Re: [PATCH 3/4] Use systemd-generated hostid if no hostid is configured

[David Milburn <dmilburn@redhat.com>]

Hello Andy,

On 12/19/2019 09:31 PM, Andy Lutomirski wrote:
> This is just like the hostnqn support.  It adds a show-hostid command
> for introspection.
> 
> Signed-off-by: Andy Lutomirski <luto@kernel.org>
> ---
>   Documentation/nvme-show-hostid.txt | 29 +++++++++++++++
>   fabrics.c                          | 57 ++++++++++++++++++++++++++----
>   fabrics.h                          |  1 +
>   nvme-builtin.h                     |  1 +
>   nvme.c                             | 15 ++++++++
>   5 files changed, 96 insertions(+), 7 deletions(-)
>   create mode 100644 Documentation/nvme-show-hostid.txt
> 
> diff --git a/Documentation/nvme-show-hostid.txt b/Documentation/nvme-show-hostid.txt
> new file mode 100644
> index 000000000000..52bdc8a1f480
> --- /dev/null
> +++ b/Documentation/nvme-show-hostid.txt
> @@ -0,0 +1,29 @@
> +nvme-show-hostid(1)
> +===================
> +
> +NAME
> +----
> +nvme-show-hostid - Generate a host NVMe ID
> +

I pulled the latest nvme-cli and applied your patch set

https://github.com/linux-nvme/nvme-cli

Seems to work on Fedora 31

$ nvme show-hostnqn
nqn.2019-10.us.luto:sd_id128_app:a9e4b2c8953340988142e32ca6d67922

$ nvme show-hostid
f467779d-1940-4659-b200-74278899b2ca

Thanks,
David


> +SYNOPSIS
> +--------
> +[verse]
> +'nvme show-hostid'
> +
> +DESCRIPTION
> +-----------
> +Show the host ID configured for the system.  If /etc/nvme/hostid is
> +not present and systemd application-specific machine IDs are available,
> +this will show the systemd-generated host ID for the system.
> +
> +OPTIONS
> +-------
> +No options needed
> +
> +EXAMPLES
> +--------
> +nvme show-hostid
> +
> +NVME
> +----
> +Part of the nvme-user suite
> diff --git a/fabrics.c b/fabrics.c
> index 4448416f9855..7c5b7efd5270 100644
> --- a/fabrics.c
> +++ b/fabrics.c
> @@ -46,6 +46,7 @@
>   #ifdef HAVE_SYSTEMD
>   #include <systemd/sd-id128.h>
>   #define NVME_HOSTNQN_ID SD_ID128_MAKE(c7,f4,61,81,12,be,49,32,8c,83,10,6f,9d,dd,d8,6b)
> +#define NVME_HOSTID_ID SD_ID128_MAKE(df,66,bf,ec,f7,e4,21,0e,46,27,ac,a8,f2,8f,3b,98)
>   #endif
>   
>   #define NVMF_HOSTID_SIZE	36
> @@ -728,11 +729,11 @@ static int nvmf_hostnqn_load(void)
>   	return cfg.hostnqn != NULL;
>   }
>   
> -static int nvmf_hostid_file(void)
> +static char *hostid_read_file(void)
>   {
>   	FILE *f;
>   	char hostid[NVMF_HOSTID_SIZE + 1];
> -	int ret = false;
> +	char *ret = NULL;
>   
>   	f = fopen(PATH_NVMF_HOSTID, "r");
>   	if (f == NULL)
> @@ -741,16 +742,58 @@ static int nvmf_hostid_file(void)
>   	if (fgets(hostid, sizeof(hostid), f) == NULL)
>   		goto out;
>   
> -	cfg.hostid = strdup(hostid);
> -	if (!cfg.hostid)
> -		goto out;
> +	ret = strdup(hostid);
> +
>   
> -	ret = true;
>   out:
>   	fclose(f);
>   	return ret;
>   }
>   
> +static char *hostid_generate_systemd(void)
> +{
> +#if defined(LIBUUID) && defined(HAVE_SYSTEMD)
> +	sd_id128_t id;
> +	char uuidstr[37];
> +	char *ret;
> +
> +	if (sd_id128_get_machine_app_specific(NVME_HOSTID_ID, &id) < 0)
> +		return NULL;
> +
> +	uuid_unparse_lower(id.bytes, uuidstr);
> +
> +	if (asprintf(&ret, "%s\n", uuidstr) == -1)
> +		ret = NULL;
> +
> +	return ret;
> +#else
> +	return NULL;
> +#endif
> +}
> +
> +/* returns an allocated string or NULL */
> +char *hostid_read(void)
> +{
> +	char *ret;
> +
> +	ret = hostid_read_file();
> +	if (ret)
> +		return ret;
> +
> +	ret = hostid_generate_systemd();
> +	if (ret)
> +		return ret;
> +
> +	return NULL;
> +}
> +
> +static int nvmf_hostid_load(void)
> +{
> +	cfg.hostid = hostid_read();
> +
> +	return cfg.hostid != NULL;
> +}
> +
>   static int
>   add_bool_argument(char **argstr, int *max_len, char *arg_str, bool arg)
>   {
> @@ -829,7 +872,7 @@ static int build_options(char *argstr, int max_len, bool discover)
>   	    add_argument(&argstr, &max_len, "trsvcid", cfg.trsvcid) ||
>   	    ((cfg.hostnqn || nvmf_hostnqn_load()) &&
>   		    add_argument(&argstr, &max_len, "hostnqn", cfg.hostnqn)) ||
> -	    ((cfg.hostid || nvmf_hostid_file()) &&
> +	    ((cfg.hostid || nvmf_hostid_load()) &&
>   		    add_argument(&argstr, &max_len, "hostid", cfg.hostid)) ||
>   	    (!discover &&
>   	      add_int_argument(&argstr, &max_len, "nr_io_queues",
> diff --git a/fabrics.h b/fabrics.h
> index b8e53f492b53..64aede897535 100644
> --- a/fabrics.h
> +++ b/fabrics.h
> @@ -4,6 +4,7 @@
>   #define NVMF_DEF_DISC_TMO	30
>   
>   extern char *hostnqn_read(void);
> +extern char *hostid_read(void);
>   
>   extern int discover(const char *desc, int argc, char **argv, bool connect);
>   extern int connect(const char *desc, int argc, char **argv);
> diff --git a/nvme-builtin.h b/nvme-builtin.h
> index bfb907dff9ef..907d470cbeac 100644
> --- a/nvme-builtin.h
> +++ b/nvme-builtin.h
> @@ -71,6 +71,7 @@ COMMAND_LIST(
>   	ENTRY("disconnect-all", "Disconnect from all connected NVMeoF subsystems", disconnect_all_cmd)
>   	ENTRY("gen-hostnqn", "Generate NVMeoF host NQN", gen_hostnqn_cmd)
>   	ENTRY("show-hostnqn", "Show NVMeoF host NQN", show_hostnqn_cmd)
> +	ENTRY("show-hostid", "Show NVMeoF host ID", show_hostid_cmd)
>   	ENTRY("dir-receive", "Submit a Directive Receive command, return results", dir_receive)
>   	ENTRY("dir-send", "Submit a Directive Send command, return results", dir_send)
>   	ENTRY("virt-mgmt", "Manage Flexible Resources between Primary and Secondary Controller ", virtual_mgmt)
> diff --git a/nvme.c b/nvme.c
> index 0c23eee8a477..d81f8226b84d 100644
> --- a/nvme.c
> +++ b/nvme.c
> @@ -4771,6 +4771,21 @@ static int show_hostnqn_cmd(int argc, char **argv, struct command *command, stru
>   	}
>   }
>   
> +static int show_hostid_cmd(int argc, char **argv, struct command *command, struct plugin *plugin)
> +{
> +	char *hostid;
> +
> +	hostid = hostid_read();
> +	if (hostid) {
> +		fputs(hostid, stdout);
> +		free(hostid);
> +		return 0;
> +	} else {
> +		fprintf(stderr, "hostid is not available -- generate /etc/nvme/hostid\n");
> +		return -ENOENT;
> +	}
> +}
> +
>   static int discover_cmd(int argc, char **argv, struct command *command, struct plugin *plugin)
>   {
>   	const char *desc = "Send Get Log Page request to Discovery Controller.";
> 


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