Thread-safe error handling

In order for the interface to become more thread safe, the error
handling was revised to no longer depend on a static errno and
error string buffer.

This patch converts all error paths to return a libnl specific
error code which can be translated to a error message using
nl_geterror(int error). The functions nl_error() and
nl_get_errno() are therefore obsolete.

This change required various sets of function prototypes to be
changed in order to return an error code, the most prominent
are:

    struct nl_cache *foo_alloc_cache(...);
changed to:
    int foo_alloc_cache(..., struct nl_cache **);

    struct nl_msg *foo_build_request(...);
changed to:
    int foo_build_request(..., struct nl_msg **);

    struct foo *foo_parse(...);
changed to:
    int foo_parse(..., struct foo **);

This pretty much only leaves trivial allocation functions to
still return a pointer object which can still return NULL to
signal out of memory.

This change is a serious API and ABI breaker, sorry!

2 files changed, 25 insertions, 34 deletions

diff --git a/lib/route/link/api.c b/lib/route/link/api.c
index afe00b1..a0e7679 100644
--- a/lib/route/link/api.c
+++ b/lib/route/link/api.c
@@ -61,10 +61,10 @@ struct rtnl_link_info_ops *rtnl_link_info_ops_lookup(const char *name)
 int rtnl_link_register_info(struct rtnl_link_info_ops *ops)
 {
 	if (ops->io_name == NULL)
-		return nl_error(EINVAL, "No name specified");
+		return -NLE_INVAL;
 
 	if (rtnl_link_info_ops_lookup(ops->io_name))
-		return nl_error(EEXIST, "Link info operations already exist");
+		return -NLE_EXIST;
 
 	NL_DBG(1, "Registered link info operations %s\n", ops->io_name);
 
@@ -83,10 +83,10 @@ int rtnl_link_unregister_info(struct rtnl_link_info_ops *ops)
 			break;
 
 	if (!t)
-		return nl_error(ENOENT, "No such link info operations");
+		return -NLE_OPNOTSUPP;
 
 	if (t->io_refcnt > 0)
-		return nl_error(EBUSY, "Info operations in use");
+		return -NLE_BUSY;
 
 	NL_DBG(1, "Unregistered link info perations %s\n", ops->io_name);
 
diff --git a/lib/route/link/vlan.c b/lib/route/link/vlan.c
index c148dca..ea5699f 100644
--- a/lib/route/link/vlan.c
+++ b/lib/route/link/vlan.c
@@ -6,7 +6,7 @@
  *	License as published by the Free Software Foundation version 2.1
  *	of the License.
  *
- * Copyright (c) 2003-2007 Thomas Graf <tgraf@suug.ch>
+ * Copyright (c) 2003-2008 Thomas Graf <tgraf@suug.ch>
  */
 
 /**
@@ -73,7 +73,7 @@ static int vlan_alloc(struct rtnl_link *link)
 	struct vlan_info *vi;
 
 	if ((vi = calloc(1, sizeof(*vi))) == NULL)
-		return nl_errno(ENOMEM);
+		return -NLE_NOMEM;
 
 	link->l_info = vi;
 
@@ -119,12 +119,11 @@ static int vlan_parse(struct rtnl_link *link, struct nlattr *data,
 
 		nla_for_each_nested(nla, tb[IFLA_VLAN_INGRESS_QOS], remaining) {
 			if (nla_len(nla) < sizeof(*map))
-				return nl_error(EINVAL, "Malformed mapping");
+				return -NLE_INVAL;
 
 			map = nla_data(nla);
 			if (map->from < 0 || map->from > VLAN_PRIO_MAX) {
-				return nl_error(EINVAL, "VLAN prio %d out of "
-						"range", map->from);
+				return -NLE_INVAL;
 			}
 
 			vi->vi_ingress_qos[map->from] = map->to;
@@ -140,7 +139,7 @@ static int vlan_parse(struct rtnl_link *link, struct nlattr *data,
 
 		nla_for_each_nested(nla, tb[IFLA_VLAN_EGRESS_QOS], remaining) {
 			if (nla_len(nla) < sizeof(*map))
-				return nl_error(EINVAL, "Malformed mapping");
+				return -NLE_INVAL;
 			i++;
 		}
 
@@ -148,7 +147,7 @@ static int vlan_parse(struct rtnl_link *link, struct nlattr *data,
 		vi->vi_egress_size = (i + 32) & ~31;
 		vi->vi_egress_qos = calloc(vi->vi_egress_size, sizeof(*map));
 		if (vi->vi_egress_qos == NULL)
-			return nl_errno(ENOMEM);
+			return -NLE_NOMEM;
 
 		i = 0;
 		nla_for_each_nested(nla, tb[IFLA_VLAN_EGRESS_QOS], remaining) {
@@ -260,7 +259,7 @@ static int vlan_clone(struct rtnl_link *dst, struct rtnl_link *src)
 	vdst->vi_egress_qos = calloc(vsrc->vi_egress_size,
 				     sizeof(struct vlan_map));
 	if (!vdst->vi_egress_qos)
-		return nl_errno(ENOMEM);
+		return -NLE_NOMEM;
 
 	memcpy(vdst->vi_egress_qos, vsrc->vi_egress_qos,
 	       vsrc->vi_egress_size * sizeof(struct vlan_map));
@@ -274,7 +273,7 @@ static int vlan_put_attrs(struct nl_msg *msg, struct rtnl_link *link)
 	struct nlattr *data;
 
 	if (!(data = nla_nest_start(msg, IFLA_INFO_DATA)))
-		return nl_errno(ENOBUFS);
+		return -NLE_MSGSIZE;
 
 	if (vi->vi_mask & VLAN_HAS_ID)
 		NLA_PUT_U16(msg, IFLA_VLAN_ID, vi->vi_vlan_id);
@@ -349,7 +348,7 @@ int rtnl_link_vlan_set_id(struct rtnl_link *link, int id)
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	vi->vi_vlan_id = id;
 	vi->vi_mask |= VLAN_HAS_ID;
@@ -362,7 +361,7 @@ int rtnl_link_vlan_get_id(struct rtnl_link *link)
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	if (vi->vi_mask & VLAN_HAS_ID)
 		return vi->vi_vlan_id;
@@ -375,7 +374,7 @@ int rtnl_link_vlan_set_flags(struct rtnl_link *link, unsigned int flags)
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	vi->vi_flags_mask |= flags;
 	vi->vi_flags |= flags;
@@ -389,7 +388,7 @@ int rtnl_link_vlan_unset_flags(struct rtnl_link *link, unsigned int flags)
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	vi->vi_flags_mask |= flags;
 	vi->vi_flags &= ~flags;
@@ -403,7 +402,7 @@ unsigned int rtnl_link_vlan_get_flags(struct rtnl_link *link)
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	return vi->vi_flags;
 }
@@ -414,11 +413,10 @@ int rtnl_link_vlan_set_ingress_map(struct rtnl_link *link, int from,
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	if (from < 0 || from > VLAN_PRIO_MAX)
-		return nl_error(EINVAL, "Invalid vlan prio 0..%d",
-			VLAN_PRIO_MAX);
+		return -NLE_INVAL;
 
 	vi->vi_ingress_qos[from] = to;
 	vi->vi_mask |= VLAN_HAS_INGRESS_QOS;
@@ -430,10 +428,8 @@ uint32_t *rtnl_link_vlan_get_ingress_map(struct rtnl_link *link)
 {
 	struct vlan_info *vi = link->l_info;
 
-	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops) {
-		nl_error(EOPNOTSUPP, "Not a VLAN link");
+	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
 		return NULL;
-	}
 
 	if (vi->vi_mask & VLAN_HAS_INGRESS_QOS)
 		return vi->vi_ingress_qos;
@@ -446,11 +442,10 @@ int rtnl_link_vlan_set_egress_map(struct rtnl_link *link, uint32_t from, int to)
 	struct vlan_info *vi = link->l_info;
 
 	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
-		return nl_error(EOPNOTSUPP, "Not a VLAN link");
+		return -NLE_OPNOTSUPP;
 
 	if (to < 0 || to > VLAN_PRIO_MAX)
-		return nl_error(EINVAL, "Invalid vlan prio 0..%d",
-			VLAN_PRIO_MAX);
+		return -NLE_INVAL;
 
 	if (vi->vi_negress >= vi->vi_egress_size) {
 		int new_size = vi->vi_egress_size + 32;
@@ -458,7 +453,7 @@ int rtnl_link_vlan_set_egress_map(struct rtnl_link *link, uint32_t from, int to)
 
 		ptr = realloc(vi->vi_egress_qos, new_size);
 		if (!ptr)
-			return nl_errno(ENOMEM);
+			return -NLE_NOMEM;
 
 		vi->vi_egress_qos = ptr;
 		vi->vi_egress_size = new_size;
@@ -477,15 +472,11 @@ struct vlan_map *rtnl_link_vlan_get_egress_map(struct rtnl_link *link,
 {
 	struct vlan_info *vi = link->l_info;
 
-	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops) {
-		nl_error(EOPNOTSUPP, "Not a VLAN link");
+	if (link->l_info_ops != &vlan_info_ops || !link->l_info_ops)
 		return NULL;
-	}
 
-	if (negress == NULL) {
-		nl_error(EINVAL, "Require pointer to store negress");
+	if (negress == NULL)
 		return NULL;
-	}
 
 	if (vi->vi_mask & VLAN_HAS_EGRESS_QOS) {
 		*negress = vi->vi_negress;