commonlib: Add common cbfs parsing logic to coreboot and cbfstool.

To continue sharing more code between the tools and
coreboot proper provide cbfs parsing logic in commonlib.
A cbfs_for_each_file() function was added to allow
one to act on each file found within a cbfs. cbfs_locate()
was updated to use that logic.

BUG=chrome-os-partner:48412
BUG=chromium:445938
BRANCH=None
TEST=Utilized and booted on glados.

Change-Id: I1f23841583e78dc3686f106de9eafe1adbef8c9f
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/12783
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/commonlib/cbfs.c

@@ -0,0 +1,176 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2015 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <console/console.h>
+#include <commonlib/cbfs.h>
+#include <commonlib/endian.h>
+#include <commonlib/helpers.h>
+#include <string.h>
+
+#if !defined(ERROR)
+#define ERROR(x...) printk(BIOS_ERR, "CBFS: " x)
+#endif
+#if !defined(LOG)
+#define LOG(x...) printk(BIOS_INFO, "CBFS: " x)
+#endif
+#if defined(IS_ENABLED)
+
+#if IS_ENABLED(CONFIG_DEBUG_CBFS)
+#define DEBUG(x...) printk(BIOS_SPEW, "CBFS: " x)
+#else
+#define DEBUG(x...)
+#endif
+
+#elif !defined(DEBUG)
+#define DEBUG(x...)
+#endif
+
+static size_t cbfs_next_offset(const struct region_device *cbfs,
+				const struct cbfsf *f)
+{
+	size_t offset;
+
+	if (f == NULL)
+		return 0;
+
+	/* The region_device objects store absolute offets over the whole
+	 * region. Therefore a relative offset needs to be calculated. */
+	offset = rdev_relative_offset(cbfs, &f->data);
+	offset += region_device_sz(&f->data);
+
+	return ALIGN_UP(offset, CBFS_ALIGNMENT);
+}
+
+static int cbfs_end(const struct region_device *cbfs, size_t offset)
+{
+	if (offset >= region_device_sz(cbfs))
+		return 1;
+
+	return 0;
+}
+
+int cbfs_for_each_file(const struct region_device *cbfs,
+			const struct cbfsf *prev, struct cbfsf *fh)
+{
+	size_t offset;
+
+	offset = cbfs_next_offset(cbfs, prev);
+
+	/* Try to scan the entire cbfs region looking for file name. */
+	while (1) {
+		struct cbfs_file file;
+		const size_t fsz = sizeof(file);
+
+		 DEBUG("Checking offset %zx\n", offset);
+
+		/* End of region. */
+		if (cbfs_end(cbfs, offset))
+			return 1;
+
+		/* Can't read file. Nothing else to do but bail out. */
+		if (rdev_readat(cbfs, &file, offset, fsz) != fsz)
+			break;
+
+		if (memcmp(file.magic, CBFS_FILE_MAGIC, sizeof(file.magic))) {
+			offset++;
+			offset = ALIGN_UP(offset, CBFS_ALIGNMENT);
+			continue;
+		}
+
+		file.len = read_be32(&file.len);
+		file.offset = read_be32(&file.offset);
+
+		DEBUG("File @ offset %zx size %x\n", offset, file.len);
+
+		/* Keep track of both the metadata and the data for the file. */
+		if (rdev_chain(&fh->metadata, cbfs, offset, file.offset))
+			break;
+
+		if (rdev_chain(&fh->data, cbfs, offset + file.offset, file.len))
+			break;
+
+		/* Success. */
+		return 0;
+	}
+
+	return -1;
+}
+
+int cbfs_locate(struct cbfsf *fh, const struct region_device *cbfs,
+		const char *name, uint32_t *type)
+{
+	struct cbfsf *prev;
+
+	LOG("Locating '%s'\n", name);
+
+	prev = NULL;
+
+	while (1) {
+		int ret;
+		char *fname;
+		int name_match;
+		const size_t fsz = sizeof(struct cbfs_file);
+
+		ret = cbfs_for_each_file(cbfs, prev, fh);
+		prev = fh;
+
+		/* Either failed to read or hit the end of the region. */
+		if (ret < 0 || ret > 0)
+			break;
+
+		fname = rdev_mmap(&fh->metadata, fsz,
+				region_device_sz(&fh->metadata) - fsz);
+
+		if (fname == NULL)
+			break;
+
+		name_match = !strcmp(fname, name);
+		rdev_munmap(&fh->metadata, fname);
+
+		if (!name_match) {
+			DEBUG(" Unmatched '%s' at %zx\n", fname,
+				rdev_relative_offset(cbfs, &fh->metadata));
+			continue;
+		}
+
+		if (type != NULL) {
+			uint32_t ftype;
+
+			if (rdev_readat(&fh->metadata, &ftype,
+					offsetof(struct cbfs_file, type),
+					sizeof(ftype)) != sizeof(ftype))
+				break;
+
+			ftype = read_be32(&ftype);
+
+			if (*type != ftype) {
+				DEBUG(" Unmatched type %x at %zx\n", ftype,
+					rdev_relative_offset(cbfs,
+							&fh->metadata));
+				continue;
+			}
+		}
+
+		LOG("Found @ offset %zx size %zx\n",
+			rdev_relative_offset(cbfs, &fh->metadata),
+			region_device_sz(&fh->data));
+
+		/* Success. */
+		return 0;
+	}
+
+	LOG("'%s' not found.\n", name);
+	return -1;
+}