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[nf-next,1/5] networking: Introduce nla_strdup()

Message ID 20170720152450.27693-2-phil@nwl.cc
State Changes Requested
Delegated to: Pablo Neira
Headers show

Commit Message

Phil Sutter July 20, 2017, 3:24 p.m. UTC 
This is similar to strdup() for netlink string attributes.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 include/net/netlink.h |  1 +
 lib/nlattr.c          | 24 ++++++++++++++++++++++++
 2 files changed, 25 insertions(+)
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Patch

diff --git a/include/net/netlink.h b/include/net/netlink.h
index 01709172b3d38..5c1fc1d4b0969 100644
--- a/include/net/netlink.h
+++ b/include/net/netlink.h
@@ -247,6 +247,7 @@  int nla_parse(struct nlattr **tb, int maxtype, const struct nlattr *head,
 int nla_policy_len(const struct nla_policy *, int);
 struct nlattr *nla_find(const struct nlattr *head, int len, int attrtype);
 size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize);
+char *nla_strdup(const struct nlattr *nla, gfp_t flags);
 int nla_memcpy(void *dest, const struct nlattr *src, int count);
 int nla_memcmp(const struct nlattr *nla, const void *data, size_t size);
 int nla_strcmp(const struct nlattr *nla, const char *str);
diff --git a/lib/nlattr.c b/lib/nlattr.c
index a7e0b16078dff..af8716fb8a3bf 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -272,6 +272,30 @@  size_t nla_strlcpy(char *dst, const struct nlattr *nla, size_t dstsize)
 EXPORT_SYMBOL(nla_strlcpy);
 
 /**
+ * nla_strdup - Copy string attribute payload into a newly allocated buffer
+ * @nla: attribute to copy the string from
+ * @flags: the type of memory to allocate (see kmalloc).
+ *
+ * Returns a pointer to the allocated buffer or NULL on error.
+ */
+char *nla_strdup(const struct nlattr *nla, gfp_t flags)
+{
+	size_t srclen = nla_len(nla);
+	char *src = nla_data(nla), *dst;
+
+	if (srclen > 0 && src[srclen - 1] == '\0')
+		srclen--;
+
+	dst = kmalloc(srclen + 1, flags);
+	if (dst != NULL) {
+		memcpy(dst, src, srclen);
+		dst[srclen] = '\0';
+	}
+	return dst;
+}
+EXPORT_SYMBOL(nla_strdup);
+
+/**
  * nla_memcpy - Copy a netlink attribute into another memory area
  * @dest: where to copy to memcpy
  * @src: netlink attribute to copy from