Re: [Qemu-devel] [PATCH] iSCSI: add configuration variables for iSCSI

[Kevin Wolf]

Am 25.01.2012 23:39, schrieb Ronnie Sahlberg:
> This patch adds configuration variables for iSCSI to set
> initiator-name to use when logging in to the target,
> which type of header-digest to negotiate with the target
> and username and password for CHAP authentication.
> 
> This allows specifying a initiator-name either from the command line
> -iscsi initiator-name=iqn.2004-01.com.example:test
> or from a configuration file included with -readconfig
>     [iscsi]
>       initiator-name = iqn.2004-01.com.example:test
>       header-digest = CRC32C|CRC32C-NONE|NONE-CRC32C|NONE
>       user = CHAP username
>       password = CHAP password
> 
> If you use several different targets, you can also configure this on a per
> target basis by using a group name:
>     [iscsi "iqn.target.name"]
>     ...
> 
> The configuration file can be read using -readconfig.
> Example :
> qemu-system-i386 -drive file=iscsi://127.0.0.1/iqn.ronnie.test/1
>  -readconfig iscsi.conf
> 
> Signed-off-by: Ronnie Sahlberg <address@hidden>
> ---
>  block/iscsi.c   |  139 
> +++++++++++++++++++++++++++++++++++++++++++++++++++----
>  qemu-config.c   |   27 +++++++++++
>  qemu-doc.texi   |   54 +++++++++++++++++++++-
>  qemu-options.hx |   16 +++++--
>  vl.c            |    8 +++
>  5 files changed, 229 insertions(+), 15 deletions(-)
> 
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 938c568..bd3ca11 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -455,6 +455,109 @@ iscsi_connect_cb(struct iscsi_context *iscsi, int 
> status, void *command_data,
>      }
>  }
>  
> +static int parse_chap(struct iscsi_context *iscsi, const char *target)
> +{
> +    QemuOptsList *list;
> +    QemuOpts *opts;
> +    const char *user = NULL;
> +    const char *password = NULL;
> +

The pattern from here...

> +    list = qemu_find_opts("iscsi");
> +    if (!list) {
> +        return 0;
> +    }
> +
> +    opts = qemu_opts_find(list, target);
> +    if (opts == NULL) {
> +        opts = QTAILQ_FIRST(&list->head);
> +        if (!opts) {
> +            return 0;
> +        }
> +    }

...to here repeats in all three parse functions. Would probably be worth
having a function for it.

> +
> +    user = qemu_opt_get(opts, "user");
> +    if (!user) {
> +        return 0;
> +    }
> +
> +    password = qemu_opt_get(opts, "password");
> +    if (!password) {
> +        error_report("CHAP username specified but no password was given");
> +        return -1;
> +    }
> +
> +    if (iscsi_set_initiator_username_pwd(iscsi, user, password)) {
> +        error_report("Failed to set initiator username and password");
> +        return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +static void parse_header_digest(struct iscsi_context *iscsi, const char 
> *target)
> +{
> +    QemuOptsList *list;
> +    QemuOpts *opts;
> +    const char *digest = NULL;
> +
> +    list = qemu_find_opts("iscsi");
> +    if (!list) {
> +        return;
> +    }
> +
> +    opts = qemu_opts_find(list, target);
> +    if (opts == NULL) {
> +        opts = QTAILQ_FIRST(&list->head);
> +        if (!opts) {
> +            return;
> +        }
> +    }
> +
> +    digest = qemu_opt_get(opts, "header-digest");
> +    if (!digest) {
> +        return;
> +    }
> +
> +    if (!strcmp(digest, "CRC32C")) {
> +        iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_CRC32C);
> +    } else if (!strcmp(digest, "NONE")) {
> +        iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE);
> +    } else if (!strcmp(digest, "CRC32C-NONE")) {
> +        iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_CRC32C_NONE);
> +    } else if (!strcmp(digest, "NONE-CRC32C")) {
> +        iscsi_set_header_digest(iscsi, ISCSI_HEADER_DIGEST_NONE_CRC32C);
> +    } else {
> +        error_report("Invalid header-digest setting : %s", digest);
> +    }
> +}
> +
> +static char *parse_initiator_name(const char *target)
> +{
> +    QemuOptsList *list;
> +    QemuOpts *opts;
> +    const char *name = NULL;
> +
> +    list = qemu_find_opts("iscsi");
> +    if (!list) {
> +        return g_strdup("iqn.2008-11.org.linux-kvm");
> +    }
> +
> +    opts = qemu_opts_find(list, target);
> +    if (opts == NULL) {
> +        opts = QTAILQ_FIRST(&list->head);
> +        if (!opts) {
> +            return g_strdup("iqn.2008-11.org.linux-kvm");
> +        }
> +    }
> +
> +    name = qemu_opt_get(opts, "initiator-name");
> +    if (!name) {
> +        return g_strdup("iqn.2008-11.org.linux-kvm");
> +    }
> +
> +    return g_strdup(name);
> +}

Why do you need to strdup the strings? They look all pretty constant. An
additional advantage would be...

> +
>  /*
>   * We support iscsi url's on the form
>   * iscsi://[<username>%<password>@]<host>[:<port>]/<targetname>/<lun>
> @@ -465,6 +568,7 @@ static int iscsi_open(BlockDriverState *bs, const char 
> *filename, int flags)
>      struct iscsi_context *iscsi = NULL;
>      struct iscsi_url *iscsi_url = NULL;
>      struct IscsiTask task;
> +    char *initiator_name = NULL;
>      int ret;
>  
>      if ((BDRV_SECTOR_SIZE % 512) != 0) {
> @@ -474,16 +578,6 @@ static int iscsi_open(BlockDriverState *bs, const char 
> *filename, int flags)
>          return -EINVAL;
>      }
>  
> -    memset(iscsilun, 0, sizeof(IscsiLun));
> -
> -    /* Should really append the KVM name after the ':' here */
> -    iscsi = iscsi_create_context("iqn.2008-11.org.linux-kvm:");
> -    if (iscsi == NULL) {
> -        error_report("iSCSI: Failed to create iSCSI context.");
> -        ret = -ENOMEM;
> -        goto failed;
> -    }
> -
>      iscsi_url = iscsi_parse_full_url(iscsi, filename);
>      if (iscsi_url == NULL) {
>          error_report("Failed to parse URL : %s %s", filename,
> @@ -492,6 +586,17 @@ static int iscsi_open(BlockDriverState *bs, const char 
> *filename, int flags)
>          goto failed;
>      }
>  
> +    memset(iscsilun, 0, sizeof(IscsiLun));
> +
> +    initiator_name = parse_initiator_name(iscsi_url->target);
> +
> +    iscsi = iscsi_create_context(initiator_name);
> +    if (iscsi == NULL) {
> +        error_report("iSCSI: Failed to create iSCSI context.");
> +        ret = -ENOMEM;
> +        goto failed;
> +    }
> +
>      if (iscsi_set_targetname(iscsi, iscsi_url->target)) {
>          error_report("iSCSI: Failed to set target name.");
>          ret = -EINVAL;
> @@ -507,6 +612,14 @@ static int iscsi_open(BlockDriverState *bs, const char 
> *filename, int flags)
>              goto failed;
>          }
>      }
> +
> +    /* check if we got CHAP username/password via the options */
> +    if (parse_chap(iscsi, iscsi_url->target) != 0) {
> +        error_report("iSCSI: Failed to set CHAP user/password");
> +        ret = -EINVAL;
> +        goto failed;
> +    }
> +
>      if (iscsi_set_session_type(iscsi, ISCSI_SESSION_NORMAL) != 0) {
>          error_report("iSCSI: Failed to set session type to normal.");
>          ret = -EINVAL;
> @@ -515,6 +628,9 @@ static int iscsi_open(BlockDriverState *bs, const char 
> *filename, 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);
> +
>      task.iscsilun = iscsilun;
>      task.status = 0;
>      task.complete = 0;
> @@ -548,6 +664,9 @@ static int iscsi_open(BlockDriverState *bs, const char 
> *filename, int flags)
>      return 0;
>  
>  failed:
> +    if (initiator_name != NULL) {
> +        g_free(initiator_name);
> +    }

...that you wouldn't leak initiator_name in success case without strdup.

Kevin