diff options
Diffstat (limited to 'src/proxymap/proxymap.c')
| -rw-r--r-- | src/proxymap/proxymap.c | 38 |
1 files changed, 35 insertions, 3 deletions
diff --git a/src/proxymap/proxymap.c b/src/proxymap/proxymap.c index abdcf3a..c0af411 100644 --- a/src/proxymap/proxymap.c +++ b/src/proxymap/proxymap.c @@ -37,7 +37,7 @@ /* .IP \(bu /* To provide single-updater functionality for lookup tables /* that do not reliably support multiple writers (i.e. all -/* file-based tables). +/* file-based tables that are not based on \fBlmdb\fR). /* .PP /* The \fBproxymap\fR(8) server implements the following requests: /* .IP "\fBopen\fR \fImaptype:mapname flags\fR" @@ -752,8 +752,10 @@ static void post_jail_init(char *service_name, char **unused_argv) if (strcmp(service_name, MAIL_SERVICE_PROXYWRITE) == 0) proxy_writer = 1; else if (strcmp(service_name, MAIL_SERVICE_PROXYMAP) != 0) - msg_fatal("service name must be one of %s or %s", - MAIL_SERVICE_PROXYMAP, MAIL_SERVICE_PROXYMAP); + msg_fatal("invalid service name: \"%s\" - " + "service name must be \"%s\" or \"%s\"", + service_name, MAIL_SERVICE_PROXYWRITE, + MAIL_SERVICE_PROXYMAP); /* * Pre-allocate buffers. @@ -841,6 +843,36 @@ int main(int argc, char **argv) */ MAIL_VERSION_STAMP_ALLOCATE; + /* + * XXX When invoked with the master.cf service name "proxywrite", the + * proxymap daemon will allow update requests. To update a table that is + * not multi-writer safe (for example, some versions of Berkeley DB), the + * "proxywrite" service should run as a single updater (i.e. a process + * limit of 1, which could be enforced below by requesting + * CA_MAIL_SERVER_SOLITARY). + * + * In the default master.cf file, the "proxywrite" service has a process + * limit of 1. Assuming that updates will be rare, this process limit + * will suffice. Latency-sensitive services such as postscreen must not + * use the proxywrite service (in fact, postscreen has a latency check + * built-in). + * + * Optimizing for multi-writer operation would suffer from all kinds of + * complexity that would make it hard to use: + * + * - The master daemon specifies the "proxywrite" service name with the -n + * command-line option. This information is not known here, before the + * multi_server_main() call. The multi_server_main() function could + * reveal process limit information to its call-back functions, and leave + * single-updater enforcement to its call-back functions. + * + * - If we really want multi-writer update support, the "proxywrite" service + * would have to parse the $proxy_write_maps value, and permit + * multi-writer operation only if all tables are multi-writer safe. That + * would require a new dict(3) method, to query each lookup table + * implementation if it is multi-writer safe, without instantiating a + * lookup table client. + */ multi_server_main(argc, argv, proxymap_service, CA_MAIL_SERVER_STR_TABLE(str_table), CA_MAIL_SERVER_POST_INIT(post_jail_init), |