X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=scandir.cc;h=f5ab2b6011274adc2e621f220107a6dfa996dee0;hb=87c6a5ed4ec515c2e154f98529c1d2f077d2a7e4;hp=702fce2778879d35c35471606379274715c172d0;hpb=6fc3c86d0c9fc87ae993577c9954dbdca725a64d;p=cumulus.git diff --git a/scandir.cc b/scandir.cc index 702fce2..f5ab2b6 100644 --- a/scandir.cc +++ b/scandir.cc @@ -1,38 +1,63 @@ /* Recursively descend the filesystem and visit each file. */ -#include -#include -#include #include #include #include -#include +#include +#include +#include +#include +#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" +#include "statcache.h" +#include "util.h" using std::list; using std::string; using std::vector; using std::ostream; +/* Version information. This will be filled in by the Makefile. */ +#ifndef LBS_VERSION +#define LBS_VERSION Unknown +#endif +#define LBS_STRINGIFY(s) LBS_STRINGIFY2(s) +#define LBS_STRINGIFY2(s) #s +static const char lbs_version[] = LBS_STRINGIFY(LBS_VERSION); + static TarSegmentStore *tss = NULL; /* Buffer for holding a single block of data read from a file. */ -static const int LBS_BLOCK_SIZE = 1024 * 1024; +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; + +/* Stat cache, which stored data locally to speed the backup process by quickly + * skipping files which have not changed. */ +StatCache *statcache; + /* Contents of the root object. This will contain a set of indirect links to * the metadata objects. */ std::ostringstream metadata_root; @@ -43,7 +68,14 @@ std::ostringstream metadata; /* Keep track of all segments which are needed to reconstruct the snapshot. */ std::set segment_list; -void scandir(const string& path); +/* Selection of files to include/exclude in the snapshot. */ +std::list includes; // Paths in which files should be saved +std::list excludes; // Paths which will not be saved +std::list searches; // Directories we don't want to save, but + // do want to descend searching for data + // in included paths + +bool relative_paths = true; /* Ensure contents of metadata are flushed to an object. */ void metadata_flush() @@ -54,7 +86,7 @@ void metadata_flush() /* Write current metadata information to a new object. */ LbsObject *meta = new LbsObject; - meta->set_group("root"); + meta->set_group("metadata"); meta->set_data(m.data(), m.size()); meta->write(tss); meta->checksum(); @@ -72,7 +104,7 @@ void metadata_flush() /* 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) +ssize_t file_read(int fd, char *buf, size_t maxlen) { size_t bytes_read = 0; @@ -81,7 +113,8 @@ size_t file_read(int fd, char *buf, size_t maxlen) if (res < 0) { if (errno == EINTR) continue; - throw IOException("file_read: error reading"); + fprintf(stderr, "error reading file: %m\n"); + return -1; } else if (res == 0) { break; } else { @@ -95,44 +128,111 @@ size_t file_read(int fd, char *buf, size_t maxlen) } /* Read the contents of a file (specified by an open file descriptor) and copy - * the data to the store. */ -void dumpfile(int fd, dictionary &file_info) + * 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, const string &path, + struct stat& stat_buf) { - struct stat stat_buf; - fstat(fd, &stat_buf); int64_t size = 0; list object_list; - if ((stat_buf.st_mode & S_IFMT) != S_IFREG) { - printf("file is no longer a regular file!\n"); - return; - } - - /* 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; + /* Look up this file in the old stat cache, if we can. If the stat + * information indicates that the file has not changed, do not bother + * re-reading the entire contents. */ + bool cached = false; + + if (statcache->Find(path, &stat_buf)) { + cached = true; + const list &blocks = statcache->get_blocks(); + + /* If any of the blocks in the object have been expired, then we should + * fall back to fully reading in the file. */ + for (list::const_iterator i = blocks.begin(); + i != blocks.end(); ++i) { + const ObjectReference &ref = *i; + if (!db->IsAvailable(ref)) { + cached = false; + break; + } + } - hash.process(block_buf, bytes); + /* If everything looks okay, use the cached information */ + if (cached) { + file_info["checksum"] = statcache->get_checksum(); + for (list::const_iterator i = blocks.begin(); + i != blocks.end(); ++i) { + const ObjectReference &ref = *i; + object_list.push_back(ref.to_string()); + segment_list.insert(ref.get_segment()); + db->UseObject(ref); + } + size = stat_buf.st_size; + } + } - // tarstore processing - LbsObject *o = new LbsObject; - o->set_group("data"); - o->set_data(block_buf, bytes); - o->write(tss); - object_list.push_back(o->get_name()); - segment_list.insert(o->get_ref().get_segment()); - delete o; + /* If the file is new or changed, we must read in the contents a block at a + * time. */ + if (!cached) { + printf(" [new]\n"); + + SHA1Checksum hash; + while (true) { + ssize_t bytes = file_read(fd, block_buf, LBS_BLOCK_SIZE); + if (bytes == 0) + break; + if (bytes < 0) { + fprintf(stderr, "Backup contents for %s may be incorrect\n", + path.c_str()); + 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 + double block_age = 0.0; + 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; + + /* We might still have seen this checksum before, if the object + * was stored at some time in the past, but we have decided to + * clean the segment the object was originally stored in + * (FindObject will not return such objects). When rewriting + * the object contents, put it in a separate group, so that old + * objects get grouped together. The hope is that these old + * objects will continue to be used in the future, and we + * obtain segments which will continue to be well-utilized. + * Additionally, keep track of the age of the data by looking + * up the age of the block which was expired and using that + * instead of the current time. */ + if (db->IsOldObject(block_csum, bytes, &block_age)) + o->set_group("compacted"); + else + o->set_group("data"); + + o->set_data(block_buf, bytes); + o->write(tss); + ref = o->get_ref(); + db->StoreObject(ref, block_csum, bytes, block_age); + delete o; + } + + object_list.push_back(ref.to_string()); + segment_list.insert(ref.get_segment()); + db->UseObject(ref); + size += bytes; + } - size += bytes; + file_info["checksum"] = hash.checksum_str(); } - file_info["checksum"] = hash.checksum_str(); + statcache->Save(path, &stat_buf, file_info["checksum"], object_list); /* 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 @@ -154,42 +254,47 @@ void dumpfile(int fd, dictionary &file_info) } LbsObject *i = new LbsObject; - i->set_group("indirect"); + i->set_group("metadata"); 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) +/* Dump a specified filesystem object (file, directory, etc.) based on its + * inode information. If the object is a regular file, an open filehandle is + * provided. */ +void dump_inode(const string& path, // Path within snapshot + const string& fullpath, // Path to object in filesystem + struct stat& stat_buf, // Results of stat() call + int fd) // Open filehandle if regular file { - int fd; - long flags; - struct stat stat_buf; char *buf; - ssize_t len; - 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); + int64_t file_size; + ssize_t len; printf("%s\n", path.c_str()); - metadata << "name: " << uri_encode(path) << "\n"; - - file_info["mode"] = encode_int(stat_buf.st_mode & 07777); - file_info["atime"] = encode_int(stat_buf.st_atime); - file_info["ctime"] = encode_int(stat_buf.st_ctime); + file_info["mode"] = encode_int(stat_buf.st_mode & 07777, 8); 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) { @@ -199,11 +304,11 @@ void scanfile(const string& path) case S_IFSOCK: inode_type = 's'; break; - case S_IFCHR: - inode_type = 'c'; - break; case S_IFBLK: - inode_type = 'b'; + case S_IFCHR: + inode_type = ((stat_buf.st_mode & S_IFMT) == S_IFBLK) ? 'b' : 'c'; + file_info["device"] = encode_int(major(stat_buf.st_rdev)) + + "/" + encode_int(minor(stat_buf.st_rdev)); break; case S_IFLNK: inode_type = 'l'; @@ -212,49 +317,36 @@ void scanfile(const string& path) * 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); + len = readlink(fullpath.c_str(), buf, stat_buf.st_size + 1); if (len < 0) { - printf("error reading symlink: %m\n"); + fprintf(stderr, "error reading symlink: %m\n"); } else if (len <= stat_buf.st_size) { buf[len] = '\0'; - printf(" contents=%s\n", buf); + file_info["contents"] = uri_encode(buf); } else if (len > stat_buf.st_size) { - printf("error reading symlink: name truncated\n"); + fprintf(stderr, "error reading symlink: name truncated\n"); } - file_info["contents"] = uri_encode(buf); - delete[] buf; break; case S_IFREG: 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); + file_size = dumpfile(fd, file_info, path, stat_buf); + file_info["size"] = encode_int(file_size); + close(fd); - /* 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); + if (file_size < 0) + return; // error occurred; do not dump file - file_info["size"] = encode_int(stat_buf.st_size); - dumpfile(fd, file_info); - close(fd); + if (file_size != stat_buf.st_size) { + fprintf(stderr, "Warning: Size of %s changed during reading\n", + path.c_str()); + } break; case S_IFDIR: inode_type = 'd'; - recurse = true; break; default: @@ -263,88 +355,387 @@ void scanfile(const string& path) } file_info["type"] = string(1, inode_type); - metadata << "type: " << inode_type << "\n"; + metadata << "name: " << uri_encode(path) << "\n"; dict_output(metadata, file_info); metadata << "\n"; // Break apart metadata listing if it becomes too large. - if (metadata.str().size() > 4096) + if (metadata.str().size() > LBS_METADATA_BLOCK_SIZE) metadata_flush(); +} + +void scanfile(const string& path, bool include) +{ + int fd = -1; + long flags; + struct stat stat_buf; + list refs; + + string true_path; + if (relative_paths) + true_path = path; + else + true_path = "/" + path; + + // Set to true if we should scan through the contents of this directory, + // but not actually back files up + bool scan_only = false; + + // Check this file against the include/exclude list to see if it should be + // considered + for (list::iterator i = includes.begin(); + i != includes.end(); ++i) { + if (path == *i) { + printf("Including %s\n", path.c_str()); + include = true; + } + } + + for (list::iterator i = excludes.begin(); + i != excludes.end(); ++i) { + if (path == *i) { + printf("Excluding %s\n", path.c_str()); + include = false; + } + } + + for (list::iterator i = searches.begin(); + i != searches.end(); ++i) { + if (path == *i) { + printf("Scanning %s\n", path.c_str()); + scan_only = true; + } + } + + if (!include && !scan_only) + return; + + if (lstat(true_path.c_str(), &stat_buf) < 0) { + fprintf(stderr, "lstat(%s): %m\n", path.c_str()); + return; + } + + if ((stat_buf.st_mode & S_IFMT) == S_IFREG) { + /* 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. We + * supply flags to open to to guard against various conditions before + * we can perform an lstat to check that the file is still a regular + * file: + * - 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). However, O_NOATIME may result in EPERM, so if the + * initial open fails, try again without O_NOATIME. */ + fd = open(true_path.c_str(), O_RDONLY|O_NOATIME|O_NOFOLLOW|O_NONBLOCK); + if (fd < 0) { + fd = open(true_path.c_str(), O_RDONLY|O_NOFOLLOW|O_NONBLOCK); + } + if (fd < 0) { + fprintf(stderr, "Unable to open file %s: %m\n", path.c_str()); + return; + } + + /* 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); + + /* Perform the stat call again, and check that we still have a regular + * file. */ + if (fstat(fd, &stat_buf) < 0) { + fprintf(stderr, "fstat: %m\n"); + close(fd); + return; + } + + if ((stat_buf.st_mode & S_IFMT) != S_IFREG) { + fprintf(stderr, "file is no longer a regular file!\n"); + close(fd); + return; + } + } + + dump_inode(path, true_path, stat_buf, fd); + + if (fd >= 0) + close(fd); // If we hit a directory, now that we've written the directory itself, // recursively scan the directory. - if (recurse) - scandir(path); + if ((stat_buf.st_mode & S_IFMT) == S_IFDIR) { + DIR *dir = opendir(true_path.c_str()); + + if (dir == NULL) { + 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; + contents.push_back(filename); + } + + closedir(dir); + + sort(contents.begin(), contents.end()); + + for (vector::iterator i = contents.begin(); + i != contents.end(); ++i) { + const string& filename = *i; + if (path == ".") + scanfile(filename, include); + else + scanfile(path + "/" + filename, include); + } + } } -void scandir(const string& path) +/* Include the specified file path in the backups. Append the path to the + * includes list, and to ensure that we actually see the path when scanning the + * directory tree, add all the parent directories to the search list, which + * means we will scan through the directory listing even if the files + * themselves are excluded from being backed up. */ +void add_include(const char *path) { - DIR *dir = opendir(path.c_str()); + printf("Add: %s\n", path); + /* Was an absolute path specified? If so, we'll need to start scanning + * from the root directory. Make sure that the user was consistent in + * providing either all relative paths or all absolute paths. */ + if (path[0] == '/') { + if (includes.size() > 0 && relative_paths == true) { + fprintf(stderr, + "Error: Cannot mix relative and absolute paths!\n"); + exit(1); + } - if (dir == NULL) { - printf("Error: %m\n"); - return; - } + relative_paths = false; - struct dirent *ent; - vector contents; - while ((ent = readdir(dir)) != NULL) { - string filename(ent->d_name); - if (filename == "." || filename == "..") - continue; - contents.push_back(filename); + // Skip over leading '/' + path++; + } else if (relative_paths == false && path[0] != '/') { + fprintf(stderr, "Error: Cannot mix relative and absolute paths!\n"); + exit(1); } - sort(contents.begin(), contents.end()); + includes.push_back(path); + + /* Split the specified path into directory components, and ensure that we + * descend into all the directories along the path. */ + const char *slash = path; + + if (path[0] == '\0') + return; - for (vector::iterator i = contents.begin(); - i != contents.end(); ++i) { - const string& filename = *i; - scanfile(path + "/" + filename); + while ((slash = strchr(slash + 1, '/')) != NULL) { + string component(path, slash - path); + searches.push_back(component); } +} - closedir(dir); +void usage(const char *program) +{ + fprintf( + stderr, + "Usage: %s [OPTION]... --dest=DEST PATHS...\n" + "Produce backup snapshot of files in SOURCE and store to DEST.\n" + "\n" + "Options:\n" + " --dest=PATH path where backup is to be written [REQUIRED]\n" + " --exclude=PATH exclude files in PATH from snapshot\n" + " --localdb=PATH local backup metadata is stored in PATH\n" + " --filter=COMMAND program through which to filter segment data\n" + " (defaults to \"bzip2 -c\")\n" + " --filter-extension=EXT\n" + " string to append to segment files\n" + " (defaults to \".bz2\")\n" + " --scheme=NAME optional name for this snapshot\n", + program + ); } int main(int argc, char *argv[]) { - block_buf = new char[LBS_BLOCK_SIZE]; + string backup_source = "."; + string backup_dest = ""; + string localdb_dir = ""; + string backup_scheme = ""; + + while (1) { + static struct option long_options[] = { + {"localdb", 1, 0, 0}, // 0 + {"exclude", 1, 0, 0}, // 1 + {"filter", 1, 0, 0}, // 2 + {"filter-extension", 1, 0, 0}, // 3 + {"dest", 1, 0, 0}, // 4 + {"scheme", 1, 0, 0}, // 5 + {NULL, 0, 0, 0}, + }; + + int long_index; + int c = getopt_long(argc, argv, "", long_options, &long_index); + + if (c == -1) + break; - if (argc > 1) { - tss = new TarSegmentStore(argv[1]); + if (c == 0) { + switch (long_index) { + case 0: // --localdb + localdb_dir = optarg; + break; + case 1: // --exclude + if (optarg[0] != '/') + excludes.push_back(optarg); + else + excludes.push_back(optarg + 1); + break; + case 2: // --filter + filter_program = optarg; + break; + case 3: // --filter-extension + filter_extension = optarg; + break; + case 4: // --dest + backup_dest = optarg; + break; + case 5: // --scheme + backup_scheme = optarg; + break; + default: + fprintf(stderr, "Unhandled long option!\n"); + return 1; + } + } else { + usage(argv[0]); + return 1; + } + } + + if (argc < optind + 2) { + usage(argv[0]); + return 1; + } + + searches.push_back("."); + if (optind == argc) { + add_include("."); } else { - tss = new TarSegmentStore("."); + for (int i = optind; i < argc; i++) + add_include(argv[i]); + } + + backup_source = argv[optind]; + + if (backup_dest == "") { + fprintf(stderr, + "Error: Backup destination must be specified with --dest=\n"); + usage(argv[0]); + return 1; + } + + // Default for --localdb is the same as --dest + if (localdb_dir == "") { + localdb_dir = backup_dest; } - try { - scanfile("."); - } catch (IOException e) { - fprintf(stderr, "IOException: %s\n", e.getError().c_str()); + // Dump paths for debugging/informational purposes + { + list::const_iterator i; + + printf("LBS Version: %s\n", lbs_version); + + printf("--dest=%s\n--localdb=%s\n\n", + backup_dest.c_str(), localdb_dir.c_str()); + + printf("Includes:\n"); + for (i = includes.begin(); i != includes.end(); ++i) + printf(" %s\n", i->c_str()); + + printf("Excludes:\n"); + for (i = excludes.begin(); i != excludes.end(); ++i) + printf(" %s\n", i->c_str()); + + printf("Searching:\n"); + for (i = searches.begin(); i != searches.end(); ++i) + printf(" %s\n", i->c_str()); } + tss = new TarSegmentStore(backup_dest); + block_buf = new char[LBS_BLOCK_SIZE]; + + /* Store the time when the backup started, so it can be included in the + * snapshot name. */ + 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); + + /* Open the local database which tracks all objects that are stored + * remotely, for efficient incrementals. Provide it with the name of this + * snapshot. */ + string database_path = localdb_dir + "/localdb.sqlite"; + db = new LocalDb; + db->Open(database_path.c_str(), desc_buf, + backup_scheme.size() ? backup_scheme.c_str() : NULL); + + /* Initialize the stat cache, for skipping over unchanged files. */ + statcache = new StatCache; + statcache->Open(localdb_dir.c_str(), desc_buf); + + scanfile(".", false); + metadata_flush(); const string md = metadata_root.str(); LbsObject *root = new LbsObject; - root->set_group("root"); + root->set_group("metadata"); root->set_data(md.data(), md.size()); root->write(tss); root->checksum(); - segment_list.insert(root->get_ref().get_segment()); - string r = root->get_ref().to_string(); - printf("\nroot: %s\n\n", r.c_str()); + + string backup_root = root->get_ref().to_string(); delete root; - printf("segments:\n"); - for (std::set::iterator i = segment_list.begin(); - i != segment_list.end(); ++i) { - printf(" %s\n", i->c_str()); - } + db->Close(); + + statcache->Close(); + delete statcache; tss->sync(); + tss->dump_stats(); delete tss; + /* 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. */ + string desc_filename = backup_dest + "/snapshot-"; + if (backup_scheme.size() > 0) + desc_filename += backup_scheme + "-"; + desc_filename = desc_filename + desc_buf + ".lbs"; + std::ofstream descriptor(desc_filename.c_str()); + + descriptor << "Format: LBS Snapshot v0.1\n"; + descriptor << "Producer: LBS " << lbs_version << "\n"; + strftime(desc_buf, sizeof(desc_buf), "%Y-%m-%d %H:%M:%S %z", &time_buf); + descriptor << "Date: " << desc_buf << "\n"; + if (backup_scheme.size() > 0) + descriptor << "Scheme: " << backup_scheme << "\n"; + descriptor << "Root: " << backup_root << "\n"; + + descriptor << "Segments:\n"; + for (std::set::iterator i = segment_list.begin(); + i != segment_list.end(); ++i) { + descriptor << " " << *i << "\n"; + } + return 0; }