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      1 #include <unistd.h>
      2 #include <fcntl.h>
      3 #include <string.h>
      4 #include <stdlib.h>
      5 #include <errno.h>
      6 #include <ctype.h>
      7 #include <stdio.h>
      8 #include <dlfcn.h>
      9 
     10 #ifdef DARWIN
     11 #include <sys/param.h>
     12 #include <sys/mount.h>
     13 #else
     14 #include <sys/vfs.h>
     15 #endif
     16 
     17 #include <stdint.h>
     18 #include <limits.h>
     19 
     20 #include "dso.h"
     21 #include "policy.h"
     22 #include "selinux_internal.h"
     23 
     24 char *selinux_mnt = NULL;
     25 int selinux_page_size = 0;
     26 
     27 static void init_selinuxmnt(void)
     28 {
     29 	char buf[BUFSIZ], *p;
     30 	FILE *fp=NULL;
     31 	struct statfs sfbuf;
     32 	int rc;
     33 	char *bufp;
     34 	int exists = 0;
     35 
     36 	if (selinux_mnt)
     37 		return;
     38 
     39 	/* We check to see if the preferred mount point for selinux file
     40 	 * system has a selinuxfs. */
     41 	do {
     42 		rc = statfs(SELINUXMNT, &sfbuf);
     43 	} while (rc < 0 && errno == EINTR);
     44 	if (rc == 0) {
     45 		if ((uint32_t)sfbuf.f_type == (uint32_t)SELINUX_MAGIC) {
     46 			selinux_mnt = strdup(SELINUXMNT);
     47 			return;
     48 		}
     49 	}
     50 
     51 	/* Drop back to detecting it the long way. */
     52 	fp = fopen("/proc/filesystems", "r");
     53 	if (!fp)
     54 		return;
     55 
     56 	while ((bufp = fgets(buf, sizeof buf - 1, fp)) != NULL) {
     57 		if (strstr(buf, "selinuxfs")) {
     58 			exists = 1;
     59 			break;
     60 		}
     61 	}
     62 
     63 	if (!exists)
     64 		goto out;
     65 
     66 	fclose(fp);
     67 
     68 	/* At this point, the usual spot doesn't have an selinuxfs so
     69 	 * we look around for it */
     70 	fp = fopen("/proc/mounts", "r");
     71 	if (!fp)
     72 		goto out;
     73 
     74 	while ((bufp = fgets(buf, sizeof buf - 1, fp)) != NULL) {
     75 		char *tmp;
     76 		p = strchr(buf, ' ');
     77 		if (!p)
     78 			goto out;
     79 		p++;
     80 		tmp = strchr(p, ' ');
     81 		if (!tmp)
     82 			goto out;
     83 		if (!strncmp(tmp + 1, "selinuxfs ", 10)) {
     84 			*tmp = '\0';
     85 			break;
     86 		}
     87 	}
     88 
     89 	/* If we found something, dup it */
     90 	if (bufp)
     91 		selinux_mnt = strdup(p);
     92 
     93       out:
     94 	if (fp)
     95 		fclose(fp);
     96 	return;
     97 }
     98 
     99 void fini_selinuxmnt(void)
    100 {
    101 	free(selinux_mnt);
    102 	selinux_mnt = NULL;
    103 }
    104 
    105 void set_selinuxmnt(char *mnt)
    106 {
    107 	selinux_mnt = strdup(mnt);
    108 }
    109 
    110 hidden_def(set_selinuxmnt)
    111 
    112 static void init_lib(void) __attribute__ ((constructor));
    113 static void init_lib(void)
    114 {
    115 	selinux_page_size = sysconf(_SC_PAGE_SIZE);
    116 	init_selinuxmnt();
    117 }
    118 
    119 static void fini_lib(void) __attribute__ ((destructor));
    120 static void fini_lib(void)
    121 {
    122 	fini_selinuxmnt();
    123 }
    124