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Date: Mon, 10 Oct 2011 00:03:37 +0200
From: Michal Schmidt <mschmidt@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Rusty Russell <rusty@...tcorp.com.au>,
Randy Dunlap <rdunlap@...otime.net>,
Michal Schmidt <mschmidt@...hat.com>
Subject: [PATCH] params: make dashes and underscores in parameter names truly equal
The user may use "foo-bar" for a kernel parameter defined as "foo_bar".
Make sure it works the other way around too.
Apply the equality of dashes and underscores on early_params and __setup
params as well.
The example given in Documentation/kernel-parameters.txt indicates that
this is the intended behaviour.
With the patch the kernel accepts "log-buf-len=1M" as expected.
https://bugzilla.redhat.com/show_bug.cgi?id=744545
Signed-off-by: Michal Schmidt <mschmidt@...hat.com>
---
include/linux/moduleparam.h | 20 ++++++++++++++++++++
init/main.c | 4 ++--
kernel/params.c | 34 +++++++++++++++++++++++++++-------
3 files changed, 49 insertions(+), 9 deletions(-)
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index 56bda92..609f89c 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -267,6 +267,26 @@ static inline void __kernel_param_unlock(void)
.str = &__param_string_##name, 0, perm); \
__MODULE_PARM_TYPE(name, "string")
+/**
+ * parameq - checks if two parameter names match
+ * @name1: parameter name 1
+ * @name2: parameter name 2
+ *
+ * Returns true if the two parameter names are equal.
+ * Dashes (-) are considered equal to underscores (_).
+ */
+extern bool parameq(const char *name1, const char *name2);
+
+/**
+ * parameqn - checks if two parameter names match
+ * @name1: parameter name 1
+ * @name2: parameter name 2
+ * @n: the maximum length to compare
+ *
+ * Similar to parameq(), except it compares at most @n characters.
+ */
+extern bool parameqn(const char *name1, const char *name2, size_t n);
+
/* Called on module insert or kernel boot */
extern int parse_args(const char *name,
char *args,
diff --git a/init/main.c b/init/main.c
index 03b408d..63f5f6f 100644
--- a/init/main.c
+++ b/init/main.c
@@ -163,7 +163,7 @@ static int __init obsolete_checksetup(char *line)
p = __setup_start;
do {
int n = strlen(p->str);
- if (!strncmp(line, p->str, n)) {
+ if (parameqn(line, p->str, n)) {
if (p->early) {
/* Already done in parse_early_param?
* (Needs exact match on param part).
@@ -392,7 +392,7 @@ static int __init do_early_param(char *param, char *val)
const struct obs_kernel_param *p;
for (p = __setup_start; p < __setup_end; p++) {
- if ((p->early && strcmp(param, p->str) == 0) ||
+ if ((p->early && parameq(param, p->str)) ||
(strcmp(param, "console") == 0 &&
strcmp(p->str, "earlycon") == 0)
) {
diff --git a/kernel/params.c b/kernel/params.c
index 1d1c01b..aa8933c 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -67,20 +67,40 @@ static void maybe_kfree_parameter(void *param)
}
}
-static inline char dash2underscore(char c)
+static char dash2underscore(char c)
{
if (c == '-')
return '_';
return c;
}
-static inline int parameq(const char *input, const char *paramname)
+bool parameq(const char *name1, const char *name2)
{
- unsigned int i;
- for (i = 0; dash2underscore(input[i]) == paramname[i]; i++)
- if (input[i] == '\0')
- return 1;
- return 0;
+ char c1, c2;
+ while (1) {
+ c1 = dash2underscore(*name1++);
+ c2 = dash2underscore(*name2++);
+ if (c1 != c2)
+ return false;
+ if (c1 == '\0')
+ break;
+ }
+ return true;
+}
+
+bool parameqn(const char *name1, const char *name2, size_t n)
+{
+ char c1, c2;
+ while (n) {
+ c1 = dash2underscore(*name1++);
+ c2 = dash2underscore(*name2++);
+ if (c1 != c2)
+ return false;
+ if (c1 == '\0')
+ break;
+ n--;
+ }
+ return true;
}
static int parse_one(char *param,
--
1.7.4.4
--
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