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39#include "libbb.h"
40
41int shred_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
42int shred_main(int argc UNUSED_PARAM, char **argv)
43{
44 int rand_fd = rand_fd;
45 int zero_fd;
46 unsigned num_iter = 3;
47 unsigned opt;
48 enum {
49 OPT_f = (1 << 0),
50 OPT_u = (1 << 1),
51 OPT_z = (1 << 2),
52 OPT_n = (1 << 3),
53 OPT_v = (1 << 4),
54 OPT_x = (1 << 5),
55 };
56
57 opt = getopt32(argv, "fuzn:+vx", &num_iter);
58 argv += optind;
59
60 zero_fd = xopen("/dev/zero", O_RDONLY);
61 if (num_iter != 0)
62 rand_fd = xopen("/dev/urandom", O_RDONLY);
63
64 if (!*argv)
65 bb_show_usage();
66
67 for (;;) {
68 struct stat sb;
69 const char *fname;
70 unsigned i;
71 int fd;
72
73 fname = *argv++;
74 if (!fname)
75 break;
76 fd = -1;
77 if (opt & OPT_f) {
78 fd = open(fname, O_WRONLY);
79 if (fd < 0)
80 chmod(fname, 0666);
81 }
82 if (fd < 0)
83 fd = xopen(fname, O_WRONLY);
84
85 if (fstat(fd, &sb) == 0 && sb.st_size > 0) {
86 off_t size = sb.st_size;
87
88 for (i = 0; i < num_iter; i++) {
89 bb_copyfd_size(rand_fd, fd, size);
90 fdatasync(fd);
91 xlseek(fd, 0, SEEK_SET);
92 }
93 if (opt & OPT_z) {
94 bb_copyfd_size(zero_fd, fd, size);
95 fdatasync(fd);
96 }
97 if (opt & OPT_u) {
98 ftruncate(fd, 0);
99 xunlink(fname);
100 }
101 xclose(fd);
102 }
103 }
104
105 return EXIT_SUCCESS;
106}
107