X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=scandir.cc;h=0dfdbdba58518dd7e7f91ec9cd375a8c86110731;hb=c7c7041c1b79ffb27647d74a6a345dfcfbf9f190;hp=7e02f2708becbb1041a8dbb85ff306530b0a239b;hpb=ce15b42a3385cb50dab7f8a58bf310ba5a57958e;p=cumulus.git diff --git a/scandir.cc b/scandir.cc index 7e02f27..0dfdbdb 100644 --- a/scandir.cc +++ b/scandir.cc @@ -4,63 +4,340 @@ #include #include #include +#include #include +#include +#include #include #include #include +#include #include +#include +#include +#include +#include +#include +#include +#include "format.h" +#include "localdb.h" +#include "store.h" +#include "sha1.h" + +using std::list; using std::string; +using std::vector; +using std::ostream; + +static TarSegmentStore *tss = NULL; + +/* Buffer for holding a single block of data read from a file. */ +static const size_t LBS_BLOCK_SIZE = 1024 * 1024; +static char *block_buf; + +static const size_t LBS_METADATA_BLOCK_SIZE = 65536; + +/* Local database, which tracks objects written in this and previous + * invocations to help in creating incremental snapshots. */ +LocalDb *db; + +/* Contents of the root object. This will contain a set of indirect links to + * the metadata objects. */ +std::ostringstream metadata_root; + +/* Buffer for building up metadata. */ +std::ostringstream metadata; + +/* Keep track of all segments which are needed to reconstruct the snapshot. */ +std::set segment_list; void scandir(const string& path); +/* Ensure contents of metadata are flushed to an object. */ +void metadata_flush() +{ + string m = metadata.str(); + if (m.size() == 0) + return; + + /* Write current metadata information to a new object. */ + LbsObject *meta = new LbsObject; + meta->set_group("root"); + meta->set_data(m.data(), m.size()); + meta->write(tss); + meta->checksum(); + + /* Write a reference to this block in the root. */ + ObjectReference ref = meta->get_ref(); + metadata_root << "@" << ref.to_string() << "\n"; + segment_list.insert(ref.get_segment()); + + delete meta; + + metadata.str(""); +} + +/* Read data from a file descriptor and return the amount of data read. A + * short read (less than the requested size) will only occur if end-of-file is + * hit. */ +size_t file_read(int fd, char *buf, size_t maxlen) +{ + size_t bytes_read = 0; + + while (true) { + ssize_t res = read(fd, buf, maxlen); + if (res < 0) { + if (errno == EINTR) + continue; + throw IOException("file_read: error reading"); + } else if (res == 0) { + break; + } else { + bytes_read += res; + buf += res; + maxlen -= res; + } + } + + return bytes_read; +} + +/* Read the contents of a file (specified by an open file descriptor) and copy + * the data to the store. Returns the size of the file (number of bytes + * dumped), or -1 on error. */ +int64_t dumpfile(int fd, dictionary &file_info) +{ + struct stat stat_buf; + fstat(fd, &stat_buf); + int64_t size = 0; + list object_list; + + if ((stat_buf.st_mode & S_IFMT) != S_IFREG) { + fprintf(stderr, "file is no longer a regular file!\n"); + return -1; + } + + /* The index data consists of a sequence of pointers to the data blocks + * that actually comprise the file data. This level of indirection is used + * so that the same data block can be used in multiple files, or multiple + * versions of the same file. */ + SHA1Checksum hash; + while (true) { + size_t bytes = file_read(fd, block_buf, LBS_BLOCK_SIZE); + if (bytes == 0) + break; + + hash.process(block_buf, bytes); + + // Either find a copy of this block in an already-existing segment, or + // index it so it can be re-used in the future + SHA1Checksum block_hash; + block_hash.process(block_buf, bytes); + string block_csum = block_hash.checksum_str(); + ObjectReference ref = db->FindObject(block_csum, bytes); + + // Store a copy of the object if one does not yet exist + if (ref.get_segment().size() == 0) { + LbsObject *o = new LbsObject; + o->set_group("data"); + o->set_data(block_buf, bytes); + o->write(tss); + ref = o->get_ref(); + db->StoreObject(ref, block_csum, bytes); + delete o; + } + object_list.push_back(ref.to_string()); + segment_list.insert(ref.get_segment()); + size += bytes; + } + + file_info["checksum"] = hash.checksum_str(); + + /* For files that only need to be broken apart into a few objects, store + * the list of objects directly. For larger files, store the data + * out-of-line and provide a pointer to the indrect object. */ + if (object_list.size() < 8) { + string blocklist = ""; + for (list::iterator i = object_list.begin(); + i != object_list.end(); ++i) { + if (i != object_list.begin()) + blocklist += " "; + blocklist += *i; + } + file_info["data"] = blocklist; + } else { + string blocklist = ""; + for (list::iterator i = object_list.begin(); + i != object_list.end(); ++i) { + blocklist += *i + "\n"; + } + + LbsObject *i = new LbsObject; + i->set_group("indirect"); + i->set_data(blocklist.data(), blocklist.size()); + i->write(tss); + file_info["data"] = "@" + i->get_name(); + segment_list.insert(i->get_ref().get_segment()); + delete i; + } + + return size; +} + void scanfile(const string& path) { + int fd; + long flags; struct stat stat_buf; + char *buf; + ssize_t len; + int64_t file_size; + list refs; + + // Set to true if the item is a directory and we should recursively scan + bool recurse = false; + + dictionary file_info; + lstat(path.c_str(), &stat_buf); - printf("%s:\n", path.c_str()); - printf(" ino=%Ld, perm=%04o, uid=%d, gid=%d, nlink=%d, blksize=%d, size=%Ld\n", - (int64_t)stat_buf.st_ino, stat_buf.st_mode & 07777, - stat_buf.st_uid, stat_buf.st_gid, stat_buf.st_nlink, - (int)stat_buf.st_blksize, (int64_t)stat_buf.st_size); + printf("%s\n", path.c_str()); + + metadata << "name: " << uri_encode(path) << "\n"; + + file_info["mode"] = encode_int(stat_buf.st_mode & 07777); + file_info["mtime"] = encode_int(stat_buf.st_mtime); + file_info["user"] = encode_int(stat_buf.st_uid); + file_info["group"] = encode_int(stat_buf.st_gid); + + struct passwd *pwd = getpwuid(stat_buf.st_uid); + if (pwd != NULL) { + file_info["user"] += " (" + uri_encode(pwd->pw_name) + ")"; + } + + struct group *grp = getgrgid(stat_buf.st_gid); + if (pwd != NULL) { + file_info["group"] += " (" + uri_encode(grp->gr_name) + ")"; + } + + char inode_type; switch (stat_buf.st_mode & S_IFMT) { case S_IFIFO: + inode_type = 'p'; + break; case S_IFSOCK: + inode_type = 's'; + break; case S_IFCHR: + inode_type = 'c'; + break; case S_IFBLK: + inode_type = 'b'; + break; case S_IFLNK: - printf(" special file\n"); + inode_type = 'l'; + + /* Use the reported file size to allocate a buffer large enough to read + * the symlink. Allocate slightly more space, so that we ask for more + * bytes than we expect and so check for truncation. */ + buf = new char[stat_buf.st_size + 2]; + len = readlink(path.c_str(), buf, stat_buf.st_size + 1); + if (len < 0) { + fprintf(stderr, "error reading symlink: %m\n"); + } else if (len <= stat_buf.st_size) { + buf[len] = '\0'; + file_info["contents"] = uri_encode(buf); + } else if (len > stat_buf.st_size) { + fprintf(stderr, "error reading symlink: name truncated\n"); + } + + delete[] buf; break; case S_IFREG: - printf(" regular file\n"); + inode_type = '-'; + + /* Be paranoid when opening the file. We have no guarantee that the + * file was not replaced between the stat() call above and the open() + * call below, so we might not even be opening a regular file. That + * the file descriptor refers to a regular file is checked in + * dumpfile(). But we also supply flags to open to to guard against + * various conditions before we can perform that verification: + * - O_NOFOLLOW: in the event the file was replaced by a symlink + * - O_NONBLOCK: prevents open() from blocking if the file was + * replaced by a fifo + * We also add in O_NOATIME, since this may reduce disk writes (for + * inode updates). */ + fd = open(path.c_str(), O_RDONLY|O_NOATIME|O_NOFOLLOW|O_NONBLOCK); + + /* Drop the use of the O_NONBLOCK flag; we only wanted that for file + * open. */ + flags = fcntl(fd, F_GETFL); + fcntl(fd, F_SETFL, flags & ~O_NONBLOCK); + + file_size = dumpfile(fd, file_info); + file_info["size"] = encode_int(file_size); + close(fd); + + if (file_size < 0) + return; // error occurred; do not dump file + + if (file_size != stat_buf.st_size) { + fprintf(stderr, "Warning: Size of %s changed during reading\n", + path.c_str()); + } + break; case S_IFDIR: - printf(" directory\n"); - scandir(path); + inode_type = 'd'; + recurse = true; break; + + default: + fprintf(stderr, "Unknown inode type: mode=%x\n", stat_buf.st_mode); + return; } + + file_info["type"] = string(1, inode_type); + + dict_output(metadata, file_info); + metadata << "\n"; + + // Break apart metadata listing if it becomes too large. + if (metadata.str().size() > LBS_METADATA_BLOCK_SIZE) + metadata_flush(); + + // If we hit a directory, now that we've written the directory itself, + // recursively scan the directory. + if (recurse) + scandir(path); } void scandir(const string& path) { - printf("Scan directory: %s\n", path.c_str()); - DIR *dir = opendir(path.c_str()); if (dir == NULL) { - printf("Error: %m\n"); + fprintf(stderr, "Error: %m\n"); return; } struct dirent *ent; + vector contents; while ((ent = readdir(dir)) != NULL) { string filename(ent->d_name); if (filename == "." || filename == "..") continue; - printf(" d_name = '%s'\n", filename.c_str()); + contents.push_back(filename); + } + + sort(contents.begin(), contents.end()); + + for (vector::iterator i = contents.begin(); + i != contents.end(); ++i) { + const string& filename = *i; scanfile(path + "/" + filename); } @@ -69,7 +346,63 @@ void scandir(const string& path) int main(int argc, char *argv[]) { - scandir("."); + block_buf = new char[LBS_BLOCK_SIZE]; + + string backup_dest = "."; + + if (argc > 1) + backup_dest = argv[1]; + + tss = new TarSegmentStore(backup_dest); + + string database_path = backup_dest + "/localdb.sqlite"; + db = new LocalDb; + db->Open(database_path.c_str()); + + /* Write a backup descriptor file, which says which segments are needed and + * where to start to restore this snapshot. The filename is based on the + * current time. */ + time_t now; + struct tm time_buf; + char desc_buf[256]; + time(&now); + localtime_r(&now, &time_buf); + strftime(desc_buf, sizeof(desc_buf), "%Y%m%dT%H%M%S", &time_buf); + string desc_filename = backup_dest + "/" + desc_buf + ".lbs"; + std::ofstream descriptor(desc_filename.c_str()); + + try { + scanfile("."); + } catch (IOException e) { + fprintf(stderr, "IOException: %s\n", e.getError().c_str()); + } + + metadata_flush(); + const string md = metadata_root.str(); + + LbsObject *root = new LbsObject; + root->set_group("root"); + root->set_data(md.data(), md.size()); + root->write(tss); + root->checksum(); + + segment_list.insert(root->get_ref().get_segment()); + descriptor << "Root: " << root->get_ref().to_string() << "\n"; + strftime(desc_buf, sizeof(desc_buf), "%Y-%m-%d %H:%M:%S %z", &time_buf); + descriptor << "Date: " << desc_buf << "\n"; + + delete root; + + descriptor << "Segments:\n"; + for (std::set::iterator i = segment_list.begin(); + i != segment_list.end(); ++i) { + descriptor << " " << *i << "\n"; + } + + db->Close(); + + tss->sync(); + delete tss; return 0; }