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avoid variable length arrays #15577

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avoid variable length arrays #15577

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ae11ee5
net/usrsock/usrsock_sendmsg.c: avoid using variable length array
yamt Jan 16, 2025
9c8b68c
sim: add -Wvla
yamt Jan 16, 2025
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16 changes: 14 additions & 2 deletions net/usrsock/usrsock_sendmsg.c
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Original file line number Diff line number Diff line change
Expand Up @@ -36,6 +36,7 @@
#include <arch/irq.h>

#include <sys/socket.h>
#include <nuttx/kmalloc.h>
#include <nuttx/net/net.h>
#include <nuttx/net/usrsock.h>

Expand Down Expand Up @@ -142,9 +143,18 @@ static int do_sendto_request(FAR struct usrsock_conn_s *conn,
{
};

struct iovec bufs[2 + msg->msg_iovlen];
struct iovec *bufs;
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FAR

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oops. thank you.

size_t iovlen;
int ret;
int i;

iovlen = 2 + msg->msg_iovlen;
bufs = kmm_malloc(sizeof(*bufs) * iovlen);
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could we use alloca or save the buffer to conn? it isn't good to do the allocation in the hot path.

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i guess we can have a special case for small iovlen.

if (bufs == NULL)
{
return -ENOMEM;
}

if (msg->msg_namelen > UINT16_MAX)
{
msg->msg_namelen = UINT16_MAX;
Expand Down Expand Up @@ -174,7 +184,9 @@ static int do_sendto_request(FAR struct usrsock_conn_s *conn,

memcpy(&bufs[2], msg->msg_iov, sizeof(struct iovec) * msg->msg_iovlen);

return usrsock_do_request(conn, bufs, nitems(bufs));
ret = usrsock_do_request(conn, bufs, iovlen);
kmm_free(bufs);
return ret;
}

/****************************************************************************
Expand Down