Messages in this thread | | | Date | Wed, 4 Mar 2020 11:14:22 +0000 | From | Matthias Maennich <> | Subject | Re: [PATCH v2 1/2] modpost: rework and consolidate logging interface |
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On Tue, Mar 03, 2020 at 03:57:36PM +0100, Jessica Yu wrote: >+++ 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)
The only thing that bothered me a bit was the inconsistent naming with 'merror'. I know `error` is reserved, but refactoring this whole code (thanks for that!) seems like a code opportunity to clean this up. (Or is it just me?)
Cheers, Matthias
>>>+#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
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