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Adapt to modern linux utmp structure: microsecond timestamps, IPv6

This commit is contained in:
hjp 2016-07-05 19:13:09 +00:00
parent dd02446c69
commit 0984229b9b
1 changed files with 33 additions and 3 deletions
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36
prwtmp/prwtmp.c
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@ -1,9 +1,12 @@
char prwtmp_c_rcs_id[] =
"$Id: prwtmp.c,v 1.2 1998-05-28 16:18:21 hjp Exp $";
"$Id: prwtmp.c,v 1.3 2016-07-05 19:13:09 hjp Exp $";
/*
* prwtmp - print wtmp to stdout
*
* $Log: prwtmp.c,v $
* Revision 1.3 2016-07-05 19:13:09 hjp
* Adapt to modern linux utmp structure: microsecond timestamps, IPv6
*
* Revision 1.2 1998-05-28 16:18:21 hjp
* use GNUmakerules/GNUmakevars for CC and INSTALL.
* Bug fix: initial offset wasn't initialized
@ -16,10 +19,12 @@ char prwtmp_c_rcs_id[] =
*/
#include <assert.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <time.h>
#include <sys/types.h>
#include <unistd.h>
@ -33,6 +38,28 @@ void usage(void) {
}
/* The address is declared as a int32_t[], but it's really just an array
* of bytes
*/
void print_addr(void *p, size_t sz) {
uint8_t *pp = p;
if (sz == 4) {
/* assume ipv4 */
char buf[16];
snprintf(buf, sizeof(buf), "%d.%d.%d.%d", pp[0], pp[1], pp[2], pp[3]);
printf("%-*s ", sizeof(buf), buf);
} else {
/* assume ipv6 */
for (int i = 0; i < sz; i += 2) {
if (i > 0) printf(":");
printf("%02x%02x", pp[i], pp[i+1]);
}
printf(" ");
}
}
int main (int argc, char **argv) {
FILE *fp;
struct utmp u;
@ -81,7 +108,7 @@ int main (int argc, char **argv) {
strftime(tbuf, (int)sizeof(tbuf), "%Y-%m-%d %H:%M:%S",
localtime(&u.ut_time));
printf("%s ", tbuf);
printf("%s.%06d ", tbuf, (int)u.ut_tv.tv_usec);
printf("%-*.*s ",
(int)sizeof(u.ut_user),
(int)sizeof(u.ut_user),
@ -102,9 +129,12 @@ int main (int argc, char **argv) {
(int)sizeof(u.ut_host),
(int)sizeof(u.ut_host),
u.ut_host);
printf("%08lx", (unsigned long)u.ut_addr);
// printf("%08lx ", (unsigned long)u.ut_addr);
print_addr(u.ut_addr_v6, sizeof(u.ut_addr_v6));
printf("%10ld ", (long)u.ut_session); // either long or int32_t, so 10 digits should be enough
printf("\n");
}
return 0;
}
// vim: tw=132 sw=8