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The driver no longer crashes the system when it couldn't allocate its

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resources.
It's now smarter and only initializes the random generator when the
device is opened, not in init_driver().
init_driver() assumed that this driver could not be opened under another
team as the kernel (which does not have to be true when it's rescanned).
Some more cleanup.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@5210 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2003-10-28 23:10:08 +00:00
parent 211e612940
commit b8fdbb4fff
1 changed files with 17 additions and 9 deletions
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26
src/add-ons/kernel/drivers/random/driver.c
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@ -85,7 +85,7 @@ typedef struct _ch_randgen {
static ch_randgen *sRandomEnv;
static unsigned int randcount=0;
static uint32 sRandomCount = 0;
static sem_id sRandomSem;
@ -310,7 +310,6 @@ new_chrand(const unsigned int inittimes)
static void
kill_chrand(ch_randgen *randgen)
{
memset(randgen, 0, sizeof (ch_randgen));
free(randgen);
}
@ -331,8 +330,9 @@ status_t
init_driver(void)
{
TRACE((DRIVER_NAME ": init_driver()\n"));
sRandomEnv = new_chrand(8);
sRandomSem = create_sem(1, "RNG semaphore");
set_sem_owner(sRandomSem, B_SYSTEM_TEAM);
return B_OK;
}
@ -376,7 +376,15 @@ static status_t
random_open(const char *name, uint32 flags, void **cookie)
{
TRACE((DRIVER_NAME ": open(\"%s\")\n", name));
return B_OK;
acquire_sem(sRandomSem);
sRandomEnv = new_chrand(8);
// the random generator is only initialized on demand, but
// remains valid as long as the driver is loaded
release_sem(sRandomSem);
return sRandomEnv != NULL ? B_OK : B_NO_MEMORY;
}
@ -388,18 +396,18 @@ random_read(void *cookie, off_t position, void *_buffer, size_t *_numBytes)
uint32 i, j;
acquire_sem(sRandomSem);
randcount += *_numBytes;
sRandomCount += *_numBytes;
/* Reseed if we have or are gonna use up > 1/16th the entropy around */
if (randcount >= NK/8) {
randcount = 0;
if (sRandomCount >= NK/8) {
sRandomCount = 0;
reseed(sRandomEnv, 1);
}
/* Yes, i know this is not the way we should do it. What we really should do is
/* ToDo: Yes, i know this is not the way we should do it. What we really should do is
* take the md5 or sha1 hash of the state of the pool, and return that. Someday.
*/
for (i = 0; i < (*_numBytes)/4; i++)
for (i = 0; i < (*_numBytes) / 4; i++)
buffer[i] = chrand32(sRandomEnv);
for (j = 0; j < (*_numBytes) % 4; j++)
buffer8[(i*4) + j] = chrand8(sRandomEnv);