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[v2,bpf-next,5/5] bpftool: set errno on skeleton failures and propagate errors

Message ID 20210525035935.1461796-6-andrii@kernel.org (mailing list archive)
State Accepted
Commit 9c6c0449deb41dbe3a66ab9adfd08020bba6c43d
Delegated to: BPF
Headers show
Series libbpf: error reporting changes for v1.0 | expand


Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
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netdev/tree_selection success Clearly marked for bpf-next
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netdev/cc_maintainers warning 8 maintainers not CCed: yhs@fb.com kpsingh@kernel.org kafai@fb.com ast@kernel.org tklauser@distanz.ch yuehaibing@huawei.com songliubraving@fb.com quentin@isovalent.com
netdev/source_inline success Was 0 now: 0
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netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch fail CHECK: spaces preferred around that '%' (ctx:WxV) ERROR: spaces required around that ':' (ctx:VxW) ERROR: trailing statements should be on next line WARNING: labels should not be indented WARNING: line length of 87 exceeds 80 columns
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link

Commit Message

Andrii Nakryiko May 25, 2021, 3:59 a.m. UTC
Follow libbpf's error handling conventions and pass through errors and errno
properly. Skeleton code always returned NULL on errors (not ERR_PTR(err)), so
there are no backwards compatibility concerns. But now we also set errno
properly, so it's possible to distinguish different reasons for failure, if

Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
 tools/bpf/bpftool/gen.c | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)
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diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 13b0aa789178..1d71ff8c52fa 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -713,6 +713,7 @@  static int do_skeleton(int argc, char **argv)
 		#ifndef %2$s						    \n\
 		#define %2$s						    \n\
+		#include <errno.h>					    \n\
 		#include <stdlib.h>					    \n\
 		#include <bpf/libbpf.h>					    \n\
@@ -793,18 +794,23 @@  static int do_skeleton(int argc, char **argv)
 		%1$s__open_opts(const struct bpf_object_open_opts *opts)    \n\
 		{							    \n\
 			struct %1$s *obj;				    \n\
+			int err;					    \n\
 			obj = (struct %1$s *)calloc(1, sizeof(*obj));	    \n\
-			if (!obj)					    \n\
+			if (!obj) {					    \n\
+				errno = ENOMEM;				    \n\
 				return NULL;				    \n\
-			if (%1$s__create_skeleton(obj))			    \n\
-				goto err;				    \n\
-			if (bpf_object__open_skeleton(obj->skeleton, opts)) \n\
-				goto err;				    \n\
+			}						    \n\
+									    \n\
+			err = %1$s__create_skeleton(obj);		    \n\
+			err = err ?: bpf_object__open_skeleton(obj->skeleton, opts);\n\
+			if (err)					    \n\
+				goto err_out;				    \n\
 			return obj;					    \n\
-		err:							    \n\
+		err_out:						    \n\
 			%1$s__destroy(obj);				    \n\
+			errno = -err;					    \n\
 			return NULL;					    \n\
 		}							    \n\
@@ -824,12 +830,15 @@  static int do_skeleton(int argc, char **argv)
 		%1$s__open_and_load(void)				    \n\
 		{							    \n\
 			struct %1$s *obj;				    \n\
+			int err;					    \n\
 			obj = %1$s__open();				    \n\
 			if (!obj)					    \n\
 				return NULL;				    \n\
-			if (%1$s__load(obj)) {				    \n\
+			err = %1$s__load(obj);				    \n\
+			if (err) {					    \n\
 				%1$s__destroy(obj);			    \n\
+				errno = -err;				    \n\
 				return NULL;				    \n\
 			}						    \n\
 			return obj;					    \n\
@@ -860,7 +869,7 @@  static int do_skeleton(int argc, char **argv)
 			s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
 			if (!s)						    \n\
-				return -1;				    \n\
+				goto err;				    \n\
 			obj->skeleton = s;				    \n\
 			s->sz = sizeof(*s);				    \n\
@@ -949,7 +958,7 @@  static int do_skeleton(int argc, char **argv)
 			return 0;					    \n\
 		err:							    \n\
 			bpf_object__destroy_skeleton(s);		    \n\
-			return -1;					    \n\
+			return -ENOMEM;					    \n\
 		}							    \n\
 		#endif /* %s */						    \n\