[dpdk-dev] [PATCH v6 16/19] devargs: introduce cleaner parsing helper

[Gaetan Rivet]

Introduce a more versatile helper to parse device strings. This
helper expects a generic rte_devargs structure as storage in order not
to require any API changes in the future, should this structure be
updated.

The old equivalent function is thus being deprecated, as its API does
not allow to accompany current rte_devargs evolutions.

A deprecation notice is issued.

This new helper will parse bus information as well as device name and
device parameters. It does not allocate an rte_devargs structure and
expects one to be given as input.

Signed-off-by: Gaetan Rivet <gaetan.rivet at 6wind.com>
---
 doc/guides/rel_notes/deprecation.rst            |  5 ++
 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
 lib/librte_eal/common/eal_common_devargs.c      | 78 ++++++++++++++++---------
 lib/librte_eal/common/include/rte_devargs.h     | 20 +++++++
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
 5 files changed, 79 insertions(+), 26 deletions(-)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 2e708db..56d0698 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -95,3 +95,8 @@ Deprecation Notices
   The non-"do-sig" versions of the hash tables will be removed
   (including the ``signature_offset`` parameter)
   and the "do-sig" versions renamed accordingly.
+
+* eal: the following function is deprecated starting from 17.08 and will
+  be removed in 17.11:
+
+  - ``rte_eal_parse_devargs_str``, replaced by ``rte_eal_devargs_parse``
diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 0295ea9..cec3894 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -200,6 +200,7 @@ DPDK_17.08 {
 	rte_bus_find;
 	rte_bus_find_by_device;
 	rte_bus_find_by_name;
+	rte_eal_devargs_parse;
 
 } DPDK_17.05;
 
diff --git a/lib/librte_eal/common/eal_common_devargs.c b/lib/librte_eal/common/eal_common_devargs.c
index 8fe1b39..3ea070d 100644
--- a/lib/librte_eal/common/eal_common_devargs.c
+++ b/lib/librte_eal/common/eal_common_devargs.c
@@ -86,49 +86,77 @@ bus_name_cmp(const struct rte_bus *bus, const void *_name)
 		       strlen(bus->name));
 }
 
-/* store a whitelist parameter for later parsing */
 int
-rte_eal_devargs_add(enum rte_devtype devtype, const char *devargs_str)
+rte_eal_devargs_parse(const char *dev, struct rte_devargs *da)
 {
-	struct rte_devargs *devargs = NULL;
 	struct rte_bus *bus = NULL;
-	char *dev = NULL;
 	const char *devname;
-	int ret;
-
-	/* use malloc instead of rte_malloc as it's called early at init */
-	devargs = malloc(sizeof(*devargs));
-	if (devargs == NULL)
-		goto fail;
-
-	memset(devargs, 0, sizeof(*devargs));
-	devargs->type = devtype;
+	const size_t maxlen = sizeof(da->name);
+	size_t i;
 
-	if (rte_eal_parse_devargs_str(devargs_str, &dev, &devargs->args))
-		goto fail;
-	devname = dev;
+	if (dev == NULL || da == NULL)
+		return -EINVAL;
+	/* Retrieve eventual bus info */
 	do {
+		devname = dev;
 		bus = rte_bus_find(bus, bus_name_cmp, dev);
 		if (bus == NULL)
 			break;
 		devname = dev + strlen(bus->name) + 1;
 		if (rte_bus_find_by_device_name(devname) == bus)
 			break;
-		devname = dev;
 	} while (1);
+	/* Store device name */
+	i = 0;
+	while (devname[i] != '\0' && devname[i] != ',') {
+		da->name[i] = devname[i];
+		i++;
+		if (i == maxlen) {
+			fprintf(stderr, "WARNING: Parsing \"%s\": device name should be shorter than %zu\n",
+				dev, maxlen);
+			da->name[i - 1] = '\0';
+			return -EINVAL;
+		}
+	}
+	da->name[i] = '\0';
 	if (bus == NULL) {
-		bus = rte_bus_find_by_device_name(devname);
+		bus = rte_bus_find_by_device_name(da->name);
 		if (bus == NULL) {
-			fprintf(stderr, "ERROR: failed to parse bus info from device declaration\n");
-			goto fail;
+			fprintf(stderr, "ERROR: failed to parse device \"%s\"\n",
+				da->name);
+			return -EFAULT;
 		}
 	}
-	devargs->bus = bus;
+	da->bus = bus;
+	/* Parse eventual device arguments */
+	if (devname[i] == ',')
+		da->args = strdup(&devname[i + 1]);
+	else
+		da->args = strdup("");
+	if (da->args == NULL) {
+		fprintf(stderr, "ERROR: not enough memory to parse arguments\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+/* store a whitelist parameter for later parsing */
+int
+rte_eal_devargs_add(enum rte_devtype devtype, const char *devargs_str)
+{
+	struct rte_devargs *devargs = NULL;
+	struct rte_bus *bus = NULL;
+	const char *dev = devargs_str;
 
-	/* save device name. */
-	ret = snprintf(devargs->name, sizeof(devargs->name), "%s", devname);
-	if (ret < 0 || ret >= (int)sizeof(devargs->name))
+	/* use calloc instead of rte_zmalloc as it's called early at init */
+	devargs = calloc(1, sizeof(*devargs));
+	if (devargs == NULL)
 		goto fail;
+
+	if (rte_eal_devargs_parse(dev, devargs))
+		goto fail;
+	devargs->type = devtype;
+	bus = devargs->bus;
 	if (devargs->type == RTE_DEVTYPE_WHITELISTED) {
 		if (bus->conf.scan_mode == RTE_BUS_SCAN_UNDEFINED) {
 			bus->conf.scan_mode = RTE_BUS_SCAN_WHITELIST;
@@ -145,12 +173,10 @@ rte_eal_devargs_add(enum rte_devtype devtype, const char *devargs_str)
 		}
 	}
 
-	free(dev);
 	TAILQ_INSERT_TAIL(&devargs_list, devargs, next);
 	return 0;
 
 fail:
-	free(dev);
 	if (devargs) {
 		free(devargs->args);
 		free(devargs);
diff --git a/lib/librte_eal/common/include/rte_devargs.h b/lib/librte_eal/common/include/rte_devargs.h
index 6e9e134..2ab8864 100644
--- a/lib/librte_eal/common/include/rte_devargs.h
+++ b/lib/librte_eal/common/include/rte_devargs.h
@@ -119,6 +119,26 @@ int rte_eal_parse_devargs_str(const char *devargs_str,
 				char **drvname, char **drvargs);
 
 /**
+ * Parse a device string.
+ *
+ * Verify that a bus is capable of handling the device passed
+ * in argument. Store which bus will handle the device, its name
+ * and the eventual device parameters.
+ *
+ * @param dev
+ *   The device declaration string.
+ * @param da
+ *   The devargs structure holding the device information.
+ *
+ * @return
+ *   - 0 on success.
+ *   - Negative errno on error.
+ */
+int
+rte_eal_devargs_parse(const char *dev,
+		      struct rte_devargs *da);
+
+/**
  * Add a device to the user device list
  *
  * For PCI devices, the format of arguments string is "PCI_ADDR" or
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index a118fb1..09b875a 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -205,6 +205,7 @@ DPDK_17.08 {
 	rte_bus_find;
 	rte_bus_find_by_device;
 	rte_bus_find_by_name;
+	rte_eal_devargs_parse;
 
 } DPDK_17.05;
 
-- 
2.1.4