[PATCH 1/2] modpost: rework and consolidate logging interface

Jessica Yu
2020-02-25T17:35:34Z

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>
---
Hi,

This patch was added in response to the code duplication comments in the
first version of "modpost: return error if module is missing ns imports and
MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS=n" [1]

[1] See 20200214143709.6490-1-jeyu@kernel.org

scripts/mod/modpost.c | 69 ++++++++++++++++++++++++---------------------------
scripts/mod/modpost.h | 22 +++++++++++++---
2 files changed, 51 insertions(+), 40 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 7edfdb2f4497..e2805fbeb99f 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -51,41 +51,39 @@ 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 = NULL;
va_list arglist;

- fprintf(stderr, "FATAL: ");
+ 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;
+ }

- va_start(arglist, fmt);
- vfprintf(stderr, fmt, arglist);
- va_end(arglist);
+ if (level)
+ fprintf(stderr, level);

- exit(1);
-}
-
-PRINTF void warn(const char *fmt, ...)
-{
- va_list arglist;
-
- fprintf(stderr, "WARNING: ");
+ fprintf(stderr, "modpost: ");

va_start(arglist, fmt);
vfprintf(stderr, fmt, arglist);
va_end(arglist);
-}
-
-PRINTF void merror(const char *fmt, ...)
-{
- va_list arglist;

- fprintf(stderr, "ERROR: ");
+ if (loglevel == LOG_FATAL)
+ exit(1);

- va_start(arglist, fmt);
- vfprintf(stderr, fmt, arglist);
- va_end(arglist);
}

static inline bool strends(const char *str, const char *postfix)
@@ -113,7 +111,7 @@ static int is_vmlinux(const char *modname)
void *do_nofail(void *ptr, const char *expr)
{
if (!ptr)
- fatal("modpost: Memory allocation failure: %s.\n", expr);
+ fatal("Memory allocation failure: %s.\n", expr);

return ptr;
}
@@ -2021,7 +2019,7 @@ static void read_symbols(const char *modname)

license = get_modinfo(&info, "license");
if (!license && !is_vmlinux(modname))
- warn("modpost: missing MODULE_LICENSE() in %s\n"
+ warn("missing MODULE_LICENSE() in %s\n"
"see include/linux/module.h for "
"more information\n", modname);
while (license) {
@@ -2152,15 +2150,15 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)

switch (exp) {
case export_gpl:
- fatal("modpost: GPL-incompatible module %s%s "
+ fatal("GPL-incompatible module %s%s "
"uses GPL-only symbol '%s'\n", m, e, s);
break;
case export_unused_gpl:
- fatal("modpost: GPL-incompatible module %s%s "
+ fatal("GPL-incompatible module %s%s "
"uses GPL-only symbol marked UNUSED '%s'\n", m, e, s);
break;
case export_gpl_future:
- warn("modpost: GPL-incompatible module %s%s "
+ warn("GPL-incompatible module %s%s "
"uses future GPL-only symbol '%s'\n", m, e, s);
break;
case export_plain:
@@ -2178,7 +2176,7 @@ static void check_for_unused(enum export exp, const char *m, const char *s)
switch (exp) {
case export_unused:
case export_unused_gpl:
- warn("modpost: module %s%s "
+ warn("module %s%s "
"uses symbol '%s' marked UNUSED\n", m, e, s);
break;
default:
@@ -2197,14 +2195,11 @@ static int check_exports(struct module *mod)
exp = find_symbol(s->name);
if (!exp || exp->module == mod) {
if (have_vmlinux && !s->weak) {
- if (warn_unresolved) {
- warn("\"%s\" [%s.ko] undefined!\n",
- s->name, mod->name);
- } else {
- merror("\"%s\" [%s.ko] undefined!\n",
- s->name, mod->name);
+ warn_unless(!warn_unresolved,
+ "\"%s\" [%s.ko] undefined!\n",
+ s->name, mod->name);
+ if (!warn_unresolved)
err = 1;
- }
}
continue;
}
@@ -2653,7 +2648,7 @@ int main(int argc, char **argv)
if (dump_write)
write_dump(dump_write);
if (sec_mismatch_count && sec_mismatch_fatal)
- fatal("modpost: Section mismatches detected.\n"
+ fatal("Section mismatches detected.\n"
"Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.\n");
for (n = 0; n < SYMBOL_HASH_SIZE; n++) {
struct symbol *s;
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)
--
2.16.4