linux/tools/testing/selftests/proc/proc-self-map-files-002.c
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   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
  26static 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
  36static 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
  47int 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}
  95
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