From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Diego Domingos <diegodo@br.ibm.com>

Date: Mon, 14 Dec 2020 17:47:16 +0100

Subject: [PATCH] ieee1275/powerpc: enables device mapper discovery

this patch enables the device mapper discovery on ofpath.c. Currently,

when we are dealing with a device like /dev/dm-* the ofpath returns null

since there is no function implemented to handle this case.

This patch implements a function that will look into /sys/block/dm-*

devices and search recursively inside slaves directory to find the root

disk.

Signed-off-by: Diego Domingos <diegodo@br.ibm.com>

---

 grub-core/osdep/linux/ofpath.c | 64 +++++++++++++++++++++++++++++++++++++++++-

 1 file changed, 63 insertions(+), 1 deletion(-)

diff --git a/grub-core/osdep/linux/ofpath.c b/grub-core/osdep/linux/ofpath.c

index 0f5d54e9f..cc849d9c9 100644

--- a/grub-core/osdep/linux/ofpath.c

+++ b/grub-core/osdep/linux/ofpath.c

@@ -37,6 +37,7 @@

 #include <fcntl.h>

 #include <errno.h>

 #include <ctype.h>

+#include <dirent.h>

 #ifdef __sparc__

 typedef enum

@@ -755,13 +756,74 @@ strip_trailing_digits (const char *p)

   return new;

 }

+static char *

+get_slave_from_dm(const char * device){

+  char *curr_device, *tmp;

+  char *directory;

+  char *ret = NULL;

+

+  directory = grub_strdup (device);

+  tmp = get_basename(directory);

+  curr_device = grub_strdup (tmp);

+  *tmp = '\0';

+

+  /* Recursively check for slaves devices so we can find the root device */

+  while ((curr_device[0] == 'd') && (curr_device[1] == 'm') && (curr_device[2] == '-')){

+    DIR *dp;

+    struct dirent *ep;

+    char* device_path;

+

+    device_path = grub_xasprintf ("/sys/block/%s/slaves", curr_device);

+    dp = opendir(device_path);

+    free(device_path);

+

+    if (dp != NULL)

+    {

+      ep = readdir (dp);

+      while (ep != NULL){

+

+	/* avoid some system directories */

+        if (!strcmp(ep->d_name,"."))

+            goto next_dir;

+        if (!strcmp(ep->d_name,".."))

+            goto next_dir;

+

+	free (curr_device);

+	free (ret);

+	curr_device = grub_strdup (ep->d_name);

+	ret = grub_xasprintf ("%s%s", directory, curr_device);

+	break;

+

+        next_dir:

+         ep = readdir (dp);

+         continue;

+      }

+      closedir (dp);

+    }

+    else

+      grub_util_warn (_("cannot open directory `%s'"), device_path);

+  }

+

+  free (directory);

+  free (curr_device);

+

+  return ret;

+}

+

 char *

 grub_util_devname_to_ofpath (const char *sys_devname)

 {

-  char *name_buf, *device, *devnode, *devicenode, *ofpath;

+  char *name_buf, *device, *devnode, *devicenode, *ofpath, *realname;

   name_buf = xrealpath (sys_devname);

+  realname = get_slave_from_dm (name_buf);

+  if (realname)

+    {

+      free (name_buf);

+      name_buf = realname;

+    }

+

   device = get_basename (name_buf);

   devnode = strip_trailing_digits (name_buf);

   devicenode = strip_trailing_digits (device);