Bug #43414 Parenthesis (and other) warnings compiling MySQL

with gcc 4.3.2
      
This patch fixes a number of GCC warnings about variables used
before initialized. A new macro UNINIT_VAR() is introduced for
use in the variable declaration, and LINT_INIT() usage will be
gradually deprecated. (A workaround is used for g++, pending a
patch for a g++ bug.)
      
GCC warnings for unused results (attribute warn_unused_result)
for a number of system calls (present at least in later
Ubuntus, where the usual void cast trick doesn't work) are
also fixed.


client/mysqlmanager-pwgen.c:
  A fix for warn_unused_result, adding fallback to use of
  srand()/rand() if /dev/random cannot be used. Also actually
  adds calls to rand() in the second branch so that it actually
  creates a random password.

1 files changed, 12 insertions, 7 deletions

diff --git a/client/mysqlmanager-pwgen.c b/client/mysqlmanager-pwgen.c
index 568358b1cda..1be4d8b6970 100644
--- a/client/mysqlmanager-pwgen.c
+++ b/client/mysqlmanager-pwgen.c
@@ -104,29 +104,34 @@ void get_pass(char* pw, int len)
 {
   FILE* fp;
   char* pw_end=pw+len;
+  size_t elements_read= 0;
   /*
     /dev/random is more secure than  rand() because the seed is easy to
     predict, so we resort to rand() only if /dev/random is not available
   */
   if ((fp=fopen("/dev/random","r")))
   {
-    fread(pw,len,1,fp);
-    fclose(fp);
-    while (pw<pw_end)
+    if ((elements_read= fread(pw,len,1,fp)))
     {
-      char tmp= 'a'+((uint)*pw % 26);
-      *pw++= tmp;
+      while (pw<pw_end)
+      {
+        char tmp= 'a'+((uint)*pw % 26);
+        *pw++= tmp;
+      }
     }
+    fclose(fp);
   }
-  else
+
+  if (elements_read != 1)
   {
     srand(time(NULL));
     while (pw<pw_end)
     {
-      char tmp= 'a'+((uint)*pw % 26);
+      char tmp= 'a'+((uint)rand() % 26);
       *pw++= tmp;
     }
   }
+
   *pw_end=0;
 }