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[bpf-next,3/5] libbpf: Add bpf_vprintk convenience macro

Message ID 20210821025837.1614098-4-davemarchevsky@fb.com
State New
Headers show
Series bpf: implement variadic printk helper | expand

Commit Message

Dave Marchevsky Aug. 21, 2021, 2:58 a.m. UTC 
bpf_vprintk functions similarly to BPF_SEQ_PRINTF and BPF_SNPRINTF
macros elsewhere in the file - it allows use of bpf_trace_vprintk
without manual conversion of varargs to u64 array.

Like the bpf_printk macro, bpf_vprintk is meant to be the main interface
to the bpf_trace_vprintk helper and thus is uncapitalized.

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
---
 tools/lib/bpf/bpf_helpers.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
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Patch

diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h
index b9987c3efa3c..43c8115956c3 100644
--- a/tools/lib/bpf/bpf_helpers.h
+++ b/tools/lib/bpf/bpf_helpers.h
@@ -224,4 +224,22 @@  enum libbpf_tristate {
 		     ___param, sizeof(___param));		\
 })
 
+/*
+ * bpf_vprintk wraps the bpf_trace_printk helper with variadic arguments
+ * instead of an array of u64.
+ */
+#define bpf_vprintk(fmt, args...)				\
+({								\
+	static const char ___fmt[] = fmt;			\
+	unsigned long long ___param[___bpf_narg(args)];		\
+								\
+	_Pragma("GCC diagnostic push")				\
+	_Pragma("GCC diagnostic ignored \"-Wint-conversion\"")	\
+	___bpf_fill(___param, args);				\
+	_Pragma("GCC diagnostic pop")				\
+								\
+	bpf_trace_vprintk(___fmt, sizeof(___fmt),		\
+		     ___param, sizeof(___param));		\
+})
+
 #endif