[SLOF] [PATCH v2 06/11] libnet: Add functions for downloading and parsing pxelinux.cfg files

[Alexey Kardashevskiy]

On 19/5/18 1:45 am, Thomas Huth wrote:
> Booting a kernel via pxelinux.cfg files is common on x86 and also with
> ppc64 bootloaders like petitboot, so it would be nice to support this
> in SLOF, too. This patch adds functions for downloading and parsing
> such pxelinux.cfg files. See this URL for more details on pxelinux.cfg:
> https://www.syslinux.org/wiki/index.php?title=PXELINUX
> 
> Signed-off-by: Thomas Huth <thuth at redhat.com>
> ---
>  lib/libnet/Makefile   |   2 +-
>  lib/libnet/pxelinux.c | 209 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  lib/libnet/pxelinux.h |  33 ++++++++
>  3 files changed, 243 insertions(+), 1 deletion(-)
>  create mode 100644 lib/libnet/pxelinux.c
>  create mode 100644 lib/libnet/pxelinux.h
> 
> diff --git a/lib/libnet/Makefile b/lib/libnet/Makefile
> index dfefea9..a2a6570 100644
> --- a/lib/libnet/Makefile
> +++ b/lib/libnet/Makefile
> @@ -19,7 +19,7 @@ include $(TOP)/make.rules
>  CFLAGS += -I. -I.. -I../libc/include -I$(TOP)/include $(FLAG)
>  
>  SRCS =	ethernet.c ipv4.c udp.c tcp.c dns.c bootp.c dhcp.c tftp.c \
> -	ipv6.c dhcpv6.c icmpv6.c ndp.c netload.c ping.c args.c
> +	ipv6.c dhcpv6.c icmpv6.c ndp.c netload.c ping.c args.c pxelinux.c
>  
>  OBJS = $(SRCS:%.c=%.o)
>  
> diff --git a/lib/libnet/pxelinux.c b/lib/libnet/pxelinux.c
> new file mode 100644
> index 0000000..0c0b42e
> --- /dev/null
> +++ b/lib/libnet/pxelinux.c
> @@ -0,0 +1,209 @@
> +/*****************************************************************************
> + * pxelinux.cfg-style config file support.
> + *
> + * See https://www.syslinux.org/wiki/index.php?title=PXELINUX for information
> + * about the pxelinux config file layout.
> + *
> + * Copyright 2018 Red Hat, Inc.
> + *
> + * This program and the accompanying materials are made available under the
> + * terms of the BSD License which accompanies this distribution, and is
> + * available at http://www.opensource.org/licenses/bsd-license.php
> + *
> + * Contributors:
> + *     Thomas Huth, Red Hat Inc. - initial implementation
> + *****************************************************************************/
> +
> +#include <stdio.h>
> +#include <string.h>
> +#include "tftp.h"
> +#include "pxelinux.h"
> +
> +/**
> + * Call tftp() and report errors (excet "file-not-found" errors)
> + */
> +static int pxelinux_tftp_load(filename_ip_t *fnip, void *buffer, int len)
> +{
> +	tftp_err_t tftp_err;
> +	int rc;
> +
> +	rc = tftp(fnip, buffer, len, &tftp_err);
> +
> +	if (rc > 0) {
> +		printf("\r  TFTP: Received %s (%d bytes)\n",
> +		       fnip->filename, rc);
> +	} else if (rc == -3) {
> +		/* Ignore file-not-found (since we are probing the files)
> +		 * and simply erase the "Receiving data:  0 KBytes" string */
> +		printf("\r                           \r");
> +	} else {
> +		const char *errstr = NULL;
> +		rc = tftp_get_error_info(fnip, &tftp_err, rc, &errstr, NULL);
> +		if (errstr)
> +			printf("\r  TFTP error: %s\n", errstr);
> +	}
> +
> +	return rc;
> +}
> +
> +/**
> + * Try to load a pxelinux.cfg file by probing the possible file names.
> + */
> +static int pxelinux_load_cfg(filename_ip_t *fn_ip, uint8_t *mac, uint8_t *uuid,
> +                             char *cfgbuf, int cfgbufsize)
> +{
> +	int rc, idx;
> +	char basedir[sizeof(fn_ip->filename) - 40];
> +	char *slash;
> +
> +	cfgbuf[cfgbufsize - 1] = 0;  /* Make sure it is NUL-terminated */
> +
> +	/* Did we get a usable base directory via DHCP? */
> +	slash = strrchr(fn_ip->filename, '/');
> +	if (slash && slash - fn_ip->filename < sizeof(basedir) - 1) {
> +		slash[1] = 0;
> +		strcpy(basedir, fn_ip->filename);
> +	} else {
> +		strcpy(basedir, "pxelinux.cfg/");
> +	}
> +
> +	printf("Trying pxelinux.cfg files...\n");
> +
> +	/* Try to load config file with name based on the VM UUID */
> +	if (uuid) {
> +		sprintf(fn_ip->filename, "%s%02x%02x%02x%02x-%02x%02x-"
> +			"%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", basedir,
> +			uuid[0], uuid[1], uuid[2], uuid[3], uuid[4], uuid[5],
> +			uuid[6], uuid[7], uuid[8], uuid[9], uuid[10], uuid[11],
> +			uuid[12], uuid[13], uuid[14], uuid[15]);
> +		rc = pxelinux_tftp_load(fn_ip, cfgbuf, cfgbufsize - 1);
> +		if (rc > 0) {
> +			return rc;
> +		}
> +	}
> +
> +	/* Look for config file with MAC address in its name */
> +	sprintf(fn_ip->filename, "%s%02x-%02x-%02x-%02x-%02x-%02x", basedir,


This is missing ARP type "1". Should be: "%s01-%02x-%02x-%02x-%02x-%02x-%02x"




-- 
Alexey