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OpenBSD lets you open /dev/random but not read it!

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rsc 2005-09-19 16:40:56 +00:00
parent 8e06ea1b42
commit 3a6c348fba
1 changed files with 6 additions and 4 deletions
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10
src/lib9/truerand.c
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@ -7,17 +7,19 @@ truerand(void)
int i, n; int i, n;
uchar buf[sizeof(ulong)]; uchar buf[sizeof(ulong)];
static int randfd = -1; static int randfd = -1;
static char *randfile;
if(randfd < 0){ if(randfd < 0){
randfd = open("/dev/random", OREAD); randfd = open(randfile="/dev/random", OREAD);
if(randfd < 0) /* OpenBSD lets you open /dev/random but not read it! */
randfd = open("/dev/srandom", OREAD); /* OpenBSD */ if(randfd < 0 || read(randfd, buf, 1) != 1)
randfd = open(randfile="/dev/srandom", OREAD); /* OpenBSD */
if(randfd < 0) if(randfd < 0)
sysfatal("can't open /dev/random: %r"); sysfatal("can't open /dev/random: %r");
fcntl(randfd, F_SETFD, FD_CLOEXEC); fcntl(randfd, F_SETFD, FD_CLOEXEC);
} }
for(i=0; i<sizeof(buf); i += n) for(i=0; i<sizeof(buf); i += n)
if((n = readn(randfd, buf+i, sizeof(buf)-i)) < 0) if((n = readn(randfd, buf+i, sizeof(buf)-i)) < 0)
sysfatal("can't read /dev/random: %r"); sysfatal("can't read %s: %r", randfile);
return *((ulong*)buf); return *((ulong*)buf);
} }