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/* mcookie - generate a 128-bit random number (used for X "magic cookies")
*
* Copyright 2019 AD Isaac Dunham <ibid.ag@gmail.com>
*
* No standard.
* util-linux mcookie originally found the md5sum of several files in /proc
* and reported that; more recent versions use the best random number source
* and find the md5sum, thus wasting entropy.
* We just ask the system for 128 bits and print it.
*
*
USE_MCOOKIE(NEWTOY(mcookie, "v(verbose)V(version)", TOYFLAG_USR|TOYFLAG_BIN))
config MCOOKIE
bool "mcookie"
default n
help
usage: mcookie [-v | -V]
Generate a 128-bit random number from system sources.
-f and -m are not supported; md5 sums of arbitrary files are not a
good source of entropy
-h show help
-v show entropy source (verbose)
-V show version
*/
#define FOR_mcookie
#include "toys.h"
void mcookie_main(void)
{
int i;
if (toys.optflags & FLAG_V) {
puts("mcookie from toybox");
return;
}
xgetrandom(toybuf, 16, 0);
if (toys.optflags & FLAG_v) {
fputs("Got 16 bytes from xgetrandom()\n", stderr);
}
for (i = 0; i < 16; i++) {
sprintf(toybuf+16+2*i,"%02x", toybuf[i]);
}
toybuf[48] = '\0';
puts(toybuf + 16);
}
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