Update XZ Utils to 5.0.5

src/xz/util.c

 ///////////////////////////////////////////////////////////////////////////////
 //
 /// \file       util.c
 /// \brief      Miscellaneous utility functions
 //
 //  Author:     Lasse Collin
 //
 //  This file has been put into the public domain.
 //  You can do whatever you want with this file.
 //
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "private.h"
 #include <stdarg.h>
 
 
 /// Buffers for uint64_to_str() and uint64_to_nicestr()
 static char bufs[4][128];
 
 /// Thousand separator support in uint64_to_str() and uint64_to_nicestr()
 static enum { UNKNOWN, WORKS, BROKEN } thousand = UNKNOWN;
 
 
 extern void *
 xrealloc(void *ptr, size_t size)
 {
         assert(size > 0);
 
+        // Save ptr so that we can free it if realloc fails.
+        // The point is that message_fatal ends up calling stdio functions
+        // which in some libc implementations might allocate memory from
+        // the heap. Freeing ptr improves the chances that there's free
+        // memory for stdio functions if they need it.
+        void *p = ptr;
         ptr = realloc(ptr, size);
-        if (ptr == NULL)
-                message_fatal("%s", strerror(errno));
+
+        if (ptr == NULL) {
+                const int saved_errno = errno;
+                free(p);
+                message_fatal("%s", strerror(saved_errno));
+        }
 
         return ptr;
 }
 
 
 extern char *
 xstrdup(const char *src)
 {
         assert(src != NULL);
         const size_t size = strlen(src) + 1;
@@ skipping 227 matching lines @@
 is_tty_stdout(void)
 {
         const bool ret = isatty(STDOUT_FILENO);
 
         if (ret)
                 message_error(_("Compressed data cannot be written to "
                                 "a terminal"));
 
         return ret;
 }