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author | Michael Brown | 2007-01-18 23:38:13 +0100 |
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committer | Michael Brown | 2007-01-18 23:38:13 +0100 |
commit | 4e3976711dec26ba1f462f19c4b865dea3dbe4d7 (patch) | |
tree | fab4b8042cdc2e01adc2b43f5f816611e5978068 /src/core/resolv.c | |
parent | When an async operation dies, orphan its children. (diff) | |
download | ipxe-4e3976711dec26ba1f462f19c4b865dea3dbe4d7.tar.gz ipxe-4e3976711dec26ba1f462f19c4b865dea3dbe4d7.tar.xz ipxe-4e3976711dec26ba1f462f19c4b865dea3dbe4d7.zip |
A working name resolution framework
Diffstat (limited to 'src/core/resolv.c')
-rw-r--r-- | src/core/resolv.c | 133 |
1 files changed, 117 insertions, 16 deletions
diff --git a/src/core/resolv.c b/src/core/resolv.c index eb01a309..61bdfb09 100644 --- a/src/core/resolv.c +++ b/src/core/resolv.c @@ -1,33 +1,134 @@ -#include "resolv.h" +/* + * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include <gpxe/in.h> +#include <gpxe/resolv.h> +/** @file + * + * Name resolution + * + */ + +static struct async_operations resolv_async_operations; + +/** Registered name resolvers */ static struct resolver resolvers[0] - __table_start ( struct resolver, resolver ); + __table_start ( struct resolver, resolvers ); static struct resolver resolvers_end[0] - __table_end ( struct resolver, resolver ); + __table_end ( struct resolver, resolvers ); -/* - * Resolve a name (which may be just a dotted quad IP address) to an - * IP address. +/** + * Start name resolution * + * @v name Host name to resolve + * @v sa Socket address to fill in + * @v parent Parent asynchronous operation + * @ret rc Return status code */ -int resolv ( struct in_addr *address, const char *name ) { +int resolv ( const char *name, struct sockaddr *sa, struct async *parent ) { + struct resolution *resolution; struct resolver *resolver; + struct sockaddr_in *sin = ( struct sockaddr_in * ) sa; + struct in_addr in; + int rc = -ENXIO; + + /* Allocate and populate resolution structure */ + resolution = malloc ( sizeof ( *resolution ) ); + if ( ! resolution ) + return -ENOMEM; + async_init ( &resolution->async, &resolv_async_operations, parent ); /* Check for a dotted quad IP address first */ - if ( inet_aton ( name, address ) ) { - DBG ( "RESOLV saw valid IP address %s\n", name ); - return 1; + if ( inet_aton ( name, &in ) != 0 ) { + DBGC ( resolution, "RESOLV %p saw valid IP address %s\n", + resolution, name ); + sin->sin_family = AF_INET; + sin->sin_addr = in; + async_done ( &resolution->async, 0 ); + return 0; } - /* Try any compiled-in name resolution modules */ + /* Start up all resolvers */ for ( resolver = resolvers ; resolver < resolvers_end ; resolver++ ) { - if ( resolver->resolv ( address, name ) ) { - DBG ( "RESOLV resolved \"%s\" to %@ using %s\n", - name, address->s_addr, resolver->name ); - return 1; + if ( ( rc = resolver->resolv ( name, sa, + &resolution->async ) ) != 0 ) { + DBGC ( resolution, "RESOLV %p could not start %s: " + "%s\n", resolution, resolver->name, + strerror ( rc ) ); + /* Continue to try other resolvers */ + continue; } + (resolution->pending)++; } + if ( ! resolution->pending ) + goto err; - DBG ( "RESOLV failed to resolve %s\n", name ); return 0; + + err: + async_uninit ( &resolution->async ); + free ( resolution ); + return rc; } + +/** + * Handle child name resolution completion + * + * @v async Name resolution asynchronous operation + * @v signal SIGCHLD + */ +static void resolv_sigchld ( struct async *async, + enum signal signal __unused ) { + struct resolution *resolution = + container_of ( async, struct resolution, async ); + int rc; + + /* If this child succeeded, kill all the others and return */ + async_wait ( async, &rc, 1 ); + if ( rc == 0 ) { + async_signal_children ( async, SIGKILL ); + async_done ( async, 0 ); + return; + } + + /* If we have no children left, return failure */ + if ( --(resolution->pending) == 0 ) + async_done ( async, -ENXIO ); +} + +/** + * Free name resolution structure + * + * @v async Asynchronous operation + */ +static void resolv_reap ( struct async *async ) { + free ( container_of ( async, struct resolution, async ) ); +} + +/** Name resolution asynchronous operations */ +static struct async_operations resolv_async_operations = { + .reap = resolv_reap, + .signal = { + [SIGCHLD] = resolv_sigchld, + }, +}; |