3 files changed, 52 insertions, 70 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 02b21510e..2bfec83e6 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -9991,6 +9991,7 @@ static smallint checkkwd;
 #define CHKALIAS        0x1
 #define CHKKWD          0x2
 #define CHKNL           0x4
+#define CHKEOFMARK      0x8
 
 /*
  * Push a string back onto the input at this current parsefile level.
@@ -10303,31 +10304,6 @@ pgetc_without_PEOA(void)
 #endif
 
 /*
- * Read a line from the script.
- */
-static char *
-pfgets(char *line, int len)
-{
-        char *p = line;
-        int nleft = len;
-        int c;
-
-        while (--nleft > 0) {
-                c = pgetc_without_PEOA();
-                if (c == PEOF) {
-                        if (p == line)
-                                return NULL;
-                        break;
-                }
-                *p++ = c;
-                if (c == '\n')
-                        break;
-        }
-        *p = '\0';
-        return line;
-}
-
-/*
  * Undo a call to pgetc.  Only two characters may be pushed back.
  * PEOF may be pushed back.
  */
@@ -10960,8 +10936,6 @@ raise_error_unexpected_syntax(int token)
         /* NOTREACHED */
 }
 
-#define EOFMARKLEN 79
-
 /* parsing is heavily cross-recursive, need these forward decls */
 static union node *andor(void);
 static union node *pipeline(void);
@@ -11141,43 +11115,22 @@ fixredir(union node *n, const char *text, int err)
         }
 }
 
-/*
- * Returns true if the text contains nothing to expand (no dollar signs
- * or backquotes).
- */
-static int
-noexpand(const char *text)
-{
-        unsigned char c;
-
-        while ((c = *text++) != '\0') {
-                if (c == CTLQUOTEMARK)
-                        continue;
-                if (c == CTLESC)
-                        text++;
-                else if (SIT(c, BASESYNTAX) == CCTL)
-                        return 0;
-        }
-        return 1;
-}
-
 static void
 parsefname(void)
 {
         union node *n = redirnode;
 
+        if (n->type == NHERE)
+                checkkwd = CHKEOFMARK;
         if (readtoken() != TWORD)
                 raise_error_unexpected_syntax(-1);
         if (n->type == NHERE) {
                 struct heredoc *here = heredoc;
                 struct heredoc *p;
-                int i;
 
                 if (quoteflag == 0)
                         n->type = NXHERE;
                 TRACE(("Here document %d\n", n->type));
-                if (!noexpand(wordtext) || (i = strlen(wordtext)) == 0 || i > EOFMARKLEN)
-                        raise_error_syntax("illegal eof marker for << redirection");
                 rmescapes(wordtext, 0);
                 here->eofmark = wordtext;
                 here->next = NULL;
@@ -11593,7 +11546,6 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
         /* c parameter is an unsigned char or PEOF or PEOA */
         char *out;
         size_t len;
-        char line[EOFMARKLEN + 1];
         struct nodelist *bqlist;
         smallint quotef;
         smallint dblquote;
@@ -11816,6 +11768,9 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
  */
 checkend: {
         if (eofmark) {
+                int markloc;
+                char *p;
+
 #if ENABLE_ASH_ALIAS
                 if (c == PEOA)
                         c = pgetc_without_PEOA();
@@ -11825,27 +11780,42 @@ checkend: {
                                 c = pgetc_without_PEOA();
                         }
                 }
-                if (c == *eofmark) {
-                        if (pfgets(line, sizeof(line)) != NULL) {
-                                char *p, *q;
-                                int cc;
-
-                                p = line;
-                                for (q = eofmark + 1;; p++, q++) {
-                                        cc = *p;
-                                        if (cc == '\n')
-                                                cc = 0;
-                                        if (!*q || cc != *q)
-                                                break;
-                                }
-                                if (cc == *q) {
-                                        c = PEOF;
-                                        nlnoprompt();
-                                } else {
-                                        pushstring(line, NULL);
+
+                markloc = out - (char *)stackblock();
+                for (p = eofmark; STPUTC(c, out), *p; p++) {
+                        if (c != *p)
+                                goto more_heredoc;
+
+                        c = pgetc_without_PEOA();
+                }
+
+                if (c == '\n' || c == PEOF) {
+                        c = PEOF;
+                        g_parsefile->linno++;
+                        needprompt = doprompt;
+                } else {
+                        int len_here;
+
+ more_heredoc:
+                        p = (char *)stackblock() + markloc + 1;
+                        len_here = out - p;
+
+                        if (len_here) {
+                                len_here -= (c >= PEOF);
+                                c = p[-1];
+
+                                if (len_here) {
+                                        char *str;
+
+                                        str = alloca(len_here + 1);
+                                        *(char *)mempcpy(str, p, len_here) = '\0';
+
+                                        pushstring(str, NULL);
                                 }
                         }
                 }
+
+                STADJUST((char *)stackblock() + markloc - out, out);
         }
         goto checkend_return;
 }
@@ -11939,7 +11909,8 @@ parsesub: {
         int typeloc;
 
         c = pgetc_eatbnl();
-        if (c > 255 /* PEOA or PEOF */
+        if ((checkkwd & CHKEOFMARK)
+         || c > 255 /* PEOA or PEOF */
          || (c != '(' && c != '{' && !is_name(c) && !is_special(c))
         ) {
 #if BASH_DOLLAR_SQUOTE
diff --git a/shell/ash_test/ash-heredoc/heredoc_empty.right b/shell/ash_test/ash-heredoc/heredoc_empty.right
new file mode 100644
index 000000000..0eabe3671
--- /dev/null
+++ b/shell/ash_test/ash-heredoc/heredoc_empty.right
@@ -0,0 +1,3 @@
+OK
+OK
+OK
diff --git a/shell/ash_test/ash-heredoc/heredoc_empty.tests b/shell/ash_test/ash-heredoc/heredoc_empty.tests
new file mode 100755
index 000000000..3629bc6d1
--- /dev/null
+++ b/shell/ash_test/ash-heredoc/heredoc_empty.tests
@@ -0,0 +1,8 @@
+unset a
+cat <<- $a
+        OK
+$a
+cat <<- ""
+        OK
+
+echo OK