BUG#12982 - LOAD DATA fails without any error for big files with big

            read buffer
Setting read buffer to values greater than SSIZE_MAX results in
unexpected behavior.

According to read(2) manual:
If count is greater than SSIZE_MAX, the result is unspecified.

Set upper limit for read_buffer_size and read_rnd_buffer_size to
SSIZE_MAX.


include/my_global.h:
  Define SSIZE_MAX if not defined.
sql/mysqld.cc:
  Set upper limit for read_buffer_size and read_rnd_buffer_size to
  SSIZE_MAX.

include/my_global.h

@@ -736,6 +736,9 @@ typedef SOCKET_SIZE_TYPE size_socket;
 #define DBL_MAX		1.79769313486231470e+308
 #define FLT_MAX		((float)3.40282346638528860e+38)
 #endif
+#ifndef SSIZE_MAX
+#define SSIZE_MAX (ssize_t)((~((size_t) 0)) / 2)
+#endif
 
 #if !defined(HAVE_ISINF) && !defined(isinf)
 #define isinf(X)    0

sql/mysqld.cc

@@ -5847,7 +5847,8 @@ The minimum value for this variable is 4096.",
    "Each thread that does a sequential scan allocates a buffer of this size for each table it scans. If you do many sequential scans, you may want to increase this value.",
    (gptr*) &global_system_variables.read_buff_size,
    (gptr*) &max_system_variables.read_buff_size,0, GET_ULONG, REQUIRED_ARG,
-   128*1024L, IO_SIZE*2+MALLOC_OVERHEAD, ~0L, MALLOC_OVERHEAD, IO_SIZE, 0},
+   128*1024L, IO_SIZE*2+MALLOC_OVERHEAD, SSIZE_MAX, MALLOC_OVERHEAD, IO_SIZE,
+   0},
   {"read_only", OPT_READONLY,
    "Make all non-temporary tables read-only, with the exception for replication (slave) threads and users with the SUPER privilege",
    (gptr*) &opt_readonly,
@@ -5858,12 +5859,12 @@ The minimum value for this variable is 4096.",
    (gptr*) &global_system_variables.read_rnd_buff_size,
    (gptr*) &max_system_variables.read_rnd_buff_size, 0,
    GET_ULONG, REQUIRED_ARG, 256*1024L, IO_SIZE*2+MALLOC_OVERHEAD,
-   ~0L, MALLOC_OVERHEAD, IO_SIZE, 0},
+   SSIZE_MAX, MALLOC_OVERHEAD, IO_SIZE, 0},
   {"record_buffer", OPT_RECORD_BUFFER,
    "Alias for read_buffer_size",
    (gptr*) &global_system_variables.read_buff_size,
    (gptr*) &max_system_variables.read_buff_size,0, GET_ULONG, REQUIRED_ARG,
-   128*1024L, IO_SIZE*2+MALLOC_OVERHEAD, ~0L, MALLOC_OVERHEAD, IO_SIZE, 0},
+   128*1024L, IO_SIZE*2+MALLOC_OVERHEAD, SSIZE_MAX, MALLOC_OVERHEAD, IO_SIZE, 0},
 #ifdef HAVE_REPLICATION
   {"relay_log_purge", OPT_RELAY_LOG_PURGE,
    "0 = do not purge relay logs. 1 = purge them as soon as they are no more needed.",