mirror of https://github.com/akuker/RASCSI.git
407 lines
12 KiB
C++
407 lines
12 KiB
C++
//---------------------------------------------------------------------------
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//
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// SCSI Target Emulator RaSCSI (*^..^*)
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// for Raspberry Pi
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//
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// Copyright (C) 2021 Uwe Seimet
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//
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//---------------------------------------------------------------------------
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#include <unistd.h>
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#include <sys/sendfile.h>
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#include "os.h"
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#include "log.h"
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#include "filepath.h"
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#include "spdlog/spdlog.h"
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#include "devices/file_support.h"
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#include "protobuf_util.h"
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#include "rascsi_image.h"
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#include <string>
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#include <filesystem>
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using namespace std;
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using namespace spdlog;
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using namespace rascsi_interface;
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using namespace protobuf_util;
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#define FPRT(fp, ...) fprintf(fp, __VA_ARGS__ )
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RascsiImage::RascsiImage()
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{
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// ~/images is the default folder for device image files, for the root user it is /home/pi/images
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int uid = getuid();
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const char *sudo_user = getenv("SUDO_UID");
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if (sudo_user) {
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uid = stoi(sudo_user);
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}
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const passwd *passwd = getpwuid(uid);
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if (uid && passwd) {
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default_image_folder = passwd->pw_dir;
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default_image_folder += "/images";
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}
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else {
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default_image_folder = "/home/pi/images";
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}
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depth = 1;
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}
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bool RascsiImage::CheckDepth(const string& filename)
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{
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return count(filename.begin(), filename.end(), '/') <= depth;
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}
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bool RascsiImage::CreateImageFolder(const CommandContext& context, const string& filename)
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{
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size_t filename_start = filename.rfind('/');
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if (filename_start != string::npos) {
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string folder = filename.substr(0, filename_start);
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// Checking for existence first prevents an error if the top-level folder is a softlink
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struct stat st;
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if (stat(folder.c_str(), &st)) {
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std::error_code error;
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filesystem::create_directories(folder, error);
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if (error) {
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ReturnStatus(context, false, "Can't create image folder '" + folder + "': " + strerror(errno));
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return false;
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}
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}
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}
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return true;
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}
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string RascsiImage::SetDefaultImageFolder(const string& f)
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{
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if (f.empty()) {
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return "Can't set default image folder: Missing folder name";
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}
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string folder = f;
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// If a relative path is specified the path is assumed to be relative to the user's home directory
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if (folder[0] != '/') {
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int uid = getuid();
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const char *sudo_user = getenv("SUDO_UID");
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if (sudo_user) {
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uid = stoi(sudo_user);
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}
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const passwd *passwd = getpwuid(uid);
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if (passwd) {
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folder = passwd->pw_dir;
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folder += "/";
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folder += f;
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}
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}
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else {
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if (folder.find("/home/") != 0) {
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return "Default image folder must be located in '/home/'";
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}
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}
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struct stat info;
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stat(folder.c_str(), &info);
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if (!S_ISDIR(info.st_mode) || access(folder.c_str(), F_OK) == -1) {
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return "Folder '" + f + "' does not exist or is not accessible";
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}
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default_image_folder = folder;
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LOGINFO("Default image folder set to '%s'", default_image_folder.c_str());
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return "";
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}
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bool RascsiImage::IsValidSrcFilename(const string& filename)
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{
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// Source file must exist and must be a regular file or a symlink
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struct stat st;
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return !stat(filename.c_str(), &st) && (S_ISREG(st.st_mode) || S_ISLNK(st.st_mode));
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}
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bool RascsiImage::IsValidDstFilename(const string& filename)
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{
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// Destination file must not yet exist
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struct stat st;
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return stat(filename.c_str(), &st);
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}
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bool RascsiImage::CreateImage(const CommandContext& context, const PbCommand& command)
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{
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string filename = GetParam(command, "file");
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if (filename.empty()) {
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return ReturnStatus(context, false, "Can't create image file: Missing image filename");
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}
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if (!CheckDepth(filename)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + filename + "'").c_str());
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}
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string full_filename = default_image_folder + "/" + filename;
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if (!IsValidDstFilename(full_filename)) {
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return ReturnStatus(context, false, "Can't create image file: '" + full_filename + "': File already exists");
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}
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const string size = GetParam(command, "size");
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if (size.empty()) {
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return ReturnStatus(context, false, "Can't create image file '" + full_filename + "': Missing image size");
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}
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off_t len;
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try {
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len = stoull(size);
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}
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catch(const invalid_argument& e) {
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return ReturnStatus(context, false, "Can't create image file '" + full_filename + "': Invalid file size " + size);
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}
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catch(const out_of_range& e) {
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return ReturnStatus(context, false, "Can't create image file '" + full_filename + "': Invalid file size " + size);
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}
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if (len < 512 || (len & 0x1ff)) {
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return ReturnStatus(context, false, "Invalid image file size " + to_string(len) + " (not a multiple of 512)");
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}
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if (!CreateImageFolder(context, full_filename)) {
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return false;
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}
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string permission = GetParam(command, "read_only");
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// Since rascsi is running as root ensure that others can access the file
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int permissions = !strcasecmp(permission.c_str(), "true") ?
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S_IRUSR | S_IRGRP | S_IROTH : S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
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int image_fd = open(full_filename.c_str(), O_CREAT|O_WRONLY, permissions);
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if (image_fd == -1) {
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return ReturnStatus(context, false, "Can't create image file '" + full_filename + "': " + string(strerror(errno)));
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}
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if (fallocate(image_fd, 0, 0, len)) {
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close(image_fd);
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unlink(full_filename.c_str());
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return ReturnStatus(context, false, "Can't allocate space for image file '" + full_filename + "': " + string(strerror(errno)));
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}
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close(image_fd);
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LOGINFO("%s", string("Created " + string(permissions & S_IWUSR ? "": "read-only ") + "image file '" + full_filename +
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"' with a size of " + to_string(len) + " bytes").c_str());
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return ReturnStatus(context);
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}
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bool RascsiImage::DeleteImage(const CommandContext& context, const PbCommand& command)
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{
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string filename = GetParam(command, "file");
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if (filename.empty()) {
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return ReturnStatus(context, false, "Missing image filename");
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}
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if (!CheckDepth(filename)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + filename + "'").c_str());
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}
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string full_filename = default_image_folder + "/" + filename;
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int id;
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int unit;
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Filepath filepath;
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filepath.SetPath(full_filename.c_str());
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if (FileSupport::GetIdsForReservedFile(filepath, id, unit)) {
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return ReturnStatus(context, false, "Can't delete image file '" + full_filename +
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"', it is currently being used by device ID " + to_string(id) + ", unit " + to_string(unit));
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}
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if (remove(full_filename.c_str())) {
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return ReturnStatus(context, false, "Can't delete image file '" + full_filename + "': " + string(strerror(errno)));
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}
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// Delete empty subfolders
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size_t last_slash = filename.rfind('/');
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while (last_slash != string::npos) {
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string folder = filename.substr(0, last_slash);
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string full_folder = default_image_folder + "/" + folder;
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std::error_code error;
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if (!filesystem::is_empty(full_folder, error) || error) {
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break;
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}
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if (remove(full_folder.c_str())) {
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return ReturnStatus(context, false, "Can't delete empty image folder '" + full_folder + "'");
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}
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last_slash = folder.rfind('/');
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}
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LOGINFO("Deleted image file '%s'", full_filename.c_str());
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return ReturnStatus(context);
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}
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bool RascsiImage::RenameImage(const CommandContext& context, const PbCommand& command)
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{
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string from = GetParam(command, "from");
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if (from.empty()) {
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return ReturnStatus(context, false, "Can't rename/move image file: Missing source filename");
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}
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if (!CheckDepth(from)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + from + "'").c_str());
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}
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from = default_image_folder + "/" + from;
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if (!IsValidSrcFilename(from)) {
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return ReturnStatus(context, false, "Can't rename/move image file: '" + from + "': Invalid name or type");
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}
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string to = GetParam(command, "to");
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if (to.empty()) {
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return ReturnStatus(context, false, "Can't rename/move image file '" + from + "': Missing destination filename");
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}
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if (!CheckDepth(to)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + to + "'").c_str());
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}
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to = default_image_folder + "/" + to;
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if (!IsValidDstFilename(to)) {
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return ReturnStatus(context, false, "Can't rename/move image file '" + from + "' to '" + to + "': File already exists");
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}
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if (!CreateImageFolder(context, to)) {
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return false;
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}
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if (rename(from.c_str(), to.c_str())) {
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return ReturnStatus(context, false, "Can't rename/move image file '" + from + "' to '" + to + "': " + string(strerror(errno)));
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}
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LOGINFO("Renamed/Moved image file '%s' to '%s'", from.c_str(), to.c_str());
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return ReturnStatus(context);
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}
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bool RascsiImage::CopyImage(const CommandContext& context, const PbCommand& command)
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{
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string from = GetParam(command, "from");
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if (from.empty()) {
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return ReturnStatus(context, false, "Can't copy image file: Missing source filename");
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}
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if (!CheckDepth(from)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + from + "'").c_str());
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}
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from = default_image_folder + "/" + from;
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if (!IsValidSrcFilename(from)) {
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return ReturnStatus(context, false, "Can't copy image file: '" + from + "': Invalid name or type");
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}
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string to = GetParam(command, "to");
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if (to.empty()) {
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return ReturnStatus(context, false, "Can't copy image file '" + from + "': Missing destination filename");
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}
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if (!CheckDepth(to)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + to + "'").c_str());
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}
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to = default_image_folder + "/" + to;
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if (!IsValidDstFilename(to)) {
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return ReturnStatus(context, false, "Can't copy image file '" + from + "' to '" + to + "': File already exists");
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}
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struct stat st;
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if (lstat(from.c_str(), &st)) {
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return ReturnStatus(context, false, "Can't access source image file '" + from + "': " + string(strerror(errno)));
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}
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if (!CreateImageFolder(context, to)) {
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return false;
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}
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// Symbolic links need a special handling
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if ((st.st_mode & S_IFMT) == S_IFLNK) {
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if (symlink(filesystem::read_symlink(from).c_str(), to.c_str())) {
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return ReturnStatus(context, false, "Can't copy symlink '" + from + "': " + string(strerror(errno)));
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}
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LOGINFO("Copied symlink '%s' to '%s'", from.c_str(), to.c_str());
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return ReturnStatus(context);
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}
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int fd_src = open(from.c_str(), O_RDONLY, 0);
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if (fd_src == -1) {
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return ReturnStatus(context, false, "Can't open source image file '" + from + "': " + string(strerror(errno)));
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}
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string permission = GetParam(command, "read_only");
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// Since rascsi is running as root ensure that others can access the file
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int permissions = !strcasecmp(permission.c_str(), "true") ?
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S_IRUSR | S_IRGRP | S_IROTH : S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
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int fd_dst = open(to.c_str(), O_WRONLY | O_CREAT, permissions);
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if (fd_dst == -1) {
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close(fd_src);
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return ReturnStatus(context, false, "Can't open destination image file '" + to + "': " + string(strerror(errno)));
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}
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if (sendfile(fd_dst, fd_src, 0, st.st_size) == -1) {
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close(fd_dst);
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close(fd_src);
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unlink(to.c_str());
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return ReturnStatus(context, false, "Can't copy image file '" + from + "' to '" + to + "': " + string(strerror(errno)));
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}
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close(fd_dst);
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close(fd_src);
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LOGINFO("Copied image file '%s' to '%s'", from.c_str(), to.c_str());
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return ReturnStatus(context);
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}
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bool RascsiImage::SetImagePermissions(const CommandContext& context, const PbCommand& command)
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{
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string filename = GetParam(command, "file");
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if (filename.empty()) {
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return ReturnStatus(context, false, "Missing image filename");
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}
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if (!CheckDepth(filename)) {
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return ReturnStatus(context, false, ("Invalid folder hierarchy depth '" + filename + "'").c_str());
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}
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filename = default_image_folder + "/" + filename;
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if (!IsValidSrcFilename(filename)) {
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return ReturnStatus(context, false, "Can't modify image file '" + filename + "': Invalid name or type");
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}
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bool protect = command.operation() == PROTECT_IMAGE;
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int permissions = protect ? S_IRUSR | S_IRGRP | S_IROTH : S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
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if (chmod(filename.c_str(), permissions) == -1) {
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return ReturnStatus(context, false, "Can't " + string(protect ? "protect" : "unprotect") + " image file '" + filename + "': " +
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strerror(errno));
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}
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if (protect) {
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LOGINFO("Protected image file '%s'", filename.c_str());
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}
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else {
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LOGINFO("Unprotected image file '%s'", filename.c_str());
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}
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return ReturnStatus(context);
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}
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