From 08c028d08c42c1a4cd26aff1ed9c6438ddfd1206 Mon Sep 17 00:00:00 2001

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

Date: Fri, 2 Mar 2018 15:15:17 +0100

Subject: [PATCH] net/mlx: fix rdma-core glue path with EAL plugins

Glue object files are looked up in RTE_EAL_PMD_PATH by default when set and

should be installed in this directory.

During startup, EAL attempts to load them automatically like other plug-ins

found there. While normally harmless, dlopen() fails when rdma-core is not

installed, EAL interprets this as a fatal error and terminates the

application.

This patch requests glue objects to be installed in a different directory

to prevent their automatic loading by EAL since they are PMD helpers, not

actual DPDK plug-ins.

Fixes: f6242d0655cd ("net/mlx: make rdma-core glue path configurable")

Cc: stable@dpdk.org

Reported-by: Timothy Redaelli <tredaelli@redhat.com>

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

Tested-by: Timothy Redaelli <tredaelli@redhat.com>

---

 doc/guides/nics/mlx4.rst |  7 +++---

 doc/guides/nics/mlx5.rst |  7 +++---

 drivers/net/mlx4/mlx4.c  | 50 +++++++++++++++++++++++++++++++++++++++-

 drivers/net/mlx5/mlx5.c  | 50 +++++++++++++++++++++++++++++++++++++++-

 4 files changed, 106 insertions(+), 8 deletions(-)

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

index 98b971667..afeff276e 100644

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

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

@@ -98,9 +98,10 @@ These options can be modified in the ``.config`` file.

   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 (``""``).

+  plug-in which must either be installed in a directory whose name is based

+  on ``CONFIG_RTE_EAL_PMD_PATH`` suffixed with ``-glue`` 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.

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

index 0e6e525c9..46d26e4c8 100644

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

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

@@ -171,9 +171,10 @@ These options can be modified in the ``.config`` file.

   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 (``""``).

+  plug-in which must either be installed in a directory whose name is based

+  on ``CONFIG_RTE_EAL_PMD_PATH`` suffixed with ``-glue`` 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.

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

index ee93dafe6..fb8a8b848 100644

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

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

@@ -707,12 +707,54 @@ static struct rte_pci_driver mlx4_driver = {

 #ifdef RTE_LIBRTE_MLX4_DLOPEN_DEPS

+/**

+ * Suffix RTE_EAL_PMD_PATH with "-glue".

+ *

+ * This function performs a sanity check on RTE_EAL_PMD_PATH before

+ * suffixing its last component.

+ *

+ * @param buf[out]

+ *   Output buffer, should be large enough otherwise NULL is returned.

+ * @param size

+ *   Size of @p out.

+ *

+ * @return

+ *   Pointer to @p buf or @p NULL in case suffix cannot be appended.

+ */

+static char *

+mlx4_glue_path(char *buf, size_t size)

+{

+	static const char *const bad[] = { "/", ".", "..", NULL };

+	const char *path = RTE_EAL_PMD_PATH;

+	size_t len = strlen(path);

+	size_t off;

+	int i;

+

+	while (len && path[len - 1] == '/')

+		--len;

+	for (off = len; off && path[off - 1] != '/'; --off)

+		;

+	for (i = 0; bad[i]; ++i)

+		if (!strncmp(path + off, bad[i], (int)(len - off)))

+			goto error;

+	i = snprintf(buf, size, "%.*s-glue", (int)len, path);

+	if (i == -1 || (size_t)i >= size)

+		goto error;

+	return buf;

+error:

+	ERROR("unable to append \"-glue\" to last component of"

+	      " RTE_EAL_PMD_PATH (\"" RTE_EAL_PMD_PATH "\"),"

+	      " please re-configure DPDK");

+	return NULL;

+}

+

 /**

  * Initialization routine for run-time dependency on rdma-core.

  */

 static int

 mlx4_glue_init(void)

 {

+	char glue_path[sizeof(RTE_EAL_PMD_PATH) - 1 + sizeof("-glue")];

 	const char *path[] = {

 		/*

 		 * A basic security check is necessary before trusting

@@ -720,7 +762,13 @@ mlx4_glue_init(void)

 		 */

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

 		 getenv("MLX4_GLUE_PATH") : NULL),

-		RTE_EAL_PMD_PATH,

+		/*

+		 * When RTE_EAL_PMD_PATH is set, use its glue-suffixed

+		 * variant, otherwise let dlopen() look up libraries on its

+		 * own.

+		 */

+		(*RTE_EAL_PMD_PATH ?

+		 mlx4_glue_path(glue_path, sizeof(glue_path)) : ""),

 	};

 	unsigned int i = 0;

 	void *handle = NULL;

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

index 61cb93101..0ca16d11d 100644

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

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

@@ -1042,12 +1042,54 @@ static struct rte_pci_driver mlx5_driver = {

 #ifdef RTE_LIBRTE_MLX5_DLOPEN_DEPS

+/**

+ * Suffix RTE_EAL_PMD_PATH with "-glue".

+ *

+ * This function performs a sanity check on RTE_EAL_PMD_PATH before

+ * suffixing its last component.

+ *

+ * @param buf[out]

+ *   Output buffer, should be large enough otherwise NULL is returned.

+ * @param size

+ *   Size of @p out.

+ *

+ * @return

+ *   Pointer to @p buf or @p NULL in case suffix cannot be appended.

+ */

+static char *

+mlx5_glue_path(char *buf, size_t size)

+{

+	static const char *const bad[] = { "/", ".", "..", NULL };

+	const char *path = RTE_EAL_PMD_PATH;

+	size_t len = strlen(path);

+	size_t off;

+	int i;

+

+	while (len && path[len - 1] == '/')

+		--len;

+	for (off = len; off && path[off - 1] != '/'; --off)

+		;

+	for (i = 0; bad[i]; ++i)

+		if (!strncmp(path + off, bad[i], (int)(len - off)))

+			goto error;

+	i = snprintf(buf, size, "%.*s-glue", (int)len, path);

+	if (i == -1 || (size_t)i >= size)

+		goto error;

+	return buf;

+error:

+	ERROR("unable to append \"-glue\" to last component of"

+	      " RTE_EAL_PMD_PATH (\"" RTE_EAL_PMD_PATH "\"),"

+	      " please re-configure DPDK");

+	return NULL;

+}

+

 /**

  * Initialization routine for run-time dependency on rdma-core.

  */

 static int

 mlx5_glue_init(void)

 {

+	char glue_path[sizeof(RTE_EAL_PMD_PATH) - 1 + sizeof("-glue")];

 	const char *path[] = {

 		/*

 		 * A basic security check is necessary before trusting

@@ -1055,7 +1097,13 @@ mlx5_glue_init(void)

 		 */

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

 		 getenv("MLX5_GLUE_PATH") : NULL),

-		RTE_EAL_PMD_PATH,

+		/*

+		 * When RTE_EAL_PMD_PATH is set, use its glue-suffixed

+		 * variant, otherwise let dlopen() look up libraries on its

+		 * own.

+		 */

+		(*RTE_EAL_PMD_PATH ?

+		 mlx5_glue_path(glue_path, sizeof(glue_path)) : ""),

 	};

 	unsigned int i = 0;

 	void *handle = NULL;

-- 

2.17.0