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Re: [libvirt] [PATCH v4 4/4] qemu/rbd: improve rbd device specification



On 10/28/2011 03:19 PM, Josh Durgin wrote:
From: Sage Weil<sage newdream net>

This improves the support for qemu rbd devices by adding support for a few
key features (e.g., authentication) and cleaning up the way in which
rbd configuration options are passed to qemu.

And<auth>  member of the disk source xml specifies how librbd should

s/And/An/

authenticate. The username attribute is the Ceph/RBD user to authenticate as.
The usage or uuid attributes specify which secret to use. Usage is an
arbitrary identifier local to libvirt.

The old RBD support relied on setting an environment variable to
communicate information to qemu/librbd.  Instead, pass those options
explicitly to qemu.  Update the qemu argument parsing and tests
accordingly.

Signed-off-by: Sage Weil<sage newdream net>
Signed-off-by: Josh Durgin<josh durgin dreamhost com>
---

This fixes the things Daniel mentioned.

Needs a v5, to fix memory management issues.

@@ -1495,6 +1496,159 @@ qemuSafeSerialParamValue(const char *value)
      return 0;
  }

+static int qemuBuildRBDString(virConnectPtr conn,
+                              virDomainDiskDefPtr disk,
+                              virBufferPtr opt)

Nit: We've been using this style:

static int
qemuBuildRBDString(virConnectPtr conn,
                   virDomainDiskDefPtr disk,
                   virBufferPtr opt)

+        if (sec) {
+            char *base64;
+
+            secret = (char *)conn->secretDriver->getValue(sec,&secret_size, 0,
+                                                          VIR_SECRET_GET_VALUE_INTERNAL_CALL);
+            if (secret == NULL) {
+                qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                                _("could not get the value of the secret for username %s"),
+                                disk->auth.username);
+                return -1;

Resource leak. You need to ensure virUnrefSecret(sec) gets called on this path. I'd move that particular cleanup down into the cleanup: label, and make this part goto cleanup instead of return -1.

+            }
+            /* qemu/librbd wants it base64 encoded */
+            base64_encode_alloc(secret, secret_size,&base64);
+            virBufferEscape(opt, ":", ":key=%s:auth_supported=cephx\\;none",
+                            base64);

Need to check for allocation failure of base64_encode_alloc; otherwise, you blindly passed NULL base64 to virBufferEscape, which is not portable.

+            VIR_FREE(base64);
+            VIR_FREE(secret);
+            virUnrefSecret(sec);
+        } else {
+            qemuReportError(VIR_ERR_INTERNAL_ERROR,
+                            _("rbd username '%s' specified but secret not found"),
+                            disk->auth.username);
+            return -1;
+        }
+    }
+
+    if (disk->nhosts>  0) {
+        virBufferStrcat(opt, ":mon_host=", NULL);
+        for (i = 0; i<  disk->nhosts; ++i) {
+            if (i) {
+                virBufferStrcat(opt, "\\;", NULL);

virBufferAddLit(opt, "\\;")

is more efficient than virBufferStrcat().

+            }
+            if (disk->hosts[i].port) {
+                virBufferAsprintf(opt, "%s\\:%s",
+                                  disk->hosts[i].name,
+                                  disk->hosts[i].port);
+            } else {
+                virBufferAsprintf(opt, "%s", disk->hosts[i].name);
+            }
+        }
+    }
+
+    return 0;
+}
+
+static int qemuAddRBDHost(virDomainDiskDefPtr disk, char *hostport)
+{
+    char *port;
+    int ret;
+
+    disk->nhosts++;
+    ret = VIR_REALLOC_N(disk->hosts, disk->nhosts);
+    if (ret<  0) {
+        virReportOOMError();
+        return -1;
+    }
+
+    port = strstr(hostport, "\\:");
+    if (port) {
+        *port = '\0';
+        port += 2;
+        disk->hosts[disk->nhosts-1].port = strdup(port);
+    } else {
+        disk->hosts[disk->nhosts-1].port = strdup("6789");
+    }
+    disk->hosts[disk->nhosts-1].name = strdup(hostport);

These three strdup() need to check for allocation failure.

+    return 0;
+}
+
+/* disk->src initially has everything after the rbd: prefix */
+static int qemuParseRBDString(virDomainDiskDefPtr disk)
+{
+    char *options = NULL;
+    char *p, *e, *next;
+
+    p = strchr(disk->src, ':');
+    if (p) {
+        options = strdup(p + 1);
+        *p = '\0';

Need to check for strdup() failure.

+    }
+
+    /* options */
+    if (!options)
+        return 0; /* all done */
+
+    p = options;
+    while (*p) {
+        /* find : delimiter or end of string */
+        for (e = p; *e&&  *e != ':'; ++e) {
+            if (*e == '\\') {
+                e++;
+                if (*e == '\0')
+                    break;
+            }
+        }
+        if (*e == '\0') {
+            next = e;    /* last kv pair */
+        } else {
+            next = e + 1;
+            *e = '\0';
+        }
+
+        if (STRPREFIX(p, "id=")) {
+            disk->auth.username = strdup(p + strlen("id="));

Check for allocation failure. Also, you might want to see if using strndup() on the original string is easier than copying the string, just so you can do in-place modifications of injecting NUL bytes for strdup() to work.

+        }
+        if (STRPREFIX(p, "mon_host=")) {
+            char *h, *sep;
+
+            h = p + strlen("mon_host=");
+            while (h<  e) {
+                for (sep = h; sep<  e; ++sep) {
+                    if (*sep == '\\'&&  (sep[1] == ',' ||
+                                         sep[1] == ';' ||
+                                         sep[1] == ' ')) {
+                        *sep = '\0';
+                        sep += 2;
+                        break;
+                    }
+                }
+                qemuAddRBDHost(disk, h);

Don't ignore the return value here.

+                h = sep;
+            }
+        }
+
+        p = next;
+    }
+    return 0;
+}

  char *
  qemuBuildDriveStr(virConnectPtr conn,
@@ -1614,8 +1768,10 @@ qemuBuildDriveStr(virConnectPtr conn,
                                    disk->hosts->name, disk->hosts->port);
                  break;
              case VIR_DOMAIN_DISK_PROTOCOL_RBD:
-                /* TODO: set monitor hostnames */
-                virBufferAsprintf(&opt, "file=rbd:%s,", disk->src);
+                virBufferStrcat(&opt, "file=", NULL);

virBufferAddLit(&opt, "file=") is more efficient.

+                if (qemuBuildRBDString(conn, disk,&opt)<  0)
+                    goto error;
+                virBufferStrcat(&opt, ",", NULL);

virBufferAddChar(&opt, ',') is more efficient.

@@ -5299,10 +5418,6 @@ static int qemuStringToArgvEnv(const char *args,
          const char *next;

          start = curr;
-        /* accept a space in CEPH_ARGS */
-        if (STRPREFIX(curr, "CEPH_ARGS=-m ")) {
-            start += strlen("CEPH_ARGS=-m ");
-        }

While we aren't generating CEPH_ARGS in the environment any more, I don't think we should rip out the parsing code. That is, parsing should be able to handle our older output, in addition to our new output.

+++ b/tests/qemuxml2argvdata/qemuxml2argv-disk-drive-network-rbd-auth.args
@@ -0,0 +1,6 @@
+LC_ALL=C PATH=/bin HOME=/home/test USER=test LOGNAME=test \
+/usr/bin/qemu -S -M pc -m 214 -smp 1 -nographic -monitor \
+unix:/tmp/test-monitor,server,nowait -no-acpi -boot c -drive \
+file=/dev/HostVG/QEMUGuest1,if=ide,bus=0,unit=0 -drive \
+file=rbd:pool/image:id=myname:key=QVFDVm41aE82SHpGQWhBQXEwTkN2OGp0SmNJY0UrSE9CbE1RMUE=:auth_supported=cephx\;none:mon_host=mon1.example.org\:6321\;mon2.example.org\:6322\;mon3.example.org\:6322,\

That's a rather long line - I'd suggest using backslash-newline to break it up, probably at each ':' (it's not the end of the world if you go longer than 80 columns, if absolutely necessary, but life is easier when everything just fits).


+static virSecretPtr
+fakeSecretLookupByUsage(virConnectPtr conn,
+                        int usageType ATTRIBUTE_UNUSED,
+                        const char *usageID)
+{
+    virSecretPtr ret = NULL;
+    int err;
+    if (STRNEQ(usageID, "mycluster_myname"))
+        return NULL;
+    err = VIR_ALLOC(ret);
+    if (err<  0)
+        return NULL;
+    ret->magic = VIR_SECRET_MAGIC;
+    ret->conn = conn;
+    conn->refs++;
+    ret->refs = 1;
+    ret->usageID = strdup(usageID);

Check for strdup() failure.

--
Eric Blake   eblake redhat com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org


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