Function writeSaveFiles

src/library/checkpoint/Checkpoint.cpp:1611–1758

Write a memory area into the savestate. Returns the size of the area in bytes */

/* Write a memory area into the savestate. Returns the size of the area in bytes */
static size_t writeSaveFiles(SaveStateSaving &state)
{
    size_t total_size = 0;
    
    for (auto it = SaveFileList::begin(); it != SaveFileList::end(); it++) {
        const std::unique_ptr<SaveFile>& savefile = *it;
        /* Don't map if file was closed and removed (TODO: handle this!) */
        if (savefile->fd == 0)
            continue;
            
        /* Also, skip if we are handling the savefile using our custom
         * stream (SaveFileStream), which maps its content in memory. So, it
         * is already saved through the memory dumping process. */
        if (savefile->fd >= FIRST_SAVEFILE_STREAM_FD)
            continue;
            
        Area area;
        area.flags = Area::AREA_SAVEFILE;
        area.fd = savefile->fd;
        strncpy(area.name, savefile->filename.c_str(), Area::FILENAMESIZE-1);
        
        /* Get current file length and map at least this amount of bytes */
        struct stat filestat;
        int rv = fstat(area.fd, &filestat);

        if (rv < 0)
            continue;
        
        area.size = filestat.st_size;
        
        if (area.size == 0) {
            LOG(LL_DEBUG, LCF_CHECKPOINT | LCF_FILEIO, "     Don't map empty/missing file %s with fd %d", savefile->filename.c_str(), savefile->fd);        
            continue;
        }
        
        area.addr = mmap(nullptr, area.size, PROT_READ, MAP_PRIVATE | MAP_FILE, savefile->fd, 0);
        
        if (area.addr == MAP_FAILED) {
            LOG(LL_DEBUG, LCF_CHECKPOINT | LCF_FILEIO, "     Cound not map file %s with fd %d and size %zu", savefile->filename.c_str(), savefile->fd, area.size);
            continue;
        }

        LOG(LL_DEBUG, LCF_CHECKPOINT | LCF_FILEIO, "Save savefile %s with fd %d and size %zu", savefile->filename.c_str(), savefile->fd, area.size);

        /* Map the original file */
        int orig_fd = -1;
        size_t orig_file_mapped_size = 0;
        void* orig_file_mapped_addr = MAP_FAILED;
        
        rv = stat(savefile->filename.c_str(), &filestat);

        if (rv < 0)
            LOG(LL_DEBUG, LCF_CHECKPOINT | LCF_FILEIO, "     No original savefile to use");
        else if (! S_ISREG(filestat.st_mode) || (filestat.st_size == 0))
            LOG(LL_DEBUG, LCF_CHECKPOINT | LCF_FILEIO, "    Original file is missing or not regular, skip it");
        else {
            orig_fd = open(savefile->filename.c_str(), O_RDONLY);