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#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include "doas.h"
#define PERSIST_DIR "/run/doas"
#define PERSIST_TIMEOUT 5 * 60
static int
ttyid(dev_t *tty)
{
int fd, i;
char buf[BUFSIZ], *p;
ssize_t n;
fd = open("/proc/self/stat", O_RDONLY);
if (fd == -1)
return -1;
n = read(fd, buf, sizeof(buf) - 1);
if (n >= 0)
buf[n] = '\0';
/* check that we read the whole file */
n = read(fd, buf, 1);
close(fd);
if (n != 0)
return -1;
p = strrchr(buf, ')');
if (!p)
return -1;
++p;
/* ttr_nr is the 5th field after executable name, so skip the next 4 */
for (i = 0; i < 4; ++i) {
p = strchr(++p, ' ');
if (!p)
return -1;
}
*tty = strtol(p, &p, 10);
if (*p != ' ')
return -1;
return 0;
}
static int
persistpath(char *buf, size_t len)
{
dev_t tty;
int n;
if (ttyid(&tty) < 0)
return -1;
n = snprintf(buf, len, PERSIST_DIR "/%ju-%ju", (uintmax_t)getuid(), (uintmax_t)tty);
if (n < 0 || n >= (int)len)
return -1;
return 0;
}
int
openpersist(int *valid)
{
char path[256];
struct stat st;
struct timespec ts;
int fd;
if (stat(PERSIST_DIR, &st) < 0) {
if (errno != ENOENT)
return -1;
if (mkdir(PERSIST_DIR, 0700) < 0)
return -1;
} else if (st.st_uid != 0 || st.st_mode != (S_IFDIR | 0700)) {
return -1;
}
if (persistpath(path, sizeof(path)) < 0)
return -1;
fd = open(path, O_RDONLY);
if (fd == -1) {
char tmp[256];
struct timespec ts[2] = { { .tv_nsec = UTIME_OMIT }, { 0 } };
int n;
n = snprintf(tmp, sizeof(tmp), PERSIST_DIR "/.tmp-%d", getpid());
if (n < 0 || n >= (int)sizeof(tmp))
return -1;
fd = open(tmp, O_RDONLY | O_CREAT | O_EXCL, 0);
if (fd == -1)
return -1;
if (futimens(fd, ts) < 0 || rename(tmp, path) < 0) {
close(fd);
unlink(tmp);
return -1;
}
*valid = 0;
} else {
*valid = clock_gettime(CLOCK_BOOTTIME, &ts) == 0 &&
fstat(fd, &st) == 0 &&
(ts.tv_sec < st.st_mtim.tv_sec ||
(ts.tv_sec == st.st_mtim.tv_sec && ts.tv_nsec < st.st_mtim.tv_nsec)) &&
st.st_mtime - ts.tv_sec <= PERSIST_TIMEOUT;
}
return fd;
}
int
setpersist(int fd)
{
struct timespec times[2];
if (clock_gettime(CLOCK_BOOTTIME, ×[1]) < 0)
return -1;
times[0].tv_nsec = UTIME_OMIT;
times[1].tv_sec += PERSIST_TIMEOUT;
return futimens(fd, times);
}
int
clearpersist(void)
{
char path[256];
if (persistpath(path, sizeof(path)) < 0)
return -1;
if (unlink(path) < 0 && errno != ENOENT)
return -1;
return 0;
}
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