[PATCH] examples: Fix vm_power_manager scratch area to /run/dpdk/powermanager

[PATCH] examples: Fix vm_power_manager scratch area to /run/dpdk/powermanager

[Sudheendra Sampath]

This patch for bug 1832 will do the following:
1.  If /run/dpdk is not present, it will create it first with and
    then create powermanager directory underneath it.
2.  If /run/dpdk is present, it will verify it is actually a directory
    before creating subdirectory, powermanager.

All directory permissions are 0700.

Signed-off-by: Sudheendra Sampath <giveback4fun@gmail.com>
---
 examples/vm_power_manager/channel_manager.c | 27 ++++++++++++++++++++-
 examples/vm_power_manager/channel_manager.h |  2 +-
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/examples/vm_power_manager/channel_manager.c b/examples/vm_power_manager/channel_manager.c
index b69449c61d..60d767ea98 100644
--- a/examples/vm_power_manager/channel_manager.c
+++ b/examples/vm_power_manager/channel_manager.c
@@ -420,8 +420,33 @@ add_all_channels(const char *vm_name)
 	if (d == NULL) {
 		RTE_LOG(ERR, CHANNEL_MANAGER, "Error opening directory '%s': %s\n",
 				CHANNEL_MGR_SOCKET_PATH, strerror(errno));
-		return -1;
+
+		const char *run_dpdk = "/run/dpdk";
+		struct stat path_stat;
+		int ret;
+
+		if (stat(run_dpdk, &path_stat) != 0) {
+			ret = mkdir(run_dpdk, 0700);
+			if (ret < 0 && errno != EEXIST) {
+				RTE_LOG(ERR, CHANNEL_MANAGER, "Error creating '%s': %s",
+						run_dpdk, strerror(errno));
+				return -1;
+			}
+		}
+
+		/* Make sure /run/dpdk is a directory */
+		if (!S_ISDIR(path_stat.st_mode)) {
+			return -1;
+		}
+
+		ret = mkdir(CHANNEL_MGR_SOCKET_PATH, 0700);
+		if (ret < 0 && errno != EEXIST) {
+			RTE_LOG(ERR, CHANNEL_MANAGER, "Error creating '%s': %s",
+				CHANNEL_MGR_SOCKET_PATH, strerror(errno));
+			return -1;
+		}
 	}
+
 	while ((dir = readdir(d)) != NULL) {
 		if (!strncmp(dir->d_name, ".", 1) ||
 				!strncmp(dir->d_name, "..", 2))
diff --git a/examples/vm_power_manager/channel_manager.h b/examples/vm_power_manager/channel_manager.h
index 6f70539815..5fc93ae0be 100644
--- a/examples/vm_power_manager/channel_manager.h
+++ b/examples/vm_power_manager/channel_manager.h
@@ -22,7 +22,7 @@ extern "C" {
 #define CHANNEL_MGR_DEFAULT_HV_PATH "qemu:///system"
 
 /* File socket directory */
-#define CHANNEL_MGR_SOCKET_PATH     "/tmp/powermonitor/"
+#define CHANNEL_MGR_SOCKET_PATH     "/run/dpdk/powermonitor/"
 
 /* FIFO file name template */
 #define CHANNEL_MGR_FIFO_PATTERN_NAME   "fifo"
-- 
2.43.0

Re: [PATCH] examples: Fix vm_power_manager scratch area to /run/dpdk/powermanager

[Stephen Hemminger]

On Thu, 28 May 2026 19:04:48 +0000
Sudheendra Sampath <giveback4fun@gmail.com> wrote:

> This patch for bug 1832 will do the following:
> 1.  If /run/dpdk is not present, it will create it first with and
>     then create powermanager directory underneath it.
> 2.  If /run/dpdk is present, it will verify it is actually a directory
>     before creating subdirectory, powermanager.
> 
> All directory permissions are 0700.
> 
> Signed-off-by: Sudheendra Sampath <giveback4fun@gmail.com>
> ---

Lots of issues with hardcoding the path here.
Longer explanation from AI review.


Thanks for the patch. A few issues to address before this can be merged:

Two correctness bugs in the new recovery block:

- After creating the directories, d is still NULL but the code falls through to readdir(d). The recovery path must call opendir() again (and return -1 if that also fails) before the readdir loop.

- path_stat is only populated when stat() succeeds. The S_ISDIR(path_stat.st_mode) check runs on uninitialised memory when stat() returned an error and mkdir() was used. Restructure as if (stat(...) == 0) { check S_ISDIR } else { mkdir }.

Other items:

- doc/guides/sample_app_ug/vm_power_management.rst still references /tmp/powermonitor/ in several places; code and docs need to change together.

- Hardcoding /run/dpdk does not follow the DPDK runtime-dir convention and breaks non-root usage. 
  Please consider using rte_eal_get_runtime_dir() (or at least the same getuid() / RUNTIME_DIRECTORY logic as eal_create_runtime_dir()) instead.

- Subject says "powermanager" but the path is "powermonitor".

- The two new RTE_LOG messages are missing trailing "\n".

- Please add a proper Fixes: tag (12-char hash) for the commit that introduced /tmp/powermonitor.

Stephen

Re: [PATCH] examples: Fix vm_power_manager scratch area to /run/dpdk/powermanager

[Bruce Richardson]

On Thu, May 28, 2026 at 07:04:48PM +0000, Sudheendra Sampath wrote:
> This patch for bug 1832 will do the following:
> 1.  If /run/dpdk is not present, it will create it first with and
>     then create powermanager directory underneath it.
> 2.  If /run/dpdk is present, it will verify it is actually a directory
>     before creating subdirectory, powermanager.
> 
I would suggest using $XDG_RUNTIME_DIR for the directory path, rather than
hardcoding it by default. If XDG_RUNTIME_DIR is not set, then maybe
consider using /run/dpdk. However, rather than /run/dpdk, I'd suggest using
the normal runtime dir path on most distros as the default:
/run/user/<uid>.

/Bruce

Re: [PATCH] examples: Fix vm_power_manager scratch area to /run/dpdk/powermanager

[Stephen Hemminger]

On Fri, 29 May 2026 09:01:34 +0100
Bruce Richardson <bruce.richardson@intel.com> wrote:

> On Thu, May 28, 2026 at 07:04:48PM +0000, Sudheendra Sampath wrote:
> > This patch for bug 1832 will do the following:
> > 1.  If /run/dpdk is not present, it will create it first with and
> >     then create powermanager directory underneath it.
> > 2.  If /run/dpdk is present, it will verify it is actually a directory
> >     before creating subdirectory, powermanager.
> >   
> I would suggest using $XDG_RUNTIME_DIR for the directory path, rather than
> hardcoding it by default. If XDG_RUNTIME_DIR is not set, then maybe
> consider using /run/dpdk. However, rather than /run/dpdk, I'd suggest using
> the normal runtime dir path on most distros as the default:
> /run/user/<uid>.
> 
> /Bruce

The login in EAL is a little more detailed.
The choice is from systemd conventions which follows filesystem hierarchy.


int eal_create_runtime_dir(void)
{
	const char *directory;
	char run_dir[PATH_MAX];
	char tmp[PATH_MAX];
	int ret;

	/* from RuntimeDirectory= see systemd.exec */
	directory = getenv("RUNTIME_DIRECTORY");
	if (directory == NULL) {
		/*
		 * Used standard convention defined in
		 * XDG Base Directory Specification and
		 * Filesystem Hierarchy Standard.
		 */
		if (getuid() == 0)
			directory = "/var/run";
		else
			directory = getenv("XDG_RUNTIME_DIR") ? : "/tmp";
	}

	/* create DPDK subdirectory under runtime dir */
	ret = snprintf(tmp, sizeof(tmp), "%s/dpdk", directory);
	if (ret < 0 || ret == sizeof(tmp)) {
		EAL_LOG(ERR, "Error creating DPDK runtime path name");
		return -1;
	}

	/* create prefix-specific subdirectory under DPDK runtime dir */
	ret = snprintf(run_dir, sizeof(run_dir), "%s/%s",
			tmp, eal_get_hugefile_prefix());
	if (ret < 0 || ret == sizeof(run_dir)) {
		EAL_LOG(ERR, "Error creating prefix-specific runtime path name");
		return -1;
	}

	/* create the path if it doesn't exist. no "mkdir -p" here, so do it
	 * step by step.
	 */
	ret = mkdir(tmp, 0700);
	if (ret < 0 && errno != EEXIST) {
		EAL_LOG(ERR, "Error creating '%s': %s",
			tmp, strerror(errno));
		return -1;
	}

	ret = mkdir(run_dir, 0700);
	if (ret < 0 && errno != EEXIST) {
		EAL_LOG(ERR, "Error creating '%s': %s",
			run_dir, strerror(errno));
		return -1;
	}

Re: [PATCH] examples: Fix vm_power_manager scratch area to /run/dpdk/powermanager

[Bruce Richardson]

On Fri, May 29, 2026 at 08:23:24AM -0700, Stephen Hemminger wrote:
> On Fri, 29 May 2026 09:01:34 +0100
> Bruce Richardson <bruce.richardson@intel.com> wrote:
> 
> > On Thu, May 28, 2026 at 07:04:48PM +0000, Sudheendra Sampath wrote:
> > > This patch for bug 1832 will do the following:
> > > 1.  If /run/dpdk is not present, it will create it first with and
> > >     then create powermanager directory underneath it.
> > > 2.  If /run/dpdk is present, it will verify it is actually a directory
> > >     before creating subdirectory, powermanager.
> > >   
> > I would suggest using $XDG_RUNTIME_DIR for the directory path, rather than
> > hardcoding it by default. If XDG_RUNTIME_DIR is not set, then maybe
> > consider using /run/dpdk. However, rather than /run/dpdk, I'd suggest using
> > the normal runtime dir path on most distros as the default:
> > /run/user/<uid>.
> > 
> > /Bruce
> 
> The login in EAL is a little more detailed.
> The choice is from systemd conventions which follows filesystem hierarchy.
> 
> 
> int eal_create_runtime_dir(void)
> {
> 	const char *directory;
> 	char run_dir[PATH_MAX];
> 	char tmp[PATH_MAX];
> 	int ret;
> 
> 	/* from RuntimeDirectory= see systemd.exec */
> 	directory = getenv("RUNTIME_DIRECTORY");
> 	if (directory == NULL) {
> 		/*
> 		 * Used standard convention defined in
> 		 * XDG Base Directory Specification and
> 		 * Filesystem Hierarchy Standard.
> 		 */
> 		if (getuid() == 0)
> 			directory = "/var/run";
> 		else
> 			directory = getenv("XDG_RUNTIME_DIR") ? : "/tmp";
> 	}
> 
> 	/* create DPDK subdirectory under runtime dir */
> 	ret = snprintf(tmp, sizeof(tmp), "%s/dpdk", directory);
> 	if (ret < 0 || ret == sizeof(tmp)) {
> 		EAL_LOG(ERR, "Error creating DPDK runtime path name");
> 		return -1;
> 	}
> 
> 	/* create prefix-specific subdirectory under DPDK runtime dir */
> 	ret = snprintf(run_dir, sizeof(run_dir), "%s/%s",
> 			tmp, eal_get_hugefile_prefix());
> 	if (ret < 0 || ret == sizeof(run_dir)) {
> 		EAL_LOG(ERR, "Error creating prefix-specific runtime path name");
> 		return -1;
> 	}
> 
> 	/* create the path if it doesn't exist. no "mkdir -p" here, so do it
> 	 * step by step.
> 	 */
> 	ret = mkdir(tmp, 0700);
> 	if (ret < 0 && errno != EEXIST) {
> 		EAL_LOG(ERR, "Error creating '%s': %s",
> 			tmp, strerror(errno));
> 		return -1;
> 	}
> 
> 	ret = mkdir(run_dir, 0700);
> 	if (ret < 0 && errno != EEXIST) {
> 		EAL_LOG(ERR, "Error creating '%s': %s",
> 			run_dir, strerror(errno));
> 		return -1;
> 	}

Yes. Can the power manager call the rte_eal_get_runtime_dir() API and use
that as a basis for its working directory? Save duplicating all this logic.

/Bruce