[dpdk-dev,v1,2/4] net/mlx4: spawn rdma-core dependency plug-in

diff --git a/drivers/net/mlx4/Makefile b/drivers/net/mlx4/Makefile
index 1d33c38ed..2ebe61e90 100644
--- a/drivers/net/mlx4/Makefile
+++ b/drivers/net/mlx4/Makefile
@@ -38,7 +38,11 @@  LIB = librte_pmd_mlx4.a
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_ethdev.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_flow.c
+ifneq ($(CONFIG_RTE_BUILD_SHARED_LIB),y)
+SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_glue_lib.c
+else
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_glue.c
+endif
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_intr.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_mr.c
 SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD) += mlx4_rxq.c
@@ -55,7 +59,12 @@  CFLAGS += -D_BSD_SOURCE
 CFLAGS += -D_DEFAULT_SOURCE
 CFLAGS += -D_XOPEN_SOURCE=600
 CFLAGS += $(WERROR_FLAGS)
+ifneq ($(CONFIG_RTE_BUILD_SHARED_LIB),y)
+CFLAGS_mlx4_glue.o += -fPIC
+LDLIBS += -ldl
+else
 LDLIBS += -libverbs -lmlx4
+endif
 LDLIBS += -lrte_eal -lrte_mbuf -lrte_mempool -lrte_ring
 LDLIBS += -lrte_ethdev -lrte_net -lrte_kvargs
 LDLIBS += -lrte_bus_pci
@@ -109,7 +118,38 @@  mlx4_autoconf.h: mlx4_autoconf.h.new
 
 $(SRCS-$(CONFIG_RTE_LIBRTE_MLX4_PMD):.c=.o): mlx4_autoconf.h
 
+# Generate dependency plug-in for rdma-core when the PMD cannot be linked
+# directly, so that applications do not inherit this dependency.
+
+ifneq ($(CONFIG_RTE_BUILD_SHARED_LIB),y)
+
+mlx4_glue_lib.c: mlx4_glue_lib.so
+	$Q printf '#include <stddef.h>\n' > $@
+	$Q printf '#include <stdint.h>\n\n' >> $@
+	$Q printf 'const uint8_t mlx4_glue_lib[][16] = {\n' >> $@
+	$Q od -vt x1 $< | \
+	sed -ne '/^[[:xdigit:]]\{1,\}/{' \
+		-e 's///;' \
+		-e '/^$$/d; ' \
+		-e 's/[[:space:]]*$$//;' \
+		-e 's/[[:space:]]\{1,\}/\\x/g;' \
+		-e 's/^/	"/;' \
+		-e 's/$$/",/;' \
+		-e 'p;' \
+		-e '}' >> $@
+	$Q printf '};\n\n' >> $@
+	$Q printf 'const size_t mlx4_glue_lib_size = %u;' $$(wc -c < $<) >> $@
+
+mlx4_glue_lib.so: mlx4_glue.o
+	$Q $(LD) $(LDFLAGS) $(EXTRA_LDFLAGS) \
+		-s -shared -o $@ $< -libverbs -lmlx4
+
+mlx4_glue.o: mlx4_autoconf.h
+
+endif
+
 clean_mlx4: FORCE
 	$Q rm -f -- mlx4_autoconf.h mlx4_autoconf.h.new
+	$Q rm -f -- mlx4_glue.o mlx4_glue_lib.*
 
 clean: clean_mlx4
diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c
index 0fd9a999c..c173fbf56 100644
--- a/drivers/net/mlx4/mlx4.c
+++ b/drivers/net/mlx4/mlx4.c
@@ -37,6 +37,7 @@ 
  */
 
 #include <assert.h>
+#include <dlfcn.h>
 #include <errno.h>
 #include <inttypes.h>
 #include <stddef.h>
@@ -44,6 +45,7 @@ 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 /* Verbs headers do not support -pedantic. */
 #ifdef PEDANTIC
@@ -55,6 +57,7 @@ 
 #endif
 
 #include <rte_common.h>
+#include <rte_config.h>
 #include <rte_dev.h>
 #include <rte_errno.h>
 #include <rte_ethdev_driver.h>
@@ -724,6 +727,78 @@  static struct rte_pci_driver mlx4_driver = {
 		     RTE_PCI_DRV_INTR_RMV,
 };
 
+#ifndef RTE_BUILD_SHARED_LIB
+
+extern const uint8_t mlx4_glue_lib[][16];
+extern const size_t mlx4_glue_lib_size;
+
+/**
+ * Initialization routine for run-time dependency on rdma-core.
+ */
+static int
+mlx4_glue_init(void)
+{
+	char file[] = "/tmp/" MLX4_DRIVER_NAME "_XXXXXX";
+	int fd = mkstemp(file);
+	size_t off = 0;
+	void *handle = NULL;
+	void **sym;
+	const char *dlmsg;
+
+	if (fd == -1) {
+		rte_errno = errno;
+		goto glue_error;
+	}
+	while (off != mlx4_glue_lib_size) {
+		ssize_t ret;
+
+		ret = write(fd, (const uint8_t *)mlx4_glue_lib + off,
+			    mlx4_glue_lib_size - off);
+		if (ret == -1) {
+			if (errno != EINTR) {
+				rte_errno = errno;
+				goto glue_error;
+			}
+			ret = 0;
+		}
+		off += ret;
+	}
+	close(fd);
+	fd = -1;
+	handle = dlopen(file, RTLD_LAZY);
+	unlink(file);
+	if (!handle) {
+		rte_errno = EINVAL;
+		dlmsg = dlerror();
+		if (dlmsg)
+			ERROR("cannot load glue library: %s", dlmsg);
+		goto glue_error;
+	}
+	sym = dlsym(handle, "mlx4_glue");
+	if (!sym || !*sym) {
+		rte_errno = EINVAL;
+		dlmsg = dlerror();
+		if (dlmsg)
+			ERROR("cannot resolve glue symbol: %s", dlmsg);
+		goto glue_error;
+	}
+	mlx4_glue = *sym;
+	return 0;
+glue_error:
+	if (handle)
+		dlclose(handle);
+	if (fd != -1) {
+		close(fd);
+		unlink(file);
+	}
+	ERROR("cannot initialize PMD due to missing run-time"
+	      " dependency on rdma-core libraries (libibverbs,"
+	      " libmlx4)");
+	return -rte_errno;
+}
+
+#endif
+
 /**
  * Driver initialization routine.
  */
@@ -744,6 +819,11 @@  rte_mlx4_pmd_init(void)
 	 * using this PMD, which is not supported in forked processes.
 	 */
 	setenv("RDMAV_HUGEPAGES_SAFE", "1", 1);
+#ifndef RTE_BUILD_SHARED_LIB
+	if (mlx4_glue_init())
+		return;
+	assert(mlx4_glue);
+#endif
 	mlx4_glue->fork_init();
 	rte_pci_register(&mlx4_driver);
 }
diff --git a/mk/rte.app.mk b/mk/rte.app.mk
index 0169f3f5b..f9ac0e620 100644
--- a/mk/rte.app.mk
+++ b/mk/rte.app.mk
@@ -143,7 +143,7 @@  ifeq ($(CONFIG_RTE_LIBRTE_KNI),y)
 _LDLIBS-$(CONFIG_RTE_LIBRTE_PMD_KNI)        += -lrte_pmd_kni
 endif
 _LDLIBS-$(CONFIG_RTE_LIBRTE_LIO_PMD)        += -lrte_pmd_lio
-_LDLIBS-$(CONFIG_RTE_LIBRTE_MLX4_PMD)       += -lrte_pmd_mlx4 -libverbs -lmlx4
+_LDLIBS-$(CONFIG_RTE_LIBRTE_MLX4_PMD)       += -lrte_pmd_mlx4 -ldl
 _LDLIBS-$(CONFIG_RTE_LIBRTE_MLX5_PMD)       += -lrte_pmd_mlx5 -libverbs -lmlx5
 _LDLIBS-$(CONFIG_RTE_LIBRTE_MRVL_PMD)       += -lrte_pmd_mrvl -L$(LIBMUSDK_PATH)/lib -lmusdk
 _LDLIBS-$(CONFIG_RTE_LIBRTE_NFP_PMD)        += -lrte_pmd_nfp