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Diffstat (limited to 'tools/ota/make-update-script.c')
| -rw-r--r-- | tools/ota/make-update-script.c | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/tools/ota/make-update-script.c b/tools/ota/make-update-script.c new file mode 100644 index 0000000..0fb7ed0 --- /dev/null +++ b/tools/ota/make-update-script.c @@ -0,0 +1,228 @@ +/* + * Copyright (C) 2008 The Android Open Source Project + * + * Licensed 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 "private/android_filesystem_config.h" + +#include <dirent.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <sys/types.h> +#include <unistd.h> + +/* + * Recursively walk the directory tree at <sysdir>/<subdir>, writing + * script commands to set permissions and create symlinks. + * Assume the contents already have the specified default permissions, + * so only output commands if they need to be changed from the defaults. + * + * Note that permissions are set by fs_config(), which uses a lookup table of + * Android permissions. They are not drawn from the build host filesystem. + */ +static void walk_files( + const char *sysdir, const char *subdir, + unsigned default_uid, unsigned default_gid, + unsigned default_dir_mode, unsigned default_file_mode) { + const char *sep = strcmp(subdir, "") ? "/" : ""; + + char fn[PATH_MAX]; + unsigned dir_uid = 0, dir_gid = 0, dir_mode = 0; + snprintf(fn, PATH_MAX, "system%s%s", sep, subdir); + fs_config(fn, 1, &dir_uid, &dir_gid, &dir_mode); + + snprintf(fn, PATH_MAX, "%s%s%s", sysdir, sep, subdir); + DIR *dir = opendir(fn); + if (dir == NULL) { + perror(fn); + exit(1); + } + + /* + * We can use "set_perm" and "set_perm_recursive" to set file permissions + * (owner, group, and file mode) for individual files and entire subtrees. + * We want to use set_perm_recursive efficiently to avoid setting the + * permissions of every single file in the system image individually. + * + * What we do is recursively set our entire subtree to the permissions + * used by the first file we encounter, and then use "set_perm" to adjust + * the permissions of subsequent files which don't match the first one. + * This is bad if the first file is an outlier, but it generally works. + * Subdirectories can do the same thing recursively if they're different. + */ + + int is_first = 1; + const struct dirent *e; + while ((e = readdir(dir))) { + // Skip over "." and ".." entries + if (!strcmp(e->d_name, ".") || !strcmp(e->d_name, "..")) continue; + + if (e->d_type == DT_LNK) { // Symlink + + // Symlinks don't really have permissions, so this is orthogonal. + snprintf(fn, PATH_MAX, "%s/%s%s%s", sysdir, subdir, sep, e->d_name); + int len = readlink(fn, fn, PATH_MAX - 1); + if (len <= 0) { + perror(fn); + exit(1); + } + fn[len] = '\0'; + printf("symlink %s SYSTEM:%s%s%s\n", fn, subdir, sep, e->d_name); + + } else if (e->d_type == DT_DIR) { // Subdirectory + + // Use the parent directory as the model for default permissions. + // We haven't seen a file, so just make up some file defaults. + if (is_first && ( + dir_mode != default_dir_mode || + dir_uid != default_uid || dir_gid != default_gid)) { + default_uid = dir_uid; + default_gid = dir_gid; + default_dir_mode = dir_mode; + default_file_mode = dir_mode & default_file_mode & 0666; + printf("set_perm_recursive %d %d 0%o 0%o SYSTEM:%s\n", + default_uid, default_gid, + default_dir_mode, default_file_mode, + subdir); + } + + is_first = 0; + + // Recursively handle the subdirectory. + // Note, the recursive call handles the directory's own permissions. + snprintf(fn, PATH_MAX, "%s%s%s", subdir, sep, e->d_name); + walk_files(sysdir, fn, + default_uid, default_gid, + default_dir_mode, default_file_mode); + + } else { // Ordinary file + + // Get the file's desired permissions. + unsigned file_uid = 0, file_gid = 0, file_mode = 0; + snprintf(fn, PATH_MAX, "system/%s%s%s", subdir, sep, e->d_name); + fs_config(fn, 0, &file_uid, &file_gid, &file_mode); + + // If this is the first file, its mode gets to become the default. + if (is_first && ( + dir_mode != default_dir_mode || + file_mode != default_file_mode || + dir_uid != default_uid || file_uid != default_uid || + dir_gid != default_gid || file_gid != default_gid)) { + default_uid = dir_uid; + default_gid = dir_gid; + default_dir_mode = dir_mode; + default_file_mode = file_mode; + printf("set_perm_recursive %d %d 0%o 0%o SYSTEM:%s\n", + default_uid, default_gid, + default_dir_mode, default_file_mode, + subdir); + } + + is_first = 0; + + // Otherwise, override this file if it doesn't match the defaults. + if (file_mode != default_file_mode || + file_uid != default_uid || file_gid != default_gid) { + printf("set_perm %d %d 0%o SYSTEM:%s%s%s\n", + file_uid, file_gid, file_mode, + subdir, sep, e->d_name); + } + + } + } + + // Set the directory's permissions directly, if they never got set. + if (dir_mode != default_dir_mode || + dir_uid != default_uid || dir_gid != default_gid) { + printf("set_perm %d %d 0%o SYSTEM:%s\n", + dir_uid, dir_gid, dir_mode, subdir); + } + + closedir(dir); +} + +/* + * Generate the update script (in "Amend", see commands/recovery/commands.c) + * for the complete-reinstall OTA update packages the build system makes. + * + * The generated script makes a variety of sanity checks about the device, + * erases and reinstalls system files, and sets file permissions appropriately. + */ +int main(int argc, char *argv[]) { + if (argc != 3) { + fprintf(stderr, "usage: %s systemdir android-info.txt >update-script\n", + argv[0]); + return 2; + } + + // ensure basic recovery script language compatibility + printf("assert compatible_with(\"0.2\") == \"true\"\n"); + + // if known, make sure the device name is correct + const char *device = getenv("TARGET_PRODUCT"); + if (device != NULL) { + printf("assert getprop(\"ro.product.device\") == \"%s\" || " + "getprop(\"ro.build.product\") == \"%s\"\n", device, device); + } + + // scan android-info.txt to enforce compatibility with the target system + FILE *fp = fopen(argv[2], "r"); + if (fp == NULL) { + perror(argv[2]); + return 1; + } + + // The lines we're looking for look like: + // version-bootloader=x.yy.zzzz + // or: + // require version-bootloader=x.yy.zzzz + char line[256]; + while (fgets(line, sizeof(line), fp)) { + const char *name = strtok(line, "="), *value = strtok(NULL, "\n"); + if (value != NULL && + (!strcmp(name, "version-bootloader") || + !strcmp(name, "require version-bootloader"))) { + printf("assert getprop(\"ro.bootloader\") == \"%s\"\n", value); + } + // We also used to check version-baseband, but we update radio.img + // ourselves, so there's no need. + } + + // erase the boot sector first, so if the update gets interrupted, + // the system will reboot into the recovery partition and start over. + printf("format BOOT:\n"); + + // write the radio image (actually just loads it into RAM for now) + printf("show_progress 0.1 0\n"); + printf("write_radio_image PACKAGE:radio.img\n"); + + // erase and reinstall the system image + printf("show_progress 0.5 0\n"); + printf("format SYSTEM:\n"); + printf("copy_dir PACKAGE:system SYSTEM:\n"); + + // walk the files in the system image, set their permissions, etc. + // use -1 for default values to force permissions to be set explicitly. + walk_files(argv[1], "", -1, -1, -1, -1); + + // as the last step, write the boot sector. + printf("show_progress 0.2 0\n"); + printf("write_raw_image PACKAGE:boot.img BOOT:\n"); + + // after the end of the script, the radio will be written to cache + // leave some space in the progress bar for this operation + printf("show_progress 0.2 10\n"); + return 0; +} |