ash: memalloc: Add growstackto helper

Upstream commit:

    Date: Sat, 19 May 2018 02:39:46 +0800
    memalloc: Add growstackto helper

    This patch adds the growstackto helper which repeatedly calls
    growstackblock until the requested size is reached.

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

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

1 files changed, 12 insertions, 17 deletions

diff --git a/shell/ash.c b/shell/ash.c
index e0ddf7198..6505f4984 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -1740,6 +1740,15 @@ growstackstr(void)
         return (char *)stackblock() + len;
 }
 
+static char *
+growstackto(size_t len)
+{
+        while (stackblocksize() < len)
+                growstackblock();
+
+        return stackblock();
+}
+
 /*
  * Called from CHECKSTRSPACE.
  */
@@ -1747,18 +1756,8 @@ static char *
 makestrspace(size_t newlen, char *p)
 {
         size_t len = p - g_stacknxt;
-        size_t size;
-
-        for (;;) {
-                size_t nleft;
 
-                size = stackblocksize();
-                nleft = size - len;
-                if (nleft >= newlen)
-                        break;
-                growstackblock();
-        }
-        return (char *)stackblock() + len;
+        return growstackto(len + newlen) + len;
 }
 
 static char *
@@ -2584,9 +2583,7 @@ path_advance(const char **path, const char *name)
         for (p = start; *p && *p != ':' && *p != '%'; p++)
                 continue;
         len = p - start + strlen(name) + 2;     /* "2" is for '/' and '\0' */
-        while (stackblocksize() < len)
-                growstackblock();
-        q = stackblock();
+        q = growstackto(len);
         if (p != start) {
                 q = mempcpy(q, start, p - start);
                 *q++ = '/';
@@ -12836,9 +12833,7 @@ parsebackq: {
         /* Ignore any pushed back tokens left from the backquote parsing. */
         if (oldstyle)
                 tokpushback = 0;
-        while (stackblocksize() <= savelen)
-                growstackblock();
-        STARTSTACKSTR(out);
+        out = growstackto(savelen + 1);
         if (str) {
                 memcpy(out, str, savelen);
                 STADJUST(savelen, out);