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| author | Tom Lane <tgl@sss.pgh.pa.us> | 2021-11-28 21:32:36 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2021-11-28 21:33:07 -0500 |
| commit | 3804539e48e794781c6145c7f988f5d507418fa8 (patch) | |
| tree | 317904b43ca8c1d510b23cb8fdd7b05a75e971bc /src/bin/initdb/initdb.c | |
| parent | f44ceb46ec2d8da48f6e145bf462d5620c25e079 (diff) | |
| download | postgresql-3804539e48e794781c6145c7f988f5d507418fa8.tar.gz | |
Replace random(), pg_erand48(), etc with a better PRNG API and algorithm.
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating
a bunch of platform dependencies as well as fundamentally-obsolete PRNG
code. In addition, this API replacement will ease replacing the
algorithm again in future, should that become necessary.
xoroshiro128** is a few percent slower than the drand48 family,
but it can produce full-width 64-bit random values not only 48-bit,
and it should be much more trustworthy. It's likely to be noticeably
faster than the platform's random(), depending on which platform you
are thinking about; and we can have non-global state vectors easily,
unlike with random(). It is not cryptographically strong, but neither
are the functions it replaces.
Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself
Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
Diffstat (limited to 'src/bin/initdb/initdb.c')
| -rw-r--r-- | src/bin/initdb/initdb.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c index 3c61c789e4..403adb0ee7 100644 --- a/src/bin/initdb/initdb.c +++ b/src/bin/initdb/initdb.c @@ -66,6 +66,7 @@ #include "common/file_perm.h" #include "common/file_utils.h" #include "common/logging.h" +#include "common/pg_prng.h" #include "common/restricted_token.h" #include "common/string.h" #include "common/username.h" @@ -880,9 +881,10 @@ choose_dsm_implementation(void) { #ifdef HAVE_SHM_OPEN int ntries = 10; + pg_prng_state prng_state; - /* Initialize random(); this function is its only user in this program. */ - srandom((unsigned int) (getpid() ^ time(NULL))); + /* Initialize prng; this function is its only user in this program. */ + pg_prng_seed(&prng_state, (uint64) (getpid() ^ time(NULL))); while (ntries > 0) { @@ -890,7 +892,7 @@ choose_dsm_implementation(void) char name[64]; int fd; - handle = random(); + handle = pg_prng_uint32(&prng_state); snprintf(name, 64, "/PostgreSQL.%u", handle); if ((fd = shm_open(name, O_CREAT | O_RDWR | O_EXCL, 0600)) != -1) { |