From 3218c0fc3b87a634415114bc6ee84444d8399f43 Mon Sep 17 00:00:00 2001

From: Adrien Mazarguil <adrien.mazarguil@6wind.com>

Date: Thu, 1 Feb 2018 14:30:57 +0100

Subject: [PATCH 8/9] net/mlx: make rdma-core glue path configurable

Since rdma-core glue libraries are intrinsically tied to their respective

PMDs and used as internal plug-ins, their presence in the default search

path among other system libraries for the dynamic linker is not necessarily

desired.

This commit enables their installation and subsequent look-up at run time

in RTE_EAL_PMD_PATH if configured to a nonempty string. This path can also

be overridden by environment variables MLX[45]_GLUE_PATH.

Signed-off-by: Adrien Mazarguil <adrien.mazarguil@6wind.com>

(cherry picked from commit 4143e796d50334d4d13e1b2c98139f2ac08c8178)

---

 doc/guides/nics/mlx4.rst | 17 +++++++++++++++++

 doc/guides/nics/mlx5.rst | 14 ++++++++++++++

 drivers/net/mlx4/mlx4.c  | 43 ++++++++++++++++++++++++++++++++++++++++++-

 drivers/net/mlx5/mlx5.c  | 43 ++++++++++++++++++++++++++++++++++++++++++-

 4 files changed, 115 insertions(+), 2 deletions(-)

diff --git a/doc/guides/nics/mlx4.rst b/doc/guides/nics/mlx4.rst

index 5912722..19ccf9c 100644

--- a/doc/guides/nics/mlx4.rst

+++ b/doc/guides/nics/mlx4.rst

@@ -97,6 +97,11 @@ These options can be modified in the ``.config`` file.

   ``CONFIG_RTE_BUILD_SHARED_LIB`` disabled) and they won't show up as

   missing with ``ldd(1)``.

+  It works by moving these dependencies to a purpose-built rdma-core "glue"

+  plug-in, which must either be installed in ``CONFIG_RTE_EAL_PMD_PATH`` if

+  set, or in a standard location for the dynamic linker (e.g. ``/lib``) if

+  left to the default empty string (``""``).

+

   This option has no performance impact.

 - ``CONFIG_RTE_LIBRTE_MLX4_DEBUG`` (default **n**)

@@ -121,6 +126,18 @@ These options can be modified in the ``.config`` file.

   This value is always 1 for RX queues since they use a single MP.

+Environment variables

+~~~~~~~~~~~~~~~~~~~~~

+

+- ``MLX4_GLUE_PATH``

+

+  A list of directories in which to search for the rdma-core "glue" plug-in,

+  separated by colons or semi-colons.

+

+  Only matters when compiled with ``CONFIG_RTE_LIBRTE_MLX4_DLOPEN_DEPS``

+  enabled and most useful when ``CONFIG_RTE_EAL_PMD_PATH`` is also set,

+  since ``LD_LIBRARY_PATH`` has no effect in this case.

+

 Run-time configuration

 ~~~~~~~~~~~~~~~~~~~~~~

diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst

index 6ee4a47..5f53eed 100644

--- a/doc/guides/nics/mlx5.rst

+++ b/doc/guides/nics/mlx5.rst

@@ -157,6 +157,11 @@ These options can be modified in the ``.config`` file.

   ``CONFIG_RTE_BUILD_SHARED_LIB`` disabled) and they won't show up as

   missing with ``ldd(1)``.

+  It works by moving these dependencies to a purpose-built rdma-core "glue"

+  plug-in, which must either be installed in ``CONFIG_RTE_EAL_PMD_PATH`` if

+  set, or in a standard location for the dynamic linker (e.g. ``/lib``) if

+  left to the default empty string (``""``).

+

   This option has no performance impact.

 - ``CONFIG_RTE_LIBRTE_MLX5_DEBUG`` (default **n**)

@@ -176,6 +181,15 @@ These options can be modified in the ``.config`` file.

 Environment variables

 ~~~~~~~~~~~~~~~~~~~~~

+- ``MLX5_GLUE_PATH``

+

+  A list of directories in which to search for the rdma-core "glue" plug-in,

+  separated by colons or semi-colons.

+

+  Only matters when compiled with ``CONFIG_RTE_LIBRTE_MLX5_DLOPEN_DEPS``

+  enabled and most useful when ``CONFIG_RTE_EAL_PMD_PATH`` is also set,

+  since ``LD_LIBRARY_PATH`` has no effect in this case.

+

 - ``MLX5_PMD_ENABLE_PADDING``

   Enables HW packet padding in PCI bus transactions.

diff --git a/drivers/net/mlx4/mlx4.c b/drivers/net/mlx4/mlx4.c

index e41acf1..6b29a8b 100644

--- a/drivers/net/mlx4/mlx4.c

+++ b/drivers/net/mlx4/mlx4.c

@@ -712,11 +712,52 @@ struct mlx4_conf {

 static int

 mlx4_glue_init(void)

 {

+	const char *path[] = {

+		/*

+		 * A basic security check is necessary before trusting

+		 * MLX4_GLUE_PATH, which may override RTE_EAL_PMD_PATH.

+		 */

+		(geteuid() == getuid() && getegid() == getgid() ?

+		 getenv("MLX4_GLUE_PATH") : NULL),

+		RTE_EAL_PMD_PATH,

+	};

+	unsigned int i = 0;

 	void *handle = NULL;

 	void **sym;

 	const char *dlmsg;

-	handle = dlopen(MLX4_GLUE, RTLD_LAZY);

+	while (!handle && i != RTE_DIM(path)) {

+		const char *end;

+		size_t len;

+		int ret;

+

+		if (!path[i]) {

+			++i;

+			continue;

+		}

+		end = strpbrk(path[i], ":;");

+		if (!end)

+			end = path[i] + strlen(path[i]);

+		len = end - path[i];

+		ret = 0;

+		do {

+			char name[ret + 1];

+

+			ret = snprintf(name, sizeof(name), "%.*s%s" MLX4_GLUE,

+				       (int)len, path[i],

+				       (!len || *(end - 1) == '/') ? "" : "/");

+			if (ret == -1)

+				break;

+			if (sizeof(name) != (size_t)ret + 1)

+				continue;

+			DEBUG("looking for rdma-core glue as \"%s\"", name);

+			handle = dlopen(name, RTLD_LAZY);

+			break;

+		} while (1);

+		path[i] = end + 1;

+		if (!*end)

+			++i;

+	}

 	if (!handle) {

 		rte_errno = EINVAL;

 		dlmsg = dlerror();

diff --git a/drivers/net/mlx5/mlx5.c b/drivers/net/mlx5/mlx5.c

index 6618d2c..403e26b 100644

--- a/drivers/net/mlx5/mlx5.c

+++ b/drivers/net/mlx5/mlx5.c

@@ -1033,11 +1033,52 @@ struct mlx5_args {

 static int

 mlx5_glue_init(void)

 {

+	const char *path[] = {

+		/*

+		 * A basic security check is necessary before trusting

+		 * MLX5_GLUE_PATH, which may override RTE_EAL_PMD_PATH.

+		 */

+		(geteuid() == getuid() && getegid() == getgid() ?

+		 getenv("MLX5_GLUE_PATH") : NULL),

+		RTE_EAL_PMD_PATH,

+	};

+	unsigned int i = 0;

 	void *handle = NULL;

 	void **sym;

 	const char *dlmsg;

-	handle = dlopen(MLX5_GLUE, RTLD_LAZY);

+	while (!handle && i != RTE_DIM(path)) {

+		const char *end;

+		size_t len;

+		int ret;

+

+		if (!path[i]) {

+			++i;

+			continue;

+		}

+		end = strpbrk(path[i], ":;");

+		if (!end)

+			end = path[i] + strlen(path[i]);

+		len = end - path[i];

+		ret = 0;

+		do {

+			char name[ret + 1];

+

+			ret = snprintf(name, sizeof(name), "%.*s%s" MLX5_GLUE,

+				       (int)len, path[i],

+				       (!len || *(end - 1) == '/') ? "" : "/");

+			if (ret == -1)

+				break;

+			if (sizeof(name) != (size_t)ret + 1)

+				continue;

+			DEBUG("looking for rdma-core glue as \"%s\"", name);

+			handle = dlopen(name, RTLD_LAZY);

+			break;

+		} while (1);

+		path[i] = end + 1;

+		if (!*end)

+			++i;

+	}

 	if (!handle) {

 		rte_errno = EINVAL;

 		dlmsg = dlerror();

-- 

1.8.3.1