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.

5 files changed, 27 insertions, 19 deletions

diff --git a/client/mysql.cc b/client/mysql.cc
index 0d61ed4ec88..d103a3eec17 100644
--- a/client/mysql.cc
+++ b/client/mysql.cc
@@ -3728,7 +3728,8 @@ com_edit(String *buffer,char *line __attribute__((unused)))
       !(editor = (char *)getenv("VISUAL")))
     editor = "vi";
   strxmov(buff,editor," ",filename,NullS);
-  (void) system(buff);
+  if(system(buff) == -1)
+    goto err;
 
   MY_STAT stat_arg;
   if (!my_stat(filename,&stat_arg,MYF(MY_WME)))
diff --git a/client/mysql_upgrade.c b/client/mysql_upgrade.c
index ff414fff592..efa23610574 100644
--- a/client/mysql_upgrade.c
+++ b/client/mysql_upgrade.c
@@ -526,6 +526,7 @@ static int upgrade_already_done(void)
   FILE *in;
   char upgrade_info_file[FN_REFLEN]= {0};
   char buf[sizeof(MYSQL_SERVER_VERSION)+1];
+  char *res;
 
   if (get_upgrade_info_file_name(upgrade_info_file))
     return 0; /* Could not get filename => not sure */
@@ -538,7 +539,7 @@ static int upgrade_already_done(void)
     will be detected by the strncmp
   */
   bzero(buf, sizeof(buf));
-  fgets(buf, sizeof(buf), in);
+  res= fgets(buf, sizeof(buf), in);
 
   my_fclose(in, MYF(0));
 
diff --git a/client/mysqladmin.cc b/client/mysqladmin.cc
index 24b95be8626..699c2081b86 100644
--- a/client/mysqladmin.cc
+++ b/client/mysqladmin.cc
@@ -1050,14 +1050,16 @@ static void usage(void)
 static int drop_db(MYSQL *mysql, const char *db)
 {
   char name_buff[FN_REFLEN+20], buf[10];
+  char *input;
+
   if (!option_force)
   {
     puts("Dropping the database is potentially a very bad thing to do.");
     puts("Any data stored in the database will be destroyed.\n");
     printf("Do you really want to drop the '%s' database [y/N] ",db);
     fflush(stdout);
-    VOID(fgets(buf,sizeof(buf)-1,stdin));
-    if ((*buf != 'y') && (*buf != 'Y'))
+    input= fgets(buf, sizeof(buf)-1, stdin);
+    if (!input || ((*input != 'y') && (*input != 'Y')))
     {
       puts("\nOK, aborting database drop!");
       return -1;
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;
 }
 
diff --git a/client/mysqltest.c b/client/mysqltest.c
index 24d021b7239..79df511641d 100644
--- a/client/mysqltest.c
+++ b/client/mysqltest.c
@@ -426,10 +426,12 @@ DYNAMIC_STRING ds_res, ds_progress, ds_warning_messages;
 
 char builtin_echo[FN_REFLEN];
 
+static void cleanup_and_exit(int exit_code) __attribute__((noreturn));
+
 void die(const char *fmt, ...)
-  ATTRIBUTE_FORMAT(printf, 1, 2);
+  ATTRIBUTE_FORMAT(printf, 1, 2) __attribute__((noreturn));
 void abort_not_supported_test(const char *fmt, ...)
-  ATTRIBUTE_FORMAT(printf, 1, 2);
+  ATTRIBUTE_FORMAT(printf, 1, 2) __attribute__((noreturn));
 void verbose_msg(const char *fmt, ...)
   ATTRIBUTE_FORMAT(printf, 1, 2);
 void warning_msg(const char *fmt, ...)
@@ -3385,10 +3387,9 @@ void do_wait_for_slave_to_stop(struct st_command *c __attribute__((unused)))
   MYSQL* mysql = &cur_con->mysql;
   for (;;)
   {
-    MYSQL_RES *res;
+    MYSQL_RES *UNINIT_VAR(res);
     MYSQL_ROW row;
     int done;
-    LINT_INIT(res);
 
     if (mysql_query(mysql,"show status like 'Slave_running'") ||
 	!(res=mysql_store_result(mysql)))
@@ -4710,13 +4711,12 @@ my_bool end_of_query(int c)
 
 int read_line(char *buf, int size)
 {
-  char c, last_quote;
+  char c, UNINIT_VAR(last_quote);
   char *p= buf, *buf_end= buf + size - 1;
   int skip_char= 0;
   enum {R_NORMAL, R_Q, R_SLASH_IN_Q,
         R_COMMENT, R_LINE_START} state= R_LINE_START;
   DBUG_ENTER("read_line");
-  LINT_INIT(last_quote);
 
   start_lineno= cur_file->lineno;
   DBUG_PRINT("info", ("Starting to read at lineno: %d", start_lineno));
@@ -5978,8 +5978,7 @@ void run_query_normal(struct st_connection *cn, struct st_command *command,
 
     if (!disable_result_log)
     {
-      ulonglong affected_rows;    /* Ok to be undef if 'disable_info' is set */
-      LINT_INIT(affected_rows);
+      ulonglong UNINIT_VAR(affected_rows);    /* Ok to be undef if 'disable_info' is set */
 
       if (res)
       {