/* Copyright (C) 2016 Centro de Computacao Cientifica e Software Livre
* Departamento de Informatica - Universidade Federal do Parana - C3SL/UFPR
*
* This file is part of simmc-agent
*
* last.c Re-implementation of the 'last' command, this time
* for Linux. Yes I know there is BSD last, but I
* just felt like writing this. No thanks :-).
* Also, this version gives lots more info (especially with -x)
*
* Author: Miquel van Smoorenburg, miquels@cistron.nl
*
* Version: @(#)last 2.85 30-Jul-2004 miquels@cistron.nl
*
* This file is part of the sysvinit suite,
* Copyright (C) 1991-2004 Miquel van Smoorenburg.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "agent/linux/get_user_count.h"
#include <string>
#include <set>
/* Global variables */
struct utmplist *utmplist = NULL;
char *ufile; /* Filename of this file */
time_t lastdate; /* Last date we've seen */
struct tm * timeinfo;
set<string> users;
char yesterday[7], today[7];
/*
* Read one utmp entry, return in new format.
* Automatically reposition file pointer.
*/
static int uread(FILE *fp, struct utmp *u, int *quit) {
static int utsize, bpos;
static char buf[UCHUNKSIZE];
char tmp[1024];
static off_t fpos;
off_t o;
if (quit == NULL && u != NULL) {
/*
* Normal read.
*/
return fread(u, sizeof(struct utmp), 1, fp);
}
if (u == NULL) {
/*
* Initialize and position.
*/
utsize = sizeof(struct utmp);
fseeko(fp, 0, SEEK_END);
fpos = ftello(fp);
if (fpos == 0)
return 0;
o = ((fpos - 1) / UCHUNKSIZE) * UCHUNKSIZE;
if (fseeko(fp, o, SEEK_SET) < 0) {
fprintf(stderr, "ERROR: seek failed!\n");
return 0;
}
bpos = static_cast<int>(fpos - o);
if (fread(buf, bpos, 1, fp) != 1) {
fprintf(stderr, "ERROR: read failed!\n");
return 0;
}
fpos = o;
return 1;
}
/*
* Read one struct. From the buffer if possible.
*/
bpos -= utsize;
if (bpos >= 0) {
memcpy(u, buf + bpos, sizeof(struct utmp));
return 1;
}
/*
* Oops we went "below" the buffer. We should be able to
* seek back UCHUNKSIZE bytes.
*/
fpos -= UCHUNKSIZE;
if (fpos < 0)
return 0;
/*
* Copy whatever is left in the buffer.
*/
memcpy(tmp + (-bpos), buf, utsize + bpos);
if (fseeko(fp, fpos, SEEK_SET) < 0) {
perror("fseek");
return 0;
}
/*
* Read another UCHUNKSIZE bytes.
*/
if (fread(buf, UCHUNKSIZE, 1, fp) != 1) {
perror("fread");
return 0;
}
/*
* The end of the UCHUNKSIZE byte buffer should be the first
* few bytes of the current struct utmp.
*/
memcpy(tmp, buf + UCHUNKSIZE + bpos, -bpos);
bpos += UCHUNKSIZE;
memcpy(u, tmp, sizeof(struct utmp));
return 1;
}
static void list(struct utmp *p, time_t t, int what) {
time_t tmp;
struct user_log * u = (struct user_log *)malloc(sizeof(struct user_log));
char login[25], logout[25], month[3];
tmp = (time_t)p->ut_time;
timeinfo = gmtime(&tmp); // NOLINT(runtime/threadsafe_fn)
strftime(month, 3, "%m", timeinfo);
month[3]='\0';
snprintf(u->user, sizeof(u->user), p->ut_name, 0);
snprintf(login, sizeof(login), ctime(&tmp), 0);
u->login[0] = login[22];
u->login[1] = login[23];
u->login[2] = month[0];
u->login[3] = month[1];
u->login[4] = login[8] == ' '?'0':login[8];
u->login[5] = login[9];
u->login[6] = '\0';
switch (what) {
case R_NOW:
snprintf(u->logout, sizeof(u->logout), "999999");
break;
case R_PHANTOM:
snprintf(u->logout, sizeof(u->logout), "000000");
break;
case R_NORMAL:
timeinfo = gmtime(&t); // NOLINT(runtime/threadsafe_fn)
strftime(month, 3, "%m", timeinfo);
month[3]='\0';
snprintf(logout, sizeof(logout), ctime(&t), 0);
u->logout[0] = logout[22];
u->logout[1] = logout[23];
u->logout[2] = month[0];
u->logout[3] = month[1];
u->logout[4] = logout[8] == ' '?'0':logout[8];
u->logout[5] = logout[9];
u->logout[6] = '\0';
break;
}
if (!strcmp(u->logout, yesterday)) {
users.insert(u->user);
} else if (!strcmp(u->login, yesterday)) {
users.insert(u->user);
} else if (( strcmp(u->login, yesterday) &&
strcmp(u->login, today)) && (!strcmp(u->logout, today) ||
!strcmp(u->logout, "999999"))) {
users.insert(u->user);
}
}
static struct user_log * last_modified() {
FILE *fp; /* Filepointer of wtmp file */
struct utmp ut; /* Current utmp entry */
struct utmp oldut; /* Old utmp entry to check for duplicates */
struct utmplist *p, *next; /* Pointer into utmplist */
time_t lastboot = 0; /* Last boottime */
time_t lastdown; /* Last downtime */
time_t begintime; /* When wtmp begins */
int c, x; /* Scratch */
int skip = 1;
struct stat st; /* To stat the [uw]tmp file */
int quit = 0; /* Flag */
struct user_log * u = NULL;
struct user_log * v = NULL;
struct user_log * w = NULL;
/*
* Which file do we want to read?
*/
ufile = (char *)(WTMP_FILE);
time(&lastdown);
/*
* Fill in 'lastdate'
*/
lastdate = lastdown;
/*
* Open the utmp file
*/
if ((fp = fopen(ufile, "r")) == NULL) {
x = errno;
if (x == ENOENT)
// file not found
throw std::string(ufile) + std::string(": ") +
std::string(strerror(errno));
throw strerror(errno);
}
/*
* Optimize the buffer size.
*/
setvbuf(fp, NULL, _IOFBF, UCHUNKSIZE);
/*
* Read first structure to capture the time field
*/
if (uread(fp, &ut, NULL) == 1) {
begintime = ut.ut_time;
} else {
fstat(fileno(fp), &st);
begintime = st.st_ctime;
quit = 1;
}
/*
* Go to end of file minus one structure
* and/or initialize utmp reading code.
*/
uread(fp, NULL, NULL);
/*
* Read struct after struct backwards from the file.
*/
while (!quit && skip) {
if (uread(fp, &ut, &quit) != 1)
break;
if (memcmp(&ut, &oldut, sizeof(struct utmp)) == 0) continue;
memcpy(&oldut, &ut, sizeof(struct utmp));
lastdate = ut.ut_time;
/*
* Set ut_type to the correct type.
*/
if (strncmp(ut.ut_line, "~", 1) == 0) {
if (strncmp(ut.ut_user, "shutdown", 8) == 0)
ut.ut_type = SHUTDOWN_TIME;
else if (strncmp(ut.ut_user, "reboot", 6) == 0)
ut.ut_type = BOOT_TIME;
else if (strncmp(ut.ut_user, "runlevel", 8) == 0)
ut.ut_type = RUN_LVL;
/*def COMPAT*/
/*
* For stupid old applications that don't fill in
* ut_type correctly.
*/
} else {
if (ut.ut_type != DEAD_PROCESS &&
ut.ut_name[0] && ut.ut_line[0] &&
strcmp(ut.ut_name, "LOGIN") != 0)
ut.ut_type = USER_PROCESS;
/*
* Even worse, applications that write ghost
* entries: ut_type set to USER_PROCESS but
* empty ut_name...
*/
if (ut.ut_name[0] == 0)
ut.ut_type = DEAD_PROCESS;
/*
* Clock changes.
*/
if (strcmp(ut.ut_name, "date") == 0) {
if (ut.ut_line[0] == '|') ut.ut_type = OLD_TIME;
if (ut.ut_line[0] == '{') ut.ut_type = NEW_TIME;
}
}
switch (ut.ut_type) {
case USER_PROCESS:
/*
* This was a login - show the first matching
* logout record and delete all records with
* the same ut_line.
*/
c = 0;
skip = 0;
for (p = utmplist; p; p = next) {
next = p->next;
if (strncmp(p->ut.ut_line, ut.ut_line,
UT_LINESIZE) == 0) {
/* Show it */
if (c == 0) {
quit = 0;
list(&ut, p->ut.ut_time, R_NORMAL);
c = 1;
}
if (p->next) p->next->prev = p->prev;
if (p->prev)
p->prev->next = p->next;
else
utmplist = p->next;
free(p);
}
}
/*
* Not found? Then crashed, down, still
* logged in, or missing logout record.
*/
if (c == 0) {
c = R_NOW;
/* Is process still alive? */
if (ut.ut_pid > 0 &&
kill(ut.ut_pid, 0) != 0 &&
errno == ESRCH)
c = R_PHANTOM;
quit = 0;
list(&ut, lastboot, c);
}
/* FALLTHRU */
case DEAD_PROCESS:
/*
* Just store the data if it is
* interesting enough.
*/
if (ut.ut_line[0] == 0)
break;
p = (struct utmplist *)malloc(sizeof(struct utmplist));
if (p == NULL) {
throw std::string("ERROR: out of memory");
}
memcpy(&p->ut, &ut, sizeof(struct utmp));
p->next = utmplist;
p->prev = NULL;
if (utmplist) utmplist->prev = p;
utmplist = p;
break;
}
}
while (!quit) {
if (uread(fp, &ut, &quit) != 1)
break;
if (memcmp(&ut, &oldut, sizeof(struct utmp)) == 0) continue;
memcpy(&oldut, &ut, sizeof(struct utmp));
lastdate = ut.ut_time;
/*
* Set ut_type to the correct type.
*/
if (strncmp(ut.ut_line, "~", 1) == 0) {
if (strncmp(ut.ut_user, "shutdown", 8) == 0)
ut.ut_type = SHUTDOWN_TIME;
else if (strncmp(ut.ut_user, "reboot", 6) == 0)
ut.ut_type = BOOT_TIME;
else if (strncmp(ut.ut_user, "runlevel", 8) == 0)
ut.ut_type = RUN_LVL;
/*def COMPAT*/
/*
* For stupid old applications that don't fill in
* ut_type correctly.
*/
} else {
if (ut.ut_type != DEAD_PROCESS &&
ut.ut_name[0] && ut.ut_line[0] &&
strcmp(ut.ut_name, "LOGIN") != 0)
ut.ut_type = USER_PROCESS;
/*
* Even worse, applications that write ghost
* entries: ut_type set to USER_PROCESS but
* empty ut_name...
*/
if (ut.ut_name[0] == 0)
ut.ut_type = DEAD_PROCESS;
/*
* Clock changes.
*/
if (strcmp(ut.ut_name, "date") == 0) {
if (ut.ut_line[0] == '|') ut.ut_type = OLD_TIME;
if (ut.ut_line[0] == '{') ut.ut_type = NEW_TIME;
}
}
switch (ut.ut_type) {
case USER_PROCESS:
/*
* This was a login - show the first matching
* logout record and delete all records with
* the same ut_line.
*/
c = 0;
for (p = utmplist; p; p = next) {
next = p->next;
if (strncmp(p->ut.ut_line, ut.ut_line,
UT_LINESIZE) == 0) {
/* Show it */
if (c == 0) {
quit = 0;
list(&ut, p->ut.ut_time, R_NORMAL);
}
if (p->next) p->next->prev = p->prev;
if (p->prev)
p->prev->next = p->next;
else
utmplist = p->next;
free(p);
}
}
/*
* Not found? Then crashed, down, still
* logged in, or missing logout record.
*/
if (c == 0) {
c = R_NOW;
/* Is process still alive? */
if (ut.ut_pid > 0 &&
kill(ut.ut_pid, 0) != 0 &&
errno == ESRCH)
c = R_PHANTOM;
quit = 0;
list(&ut, lastboot, c);
}
/* FALLTHRU */
case DEAD_PROCESS:
/*
* Just store the data if it is
* interesting enough.
*/
if (ut.ut_line[0] == 0)
break;
p = (struct utmplist *)malloc(sizeof(struct utmplist));
if (p == NULL) {
throw std::string("ERROR: out of memory");
}
memcpy(&p->ut, &ut, sizeof(struct utmp));
p->next = utmplist;
p->prev = NULL;
if (utmplist) utmplist->prev = p;
utmplist = p;
break;
}
}
fclose(fp);
}
int get_user_count() {
/* The agent execution depends on the file '/var/log/wtmp', which is not
* present on some distros, such as OpenSUSE docker image. When this happens,
* this file is created and it's permissions setted.
*/
std::string wtmp_path = "/var/log/wtmp";
struct stat buffer;
if (stat(wtmp_path.c_str(), &buffer) != 0) { //file not exists
ofstream wtmp_file;
wtmp_file.open(wtmp_path.c_str());
wtmp_file.close();
chown(wtmp_path.c_str(), getpwnam("root")->pw_uid, getgrnam("tty")->gr_gid);
chmod(wtmp_path.c_str(), 664);
}
time_t rawtime;
time(&rawtime);
timeinfo = localtime(&rawtime); // NOLINT(runtime/threadsafe_fn)
strftime(today, 7, "%y%m%d", timeinfo);
today[6]='\0';
timeinfo->tm_mday--;
mktime(timeinfo);
strftime(yesterday, 7, "%y%m%d", timeinfo);
yesterday[6] = '\0';
last_modified();
return users.size();
}