platform_system_core/fastboot/fs.cpp

#include "fs.h"

#include "fastboot.h"
#include "make_f2fs.h"

#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#ifndef WIN32
#include <sys/wait.h>
#endif
#include <unistd.h>
#include <vector>

#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/unique_fd.h>
#include <ext4_utils/make_ext4fs.h>
#include <sparse/sparse.h>

using android::base::StringPrintf;
using android::base::unique_fd;

#ifdef WIN32
static int generate_ext4_image(const char* fileName, long long partSize, const std::string& initial_dir,
                                       unsigned eraseBlkSize, unsigned logicalBlkSize)
{
    unique_fd fd(open(fileName, O_CREAT | O_RDWR | O_TRUNC, S_IRUSR | S_IWUSR));
    if (fd == -1) {
        fprintf(stderr, "Unable to open output file for EXT4 filesystem: %s\n", strerror(errno));
        return -1;
    }
    if (initial_dir.empty()) {
        make_ext4fs_sparse_fd_align(fd, partSize, NULL, NULL, eraseBlkSize, logicalBlkSize);
    } else {
        make_ext4fs_sparse_fd_directory_align(fd, partSize, NULL, NULL, initial_dir.c_str(),
                                              eraseBlkSize, logicalBlkSize);
    }
    return 0;
}
#else
static int exec_e2fs_cmd(const char* path, char* const argv[]) {
    int status;
    pid_t child;
    if ((child = fork()) == 0) {
        setenv("MKE2FS_CONFIG", "", 1);
        execvp(path, argv);
        _exit(EXIT_FAILURE);
    }
    if (child < 0) {
        fprintf(stderr, "%s failed with fork %s\n", path, strerror(errno));
        return -1;
    }
    if (TEMP_FAILURE_RETRY(waitpid(child, &status, 0)) == -1) {
        fprintf(stderr, "%s failed with waitpid %s\n", path, strerror(errno));
        return -1;
    }
    int ret = -1;
    if (WIFEXITED(status)) {
        ret = WEXITSTATUS(status);
        if (ret != 0) {
            fprintf(stderr, "%s failed with status %d\n", path, ret);
        }
    }
    return ret;
}

static int generate_ext4_image(const char* fileName, long long partSize,
                               const std::string& initial_dir, unsigned eraseBlkSize,
                               unsigned logicalBlkSize) {
    static constexpr int block_size = 4096;
    const std::string exec_dir = android::base::GetExecutableDirectory();

    const std::string mke2fs_path = exec_dir + "/mke2fs";
    std::vector<const char*> mke2fs_args = {mke2fs_path.c_str(), "-t", "ext4", "-b"};

    std::string block_size_str = std::to_string(block_size);
    mke2fs_args.push_back(block_size_str.c_str());

    std::string ext_attr = "android_sparse";
    if (eraseBlkSize != 0 && logicalBlkSize != 0) {
        int raid_stride = logicalBlkSize / block_size;
        int raid_stripe_width = eraseBlkSize / block_size;
        // stride should be the max of 8kb and logical block size
        if (logicalBlkSize != 0 && logicalBlkSize < 8192) raid_stride = 8192 / block_size;
        ext_attr += StringPrintf(",stride=%d,stripe-width=%d", raid_stride, raid_stripe_width);
    }
    mke2fs_args.push_back("-E");
    mke2fs_args.push_back(ext_attr.c_str());
    mke2fs_args.push_back("-O");
    mke2fs_args.push_back("uninit_bg");
    mke2fs_args.push_back(fileName);

    std::string size_str = std::to_string(partSize / block_size);
    mke2fs_args.push_back(size_str.c_str());
    mke2fs_args.push_back(nullptr);

    int ret = exec_e2fs_cmd(mke2fs_args[0], const_cast<char**>(mke2fs_args.data()));
    if (ret != 0) {
        fprintf(stderr, "mke2fs failed: %d\n", ret);
        return -1;
    }

    if (initial_dir.empty()) {
        return 0;
    }

    const std::string e2fsdroid_path = exec_dir + "/e2fsdroid";
    std::vector<const char*> e2fsdroid_args = {e2fsdroid_path.c_str(), "-f", initial_dir.c_str(),
                                               fileName, nullptr};

    ret = exec_e2fs_cmd(e2fsdroid_args[0], const_cast<char**>(e2fsdroid_args.data()));
    if (ret != 0) {
        fprintf(stderr, "e2fsdroid failed: %d\n", ret);
        return -1;
    }

    return 0;
}
#endif

#ifdef USE_F2FS
static int generate_f2fs_image(const char* fileName, long long partSize, const std::string& initial_dir,
                               unsigned /* unused */, unsigned /* unused */)
{
    if (!initial_dir.empty()) {
        fprintf(stderr, "Unable to set initial directory on F2FS filesystem: %s\n", strerror(errno));
        return -1;
    }
    unique_fd fd(open(fileName, O_CREAT | O_RDWR | O_TRUNC, S_IRUSR | S_IWUSR));
    if (fd == -1) {
        fprintf(stderr, "Unable to open output file for F2FS filesystem: %s\n", strerror(errno));
        return -1;
    }
    return make_f2fs_sparse_fd(fd, partSize, NULL, NULL);
}
#endif

static const struct fs_generator {
    const char* fs_type;  //must match what fastboot reports for partition type

    //returns 0 or error value
    int (*generate)(const char* fileName, long long partSize, const std::string& initial_dir,
                    unsigned eraseBlkSize, unsigned logicalBlkSize);

} generators[] = {
    { "ext4", generate_ext4_image},
#ifdef USE_F2FS
    { "f2fs", generate_f2fs_image},
#endif
};

const struct fs_generator* fs_get_generator(const std::string& fs_type) {
    for (size_t i = 0; i < sizeof(generators) / sizeof(*generators); i++) {
        if (fs_type == generators[i].fs_type) {
            return generators + i;
        }
    }
    return nullptr;
}

int fs_generator_generate(const struct fs_generator* gen, const char* fileName, long long partSize,
    const std::string& initial_dir, unsigned eraseBlkSize, unsigned logicalBlkSize)
{
    return gen->generate(fileName, partSize, initial_dir, eraseBlkSize, logicalBlkSize);
}