Problem - Kevin Tafuro

}
fsync(fd);
return 0;
}
static int pattern_pass(int fd, unsigned char *buf, size_t bufsz, size_t filesz) {
size_t towrite;
if (!bufsz || lseek(fd, 0, SEEK_SET) != 0) return -1;
while (filesz > 0) {
towrite = (filesz > bufsz ? bufsz : filesz);
if (!write_data(fd, buf, towrite)) return -1;
filesz -= towrite;
}
fsync(fd);
return 0;
}
int spc_fd_wipe(int fd) {
int count, i, pass, patternsz;
struct stat st;
unsigned char buf[SPC_WIPE_BUFSIZE], *pattern;
static unsigned char single_pats[16] = {
0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,
0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
};
static unsigned char triple_pats[6][3] = {
{ 0x92, 0x49, 0x24 }, { 0x49, 0x24, 0x92 }, { 0x24, 0x92, 0x49 },
{ 0x6d, 0xb6, 0xdb }, { 0xb6, 0xdb, 0x6d }, { 0xdb, 0x6d, 0xb6 }
};
if (fstat(fd, &st) = = -1) return -1;
if (!st.st_size) return 0;
for (pass = 0; pass < 4; pass++)
if (random_pass(fd, st.st_size) = = -1) return -1;
memset(buf, single_pats[5], sizeof(buf));
if (pattern_pass(fd, buf, sizeof(buf), st.st_size) = = -1) return -1;
memset(buf, single_pats[10], sizeof(buf));
if (pattern_pass(fd, buf, sizeof(buf), st.st_size) = = -1) return -1;
patternsz = sizeof(triple_pats[0]);
for (pass = 0; pass < 3; pass++) {
pattern = triple_pats[pass];
count = sizeof(buf) / patternsz;
for (i = 0; i < count; i++)
memcpy(buf + (i * patternsz), pattern, patternsz);
if (pattern_pass(fd, buf, patternsz * count, st.st_size) = = -1) return -1;
}
for (pass = 0; pass < sizeof(single_pats); pass++) {
memset(buf, single_pats[pass], sizeof(buf));
50 | Chapter 2: Access Control
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