[dpdk-dev] [PATCH v3 3/4] eal: add directory for DPDK runtime data

[Anatoly Burakov <anatoly.burakov@intel.com>]

Currently, during runtime, DPDK will store a bunch of files here
and there (in /var/run, /tmp or in $HOME). Fix it by creating a
DPDK-specific runtime directory, under which all runtime data
will be placed. The template for creating this runtime directory
is the following:

  <base path>/dpdk/<DPDK prefix>/

Where <base path> is set to either "/var/run" if run as root, or
$XDG_RUNTIME_DIR if run as non-root, with a fallback to /tmp if
$XDG_RUNTIME_DIR is not defined. So, for example, if run as root,
by default all runtime data will be stored at /var/run/dpdk/rte/.

There is no equivalent of "mkdir -p", so we will be creating the
path step by step.

Nothing uses this new path yet, changes for that will come in
next commit.

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
Reviewed-by: Reshma Pattan <reshma.pattan@intel.com>
---
 lib/librte_eal/bsdapp/eal/eal.c        | 68 ++++++++++++++++++++++++++++++++++
 lib/librte_eal/common/eal_filesystem.h |  8 ++++
 lib/librte_eal/linuxapp/eal/eal.c      | 67 +++++++++++++++++++++++++++++++++
 3 files changed, 143 insertions(+)

diff --git a/lib/librte_eal/bsdapp/eal/eal.c b/lib/librte_eal/bsdapp/eal/eal.c
index 3ba328a..de88b6a 100644
--- a/lib/librte_eal/bsdapp/eal/eal.c
+++ b/lib/librte_eal/bsdapp/eal/eal.c
@@ -18,6 +18,7 @@
 #include <limits.h>
 #include <sys/mman.h>
 #include <sys/queue.h>
+#include <sys/stat.h>
 
 #include <rte_compat.h>
 #include <rte_common.h>
@@ -83,6 +84,66 @@ struct internal_config internal_config;
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* platform-specific runtime dir */
+static char runtime_dir[PATH_MAX];
+
+int
+eal_create_runtime_dir(void)
+{
+	const char *directory = default_config_dir;
+	const char *xdg_runtime_dir = getenv("XDG_RUNTIME_DIR");
+	const char *fallback = "/tmp";
+	char tmp[PATH_MAX];
+	int ret;
+
+	if (getuid() != 0) {
+		/* try XDG path first, fall back to /tmp */
+		if (xdg_runtime_dir != NULL)
+			directory = xdg_runtime_dir;
+		else
+			directory = fallback;
+	}
+	/* create DPDK subdirectory under runtime dir */
+	ret = snprintf(tmp, sizeof(tmp), "%s/dpdk", directory);
+	if (ret < 0 || ret == sizeof(tmp)) {
+		RTE_LOG(ERR, EAL, "Error creating DPDK runtime path name\n");
+		return -1;
+	}
+
+	/* create prefix-specific subdirectory under DPDK runtime dir */
+	ret = snprintf(runtime_dir, sizeof(runtime_dir), "%s/%s",
+			tmp, internal_config.hugefile_prefix);
+	if (ret < 0 || ret == sizeof(runtime_dir)) {
+		RTE_LOG(ERR, EAL, "Error creating prefix-specific runtime path name\n");
+		return -1;
+	}
+
+	/* create the path if it doesn't exist. no "mkdir -p" here, so do it
+	 * step by step.
+	 */
+	ret = mkdir(tmp, 0600);
+	if (ret < 0 && errno != EEXIST) {
+		RTE_LOG(ERR, EAL, "Error creating '%s': %s\n",
+			tmp, strerror(errno));
+		return -1;
+	}
+
+	ret = mkdir(runtime_dir, 0600);
+	if (ret < 0 && errno != EEXIST) {
+		RTE_LOG(ERR, EAL, "Error creating '%s': %s\n",
+			runtime_dir, strerror(errno));
+		return -1;
+	}
+
+	return 0;
+}
+
+const char *
+eal_get_runtime_dir(void)
+{
+	return runtime_dir;
+}
+
 /* Return user provided mbuf pool ops name */
 const char * __rte_experimental
 rte_eal_mbuf_user_pool_ops(void)
@@ -523,6 +584,13 @@ rte_eal_init(int argc, char **argv)
 	/* set log level as early as possible */
 	eal_log_level_parse(argc, argv);
 
+	/* create runtime data directory */
+	if (eal_create_runtime_dir() < 0) {
+		rte_eal_init_alert("Cannot create runtime directory\n");
+		rte_errno = EACCES;
+		return -1;
+	}
+
 	if (rte_eal_cpu_init() < 0) {
 		rte_eal_init_alert("Cannot detect lcores.");
 		rte_errno = ENOTSUP;
diff --git a/lib/librte_eal/common/eal_filesystem.h b/lib/librte_eal/common/eal_filesystem.h
index 060ac2b..67f5ca8 100644
--- a/lib/librte_eal/common/eal_filesystem.h
+++ b/lib/librte_eal/common/eal_filesystem.h
@@ -25,6 +25,14 @@
 
 static const char *default_config_dir = "/var/run";
 
+/* sets up platform-specific runtime data dir */
+int
+eal_create_runtime_dir(void);
+
+/* returns runtime dir */
+const char *
+eal_get_runtime_dir(void);
+
 static inline const char *
 eal_runtime_config_path(void)
 {
diff --git a/lib/librte_eal/linuxapp/eal/eal.c b/lib/librte_eal/linuxapp/eal/eal.c
index 34d9412..6048063 100644
--- a/lib/librte_eal/linuxapp/eal/eal.c
+++ b/lib/librte_eal/linuxapp/eal/eal.c
@@ -92,6 +92,66 @@ struct internal_config internal_config;
 /* used by rte_rdtsc() */
 int rte_cycles_vmware_tsc_map;
 
+/* platform-specific runtime dir */
+static char runtime_dir[PATH_MAX];
+
+int
+eal_create_runtime_dir(void)
+{
+	const char *directory = default_config_dir;
+	const char *xdg_runtime_dir = getenv("XDG_RUNTIME_DIR");
+	const char *fallback = "/tmp";
+	char tmp[PATH_MAX];
+	int ret;
+
+	if (getuid() != 0) {
+		/* try XDG path first, fall back to /tmp */
+		if (xdg_runtime_dir != NULL)
+			directory = xdg_runtime_dir;
+		else
+			directory = fallback;
+	}
+	/* create DPDK subdirectory under runtime dir */
+	ret = snprintf(tmp, sizeof(tmp), "%s/dpdk", directory);
+	if (ret < 0 || ret == sizeof(tmp)) {
+		RTE_LOG(ERR, EAL, "Error creating DPDK runtime path name\n");
+		return -1;
+	}
+
+	/* create prefix-specific subdirectory under DPDK runtime dir */
+	ret = snprintf(runtime_dir, sizeof(runtime_dir), "%s/%s",
+			tmp, internal_config.hugefile_prefix);
+	if (ret < 0 || ret == sizeof(runtime_dir)) {
+		RTE_LOG(ERR, EAL, "Error creating prefix-specific runtime path name\n");
+		return -1;
+	}
+
+	/* create the path if it doesn't exist. no "mkdir -p" here, so do it
+	 * step by step.
+	 */
+	ret = mkdir(tmp, 0600);
+	if (ret < 0 && errno != EEXIST) {
+		RTE_LOG(ERR, EAL, "Error creating '%s': %s\n",
+			tmp, strerror(errno));
+		return -1;
+	}
+
+	ret = mkdir(runtime_dir, 0600);
+	if (ret < 0 && errno != EEXIST) {
+		RTE_LOG(ERR, EAL, "Error creating '%s': %s\n",
+			runtime_dir, strerror(errno));
+		return -1;
+	}
+
+	return 0;
+}
+
+const char *
+eal_get_runtime_dir(void)
+{
+	return runtime_dir;
+}
+
 /* Return user provided mbuf pool ops name */
 const char * __rte_experimental
 rte_eal_mbuf_user_pool_ops(void)
@@ -741,6 +801,13 @@ rte_eal_init(int argc, char **argv)
 	/* set log level as early as possible */
 	eal_log_level_parse(argc, argv);
 
+	/* create runtime data directory */
+	if (eal_create_runtime_dir() < 0) {
+		rte_eal_init_alert("Cannot create runtime directory\n");
+		rte_errno = EACCES;
+		return -1;
+	}
+
 	if (rte_eal_cpu_init() < 0) {
 		rte_eal_init_alert("Cannot detect lcores.");
 		rte_errno = ENOTSUP;
-- 
2.7.4