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

0001 /*
0002  * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>
0003  *
0004  * Permission to use, copy, modify, and distribute this software for any
0005  * purpose with or without fee is hereby granted, provided that the above
0006  * copyright notice and this permission notice appear in all copies.
0007  *
0008  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
0009  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
0010  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
0011  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
0012  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
0013  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
0014  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
0015  */
0016 /* Test readlink /proc/self/map_files/... with minimum address. */
0017 #include <errno.h>
0018 #include <sys/types.h>
0019 #include <sys/stat.h>
0020 #include <fcntl.h>
0021 #include <stdio.h>
0022 #include <unistd.h>
0023 #include <sys/mman.h>
0024 #include <stdlib.h>
0025
0026 static void pass(const char *fmt, unsigned long a, unsigned long b)
0027 {
0028     char name[64];
0029     char buf[64];
0030
0031     snprintf(name, sizeof(name), fmt, a, b);
0032     if (readlink(name, buf, sizeof(buf)) == -1)
0033         exit(1);
0034 }
0035
0036 static void fail(const char *fmt, unsigned long a, unsigned long b)
0037 {
0038     char name[64];
0039     char buf[64];
0040
0041     snprintf(name, sizeof(name), fmt, a, b);
0042     if (readlink(name, buf, sizeof(buf)) == -1 && errno == ENOENT)
0043         return;
0044     exit(1);
0045 }
0046
0047 int main(void)
0048 {
0049     const int PAGE_SIZE = sysconf(_SC_PAGESIZE);
0050     /*
0051      * va_max must be enough bigger than vm.mmap_min_addr, which is
0052      * 64KB/32KB by default. (depends on CONFIG_LSM_MMAP_MIN_ADDR)
0053      */
0054     const unsigned long va_max = 1UL << 20;
0055     unsigned long va;
0056     void *p;
0057     int fd;
0058     unsigned long a, b;
0059
0060     fd = open("/dev/zero", O_RDONLY);
0061     if (fd == -1)
0062         return 1;
0063
0064     for (va = 0; va < va_max; va += PAGE_SIZE) {
0065         p = mmap((void *)va, PAGE_SIZE, PROT_NONE, MAP_PRIVATE|MAP_FILE|MAP_FIXED, fd, 0);
0066         if (p == (void *)va)
0067             break;
0068     }
0069     if (va == va_max) {
0070         fprintf(stderr, "error: mmap doesn't like you\n");
0071         return 1;
0072     }
0073
0074     a = (unsigned long)p;
0075     b = (unsigned long)p + PAGE_SIZE;
0076
0077     pass("/proc/self/map_files/%lx-%lx", a, b);
0078     fail("/proc/self/map_files/ %lx-%lx", a, b);
0079     fail("/proc/self/map_files/%lx -%lx", a, b);
0080     fail("/proc/self/map_files/%lx- %lx", a, b);
0081     fail("/proc/self/map_files/%lx-%lx ", a, b);
0082     fail("/proc/self/map_files/0%lx-%lx", a, b);
0083     fail("/proc/self/map_files/%lx-0%lx", a, b);
0084     if (sizeof(long) == 4) {
0085         fail("/proc/self/map_files/100000000%lx-%lx", a, b);
0086         fail("/proc/self/map_files/%lx-100000000%lx", a, b);
0087     } else if (sizeof(long) == 8) {
0088         fail("/proc/self/map_files/10000000000000000%lx-%lx", a, b);
0089         fail("/proc/self/map_files/%lx-10000000000000000%lx", a, b);
0090     } else
0091         return 1;
0092
0093     return 0;
0094 }