Cannot draw() a MyGIS layer more than once

[rparsons@…]

When rendering layers that are sourced from a MyGIS (mysql) source, draw() 
cannot be called more than once. Doing so results in a Segmentation Fault.

This phenomenon occurs because of the way MySQL connection parameters are 
parsed from the layer's 'connection' property. An examination of the code 
(around line 374 in mapmygis.c) shows that the connection parameters are 
parsed by this code:

(1) delim = strdup(":");
(2) DB_HOST = strdup(strtok(layer->connection, delim));
(3) DB_USER = strdup(strtok(NULL, delim));
(4) DB_PASSWD = strdup(strtok(NULL, delim));
(5) DB_DATABASE = strdup(strtok(NULL, delim));
(6) DB_DATATYPE = strdup(strtok(NULL, delim));

This code works fine the first time draw() is called, however subsequent calls 
results in a SIGSEGV being thrown at line (3). This occurs because strtok() 
modifies its first argument (per the strtok() man page), resulting in layer-
>connection being truncated at the first colon. When line (3) is encountered 
the SIGSEV in generated from libc because strtok() presumably returns NULL. 
Since the connection string is modified by the first run through this routine, 
subsequent calls fail.

There are a variety of potential fixes, however, this is what I did:

char* tempcon;
...
...
delim = strdup(":");
tempcon=strdup(layer->connection);
DB_HOST = strdup(strtok(tempcon, delim));
DB_USER = strdup(strtok(NULL, delim));
DB_PASSWD = strdup(strtok(NULL, delim));
DB_DATABASE = strdup(strtok(NULL, delim));
DB_DATATYPE = strdup(strtok(NULL, delim));

As a quickie solution I simply strdup() the layer->connection string to a 
temporary location then tokenize from there. This prevents corruption of the 
original connection string so that subsequent calls do not fail.

Thank you to all of the developers for your hard work on this remarkable 
product.

- Rob Parsons

[tbonfort]

mygis support has been removed. use ogr now.