diff options
| author | David Howells <dhowells@redhat.com> | 2017-07-04 17:25:02 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-25 11:05:41 +0100 |
| commit | 5cab144f072bdae16f37a06efb0dad210c7ff7bb (patch) | |
| tree | 7df4d6b57798ff9d0e263f94fd420c3733c227d6 | |
| parent | 5fd4db305f2750418151d2d5553bfaec2956167a (diff) | |
Provide a function to create a NUL-terminated string from unterminated data
commit f35157417215ec138c920320c746fdb3e04ef1d5 upstream.
Provide a function, kmemdup_nul(), that will create a NUL-terminated string
from an unterminated character array where the length is known in advance.
This is better than kstrndup() in situations where we already know the
string length as the strnlen() in kstrndup() is superfluous.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/string.h | 1 | ||||
| -rw-r--r-- | mm/util.c | 24 |
2 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h index 26b6f6a66f83..0c88c0a1a72b 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -123,6 +123,7 @@ extern char *kstrdup(const char *s, gfp_t gfp) __malloc; extern const char *kstrdup_const(const char *s, gfp_t gfp); extern char *kstrndup(const char *s, size_t len, gfp_t gfp); extern void *kmemdup(const void *src, size_t len, gfp_t gfp); +extern char *kmemdup_nul(const char *s, size_t len, gfp_t gfp); extern char **argv_split(gfp_t gfp, const char *str, int *argcp); extern void argv_free(char **argv); diff --git a/mm/util.c b/mm/util.c index 1a41553db866..8c755d05d4e6 100644 --- a/mm/util.c +++ b/mm/util.c @@ -80,6 +80,8 @@ EXPORT_SYMBOL(kstrdup_const); * @s: the string to duplicate * @max: read at most @max chars from @s * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Note: Use kmemdup_nul() instead if the size is known exactly. */ char *kstrndup(const char *s, size_t max, gfp_t gfp) { @@ -118,6 +120,28 @@ void *kmemdup(const void *src, size_t len, gfp_t gfp) EXPORT_SYMBOL(kmemdup); /** + * kmemdup_nul - Create a NUL-terminated string from unterminated data + * @s: The data to stringify + * @len: The size of the data + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + */ +char *kmemdup_nul(const char *s, size_t len, gfp_t gfp) +{ + char *buf; + + if (!s) + return NULL; + + buf = kmalloc_track_caller(len + 1, gfp); + if (buf) { + memcpy(buf, s, len); + buf[len] = '\0'; + } + return buf; +} +EXPORT_SYMBOL(kmemdup_nul); + +/** * memdup_user - duplicate memory region from user space * * @src: source address in user space |