sd-bus: fix error handling on readv()

let's make sure we collect the right error code from errno, otherwise
we'll see EPERM (i.e. error 1) for all errors readv() returns (since it
returns -1 on error), including EAGAIN.

This is definitely backport material.

A fix-up for 3691bcf3c5eebdcca5b4f1c51c745441c57a6cd1.

Fixes: #16699

diff --git a/src/libsystemd/sd-bus/bus-socket.c b/src/libsystemd/sd-bus/bus-socket.c
index fc7e8e844abda5ed0864b3632894137b220d5710..de36a1f278af70654956e9b9467b98c529984939 100644 (file)
--- a/src/libsystemd/sd-bus/bus-socket.c
+++ b/src/libsystemd/sd-bus/bus-socket.c
@@ -544,9 +544,11 @@ static int bus_socket_read_auth(sd_bus *b) {
 
         iov = IOVEC_MAKE((uint8_t *)b->rbuffer + b->rbuffer_size, n - b->rbuffer_size);
 
-        if (b->prefer_readv)
+        if (b->prefer_readv) {
                 k = readv(b->input_fd, &iov, 1);
-        else {
+                if (k < 0)
+                        k = -errno;
+        } else {
                 mh = (struct msghdr) {
                         .msg_iov = &iov,
                         .msg_iovlen = 1,
@@ -1187,9 +1189,11 @@ int bus_socket_read_message(sd_bus *bus) {
 
         iov = IOVEC_MAKE((uint8_t *)bus->rbuffer + bus->rbuffer_size, need - bus->rbuffer_size);
 
-        if (bus->prefer_readv)
+        if (bus->prefer_readv) {
                 k = readv(bus->input_fd, &iov, 1);
-        else {
+                if (k < 0)
+                        k = -errno;
+        } else {
                 mh = (struct msghdr) {
                         .msg_iov = &iov,
                         .msg_iovlen = 1,