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sockets.c: Destinct pointers for restrict parameters #602

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sockets.c: Destinct pointers for restrict parameters #602

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4 changes: 3 additions & 1 deletion src/libvncserver/sockets.c
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Original file line number Diff line number Diff line change
Expand Up @@ -669,6 +669,7 @@ rfbReadExactTimeout(rfbClientPtr cl, char* buf, int len, int timeout)
rfbSocket sock = cl->sock;
int n;
fd_set fds;
fd_set exceptfds;
struct timeval tv;

while (len > 0) {
Expand Down Expand Up @@ -715,9 +716,10 @@ rfbReadExactTimeout(rfbClientPtr cl, char* buf, int len, int timeout)
#endif
FD_ZERO(&fds);
FD_SET(sock, &fds);
exceptfds = fds;
tv.tv_sec = timeout / 1000;
tv.tv_usec = (timeout % 1000) * 1000;
n = select(sock+1, &fds, NULL, &fds, &tv);
n = select(sock+1, &fds, NULL, &exceptfds, &tv);
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…and if select() sets a bit in exceptfds where is it checked in the following code?

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Good point. I might have missed something there, but afaict nobody is checking fds currently.

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Okay. I am not familiar with the semantics of select() here, but wouldn't it be the same as passing NULL if the caller is not interested in the file descriptors anyway?

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According to the manpage, NULL is equivalent to an empty set. So this is different, as it specifies a set with one fd set.

Regarding the checking of the result of select(): I can not claim to fully understand the code, but only a single fd is set in fds (FD_SET(sock, &fds);). I guess this fd is probed afterwards, so that the result of select() is not needed.

if (n < 0) {
rfbLogPerror("ReadExact: select");
return n;
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