net/failsafe: add fd parameter

This parameter enables applications to provide device definitions
through an arbitrary file descriptor number.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>
Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>

diff --git a/doc/guides/nics/fail_safe.rst b/doc/guides/nics/fail_safe.rst
index c4e3d2e..5b1b47e 100644 (file)
--- a/doc/guides/nics/fail_safe.rst
+++ b/doc/guides/nics/fail_safe.rst
@@ -106,6 +106,15 @@ Fail-safe command line parameters
   All commas within the ``shell command`` are replaced by spaces before
   executing the command. This helps using scripts to specify devices.
 
+- **fd(<file descriptor number>)** parameter
+
+  This parameter reads a device definition from an arbitrary file descriptor
+  number in ``<iface>`` format as described above.
+
+  The file descriptor is read in non-blocking mode and is never closed in
+  order to take only the last line into account (unlike ``exec()``) at every
+  probe attempt.
+
 - **mac** parameter [MAC address]
 
   This parameter allows the user to set a default MAC address to the fail-safe

diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
index ec63ac9..a1fb3fa 100644 (file)
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -31,7 +31,11 @@
  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 #include <errno.h>
 
 #include <rte_debug.h>
@@ -160,6 +164,67 @@ ret_pclose:
        return ret;
 }
 
+static int
+fs_read_fd(struct sub_device *sdev, char *fd_str)
+{
+       FILE *fp = NULL;
+       int fd = -1;
+       /* store possible newline as well */
+       char output[DEVARGS_MAXLEN + 1];
+       int err = -ENODEV;
+       int oflags;
+       int lcount;
+
+       RTE_ASSERT(fd_str != NULL || sdev->fd_str != NULL);
+       if (sdev->fd_str == NULL) {
+               sdev->fd_str = strdup(fd_str);
+               if (sdev->fd_str == NULL) {
+                       ERROR("Command line allocation failed");
+                       return -ENOMEM;
+               }
+       }
+       errno = 0;
+       fd = strtol(fd_str, &fd_str, 0);
+       if (errno || *fd_str || fd < 0) {
+               ERROR("Parsing FD number failed");
+               goto error;
+       }
+       /* Fiddle with copy of file descriptor */
+       fd = dup(fd);
+       if (fd == -1)
+               goto error;
+       oflags = fcntl(fd, F_GETFL);
+       if (oflags == -1)
+               goto error;
+       if (fcntl(fd, F_SETFL, oflags | O_NONBLOCK) == -1)
+               goto error;
+       fp = fdopen(fd, "r");
+       if (fp == NULL)
+               goto error;
+       fd = -1;
+       /* Only take the last line into account */
+       lcount = 0;
+       while (fgets(output, sizeof(output), fp))
+               ++lcount;
+       if (lcount == 0)
+               goto error;
+       else if (ferror(fp) && errno != EAGAIN)
+               goto error;
+       /* Line must end with a newline character */
+       fs_sanitize_cmdline(output);
+       if (output[0] == '\0')
+               goto error;
+       err = fs_parse_device(sdev, output);
+       if (err)
+               ERROR("Parsing device '%s' failed", output);
+error:
+       if (fp)
+               fclose(fp);
+       if (fd != -1)
+               close(fd);
+       return err;
+}
+
 static int
 fs_parse_device_param(struct rte_eth_dev *dev, const char *param,
                uint8_t head)
@@ -202,6 +267,14 @@ fs_parse_device_param(struct rte_eth_dev *dev, const char *param,
                }
                if (ret)
                        goto free_args;
+       } else if (strncmp(param, "fd(", 3) == 0) {
+               ret = fs_read_fd(sdev, args);
+               if (ret == -ENODEV) {
+                       DEBUG("Reading device info from FD failed");
+                       ret = 0;
+               }
+               if (ret)
+                       goto free_args;
        } else {
                ERROR("Unrecognized device type: %.*s", (int)b, param);
                return -EINVAL;
@@ -409,6 +482,8 @@ failsafe_args_free(struct rte_eth_dev *dev)
        FOREACH_SUBDEV(sdev, i, dev) {
                free(sdev->cmdline);
                sdev->cmdline = NULL;
+               free(sdev->fd_str);
+               sdev->fd_str = NULL;
                free(sdev->devargs.args);
                sdev->devargs.args = NULL;
        }
@@ -424,7 +499,8 @@ fs_count_device(struct rte_eth_dev *dev, const char *param,
                param[b] != '\0')
                b++;
        if (strncmp(param, "dev", b) != 0 &&
-           strncmp(param, "exec", b) != 0) {
+           strncmp(param, "exec", b) != 0 &&
+           strncmp(param, "fd(", b) != 0) {
                ERROR("Unrecognized device type: %.*s", (int)b, param);
                return -EINVAL;
        }
@@ -463,6 +539,8 @@ failsafe_args_parse_subs(struct rte_eth_dev *dev)
                        continue;
                if (sdev->cmdline)
                        ret = fs_execute_cmd(sdev, sdev->cmdline);
+               else if (sdev->fd_str)
+                       ret = fs_read_fd(sdev, sdev->fd_str);
                else
                        ret = fs_parse_sub_device(sdev);
                if (ret == 0)

diff --git a/drivers/net/failsafe/failsafe_private.h b/drivers/net/failsafe/failsafe_private.h
index 54b5b91..5e04ffe 100644 (file)
--- a/drivers/net/failsafe/failsafe_private.h
+++ b/drivers/net/failsafe/failsafe_private.h
@@ -48,6 +48,7 @@
 #define PMD_FAILSAFE_PARAM_STRING      \
        "dev(<ifc>),"                   \
        "exec(<shell command>),"        \
+       "fd(<fd number>),"              \
        "mac=mac_addr,"                 \
        "hotplug_poll=u64"              \
        ""
@@ -112,6 +113,8 @@ struct sub_device {
        struct fs_stats stats_snapshot;
        /* Some device are defined as a command line */
        char *cmdline;
+       /* Others are retrieved through a file descriptor */
+       char *fd_str;
        /* fail-safe device backreference */
        struct rte_eth_dev *fs_dev;
        /* flag calling for recollection */