[PATCH v5 07/10] devargs: make parsing variadic

[Gaetan Rivet <gaetan.rivet@6wind.com>]

rte_eal_devargs_parse can be used by EAL subsystems, drivers,
applications alike.

Device parameters may be presented with different structure each time;
as a single declaration string or several strings each describing
different parts of the declaration.

To simplify the use of this parsing facility, its parameters are made
variadic.

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
---
 drivers/net/failsafe/failsafe_args.c        |  2 +-
 drivers/net/failsafe/failsafe_eal.c         |  2 +-
 lib/librte_eal/common/eal_common_dev.c      | 33 ++++-------------------------
 lib/librte_eal/common/eal_common_devargs.c  | 15 ++++++++++---
 lib/librte_eal/common/include/rte_devargs.h | 11 ++++++----
 5 files changed, 25 insertions(+), 38 deletions(-)

diff --git a/drivers/net/failsafe/failsafe_args.c b/drivers/net/failsafe/failsafe_args.c
index 20d2f520a..5edc061e8 100644
--- a/drivers/net/failsafe/failsafe_args.c
+++ b/drivers/net/failsafe/failsafe_args.c
@@ -63,7 +63,7 @@ fs_parse_device(struct sub_device *sdev, char *args)
 
 	d = &sdev->devargs;
 	DEBUG("%s", args);
-	ret = rte_eal_devargs_parse(args, d);
+	ret = rte_eal_devargs_parse(d, "%s", args);
 	if (ret) {
 		DEBUG("devargs parsing failed with code %d", ret);
 		return ret;
diff --git a/drivers/net/failsafe/failsafe_eal.c b/drivers/net/failsafe/failsafe_eal.c
index 4078fdbb0..c11621e93 100644
--- a/drivers/net/failsafe/failsafe_eal.c
+++ b/drivers/net/failsafe/failsafe_eal.c
@@ -69,7 +69,7 @@ fs_bus_init(struct rte_eth_dev *dev)
 			else
 				snprintf(devstr, sizeof(devstr), "%s",
 					 rte_eth_devices[pid].device->name);
-			ret = rte_eal_devargs_parse(devstr, da);
+			ret = rte_eal_devargs_parse(da, "%s", devstr);
 			if (ret) {
 				ERROR("Probed devargs parsing failed with code"
 				      " %d", ret);
diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
index 149e9ad72..809d6649d 100644
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -114,29 +114,12 @@ int rte_eal_dev_detach(struct rte_device *dev)
 	return ret;
 }
 
-static char *
-full_dev_name(const char *bus, const char *dev, const char *args)
-{
-	char *name;
-	size_t len;
-
-	len = snprintf(NULL, 0, "%s:%s,%s", bus, dev, args) + 1;
-	name = calloc(1, len);
-	if (name == NULL) {
-		RTE_LOG(ERR, EAL, "Could not allocate full device name\n");
-		return NULL;
-	}
-	snprintf(name, len, "%s:%s,%s", bus, dev, args);
-	return name;
-}
-
 int __rte_experimental rte_eal_hotplug_add(const char *busname, const char *devname,
 			const char *devargs)
 {
 	struct rte_bus *bus;
 	struct rte_device *dev;
 	struct rte_devargs *da;
-	char *name;
 	int ret;
 
 	bus = rte_bus_find_by_name(busname);
@@ -151,17 +134,12 @@ int __rte_experimental rte_eal_hotplug_add(const char *busname, const char *devn
 		return -ENOTSUP;
 	}
 
-	name = full_dev_name(busname, devname, devargs);
-	if (name == NULL)
+	da = calloc(1, sizeof(*da));
+	if (da == NULL)
 		return -ENOMEM;
 
-	da = calloc(1, sizeof(*da));
-	if (da == NULL) {
-		ret = -ENOMEM;
-		goto err_name;
-	}
-
-	ret = rte_eal_devargs_parse(name, da);
+	ret = rte_eal_devargs_parse(da, "%s:%s,%s",
+				    busname, devname, devargs);
 	if (ret)
 		goto err_devarg;
 
@@ -187,7 +165,6 @@ int __rte_experimental rte_eal_hotplug_add(const char *busname, const char *devn
 			dev->name);
 		goto err_devarg;
 	}
-	free(name);
 	return 0;
 
 err_devarg:
@@ -195,8 +172,6 @@ int __rte_experimental rte_eal_hotplug_add(const char *busname, const char *devn
 		free(da->args);
 		free(da);
 	}
-err_name:
-	free(name);
 	return ret;
 }
 
diff --git a/lib/librte_eal/common/eal_common_devargs.c b/lib/librte_eal/common/eal_common_devargs.c
index a7f374cfa..b251bb0a6 100644
--- a/lib/librte_eal/common/eal_common_devargs.c
+++ b/lib/librte_eal/common/eal_common_devargs.c
@@ -11,6 +11,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <stdarg.h>
 
 #include <rte_compat.h>
 #include <rte_dev.h>
@@ -62,15 +63,23 @@ bus_name_cmp(const struct rte_bus *bus, const void *name)
 }
 
 int __rte_experimental
-rte_eal_devargs_parse(const char *dev, struct rte_devargs *da)
+rte_eal_devargs_parse(struct rte_devargs *da, const char *format, ...)
 {
 	struct rte_bus *bus = NULL;
+	va_list ap;
+	va_start(ap, format);
+	char dev[vsnprintf(NULL, 0, format, ap) + 1];
 	const char *devname;
 	const size_t maxlen = sizeof(da->name);
 	size_t i;
 
-	if (dev == NULL || da == NULL)
+	va_end(ap);
+	if (da == NULL)
 		return -EINVAL;
+
+	va_start(ap, format);
+	vsnprintf(dev, sizeof(dev), format, ap);
+	va_end(ap);
 	/* Retrieve eventual bus info */
 	do {
 		devname = dev;
@@ -140,7 +149,7 @@ rte_eal_devargs_add(enum rte_devtype devtype, const char *devargs_str)
 	if (devargs == NULL)
 		goto fail;
 
-	if (rte_eal_devargs_parse(dev, devargs))
+	if (rte_eal_devargs_parse(devargs, "%s", dev))
 		goto fail;
 	devargs->type = devtype;
 	bus = devargs->bus;
diff --git a/lib/librte_eal/common/include/rte_devargs.h b/lib/librte_eal/common/include/rte_devargs.h
index e48cc3cf2..eff7a3f8c 100644
--- a/lib/librte_eal/common/include/rte_devargs.h
+++ b/lib/librte_eal/common/include/rte_devargs.h
@@ -94,18 +94,21 @@ int rte_eal_parse_devargs_str(const char *devargs_str,
  * in argument. Store which bus will handle the device, its name
  * and the eventual device parameters.
  *
- * @param dev
- *   The device declaration string.
+ * The device string is built with a printf-like syntax.
+ *
  * @param da
  *   The devargs structure holding the device information.
+ * @param format
+ *   Format string describing a device.
  *
  * @return
  *   - 0 on success.
  *   - Negative errno on error.
  */
 int __rte_experimental
-rte_eal_devargs_parse(const char *dev,
-		      struct rte_devargs *da);
+rte_eal_devargs_parse(struct rte_devargs *da,
+		      const char *format, ...)
+__attribute__((format(printf, 2, 0)));
 
 /**
  * Insert an rte_devargs in the global list.
-- 
2.11.0