// SPDX-License-Identifier: GPL-2.0-only
/*
 * Exercise /dev/mem mmap cases that have been troublesome in the past
 *
 * (c) Copyright 2007 Hewlett-Packard Development Company, L.P.
 *      Bjorn Helgaas <bjorn.helgaas@hp.com>
 */

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>
#include <linux/pci.h>

int sum;

static int map_mem(char *path, off_t offset, size_t length, int touch)
{
        int fd, rc;
        void *addr;
        int *c;

        fd = open(path, O_RDWR);
        if (fd == -1) {
                perror(path);
                return -1;
        }

        if (fnmatch("/proc/bus/pci/*", path, 0) == 0) {
                rc = ioctl(fd, PCIIOC_MMAP_IS_MEM);
                if (rc == -1)
                        perror("PCIIOC_MMAP_IS_MEM ioctl");
        }

        addr = mmap(NULL, length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, offset);
        if (addr == MAP_FAILED)
                return 1;

        if (touch) {
                c = (int *) addr;
                while (c < (int *) (addr + length))
                        sum += *c++;
        }

        rc = munmap(addr, length);
        if (rc == -1) {
                perror("munmap");
                return -1;
        }

        close(fd);
        return 0;
}

static int scan_tree(char *path, char *file, off_t offset, size_t length, int touch)
{
        struct dirent **namelist;
        char *name, *path2;
        int i, n, r, rc = 0, result = 0;
        struct stat buf;

        n = scandir(path, &namelist, 0, alphasort);
        if (n < 0) {
                perror("scandir");
                return -1;
        }

        for (i = 0; i < n; i++) {
                name = namelist[i]->d_name;

                if (fnmatch(".", name, 0) == 0)
                        goto skip;
                if (fnmatch("..", name, 0) == 0)
                        goto skip;

                path2 = malloc(strlen(path) + strlen(name) + 3);
                strcpy(path2, path);
                strcat(path2, "/");
                strcat(path2, name);

                if (fnmatch(file, name, 0) == 0) {
                        rc = map_mem(path2, offset, length, touch);
                        if (rc == 0)
                                fprintf(stderr, "PASS: %s 0x%lx-0x%lx is %s\n", path2, offset, offset + length, touch ? "readable" : "mappable");
                        else if (rc > 0)
                                fprintf(stderr, "PASS: %s 0x%lx-0x%lx not mappable\n", path2, offset, offset + length);
                        else {
                                fprintf(stderr, "FAIL: %s 0x%lx-0x%lx not accessible\n", path2, offset, offset + length);
                                return rc;
                        }
                } else {
                        r = lstat(path2, &buf);
                        if (r == 0 && S_ISDIR(buf.st_mode)) {
                                rc = scan_tree(path2, file, offset, length, touch);
                                if (rc < 0)
                                        return rc;
                        }
                }

                result |= rc;
                free(path2);

skip:
                free(namelist[i]);
        }
        free(namelist);
        return result;
}

char buf[1024];

static int read_rom(char *path)
{
        int fd, rc;
        size_t size = 0;

        fd = open(path, O_RDWR);
        if (fd == -1) {
                perror(path);
                return -1;
        }

        rc = write(fd, "1", 2);
        if (rc <= 0) {
                close(fd);
                perror("write");
                return -1;
        }

        do {
                rc = read(fd, buf, sizeof(buf));
                if (rc > 0)
                        size += rc;
        } while (rc > 0);

        close(fd);
        return size;
}

static int scan_rom(char *path, char *file)
{
        struct dirent **namelist;
        char *name, *path2;
        int i, n, r, rc = 0, result = 0;
        struct stat buf;

        n = scandir(path, &namelist, 0, alphasort);
        if (n < 0) {
                perror("scandir");
                return -1;
        }

        for (i = 0; i < n; i++) {
                name = namelist[i]->d_name;

                if (fnmatch(".", name, 0) == 0)
                        goto skip;
                if (fnmatch("..", name, 0) == 0)
                        goto skip;

                path2 = malloc(strlen(path) + strlen(name) + 3);
                strcpy(path2, path);
                strcat(path2, "/");
                strcat(path2, name);

                if (fnmatch(file, name, 0) == 0) {
                        rc = read_rom(path2);

                        /*
                         * It's OK if the ROM is unreadable.  Maybe there
                         * is no ROM, or some other error occurred.  The
                         * important thing is that no MCA happened.
                         */
                        if (rc > 0)
                                fprintf(stderr, "PASS: %s read %d bytes\n", path2, rc);
                        else {
                                fprintf(stderr, "PASS: %s not readable\n", path2);
                                return rc;
                        }
                } else {
                        r = lstat(path2, &buf);
                        if (r == 0 && S_ISDIR(buf.st_mode)) {
                                rc = scan_rom(path2, file);
                                if (rc < 0)
                                        return rc;
                        }
                }

                result |= rc;
                free(path2);

skip:
                free(namelist[i]);
        }
        free(namelist);
        return result;
}

int main(void)
{
        int rc;

        if (map_mem("/dev/mem", 0, 0xA0000, 1) == 0)
                fprintf(stderr, "PASS: /dev/mem 0x0-0xa0000 is readable\n");
        else
                fprintf(stderr, "FAIL: /dev/mem 0x0-0xa0000 not accessible\n");

        /*
         * It's not safe to blindly read the VGA frame buffer.  If you know
         * how to poke the card the right way, it should respond, but it's
         * not safe in general.  Many machines, e.g., Intel chipsets, cover
         * up a non-responding card by just returning -1, but others will
         * report the failure as a machine check.
         */
        if (map_mem("/dev/mem", 0xA0000, 0x20000, 0) == 0)
                fprintf(stderr, "PASS: /dev/mem 0xa0000-0xc0000 is mappable\n");
        else
                fprintf(stderr, "FAIL: /dev/mem 0xa0000-0xc0000 not accessible\n");

        if (map_mem("/dev/mem", 0xC0000, 0x40000, 1) == 0)
                fprintf(stderr, "PASS: /dev/mem 0xc0000-0x100000 is readable\n");
        else
                fprintf(stderr, "FAIL: /dev/mem 0xc0000-0x100000 not accessible\n");

        /*
         * Often you can map all the individual pieces above (0-0xA0000,
         * 0xA0000-0xC0000, and 0xC0000-0x100000), but can't map the whole
         * thing at once.  This is because the individual pieces use different
         * attributes, and there's no single attribute supported over the
         * whole region.
         */
        rc = map_mem("/dev/mem", 0, 1024*1024, 0);
        if (rc == 0)
                fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 is mappable\n");
        else if (rc > 0)
                fprintf(stderr, "PASS: /dev/mem 0x0-0x100000 not mappable\n");
        else
                fprintf(stderr, "FAIL: /dev/mem 0x0-0x100000 not accessible\n");

        scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 0xA0000, 1);
        scan_tree("/sys/class/pci_bus", "legacy_mem", 0xA0000, 0x20000, 0);
        scan_tree("/sys/class/pci_bus", "legacy_mem", 0xC0000, 0x40000, 1);
        scan_tree("/sys/class/pci_bus", "legacy_mem", 0, 1024*1024, 0);

        scan_rom("/sys/devices", "rom");

        scan_tree("/proc/bus/pci", "??.?", 0, 0xA0000, 1);
        scan_tree("/proc/bus/pci", "??.?", 0xA0000, 0x20000, 0);
        scan_tree("/proc/bus/pci", "??.?", 0xC0000, 0x40000, 1);
        scan_tree("/proc/bus/pci", "??.?", 0, 1024*1024, 0);

        return rc;
}