--btf_features is used to specify the list of requested features
for BTF encoding. However, it is not strict in rejecting requests
with unknown features; this allows us to use the same parameters
regardless of pahole version. --btf_features_strict carries out
the same encoding with the same feature set, but will fail if an
unrecognized feature is specified.
So
pahole -J --btf_features=enum64,foo
will succeed, while
pahole -J --btf_features_strict=enum64,foo
will not.
Suggested-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
---
man-pages/pahole.1 | 4 ++++
pahole.c | 20 +++++++++++++++++---
2 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/man-pages/pahole.1 b/man-pages/pahole.1
index 6148915..ea9045c 100644
--- a/man-pages/pahole.1
+++ b/man-pages/pahole.1
@@ -297,6 +297,10 @@ Encode BTF using the specified feature list, or specify 'all' for all features s
So for example, specifying \-\-btf_encode=var,enum64 will result in a BTF encoding that (as well as encoding basic BTF information) will contain variables and enum64 values.
+.TP
+.B \-\-btf_features_strict
+Identical to \-\-btf_features above, but pahole will exit if it encounters an unrecognized feature.
+
.TP
.B \-\-supported_btf_features
Show set of BTF features supported by \-\-btf_features option and exit. Useful for checking which features are supported since \-\-btf_features will not emit an error if an unrecognized feature is specified.
diff --git a/pahole.c b/pahole.c
index 816525a..e2a2440 100644
--- a/pahole.c
+++ b/pahole.c
@@ -1231,6 +1231,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version;
#define ARGP_skip_encoding_btf_inconsistent_proto 340
#define ARGP_btf_features 341
#define ARGP_supported_btf_features 342
+#define ARGP_btf_features_strict 343
/* --btf_features=feature1[,feature2,..] allows us to specify
* a list of requested BTF features or "all" to enable all features.
@@ -1288,7 +1289,7 @@ bool set_btf_features_defaults;
* Explicitly ignores unrecognized features to allow future specification
* of new opt-in features.
*/
-static void parse_btf_features(const char *features)
+static void parse_btf_features(const char *features, bool strict)
{
char *feature_list[BTF_MAX_FEATURES] = {};
char f[BTF_MAX_FEATURE_STR];
@@ -1325,6 +1326,11 @@ static void parse_btf_features(const char *features)
break;
}
}
+ if (strict && !match) {
+ fprintf(stderr, "Feature in '%s' is not supported. 'pahole --supported_btf_features' shows the list of features supported.\n",
+ features);
+ exit(EXIT_FAILURE);
+ }
}
/* switch "default-off" features on, and "default-on" features
* off; i.e. negate the default value.
@@ -1779,6 +1785,12 @@ static const struct argp_option pahole__options[] = {
.key = ARGP_supported_btf_features,
.doc = "Show list of btf_features supported by pahole and exit."
},
+ {
+ .name = "btf_features_strict",
+ .key = ARGP_btf_features_strict,
+ .arg = "FEATURE_LIST_STRICT",
+ .doc = "Specify supported BTF features in FEATURE_LIST or 'all' for all supported features. Unlike --btf_features, unrecognized features will trigger an error."
+ },
{
.name = NULL,
}
@@ -1924,7 +1936,7 @@ static error_t pahole__options_parser(int key, char *arg,
case ARGP_btf_gen_floats:
conf_load.btf_gen_floats = true; break;
case ARGP_btf_gen_all:
- parse_btf_features("all"); break;
+ parse_btf_features("all", false); break;
case ARGP_with_flexible_array:
show_with_flexible_array = true; break;
case ARGP_prettify_input_filename:
@@ -1955,9 +1967,11 @@ static error_t pahole__options_parser(int key, char *arg,
case ARGP_skip_encoding_btf_inconsistent_proto:
conf_load.skip_encoding_btf_inconsistent_proto = true; break;
case ARGP_btf_features:
- parse_btf_features(arg); break;
+ parse_btf_features(arg, false); break;
case ARGP_supported_btf_features:
show_supported_btf_features(); exit(0);
+ case ARGP_btf_features_strict:
+ parse_btf_features(arg, true); break;
default:
return ARGP_ERR_UNKNOWN;
}
--
2.31.1
