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#include <utmp.h>
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <unistd.h>
#include <bits/ensure.h>
#include <mlibc/debug.hpp>
/*
* The code in this file is largely based on glibc.
* This includes:
* - setutent
* - read_last_entry
* - getutent
* - getutent_r
* - endutent
*/
static int fd = -1;
static off_t offset;
static struct utmp last_entry;
void setutent(void) {
if(fd < 0) {
fd = open("/run/utmp", O_RDONLY | O_LARGEFILE | O_CLOEXEC);
if(fd == -1) {
return;
}
}
lseek(fd, 0, SEEK_SET);
offset = 0;
}
static ssize_t read_last_entry(void) {
struct utmp buf;
ssize_t bytes_read = pread(fd, &buf, sizeof(buf), offset);
if(bytes_read < 0) {
return -1;
} else if(bytes_read != sizeof(buf)) {
// EOF
return 0;
} else {
last_entry = buf;
offset += sizeof(buf);
return 1;
}
}
struct utmp *getutent(void) {
struct utmp *result;
static struct utmp *buf;
if(buf == NULL) {
buf = (struct utmp *)malloc(sizeof(struct utmp));
if(buf == NULL) {
return NULL;
}
}
if(getutent_r(buf, &result) < 0) {
return NULL;
}
return result;
}
int getutent_r(struct utmp *buf, struct utmp **res) {
int saved_errno = errno;
if(fd < 0) {
setutent();
}
ssize_t bytes_read = read_last_entry();
if(bytes_read <= 0) {
if(bytes_read == 0) {
errno = saved_errno;
*res = NULL;
return -1;
}
}
memcpy(buf, &last_entry, sizeof(struct utmp));
*res = buf;
return 0;
}
void endutent(void) {
if(fd >= 0) {
close(fd);
fd = -1;
}
}
struct utmp *pututline(const struct utmp *) {
mlibc::infoLogger() << "\e[31mmlibc: pututline() is a stub!\e[39m" << frg::endlog;
return NULL;
}
struct utmp *getutline(const struct utmp *) {
mlibc::infoLogger() << "\e[31mmlibc: getutline() is a stub!\e[39m" << frg::endlog;
return NULL;
}
int utmpname(const char *) {
mlibc::infoLogger() << "\e[31mmlibc: utmpname() is a stub!\e[39m" << frg::endlog;
return -1;
}
struct utmp *getutid(const struct utmp *) {
mlibc::infoLogger() << "\e[31mmlibc: getutid() is a stub!\e[39m" << frg::endlog;
return NULL;
}
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