main.c

   1 #include <sys/stat.h>
   2
   3 #include <err.h>
   4 #define __USE_XOPEN_EXTENDED
   5 #include <ftw.h>
   6 #include <fcntl.h>
   7 #include <libgen.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <time.h>
  12 #include <unistd.h>
  13
  14 #include "util.h"
  15
  16 int verbose = 0;
  17
  18 static char *randstr(size_t len) {
  19     const char *chars = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
  20
  21     char *name;
  22     size_t i;
  23
  24     name = emalloc(len+1);
  25
  26     for (i = 0; i < len; i++) {
  27         name[i] = chars[rand() % strlen(chars)];
  28     }
  29     name[len+1] = '\0';
  30
  31     return name;
  32 }
  33
  34 static char *randren(const char *path) {
  35     unsigned long newpathlen = 0;
  36     unsigned int error = 0;
  37
  38     char *dname, *rname, *pathcopy, *newpath;
  39
  40     /* glibc dirname modifies its argument */
  41     pathcopy = strdup(path);
  42
  43     dname = dirname(pathcopy);
  44
  45     /* Calling pathconf directly on a symlink will return the value for
  46      * the file that it links to or, if it's a dangling symlink, -1
  47      * (failure) so we use the directory it's stored in instead. */
  48     rname = randstr(pathconf(dname, _PC_NAME_MAX));
  49
  50     newpathlen += strlen(dname);
  51     newpathlen += strlen(rname);
  52     newpathlen += 2; /* '/' & '\0' */
  53
  54     newpath = emalloc(newpathlen);
  55
  56     strcpy(newpath, dname);
  57     strcpy(newpath + strlen(newpath), "/");
  58     strcpy(newpath + strlen(newpath), rname);
  59     strcpy(newpath + strlen(newpath), "\0");
  60
  61     /* check whether the file exists */
  62     if (access(newpath, F_OK) == 0) {
  63         warnx("randren: File exists");
  64         error = 1;
  65     } else {
  66         if (rename(path, newpath) == -1) {
  67             warn("randren");
  68             error = 1;
  69         }
  70     }
  71
  72     free(pathcopy);
  73     free(rname);
  74
  75     if (error == 1) {
  76         free(newpath);
  77         return NULL;
  78     } else {
  79         return newpath;
  80     }
  81 }
  82
  83 static int fzero(const char *path) {
  84     ssize_t written = 0;
  85
  86     int fd;
  87     void *buf;
  88     struct stat stbuf;
  89
  90     if (stat(path, &stbuf) == -1) {
  91         warn("fzero");
  92         return -1;
  93     }
  94
  95     buf = emalloc(stbuf.st_blksize);
  96
  97     if ((fd = open(path, O_WRONLY)) == -1) {
  98         warn("fzero");
  99         return -1;
 100     }
 101
 102     while (written < stbuf.st_size) {
 103         written += write(fd, buf, stbuf.st_blksize);
 104     }
 105
 106     fdatasync(fd);
 107
 108     close(fd);
 109     free(buf);
 110
 111     return 0;
 112 }
 113
 114 int can_write(const struct stat *sb) {
 115     uid_t id;
 116
 117     id = geteuid();
 118     if (sb->st_uid == id) {
 119         return 1;
 120     } else {
 121         return 0;
 122     }
 123 }
 124
 125 int fn(const char *fpath, const struct stat *sb, int typeflag,
 126        struct FTW *ftwbuf) {
 127     char *path;
 128
 129     if (!can_write(sb)) {
 130         return 0;
 131     }
 132
 133     path = randren(fpath);
 134     if (path == NULL) {
 135         return 1;
 136     }
 137
 138     switch (typeflag) {
 139         case FTW_SL:
 140             unlink(path);
 141             break;
 142         case FTW_F:
 143             if (fzero(path) != -1) {
 144                 unlink(path);
 145             }
 146             break;
 147         case FTW_DP:
 148             rmdir(path);
 149             break;
 150     }
 151     free(path);
 152
 153     return 0;
 154 }
 155
 156 int main(int argc, char *argv[]) {
 157     int i, c;
 158
 159     while ((c = getopt(argc, argv, "+v")) != -1) {
 160         switch (c) {
 161             case 'v':
 162                 verbose = 1;
 163                 break;
 164         }
 165     }
 166
 167     if (optind == argc) {
 168         fprintf(stderr, "usage: %s [-rv] [file ...]\n", argv[0]);
 169         return 1;
 170     }
 171
 172     srand(time(NULL));
 173
 174     for (i = optind; i < argc; i++) {
 175         nftw(argv[i], fn, 10, FTW_DEPTH | FTW_PHYS);
 176     }
 177
 178     return 0;
 179 }