From: Jessica Yu <jeyu@kernel.org>
To: Masahiro Yamada <masahiroy@kernel.org>
Cc: Matthias Maennich <maennich@google.com>,
Joe Perches <joe@perches.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/2] modpost: rework and consolidate logging interface
Date: Tue, 3 Mar 2020 15:57:36 +0100 [thread overview]
Message-ID: <20200303145736.GA16460@linux-8ccs> (raw)
In-Reply-To: <CAK7LNAQZAgobbTTTpLKNActYCYP7UdVgdE-Oz+pvvRxsxd_uaw@mail.gmail.com>
+++ Masahiro Yamada [03/03/20 23:42 +0900]:
>On Wed, Feb 26, 2020 at 11:26 PM Jessica Yu <jeyu@kernel.org> wrote:
>>
>> Rework modpost's logging interface by consolidating merror(), warn(),
>> and fatal() to use a single function, modpost_log(). Introduce different
>> logging levels (WARN, ERROR, FATAL) as well as a conditional warn
>> (warn_unless()). The conditional warn is useful in determining whether
>> to use merror() or warn() based on a condition. This reduces code
>> duplication overall.
>>
>> Signed-off-by: Jessica Yu <jeyu@kernel.org>
>> ---
>> v2:
>> - modpost_log: initialize level to ""
>> - remove parens () from case labels
>>
>> scripts/mod/modpost.c | 69 +++++++++++++++++++++++----------------------------
>> scripts/mod/modpost.h | 22 +++++++++++++---
>> 2 files changed, 50 insertions(+), 41 deletions(-)
>>
>> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
>> index 7edfdb2f4497..3201a2ac5cc4 100644
>> --- a/scripts/mod/modpost.c
>> +++ b/scripts/mod/modpost.c
>> @@ -51,41 +51,37 @@ enum export {
>>
>> #define MODULE_NAME_LEN (64 - sizeof(Elf_Addr))
>>
>> -#define PRINTF __attribute__ ((format (printf, 1, 2)))
>> +#define PRINTF __attribute__ ((format (printf, 2, 3)))
>>
>> -PRINTF void fatal(const char *fmt, ...)
>> +PRINTF void modpost_log(enum loglevel loglevel, const char *fmt, ...)
>> {
>> + char *level = "";
>
>
>You can add 'const'.
>
>
> const char *level = "";
>
>
>
>> va_list arglist;
>>
>> - fprintf(stderr, "FATAL: ");
>> -
>> - va_start(arglist, fmt);
>> - vfprintf(stderr, fmt, arglist);
>> - va_end(arglist);
>> -
>> - exit(1);
>> -}
>> -
>> -PRINTF void warn(const char *fmt, ...)
>> -{
>> - va_list arglist;
>> + switch(loglevel) {
>> + case LOG_WARN:
>> + level = "WARNING: ";
>> + break;
>> + case LOG_ERROR:
>> + level = "ERROR: ";
>> + break;
>> + case LOG_FATAL:
>> + level = "FATAL: ";
>> + break;
>> + default: /* invalid loglevel, ignore */
>> + break;
>> + }
>>
>> - fprintf(stderr, "WARNING: ");
>> + fprintf(stderr, level);
>
>
>
>If I apply this patch, I see this warning:
>
>scripts/mod/modpost.c: In function ‘modpost_log’:
>scripts/mod/modpost.c:77:2: warning: format not a string literal and
>no format arguments [-Wformat-security]
> fprintf(stderr, level);
> ^~~~~~~
>
>
>Please write like this:
>
>
> fprintf(stderr, "%s", level);
>
>
>
>
>Or, you can delete 'level', then write
>string literals directly in fprintf().
>
>
>switch(loglevel) {
>case LOG_WARN:
> fprintf(stderr, "WARNING: ");
> break;
>case LOG_ERROR:
> fprintf(stderr, "ERROR: ");
> break;
>case LOG_FATAL:
> fprintf(stderr, "FATAL: ");
> break;
>}
>
>
>
>
>> + fprintf(stderr, "modpost: ");
>>
>> va_start(arglist, fmt);
>> vfprintf(stderr, fmt, arglist);
>> va_end(arglist);
>> -}
>>
>
><snip>
>
>> diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h
>> index 64a82d2d85f6..631d07714f7a 100644
>> --- a/scripts/mod/modpost.h
>> +++ b/scripts/mod/modpost.h
>> @@ -198,6 +198,22 @@ void *grab_file(const char *filename, unsigned long *size);
>> char* get_next_line(unsigned long *pos, void *file, unsigned long size);
>> void release_file(void *file, unsigned long size);
>>
>> -void fatal(const char *fmt, ...);
>> -void warn(const char *fmt, ...);
>> -void merror(const char *fmt, ...);
>> +enum loglevel {
>> + LOG_WARN,
>> + LOG_ERROR,
>> + LOG_FATAL
>> +};
>> +
>> +void modpost_log(enum loglevel loglevel, const char *fmt, ...);
>> +
>> +#define warn(fmt, args...) modpost_log(LOG_WARN, fmt, ##args)
>> +#define merror(fmt, args...) modpost_log(LOG_ERROR, fmt, ##args)
>> +#define fatal(fmt, args...) modpost_log(LOG_FATAL, fmt, ##args)
>> +/* Warn unless condition is true, then use merror() */
>> +#define warn_unless(condition, fmt, args...) \
>> +do { \
>> + if (condition) \
>> + merror(fmt, ##args); \
>> + else \
>> + warn(fmt, ##args); \
>> +} while (0)
>
>
>Hmm, warn_unless() is not intuitive naming...
>
>You could use modpost_log() directly in C code,
>what do you think?
>
>
> modpost_log(allow_missing_ns_imports ? LOG_WARN : LOG_ERROR,
> "module %s uses symbol %s from namespace %s,
>but does not import it.\n",
> basename, exp->name, exp->namespace);
Yeah, I wasn't sure if I should expose modpost_log() and call it
directly, so I wrapped it in warn_unless(). But I think it's not a big
deal, so I'll just change it to a direct call. Thank you for the review!
Jessica
next prev parent reply other threads:[~2020-03-03 14:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-26 14:26 [PATCH v2 1/2] modpost: rework and consolidate logging interface Jessica Yu
2020-02-26 14:26 ` [PATCH v2 2/2] modpost: return error if module is missing ns imports and MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n Jessica Yu
2020-03-03 15:21 ` Masahiro Yamada
2020-03-03 14:42 ` [PATCH v2 1/2] modpost: rework and consolidate logging interface Masahiro Yamada
2020-03-03 14:57 ` Jessica Yu [this message]
2020-03-04 11:14 ` Matthias Maennich
2020-03-03 15:23 ` Masahiro Yamada
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200303145736.GA16460@linux-8ccs \
--to=jeyu@kernel.org \
--cc=joe@perches.com \
--cc=linux-kernel@vger.kernel.org \
--cc=maennich@google.com \
--cc=masahiroy@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).