ash: simplify EOF/newline handling in list parser

Processing of here documents in ash has had a couple of breakages
which are now the subject of tests.  This commit should fix both.

It is based on the following commit in dash git by Herbert Xu:

   <7c245aa> [PARSER] Simplify EOF/newline handling in list parser

(See git://git.kernel.org/pub/scm/utils/dash/dash.git)

Reported-by: Natanael Copa <ncopa@alpinelinux.org>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 29 insertions, 34 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 72fc7d524..9a8bab5ab 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -10524,7 +10524,7 @@ static union node *andor(void);
 static union node *pipeline(void);
 static union node *parse_command(void);
 static void parseheredoc(void);
-static char peektoken(void);
+static int peektoken(void);
 static int readtoken(void);
 
 static union node *
@@ -10533,11 +10533,27 @@ list(int nlflag)
         union node *n1, *n2, *n3;
         int tok;
 
-        checkkwd = CHKNL | CHKKWD | CHKALIAS;
-        if (nlflag == 2 && peektoken())
-                return NULL;
         n1 = NULL;
         for (;;) {
+                switch (peektoken()) {
+                case TNL:
+                        if (!(nlflag & 1))
+                                break;
+                        parseheredoc();
+                        return n1;
+
+                case TEOF:
+                        if (!n1 && (nlflag & 1))
+                                n1 = NODE_EOF;
+                        parseheredoc();
+                        return n1;
+                }
+
+                checkkwd = CHKNL | CHKKWD | CHKALIAS;
+                if (nlflag == 2 && tokname_array[peektoken()][0])
+                        return n1;
+                nlflag |= 2;
+
                 n2 = andor();
                 tok = readtoken();
                 if (tok == TBACKGND) {
@@ -10563,30 +10579,15 @@ list(int nlflag)
                         n1 = n3;
                 }
                 switch (tok) {
+                case TNL:
+                case TEOF:
+                        tokpushback = 1;
+                        /* fall through */
                 case TBACKGND:
                 case TSEMI:
-                        tok = readtoken();
-                        /* fall through */
-                case TNL:
-                        if (tok == TNL) {
-                                parseheredoc();
-                                if (nlflag == 1)
-                                        return n1;
-                        } else {
-                                tokpushback = 1;
-                        }
-                        checkkwd = CHKNL | CHKKWD | CHKALIAS;
-                        if (peektoken())
-                                return n1;
                         break;
-                case TEOF:
-                        if (heredoclist)
-                                parseheredoc();
-                        else
-                                pungetc();              /* push back EOF on input */
-                        return n1;
                 default:
-                        if (nlflag == 1)
+                        if ((nlflag & 1))
                                 raise_error_unexpected_syntax(-1);
                         tokpushback = 1;
                         return n1;
@@ -11954,14 +11955,14 @@ readtoken(void)
         return t;
 }
 
-static char
+static int
 peektoken(void)
 {
         int t;
 
         t = readtoken();
         tokpushback = 1;
-        return tokname_array[t][0];
+        return t;
 }
 
 /*
@@ -11971,18 +11972,12 @@ peektoken(void)
 static union node *
 parsecmd(int interact)
 {
-        int t;
-
         tokpushback = 0;
+        checkkwd = 0;
+        heredoclist = 0;
         doprompt = interact;
         setprompt_if(doprompt, doprompt);
         needprompt = 0;
-        t = readtoken();
-        if (t == TEOF)
-                return NODE_EOF;
-        if (t == TNL)
-                return NULL;
-        tokpushback = 1;
         return list(1);
 }