| Message ID | 1391546631-7715-2-git-send-email-sebastian.capella@linaro.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tue, 4 Feb 2014 12:43:49 -0800 Sebastian Capella <sebastian.capella@linaro.org> wrote: > kstrdup_trimnl creates a duplicate of the passed in > null-terminated string. If a trailing newline is found, it > is removed before duplicating. This is useful for strings > coming from sysfs that often include trailing whitespace due to > user input. hm, why? I doubt if any caller of this wants to retain leading and/or trailing spaces and/or tabs. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 05 Feb 2014 14:55:52 -0800 Sebastian Capella <sebastian.capella@linaro.org> wrote: > Quoting Andrew Morton (2014-02-05 13:50:52) > > On Tue, 4 Feb 2014 12:43:49 -0800 Sebastian Capella <sebastian.capella@linaro.org> wrote: > > > > > kstrdup_trimnl creates a duplicate of the passed in > > > null-terminated string. If a trailing newline is found, it > > > is removed before duplicating. This is useful for strings > > > coming from sysfs that often include trailing whitespace due to > > > user input. > > > > hm, why? I doubt if any caller of this wants to retain leading and/or > > trailing spaces and/or tabs. > > Hi Andrew, > > I agree the common case doesn't usually need leading or trailing whitespace. > > Pavel and others pointed out that a valid filename could contain > newlines/whitespace at any position. The number of cases in which we provide the kernel with a filename via sysfs will be very very small, or zero. If we can go through existing code and find at least a few sites which can usefully employ kstrdup_trimnl() then fine, we have evidence. But I doubt if we can do that? -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/linux/string.h b/include/linux/string.h index ac889c5..e7ec8c0 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -114,6 +114,7 @@ void *memchr_inv(const void *s, int c, size_t n); extern char *kstrdup(const char *s, gfp_t gfp); extern char *kstrndup(const char *s, size_t len, gfp_t gfp); +extern char *kstrdup_trimnl(const char *s, gfp_t gfp); extern void *kmemdup(const void *src, size_t len, gfp_t gfp); extern char **argv_split(gfp_t gfp, const char *str, int *argcp); diff --git a/mm/util.c b/mm/util.c index 808f375..0bab867 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1,6 +1,7 @@ #include <linux/mm.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/ctype.h> #include <linux/export.h> #include <linux/err.h> #include <linux/sched.h> @@ -63,6 +64,34 @@ char *kstrndup(const char *s, size_t max, gfp_t gfp) EXPORT_SYMBOL(kstrndup); /** + * kstrdup_trimnl - Copy a %NUL terminated string, removing one trailing + * newline if present. + * @s: the string to duplicate + * @gfp: the GFP mask used in the kmalloc() call when allocating memory + * + * Returns an address, which the caller must kfree, containing + * a duplicate of the passed string with a single trailing newline + * removed if present. + */ +char *kstrdup_trimnl(const char *s, gfp_t gfp) +{ + char *buf; + size_t len = strlen(s); + if (len >= 1 && s[len - 1] == '\n') + len--; + + buf = kmalloc_track_caller(len + 1, gfp); + if (!buf) + return NULL; + + memcpy(buf, s, len); + buf[len] = '\0'; + + return buf; +} +EXPORT_SYMBOL(kstrdup_trimnl); + +/** * kmemdup - duplicate region of memory * * @src: memory region to duplicate
kstrdup_trimnl creates a duplicate of the passed in null-terminated string. If a trailing newline is found, it is removed before duplicating. This is useful for strings coming from sysfs that often include trailing whitespace due to user input. Signed-off-by: Sebastian Capella <sebastian.capella@linaro.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Rik van Riel <riel@redhat.com> (commit_signer:5/10=50%) Cc: Michel Lespinasse <walken@google.com> Cc: Shaohua Li <shli@kernel.org> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Joe Perches <joe@perches.com> Cc: David Rientjes <rientjes@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> --- include/linux/string.h | 1 + mm/util.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+)