[dpdk-dev] [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.

Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
---
 config/common_linuxapp                     |  3 ++
 lib/librte_eal/common/eal_common_options.c |  1 +
 lib/librte_eal/linuxapp/eal/eal.c          | 48 ++++++++++++++++++++++++++++++
 3 files changed, 52 insertions(+)

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 1f459ac..4dba608 100644
--- a/lib/librte_eal/common/eal_common_options.c
+++ b/lib/librte_eal/common/eal_common_options.c
@@ -58,6 +58,7 @@ eal_short_options[] =
 	"b:" /* pci-blacklist */
 	"c:" /* coremask */
 	"d:" /* driver */
+	"D:" /* driver directory */
 	"h"  /* help */
 	"l:" /* corelist */
 	"m:" /* memory size */
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 31f3915..bbb02f0 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -50,6 +50,8 @@
 #include <errno.h>
 #include <sys/mman.h>
 #include <sys/queue.h>
+#include <sys/types.h>
+#include <dirent.h>
 #if defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_I686)
 #include <sys/io.h>
 #endif
@@ -104,6 +106,9 @@ 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_SOLIB_PATH;
+
 /* early configuration structure, when memory config is not mmapped */
 static struct rte_mem_config early_mem_config;
 
@@ -351,6 +356,7 @@ eal_usage(const char *prgname)
 	eal_common_usage();
 	printf("EAL Linux options:\n"
 	       "  -d LIB.so           Add driver (can be used multiple times)\n"
+	       "  -D DIRECTORY        Add driver directory\n"
 	       "  --"OPT_SOCKET_MEM"        Memory to allocate on sockets (comma separated values)\n"
 	       "  --"OPT_HUGE_DIR"          Directory where hugetlbfs is mounted\n"
 	       "  --"OPT_FILE_PREFIX"       Prefix for hugepage filenames\n"
@@ -548,6 +554,40 @@ eal_add_solib(const char *path)
 	return 0;
 }
 
+static int
+eal_add_solib_dir(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_add_solib(sopath) == -1)
+			break;
+	}
+
+	closedir(d);
+
+	/* XXX this ignores failures from readdir() itself */
+	return (dent == NULL) ? 0 : -1;
+}
+
 /* Parse the argument given in the command line of the application */
 static int
 eal_parse_args(int argc, char **argv)
@@ -591,6 +631,11 @@ eal_parse_args(int argc, char **argv)
 				return -1;
 			break;
 
+		/* set external driver directory */
+		case 'D':
+			solib_dir = optarg;
+			break;
+
 		/* long options */
 		case OPT_XEN_DOM0_NUM:
 #ifdef RTE_LIBRTE_XEN_DOM0
@@ -837,6 +882,9 @@ rte_eal_init(int argc, char **argv)
 
 	rte_eal_mcfg_complete();
 
+	if (eal_add_solib_dir(solib_dir) == -1)
+		rte_panic("Cannot init plugin directory %s\n", solib_dir);
+
 	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);
-- 
2.4.3