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| author | H. Peter Anvin <hpa@zytor.com> | 2008-01-16 13:53:56 -0500 |
|---|---|---|
| committer | Karel Zak <kzak@redhat.com> | 2008-01-28 14:55:04 +0100 |
| commit | f26873dc4ded29660c89e53e303d39555d3569b5 (patch) | |
| tree | 23b47786acefda9a2b360b7b5d35ce0401169e39 /fdisk | |
| parent | 30568eec590764ab5cdd263a054df2c9fa38286f (diff) | |
| download | util-linux-old-f26873dc4ded29660c89e53e303d39555d3569b5.tar.gz | |
fdisk: better fallback for get_random_id()
When /dev/urandom is not available, we have to use some kind of a hack
to generate a random MBR identifier. Use a better fallback that
incorporates the clock down to microsecond granularity.
Signed-off-by: H. Peter Anvin" <hpa@zytor.com>
Diffstat (limited to 'fdisk')
| -rw-r--r-- | fdisk/fdisk.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fdisk/fdisk.c b/fdisk/fdisk.c index cc71c5c4..ede41b3e 100644 --- a/fdisk/fdisk.c +++ b/fdisk/fdisk.c @@ -18,6 +18,7 @@ #include <errno.h> #include <getopt.h> #include <sys/stat.h> +#include <sys/time.h> #include <time.h> #include "nls.h" @@ -148,6 +149,7 @@ get_random_id(void) { int fd; unsigned int v; ssize_t rv = -1; + struct timeval tv; fd = open("/dev/urandom", O_RDONLY); if (fd >= 0) { @@ -159,7 +161,8 @@ get_random_id(void) { return v; /* Fallback: sucks, but better than nothing */ - return (unsigned int)(getpid() + time(NULL)); + gettimeofday(&tv, NULL); + return (unsigned int)(tv.tv_sec + (tv.tv_usec << 12) + getpid()); } /* normally O_RDWR, -l option gives O_RDONLY */ |