ash: parser: Save/restore here-documents in command substitution

Upstream comment:

    Date: Sat, 19 May 2018 02:39:42 +0800
    parser: Save/restore here-documents in command substitution

    This patch changes the parsing of here-documents within command
    substitution, both old style and new style.  In particular, the
    original here-document list is saved upon the beginning of parsing
    command substitution and restored when exiting.

    This means that here-documents outside of command substitution
    can no longer be filled by text within it and vice-versa.

    Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

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

1 files changed, 16 insertions, 9 deletions

diff --git a/shell/ash.c b/shell/ash.c
index fbe8dd9e4..e0ddf7198 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -12733,6 +12733,7 @@ parsebackq: {
         union node *n;
         char *str;
         size_t savelen;
+        struct heredoc *saveheredoclist;
         smallint saveprompt = 0;
 
         str = NULL;
@@ -12808,6 +12809,9 @@ parsebackq: {
         *nlpp = stzalloc(sizeof(**nlpp));
         /* (*nlpp)->next = NULL; - stzalloc did it */
 
+        saveheredoclist = heredoclist;
+        heredoclist = NULL;
+
         if (oldstyle) {
                 saveprompt = doprompt;
                 doprompt = 0;
@@ -12817,18 +12821,21 @@ parsebackq: {
 
         if (oldstyle)
                 doprompt = saveprompt;
-        else if (readtoken() != TRP)
-                raise_error_unexpected_syntax(TRP);
+        else {
+                if (readtoken() != TRP)
+                        raise_error_unexpected_syntax(TRP);
+                setinputstring(nullstr);
+                parseheredoc();
+        }
+
+        heredoclist = saveheredoclist;
 
         (*nlpp)->n = n;
-        if (oldstyle) {
-                /*
-                 * Start reading from old file again, ignoring any pushed back
-                 * tokens left from the backquote parsing
-                 */
-                popfile();
+        /* Start reading from old file again. */
+        popfile();
+        /* Ignore any pushed back tokens left from the backquote parsing. */
+        if (oldstyle)
                 tokpushback = 0;
-        }
         while (stackblocksize() <= savelen)
                 growstackblock();
         STARTSTACKSTR(out);