[Xen-devel] [patch 01/44] add kstrndup

[Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>]

Add a kstrndup function, modelled on strndup.  Like strndup this
returns a string copied into its own allocated memory, but it copies
no more than the specified number of bytes from the source.

Remove private strndup() from irda code.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Cc: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Cc: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxx>
Cc: Panagiotis Issaris <takis@xxxxxxxxxxx>
Cc: Rene Scharfe <rene.scharfe@xxxxxxxxxxxxxx>

---
 include/linux/string.h  |    1 +
 mm/util.c               |   28 +++++++++++++++++++++++++---
 net/irda/irias_object.c |   43 +++++--------------------------------------
 3 files changed, 31 insertions(+), 41 deletions(-)

===================================================================
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -105,6 +105,7 @@ extern void * memchr(const void *,int,__
 #endif
 
 extern char *kstrdup(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);
 
 #ifdef __cplusplus
===================================================================
--- a/mm/util.c
+++ b/mm/util.c
@@ -18,9 +18,8 @@ void *__kzalloc(size_t size, gfp_t flags
 }
 EXPORT_SYMBOL(__kzalloc);
 
-/*
+/**
  * kstrdup - allocate space for and copy an existing string
- *
  * @s: the string to duplicate
  * @gfp: the GFP mask used in the kmalloc() call when allocating memory
  */
@@ -39,6 +38,30 @@ char *kstrdup(const char *s, gfp_t gfp)
        return buf;
 }
 EXPORT_SYMBOL(kstrdup);
+
+/**
+ * kstrndup - allocate space for and copy an existing string
+ * @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
+ */
+char *kstrndup(const char *s, size_t max, gfp_t gfp)
+{
+       size_t len;
+       char *buf;
+
+       if (!s)
+               return NULL;
+
+       len = strnlen(s, max);
+       buf = kmalloc_track_caller(len+1, gfp);
+       if (buf) {
+               memcpy(buf, s, len);
+               buf[len] = '\0';
+       }
+       return buf;
+}
+EXPORT_SYMBOL(kstrndup);
 
 /**
  * kmemdup - duplicate region of memory
@@ -60,7 +83,6 @@ EXPORT_SYMBOL(kmemdup);
 
 /*
  * strndup_user - duplicate an existing string from user space
- *
  * @s: The string to duplicate
  * @n: Maximum number of bytes to copy, including the trailing NUL.
  */
===================================================================
--- a/net/irda/irias_object.c
+++ b/net/irda/irias_object.c
@@ -36,39 +36,6 @@ hashbin_t *irias_objects;
  */
 struct ias_value irias_missing = { IAS_MISSING, 0, 0, 0, {0}};
 
-/*
- * Function strndup (str, max)
- *
- *    My own kernel version of strndup!
- *
- * Faster, check boundary... Jean II
- */
-static char *strndup(char *str, size_t max)
-{
-       char *new_str;
-       int len;
-
-       /* Check string */
-       if (str == NULL)
-               return NULL;
-       /* Check length, truncate */
-       len = strlen(str);
-       if(len > max)
-               len = max;
-
-       /* Allocate new string */
-       new_str = kmalloc(len + 1, GFP_ATOMIC);
-       if (new_str == NULL) {
-               IRDA_WARNING("%s: Unable to kmalloc!\n", __FUNCTION__);
-               return NULL;
-       }
-
-       /* Copy and truncate */
-       memcpy(new_str, str, len);
-       new_str[len] = '\0';
-
-       return new_str;
-}
 
 /*
  * Function ias_new_object (name, id)
@@ -90,7 +57,7 @@ struct ias_object *irias_new_object( cha
        }
 
        obj->magic = IAS_OBJECT_MAGIC;
-       obj->name = strndup(name, IAS_MAX_CLASSNAME);
+       obj->name = kstrndup(name, IAS_MAX_CLASSNAME, GFP_ATOMIC);
        if (!obj->name) {
                IRDA_WARNING("%s(), Unable to allocate name!\n",
                             __FUNCTION__);
@@ -360,7 +327,7 @@ void irias_add_integer_attrib(struct ias
        }
 
        attrib->magic = IAS_ATTRIB_MAGIC;
-       attrib->name = strndup(name, IAS_MAX_ATTRIBNAME);
+       attrib->name = kstrndup(name, IAS_MAX_ATTRIBNAME, GFP_ATOMIC);
 
        /* Insert value */
        attrib->value = irias_new_integer_value(value);
@@ -404,7 +371,7 @@ void irias_add_octseq_attrib(struct ias_
        }
 
        attrib->magic = IAS_ATTRIB_MAGIC;
-       attrib->name = strndup(name, IAS_MAX_ATTRIBNAME);
+       attrib->name = kstrndup(name, IAS_MAX_ATTRIBNAME, GFP_ATOMIC);
 
        attrib->value = irias_new_octseq_value( octets, len);
        if (!attrib->name || !attrib->value) {
@@ -446,7 +413,7 @@ void irias_add_string_attrib(struct ias_
        }
 
        attrib->magic = IAS_ATTRIB_MAGIC;
-       attrib->name = strndup(name, IAS_MAX_ATTRIBNAME);
+       attrib->name = kstrndup(name, IAS_MAX_ATTRIBNAME, GFP_ATOMIC);
 
        attrib->value = irias_new_string_value(value);
        if (!attrib->name || !attrib->value) {
@@ -506,7 +473,7 @@ struct ias_value *irias_new_string_value
 
        value->type = IAS_STRING;
        value->charset = CS_ASCII;
-       value->t.string = strndup(string, IAS_MAX_STRING);
+       value->t.string = kstrndup(string, IAS_MAX_STRING, GFP_ATOMIC);
        if (!value->t.string) {
                IRDA_WARNING("%s: Unable to kmalloc!\n", __FUNCTION__);
                kfree(value);

-- 


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