main.c
// SPDX-License-Identifier: GPL-2.0
/*
* Boot config tool for initrd image
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <endian.h>
#include <linux/bootconfig.h>
#define pr_err(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)
static int xbc_show_value(struct xbc_node *node, bool semicolon)
{
const char *val, *eol;
char q;
int i = 0;
eol = semicolon ? ";\n" : "\n";
xbc_array_for_each_value(node, val) {
if (strchr(val, '"'))
q = '\'';
else
q = '"';
printf("%c%s%c%s", q, val, q, xbc_node_is_array(node) ? ", " : eol);
i++;
}
return i;
}
static void xbc_show_compact_tree(void)
{
struct xbc_node *node, *cnode = NULL, *vnode;
int depth = 0, i;
node = xbc_root_node();
while (node && xbc_node_is_key(node)) {
for (i = 0; i < depth; i++)
printf("\t");
if (!cnode)
cnode = xbc_node_get_child(node);
while (cnode && xbc_node_is_key(cnode) && !cnode->next) {
vnode = xbc_node_get_child(cnode);
/*
* If @cnode has value and subkeys, this
* should show it as below.
*
* key(@node) {
* key(@cnode) = value;
* key(@cnode) {
* subkeys;
* }
* }
*/
if (vnode && xbc_node_is_value(vnode) && vnode->next)
break;
printf("%s.", xbc_node_get_data(node));
node = cnode;
cnode = vnode;
}
if (cnode && xbc_node_is_key(cnode)) {
printf("%s {\n", xbc_node_get_data(node));
depth++;
node = cnode;
cnode = NULL;
continue;
} else if (cnode && xbc_node_is_value(cnode)) {
printf("%s = ", xbc_node_get_data(node));
xbc_show_value(cnode, true);
/*
* If @node has value and subkeys, continue
* looping on subkeys with same node.
*/
if (cnode->next) {
cnode = xbc_node_get_next(cnode);
continue;
}
} else {
printf("%s;\n", xbc_node_get_data(node));
}
cnode = NULL;
if (node->next) {
node = xbc_node_get_next(node);
continue;
}
while (!node->next) {
node = xbc_node_get_parent(node);
if (!node)
return;
if (!xbc_node_get_child(node)->next)
continue;
if (depth) {
depth--;
for (i = 0; i < depth; i++)
printf("\t");
printf("}\n");
}
}
node = xbc_node_get_next(node);
}
}
static void xbc_show_list(void)
{
char key[XBC_KEYLEN_MAX];
struct xbc_node *leaf;
const char *val;
int ret;
xbc_for_each_key_value(leaf, val) {
ret = xbc_node_compose_key(leaf, key, XBC_KEYLEN_MAX);
if (ret < 0) {
fprintf(stderr, "Failed to compose key %d\n", ret);
break;
}
printf("%s = ", key);
if (!val || val[0] == '\0') {
printf("\"\"\n");
continue;
}
xbc_show_value(xbc_node_get_child(leaf), false);
}
}
#define PAGE_SIZE 4096
static int load_xbc_fd(int fd, char **buf, int size)
{
int ret;
*buf = malloc(size + 1);
if (!*buf)
return -ENOMEM;
ret = read(fd, *buf, size);
if (ret < 0)
return -errno;
(*buf)[size] = '\0';
return ret;
}
/* Return the read size or -errno */
static int load_xbc_file(const char *path, char **buf)
{
struct stat stat;
int fd, ret;
fd = open(path, O_RDONLY);
if (fd < 0)
return -errno;
ret = fstat(fd, &stat);
if (ret < 0)
return -errno;
ret = load_xbc_fd(fd, buf, stat.st_size);
close(fd);
return ret;
}
static int pr_errno(const char *msg, int err)
{
pr_err("%s: %d\n", msg, err);
return err;
}
static int load_xbc_from_initrd(int fd, char **buf)
{
struct stat stat;
int ret;
uint32_t size = 0, csum = 0, rcsum;
char magic[BOOTCONFIG_MAGIC_LEN];
const char *msg;
ret = fstat(fd, &stat);
if (ret < 0)
return -errno;
if (stat.st_size < 8 + BOOTCONFIG_MAGIC_LEN)
return 0;
if (lseek(fd, -BOOTCONFIG_MAGIC_LEN, SEEK_END) < 0)
return pr_errno("Failed to lseek for magic", -errno);
if (read(fd, magic, BOOTCONFIG_MAGIC_LEN) < 0)
return pr_errno("Failed to read", -errno);
/* Check the bootconfig magic bytes */
if (memcmp(magic, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN) != 0)
return 0;
if (lseek(fd, -(8 + BOOTCONFIG_MAGIC_LEN), SEEK_END) < 0)
return pr_errno("Failed to lseek for size", -errno);
if (read(fd, &size, sizeof(uint32_t)) < 0)
return pr_errno("Failed to read size", -errno);
size = le32toh(size);
if (read(fd, &csum, sizeof(uint32_t)) < 0)
return pr_errno("Failed to read checksum", -errno);
csum = le32toh(csum);
/* Wrong size error */
if (stat.st_size < size + 8 + BOOTCONFIG_MAGIC_LEN) {
pr_err("bootconfig size is too big\n");
return -E2BIG;
}
if (lseek(fd, stat.st_size - (size + 8 + BOOTCONFIG_MAGIC_LEN),
SEEK_SET) < 0)
return pr_errno("Failed to lseek", -errno);
ret = load_xbc_fd(fd, buf, size);
if (ret < 0)
return ret;
/* Wrong Checksum */
rcsum = xbc_calc_checksum(*buf, size);
if (csum != rcsum) {
pr_err("checksum error: %d != %d\n", csum, rcsum);
return -EINVAL;
}
ret = xbc_init(*buf, size, &msg, NULL);
/* Wrong data */
if (ret < 0) {
pr_err("parse error: %s.\n", msg);
return ret;
}
return size;
}
static void show_xbc_error(const char *data, const char *msg, int pos)
{
int lin = 1, col, i;
if (pos < 0) {
pr_err("Error: %s.\n", msg);
return;
}
/* Note that pos starts from 0 but lin and col should start from 1. */
col = pos + 1;
for (i = 0; i < pos; i++) {
if (data[i] == '\n') {
lin++;
col = pos - i;
}
}
pr_err("Parse Error: %s at %d:%d\n", msg, lin, col);
}
static int init_xbc_with_error(char *buf, int len)
{
char *copy = strdup(buf);
const char *msg;
int ret, pos;
if (!copy)
return -ENOMEM;
ret = xbc_init(buf, len, &msg, &pos);
if (ret < 0)
show_xbc_error(copy, msg, pos);
free(copy);
return ret;
}
static int show_xbc(const char *path, bool list)
{
int ret, fd;
char *buf = NULL;
struct stat st;
ret = stat(path, &st);
if (ret < 0) {
ret = -errno;
pr_err("Failed to stat %s: %d\n", path, ret);
return ret;
}
fd = open(path, O_RDONLY);
if (fd < 0) {
ret = -errno;
pr_err("Failed to open initrd %s: %d\n", path, ret);
return ret;
}
ret = load_xbc_from_initrd(fd, &buf);
close(fd);
if (ret < 0) {
pr_err("Failed to load a boot config from initrd: %d\n", ret);
goto out;
}
/* Assume a bootconfig file if it is enough small */
if (ret == 0 && st.st_size <= XBC_DATA_MAX) {
ret = load_xbc_file(path, &buf);
if (ret < 0) {
pr_err("Failed to load a boot config: %d\n", ret);
goto out;
}
if (init_xbc_with_error(buf, ret) < 0)
goto out;
}
if (list)
xbc_show_list();
else
xbc_show_compact_tree();
ret = 0;
out:
free(buf);
return ret;
}
static int delete_xbc(const char *path)
{
struct stat stat;
int ret = 0, fd, size;
char *buf = NULL;
fd = open(path, O_RDWR);
if (fd < 0) {
ret = -errno;
pr_err("Failed to open initrd %s: %d\n", path, ret);
return ret;
}
size = load_xbc_from_initrd(fd, &buf);
if (size < 0) {
ret = size;
pr_err("Failed to load a boot config from initrd: %d\n", ret);
} else if (size > 0) {
ret = fstat(fd, &stat);
if (!ret)
ret = ftruncate(fd, stat.st_size
- size - 8 - BOOTCONFIG_MAGIC_LEN);
if (ret)
ret = -errno;
} /* Ignore if there is no boot config in initrd */
close(fd);
free(buf);
return ret;
}
static int apply_xbc(const char *path, const char *xbc_path)
{
char *buf, *data, *p;
size_t total_size;
struct stat stat;
const char *msg;
uint32_t size, csum;
int pos, pad;
int ret, fd;
ret = load_xbc_file(xbc_path, &buf);
if (ret < 0) {
pr_err("Failed to load %s : %d\n", xbc_path, ret);
return ret;
}
size = strlen(buf) + 1;
csum = xbc_calc_checksum(buf, size);
/* Backup the bootconfig data */
data = calloc(size + BOOTCONFIG_ALIGN +
sizeof(uint32_t) + sizeof(uint32_t) + BOOTCONFIG_MAGIC_LEN, 1);
if (!data)
return -ENOMEM;
memcpy(data, buf, size);
/* Check the data format */
ret = xbc_init(buf, size, &msg, &pos);
if (ret < 0) {
show_xbc_error(data, msg, pos);
free(data);
free(buf);
return ret;
}
printf("Apply %s to %s\n", xbc_path, path);
xbc_get_info(&ret, NULL);
printf("\tNumber of nodes: %d\n", ret);
printf("\tSize: %u bytes\n", (unsigned int)size);
printf("\tChecksum: %d\n", (unsigned int)csum);
/* TODO: Check the options by schema */
xbc_exit();
free(buf);
/* Remove old boot config if exists */
ret = delete_xbc(path);
if (ret < 0) {
pr_err("Failed to delete previous boot config: %d\n", ret);
free(data);
return ret;
}
/* Apply new one */
fd = open(path, O_RDWR | O_APPEND);
if (fd < 0) {
ret = -errno;
pr_err("Failed to open %s: %d\n", path, ret);
free(data);
return ret;
}
/* TODO: Ensure the @path is initramfs/initrd image */
if (fstat(fd, &stat) < 0) {
ret = -errno;
pr_err("Failed to get the size of %s\n", path);
goto out;
}
/* To align up the total size to BOOTCONFIG_ALIGN, get padding size */
total_size = stat.st_size + size + sizeof(uint32_t) * 2 + BOOTCONFIG_MAGIC_LEN;
pad = ((total_size + BOOTCONFIG_ALIGN - 1) & (~BOOTCONFIG_ALIGN_MASK)) - total_size;
size += pad;
/* Add a footer */
p = data + size;
*(uint32_t *)p = htole32(size);
p += sizeof(uint32_t);
*(uint32_t *)p = htole32(csum);
p += sizeof(uint32_t);
memcpy(p, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN);
p += BOOTCONFIG_MAGIC_LEN;
total_size = p - data;
ret = write(fd, data, total_size);
if (ret < total_size) {
if (ret < 0)
ret = -errno;
pr_err("Failed to apply a boot config: %d\n", ret);
if (ret >= 0)
goto out_rollback;
} else
ret = 0;
out:
close(fd);
free(data);
return ret;
out_rollback:
/* Map the partial write to -ENOSPC */
if (ret >= 0)
ret = -ENOSPC;
if (ftruncate(fd, stat.st_size) < 0) {
ret = -errno;
pr_err("Failed to rollback the write error: %d\n", ret);
pr_err("The initrd %s may be corrupted. Recommend to rebuild.\n", path);
}
goto out;
}
static int usage(void)
{
printf("Usage: bootconfig [OPTIONS] <INITRD>\n"
"Or bootconfig <CONFIG>\n"
" Apply, delete or show boot config to initrd.\n"
" Options:\n"
" -a <config>: Apply boot config to initrd\n"
" -d : Delete boot config file from initrd\n"
" -l : list boot config in initrd or file\n\n"
" If no option is given, show the bootconfig in the given file.\n");
return -1;
}
int main(int argc, char **argv)
{
char *path = NULL;
char *apply = NULL;
bool delete = false, list = false;
int opt;
while ((opt = getopt(argc, argv, "hda:l")) != -1) {
switch (opt) {
case 'd':
delete = true;
break;
case 'a':
apply = optarg;
break;
case 'l':
list = true;
break;
case 'h':
default:
return usage();
}
}
if ((apply && delete) || (delete && list) || (apply && list)) {
pr_err("Error: You can give one of -a, -d or -l at once.\n");
return usage();
}
if (optind >= argc) {
pr_err("Error: No initrd is specified.\n");
return usage();
}
path = argv[optind];
if (apply)
return apply_xbc(path, apply);
else if (delete)
return delete_xbc(path);
return show_xbc(path, list);
}
