Mercurial > dropbear
diff random.c @ 185:5ccad7634388
* warn if we seem to be blocking on /dev/random
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Sun, 24 Apr 2005 15:56:36 +0000 |
| parents | 4bd4fc8023bd |
| children | 06e326daf16a |
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--- a/random.c Sun Apr 24 10:30:33 2005 +0000 +++ b/random.c Sun Apr 24 15:56:36 2005 +0000 @@ -50,6 +50,7 @@ static void readrand(unsigned char* buf, unsigned int buflen) { + static int already_blocked = 0; int readfd; unsigned int readpos; int readlen; @@ -92,6 +93,24 @@ /* read the actual random data */ readpos = 0; do { + if (!already_blocked) + { + int ret; + struct timeval timeout; + fd_set read_fds; + + timeout.tv_sec = 2; /* two seconds should be enough */ + timeout.tv_usec = 0; + + FD_ZERO(&read_fds); + FD_SET(readfd, &read_fds); + ret = select(readfd + 1, &read_fds, NULL, NULL, &timeout); + if (ret == 0) + { + dropbear_log(LOG_INFO, "Warning: Reading the random source seems to have blocked.\nIf you experience problems, you probably need to find a better entropy source."); + already_blocked = 1; + } + } readlen = read(readfd, &buf[readpos], buflen - readpos); if (readlen <= 0) { if (readlen < 0 && errno == EINTR) {