Blame SOURCES/0127-bpf-minor-cleanups-for-bpf_trace_pipe.patch

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From edf0ae950c5b9d3c5eed29a40f5669cf657995e6 Mon Sep 17 00:00:00 2001
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From: Andrea Claudi <aclaudi@redhat.com>
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Date: Tue, 30 Apr 2019 15:43:03 +0200
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Subject: [PATCH] bpf: minor cleanups for bpf_trace_pipe
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1465646
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Upstream Status: iproute2.git commit 1b736dc469dca
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commit 1b736dc469dcabd4180848a1f1b3d1fef2b84dbc
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Author: Daniel Borkmann <daniel@iogearbox.net>
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Date:   Tue Sep 5 02:24:31 2017 +0200
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    bpf: minor cleanups for bpf_trace_pipe
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    Just minor nits, e.g. no need to fflush() and instead of returning
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    right away, just break and close the fd.
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    Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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---
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 lib/bpf.c | 19 +++++++++----------
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 1 file changed, 9 insertions(+), 10 deletions(-)
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diff --git a/lib/bpf.c b/lib/bpf.c
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index e072cba214067..f0e6c6fb732ee 100644
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--- a/lib/bpf.c
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+++ b/lib/bpf.c
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@@ -461,9 +461,9 @@ int bpf_trace_pipe(void)
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 		"/trace",
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 		0,
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 	};
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+	int fd_in, fd_out = STDERR_FILENO;
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 	char tpipe[PATH_MAX];
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 	const char *mnt;
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-	int fd;
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 	mnt = bpf_find_mntpt("tracefs", TRACEFS_MAGIC, tracefs_mnt,
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 			     sizeof(tracefs_mnt), tracefs_known_mnts);
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@@ -474,8 +474,8 @@ int bpf_trace_pipe(void)
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 	snprintf(tpipe, sizeof(tpipe), "%s/trace_pipe", mnt);
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-	fd = open(tpipe, O_RDONLY);
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-	if (fd < 0)
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+	fd_in = open(tpipe, O_RDONLY);
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+	if (fd_in < 0)
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 		return -1;
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 	fprintf(stderr, "Running! Hang up with ^C!\n\n");
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@@ -483,15 +483,14 @@ int bpf_trace_pipe(void)
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 		static char buff[4096];
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 		ssize_t ret;
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-		ret = read(fd, buff, sizeof(buff) - 1);
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-		if (ret > 0) {
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-			if (write(STDERR_FILENO, buff, ret) != ret)
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-				return -1;
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-			fflush(stderr);
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-		}
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+		ret = read(fd_in, buff, sizeof(buff));
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+		if (ret > 0 && write(fd_out, buff, ret) == ret)
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+			continue;
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+		break;
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 	}
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-	return 0;
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+	close(fd_in);
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+	return -1;
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 }
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 static int bpf_gen_global(const char *bpf_sub_dir)
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-- 
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2.20.1
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