[SLOF] [PATCH 6/9] libnet: Add functions for downloading and parsing pxelinux.cfg files
Thomas Huth
thuth at redhat.com
Fri May 18 03:40:53 AEST 2018
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..5ba2653
--- /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, 1, 1428);
+
+ 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 {
+ 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,
+ mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
+ rc = pxelinux_tftp_load(fn_ip, cfgbuf, cfgbufsize - 1);
+ if (rc > 0) {
+ return rc;
+ }
+
+ /* Look for config file with IP address in its name */
+ if (fn_ip->ip_version == 4) {
+ for (idx = 0; idx <= 7; idx++) {
+ sprintf(fn_ip->filename, "%s%02X%02X%02X%02X", basedir,
+ (fn_ip->own_ip >> 24) & 0xff,
+ (fn_ip->own_ip >> 16) & 0xff,
+ (fn_ip->own_ip >> 8) & 0xff,
+ fn_ip->own_ip & 0xff);
+ fn_ip->filename[strlen(fn_ip->filename) - idx] = 0;
+ rc = pxelinux_tftp_load(fn_ip, cfgbuf, cfgbufsize - 1);
+ if (rc > 0) {
+ return rc;
+ }
+ }
+ }
+
+ /* Try "default" config file */
+ sprintf(fn_ip->filename, "%sdefault", basedir);
+ rc = pxelinux_tftp_load(fn_ip, cfgbuf, cfgbufsize - 1);
+
+ return rc;
+}
+
+/**
+ * Parse a pxelinux-style configuration file.
+ * @param cfg Pointer to the buffer with contents of the config file
+ * @param cfgsize Size of the cfg buffer
+ * @param entries Pointer to array where the results should be put into
+ * @param max_entries Number of available slots in the entries array
+ * @param def_ent Used to return the index of the default entry
+ * @return Number of valid entries
+ */
+int pxelinux_parse_cfg(char *cfg, int cfgsize, struct lkia *entries,
+ int max_entries, int *def_ent)
+{
+ int num_entries = 0;
+ char *ptr = cfg, *nextptr, *eol, *arg;
+ char *defaultlabel = NULL;
+
+ *def_ent = 0;
+
+ while (ptr < cfg + cfgsize && num_entries < max_entries) {
+ eol = strchr(ptr, '\n');
+ if (!eol) {
+ eol = cfg + cfgsize;
+ }
+ nextptr = eol + 1;
+ do {
+ *eol-- = '\0'; /* Remove spaces, tabs and returns */
+ } while (eol >= ptr &&
+ (*eol == '\r' || *eol == ' ' || *eol == '\t'));
+ while (*ptr == ' ' || *ptr == '\t') {
+ ptr++;
+ }
+ if (*ptr == 0 || *ptr == '#') {
+ goto nextline; /* Ignore comments and empty lines */
+ }
+ arg = strchr(ptr, ' '); /* Search space between cmnd and arg */
+ if (!arg) {
+ arg = strchr(ptr, '\t');
+ }
+ if (!arg) {
+ printf("Failed to parse this line:\n %s\n", ptr);
+ goto nextline;
+ }
+ *arg++ = 0;
+ while (*arg == ' ' || *arg == '\t') {
+ arg++;
+ }
+ if (!strcasecmp("default", ptr)) {
+ defaultlabel = arg;
+ } else if (!strcasecmp("label", ptr)) {
+ entries[num_entries].label = arg;
+ if (defaultlabel && !strcmp(arg, defaultlabel)) {
+ *def_ent = num_entries;
+ }
+ num_entries++;
+ } else if (!strcasecmp("kernel", ptr) && num_entries > 0) {
+ entries[num_entries - 1].kernel = arg;
+ } else if (!strcasecmp("initrd", ptr) && num_entries > 0) {
+ entries[num_entries - 1].initrd = arg;
+ } else if (!strcasecmp("append", ptr) && num_entries > 0) {
+ entries[num_entries - 1].append = arg;
+ } else {
+ printf("Command '%s' is not supported.\n", ptr);
+ }
+nextline:
+ ptr = nextptr;
+ }
+
+ return num_entries;
+}
+
+/**
+ * Try to load and parse a pxelinux-style configuration file.
+ * @param fn_ip must contain server and client IP information
+ * @param mac MAC address which should be used for probing
+ * @param uuid UUID which should be used for probing (can be NULL)
+ * @param cfgbuf Pointer to the buffer where config file should be loaded
+ * @param cfgsize Size of the cfgbuf buffer
+ * @param entries Pointer to array where the results should be put into
+ * @param max_entries Number of available slots in the entries array
+ * @param def_ent Used to return the index of the default entry
+ * @return Number of valid entries
+ */
+int pxelinux_load_parse_cfg(filename_ip_t *fn_ip, uint8_t *mac, uint8_t *uuid,
+ char *cfgbuf, int cfgsize, struct lkia *entries,
+ int max_entries, int *def_ent)
+{
+ int rc;
+
+ rc = pxelinux_load_cfg(fn_ip, mac, uuid, cfgbuf, cfgsize);
+ if (rc < 0)
+ return rc;
+
+ return pxelinux_parse_cfg(cfgbuf, rc, entries, max_entries, def_ent);
+}
diff --git a/lib/libnet/pxelinux.h b/lib/libnet/pxelinux.h
new file mode 100644
index 0000000..9fd1b2f
--- /dev/null
+++ b/lib/libnet/pxelinux.h
@@ -0,0 +1,33 @@
+/*****************************************************************************
+ * Definitions for pxelinux-style config file support
+ *
+ * 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
+ *****************************************************************************/
+
+#ifndef LIBNET_PXELINUX_H
+#define LIBNET_PXELINUX_H
+
+/* This structure holds the data from one pxelinux.cfg file entry */
+struct lkia {
+ const char *label;
+ const char *kernel;
+ const char *initrd;
+ const char *append;
+};
+
+int pxelinux_parse_cfg(char *cfg, int cfgsize, struct lkia *entries,
+ int max_entries, int *def_ent);
+int pxelinux_load_parse_cfg(filename_ip_t *fn_ip, uint8_t *mac, uint8_t *uuid,
+ char *cfgbuf, int cfgsize, struct lkia *entries,
+ int max_entries, int *def_ent);
+
+
+#endif
--
1.8.3.1
More information about the SLOF
mailing list