Fix: recv creds comm should handle partial receive

Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/common/sessiond-comm/unix.c b/src/common/sessiond-comm/unix.c
index 0d7c95a7637638f066b28f0c2dbe14dc2bbd393d..2c87b82c451f87de02fb5db074cb24a32c752696 100644 (file)
--- a/src/common/sessiond-comm/unix.c
+++ b/src/common/sessiond-comm/unix.c
@@ -435,6 +435,7 @@ ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
        struct msghdr msg;
        struct iovec iov[1];
        ssize_t ret;
+       size_t len_last;
 #ifdef __linux__
        struct cmsghdr *cmptr;
        size_t sizeof_cred = sizeof(lttng_sock_cred);
@@ -461,12 +462,21 @@ ssize_t lttcomm_recv_creds_unix_sock(int sock, void *buf, size_t len,
 #endif /* __linux__ */
 
        do {
+               len_last = iov[0].iov_len;
                ret = recvmsg(sock, &msg, 0);
-       } while (ret < 0 && errno == EINTR);
+               if (ret > 0) {
+                       iov[0].iov_base += ret;
+                       iov[0].iov_len -= ret;
+                       assert(ret <= len_last);
+               }
+       } while ((ret > 0 && ret < len_last) || (ret < 0 && errno == EINTR));
        if (ret < 0) {
                PERROR("recvmsg fds");
                goto end;
+       } else if (ret > 0) {
+               ret = len;
        }
+       /* Else ret = 0 meaning an orderly shutdown. */
 
 #ifdef __linux__
        if (msg.msg_flags & MSG_CTRUNC) {