[PATCH nvme-cli v1 1/2] nvme-cli: Add nvme hostnqn generation option

[J Freyensee]

On Tue, 2016-11-08 at 12:48 +0200, Sagi Grimberg wrote:
> Add option to generate a NVMe qualified name of a given host
> (in the form of: nqn.2014-08.org.nvmexpress:NVMf:uuid:<some_uuid>).
> This hostnqn will be used for fabrics discovery and connect
> functions.
> 
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
> ---
>  Makefile       |  1 +
>  nvme-builtin.h |  1 +
>  nvme.c         | 14 ++++++++++++++
>  3 files changed, 16 insertions(+)
> 
> diff --git a/Makefile b/Makefile
> index 117cbbea886f..cc0245ad576d 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1,5 +1,6 @@
>  CFLAGS += -std=gnu99 -O2 -g -Wall -Werror
>  CPPFLAGS += -D_GNU_SOURCE -D__CHECK_ENDIAN__
> +LDFLAGS += -luuid
>  NVME = nvme
>  INSTALL ?= install
>  DESTDIR =
> diff --git a/nvme-builtin.h b/nvme-builtin.h
> index dc314cbbb371..b182b1e01f5b 100644
> --- a/nvme-builtin.h
> +++ b/nvme-builtin.h
> @@ -49,6 +49,7 @@ COMMAND_LIST(
>  	ENTRY("connect-all", "Discover and Connect to NVMeoF
> subsystems", connect_all_cmd)
>  	ENTRY("connect", "Connect to NVMeoF subsystem", connect_cmd)
>  	ENTRY("disconnect", "Disconnect from NVMeoF subsystem",
> disconnect_cmd)
> +	ENTRY("gen-hostnqn", "Generate NVMeoF host NQN",
> gen_hostnqn_cmd)
>  );
>  
>  #endif
> diff --git a/nvme.c b/nvme.c
> index a9e78aae50a9..fa9765cddc79 100644
> --- a/nvme.c
> +++ b/nvme.c
> @@ -44,6 +44,7 @@
>  #include <sys/types.h>
>  #include <sys/stat.h>
>  #include <sys/time.h>
> +#include <uuid/uuid.h>
>  
>  #include "nvme-print.h"
>  #include "nvme-ioctl.h"
> @@ -2704,6 +2705,19 @@ static int admin_passthru(int argc, char
> **argv, struct command *cmd, struct plu
>  	return passthru(argc, argv, NVME_IOCTL_ADMIN_CMD, desc,
> cmd);
>  }
>  
> +static int gen_hostnqn_cmd(int argc, char **argv, struct command
> *command, struct plugin *plugin)
> +{
> +	char hostnqn[NVMF_NQN_SIZE];
> +	uuid_t uuid;
> +	char uuid_str[37]; /* e.g. 1b4e28ba-2fa1-11d2-883f-
> 0016d3cca427 + \0 */
> +
> +	uuid_generate_random(uuid);
> +	uuid_unparse_lower(uuid, uuid_str);
> +	sprintf(hostnqn, "nqn.2014-08.org.nvmexpress:NVMf:uuid:%s",
> uuid_str);

Let's do what the driver does, use a snprintf() and limit the size via
NVMF_NQN_SIZE used by hostnqn[].