Re: [PATCH 2/2] dwarves: cus__load_files: set errno if load fails

Arnaldo Carvalho de Melo
2022-03-16T20:51:13Z

Em Wed, Mar 16, 2022 at 02:23:54PM +0100, kkourt@kkourt.io escreveu:
> From: Kornilios Kourtis <kornilios@isovalent.com>
>
> This patch improves the error seen by the user by setting errno in
> cus__load_files(). Otherwise, we get a "No such file or directory" error
> which might be confusing.
>
> Before the patch, using a bogus file:
> $ ./pahole -J ./vmlinux-5.3.18-24.102-default.debug
> pahole: ./vmlinux-5.3.18-24.102-default.debug: No such file or directory
> $ ls ./vmlinux-5.3.18-24.102-default.debug
> /home/kkourt/src/hubble-fgs/vmlinux-5.3.18-24.102-default.debug
>
> After the patch:
> $ ./pahole -J ./vmlinux-5.3.18-24.102-default.debug
> pahole: ./vmlinux-5.3.18-24.102-default.debug: Unknown error -22
>
> Which is not very helpful, but less confusing.

Humm, because you should've set errno to -err back in cus__load_files(),
with this on top of your two patches we should get the:

#define EINVAL 22 /* Invalid argument */

"Invalid argument" or so from getting.

diff --git a/dwarves.c b/dwarves.c
index 5d0b420f0110452e..89609e96c46747ce 100644
--- a/dwarves.c
+++ b/dwarves.c
@@ -2401,7 +2401,7 @@ int cus__load_files(struct cus *cus, struct conf_load *conf,
while (filenames[i] != NULL) {
int err = cus__load_file(cus, conf, filenames[i]);
if (err) {
- errno = err;
+ errno = -err;
return -++i;
}
++i;

Agreed? I'll fix it up here and apply if so.

- Arnaldo

> Signed-off-by: Kornilios Kourtis <kornilios@isovalent.com>
> ---
> dwarves.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/dwarves.c b/dwarves.c
> index 89b58ef..5d0b420 100644
> --- a/dwarves.c
> +++ b/dwarves.c
> @@ -2399,8 +2399,11 @@ int cus__load_files(struct cus *cus, struct conf_load *conf,
> int i = 0;
>
> while (filenames[i] != NULL) {
> - if (cus__load_file(cus, conf, filenames[i]))
> + int err = cus__load_file(cus, conf, filenames[i]);
> + if (err) {
> + errno = err;
> return -++i;
> + }
> ++i;
> }
>
> --
> 2.25.1

--

- Arnaldo