+#include "lib.h"
+
+static int status = 0;
+static unsigned flags = 0;
+#define F_FIX 1u
+
+static void vgripe_syserr(int st, int err, const char *fmt, va_list ap)
+ { vmoan_syserr(err, fmt, ap); if (st > status) status = st; }
+static void vgripe(int st, const char *fmt, va_list ap)
+ { vgripe_syserr(st, 0, fmt, ap); }
+PRINTF_LIKE(3, 4)
+ static void gripe_syserr(int st, int err, const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt); vgripe_syserr(st, err, fmt, ap); va_end(ap);
+}
+PRINTF_LIKE(2, 3) static void gripe(int st, const char *fmt, ...)
+ { va_list ap; va_start(ap, fmt); vgripe(st, fmt, ap); va_end(ap); }
+
+static int carefully_read(int fd, off_t off,
+ void *p, size_t sz, const char *file)
+{
+ ssize_t n;
+ char *q = p;
+
+ if (lseek(fd, off, SEEK_SET) < 0)
+ { gripe_syserr(2, errno, "failed to seek in `%s'", file); return (-1); }
+
+ while (sz) {
+ n = read(fd, q, sz);
+ if (n < 0)
+ { gripe_syserr(2, errno, "failed to read `%s'", file); return (-1); }
+ else if (!n)
+ { gripe(2, "unexpected end-of-file reading `%s'", file); return (-1); }
+ q += n; sz -= n;
+ }
+ return (0);
+}
+
+typedef uint_least32_t u32;
+#define Pu32 PRIuLEAST32
+
+static u32 load32(const unsigned char *p)
+{
+ return (((u32)p[0] << 0) | ((u32)p[1] << 8) |
+ ((u32)p[2] << 16) | ((u32)p[3] << 24));
+}
+
+#define CAHF_GRIPE 1u
+#define CAHF_FULL 1u
+static int check_anchor_header(const unsigned char *b, secaddr addr,
+ unsigned f, const char *file)
+{
+ unsigned i, t;
+ secaddr n;
+
+ if (b[0] != 2) {
+ if (f&CAHF_GRIPE)
+ gripe(1, "anchor descriptor not found at `%s' sector %"PRIuSEC"",
+ file, addr);
+ return (-1);
+ }
+
+ for (i = 0, t = 0; i < 16; i++) if (i != 4) t += b[i];
+ t %= 256;
+ if (b[4] != t) {
+ if (f&CAHF_GRIPE)
+ gripe(1, "bad anchor descriptor header checksum (%u /= %u) "
+ "at `%s' sector %"PRIuSEC"", (unsigned)b[4], t, file, addr);
+ return (-1);
+ }
+
+ if (f&CAHF_FULL) {
+ n = load32(b + 12);
+ if (n != addr) {
+ if (f&CAHF_GRIPE)
+ gripe(1, "bad sector number in anchor descriptor "
+ "(%"PRIuSEC" /= %"PRIuSEC") in `%s'",
+ n, addr, file);
+ return (-1);
+ }
+ }
+
+ return (0);
+}
+
+static int all_zero_p(const unsigned char *p, size_t sz)
+{
+ while (sz) {
+ if (*p) return (0);
+ p++; sz--;
+ }
+ return (1);
+}
+
+static void check_img(const char *file)
+{
+ int fd = -1;
+ struct stat st;
+ unsigned char b[SECTORSZ], bb[SECTORSZ];
+ secaddr end;
+ unsigned i, j;
+
+ fd = open(file, (flags&F_FIX) ? O_RDWR : O_RDONLY);
+ if (fd < 0)
+ { gripe_syserr(2, errno, "failed to open `%s'", file); goto end; }
+ if (fstat(fd, &st)) {
+ gripe_syserr(2, errno, "failed to retrieve file status for `%s'", file);
+ goto end;
+ }
+ if (st.st_size%SECTORSZ) {
+ gripe(2, "bad length for `%s' -- not whole number of sectors", file);
+ goto end;
+ }
+ end = st.st_size/SECTORSZ;
+
+ if (carefully_read(fd, 256*SECTORSZ, b, SECTORSZ, file) ||
+ check_anchor_header(b, 256, CAHF_GRIPE | CAHF_FULL, file))
+ goto end;
+
+ for (i = 1; i < 32768; i++) {
+ if (carefully_read(fd, (off_t)(end - i)*SECTORSZ, bb, SECTORSZ, file))
+ goto end;
+ if (bb[0] || !all_zero_p(bb, SECTORSZ)) goto nonzero;
+ }
+ gripe(1, "too many trailing zero sectors: "
+ "couldn't find backup anchor descriptor");
+ goto end;
+nonzero:
+ j = i;
+ for (;;) {
+ if (bb[0] == 2 && !check_anchor_header(bb, end - j, 0, file))
+ break;
+ j++;
+ if (j > i + 256) {
+ gripe(1, "failed to find backup anchor descriptor in `%s'", file);
+ goto end;
+ }
+ if (carefully_read(fd, (off_t)(end - j)*SECTORSZ, bb, SECTORSZ, file))
+ goto end;
+ }
+ if (j > i) {
+ gripe(1, "found backup anchor descriptor at sector %"PRIuSEC" "
+ " = %"PRIuSEC" from end, = %"PRIuSEC" from trailing zeros",
+ end - j, j, j - i + 1);
+ i = j;
+ }
+
+ if (check_anchor_header(bb, end - i, CAHF_GRIPE | CAHF_FULL, file))
+ goto end;
+
+ if (MEMCMP(b + 16, != , bb + 16, SECTORSZ - 16)) {
+ gripe(1, "backup anchor descriptor in sector %"PRIuSEC" "
+ "doesn't match primary in sector 256 of `%s'",
+ end - i, file);
+ goto end;
+ }
+
+ if (i > 1) {
+ if (!(flags&F_FIX))
+ gripe(1, "%u trailing zero sectors in `%s'", i - 1, file);
+ else {
+ if (ftruncate(fd, (off_t)(end - i + 1)*SECTORSZ))
+ gripe_syserr(2, errno,
+ "failed to truncate `%s' to %"PRIuSEC" sectors",
+ file, end - i + 1);
+ else
+ moan("removed %u trailing zero sectors from `%s'", i - 1, file);
+ }
+ }
+
+end:
+ if (fd != -1) close(fd);
+}
+
+static void usage(FILE *fp)
+ { fprintf(fp, "usage: %s [-x] IMG ...\n", prog); }
+
+int main(int argc, char *argv[])
+{
+ int i, opt;
+ unsigned f = 0;
+#define f_bogus 1u
+
+ set_prog(argv[0]);
+ for (;;) {
+ opt = getopt(argc, argv, "hx"); if (opt < 0) break;
+ switch (opt) {
+ case 'h': usage(stdout); exit(0);
+ case 'x': flags |= F_FIX; break;
+ default: f |= f_bogus; break;
+ }
+ }
+ if (optind >= argc) f |= f_bogus;
+ if (f&f_bogus) { usage(stderr); exit(2); }
+
+ for (i = optind; i < argc; i++) check_img(argv[i]);
+ return (status);
+}
~mdw / dvdrip / commitdiff