模拟实现pwd命令

#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <dirent.h>
#include <errno.h>

bool isRoot(const char* path)
{
    if (strcmp(path, "/") == 0)
        return true;

    char pp[256] = {0};

    int l = strlen(path);
    strcpy(pp, path);
    
    if (pp[l - 1] != '/')
    {   
        pp[l] = '/';
        l += 1;
    }   

    strcat(pp, "../");

    struct stat ps; 
    stat(pp, &ps);

    struct stat cs; 
    stat(path, &cs);

    return ps.st_ino   ==  cs.st_ino &&
           ps.st_nlink ==  cs.st_nlink &&
           ps.st_mtime ==  cs.st_mtime;
}

void printPath(const char* path)
{
    if (isRoot(path))
    {
        printf("/");
        return;
    }

    char pp[256] = {0};

    int l = strlen(path);
    strcpy(pp, path);

    if (pp[l - 1] != '/')
    {
        pp[l] = '/';
        l += 1;
    }

    strcat(pp, "../");
    printPath(pp);

    DIR* dp = opendir(pp);
    if (!dp)
    {
        printf("Failed to open dir %s
", pp);
        return;
    }

    struct stat s;
    stat(path, &s);

    char cp[256];
    while (dirent* en = readdir(dp))
    {
        memset(cp, 0, sizeof(cp));
        strcpy(cp, pp);
        strcat(cp, en->d_name);

        struct stat cs;
        stat(cp, &cs);

        if (cs.st_ino == s.st_ino && cs.st_mtime == s.st_mtime)
        {
            printf("%s/", en->d_name);
            break;
        }
    }
}

int main(int argc, char* argv[])
{
    printPath("./");
    printf("
");
    return 0;
}