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[iproute2] lib/bpf: Fix and simplify bpf_mnt_check_target()

Message ID 0ecd47fcb87e5d02b020dbf578272607468dc625.1613995541.git.aclaudi@redhat.com
State New
Headers show
Series [iproute2] lib/bpf: Fix and simplify bpf_mnt_check_target() | expand

Commit Message

Andrea Claudi Feb. 22, 2021, 5:43 p.m. UTC 
As stated in commit ac3415f5c1b1 ("lib/fs: Fix and simplify make_path()"),
calling stat() before mkdir() is racey, because the entry might change in
between.

As the call to stat() seems to only check for target existence, we can
simply call mkdir() unconditionally and catch all errors but EEXIST.

Fixes: 95ae9a4870e7 ("bpf: fix mnt path when from env")
Signed-off-by: Andrea Claudi <aclaudi@redhat.com>
---
 lib/bpf_legacy.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)
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Patch

diff --git a/lib/bpf_legacy.c b/lib/bpf_legacy.c
index bc869c3f..8a03b9c2 100644
--- a/lib/bpf_legacy.c
+++ b/lib/bpf_legacy.c
@@ -510,20 +510,14 @@  static int bpf_mnt_fs(const char *target)
 
 static int bpf_mnt_check_target(const char *target)
 {
-	struct stat sb = {};
 	int ret;
 
-	ret = stat(target, &sb);
-	if (ret) {
-		ret = mkdir(target, S_IRWXU);
-		if (ret) {
-			fprintf(stderr, "mkdir %s failed: %s\n", target,
-				strerror(errno));
-			return ret;
-		}
-	}
+	ret = mkdir(target, S_IRWXU);
+	if (ret && errno != EEXIST)
+		fprintf(stderr, "mkdir %s failed: %s\n", target,
+			strerror(errno));
 
-	return 0;
+	return ret;
 }
 
 static int bpf_valid_mntpt(const char *mnt, unsigned long magic)