[Libguestfs] [PATCH libnbd 1/2] nbd_connect_tcp: Try to return errno from underlying connect(2) call.

When we make a TCP connection we have to make multiple underlying connect(2) calls, once for each address returned by getaddrinfo. Unfortunately this meant that we lost the errno from any of these calls: $ nbdsh -c 'h.connect_tcp ("localhost", "nbd")' nbd.Error: nbd_connect_tcp: connect: localhost:nbd: could not connect to remote host This commit saves the errno from the first failed connect(2): $ ./run nbdsh -c 'h.connect_tcp ("localhost", "nbd")' nbd.Error: nbd_connect_tcp: connect: localhost:nbd: could not connect to remote host: Connection refused (ECONNREFUSED) --- generator/states-connect.c | 12 ++++++++++-- lib/internal.h | 1 + 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/generator/states-connect.c b/generator/states-connect.c index 9e2e1d4..e9b3582 100644 --- a/generator/states-connect.c +++ b/generator/states-connect.c @@ -128,6 +128,8 @@ disable_nagle (int sock) h->result = NULL; } + h->connect_errno = 0; + memset (&h->hints, 0, sizeof h->hints); h->hints.ai_family = AF_UNSPEC; h->hints.ai_socktype = SOCK_STREAM; @@ -160,7 +162,8 @@ disable_nagle (int sock) * Save errno from most recent connect(2) call. XXX */ SET_NEXT_STATE (%^START); - set_error (0, "connect: %s:%s: could not connect to remote host", + set_error (h->connect_errno, + "connect: %s:%s: could not connect to remote host", h->hostname, h->port); return -1; } @@ -182,6 +185,8 @@ disable_nagle (int sock) if (connect (fd, h->rp->ai_addr, h->rp->ai_addrlen) == -1) { if (errno != EINPROGRESS) { + if (h->connect_errno == 0) + h->connect_errno = errno; SET_NEXT_STATE (%NEXT_ADDRESS); return 0; } @@ -203,8 +208,11 @@ disable_nagle (int sock) /* This checks the status of the original connect call. */ if (status == 0) SET_NEXT_STATE (%^MAGIC.START); - else + else { + if (h->connect_errno == 0) + h->connect_errno = status; SET_NEXT_STATE (%NEXT_ADDRESS); + } return 0; CONNECT_TCP.NEXT_ADDRESS: diff --git a/lib/internal.h b/lib/internal.h index a48edff..ccaca32 100644 --- a/lib/internal.h +++ b/lib/internal.h @@ -188,6 +188,7 @@ struct nbd_handle { char *hostname, *port; struct addrinfo hints; struct addrinfo *result, *rp; + int connect_errno; /* When sending metadata contexts, this is used. */ size_t querynum; -- 2.23.0