Add the "exec" device type.
The parameters given to this type of device will be executed in a shell.
The output of this command is then used as a definition for a device.

That command can be re-interpreted if the related device is not
plugged-in. It allows for a device definition to react to system
changes (e.g. changing PCI bus for a given device).

Signed-off-by: Gaetan Rivet <gaetan.ri...@6wind.com>
Acked-by: Olga Shern <ol...@mellanox.com>
---
 drivers/net/failsafe/failsafe_args.c    | 102 ++++++++++++++++++++++++++++++++
 drivers/net/failsafe/failsafe_ether.c   |   7 +++
 drivers/net/failsafe/failsafe_private.h |   4 ++
 3 files changed, 113 insertions(+)

diff --git a/drivers/net/failsafe/failsafe_args.c 
b/drivers/net/failsafe/failsafe_args.c
index 773b322..839831f 100644
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -112,6 +112,80 @@ parse_device(struct sub_device *sdev, char *args)
        return 0;
 }
 
+static void
+sanitize_cmdline(char *args)
+{
+       size_t len;
+
+       len = strnlen(args, DEVARGS_MAXLEN);
+       args[len - 1] = '\0';
+}
+
+static int
+execute_cmd(struct sub_device *sdev, char *cmdline)
+{
+       FILE *fp;
+       /* store possible newline as well */
+       char output[DEVARGS_MAXLEN + 1];
+       size_t len;
+       int old_err;
+       int ret;
+
+       DEBUG("'%s'", cmdline);
+       if (cmdline == NULL &&
+           sdev->cmdline == NULL) {
+               /* debug: should never happen to a user */
+               DEBUG("Invalid command line");
+               return -EINVAL;
+       }
+       if (sdev->cmdline == NULL) {
+               char *new_str;
+
+               len = strlen(cmdline) + 1;
+               new_str = rte_realloc(sdev->cmdline, len,
+                               RTE_CACHE_LINE_SIZE);
+               if (new_str == NULL) {
+                       ERROR("Command line allocation failed");
+                       return -ENOMEM;
+               }
+               sdev->cmdline = new_str;
+               snprintf(sdev->cmdline, len, "%s", cmdline);
+       } else {
+               if (strcmp(sdev->cmdline, cmdline))
+                       DEBUG("cmd mismatch: '%s' != '%s'",
+                               sdev->cmdline, cmdline);
+               cmdline = sdev->cmdline;
+       }
+       old_err = errno;
+       fp = popen(cmdline, "r");
+       if (fp == NULL) {
+               ret = errno;
+               ERROR("popen: %s", strerror(errno));
+               errno = old_err;
+               return ret;
+       }
+       /* We only read one line */
+       if (fgets(output, sizeof(output) - 1, fp) == NULL) {
+               DEBUG("Could not read command output");
+               return -ENODEV;
+       }
+       sanitize_cmdline(output);
+       ret = parse_device(sdev, output);
+       if (ret) {
+               ERROR("Parsing device '%s' failed", output);
+               goto ret_pclose;
+       }
+ret_pclose:
+       ret = pclose(fp);
+       if (ret) {
+               ret = errno;
+               ERROR("pclose: %s", strerror(errno));
+               errno = old_err;
+               return ret;
+       }
+       return ret;
+}
+
 static int
 parse_device_param(struct rte_eth_dev *dev, const char *param,
                uint8_t head)
@@ -146,6 +220,14 @@ parse_device_param(struct rte_eth_dev *dev, const char 
*param,
                ret = parse_device(sdev, args);
                if (ret)
                        goto free_args;
+       } else if (strncmp(param, "exec", 4) == 0) {
+               ret = execute_cmd(sdev, args);
+               if (ret == -ENODEV) {
+                       DEBUG("Reading device info from command line failed");
+                       ret = 0;
+               }
+               if (ret)
+                       goto free_args;
        } else {
                ERROR("Unrecognized device type: %.*s", (int)b, param);
                return -EINVAL;
@@ -347,6 +429,8 @@ failsafe_args_free(struct rte_eth_dev *dev)
        uint8_t i;
 
        FOREACH_SUBDEV(sdev, i, dev) {
+               rte_free(sdev->cmdline);
+               sdev->cmdline = NULL;
                free(sdev->devargs.args);
                sdev->devargs.args = NULL;
        }
@@ -377,3 +461,21 @@ failsafe_args_count_subdevice(struct rte_eth_dev *dev,
        return parse_sub_devices(count_device,
                                dev, params);
 }
+
+int
+failsafe_args_parse_subs(struct rte_eth_dev *dev)
+{
+       struct sub_device *sdev;
+       uint8_t i;
+       int ret = 0;
+
+       FOREACH_SUBDEV(sdev, i, dev) {
+               if (sdev->state >= DEV_PARSED)
+                       continue;
+               if (sdev->cmdline)
+                       ret = execute_cmd(sdev, sdev->cmdline);
+               if (ret == 0)
+                       sdev->state = DEV_PARSED;
+       }
+       return 0;
+}
diff --git a/drivers/net/failsafe/failsafe_ether.c 
b/drivers/net/failsafe/failsafe_ether.c
index 9f4a0a0..2d90bcb 100644
--- a/drivers/net/failsafe/failsafe_ether.c
+++ b/drivers/net/failsafe/failsafe_ether.c
@@ -188,6 +188,13 @@ failsafe_eth_dev_state_sync(struct rte_eth_dev *dev)
        int ret;
        uint8_t i;
 
+       if (PRIV(dev)->state < DEV_PARSED)
+               return 0;
+
+       ret = failsafe_args_parse_subs(dev);
+       if (ret)
+               return ret;
+
        if (PRIV(dev)->state < DEV_PROBED)
                return 0;
        ret = failsafe_eal_init(dev);
diff --git a/drivers/net/failsafe/failsafe_private.h 
b/drivers/net/failsafe/failsafe_private.h
index 8659c6f..c1aa24d 100644
--- a/drivers/net/failsafe/failsafe_private.h
+++ b/drivers/net/failsafe/failsafe_private.h
@@ -94,6 +94,9 @@ struct sub_device {
        struct rte_eth_dev_data data;
        /* Device state machine */
        enum dev_state state;
+
+       /* Some device are defined as a command line */
+       char *cmdline;
 };
 
 struct fs_priv {
@@ -140,6 +143,7 @@ uint16_t failsafe_tx_burst(void *txq,
 int failsafe_args_parse(struct rte_eth_dev *dev, const char *params);
 void failsafe_args_free(struct rte_eth_dev *dev);
 int failsafe_args_count_subdevice(struct rte_eth_dev *dev, const char *params);
+int failsafe_args_parse_subs(struct rte_eth_dev *dev);
 
 /* EAL */
 
-- 
2.1.4

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