#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 "dso.h" #include "policy.h" #include "selinux_internal.h" #include "setrans_internal.h" char *selinux_mnt = NULL; int selinux_page_size = 0; 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; FILE *fp = NULL; char *buf = NULL; size_t len; ssize_t num; fp = fopen("/proc/filesystems", "r"); if (!fp) return 1; /* Fail as if it exists */ __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); 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(); }