[dpdk-dev] [PATCH] power: fix argument cannot be negative

[Daniel Mrzyglod <danielx.t.mrzyglod@intel.com>]

Fix issue reported by Coverity.
Coverity ID 13269 & 13266:

Function strerror(errno) has built strings only for non-negative errno values.
for negative values of errno it describe error as "Unknown error -errno"
to be more descriptive i put string "channel not found" taken from header.

The negative argument will be interpreted as a very large unsigned value.

In send_msg: Negative value used as argument to a function expecting
a positive value (for example, size of buffer or allocation)

Fixes: 445c6528b55f ("power: common interface for guest and host")

Signed-off-by: Daniel Mrzyglod <danielx.t.mrzyglod@intel.com>
---
 lib/librte_power/guest_channel.c    | 3 ++-
 lib/librte_power/rte_power_kvm_vm.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/librte_power/guest_channel.c b/lib/librte_power/guest_channel.c
index d6b6d0a..c0d23d8 100644
--- a/lib/librte_power/guest_channel.c
+++ b/lib/librte_power/guest_channel.c
@@ -104,7 +104,8 @@ guest_channel_host_connect(const char *path, unsigned lcore_id)
 	ret = guest_channel_send_msg(&pkt, lcore_id);
 	if (ret != 0) {
 		RTE_LOG(ERR, GUEST_CHANNEL, "Error on channel '%s' communications "
-				"test: %s\n", fd_path, strerror(ret));
+				"test: %s\n", fd_path, ret > 0 ? strerror(ret) :
+						"channel not connected");
 		goto error;
 	}
 	RTE_LOG(INFO, GUEST_CHANNEL, "Channel '%s' is now connected\n", fd_path);
diff --git a/lib/librte_power/rte_power_kvm_vm.c b/lib/librte_power/rte_power_kvm_vm.c
index 7bb2774..5d53e6a 100644
--- a/lib/librte_power/rte_power_kvm_vm.c
+++ b/lib/librte_power/rte_power_kvm_vm.c
@@ -106,7 +106,8 @@ send_msg(unsigned lcore_id, uint32_t scale_direction)
 	ret = guest_channel_send_msg(&pkt[lcore_id], lcore_id);
 	if (ret == 0)
 		return 1;
-	RTE_LOG(DEBUG, POWER, "Error sending message: %s\n", strerror(ret));
+	RTE_LOG(DEBUG, POWER, "Error sending message: %s\n", ret > 0 ? strerror(ret)
+			: "channel not connected");
 	return -1;
 }
 
-- 
2.5.5