nl: improve how we surface errors

Closes #3057.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/nl.c b/src/lxc/nl.c
index 4de2bb82a6ebdd2caf009e517013ebd4ee0df932..dd94c09c886b1d5c81e728e28591ea8844971dee 100644 (file)
--- a/src/lxc/nl.c
+++ b/src/lxc/nl.c
@@ -19,16 +19,19 @@
 
 lxc_log_define(nl, lxc);
 
-extern size_t nlmsg_len(const struct nlmsg *nlmsg)
+size_t nlmsg_len(const struct nlmsg *nlmsg)
 {
        return nlmsg->nlmsghdr->nlmsg_len - NLMSG_HDRLEN;
 }
 
-extern void *nlmsg_data(struct nlmsg *nlmsg)
+void *nlmsg_data(struct nlmsg *nlmsg)
 {
-       char *data = ((char *)nlmsg) + NLMSG_HDRLEN;
+       char *data;
+
+       data = ((char *)nlmsg) + NLMSG_HDRLEN;
        if (!nlmsg_len(nlmsg))
-               return NULL;
+               return ret_set_errno(NULL, EINVAL);
+
        return data;
 }
 
@@ -40,7 +43,7 @@ static int nla_put(struct nlmsg *nlmsg, int attr,
        size_t tlen = NLMSG_ALIGN(nlmsg->nlmsghdr->nlmsg_len) + RTA_ALIGN(rtalen);
 
        if (tlen > nlmsg->cap)
-               return -ENOMEM;
+               return ret_errno(ENOMEM);
 
        rta = NLMSG_TAIL(nlmsg->nlmsghdr);
        rta->rta_type = attr;
@@ -48,41 +51,42 @@ static int nla_put(struct nlmsg *nlmsg, int attr,
        if (data && len)
                memcpy(RTA_DATA(rta), data, len);
        nlmsg->nlmsghdr->nlmsg_len = tlen;
+
        return 0;
 }
 
-extern int nla_put_buffer(struct nlmsg *nlmsg, int attr,
-                         const void *data, size_t size)
+int nla_put_buffer(struct nlmsg *nlmsg, int attr, const void *data, size_t size)
 {
        return nla_put(nlmsg, attr, data, size);
 }
 
-extern int nla_put_string(struct nlmsg *nlmsg, int attr, const char *string)
+int nla_put_string(struct nlmsg *nlmsg, int attr, const char *string)
 {
        return nla_put(nlmsg, attr, string, strlen(string) + 1);
 }
 
-extern int nla_put_u32(struct nlmsg *nlmsg, int attr, int value)
+int nla_put_u32(struct nlmsg *nlmsg, int attr, int value)
 {
        return nla_put(nlmsg, attr, &value, sizeof(value));
 }
 
-extern int nla_put_u16(struct nlmsg *nlmsg, int attr, unsigned short value)
+int nla_put_u16(struct nlmsg *nlmsg, int attr, unsigned short value)
 {
        return nla_put(nlmsg, attr, &value, 2);
 }
 
-extern int nla_put_attr(struct nlmsg *nlmsg, int attr)
+int nla_put_attr(struct nlmsg *nlmsg, int attr)
 {
        return nla_put(nlmsg, attr, NULL, 0);
 }
 
 struct rtattr *nla_begin_nested(struct nlmsg *nlmsg, int attr)
 {
-       struct rtattr *rtattr = NLMSG_TAIL(nlmsg->nlmsghdr);
+       struct rtattr *rtattr;
 
+       rtattr = NLMSG_TAIL(nlmsg->nlmsghdr);
        if (nla_put_attr(nlmsg, attr))
-               return NULL;
+               return ret_set_errno(NULL, ENOMEM);
 
        return rtattr;
 }
@@ -92,37 +96,34 @@ void nla_end_nested(struct nlmsg *nlmsg, struct rtattr *attr)
        attr->rta_len = (void *)NLMSG_TAIL(nlmsg->nlmsghdr) - (void *)attr;
 }
 
-extern struct nlmsg *nlmsg_alloc(size_t size)
+struct nlmsg *nlmsg_alloc(size_t size)
 {
-       struct nlmsg *nlmsg;
+       __do_free struct nlmsg *nlmsg = NULL;
        size_t len = NLMSG_HDRLEN + NLMSG_ALIGN(size);
 
-       nlmsg = (struct nlmsg *)malloc(sizeof(struct nlmsg));
+       nlmsg = malloc(sizeof(struct nlmsg));
        if (!nlmsg)
-               return NULL;
+               return ret_set_errno(NULL, ENOMEM);
 
-       nlmsg->nlmsghdr = (struct nlmsghdr *)malloc(len);
+       nlmsg->nlmsghdr = malloc(len);
        if (!nlmsg->nlmsghdr)
-               goto errout;
+               return ret_set_errno(NULL, ENOMEM);
 
        memset(nlmsg->nlmsghdr, 0, len);
        nlmsg->cap = len;
        nlmsg->nlmsghdr->nlmsg_len = NLMSG_HDRLEN;
 
-       return nlmsg;
-errout:
-       free(nlmsg);
-       return NULL;
+       return move_ptr(nlmsg);
 }
 
-extern void *nlmsg_reserve(struct nlmsg *nlmsg, size_t len)
+void *nlmsg_reserve(struct nlmsg *nlmsg, size_t len)
 {
        void *buf;
        size_t nlmsg_len = nlmsg->nlmsghdr->nlmsg_len;
        size_t tlen = NLMSG_ALIGN(len);
 
        if (nlmsg_len + tlen > nlmsg->cap)
-               return NULL;
+               return ret_set_errno(NULL, ENOMEM);
 
        buf = ((char *)(nlmsg->nlmsghdr)) + nlmsg_len;
        nlmsg->nlmsghdr->nlmsg_len += tlen;
@@ -133,29 +134,28 @@ extern void *nlmsg_reserve(struct nlmsg *nlmsg, size_t len)
        return buf;
 }
 
-extern struct nlmsg *nlmsg_alloc_reserve(size_t size)
+struct nlmsg *nlmsg_alloc_reserve(size_t size)
 {
        struct nlmsg *nlmsg;
 
        nlmsg = nlmsg_alloc(size);
        if (!nlmsg)
-               return NULL;
+               return ret_set_errno(NULL, ENOMEM);
 
        /* Just set message length to cap directly. */
        nlmsg->nlmsghdr->nlmsg_len = nlmsg->cap;
        return nlmsg;
 }
 
-extern void nlmsg_free(struct nlmsg *nlmsg)
+void nlmsg_free(struct nlmsg *nlmsg)
 {
-       if (!nlmsg)
-               return;
-
-       free(nlmsg->nlmsghdr);
-       free(nlmsg);
+       if (nlmsg) {
+               free(nlmsg->nlmsghdr);
+               free(nlmsg);
+       }
 }
 
-extern int __netlink_recv(struct nl_handler *handler, struct nlmsghdr *nlmsghdr)
+int __netlink_recv(struct nl_handler *handler, struct nlmsghdr *nlmsghdr)
 {
        int ret;
        struct sockaddr_nl nladdr;
@@ -182,26 +182,24 @@ again:
                if (errno == EINTR)
                        goto again;
 
-               return -1;
+               return ret_errno(errno);
        }
 
        if (!ret)
                return 0;
 
-       if (msg.msg_flags & MSG_TRUNC && (ret == nlmsghdr->nlmsg_len)) {
-               errno = EMSGSIZE;
-               ret = -1;
-       }
+       if (msg.msg_flags & MSG_TRUNC && (ret == nlmsghdr->nlmsg_len))
+               return ret_errno(EMSGSIZE);
 
        return ret;
 }
 
-extern int netlink_rcv(struct nl_handler *handler, struct nlmsg *answer)
+int netlink_rcv(struct nl_handler *handler, struct nlmsg *answer)
 {
        return __netlink_recv(handler, answer->nlmsghdr);
 }
 
-extern int __netlink_send(struct nl_handler *handler, struct nlmsghdr *nlmsghdr)
+int __netlink_send(struct nl_handler *handler, struct nlmsghdr *nlmsghdr)
 {
        int ret;
        struct sockaddr_nl nladdr;
@@ -223,7 +221,7 @@ extern int __netlink_send(struct nl_handler *handler, struct nlmsghdr *nlmsghdr)
 
        ret = sendmsg(handler->fd, &msg, MSG_NOSIGNAL);
        if (ret < 0)
-               return -1;
+               return ret_errno(errno);
 
        return ret;
 }
@@ -241,21 +239,19 @@ extern int __netlink_transaction(struct nl_handler *handler,
 
        ret = __netlink_send(handler, request);
        if (ret < 0)
-               return -1;
+               return ret;
 
        ret = __netlink_recv(handler, answer);
        if (ret < 0)
-               return -1;
+               return ret;
 
-       ret = 0;
        if (answer->nlmsg_type == NLMSG_ERROR) {
                struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(answer);
-               errno = -err->error;
                if (err->error < 0)
-                       ret = -1;
+                       return ret_errno(-err->error);
        }
 
-       return ret;
+       return 0;
 }
 
 extern int netlink_transaction(struct nl_handler *handler,
@@ -267,56 +263,44 @@ extern int netlink_transaction(struct nl_handler *handler,
 
 extern int netlink_open(struct nl_handler *handler, int protocol)
 {
+       __do_close int fd = -EBADF;
        socklen_t socklen;
        int sndbuf = 32768;
        int rcvbuf = 32768;
-       int err;
 
        memset(handler, 0, sizeof(*handler));
+       handler->fd = -EBADF;
 
-       handler->fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
-       if (handler->fd < 0)
-               return -errno;
+       fd = socket(AF_NETLINK, SOCK_RAW | SOCK_CLOEXEC, protocol);
+       if (fd < 0)
+               return ret_errno(errno);
 
-       if (setsockopt(handler->fd, SOL_SOCKET, SO_SNDBUF,
-                      &sndbuf, sizeof(sndbuf)) < 0)
-               goto err_with_errno;
+       if (setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &sndbuf, sizeof(sndbuf)) < 0)
+               return ret_errno(errno);
 
-       if (setsockopt(handler->fd, SOL_SOCKET, SO_RCVBUF,
-                      &rcvbuf,sizeof(rcvbuf)) < 0)
-               goto err_with_errno;
+       if (setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &rcvbuf,sizeof(rcvbuf)) < 0)
+               return ret_errno(errno);
 
        memset(&handler->local, 0, sizeof(handler->local));
        handler->local.nl_family = AF_NETLINK;
        handler->local.nl_groups = 0;
 
-       if (bind(handler->fd, (struct sockaddr*)&handler->local,
-                sizeof(handler->local)) < 0)
-               goto err_with_errno;
+       if (bind(fd, (struct sockaddr*)&handler->local, sizeof(handler->local)) < 0)
+               return ret_errno(errno);
 
        socklen = sizeof(handler->local);
-       if (getsockname(handler->fd, (struct sockaddr*)&handler->local,
-                       &socklen) < 0)
-               goto err_with_errno;
+       if (getsockname(fd, (struct sockaddr*)&handler->local, &socklen) < 0)
+               return ret_errno(errno);
 
-       if (socklen != sizeof(handler->local)) {
-               err = -EINVAL;
-               goto errclose;
-       }
+       if (socklen != sizeof(handler->local))
+               return ret_errno(EINVAL);
 
-       if (handler->local.nl_family != AF_NETLINK) {
-               err = -EINVAL;
-               goto errclose;
-       }
+       if (handler->local.nl_family != AF_NETLINK)
+               return ret_errno(EINVAL);
 
        handler->seq = time(NULL);
-
+       handler->fd = move_fd(fd);
        return 0;
-err_with_errno:
-       err = -errno;
-errclose:
-       close(handler->fd);
-       return err;
 }
 
 extern void netlink_close(struct nl_handler *handler)
@@ -330,9 +314,8 @@ int addattr(struct nlmsghdr *n, size_t maxlen, int type, const void *data,
        int len = RTA_LENGTH(alen);
        struct rtattr *rta;
 
-       errno = EMSGSIZE;
        if (NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen)
-               return -1;
+               return ret_errno(EMSGSIZE);
 
        rta = NLMSG_TAIL(n);
        rta->rta_type = type;