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#include "userlist.h"
#include "util.h"
#include <stdlib.h>
#include <utmp.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <time.h>
#include <ctype.h>
#include <signal.h>
#define TRUE 1
#define FALSE 0
#define MIN(a,b) ((a) < (b) ? (a) : (b))
static void getSessionData( struct user * user );
static void fixString( char *buffer, int maxLen )
{
while ( *buffer != '\0' && maxLen-- > 1 ) {
if ( *buffer == ' ' || *buffer == '\t' || *buffer == '\r' || *buffer == '\n' ) {
*buffer = '_';
}
buffer++;
}
*buffer = '\0';
}
static time_t lastActivity( char *line ) {
struct stat s;
char dev[40];
snprintf( dev, sizeof(dev), "/dev/%s", line );
if ( stat( dev, &s ) != 0 || s.st_atime == 0 )
return -1;
return s.st_atime;
}
int getUserList( struct user *outbuf, int size )
{
int fh = open( "/run/utmp", O_RDONLY );
if ( fh == -1 )
return 0;
// Mark
int deadzone = 0;
for ( int i = 0; i < size; ++i ) {
if ( outbuf[i].user[0] != '\0' ) {
deadzone = i + 1;
}
outbuf[i].mark = false;
}
struct utmp buffer[100];
ssize_t len = read( fh, buffer, sizeof(buffer) );
int num = len / sizeof(struct utmp);
for ( int i = 0; i < num; ++i ) {
struct utmp *u = buffer + i;
if ( u->ut_type != USER_PROCESS )
continue; // Not user session
if ( u->ut_user[0] == '\0' )
continue; // Empty username!?
// Check if alive
if ( kill( u->ut_pid, 0 ) != 0 )
continue;
// Make sure these contain anything
if ( u->ut_line[0] == '\0' ) {
snprintf( u->ut_line, UT_LINESIZE, "-" );
}
if ( u->ut_host[0] == '\0' ) {
snprintf( u->ut_host, UT_HOSTSIZE, "-" );
}
// No spaces, null terminated
fixString( u->ut_user, UT_NAMESIZE );
fixString( u->ut_line, UT_LINESIZE );
fixString( u->ut_host, UT_HOSTSIZE );
// Find slot in outbuf (matching one, first free one if not found)
int use = -1;
for ( int j = 0; j < deadzone; ++j ) {
if ( outbuf[j].user[0] == '\0' ) {
if ( use == -1 ) {
use = j;
}
} else if ( outbuf[j].sessionLeader == u->ut_pid
&& strcmp( outbuf[j].user, u->ut_user ) == 0
&& strcmp( outbuf[j].device, u->ut_line ) == 0 ) {
use = j;
break;
}
}
if ( use == -1 ) { // Not found and no free slot, expand if possible
if ( deadzone >= size ) // No more slots :-/
continue;
use = deadzone++;
}
if ( outbuf[use].user[0] == '\0' ) {
// New entry, init
memset( &outbuf[use], 0, sizeof(outbuf[use]) );
snprintf( outbuf[use].user, STRLEN, "%.*s",
(int)MIN( UT_NAMESIZE, STRLEN-1 ), u->ut_user );
snprintf( outbuf[use].device, STRLEN, "%.*s",
(int)MIN( UT_LINESIZE, STRLEN-1 ), u->ut_line );
if ( u->ut_host[0] == ':' && isdigit( u->ut_host[1] ) ) {
snprintf( outbuf[use].display, STRLEN, "%.*s",
(int)MIN( UT_HOSTSIZE, STRLEN-1 ), u->ut_host );
}
outbuf[use].sessionLeader = u->ut_pid;
getSessionData( &outbuf[use] );
printf( "New Session: '%s' on '%s', Display '%s', logind session '%s', login pid '%d', utmp pid '%d'.\n", outbuf[use].user, outbuf[use].device, outbuf[use].display, outbuf[use].sessionName, (int)outbuf[use].sessionHead, (int)outbuf[use].sessionLeader );
}
outbuf[use].mark = true;
// Reset offset if timestamp changed
// but ONLY if this isn't a known X session
if ( outbuf[use].display[0] == '\0' ) {
const time_t la = lastActivity( outbuf[use].device );
if ( outbuf[use].lastActivity != la ) {
outbuf[use].lastActivity = la;
outbuf[use].lastActivityOffset = 0;
}
}
}
close( fh );
// Compact
for ( int i = 0; i < deadzone; ++i ) {
if ( outbuf[i].mark )
continue; // In use
do {
deadzone--;
if ( outbuf[deadzone].mark ) {
outbuf[i] = outbuf[deadzone];
outbuf[deadzone].user[0] = '\0';
break;
}
} while ( deadzone > i );
}
return deadzone;
}
static void getSessionData( struct user * user )
{
char buffer[500];
snprintf( buffer, sizeof(buffer), "/proc/%d/cgroup", (int)user->sessionLeader );
FILE *fh = fopen( buffer, "r" );
if ( fh == NULL ) {
fprintf( stderr, "getSessionData: Cannot open %s to get logind session name\n", buffer );
return;
}
// Read from cgroup file
user->sessionName[0] = '\0';
char sessionName[40] = "";
while ( fgets( buffer, sizeof(buffer), fh ) != NULL ) {
const char *p = strstr( buffer, ":name=systemd:" );
if ( p == NULL )
continue;
p = strstr( p + 14, "/session-" );
if ( p == NULL )
continue;
copy( p + 9, sessionName, sizeof(sessionName), ".\n" );
break;
}
fclose( fh );
// Extract session leader pid from loginctl - it's often different from what utmp says
int fds[2];
if ( pipe( fds ) == -1 ) {
perror( "getSessionData: pipe for loginctl failed" );
return;
}
if ( doublefork() ) {
close( fds[0] );
redirect( -1, fds[1] );
run( false, "loginctl", "-p", "Name", "-p", "Class", "-p", "Leader", "show-session", sessionName, (char*)NULL );
}
close( fds[1] );
char lcName[100] = "", lcClass[100] = "", lcLeader[100] = "";
if ( ! waitRead( fds[0], 2000 ) ) {
fprintf( stderr, "getSessionData: loginctl timed out.\n" );
} else {
char output[4000] = "\n";
char *pos = output + 1, *end = output + sizeof(output) - 1;
do {
ssize_t ret = read( fds[0], pos, end - pos );
if ( ret == -1 ) {
if ( errno == EINTR )
continue;
perror( "getSessionData: read() from loginctl failed" );
break;
}
if ( ret == 0 )
break;
pos += ret;
} while ( waitRead( fds[0], 50 ) && pos < end );
*pos = '\0';
// Find strings
pos = strstr( output, "\nName=" );
if ( pos != NULL ) {
copy( pos + 6, lcName, sizeof(lcName), "\n \t" );
}
pos = strstr( output, "\nClass=" );
if ( pos != NULL ) {
copy( pos + 7, lcClass, sizeof(lcClass), "\n \t" );
}
pos = strstr( output, "\nLeader=" );
if ( pos != NULL ) {
copy( pos + 8, lcLeader, sizeof(lcLeader), "\n \t" );
}
}
close( fds[0] );
// Eval what we got - only honor output if it makes sense
if ( *lcName == '\0' ) {
fprintf( stderr, "getSessionData: Could not get user name for session %s\n", sessionName );
return;
}
if ( strcmp( lcName, user->user ) != 0 ) {
fprintf( stderr, "getSessionData: Sanity check failed. Session %s belongs to %s, but expected %s.\n", sessionName, lcName, user->user );
return;
}
if ( *lcClass != '\0' && strcmp( lcClass, "user" ) != 0 ) {
fprintf( stderr, "killSession: Sanity check failed. Session %s has Class=%s, but expected user.\n", sessionName, lcClass );
return;
}
// All good
snprintf( user->sessionName, sizeof(user->sessionName), "%s", sessionName );
user->sessionHead = atol( lcLeader );
if ( user->sessionHead < 10 ) {
fprintf( stderr, "getSessionData: Nonsensical Leader=%s reported by loginctl for session %s.\n", lcLeader, sessionName );
user->sessionHead = 0;
}
}
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