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

[Alejandro Lucero]

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?



On Fri, Apr 13, 2018 at 12:22 AM, Aaron Conole <aconole at 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 at 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
>
>