1 files changed, 96 insertions, 0 deletions
diff --git a/src/cmd/iochk.c b/src/cmd/iochk.c
new file mode 100644
index 0000000..4483610
--- /dev/null
+++ b/src/cmd/iochk.c
@@ -0,0 +1,96 @@
+#include <assert.h>
+#include <camellia.h>
+#include <camellia/syscalls.h>
+#include <err.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static bool verbose = false;
+
+#define verbosef(...) do { if (verbose) printf(__VA_ARGS__); } while (0)
+
+void check(hid_t h) {
+	const size_t buflen = 4096;
+	const size_t offsets[] = {
+		0, 1, 2, 3, 4, 5, 6, 7,
+		8, 16, 32, 64, 128, 256,
+		512, 1024, 2048,
+	};
+	char *buflast = malloc(buflen);
+	char *bufcur = malloc(buflen);
+	if (!buflast || !bufcur) {
+		err(1, "malloc");
+		goto end;
+	}
+
+	long offlast = 0;
+	long retlast = _sys_read(h, buflast, buflen, offlast);
+	if (retlast < 0) {
+		fprintf(stderr, "error %ld when reading at offset %ld", retlast, offlast);
+		goto end;
+	}
+
+	for (size_t i = 0; i < sizeof(offsets) / sizeof(offsets[0]); i++) {
+		char *tmp;
+		long offcur = offsets[i];
+		long diff = offcur - offlast;
+		assert(diff >= 0);
+		if (retlast < diff) break;
+
+		long retcur = _sys_read(h, bufcur, buflen, offcur);
+		if (retcur < 0) {
+			fprintf(stderr, "error %ld when reading at offset %ld", retlast, offcur);
+			break;
+		}
+		if (retcur < retlast + offlast - offcur) {
+			verbosef("warn: unexpected ret %ld < %ld + %ld - %ld\n", retcur, retlast, offlast, offcur);
+		}
+		if (memcmp(buflast + diff, bufcur, retlast - diff)) {
+			fprintf(stderr, "inconsistent read from offsets %ld and %ld", offlast, offcur);
+		}
+
+		offlast = offcur;
+		retlast = retcur;
+		tmp     = bufcur;
+		bufcur  = buflast;
+		buflast = tmp;
+	}
+
+	// TODO check negative offsets
+
+end:
+	free(buflast);
+	free(bufcur);
+}
+
+int main(int argc, char **argv) {
+	int c;
+	while ((c = getopt(argc, argv, "v")) != -1) {
+		switch (c) {
+			case 'v':
+				verbose = true;
+				break;
+			default:
+				return 1;
+		}
+	}
+	if (optind >= argc) {
+		fprintf(stderr, "usage: iochk [-v] file [files...]\n");
+		return 1;
+	}
+	for (; optind < argc; optind++) {
+		const char *path = argv[optind];
+		verbosef("checking %s...\n", path);
+		hid_t h = camellia_open(path, OPEN_READ);
+		if (h < 0) {
+			err(1, "open %s", path);
+			continue;
+		}
+		check(h);
+		close(h);
+	}
+	return 0;
+}