// https://syzkaller.appspot.com/bug?id=b798d2a1e35362e903d6c263ddc1743bf200b8f3
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <fcntl.h>
#include <dirent.h>
#include <string.h>
#include <errno.h>

#define MAX_ACPI_DEVS 256
char acpi_files[MAX_ACPI_DEVS][256];
int num_acpi_files = 0;

void *acpi_worker(void *arg) {
    char buf[256];
    for (int i = 0; i < 1000; i++) {
        for (int j = 0; j < num_acpi_files; j++) {
            int fd = open(acpi_files[j], O_RDONLY);
            if (fd < 0) {
                printf("[-] Failed to open %s: %s\n", acpi_files[j], strerror(errno));
                exit(1);
            }
            ssize_t n = read(fd, buf, sizeof(buf));
            if (n < 0) {
                printf("[-] Failed to read %s: %s\n", acpi_files[j], strerror(errno));
                exit(1);
            }
            if (close(fd) < 0) {
                printf("[-] Failed to close %s: %s\n", acpi_files[j], strerror(errno));
                exit(1);
            }
        }
    }
    return NULL;
}

int main() {
    setvbuf(stdout, NULL, _IONBF, 0);

    DIR *dir = opendir("/sys/bus/acpi/devices");
    if (!dir) {
        printf("[-] Failed to opendir /sys/bus/acpi/devices: %s\n", strerror(errno));
        exit(1);
    }
    printf("[+] opendir /sys/bus/acpi/devices successful.\n");

    struct dirent *ent;
    while ((ent = readdir(dir)) != NULL) {
        if (ent->d_name[0] == '.') continue;
        
        char path[256];
        snprintf(path, sizeof(path), "/sys/bus/acpi/devices/%s/status", ent->d_name);
        if (access(path, R_OK) == 0) {
            int fd = open(path, O_RDONLY);
            if (fd < 0) {
                printf("[-] Failed to open %s during probe: %s\n", path, strerror(errno));
            } else {
                char buf[256];
                if (read(fd, buf, sizeof(buf)) < 0) {
                    printf("[-] Failed to read %s during probe: %s\n", path, strerror(errno));
                } else {
                    strncpy(acpi_files[num_acpi_files++], path, 256);
                }
                if (close(fd) < 0) {
                    printf("[-] Failed to close %s during probe: %s\n", path, strerror(errno));
                }
            }
        }
        if (num_acpi_files >= MAX_ACPI_DEVS) break;

        snprintf(path, sizeof(path), "/sys/bus/acpi/devices/%s/path", ent->d_name);
        if (access(path, R_OK) == 0) {
            int fd = open(path, O_RDONLY);
            if (fd < 0) {
                printf("[-] Failed to open %s during probe: %s\n", path, strerror(errno));
            } else {
                char buf[256];
                if (read(fd, buf, sizeof(buf)) < 0) {
                    printf("[-] Failed to read %s during probe: %s\n", path, strerror(errno));
                } else {
                    strncpy(acpi_files[num_acpi_files++], path, 256);
                }
                if (close(fd) < 0) {
                    printf("[-] Failed to close %s during probe: %s\n", path, strerror(errno));
                }
            }
        }
        if (num_acpi_files >= MAX_ACPI_DEVS) break;
    }
    
    if (closedir(dir) < 0) {
        printf("[-] Failed to closedir: %s\n", strerror(errno));
        exit(1);
    }
    printf("[+] closedir successful.\n");

    if (num_acpi_files == 0) {
        printf("[-] No readable ACPI status/path files found.\n");
        exit(1);
    }
    printf("[+] Found %d ACPI files to read.\n", num_acpi_files);

    pthread_t threads[8];
    for (int i = 0; i < 8; i++) {
        int res = pthread_create(&threads[i], NULL, acpi_worker, NULL);
        if (res != 0) {
            printf("[-] Failed to pthread_create: %s\n", strerror(res));
            exit(1);
        }
    }
    printf("[+] Threads created successfully.\n");

    for (int i = 0; i < 8; i++) {
        int res = pthread_join(threads[i], NULL);
        if (res != 0) {
            printf("[-] Failed to pthread_join: %s\n", strerror(res));
            exit(1);
        }
    }
    printf("[+] Threads joined successfully.\n");

    sleep(1);
    return 0;
}