
+                                if (val && (c == '-')) { /* long options */
+                                        if (strcmp(p, "login") == 0) {
+                                                *login_sh = 1;
+                                        }
+                                        break;
+                                }
+                        }
+                        if (c == 'o') {
                                 if (plus_minus_o(*argptr, val)) {
                                         /* it already printed err message */
                                         return 1; /* error */
                                 }
                                 if (*argptr)
                                         argptr++;
-                        } else if (cmdline && (c == 'l')) { /* -l or +l == --login */
-                                if (login_sh)
-                                        *login_sh = 1;
-                        /* bash does not accept +-login, we also won't */
-                        } else if (cmdline && val && (c == '-')) { /* long options */
-                                if (strcmp(p, "login") == 0) {
-                                        if (login_sh)
-                                                *login_sh = 1;
-                                }
-                                break;
                         } else {
                                 setoption(c, val);
                         }
@@ -11227,7 +11261,7 @@ setcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
                 return showvars(nullstr, 0, VUNSET);
 
         INT_OFF;
-        retval = options(/*cmdline:*/ 0, NULL);
+        retval = options(/*login_sh:*/ NULL);
         if (retval == 0) { /* if no parse error... */
                 optschanged();
                 if (*argptr != NULL) {
@@ -13685,7 +13719,8 @@ helpcmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 static int FAST_FUNC
 historycmd(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
 {
-        show_history(line_input_state);
+        if (line_input_state)
+                show_history(line_input_state);
         return EXIT_SUCCESS;
 }
 #endif
@@ -14001,7 +14036,8 @@ exitshell(void)
         int status;
 
 #if ENABLE_FEATURE_EDITING_SAVE_ON_EXIT
-        save_history(line_input_state);
+        if (line_input_state)
+                save_history(line_input_state);
 #endif
         status = exitstatus;
         TRACE(("pid %d, exitshell(%d)\n", getpid(), status));
@@ -14123,7 +14159,7 @@ procargs(char **argv)
         argptr = xargv;
         for (i = 0; i < NOPTS; i++)
                 optlist[i] = 2;
-        if (options(/*cmdline:*/ 1, &login_sh)) {
+        if (options(&login_sh)) {
                 /* it already printed err message */
                 raise_exception(EXERROR);
         }
@@ -14249,9 +14285,6 @@ int ash_main(int argc UNUSED_PARAM, char **argv)
         monitor(4, etext, profile_buf, sizeof(profile_buf), 50);
 #endif
 
-#if ENABLE_FEATURE_EDITING
-        line_input_state = new_line_input_t(FOR_SHELL | WITH_PATH_LOOKUP);
-#endif
         state = 0;
         if (setjmp(jmploc.loc)) {
                 smallint e;