tools/testing/selftests/proc/proc-self-map-files-002.c

   1 /*
   2  * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15  */
  16 /* Test readlink /proc/self/map_files/... with minimum address. */
  17 #include <errno.h>
  18 #include <sys/types.h>
  19 #include <sys/stat.h>
  20 #include <fcntl.h>
  21 #include <stdio.h>
  22 #include <unistd.h>
  23 #include <sys/mman.h>
  24 #include <stdlib.h>
  25
  26 static void pass(const char *fmt, unsigned long a, unsigned long b)
  27 {
  28         char name[64];
  29         char buf[64];
  30
  31         snprintf(name, sizeof(name), fmt, a, b);
  32         if (readlink(name, buf, sizeof(buf)) == -1)
  33                 exit(1);
  34 }
  35
  36 static void fail(const char *fmt, unsigned long a, unsigned long b)
  37 {
  38         char name[64];
  39         char buf[64];
  40
  41         snprintf(name, sizeof(name), fmt, a, b);
  42         if (readlink(name, buf, sizeof(buf)) == -1 && errno == ENOENT)
  43                 return;
  44         exit(1);
  45 }
  46
  47 int main(void)
  48 {
  49         const int PAGE_SIZE = sysconf(_SC_PAGESIZE);
  50         /*
  51          * va_max must be enough bigger than vm.mmap_min_addr, which is
  52          * 64KB/32KB by default. (depends on CONFIG_LSM_MMAP_MIN_ADDR)
  53          */
  54         const unsigned long va_max = 1UL << 20;
  55         unsigned long va;
  56         void *p;
  57         int fd;
  58         unsigned long a, b;
  59
  60         fd = open("/dev/zero", O_RDONLY);
  61         if (fd == -1)
  62                 return 1;
  63
  64         for (va = 0; va < va_max; va += PAGE_SIZE) {
  65                 p = mmap((void *)va, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0);
  66                 if (p == (void *)va)
  67                         break;
  68         }
  69         if (va == va_max) {
  70                 fprintf(stderr, "error: mmap doesn't like you\n");
  71                 return 1;
  72         }
  73
  74         a = (unsigned long)p;
  75         b = (unsigned long)p + PAGE_SIZE;
  76
  77         pass("/proc/self/map_files/%lx-%lx", a, b);
  78         fail("/proc/self/map_files/ %lx-%lx", a, b);
  79         fail("/proc/self/map_files/%lx -%lx", a, b);
  80         fail("/proc/self/map_files/%lx- %lx", a, b);
  81         fail("/proc/self/map_files/%lx-%lx ", a, b);
  82         fail("/proc/self/map_files/0%lx-%lx", a, b);
  83         fail("/proc/self/map_files/%lx-0%lx", a, b);
  84         if (sizeof(long) == 4) {
  85                 fail("/proc/self/map_files/100000000%lx-%lx", a, b);
  86                 fail("/proc/self/map_files/%lx-100000000%lx", a, b);
  87         } else if (sizeof(long) == 8) {
  88                 fail("/proc/self/map_files/10000000000000000%lx-%lx", a, b);
  89                 fail("/proc/self/map_files/%lx-10000000000000000%lx", a, b);
  90         } else
  91                 return 1;
  92
  93         return 0;
  94 }