First commit

Signed-off-by: Mattias Andrée <maandree@kth.se>

6 files changed, 315 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..a0cae35
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+*\#*
+*~
+*.o
+*.a
+*.lo
+*.su
+*.so
+*.so.*
+*.dll
+*.dylib
+*.gch
+*.gcov
+*.gcno
+*.gcda
+/deadshred
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..fccd785
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,15 @@
+ISC License
+
+© 2024 Mattias Andrée <maandree@kth.se>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..1e91bbd
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,37 @@
+.POSIX:
+
+CONFIGFILE = config.mk
+include $(CONFIGFILE)
+
+OBJ =\
+	deadshred.o
+
+HDR =
+
+all: deadshred
+$(OBJ): $(HDR)
+
+.c.o:
+	$(CC) -c -o $@ $< $(CFLAGS) $(CPPFLAGS)
+
+deadshred: $(OBJ)
+	$(CC) -o $@ $(OBJ) $(LDFLAGS)
+
+install: deadshred
+	mkdir -p -- "$(DESTDIR)$(PREFIX)/bin"
+	mkdir -p -- "$(DESTDIR)$(MANPREFIX)/man1/"
+	cp -- deadshred "$(DESTDIR)$(PREFIX)/bin/"
+	cp -- deadshred.1 "$(DESTDIR)$(MANPREFIX)/man1/"
+
+uninstall:
+	-rm -f -- "$(DESTDIR)$(PREFIX)/bin/deadshred"
+	-rm -f -- "$(DESTDIR)$(MANPREFIX)/man1/deadshred.1"
+
+clean:
+	-rm -f -- *.o *.a *.lo *.su *.so *.so.* *.gch *.gcov *.gcno *.gcda
+	-rm -f -- deadshred
+
+.SUFFIXES:
+.SUFFIXES: .o .c
+
+.PHONY: all install uninstall clean
diff --git a/TODO b/TODO
new file mode 100644
index 0000000..1aede57
--- /dev/null
+++ b/TODO
@@ -0,0 +1,9 @@
+Add README
+Add man page
+Add `-n iterations`
+Add shred map for continuing later (print to stdout on SIGTERM)
+
+Enhance progress printout with:
+	exact bytes count
+	bad sections (count, bytes)
+	shredded bytes per seconds
diff --git a/config.mk b/config.mk
new file mode 100644
index 0000000..aeb8cec
--- /dev/null
+++ b/config.mk
@@ -0,0 +1,8 @@
+PREFIX    = /usr
+MANPREFIX = $(PREFIX)/share/man
+
+CC = c99
+
+CPPFLAGS = -D_DEFAULT_SOURCE -D_BSD_SOURCE -D_XOPEN_SOURCE=700 -D_GNU_SOURCE
+CFLAGS   =
+LDFLAGS  = -lsimple
diff --git a/deadshred.c b/deadshred.c
new file mode 100644
index 0000000..5323d15
--- /dev/null
+++ b/deadshred.c
@@ -0,0 +1,231 @@
+/* See LICENSE file for copyright and license details. */
+#include <sys/mount.h>
+#include <libsimple.h>
+#include <libsimple-arg.h>
+
+
+USAGE("file");
+
+
+struct span {
+	off_t start;
+	off_t end;
+	size_t blocksize;
+};
+
+
+static struct span *spans = NULL;
+static size_t nspans = 0;
+static size_t spans_size = 0;
+
+static off_t shredded = 0;
+static off_t total_size = 0;
+
+static char reservoir[128U << 10];
+static size_t reservoir_off = sizeof(reservoir);
+
+static char total_size_1000[256];
+static char total_size_1024[256];
+
+
+static off_t
+filesize(int fd, const char *fname)
+{
+	struct stat st;
+
+	if (fstat(fd, &st))
+		eprintf("fstat %s:", fname);
+
+	switch (st.st_mode & S_IFMT) {
+	case S_IFREG:
+		break;
+	case S_IFBLK:
+		if (ioctl(fd, BLKGETSIZE64, &st.st_size) < 0)
+			eprintf("ioctl %s BLKGETSIZE64:", fname);
+		break;
+	default:
+		eprintf("%s: not a regular file or block device", fname);
+	}
+
+	return st.st_size;
+}
+
+
+static void
+ensure_random(size_t needed)
+{
+	size_t off;
+	ssize_t r;
+
+	if (sizeof(reservoir) - reservoir_off >= needed)
+		return;
+
+	for (off = 0; off < reservoir_off;) {
+		r = read(STDIN_FILENO, &reservoir[off], reservoir_off - off);
+		if (r <= 0) {
+			if (!r)
+				eprintf("random source depleted");
+			if (errno == EINTR)
+				continue;
+			eprintf("read <stdin>:");
+		}
+		off += (size_t)r;
+	}
+
+	reservoir_off = 0;
+}
+
+
+static off_t
+add_span(off_t off, off_t max_end, size_t blocksize)
+{
+	off_t end;
+
+	end = MIN((off | ((off_t)blocksize - 1)) + 1, max_end);
+	while ((off_t)(blocksize >> 1) >= end - off)
+		blocksize >>= 1;
+
+	if (nspans == spans_size) {
+		spans_size += 1024;
+		spans = ereallocarray(spans, spans_size, sizeof(*spans));
+	}
+
+	spans[nspans].start = off;
+	spans[nspans].end = end;
+	spans[nspans].blocksize = (size_t)blocksize;
+	nspans++;
+}
+
+
+static char *
+humansize1000(off_t s, char *buf)
+{
+	const char *units = "kMGTPEZYRQ";
+	size_t unit = 0;
+	if (s < 1000) {
+		sprintf(buf, "%u B", (unsigned)s);
+		return buf;
+	}
+	s /= 100;
+	while (units[unit + 1U] && s >= 10000) {
+		s /= 1000;
+		unit++;
+	}
+	sprintf(buf, "%u.%u %cB", (unsigned)s / 10U, (unsigned)s % 10U, units[unit]);
+	return buf;
+}
+
+
+static char *
+humansize1024(off_t s, char *buf)
+{
+	const char *units = "KMGTPEZYRQ";
+	size_t unit = 0;
+	if (s < 1024) {
+		sprintf(buf, "%u B", (unsigned)s);
+		return buf;
+	}
+	while (units[unit + 1U] && s >= 1024 * 1024) {
+		s /= 1024;
+		unit++;
+	}
+	sprintf(buf, "%lu.%u %ciB", (unsigned long int)s / 1024U, (unsigned long int)((s * 10 % 10240) / 1024U), units[unit]);
+	return buf;
+}
+
+
+static int
+print_progress(int done)
+{
+	static char buf1[1024] = {0};
+	static char buf2[1024] = {0};
+	static int i = 0;
+
+	char subbuf1[256];
+	char subbuf2[256];
+
+	sprintf(i == 0 ? buf1 : buf2,
+	        "%.2lf %% (%s, %s) of %s (%s) shredded\033[K\n%s",
+	        100. * (double)shredded / (double)total_size,
+	        humansize1000(shredded, subbuf1),
+	        humansize1024(shredded, subbuf2),
+	        total_size_1000,
+	        total_size_1024,
+	        done ? "" : "\033[A");
+
+	if (strcmp(buf1, buf2)) {
+		fprintf(stderr, "%s", i == 0 ? buf1 : buf2);
+		fflush(stderr);
+	}
+
+	i ^= 1;
+}
+
+
+static void
+shredspan(int fd, const struct span *span, const char *fname)
+{
+	off_t off;
+	ssize_t r;
+
+	for (off = span->start; off < span->end;) {
+		print_progress(0);
+		if (lseek(fd, off, SEEK_SET) < 0)
+			eprintf("lseek %s %ji SEEK_SET\n", fname, (intmax_t)off);
+		ensure_random(span->blocksize);
+		r = write(fd, &reservoir[reservoir_off], (size_t)MIN((off_t)span->blocksize, span->end - off));
+		if (r < 0) {
+			if (errno != EINTR)
+				off = add_span(off, span->end, span->blocksize == 1U ? 1U : span->blocksize);
+			continue;
+		}
+		off += (off_t)r;
+		shredded += (off_t)r;
+		reservoir_off += (size_t)r;
+	}
+}
+
+
+int
+main(int argc, char *argv[])
+{
+	char buf1[256];
+	char buf2[256];
+	size_t i;
+	int fd;
+
+	ARGBEGIN {
+	default:
+		usage();
+	} ARGEND;
+
+	if (argc != 1)
+		usage();
+
+	fd = open(argv[0], O_WRONLY);
+	if (fd < 0)
+		eprintf("open %s O_WRONLY:", argv[0]);
+
+	spans = emalloc(sizeof(*spans));
+	spans[0].start = 0;
+	spans[0].end = total_size = filesize(fd, argv[0]);
+	spans[0].blocksize = 8192U;
+	nspans = 1U;
+	spans_size = 1U;
+
+	humansize1000(total_size, total_size_1000);
+	humansize1024(total_size, total_size_1024);
+
+	while (nspans) {
+		size_t old_nspans = nspans;
+		for (i = 0; i < old_nspans; i++)
+			shredspan(fd, &spans[i], argv[0]);
+		nspans -= old_nspans;
+		memmove(&spans[0], &spans[old_nspans], nspans * sizeof(*spans));
+	}
+
+	close(fd);
+
+	print_progress(1);
+	return 0;
+}