rm_u.c

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

#define OPT_RECURSIVE 1
#define OPT_FORCE 2

static int usage()
{
    fprintf(stderr,"Usage: rm [-rRf] <target> [...]\n");
    return -1;
}

/* return -1 on failure, with errno set to the first error */
static int unlink_recursive(const char* name, int flags)
{
    struct stat st;
    DIR *dir;
    struct dirent *de;
    int fail = 0;

    /* is it a file or directory? */
    if(lstat(name, &st) < 0)
        return ((flags & OPT_FORCE) && errno == ENOENT) ? 0 : -1;

    /* a file, so unlink it */
    if(!S_ISDIR(st.st_mode))
        return unlink(name);

    /* a directory, so open handle */
    dir = opendir(name);
    if(dir == NULL)
        return -1;

    /* recurse over components */
    errno = 0;
    while((de = readdir(dir))) {
        char dn[PATH_MAX];
        if (!strcmp(de->d_name, "..") || !strcmp(de->d_name, "."))
            continue;
        sprintf(dn, "%s/%s", name, de->d_name);
        if (unlink_recursive(dn, flags) < 0) {
            fail = 1;
            break;
        }
        errno = 0;
    }
    /* in case readdir or unlink_recursive failed */
    if (fail || errno) {
        int save = errno;
        closedir(dir);
        errno = save;
        return -1;
    }

    /* close directory handle */
    if (closedir(dir) < 0)
        return -1;

    /* delete target directory */
    return rmdir(name);
}

int rm_main(int argc, char *argv[])
{
    int ret;
    int i, c;
    int flags = 0;

    /* check flags */
    while(1) {
        c = getopt(argc, argv, "frR");
        if(c == EOF) break;
        switch (c) {
        case 'f':
            flags |= OPT_FORCE;
            break;
        case 'r':
        case 'R':
            flags |= OPT_RECURSIVE;
            break;
        }
    }

    if(optind < 1 || (optind >= argc && !(flags & OPT_FORCE))) {
        usage();
        return -1;
    }

    /* loop over the file/directory args */
    for(i = optind; i < argc; i++) {
        if(flags & OPT_RECURSIVE) {
            ret = unlink_recursive(argv[i], flags);
        } else {
            ret = unlink(argv[i]);
        }

        if(ret < 0 && (errno != ENOENT || !(flags & OPT_FORCE))) {
            fprintf(stderr, "rm failed for %s, %s\n", argv[i], strerror(errno));
            return -1;
        }
    }

    return 0;
}