From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Paulo Flabiano Smorigo <pfsmorigo@br.ibm.com>

Date: Tue, 27 Nov 2012 17:22:07 -0200

Subject: [PATCH] Search for specific config file for netboot

This patch implements a search for a specific configuration when the config

file is on a remoteserver. It uses the following order:

   1) DHCP client UUID option.

   2) MAC address (in lower case hexadecimal with dash separators);

   3) IP (in upper case hexadecimal) or IPv6;

   4) The original grub.cfg file.

This procedure is similar to what is used by pxelinux and yaboot:

http://www.syslinux.org/wiki/index.php/PXELINUX#config

This should close the bugzilla:

https://bugzilla.redhat.com/show_bug.cgi?id=873406

---

 grub-core/net/net.c     | 118 ++++++++++++++++++++++++++++++++++++++++++++++++

 grub-core/normal/main.c |  18 ++++++--

 include/grub/net.h      |   3 ++

 3 files changed, 135 insertions(+), 4 deletions(-)

diff --git a/grub-core/net/net.c b/grub-core/net/net.c

index 10773fc3435..0769bf850d3 100644

--- a/grub-core/net/net.c

+++ b/grub-core/net/net.c

@@ -1735,6 +1735,124 @@ grub_net_restore_hw (void)

   return GRUB_ERR_NONE;

 }

+grub_err_t

+grub_net_search_configfile (char *config)

+{

+  grub_size_t config_len;

+  char *suffix;

+

+  auto int search_through (grub_size_t num_tries, grub_size_t slice_size);

+  int search_through (grub_size_t num_tries, grub_size_t slice_size)

+    {

+      while (num_tries-- > 0)

+        {

+	  grub_dprintf ("net", "probe %s\n", config);

+

+          grub_file_t file;

+          file = grub_file_open (config);

+

+          if (file)

+            {

+              grub_file_close (file);

+              grub_dprintf ("net", "found!\n");

+              return 0;

+            }

+          else

+            {

+              if (grub_errno == GRUB_ERR_IO)

+                grub_errno = GRUB_ERR_NONE;

+            }

+

+          if (grub_strlen (suffix) < slice_size)

+            break;

+

+          config[grub_strlen (config) - slice_size] = '\0';

+        }

+

+      return 1;

+    }

+

+  config_len = grub_strlen (config);

+  config[config_len] = '-';

+  suffix = config + config_len + 1;

+

+  struct grub_net_network_level_interface *inf;

+  FOR_NET_NETWORK_LEVEL_INTERFACES (inf)

+    {

+      /* By the Client UUID. */

+

+      char client_uuid_var[sizeof ("net_") + grub_strlen (inf->name) +

+                           sizeof ("_clientuuid") + 1];

+      grub_snprintf (client_uuid_var, sizeof (client_uuid_var),

+                     "net_%s_clientuuid", inf->name);

+

+      const char *client_uuid;

+      client_uuid = grub_env_get (client_uuid_var);

+

+      if (client_uuid)

+        {

+          grub_strcpy (suffix, client_uuid);

+          if (search_through (1, 0) == 0) return GRUB_ERR_NONE;

+        }

+

+      /* By the MAC address. */

+

+      /* Add ethernet type */

+      grub_strcpy (suffix, "01-");

+

+      grub_net_hwaddr_to_str (&inf->hwaddress, suffix + 3);

+

+      char *ptr;

+      for (ptr = suffix; *ptr; ptr++)

+        if (*ptr == ':')

+          *ptr = '-';

+

+      if (search_through (1, 0) == 0) return GRUB_ERR_NONE;

+

+      /* By IP address */

+

+      switch ((&inf->address)->type)

+        {

+        case GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4:

+            {

+              grub_uint32_t n = grub_be_to_cpu32 ((&inf->address)->ipv4);

+              grub_snprintf (suffix, GRUB_NET_MAX_STR_ADDR_LEN, "%02X%02X%02X%02X", \

+                             ((n >> 24) & 0xff), ((n >> 16) & 0xff), \

+                             ((n >> 8) & 0xff), ((n >> 0) & 0xff));

+

+              if (search_through (8, 1) == 0) return GRUB_ERR_NONE;

+              break;

+            }

+        case GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV6:

+            {

+              char buf[GRUB_NET_MAX_STR_ADDR_LEN];

+              struct grub_net_network_level_address base;

+              base.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV6;

+              grub_memcpy (&base.ipv6, ((&inf->address)->ipv6), 16);

+              grub_net_addr_to_str (&base, buf);

+

+              for (ptr = buf; *ptr; ptr++)

+                if (*ptr == ':')

+                  *ptr = '-';

+

+              grub_snprintf (suffix, GRUB_NET_MAX_STR_ADDR_LEN, "%s", buf);

+              if (search_through (1, 0) == 0) return GRUB_ERR_NONE;

+              break;

+            }

+        case GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV:

+          return grub_error (GRUB_ERR_BUG, "shouldn't reach here");

+        default:

+          return grub_error (GRUB_ERR_BUG,

+                             "unsupported address type %d", (&inf->address)->type);

+        }

+    }

+

+  /* Remove the remaining minus sign at the end. */

+  config[config_len] = '\0';

+

+  return GRUB_ERR_NONE;

+}

+

 static struct grub_preboot *fini_hnd;

 static grub_command_t cmd_addaddr, cmd_deladdr, cmd_addroute, cmd_delroute;

diff --git a/grub-core/normal/main.c b/grub-core/normal/main.c

index 759c475c4d9..b2654ef62e8 100644

--- a/grub-core/normal/main.c

+++ b/grub-core/normal/main.c

@@ -33,6 +33,7 @@

 #include <grub/charset.h>

 #include <grub/script_sh.h>

 #include <grub/bufio.h>

+#include <grub/net.h>

 #ifdef GRUB_MACHINE_IEEE1275

 #include <grub/ieee1275/ieee1275.h>

 #endif

@@ -365,10 +366,19 @@ grub_cmd_normal (struct grub_command *cmd __attribute__ ((unused)),

       prefix = grub_env_get ("prefix");

       if (prefix)

-	{

-	  config = grub_xasprintf ("%s/grub.cfg", prefix);

-	  if (! config)

-	    goto quit;

+        {

+          grub_size_t config_len;

+          config_len = grub_strlen (prefix) +

+                      sizeof ("/grub.cfg-XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX");

+          config = grub_malloc (config_len);

+

+          if (! config)

+            goto quit;

+

+          grub_snprintf (config, config_len, "%s/grub.cfg", prefix);

+

+          if (grub_strncmp (prefix + 1, "tftp", sizeof ("tftp") - 1) == 0)

+            grub_net_search_configfile (config);

 	  grub_enter_normal_mode (config);

 	  grub_free (config);

diff --git a/include/grub/net.h b/include/grub/net.h

index e266bae23f4..50d62ab0c8c 100644

--- a/include/grub/net.h

+++ b/include/grub/net.h

@@ -566,4 +566,7 @@ extern char *grub_net_default_server;

 #define VLANTAG_IDENTIFIER 0x8100

+grub_err_t

+grub_net_search_configfile (char *config);

+

 #endif /* ! GRUB_NET_HEADER */