database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-12 13:01:09 +03:00
Code Activity

Try to detect process ID changes due to fork() calls in os_unix.c and

Browse Source 
reset the PRNG when a process ID change is detected.

FossilOrigin-Name: e1eba1fb09d7db49d77928bd115b27b8002ae640
This commit is contained in:
drh
2014-01-01 15:18:36 +00:00
parent fe98081e18
commit b00d862139
3 changed files with 28 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/os_unix.c
View File

@@ -260,6 +260,12 @@ struct unixFile {
#endif
};
/* This variable holds the process id (pid) from when the xRandomness()
** method was called. If xOpen() is called from a different process id,
** indicating that a fork() has occurred, the PRNG will be reset.
*/
static int randomnessPid = 0;
/*
** Allowed values for the unixFile.ctrlFlags bitmask:
*/
@@ -5651,6 +5657,16 @@ static int unixOpen(
|| eType==SQLITE_OPEN_TRANSIENT_DB || eType==SQLITE_OPEN_WAL
);
/* Detect a pid change and reset the PRNG. There is a race condition
** here such that two or more threads all trying to open databases at
** the same instant might all reset the PRNG. But multiple resets
** are harmless.
*/
if( randomnessPid!=getpid() ){
randomnessPid = getpid();
sqlite3_randomness(0,0);
}
memset(p, 0, sizeof(unixFile));
if( eType==SQLITE_OPEN_MAIN_DB ){
@@ -6038,18 +6054,18 @@ static int unixRandomness(sqlite3_vfs *NotUsed, int nBuf, char *zBuf){
** tests repeatable.
*/
memset(zBuf, 0, nBuf);
randomnessPid = getpid();
#if !defined(SQLITE_TEST)
{
int pid, fd, got;
int fd, got;
fd = robust_open("/dev/urandom", O_RDONLY, 0);
if( fd<0 ){
time_t t;
time(&t);
memcpy(zBuf, &t, sizeof(t));
pid = getpid();
memcpy(&zBuf[sizeof(t)], &pid, sizeof(pid));
assert( sizeof(t)+sizeof(pid)<=(size_t)nBuf );
nBuf = sizeof(t) + sizeof(pid);
memcpy(&zBuf[sizeof(t)], &randomnessPid, sizeof(randomnessPid));
assert( sizeof(t)+sizeof(randomnessPid)<=(size_t)nBuf );
nBuf = sizeof(t) + sizeof(randomnessPid);
}else{
do{ got = osRead(fd, zBuf, nBuf); }while( got<0 && errno==EINTR );
robust_close(0, fd, __LINE__);