Re: [PATCH 1/3] perf tools: Refactor out kernel symbol argument sanity checking

From: Denis Nikitin
Date: Fri Nov 05 2021 - 21:41:40 EST


On Mon, Oct 18, 2021 at 6:48 AM James Clark <james.clark@xxxxxxx> wrote:
>
> User supplied values for vmlinux and kallsyms are checked before
> continuing. Refactor this into a function so that it can be used
> elsewhere.
>
> Signed-off-by: James Clark <james.clark@xxxxxxx>
> ---
> tools/perf/builtin-report.c | 13 ++-----------
> tools/perf/util/symbol.c | 22 ++++++++++++++++++++++
> tools/perf/util/symbol.h | 2 ++
> 3 files changed, 26 insertions(+), 11 deletions(-)
>
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index a0316ce910db..8167ebfe776a 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -1378,18 +1378,9 @@ int cmd_report(int argc, const char **argv)
> if (quiet)
> perf_quiet_option();
>
> - if (symbol_conf.vmlinux_name &&
> - access(symbol_conf.vmlinux_name, R_OK)) {
> - pr_err("Invalid file: %s\n", symbol_conf.vmlinux_name);
> - ret = -EINVAL;
> - goto exit;
> - }
> - if (symbol_conf.kallsyms_name &&
> - access(symbol_conf.kallsyms_name, R_OK)) {
> - pr_err("Invalid file: %s\n", symbol_conf.kallsyms_name);
> - ret = -EINVAL;
> + ret = symbol__validate_sym_arguments();
> + if (ret)
> goto exit;
> - }
>
> if (report.inverted_callchain)
> callchain_param.order = ORDER_CALLER;
> diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
> index 0fc9a5410739..8fad1f0d41cb 100644
> --- a/tools/perf/util/symbol.c
> +++ b/tools/perf/util/symbol.c
> @@ -2630,3 +2630,25 @@ struct mem_info *mem_info__new(void)
> refcount_set(&mi->refcnt, 1);
> return mi;
> }
> +
> +/*
> + * Checks that user supplied symbol kernel files are accessible because
> + * the default mechanism for accessing elf files fails silently. i.e. if
> + * debug syms for a build ID aren't found perf carries on normally. When
> + * they are user supplied we should assume that the user doesn't want to
> + * silently fail.
> + */
> +int symbol__validate_sym_arguments(void)
> +{
> + if (symbol_conf.vmlinux_name &&
> + access(symbol_conf.vmlinux_name, R_OK)) {
> + pr_err("Invalid file: %s\n", symbol_conf.vmlinux_name);
> + return -EINVAL;
> + }
> + if (symbol_conf.kallsyms_name &&
> + access(symbol_conf.kallsyms_name, R_OK)) {
> + pr_err("Invalid file: %s\n", symbol_conf.kallsyms_name);
> + return -EINVAL;
> + }
> + return 0;
> +}
> diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
> index 954d6a049ee2..166196686f2e 100644
> --- a/tools/perf/util/symbol.h
> +++ b/tools/perf/util/symbol.h
> @@ -286,4 +286,6 @@ static inline void __mem_info__zput(struct mem_info **mi)
>
> #define mem_info__zput(mi) __mem_info__zput(&mi)
>
> +int symbol__validate_sym_arguments(void);
> +
> #endif /* __PERF_SYMBOL */
> --
> 2.28.0
>

Reviewed-by: Denis Nikitin <denik@xxxxxxxxxxxx>