ash: in dotrap(), do not clear gotsig[] for SIGINT if there is no handler

 for it, otherwise raise interrupt gets confused later.
 The rest are readability fixes.

function                                             old     new   delta                                                                                                       
evaltreenr                                           817     818      +1                                                                                                       
evaltree                                             817     818      +1                                                                                                       
evalstring                                            88      89      +1                                                                                                       
cmdloop                                              420     419      -1                                                                                                       
evalskip                                               4       1      -3                                                                                                       
breakcmd                                              84      81      -3                                                                                                       
ash_main                                            1382    1379      -3                                                                                                       
evalloop                                             183     177      -6                                                                                                       
evalfor                                              231     225      -6                                                                                                       
------------------------------------------------------------------------------                                                                                                 
(add/remove: 0/0 grow/shrink: 3/6 up/down: 3/-22)             Total: -19 bytes

1 files changed, 69 insertions, 57 deletions

diff --git a/shell/ash.c b/shell/ash.c
index f93d73735..9bb1d421e 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -162,6 +162,9 @@ struct globals_misc {
 //      /* do we generate EXSIG events */
 //      int exsig; /* counter */
         volatile int suppressint; /* counter */
+// TODO: rename
+// pendingsig -> pending_sig
+// intpending -> pending_int
         volatile /*sig_atomic_t*/ smallint intpending; /* 1 = got SIGINT */
         /* last pending signal */
         volatile /*sig_atomic_t*/ smallint pendingsig;
@@ -210,7 +213,7 @@ struct globals_misc {
 #define S_HARD_IGN 4            /* signal is ignored permenantly */
 
         /* indicates specified signal received */
-        char gotsig[NSIG - 1]; /* offset by 1: "signal" 0 is meaningless */
+        uint8_t gotsig[NSIG - 1]; /* offset by 1: "signal" 0 is meaningless */
         char *trap[NSIG];
 
         /* Rarely referenced stuff */
@@ -279,7 +282,7 @@ static int isdigit_str9(const char *str)
 /*
  * Called to raise an exception.  Since C doesn't include exceptions, we
  * just do a longjmp to the exception handler.  The type of exception is
- * stored in the global variable "exception".
+ * stored in the global variable "exception_type".
  */
 static void raise_exception(int) NORETURN;
 static void
@@ -305,7 +308,7 @@ static void raise_interrupt(void) NORETURN;
 static void
 raise_interrupt(void)
 {
-        int i;
+        int ex_type;
 
         intpending = 0;
         /* Signal is not automatically unmasked after it is raised,
@@ -313,16 +316,16 @@ raise_interrupt(void)
         sigprocmask_allsigs(SIG_UNBLOCK);
         /* pendingsig = 0; - now done in onsig() */
 
-        i = EXSIG;
+        ex_type = EXSIG;
         if (gotsig[SIGINT - 1] && !trap[SIGINT]) {
                 if (!(rootshell && iflag)) {
                         /* Kill ourself with SIGINT */
                         signal(SIGINT, SIG_DFL);
                         raise(SIGINT);
                 }
-                i = EXINT;
+                ex_type = EXINT;
         }
-        raise_exception(i);
+        raise_exception(ex_type);
         /* NOTREACHED */
 }
 
@@ -366,37 +369,6 @@ force_int_on(void)
                 raise_interrupt(); \
 } while (0)
 
-/*
- * Ignore a signal. Avoids unnecessary system calls.
- */
-static void
-ignoresig(int signo)
-{
-        if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
-                signal(signo, SIG_IGN);
-        }
-        sigmode[signo - 1] = S_HARD_IGN;
-}
-
-/*
- * Signal handler. Only one usage site - in setsignal()
- */
-static void
-onsig(int signo)
-{
-        gotsig[signo - 1] = 1;
-
-        if (/* exsig || */ (signo == SIGINT && !trap[SIGINT])) {
-                if (!suppressint) {
-                        pendingsig = 0;
-                        raise_interrupt(); /* does not return */
-                }
-                intpending = 1;
-        } else {
-                pendingsig = signo;
-        }
-}
-
 
 /* ============ Stdout/stderr output */
 
@@ -3288,6 +3260,39 @@ static void setjobctl(int);
 #endif
 
 /*
+ * Ignore a signal.
+ */
+static void
+ignoresig(int signo)
+{
+        /* Avoid unnecessary system calls. Is it already SIG_IGNed? */
+        if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) {
+                /* No, need to do it */
+                signal(signo, SIG_IGN);
+        }
+        sigmode[signo - 1] = S_HARD_IGN;
+}
+
+/*
+ * Signal handler. Only one usage site - in setsignal()
+ */
+static void
+onsig(int signo)
+{
+        gotsig[signo - 1] = 1;
+
+        if (/* exsig || */ (signo == SIGINT && !trap[SIGINT])) {
+                if (!suppressint) {
+                        pendingsig = 0;
+                        raise_interrupt(); /* does not return */
+                }
+                intpending = 1;
+        } else {
+                pendingsig = signo;
+        }
+}
+
+/*
  * Set the signal handler for the specified signal.  The routine figures
  * out what it should be set to.
  */
@@ -7914,49 +7919,56 @@ defun(char *name, union node *func)
         INT_ON;
 }
 
-static int evalskip;            /* set if we are skipping commands */
-/* reasons for skipping commands (see comment on breakcmd routine) */
+/* Reasons for skipping commands (see comment on breakcmd routine) */
 #define SKIPBREAK      (1 << 0)
 #define SKIPCONT       (1 << 1)
 #define SKIPFUNC       (1 << 2)
 #define SKIPFILE       (1 << 3)
 #define SKIPEVAL       (1 << 4)
+static smallint evalskip;       /* set to SKIPxxx if we are skipping commands */
 static int skipcount;           /* number of levels to skip */
 static int funcnest;            /* depth of function calls */
 static int loopnest;            /* current loop nesting level */
 
-/* forward decl way out to parsing code - dotrap needs it */
+/* Forward decl way out to parsing code - dotrap needs it */
 static int evalstring(char *s, int mask);
 
-/*
- * Called to execute a trap.  Perhaps we should avoid entering new trap
- * handlers while we are executing a trap handler.
+/* Called to execute a trap.
+ * Single callsite - at the end of evaltree().
+ * If we return non-zero, exaltree raises EXEXIT exception.
+ *
+ * Perhaps we should avoid entering new trap handlers
+ * while we are executing a trap handler. [is it a TODO?]
  */
 static int
 dotrap(void)
 {
-        char *p;
-        char *q;
-        int i;
-        int savestatus;
-        int skip;
+        uint8_t *g;
+        int sig;
+        uint8_t savestatus;
 
         savestatus = exitstatus;
         pendingsig = 0;
         xbarrier();
 
-        for (i = 1, q = gotsig; i < NSIG; i++, q++) {
-                if (!*q)
-                        continue;
-                *q = '\0';
+        for (sig = 1, g = gotsig; sig < NSIG; sig++, g++) {
+                int want_exexit;
+                char *t;
 
-                p = trap[i];
-                if (!p)
+                if (*g == 0)
+                        continue;
+                t = trap[sig];
+                /* non-trapped SIGINT is handled separately by raise_interrupt,
+                 * don't upset it by resetting gotsig[SIGINT-1] */
+                if (sig == SIGINT && !t)
                         continue;
-                skip = evalstring(p, SKIPEVAL);
+                *g = 0;
+                if (!t)
+                        continue;
+                want_exexit = evalstring(t, SKIPEVAL);
                 exitstatus = savestatus;
-                if (skip)
-                        return skip;
+                if (want_exexit)
+                        return want_exexit;
         }
 
         return 0;