[PATCH 2/2] eal: add support for driver directory concept

[Panu Matilainen <pmatilai@redhat.com>]

Add a new EAL option -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 (but can be overridden or disabled with -D).

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>
Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
---
 config/common_bsdapp                       |  3 ++
 config/common_linuxapp                     |  3 ++
 lib/librte_eal/common/eal_common_options.c | 50 ++++++++++++++++++++++++++++++
 3 files changed, 56 insertions(+)

diff --git a/config/common_bsdapp b/config/common_bsdapp
index b37dcf4..13bccf4 100644
--- a/config/common_bsdapp
+++ b/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
 #
diff --git a/config/common_linuxapp b/config/common_linuxapp
index 0de43d5..a0d8cd2 100644
--- a/config/common_linuxapp
+++ b/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
 #
diff --git a/lib/librte_eal/common/eal_common_options.c b/lib/librte_eal/common/eal_common_options.c
index b542868..c2aca91 100644
--- a/lib/librte_eal/common/eal_common_options.c
+++ b/lib/librte_eal/common/eal_common_options.c
@@ -40,6 +40,8 @@
 #include <errno.h>
 #include <getopt.h>
 #include <dlfcn.h>
+#include <sys/types.h>
+#include <dirent.h>
 
 #include <rte_eal.h>
 #include <rte_log.h>
@@ -59,6 +61,7 @@ eal_short_options[] =
 	"b:" /* pci-blacklist */
 	"c:" /* coremask */
 	"d:" /* driver */
+	"D:" /* driver directory */
 	"h"  /* help */
 	"l:" /* corelist */
 	"m:" /* memory size */
@@ -108,6 +111,9 @@ struct shared_driver {
 static struct shared_driver_list solib_list =
 TAILQ_HEAD_INITIALIZER(solib_list);
 
+/* Path of external loadable drivers */
+static const char *solib_dir = RTE_EAL_PMD_PATH;
+
 static int lcores_parsed;
 static int master_lcore_parsed;
 static int mem_parsed;
@@ -167,11 +173,50 @@ 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 (eal_plugindir_init(solib_dir) == -1) {
+		RTE_LOG(ERR, EAL, "Cannot init plugin directory %s\n",
+			solib_dir);
+		return -1;
+	}
+
 	TAILQ_FOREACH(solib, &solib_list, next) {
 		RTE_LOG(DEBUG, EAL, "open shared lib %s\n", solib->name);
 		solib->lib_handle = dlopen(solib->name, RTLD_NOW);
@@ -768,6 +813,10 @@ eal_parse_common_option(int opt, const char *optarg,
 		if (eal_plugin_add(optarg) == -1)
 			return -1;
 		break;
+	/* set external driver directory */
+	case 'D':
+		solib_dir = optarg;
+		break;
 
 	/* long options */
 	case OPT_NO_HUGE_NUM:
@@ -955,6 +1004,7 @@ eal_common_usage(void)
 	       "  --"OPT_SYSLOG"            Set syslog facility\n"
 	       "  --"OPT_LOG_LEVEL"         Set default log level\n"
 	       "  -d LIB.so           Add driver (can be used multiple times)\n"
+	       "  -D DIRECTORY        Add driver directory)\n"
 	       "  -v                  Display version information on startup\n"
 	       "  -h, --help          This help\n"
 	       "\nEAL options for DEBUG use only:\n"
-- 
2.4.3