eal: support driver loading from directory

Add support for directories as arguments to -d for loading all drivers
from a given directory. Additionally a default driver directory can be
set in build-time configuration, in which case it will be always be used
when EAL is initialized.

This simplifies usage in shared library configuration significantly over
manually loading individual drivers with -d, and allows distros to
establish a drop-in driver directory for seamless integration
with 3rd party drivers etc.

Suggested-by: Thomas Monjalon <thomas.monjalon@6wind.com>
Suggested-by: David Marchand <david.marchand@6wind.com>
Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
Acked-by: David Marchand <david.marchand@6wind.com>

config/common_bsdapp

@@ -108,6 +108,9 @@ CONFIG_RTE_EAL_ALLOW_INV_SOCKET_ID=n
 CONFIG_RTE_EAL_ALWAYS_PANIC_ON_ERROR=n
 CONFIG_RTE_MALLOC_DEBUG=n
 
+# Default driver path (or "" to disable)
+CONFIG_RTE_EAL_PMD_PATH=""
+
 #
 # FreeBSD contiguous memory driver settings
 #

config/common_linuxapp

@@ -111,6 +111,9 @@ CONFIG_RTE_EAL_IGB_UIO=y
 CONFIG_RTE_EAL_VFIO=y
 CONFIG_RTE_MALLOC_DEBUG=n
 
+# Default driver path (or "" to disable)
+CONFIG_RTE_EAL_PMD_PATH=""
+
 #
 # Special configurations in PCI Config Space for high performance
 #

lib/librte_eal/common/eal_common_options.c

@@ -40,6 +40,9 @@
 #include <errno.h>
 #include <getopt.h>
 #include <dlfcn.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
 
 #include <rte_eal.h>
 #include <rte_log.h>
@@ -109,6 +112,9 @@ struct shared_driver {
 static struct shared_driver_list solib_list =
 TAILQ_HEAD_INITIALIZER(solib_list);
 
+/* Default path of external loadable drivers */
+static const char *default_solib_dir = RTE_EAL_PMD_PATH;
+
 static int master_lcore_parsed;
 static int mem_parsed;
 
@@ -167,18 +173,75 @@ eal_plugin_add(const char *path)
 	return 0;
 }
 
+static int
+eal_plugindir_init(const char *path)
+{
+	DIR *d = NULL;
+	struct dirent *dent = NULL;
+	char sopath[PATH_MAX];
+
+	if (path == NULL || *path == '\0')
+		return 0;
+
+	d = opendir(path);
+	if (d == NULL) {
+		RTE_LOG(ERR, EAL, "failed to open directory %s: %s\n",
+			path, strerror(errno));
+		return -1;
+	}
+
+	while ((dent = readdir(d)) != NULL) {
+		if (dent->d_type != DT_REG && dent->d_type != DT_LNK)
+			continue;
+
+		snprintf(sopath, PATH_MAX-1, "%s/%s", path, dent->d_name);
+		sopath[PATH_MAX-1] = 0;
+
+		if (eal_plugin_add(sopath) == -1)
+			break;
+	}
+
+	closedir(d);
+	/* XXX this ignores failures from readdir() itself */
+	return (dent == NULL) ? 0 : -1;
+}
+
 int
 eal_plugins_init(void)
 {
 	struct shared_driver *solib = NULL;
 
+	if (*default_solib_dir != '\0')
+		eal_plugin_add(default_solib_dir);
+
 	TAILQ_FOREACH(solib, &solib_list, next) {
-		RTE_LOG(DEBUG, EAL, "open shared lib %s\n", solib->name);
+		struct stat sb;
-		solib->lib_handle = dlopen(solib->name, RTLD_NOW);
+		if (stat(solib->name, &sb) == -1) {
-		if (solib->lib_handle == NULL) {
+			RTE_LOG(ERR, EAL, "Invalid plugin specified: %s: %s\n",
-			RTE_LOG(ERR, EAL, "%s\n", dlerror());
+				solib->name, strerror(errno));
 			return -1;
 		}
+
+		switch (sb.st_mode & S_IFMT) {
+		case S_IFDIR:
+			if (eal_plugindir_init(solib->name) == -1) {
+				RTE_LOG(ERR, EAL,
+					"Cannot init plugin directory %s\n",
+					solib->name);
+				return -1;
+			}
+			break;
+		case S_IFREG:
+			RTE_LOG(DEBUG, EAL, "open shared lib %s\n",
+				solib->name);
+			solib->lib_handle = dlopen(solib->name, RTLD_NOW);
+			if (solib->lib_handle == NULL) {
+				RTE_LOG(ERR, EAL, "%s\n", dlerror());
+				return -1;
+			}
+			break;
+		}
+
 	}
 	return 0;
 }
@@ -948,7 +1011,8 @@ eal_common_usage(void)
 	       "  --"OPT_VDEV"              Add a virtual device.\n"
 	       "                      The argument format is <driver><id>[,key=val,...]\n"
 	       "                      (ex: --vdev=eth_pcap0,iface=eth2).\n"
-	       "  -d LIB.so           Add driver (can be used multiple times)\n"
+	       "  -d LIB.so|DIR       Add a driver or driver directory\n"
+	       "                      (can be used multiple times)\n"
 	       "  --"OPT_VMWARE_TSC_MAP"    Use VMware TSC map instead of native RDTSC\n"
 	       "  --"OPT_PROC_TYPE"         Type of this process (primary|secondary|auto)\n"
 	       "  --"OPT_SYSLOG"            Set syslog facility\n"