dirwalk.c

    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <fcntl.h>
    #include <sys/types.h>
    #include <sys/stat.h>
     
    int read(int fd, char *buf, int n);
    int write(int fd, char *buf, int n);
    int fstat(int fd, struct stat *st);
     
    #define NAME_MAX 14
     
    typedef struct {
        long ino;
        char name[NAME_MAX + 1];
    } Dirent;
     
    typedef struct {
        int fd;
        Dirent d;
    } DIR;
     
    DIR *opendir(char *);
    Dirent *readdir(DIR *);
    void closedir(DIR *);
     
    void fsize(char *);
     
    int main(int argc, char *argv[])
    {
        if (argc == 1)
            fsize(".");
        else
            while (--argc > 0)
                fsize(*++argv);
        return 0;
    }
     
    void dirwalk(char *, void (*)(char *));
     
    void fsize(char *name)
    {
        struct stat stbuf;
     
        if (stat(name, &stbuf) == -1) {
            fprintf(stderr, "fsize: can't access %s\n", name);
            return;
        }
        if ((stbuf.st_mode & S_IFMT) == S_IFDIR) {
            dirwalk(name, fsize);
        }
        printf("%8ld %s\n", stbuf.st_size, name);
    }
     
    #define MAX_PATH 1024
     
    void dirwalk(char *dir, void (*fcn)(char *))
    {
        char name[MAX_PATH];
        Dirent *dp;
        DIR *dfd;
     
        if ((dfd = opendir(dir)) == NULL) {
            fprintf(stderr, "dirwalk: can't open %s\n", dir);
            return;
        }
        while ((dp = readdir(dfd)) != NULL) {
            if (strcmp(dp->name, ".") == 0 || strcmp(dp->name, "..") == 0)
                continue;
            if (strlen(dir) + strlen(dp->name) + 2 > sizeof(name))
                fprintf(stderr, "dirwalk: name %s/%s too long\n", dir, dp->name);
            else {
                sprintf(name, "%s/%s", dir, dp->name);
                (*fcn)(name);
            }
        }
        closedir(dfd);
    }
     
    DIR *opendir(char *dirname)
    {
        int fd;
        struct stat stbuf;
        DIR *dp;
     
        if ((fd = open(dirname, O_RDONLY, 0)) == -1
         || fstat(fd, &stbuf) == -1
         || (stbuf.st_mode & S_IFMT) != S_IFDIR
         || (dp = malloc(sizeof(DIR))) == NULL)
            return NULL;
       dp->fd = fd;
       return dp;
    }
     
    void closedir(DIR *dp)
    {
        if(dp) {
            close(dp->fd);
            free(dp);
        }
    }
    #define DIRSIZ 14
    struct direct
    {
        ino_t d_ino;
        char d_name[DIRSIZ];
    };
     
    Dirent *readdir(DIR *dp)
    {
        struct direct dirbuf;
        static Dirent d;
     
        while ((read(dp->fd, (char *) &dirbuf, sizeof(dirbuf))) != EOF) {
            if (dirbuf.d_ino == 0) {
                continue;
            }
            d.ino = dirbuf.d_ino;
            strncpy(d.name, dirbuf.d_name, DIRSIZ);
            d.name[DIRSIZ] = '\0';
            return &d;
        }
        printf("break");
        return NULL;
    }