Re: [dpdk-dev] [RFC 2/2] nfp: allow for non-root user

[Aaron Conole <aconole@redhat.com>]

Alejandro Lucero <alejandro.lucero@netronome.com> writes:

> Again, this patch is correct, but because NFP PMD needs to access
> /sys/bus/pci/devices/$DEVICE_PCI_STRING/resource$RESOURCE_ID, and these files have just
> read/write accesses for root, I do not know if this is really necessary.
>
> Being honest, I have not used a DPDK app with NFP PMD and not being root. Does it work
> with non-root users and other PMDs with same requirements regarding sysfs resource files?

We do run as non-root user definitely with Intel PMDs.

I'm not very sure about other vendors, but I think mlx pmd runs as
non-root user (and it was modified to move off of sysfs for that
reason[1]).

I'll continue to push for more information from the testing side to find
out though.

[1]: http://dpdk.org/ml/archives/dev/2018-February/090586.html

> On Fri, Apr 13, 2018 at 12:22 AM, Aaron Conole <aconole@redhat.com> wrote:
>
>  Currently, the nfp lock files are taken from the global lock file
>  location, which will work when the user is running as root.  However,
>  some distributions and applications (notably ovs 2.8+ on RHEL/Fedora)
>  run as a non-root user.
>
>  Signed-off-by: Aaron Conole <aconole@redhat.com>
>  ---
>   drivers/net/nfp/nfp_nfpu.c | 23 ++++++++++++++++++-----
>   1 file changed, 18 insertions(+), 5 deletions(-)
>
>  diff --git a/drivers/net/nfp/nfp_nfpu.c b/drivers/net/nfp/nfp_nfpu.c
>  index 2ed985ff4..ae2e07220 100644
>  --- a/drivers/net/nfp/nfp_nfpu.c
>  +++ b/drivers/net/nfp/nfp_nfpu.c
>  @@ -18,6 +18,22 @@
>   #define NFP_CFG_EXP_BAR         7
>
>   #define NFP_CFG_EXP_BAR_CFG_BASE       0x30000
>  +#define NFP_LOCKFILE_PATH_FMT "%s/nfp%d"
>  +
>  +/* get nfp lock file path (/var/lock if root, $HOME otherwise) */
>  +static void
>  +nspu_get_lockfile_path(char *buffer, int bufsz, nfpu_desc_t *desc)
>  +{
>  +       const char *dir = "/var/lock";
>  +       const char *home_dir = getenv("HOME");
>  +
>  +       if (getuid() != 0 && home_dir != NULL)
>  +               dir = home_dir;
>  +
>  +       /* use current prefix as file path */
>  +       snprintf(buffer, bufsz, NFP_LOCKFILE_PATH_FMT, dir,
>  +                       desc->nfp);
>  +}
>
>   /* There could be other NFP userspace tools using the NSP interface.
>    * Make sure there is no other process using it and locking the access for
>  @@ -30,9 +46,7 @@ nspv_aquire_process_lock(nfpu_desc_t *desc)
>          struct flock lock;
>          char lockname[30];
>
>  -       memset(&lock, 0, sizeof(lock));
>  -
>  -       snprintf(lockname, sizeof(lockname), "/var/lock/nfp%d", desc->nfp);
>  +       nspu_get_lockfile_path(lockname, sizeof(lockname), desc);
>
>          /* Using S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH */
>          desc->lock = open(lockname, O_RDWR | O_CREAT, 0666);
>  @@ -106,7 +120,6 @@ nfpu_close(nfpu_desc_t *desc)
>          rte_free(desc->nspu);
>          close(desc->lock);
>
>  -       snprintf(lockname, sizeof(lockname), "/var/lock/nfp%d", desc->nfp);
>  -       unlink(lockname);
>  +       nspu_get_lockfile_path(lockname, sizeof(lockname), desc);
>          return 0;
>   }
>  -- 
>  2.14.3