bootutil: extracted app common library from bootutil_misc

Part of code of boot/bootutil/ is re-implemented in zephyr-rtos
repository.
As some code are defined here and there it becomes problem when
need to include it with outstanding feature in a build.
It is possible to mitigate problem using #fdefry - but this was
rather temporary hack.

This patch introduce new module which is common for MCUBoot build
and application build.
Common code were extracted to bootutil_public.c source file and
bootutil_public.h header

MCUboot also select DISABLE_MCUBOOT_BOOTUTIL_LIB_OWN_LOG Kconfig
option, as it must define log configuration on its own for all its
sourcecode.

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>
diff --git a/boot/bootutil/src/bootutil_public.c b/boot/bootutil/src/bootutil_public.c
new file mode 100644
index 0000000..f40e1be
--- /dev/null
+++ b/boot/bootutil/src/bootutil_public.c
@@ -0,0 +1,585 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2017-2019 Linaro LTD
+ * Copyright (c) 2016-2019 JUUL Labs
+ * Copyright (c) 2019-2020 Arm Limited
+ * Copyright (c) 2020 Nordic Semiconductor ASA
+ *
+ * Original license:
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+#include <string.h>
+#include <inttypes.h>
+#include <stddef.h>
+
+#include "sysflash/sysflash.h"
+#include "flash_map_backend/flash_map_backend.h"
+
+#include "bootutil/image.h"
+#include "bootutil/bootutil_public.h"
+#include "bootutil_priv.h"
+#include "bootutil/bootutil_log.h"
+#ifdef MCUBOOT_ENC_IMAGES
+#include "bootutil/enc_key.h"
+#endif
+
+#ifdef CONFIG_MCUBOOT
+MCUBOOT_LOG_MODULE_DECLARE(mcuboot);
+#else
+MCUBOOT_LOG_MODULE_REGISTER(mcuboot_util);
+#endif
+
+const uint32_t boot_img_magic[] = {
+    0xf395c277,
+    0x7fefd260,
+    0x0f505235,
+    0x8079b62c,
+};
+
+#define BOOT_MAGIC_ARR_SZ \
+    (sizeof boot_img_magic / sizeof boot_img_magic[0])
+
+struct boot_swap_table {
+    uint8_t magic_primary_slot;
+    uint8_t magic_secondary_slot;
+    uint8_t image_ok_primary_slot;
+    uint8_t image_ok_secondary_slot;
+    uint8_t copy_done_primary_slot;
+
+    uint8_t swap_type;
+};
+
+/**
+ * This set of tables maps image trailer contents to swap operation type.
+ * When searching for a match, these tables must be iterated sequentially.
+ *
+ * NOTE: the table order is very important. The settings in the secondary
+ * slot always are priority to the primary slot and should be located
+ * earlier in the table.
+ *
+ * The table lists only states where there is action needs to be taken by
+ * the bootloader, as in starting/finishing a swap operation.
+ */
+static const struct boot_swap_table boot_swap_tables[] = {
+    {
+        .magic_primary_slot =       BOOT_MAGIC_ANY,
+        .magic_secondary_slot =     BOOT_MAGIC_GOOD,
+        .image_ok_primary_slot =    BOOT_FLAG_ANY,
+        .image_ok_secondary_slot =  BOOT_FLAG_UNSET,
+        .copy_done_primary_slot =   BOOT_FLAG_ANY,
+        .swap_type =                BOOT_SWAP_TYPE_TEST,
+    },
+    {
+        .magic_primary_slot =       BOOT_MAGIC_ANY,
+        .magic_secondary_slot =     BOOT_MAGIC_GOOD,
+        .image_ok_primary_slot =    BOOT_FLAG_ANY,
+        .image_ok_secondary_slot =  BOOT_FLAG_SET,
+        .copy_done_primary_slot =   BOOT_FLAG_ANY,
+        .swap_type =                BOOT_SWAP_TYPE_PERM,
+    },
+    {
+        .magic_primary_slot =       BOOT_MAGIC_GOOD,
+        .magic_secondary_slot =     BOOT_MAGIC_UNSET,
+        .image_ok_primary_slot =    BOOT_FLAG_UNSET,
+        .image_ok_secondary_slot =  BOOT_FLAG_ANY,
+        .copy_done_primary_slot =   BOOT_FLAG_SET,
+        .swap_type =                BOOT_SWAP_TYPE_REVERT,
+    },
+};
+
+#define BOOT_SWAP_TABLES_COUNT \
+    (sizeof boot_swap_tables / sizeof boot_swap_tables[0])
+
+static int
+boot_magic_decode(const uint32_t *magic)
+{
+    if (memcmp(magic, boot_img_magic, BOOT_MAGIC_SZ) == 0) {
+        return BOOT_MAGIC_GOOD;
+    }
+    return BOOT_MAGIC_BAD;
+}
+
+static int
+boot_flag_decode(uint8_t flag)
+{
+    if (flag != BOOT_FLAG_SET) {
+        return BOOT_FLAG_BAD;
+    }
+    return BOOT_FLAG_SET;
+}
+
+static inline uint32_t
+boot_magic_off(const struct flash_area *fap)
+{
+    return fap->fa_size - BOOT_MAGIC_SZ;
+}
+
+static inline uint32_t
+boot_image_ok_off(const struct flash_area *fap)
+{
+    return boot_magic_off(fap) - BOOT_MAX_ALIGN;
+}
+
+static inline uint32_t
+boot_copy_done_off(const struct flash_area *fap)
+{
+    return boot_image_ok_off(fap) - BOOT_MAX_ALIGN;
+}
+
+static inline uint32_t
+boot_swap_size_off(const struct flash_area *fap)
+{
+    return boot_swap_info_off(fap) - BOOT_MAX_ALIGN;
+}
+
+uint32_t
+boot_swap_info_off(const struct flash_area *fap)
+{
+    return boot_copy_done_off(fap) - BOOT_MAX_ALIGN;
+}
+
+/**
+ * Determines if a status source table is satisfied by the specified magic
+ * code.
+ *
+ * @param tbl_val               A magic field from a status source table.
+ * @param val                   The magic value in a trailer, encoded as a
+ *                                  BOOT_MAGIC_[...].
+ *
+ * @return                      1 if the two values are compatible;
+ *                              0 otherwise.
+ */
+int
+boot_magic_compatible_check(uint8_t tbl_val, uint8_t val)
+{
+    switch (tbl_val) {
+    case BOOT_MAGIC_ANY:
+        return 1;
+
+    case BOOT_MAGIC_NOTGOOD:
+        return val != BOOT_MAGIC_GOOD;
+
+    default:
+        return tbl_val == val;
+    }
+}
+
+#ifdef MCUBOOT_ENC_IMAGES
+static inline uint32_t
+boot_enc_key_off(const struct flash_area *fap, uint8_t slot)
+{
+#if MCUBOOT_SWAP_SAVE_ENCTLV
+    return boot_swap_size_off(fap) - ((slot + 1) *
+            ((((BOOT_ENC_TLV_SIZE - 1) / BOOT_MAX_ALIGN) + 1) * BOOT_MAX_ALIGN));
+#else
+    return boot_swap_size_off(fap) - ((slot + 1) * BOOT_ENC_KEY_SIZE);
+#endif
+}
+#endif
+
+bool bootutil_buffer_is_erased(const struct flash_area *area,
+                               const void *buffer, size_t len)
+{
+    size_t i;
+    uint8_t *u8b;
+    uint8_t erased_val;
+
+    if (buffer == NULL || len == 0) {
+        return false;
+    }
+
+    erased_val = flash_area_erased_val(area);
+    for (i = 0, u8b = (uint8_t *)buffer; i < len; i++) {
+        if (u8b[i] != erased_val) {
+            return false;
+        }
+    }
+
+    return true;
+}
+
+int
+boot_read_swap_state(const struct flash_area *fap,
+                     struct boot_swap_state *state)
+{
+    uint32_t magic[BOOT_MAGIC_ARR_SZ];
+    uint32_t off;
+    uint8_t swap_info;
+    int rc;
+
+    off = boot_magic_off(fap);
+    rc = flash_area_read(fap, off, magic, BOOT_MAGIC_SZ);
+    if (rc < 0) {
+        return BOOT_EFLASH;
+    }
+    if (bootutil_buffer_is_erased(fap, magic, BOOT_MAGIC_SZ)) {
+        state->magic = BOOT_MAGIC_UNSET;
+    } else {
+        state->magic = boot_magic_decode(magic);
+    }
+
+    off = boot_swap_info_off(fap);
+    rc = flash_area_read(fap, off, &swap_info, sizeof swap_info);
+    if (rc < 0) {
+        return BOOT_EFLASH;
+    }
+
+    /* Extract the swap type and image number */
+    state->swap_type = BOOT_GET_SWAP_TYPE(swap_info);
+    state->image_num = BOOT_GET_IMAGE_NUM(swap_info);
+
+    if (bootutil_buffer_is_erased(fap, &swap_info, sizeof swap_info) ||
+            state->swap_type > BOOT_SWAP_TYPE_REVERT) {
+        state->swap_type = BOOT_SWAP_TYPE_NONE;
+        state->image_num = 0;
+    }
+
+    off = boot_copy_done_off(fap);
+    rc = flash_area_read(fap, off, &state->copy_done, sizeof state->copy_done);
+    if (rc < 0) {
+        return BOOT_EFLASH;
+    }
+    if (bootutil_buffer_is_erased(fap, &state->copy_done,
+                sizeof state->copy_done)) {
+        state->copy_done = BOOT_FLAG_UNSET;
+    } else {
+        state->copy_done = boot_flag_decode(state->copy_done);
+    }
+
+    off = boot_image_ok_off(fap);
+    rc = flash_area_read(fap, off, &state->image_ok, sizeof state->image_ok);
+    if (rc < 0) {
+        return BOOT_EFLASH;
+    }
+    if (bootutil_buffer_is_erased(fap, &state->image_ok,
+                sizeof state->image_ok)) {
+        state->image_ok = BOOT_FLAG_UNSET;
+    } else {
+        state->image_ok = boot_flag_decode(state->image_ok);
+    }
+
+    return 0;
+}
+
+/**
+ * Reads the image trailer from the scratch area.
+ */
+int
+boot_read_swap_state_by_id(int flash_area_id, struct boot_swap_state *state)
+{
+    const struct flash_area *fap;
+    int rc;
+
+    rc = flash_area_open(flash_area_id, &fap);
+    if (rc != 0) {
+        return BOOT_EFLASH;
+    }
+
+    rc = boot_read_swap_state(fap, state);
+    flash_area_close(fap);
+    return rc;
+}
+
+int
+boot_write_magic(const struct flash_area *fap)
+{
+    uint32_t off;
+    int rc;
+
+    off = boot_magic_off(fap);
+
+    BOOT_LOG_DBG("writing magic; fa_id=%d off=0x%lx (0x%lx)",
+                 fap->fa_id, (unsigned long)off,
+                 (unsigned long)(fap->fa_off + off));
+    rc = flash_area_write(fap, off, boot_img_magic, BOOT_MAGIC_SZ);
+    if (rc != 0) {
+        return BOOT_EFLASH;
+    }
+
+    return 0;
+}
+
+/**
+ * Write trailer data; status bytes, swap_size, etc
+ *
+ * @returns 0 on success, != 0 on error.
+ */
+static int
+boot_write_trailer(const struct flash_area *fap, uint32_t off,
+        const uint8_t *inbuf, uint8_t inlen)
+{
+    uint8_t buf[BOOT_MAX_ALIGN];
+    uint8_t align;
+    uint8_t erased_val;
+    int rc;
+
+    align = flash_area_align(fap);
+    if (inlen > BOOT_MAX_ALIGN || align > BOOT_MAX_ALIGN) {
+        return -1;
+    }
+    erased_val = flash_area_erased_val(fap);
+    if (align < inlen) {
+        align = inlen;
+    }
+    memcpy(buf, inbuf, inlen);
+    memset(&buf[inlen], erased_val, align - inlen);
+
+    rc = flash_area_write(fap, off, buf, align);
+    if (rc != 0) {
+        return BOOT_EFLASH;
+    }
+
+    return 0;
+}
+
+static int
+boot_write_trailer_flag(const struct flash_area *fap, uint32_t off,
+        uint8_t flag_val)
+{
+    const uint8_t buf[1] = { flag_val };
+    return boot_write_trailer(fap, off, buf, 1);
+}
+
+int
+boot_write_image_ok(const struct flash_area *fap)
+{
+    uint32_t off;
+
+    off = boot_image_ok_off(fap);
+    BOOT_LOG_DBG("writing image_ok; fa_id=%d off=0x%lx (0x%lx)",
+                 fap->fa_id, (unsigned long)off,
+                 (unsigned long)(fap->fa_off + off));
+    return boot_write_trailer_flag(fap, off, BOOT_FLAG_SET);
+}
+
+/**
+ * Writes the specified value to the `swap-type` field of an image trailer.
+ * This value is persisted so that the boot loader knows what swap operation to
+ * resume in case of an unexpected reset.
+ */
+int
+boot_write_swap_info(const struct flash_area *fap, uint8_t swap_type,
+                     uint8_t image_num)
+{
+    uint32_t off;
+    uint8_t swap_info;
+
+    BOOT_SET_SWAP_INFO(swap_info, image_num, swap_type);
+    off = boot_swap_info_off(fap);
+    BOOT_LOG_DBG("writing swap_info; fa_id=%d off=0x%lx (0x%lx), swap_type=0x%x"
+                 " image_num=0x%x",
+                 fap->fa_id, (unsigned long)off,
+                 (unsigned long)(fap->fa_off + off), swap_type, image_num);
+    return boot_write_trailer(fap, off, (const uint8_t *) &swap_info, 1);
+}
+
+int
+boot_swap_type_multi(int image_index)
+{
+    const struct boot_swap_table *table;
+    struct boot_swap_state primary_slot;
+    struct boot_swap_state secondary_slot;
+    int rc;
+    size_t i;
+
+    rc = boot_read_swap_state_by_id(FLASH_AREA_IMAGE_PRIMARY(image_index),
+                                    &primary_slot);
+    if (rc) {
+        return BOOT_SWAP_TYPE_PANIC;
+    }
+
+    rc = boot_read_swap_state_by_id(FLASH_AREA_IMAGE_SECONDARY(image_index),
+                                    &secondary_slot);
+    if (rc) {
+        return BOOT_SWAP_TYPE_PANIC;
+    }
+
+    for (i = 0; i < BOOT_SWAP_TABLES_COUNT; i++) {
+        table = boot_swap_tables + i;
+
+        if (boot_magic_compatible_check(table->magic_primary_slot,
+                                        primary_slot.magic) &&
+            boot_magic_compatible_check(table->magic_secondary_slot,
+                                        secondary_slot.magic) &&
+            (table->image_ok_primary_slot == BOOT_FLAG_ANY   ||
+                table->image_ok_primary_slot == primary_slot.image_ok) &&
+            (table->image_ok_secondary_slot == BOOT_FLAG_ANY ||
+                table->image_ok_secondary_slot == secondary_slot.image_ok) &&
+            (table->copy_done_primary_slot == BOOT_FLAG_ANY  ||
+                table->copy_done_primary_slot == primary_slot.copy_done)) {
+            BOOT_LOG_INF("Swap type: %s",
+                         table->swap_type == BOOT_SWAP_TYPE_TEST   ? "test"   :
+                         table->swap_type == BOOT_SWAP_TYPE_PERM   ? "perm"   :
+                         table->swap_type == BOOT_SWAP_TYPE_REVERT ? "revert" :
+                         "BUG; can't happen");
+            if (table->swap_type != BOOT_SWAP_TYPE_TEST &&
+                    table->swap_type != BOOT_SWAP_TYPE_PERM &&
+                    table->swap_type != BOOT_SWAP_TYPE_REVERT) {
+                return BOOT_SWAP_TYPE_PANIC;
+            }
+            return table->swap_type;
+        }
+    }
+
+    BOOT_LOG_INF("Swap type: none");
+    return BOOT_SWAP_TYPE_NONE;
+}
+
+/*
+ * This function is not used by the bootloader itself, but its required API
+ * by external tooling like mcumgr.
+ */
+int
+boot_swap_type(void)
+{
+    return boot_swap_type_multi(0);
+}
+
+/**
+ * Marks the image in the secondary slot as pending.  On the next reboot,
+ * the system will perform a one-time boot of the the secondary slot image.
+ *
+ * @param permanent         Whether the image should be used permanently or
+ *                              only tested once:
+ *                                  0=run image once, then confirm or revert.
+ *                                  1=run image forever.
+ *
+ * @return                  0 on success; nonzero on failure.
+ */
+int
+boot_set_pending(int permanent)
+{
+    const struct flash_area *fap;
+    struct boot_swap_state state_secondary_slot;
+    uint8_t swap_type;
+    int rc;
+
+    rc = boot_read_swap_state_by_id(FLASH_AREA_IMAGE_SECONDARY(0),
+                                    &state_secondary_slot);
+    if (rc != 0) {
+        return rc;
+    }
+
+    switch (state_secondary_slot.magic) {
+    case BOOT_MAGIC_GOOD:
+        /* Swap already scheduled. */
+        return 0;
+
+    case BOOT_MAGIC_UNSET:
+        rc = flash_area_open(FLASH_AREA_IMAGE_SECONDARY(0), &fap);
+        if (rc != 0) {
+            rc = BOOT_EFLASH;
+        } else {
+            rc = boot_write_magic(fap);
+        }
+
+        if (rc == 0 && permanent) {
+            rc = boot_write_image_ok(fap);
+        }
+
+        if (rc == 0) {
+            if (permanent) {
+                swap_type = BOOT_SWAP_TYPE_PERM;
+            } else {
+                swap_type = BOOT_SWAP_TYPE_TEST;
+            }
+            rc = boot_write_swap_info(fap, swap_type, 0);
+        }
+
+        flash_area_close(fap);
+        return rc;
+
+    case BOOT_MAGIC_BAD:
+        /* The image slot is corrupt.  There is no way to recover, so erase the
+         * slot to allow future upgrades.
+         */
+        rc = flash_area_open(FLASH_AREA_IMAGE_SECONDARY(0), &fap);
+        if (rc != 0) {
+            return BOOT_EFLASH;
+        }
+
+        flash_area_erase(fap, 0, fap->fa_size);
+        flash_area_close(fap);
+        return BOOT_EBADIMAGE;
+
+    default:
+        assert(0);
+        return BOOT_EBADIMAGE;
+    }
+}
+
+/**
+ * Marks the image in the primary slot as confirmed.  The system will continue
+ * booting into the image in the primary slot until told to boot from a
+ * different slot.
+ *
+ * @return                  0 on success; nonzero on failure.
+ */
+int
+boot_set_confirmed(void)
+{
+    const struct flash_area *fap;
+    struct boot_swap_state state_primary_slot;
+    int rc;
+
+    rc = boot_read_swap_state_by_id(FLASH_AREA_IMAGE_PRIMARY(0),
+                                    &state_primary_slot);
+    if (rc != 0) {
+        return rc;
+    }
+
+    switch (state_primary_slot.magic) {
+    case BOOT_MAGIC_GOOD:
+        /* Confirm needed; proceed. */
+        break;
+
+    case BOOT_MAGIC_UNSET:
+        /* Already confirmed. */
+        return 0;
+
+    case BOOT_MAGIC_BAD:
+        /* Unexpected state. */
+        return BOOT_EBADVECT;
+    }
+
+    rc = flash_area_open(FLASH_AREA_IMAGE_PRIMARY(0), &fap);
+    if (rc) {
+        rc = BOOT_EFLASH;
+        goto done;
+    }
+
+    if (state_primary_slot.copy_done == BOOT_FLAG_UNSET) {
+        /* Swap never completed.  This is unexpected. */
+        rc = BOOT_EBADVECT;
+        goto done;
+    }
+
+    if (state_primary_slot.image_ok != BOOT_FLAG_UNSET) {
+        /* Already confirmed. */
+        goto done;
+    }
+
+    rc = boot_write_image_ok(fap);
+
+done:
+    flash_area_close(fap);
+    return rc;
+}