64 lines
1.6 KiB
Bash
Executable File
64 lines
1.6 KiB
Bash
Executable File
#!/bin/sh
|
|
set -e
|
|
|
|
# util-linux creates random UUIDs when uuid_generate_random is called
|
|
# Use LD_PRELOAD to replace uuid_generate_random with a less random version
|
|
|
|
# Don't run if gcc is not installed
|
|
if [ ! -e /usr/bin/cc ];
|
|
then
|
|
exit 0
|
|
fi
|
|
|
|
cat > unrandomize_uuid_generate_random.c << END_OF_SOURCE
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
|
|
#define SEQUENCE_FILENAME "/var/cache/unrandomize_uuid_generate_random.sequence_number"
|
|
|
|
/* https://tools.ietf.org/html/rfc4122 */
|
|
typedef unsigned char uuid_t[16];
|
|
|
|
/* Our pseudo-random version */
|
|
void uuid_generate_random(uuid_t out)
|
|
{
|
|
/* Nil UUID */
|
|
for (int i=0;i<16;i++) {
|
|
out[i] = 0x00;
|
|
}
|
|
out[6]=0x40; /* UUID version 4 means randomly generated */
|
|
out[8]=0x80; /* bit7=1,bit6=0 */
|
|
|
|
/* The file doesn't need to exist yet */
|
|
FILE *f = fopen(SEQUENCE_FILENAME, "rb");
|
|
if (f) {
|
|
fread(out+12, 4, 1, f);
|
|
fclose(f);
|
|
}
|
|
/* Use the next number. Endianness is not important */
|
|
(*(unsigned long*)(out+12))++;
|
|
|
|
unsigned long long epoch;
|
|
/* Use SOURCE_DATE_EPOCH when provided */
|
|
char *date = getenv("SOURCE_DATE_EPOCH");
|
|
if (date) {
|
|
epoch = strtoll(date, NULL, 10);
|
|
} else {
|
|
epoch = 0ll;
|
|
}
|
|
out[0] = (epoch & 0xFF000000) >> 24;
|
|
out[1] = (epoch & 0x00FF0000) >> 16;
|
|
out[2] = (epoch & 0x0000FF00) >> 8;
|
|
out[3] = (epoch & 0x000000FF);
|
|
|
|
/* Write the sequence number */
|
|
f = fopen(SEQUENCE_FILENAME, "wb");
|
|
if (f) {
|
|
fwrite(out+12, 4, 1, f);
|
|
fclose(f);
|
|
}
|
|
}
|
|
END_OF_SOURCE
|
|
/usr/bin/cc -shared -fPIC unrandomize_uuid_generate_random.c -Wall --pedantic -o /usr/lib/unrandomize_uuid_generate_random.so
|
|
rm -f unrandomize_uuid_generate_random.c
|