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#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <stdio.h>
#include <stdio_ext.h>
#include <dlfcn.h>
#include <sys/statvfs.h>
#include <sys/vfs.h>
#include <stdint.h>
#include <limits.h>
#include <sys/mount.h>
#include "dso.h"
#include "policy.h"
#include "selinux_internal.h"
#include "setrans_internal.h"
char *selinux_mnt = NULL;
int selinux_page_size = 0;
int obj_class_compat = 1;
int has_selinux_config = 0;
/* Verify the mount point for selinux file system has a selinuxfs.
If the file system:
* Exist,
* Is mounted with an selinux file system,
* The file system is read/write
* then set this as the default file system.
*/
static int verify_selinuxmnt(const char *mnt)
{
struct statfs sfbuf;
int rc;
do {
rc = statfs(mnt, &sfbuf);
} while (rc < 0 && errno == EINTR);
if (rc == 0) {
if ((uint32_t)sfbuf.f_type == (uint32_t)SELINUX_MAGIC) {
struct statvfs vfsbuf;
rc = statvfs(mnt, &vfsbuf);
if (rc == 0) {
if (!(vfsbuf.f_flag & ST_RDONLY)) {
set_selinuxmnt(mnt);
}
return 0;
}
}
}
return -1;
}
int selinuxfs_exists(void)
{
int exists = 0, mnt_rc = 0;
FILE *fp = NULL;
char *buf = NULL;
size_t len;
ssize_t num;
mnt_rc = mount("proc", "/proc", "proc", 0, 0);
fp = fopen("/proc/filesystems", "r");
if (!fp) {
exists = 1; /* Fail as if it exists */
goto out;
}
__fsetlocking(fp, FSETLOCKING_BYCALLER);
num = getline(&buf, &len, fp);
while (num != -1) {
if (strstr(buf, SELINUXFS)) {
exists = 1;
break;
}
num = getline(&buf, &len, fp);
}
free(buf);
fclose(fp);
out:
#ifndef MNT_DETACH
#define MNT_DETACH 2
#endif
if (mnt_rc == 0)
umount2("/proc", MNT_DETACH);
return exists;
}
hidden_def(selinuxfs_exists)
static void init_selinuxmnt(void)
{
char *buf=NULL, *p;
FILE *fp=NULL;
size_t len;
ssize_t num;
if (selinux_mnt)
return;
if (verify_selinuxmnt(SELINUXMNT) == 0) return;
if (verify_selinuxmnt(OLDSELINUXMNT) == 0) return;
/* Drop back to detecting it the long way. */
if (!selinuxfs_exists())
goto out;
/* At this point, the usual spot doesn't have an selinuxfs so
* we look around for it */
fp = fopen("/proc/mounts", "r");
if (!fp)
goto out;
__fsetlocking(fp, FSETLOCKING_BYCALLER);
while ((num = getline(&buf, &len, fp)) != -1) {
char *tmp;
p = strchr(buf, ' ');
if (!p)
goto out;
p++;
tmp = strchr(p, ' ');
if (!tmp)
goto out;
if (!strncmp(tmp + 1, SELINUXFS" ", strlen(SELINUXFS)+1)) {
*tmp = '\0';
break;
}
}
/* If we found something, dup it */
if (num > 0)
verify_selinuxmnt(p);
out:
free(buf);
if (fp)
fclose(fp);
return;
}
void fini_selinuxmnt(void)
{
free(selinux_mnt);
selinux_mnt = NULL;
}
hidden_def(fini_selinuxmnt)
void set_selinuxmnt(const char *mnt)
{
selinux_mnt = strdup(mnt);
}
hidden_def(set_selinuxmnt)
static void init_lib(void) __attribute__ ((constructor));
static void init_lib(void)
{
selinux_page_size = sysconf(_SC_PAGE_SIZE);
init_selinuxmnt();
#ifndef ANDROID
has_selinux_config = (access(SELINUXCONFIG, F_OK) == 0);
#endif
}
static void fini_lib(void) __attribute__ ((destructor));
static void fini_lib(void)
{
fini_selinuxmnt();
}
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