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net: lwm2m: Fix poll fds handling

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Currently, functions for poll sock_fds array management are buggy, in
case there is another socket open (for instance the socket for firmware
update download), it could get overwritten, if the LwM2M socket was
closed and re-opened in a meantime (e. g. on registration timeout).

Fix this, by appending new entries to the sock_fds in continuous manner.
In case of removal, the deleted entry is overwritten by the last one,
and the last one is cleared.

Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
This commit is contained in:
Robert Lubos 2020-06-23 12:40:42 +02:00 • committed by Carles Cufí
commit d20b1aebf9
1 changed files with 22 additions and 20 deletions
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42
subsys/net/lib/lwm2m/lwm2m_engine.c
View file

@ -4171,36 +4171,38 @@ void lwm2m_engine_context_init(struct lwm2m_ctx *client_ctx)
int lwm2m_socket_add(struct lwm2m_ctx *ctx)
{
int i;
if (sock_nfds < MAX_POLL_FD) {
i = sock_nfds++;
} else {
for (i = 0; i < MAX_POLL_FD; i++) {
if (sock_ctx[i] == NULL) {
goto found;
}
}
if (sock_nfds >= MAX_POLL_FD) {
return -ENOMEM;
}
found:
sock_ctx[i] = ctx;
sock_fds[i].fd = ctx->sock_fd;
sock_fds[i].events = POLLIN;
sock_ctx[sock_nfds] = ctx;
sock_fds[sock_nfds].fd = ctx->sock_fd;
sock_fds[sock_nfds].events = POLLIN;
sock_nfds++;
return 0;
}
void lwm2m_socket_del(struct lwm2m_ctx *ctx)
{
for (int i = 0; i < sock_nfds; i++) {
if (sock_ctx[i] == ctx) {
sock_ctx[i] = NULL;
sock_fds[i].fd = -1;
sock_nfds--;
break;
if (sock_ctx[i] != ctx) {
continue;
}
sock_nfds--;
/* If not last, overwrite the entry with the last one. */
if (i < sock_nfds) {
sock_ctx[i] = sock_ctx[sock_nfds];
sock_fds[i].fd = sock_fds[sock_nfds].fd;
sock_fds[i].events = sock_fds[sock_nfds].events;
}
/* Remove the last entry. */
sock_ctx[sock_nfds] = NULL;
sock_fds[sock_nfds].fd = -1;
break;
}
}