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Subject[PATCH -mm] Introduce strtol_check_range()

Callers (especially "store" functions for sysfs or configfs attributes)
that want to convert an input string to a number may often also want to
check for simple input sanity or allowable range. strtol10_check_range()
of netconsole does this, so extract it out into lib/vsprintf.c, make it
generic w.r.t. base, and export it to the rest of the kernel and modules.

Signed-off-by: Satyam Sharma <satyam@infradead.org>

---

[ On top of previously posted netconsole patches, and
the just-posted "Introduce U16_MAX and U32_MAX" patch. ]

[ checkpatch.pl doesn't particularly like this patch, but I wanted to be
consistent with the rest of lib/vsprintf.c and include/linux/kernel.h. ]

drivers/net/netconsole.c | 46 ++++++++++++----------------------------------
include/linux/kernel.h | 1 +
lib/vsprintf.c | 30 ++++++++++++++++++++++++++++++
3 files changed, 43 insertions(+), 34 deletions(-)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 47a8094..0992a16 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -242,34 +242,6 @@ static struct netconsole_target *to_target(struct config_item *item)
}

/*
- * Wrapper over simple_strtol (base 10) with sanity and range checking.
- * We return (signed) long only because we may want to return errors.
- * Do not use this to convert numbers that are allowed to be negative.
- */
-static long strtol10_check_range(const char *cp, long min, long max)
-{
- long ret;
- char *p = (char *) cp;
-
- WARN_ON(min < 0);
- WARN_ON(max < min);
-
- ret = simple_strtol(p, &p, 10);
-
- if (*p && (*p != '\n')) {
- printk(KERN_ERR "netconsole: invalid input\n");
- return -EINVAL;
- }
- if ((ret < min) || (ret > max)) {
- printk(KERN_ERR "netconsole: input %ld must be between "
- "%ld and %ld\n", ret, min, max);
- return -EINVAL;
- }
-
- return ret;
-}
-
-/*
* Attribute operations for netconsole_target.
*/

@@ -335,9 +307,11 @@ static ssize_t store_enabled(struct netconsole_target *nt,
int err;
long enabled;

- enabled = strtol10_check_range(buf, 0, 1);
- if (enabled < 0)
+ enabled = strtol_check_range(buf, 0, 1, 10);
+ if (enabled < 0) {
+ printk(KERN_ERR "netconsole: invalid input\n");
return enabled;
+ }

if (enabled) { /* 1 */

@@ -398,9 +372,11 @@ static ssize_t store_local_port(struct netconsole_target *nt,
return -EINVAL;
}

- local_port = strtol10_check_range(buf, 0, U16_MAX);
- if (local_port < 0)
+ local_port = strtol_check_range(buf, 0, U16_MAX, 10);
+ if (local_port < 0) {
+ printk(KERN_ERR "netconsole: invalid input\n");
return local_port;
+ }

nt->np.local_port = local_port;

@@ -420,9 +396,11 @@ static ssize_t store_remote_port(struct netconsole_target *nt,
return -EINVAL;
}

- remote_port = strtol10_check_range(buf, 0, U16_MAX);
- if (remote_port < 0)
+ remote_port = strtol_check_range(buf, 0, U16_MAX, 10);
+ if (remote_port < 0) {
+ printk(KERN_ERR "netconsole: invalid input\n");
return remote_port;
+ }

nt->np.remote_port = remote_port;

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index e9221de..ced5c1b 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -121,6 +121,7 @@ extern unsigned long simple_strtoul(const char *,char **,unsigned int);
extern long simple_strtol(const char *,char **,unsigned int);
extern unsigned long long simple_strtoull(const char *,char **,unsigned int);
extern long long simple_strtoll(const char *,char **,unsigned int);
+extern long strtol_check_range(const char *,long,long,unsigned int);
extern int sprintf(char * buf, const char * fmt, ...)
__attribute__ ((format (printf, 2, 3)));
extern int vsprintf(char *buf, const char *, va_list)
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 6b6734d..7ce8736 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -126,6 +126,36 @@ long long simple_strtoll(const char *cp,char **endp,unsigned int base)
return simple_strtoull(cp,endp,base);
}

+/**
+ * strtol_check_range - wrapper over simple_strtol with input and range checking
+ * @cp: The start of the string
+ * @min: Minimum value allowed
+ * @max: Maximum value allowed
+ * @base: The number base to use
+ *
+ * We return (signed) long only because we may want to return errors.
+ * Do not use this to convert numbers that are allowed to be negative.
+ */
+long strtol_check_range(const char *cp, long min, long max, unsigned int base)
+{
+ long ret;
+ char *p = (char *) cp;
+
+ WARN_ON(min < 0);
+ WARN_ON(max < min);
+
+ ret = simple_strtol(p, &p, base);
+
+ if (*p && (*p != '\n'))
+ return -EINVAL;
+ if ((ret < min) || (ret > max))
+ return -EINVAL;
+
+ return ret;
+}
+
+EXPORT_SYMBOL(strtol_check_range);
+
static int skip_atoi(const char **s)
{
int i=0;
-
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