[PATCH] xalloc: delay setting size until success

[Paul Eggert]

* lib/xalloc.h (x2nrealloc): Don’t change *PN until after xrealloc
succeeds, in case xalloc_die or one of its callees or longjmp
targets uses *PN.  Similar code in xpalloc already does this.
---
 ChangeLog    | 7 +++++++
 lib/xalloc.h | 3 ++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 78bf3a5a7..784409dba 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2021-03-31  Paul Eggert  <eggert@cs.ucla.edu>
+
+       xalloc: delay setting size until success
+       * lib/xalloc.h (x2nrealloc): Don’t change *PN until after xrealloc
+       succeeds, in case xalloc_die or one of its callees or longjmp
+       targets uses *PN.  Similar code in xpalloc already does this.
+
 2021-03-28  Paul Eggert  <eggert@cs.ucla.edu>
 
        xalloc: new function xpalloc, from dfa
diff --git a/lib/xalloc.h b/lib/xalloc.h
index 76d83c63c..5633fdf3c 100644
--- a/lib/xalloc.h
+++ b/lib/xalloc.h
@@ -206,8 +206,9 @@ x2nrealloc (void *p, size_t *pn, size_t s)
       n += n / 2 + 1;
     }
 
+  p = xrealloc (p, n * s);
   *pn = n;
-  return xrealloc (p, n * s);
+  return p;
 }
 
 /* Return a pointer to a new buffer of N bytes.  This is like xmalloc,
-- 
2.30.2