// SPDX-License-Identifier: GPL-2.0

/*
 * Test that MAP_FIXED_NOREPLACE works.
 *
 * Copyright 2018, Jann Horn <jannh@google.com>
 * Copyright 2018, Michael Ellerman, IBM Corporation.
 */

#include <sys/mman.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#ifndef MAP_FIXED_NOREPLACE
#define MAP_FIXED_NOREPLACE 0x100000
#endif

#define BASE_ADDRESS    (256ul * 1024 * 1024)


static void dump_maps(void)
{
        char cmd[32];

        snprintf(cmd, sizeof(cmd), "cat /proc/%d/maps", getpid());
        system(cmd);
}

int main(void)
{
        unsigned long flags, addr, size, page_size;
        char *p;

        page_size = sysconf(_SC_PAGE_SIZE);

        flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE;

        // Check we can map all the areas we need below
        errno = 0;
        addr = BASE_ADDRESS;
        size = 5 * page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);

        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p == MAP_FAILED) {
                dump_maps();
                printf("Error: couldn't map the space we need for the test\n");
                return 1;
        }

        errno = 0;
        if (munmap((void *)addr, 5 * page_size) != 0) {
                dump_maps();
                printf("Error: munmap failed!?\n");
                return 1;
        }
        printf("unmap() successful\n");

        errno = 0;
        addr = BASE_ADDRESS + page_size;
        size = 3 * page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p == MAP_FAILED) {
                dump_maps();
                printf("Error: first mmap() failed unexpectedly\n");
                return 1;
        }

        /*
         * Exact same mapping again:
         *   base |  free  | new
         *     +1 | mapped | new
         *     +2 | mapped | new
         *     +3 | mapped | new
         *     +4 |  free  | new
         */
        errno = 0;
        addr = BASE_ADDRESS;
        size = 5 * page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p != MAP_FAILED) {
                dump_maps();
                printf("Error:1: mmap() succeeded when it shouldn't have\n");
                return 1;
        }

        /*
         * Second mapping contained within first:
         *
         *   base |  free  |
         *     +1 | mapped |
         *     +2 | mapped | new
         *     +3 | mapped |
         *     +4 |  free  |
         */
        errno = 0;
        addr = BASE_ADDRESS + (2 * page_size);
        size = page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p != MAP_FAILED) {
                dump_maps();
                printf("Error:2: mmap() succeeded when it shouldn't have\n");
                return 1;
        }

        /*
         * Overlap end of existing mapping:
         *   base |  free  |
         *     +1 | mapped |
         *     +2 | mapped |
         *     +3 | mapped | new
         *     +4 |  free  | new
         */
        errno = 0;
        addr = BASE_ADDRESS + (3 * page_size);
        size = 2 * page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p != MAP_FAILED) {
                dump_maps();
                printf("Error:3: mmap() succeeded when it shouldn't have\n");
                return 1;
        }

        /*
         * Overlap start of existing mapping:
         *   base |  free  | new
         *     +1 | mapped | new
         *     +2 | mapped |
         *     +3 | mapped |
         *     +4 |  free  |
         */
        errno = 0;
        addr = BASE_ADDRESS;
        size = 2 * page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p != MAP_FAILED) {
                dump_maps();
                printf("Error:4: mmap() succeeded when it shouldn't have\n");
                return 1;
        }

        /*
         * Adjacent to start of existing mapping:
         *   base |  free  | new
         *     +1 | mapped |
         *     +2 | mapped |
         *     +3 | mapped |
         *     +4 |  free  |
         */
        errno = 0;
        addr = BASE_ADDRESS;
        size = page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p == MAP_FAILED) {
                dump_maps();
                printf("Error:5: mmap() failed when it shouldn't have\n");
                return 1;
        }

        /*
         * Adjacent to end of existing mapping:
         *   base |  free  |
         *     +1 | mapped |
         *     +2 | mapped |
         *     +3 | mapped |
         *     +4 |  free  |  new
         */
        errno = 0;
        addr = BASE_ADDRESS + (4 * page_size);
        size = page_size;
        p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
        printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);

        if (p == MAP_FAILED) {
                dump_maps();
                printf("Error:6: mmap() failed when it shouldn't have\n");
                return 1;
        }

        addr = BASE_ADDRESS;
        size = 5 * page_size;
        if (munmap((void *)addr, size) != 0) {
                dump_maps();
                printf("Error: munmap failed!?\n");
                return 1;
        }
        printf("unmap() successful\n");

        printf("OK\n");
        return 0;
}