[lxc-devel] [lxcfs/master] tree-wide: add and use must_make_path_relative()

[brauner on Github]

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From 925d5849986f5a3d5a819eecdbaa066c94a2d1bb Mon Sep 17 00:00:00 2001
From: Christian Brauner <christian.brauner at ubuntu.com>
Date: Mon, 16 Mar 2020 22:16:51 +0100
Subject: [PATCH] tree-wide: add and use must_make_path_relative()

Signed-off-by: Christian Brauner <christian.brauner at ubuntu.com>
---
 src/cgroups/cgfsng.c       | 29 +++++------------------------
 src/cgroups/cgroup_utils.h | 10 ++++++++++
 src/proc_cpuview.c         |  6 +-----
 3 files changed, 16 insertions(+), 29 deletions(-)

diff --git a/src/cgroups/cgfsng.c b/src/cgroups/cgfsng.c
index 4d4d4b2..8d3c53d 100644
--- a/src/cgroups/cgfsng.c
+++ b/src/cgroups/cgfsng.c
@@ -537,11 +537,7 @@ static bool cgfsng_get(struct cgroup_ops *ops, const char *controller,
 	if (!h)
 		return false;
 
-	if (is_relative(cgroup))
-		path = must_make_path(cgroup, file, NULL);
-	else
-		path = must_make_path(".", cgroup, file, NULL);
-
+	path = must_make_path_relative(cgroup, file, NULL);
 	*value = readat_file(h->fd, path);
 	return *value != NULL;
 }
@@ -571,11 +567,7 @@ static int cgfsng_get_memory(struct cgroup_ops *ops, const char *cgroup,
 		ret = CGROUP2_SUPER_MAGIC;
 	}
 
-	if (is_relative(cgroup))
-		path = must_make_path(cgroup, file, NULL);
-	else
-		path = must_make_path(".", cgroup, file, NULL);
-
+	path = must_make_path_relative(cgroup, file, NULL);
 	*value = readat_file(h->fd, path);
 	if (!*value)
 		ret = -1;
@@ -592,11 +584,7 @@ static int cgfsng_get_memory_stats_fd(struct cgroup_ops *ops, const char *cgroup
 	if (!h)
 		return -1;
 
-	if (is_relative(cgroup))
-		path = must_make_path(cgroup, "memory.stat", NULL);
-	else
-		path = must_make_path(".", cgroup, "memory.stat", NULL);
-
+	path = must_make_path_relative(cgroup, "memory.stat", NULL);
 	return openat(h->fd, path, O_RDONLY | O_CLOEXEC | O_NOFOLLOW);
 }
 
@@ -665,10 +653,7 @@ static int cgfsng_get_cpuset_cpus(struct cgroup_ops *ops, const char *cgroup,
 		ret = CGROUP2_SUPER_MAGIC;
 
 	*value = NULL;
-	if (is_relative(cgroup))
-		path = must_make_path(cgroup, NULL);
-	else
-		path = must_make_path(".", cgroup, NULL);
+	path = must_make_path_relative(cgroup, NULL);
 	cgroup_fd = openat_safe(h->fd, path);
 	if (cgroup_fd < 0) {
 		return -1;
@@ -718,11 +703,7 @@ static int cgfsng_get_io(struct cgroup_ops *ops, const char *cgroup,
 	else
 		ret = CGROUP2_SUPER_MAGIC;
 
-	if (is_relative(cgroup))
-		path = must_make_path(cgroup, file, NULL);
-	else
-		path = must_make_path(".", cgroup, file, NULL);
-
+	path = must_make_path_relative(cgroup, file, NULL);
 	*value = readat_file(h->fd, path);
 	if (!*value) {
 		if (errno == ENOENT)
diff --git a/src/cgroups/cgroup_utils.h b/src/cgroups/cgroup_utils.h
index 35e5a98..e626e3f 100644
--- a/src/cgroups/cgroup_utils.h
+++ b/src/cgroups/cgroup_utils.h
@@ -107,4 +107,14 @@ static inline bool is_relative(const char *s)
 	return s && *s != '/';
 }
 
+#define must_make_path_relative(__first__, ...)                                \
+	({                                                                     \
+		char *__ptr__;                                                 \
+		if (*__first__ == '/')                                         \
+			__ptr__ = must_make_path(".", __first__, __VA_ARGS__); \
+		else                                                           \
+			__ptr__ = must_make_path(__first__, __VA_ARGS__);      \
+		__ptr__;                                                       \
+	})
+
 #endif /* __LXC_CGROUP_UTILS_H */
diff --git a/src/proc_cpuview.c b/src/proc_cpuview.c
index 129e192..5c21bc4 100644
--- a/src/proc_cpuview.c
+++ b/src/proc_cpuview.c
@@ -243,11 +243,7 @@ static bool cgfs_param_exist(const char *controller, const char *cgroup,
 	if (cfd < 0)
 		return false;
 
-	if (is_relative(cgroup))
-		path = must_make_path(cgroup, file, NULL);
-	else
-		path = must_make_path(".", cgroup, file, NULL);
-
+	path = must_make_path_relative(cgroup, file, NULL);
 	return (faccessat(cfd, path, F_OK, 0) == 0);
 }