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authorLennart Poettering <lennart@poettering.net>2014-10-30 21:34:49 -0400
committerAnthony G. Basile <blueness@gentoo.org>2014-10-30 21:34:49 -0400
commitc306f4eab68ed5c084f993499a323cc98b480574 (patch)
tree05501c837d67d81a36fa157ee67f029b1f0e684d /src
parent25268b958a8d5cd703b2cd442004cbbee96043e0 (diff)
util: unify how we see srand()
Signed-off-by: Anthony G. Basile <blueness@gentoo.org>
Diffstat (limited to 'src')
-rw-r--r--src/cdrom_id/cdrom_id.c2
-rw-r--r--src/scsi_id/scsi_serial.c2
-rw-r--r--src/shared/util.c53
-rw-r--r--src/shared/util.h1
4 files changed, 33 insertions, 25 deletions
diff --git a/src/cdrom_id/cdrom_id.c b/src/cdrom_id/cdrom_id.c
index 9b3ab7021e..e13657b495 100644
--- a/src/cdrom_id/cdrom_id.c
+++ b/src/cdrom_id/cdrom_id.c
@@ -925,7 +925,7 @@ int main(int argc, char *argv[])
goto exit;
}
- srand((unsigned int)getpid());
+ initialize_srand();
for (cnt = 20; cnt > 0; cnt--) {
struct timespec duration;
diff --git a/src/scsi_id/scsi_serial.c b/src/scsi_id/scsi_serial.c
index 1806498503..3e30aed419 100644
--- a/src/scsi_id/scsi_serial.c
+++ b/src/scsi_id/scsi_serial.c
@@ -865,7 +865,7 @@ int scsi_get_serial(struct udev *udev,
int retval;
memzero(dev_scsi->serial, len);
- srand((unsigned int)getpid());
+ initialize_srand();
for (cnt = 20; cnt > 0; cnt--) {
struct timespec duration;
diff --git a/src/shared/util.c b/src/shared/util.c
index 3cad297873..e953363483 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -701,8 +701,36 @@ int dev_urandom(void *p, size_t n) {
return 0;
}
-void random_bytes(void *p, size_t n) {
+void initialize_srand(void) {
static bool srand_called = false;
+ unsigned x;
+#ifdef HAVE_SYS_AUXV_H
+ void *auxv;
+#endif
+
+ if (srand_called)
+ return;
+
+ x = 0;
+
+#ifdef HAVE_SYS_AUXV_H
+ /* The kernel provides us with a bit of entropy in auxv, so
+ * let's try to make use of that to seed the pseudo-random
+ * generator. It's better than nothing... */
+
+ auxv = (void*) getauxval(AT_RANDOM);
+ if (auxv)
+ x ^= *(unsigned*) auxv;
+#endif
+
+ x ^= (unsigned) now(CLOCK_REALTIME);
+ x ^= (unsigned) gettid();
+
+ srand(x);
+ srand_called = true;
+}
+
+void random_bytes(void *p, size_t n) {
uint8_t *q;
int r;
@@ -713,28 +741,7 @@ void random_bytes(void *p, size_t n) {
/* If some idiot made /dev/urandom unavailable to us, he'll
* get a PRNG instead. */
- if (!srand_called) {
- unsigned x = 0;
-
-#ifdef HAVE_SYS_AUXV_H
- /* The kernel provides us with a bit of entropy in
- * auxv, so let's try to make use of that to seed the
- * pseudo-random generator. It's better than
- * nothing... */
-
- void *auxv;
-
- auxv = (void*) getauxval(AT_RANDOM);
- if (auxv)
- x ^= *(unsigned*) auxv;
-#endif
-
- x ^= (unsigned) now(CLOCK_REALTIME);
- x ^= (unsigned) gettid();
-
- srand(x);
- srand_called = true;
- }
+ initialize_srand();
for (q = p; q < (uint8_t*) p + n; q ++)
*q = rand();
diff --git a/src/shared/util.h b/src/shared/util.h
index 9550aa19f9..f57a73cec6 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -192,6 +192,7 @@ bool ignore_file(const char *filename) _pure_;
int dev_urandom(void *p, size_t n);
void random_bytes(void *p, size_t n);
+void initialize_srand(void);
/* For basic lookup tables with strictly enumerated entries */
#define __DEFINE_STRING_TABLE_LOOKUP(name,type,scope) \