I fixed the bug too and had to merge conflicts

myisammrg/myrg_open.c:
  merged

client/mysqltest.c

@@ -113,7 +113,7 @@ struct query
   enum {Q_CONNECTION, Q_QUERY, Q_CONNECT,
 	Q_SLEEP, Q_INC, Q_DEC,Q_SOURCE,
 	Q_DISCONNECT,Q_LET, Q_ECHO, Q_WHILE, Q_END_BLOCK,
-	Q_UNKNOWN} type;
+	Q_SYSTEM, Q_UNKNOWN} type;
 };
 
 #define DS_CHUNK   16384
@@ -330,11 +330,21 @@ int do_source(struct query* q)
 int eval_expr(VAR* v, char* p, char* p_end)
 {
   VAR* vp;
-  if((vp = var_get(p,p_end,0)))
+  if(*p == '$')
     {
-      memcpy(v, vp, sizeof(VAR));
+      if((vp = var_get(p,p_end,0)))
+	{
+	  memcpy(v, vp, sizeof(VAR));
+	  return 0;
+	}
+    }
+  else
+    {
+      v->str_val = p;
+      v->str_val_len = p_end ? p_end - p : strlen(p);
       return 0;
     }
+  
   if(p_end)
     *p_end = 0;
   die("Invalid expr: %s", p);
@@ -365,6 +375,25 @@ int do_dec(struct query* q)
   return 0;
 }
 
+int do_system(struct query* q)
+{
+  char* p;
+  VAR v;
+  p = (char*)q->q + q->first_word_len;
+  while(*p && isspace(*p)) p++;
+  eval_expr(&v, p, 0); /* NULL terminated */
+  if(v.str_val_len > 1)
+    {
+      char expr_buf[512];
+      if((uint)v.str_val_len > sizeof(expr_buf) - 1)
+	v.str_val_len = sizeof(expr_buf) - 1;
+      memcpy(expr_buf, v.str_val, v.str_val_len);
+      expr_buf[v.str_val_len] = 0;
+      if(system(expr_buf) && q->abort_on_error)
+	die("system command '%s' failed", expr_buf);
+    }
+  return 0;
+}
 
 int do_echo(struct query* q)
 {
@@ -1006,7 +1035,6 @@ void reject_dump(const char* record_file, char* buf, int size)
 {
   char reject_file[MAX_RECORD_FILE+16];
   char* p;
-  FILE* freject;
   
   p = reject_file;
   p = safe_str_append(p, record_file, sizeof(reject_file));
@@ -1021,7 +1049,6 @@ int run_query(MYSQL* mysql, struct query* q)
   MYSQL_FIELD* fields;
   MYSQL_ROW row;
   int num_fields,i, error = 0;
-  struct stat info;
   unsigned long* lengths;
   char* val;
   int len;
@@ -1181,6 +1208,8 @@ void get_query_type(struct query* q)
     case 6:
       if(check_first_word(q, "source", 6))
 	q->type = Q_SOURCE;
+      else if(check_first_word(q, "system", 6))
+	q->type = Q_SYSTEM;
       break;
     case 7:
       if(check_first_word(q, "connect", 7))
@@ -1254,6 +1283,7 @@ int main(int argc, char** argv)
 	    case Q_INC: do_inc(q); break;
 	    case Q_DEC: do_dec(q); break;
 	    case Q_ECHO: do_echo(q); break;
+	    case Q_SYSTEM: do_system(q); break;
 	    case Q_LET: do_let(q); break;
 	    case Q_QUERY: error |= run_query(&cur_con->mysql, q); break;
 	    default: processed = 0; break;
@@ -1277,10 +1307,12 @@ int main(int argc, char** argv)
   close_cons();
 
   if(result_file)
-    if(!record && ds_res.len)
-      error |= check_result(&ds_res, result_file);
-    else
-      str_to_file(result_file, ds_res.str, ds_res.len);
+    {
+      if(!record && ds_res.len)
+	error |= check_result(&ds_res, result_file);
+      else
+	str_to_file(result_file, ds_res.str, ds_res.len);
+    }
   dyn_string_end(&ds_res);
   
   if (!silent) {

myisammrg/myrg_open.c

@@ -45,6 +45,7 @@ int handle_locking;
   DBUG_ENTER("myrg_open");
 
   LINT_INIT(last_isam);
+  LINT_INIT(m_info);
   isam=0;
   errpos=files=0;
   bzero((gptr) &info,sizeof(info));
@@ -84,7 +85,7 @@ int handle_locking;
 				       MYF(MY_WME))))
     goto err;
   *m_info=info;
-  m_info->open_tables=(MYRG_TABLE *) (m_info+1);
+  m_info->open_tables=(files) ? (MYRG_TABLE *) (m_info+1) : 0;
   m_info->tables=files;
   errpos=2;
 
@@ -110,11 +111,10 @@ int handle_locking;
     my_errno=HA_ERR_RECORD_FILE_FULL;
     goto err;
   }
-  if (files)
-    m_info->keys=m_info->open_tables->table->s->base.keys;
-
+  m_info->keys=(files) ? m_info->open_tables->table->s->base.keys : 0;
   bzero((char*) &m_info->by_key,sizeof(m_info->by_key));
 
+  /* this works ok if the table list is empty */
   m_info->end_table=m_info->open_tables+files;
   m_info->last_used_table=m_info->open_tables;
 

mysql-test/r/rpl000016.result

+s	
+Could not break slave	
+Tried hard	

mysql-test/t/rpl000016-slave-master-info.opt

+--server-id=2

mysql-test/t/rpl000016.test

+connect (master,localhost,root,,test,0,var/tmp/mysql.sock);
+connect (slave,localhost,root,,test,0,var/tmp/mysql-slave.sock);
+system cat /dev/null > var/slave-data/master.info;
+system chmod 000 var/slave-data/master.info;
+connection slave;
+!slave start;
+system chmod 600 var/slave-data/master.info;
+!slave start;
+!change master to master_host='127.0.0.1',master_port=9306,master_user='root'; 
+reset slave;
+!change master to master_host='127.0.0.1',master_port=9306,master_user='root'; 
+slave start;
+connection master;
+drop table if exists foo;
+create table foo(s text);
+insert into foo values('Could not break slave'),('Tried hard');
+connection slave;
+sleep 0.3;
+select * from foo;

sql/sql_repl.cc

@@ -34,7 +34,8 @@ static int send_file(THD *thd)
   char fname[FN_REFLEN+1];
   char *buf;
   const char *errmsg = 0;
-  int old_timeout,packet_len;
+  int old_timeout;
+  uint packet_len;
   DBUG_ENTER("send_file");
 
   // the client might be slow loading the data, give him wait_timeout to do
@@ -63,7 +64,6 @@ static int send_file(THD *thd)
   // this is needed to make replicate-ignore-db
   if (!strcmp(fname,"/dev/null"))
     goto end;
-  // TODO: work on the well-known system that does not have a /dev/null :-)
 
   if ((fd = my_open(fname, O_RDONLY, MYF(MY_WME))) < 0)
   {
@@ -553,9 +553,8 @@ int stop_slave(THD* thd, bool net_report )
     // do not abort the slave in the middle of a query, so we do not set
     // thd->killed for the slave thread
     thd->proc_info = "waiting for slave to die";
-    while(slave_running) // we may miss slave start broadcast, if it starts
-      // very quickly
-     pthread_cond_wait(&COND_slave_stopped, &LOCK_slave);
+    while(slave_running) 
+      pthread_cond_wait(&COND_slave_stopped, &LOCK_slave);
   }
   else
     err = "Slave is not running";
@@ -643,8 +642,11 @@ int change_master(THD* thd)
   thd->proc_info = "changing master";
   LEX_MASTER_INFO* lex_mi = &thd->lex.mi;
 
-  if(!glob_mi.inited)
-    init_master_info(&glob_mi);
+  if(init_master_info(&glob_mi))
+    {
+      send_error(&thd->net, 0, "Could not initialize master info");
+      return 1;
+    }
   
   pthread_mutex_lock(&glob_mi.lock);
   if((lex_mi->host || lex_mi->port) && !lex_mi->log_file_name && !lex_mi->pos)