[Qemu-devel] [PATCH for-2.6] block: add an 'iscsi-id' value to match -drive with -iscsi opts

["Daniel P. Berrange" <berrange@redhat.com>]

The iSCSI block driver has ability to lookup various options, in
particular authentication info, specified by the separate -iscsi
argument. It currently uses the iSCSI IQN as the ID value for this
lookup, however, this does not work for common iSCSI IQNs as they
contain characters such as ':' which are invalid for use as IDs.

This adds an optional 'iscsi-id' parameter to the iSCSI block
driver to allow an explicit ID string to be used to reference
the -iscsi arg. For example

 $QEMU \
   -iscsi id=my_initiator,user=fred,password-secret=sec0 \
   -drive driver=iscsi,iscsi-id=my_initiator,file=iscsi://somehost/iqn/1

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
 block/iscsi.c   | 35 +++++++++++++++++++++++------------
 qemu-doc.texi   | 12 +++++++++---
 qemu-options.hx |  4 ++--
 3 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/block/iscsi.c b/block/iscsi.c
index 302baf8..4b7aa91 100644
--- a/block/iscsi.c
+++ b/block/iscsi.c
@@ -1070,7 +1070,7 @@ retry:
     return 0;
 }
 
-static void parse_chap(struct iscsi_context *iscsi, const char *target,
+static void parse_chap(struct iscsi_context *iscsi, const char *id,
                        Error **errp)
 {
     QemuOptsList *list;
@@ -1085,7 +1085,7 @@ static void parse_chap(struct iscsi_context *iscsi, const char *target,
         return;
     }
 
-    opts = qemu_opts_find(list, target);
+    opts = qemu_opts_find(list, id);
     if (opts == NULL) {
         opts = QTAILQ_FIRST(&list->head);
         if (!opts) {
@@ -1123,7 +1123,7 @@ static void parse_chap(struct iscsi_context *iscsi, const char *target,
     g_free(secret);
 }
 
-static void parse_header_digest(struct iscsi_context *iscsi, const char *target,
+static void parse_header_digest(struct iscsi_context *iscsi, const char *id,
                                 Error **errp)
 {
     QemuOptsList *list;
@@ -1135,7 +1135,7 @@ static void parse_header_digest(struct iscsi_context *iscsi, const char *target,
         return;
     }
 
-    opts = qemu_opts_find(list, target);
+    opts = qemu_opts_find(list, id);
     if (opts == NULL) {
         opts = QTAILQ_FIRST(&list->head);
         if (!opts) {
@@ -1161,7 +1161,7 @@ static void parse_header_digest(struct iscsi_context *iscsi, const char *target,
     }
 }
 
-static char *parse_initiator_name(const char *target)
+static char *parse_initiator_name(const char *id)
 {
     QemuOptsList *list;
     QemuOpts *opts;
@@ -1171,7 +1171,7 @@ static char *parse_initiator_name(const char *target)
 
     list = qemu_find_opts("iscsi");
     if (list) {
-        opts = qemu_opts_find(list, target);
+        opts = qemu_opts_find(list, id);
         if (!opts) {
             opts = QTAILQ_FIRST(&list->head);
         }
@@ -1195,7 +1195,7 @@ static char *parse_initiator_name(const char *target)
     return iscsi_name;
 }
 
-static int parse_timeout(const char *target)
+static int parse_timeout(const char *id)
 {
     QemuOptsList *list;
     QemuOpts *opts;
@@ -1203,7 +1203,7 @@ static int parse_timeout(const char *target)
 
     list = qemu_find_opts("iscsi");
     if (list) {
-        opts = qemu_opts_find(list, target);
+        opts = qemu_opts_find(list, id);
         if (!opts) {
             opts = QTAILQ_FIRST(&list->head);
         }
@@ -1314,6 +1314,11 @@ static QemuOptsList runtime_opts = {
             .type = QEMU_OPT_STRING,
             .help = "URL to the iscsi image",
         },
+        {
+            .name = "iscsi-id",
+            .type = QEMU_OPT_STRING,
+            .help = "ID of the -iscsi argument"
+        },
         { /* end of list */ }
     },
 };
@@ -1452,6 +1457,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
     QemuOpts *opts;
     Error *local_err = NULL;
     const char *filename;
+    const char *iscsi_arg_id;
     int i, ret = 0, timeout = 0;
 
     opts = qemu_opts_create(&runtime_opts, NULL, 0, &error_abort);
@@ -1473,7 +1479,12 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
 
     memset(iscsilun, 0, sizeof(IscsiLun));
 
-    initiator_name = parse_initiator_name(iscsi_url->target);
+    iscsi_arg_id = qdict_get_try_str(bs->options, "iscsi-id");
+    if (!iscsi_arg_id) {
+        iscsi_arg_id = iscsi_url->target;
+    }
+
+    initiator_name = parse_initiator_name(iscsi_arg_id);
 
     iscsi = iscsi_create_context(initiator_name);
     if (iscsi == NULL) {
@@ -1499,7 +1510,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* check if we got CHAP username/password via the options */
-    parse_chap(iscsi, iscsi_url->target, &local_err);
+    parse_chap(iscsi, iscsi_arg_id, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
@@ -1515,7 +1526,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
     iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE_CRC32C);
 
     /* check if we got HEADER_DIGEST via the options */
-    parse_header_digest(iscsi, iscsi_url->target, &local_err);
+    parse_header_digest(iscsi, iscsi_arg_id, &local_err);
     if (local_err != NULL) {
         error_propagate(errp, local_err);
         ret = -EINVAL;
@@ -1523,7 +1534,7 @@ static int iscsi_open(BlockDriverState *bs, QDict *options, int flags,
     }
 
     /* timeout handling is broken in libiscsi before 1.15.0 */
-    timeout = parse_timeout(iscsi_url->target);
+    timeout = parse_timeout(iscsi_arg_id);
 #if defined(LIBISCSI_API_VERSION) && LIBISCSI_API_VERSION >= 20150621
     iscsi_set_timeout(iscsi, timeout);
 #else
diff --git a/qemu-doc.texi b/qemu-doc.texi
index 79141d3..ecfd277 100644
--- a/qemu-doc.texi
+++ b/qemu-doc.texi
@@ -1018,7 +1018,7 @@ These can also be set via a configuration file
 
 Setting the target name allows different options for different targets
 @example
-[iscsi "iqn.target.name"]
+[iscsi "someid"]
   user = "CHAP username"
   password = "CHAP password"
   initiator-name = "iqn.qemu.test:my-initiator"
@@ -1026,18 +1026,24 @@ Setting the target name allows different options for different targets
   header-digest = "CRC32C"
 @end example
 
+The ``someid'' string is referenced from the -drive argument
+using the ``iscsi-id'' parameter. If ``iscsi-id'' is not set
+then it will try to use the iSCSI IQN value as the ID, however,
+since this often contains invalid characters, using an explicit
+ID is recommended.
 
 Howto use a configuration file to set iSCSI configuration options:
 @example
 cat >iscsi.conf <<EOF
-[iscsi]
+[iscsi "my_initiator"]
   user = "me"
   password = "my password"
   initiator-name = "iqn.qemu.test:my-initiator"
   header-digest = "CRC32C"
 EOF
 
-qemu-system-i386 -drive file=iscsi://127.0.0.1/iqn.qemu.test/1 \
+qemu-system-i386 \
+    -drive file=iscsi://127.0.0.1/iqn.qemu.test/1,driver=isci,iscsi-id=my_initiator \
     -readconfig iscsi.conf
 @end example
 
diff --git a/qemu-options.hx b/qemu-options.hx
index 6106520..181df6f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2489,9 +2489,9 @@ iSCSI support is an optional feature of QEMU and only available when
 compiled and linked against libiscsi.
 ETEXI
 DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi,
-    "-iscsi [user=user][,password=password]\n"
+    "-iscsi [user=user][,password=password][,password-secret=id]\n"
     "       [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n"
-    "       [,initiator-name=initiator-iqn][,id=target-iqn]\n"
+    "       [,initiator-name=initiator-iqn][,id=id]\n"
     "       [,timeout=timeout]\n"
     "                iSCSI session parameters\n", QEMU_ARCH_ALL)
 STEXI
-- 
2.5.5