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Re: [libvirt] [PATCH 10/11] util: Add a util to guess the scsi host name with specified "parent"



On 20/06/13 02:53, John Ferlan wrote:
On 06/07/2013 01:03 PM, Osier Yang wrote:
Not really guessing, it returns host name of the scsi host which has
smallest unique_id.
---
  src/libvirt_private.syms |   1 +
  src/util/virutil.c       | 122 +++++++++++++++++++++++++++++++++++++++++++++++
  src/util/virutil.h       |   4 ++
  tests/utiltest.c         |  27 +++++++++++
  4 files changed, 154 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 27fb0b5..ec85079 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1948,6 +1948,7 @@ virGetUserDirectory;
  virGetUserID;
  virGetUserName;
  virGetUserRuntimeDirectory;
+virGuessStableScsiHostName;
  virHexToBin;
  virIndexToDiskName;
  virIsCapableFCHost;
diff --git a/src/util/virutil.c b/src/util/virutil.c
index a80574f..7f36e27 100644
--- a/src/util/virutil.c
+++ b/src/util/virutil.c
@@ -2256,6 +2256,120 @@ cleanup:
      }
      return ret;
  }
+
+static int
+virGuessStableScsiHostNameCallback(const char *fpath,
+                                   void *opaque)
+{
+    const char *filename = opaque;
+    char *p = NULL;
+
+    p = strrchr(fpath, '/');
+    p++;
+
+    if (STREQ(p, filename))
+        return 0;
+    return -1;
+}
+
+/**
+ * virGuessStableScsiHostName:
+ * @sysfs_prefix: The directory path where starts to traverse, defaults
+ *                to SYSFS_BUS_PCI_DEVICES.
+ * @addr: The parent's PCI address
+ *
+ * Returns the host name (e.g. host10) of the scsi host whose parent
+ * has address @addr, and "unique_id" has the smallest value on success.
+ * Or NULL on failure.
It is up to the caller to free the memory returned.

Yes, will add


+ */
+char *
+virGuessStableScsiHostName(const char *sysfs_prefix,
+                           const char *address)
+{
+    const char *prefix = sysfs_prefix ? sysfs_prefix : SYSFS_BUS_PCI_DEVICES;
+    unsigned int flags = 0;
+    char **paths = NULL;
+    int npaths = 0;
+    char *smallest_path = NULL;
+    unsigned int smallest;
+    char *dir = NULL;
+    char *buf = NULL;
+    char *p1 = NULL;
+    char *p2 = NULL;
+    char *ret = NULL;
+    int i;
+
+    const char *filename = "unique_id";
+
+    if (virAsprintf(&dir, "%s/%s", prefix, address) < 0) {
+        virReportOOMError();
+        return NULL;
+    }
+
+    flags |= (VIR_TRAVERSE_DIRECTORY_IGNORE_HIDDEN_FILES |
+              VIR_TRAVERSE_DIRECTORY_FALL_THROUGH);
+
+    if ((npaths = virTraverseDirectory(dir, 4, flags,
+                                       virGuessStableScsiHostNameCallback,
+                                       NULL, (void *)filename, &paths)) < 0)
+        goto cleanup;
+
 From here...

+    smallest_path = paths[0];
+    if (virFileReadAll(paths[0], 1024, &buf) < 0)
+        goto cleanup;
+
+    if ((p1 = strchr(buf, '\n')))
+        *p1 = '\0';
+
+    if (virStrToLong_ui(buf, NULL, 10, &smallest) < 0)
+        goto cleanup;
+
+    VIR_FREE(buf);
+    buf = NULL;
...to here isn't necessary... and if you keep it, then the loop below
goes from 1 to npaths since 0 is already covered...

Hm, stupid mistake...  Thanks.

Osier


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