1 /* Recursively descend the filesystem and visit each file. */
30 static TarSegmentStore *tss = NULL;
32 /* Buffer for holding a single block of data read from a file. */
33 static const size_t LBS_BLOCK_SIZE = 1024 * 1024;
34 static char *block_buf;
36 static const size_t LBS_METADATA_BLOCK_SIZE = 65536;
38 /* Contents of the root object. This will contain a set of indirect links to
39 * the metadata objects. */
40 std::ostringstream metadata_root;
42 /* Buffer for building up metadata. */
43 std::ostringstream metadata;
45 /* Keep track of all segments which are needed to reconstruct the snapshot. */
46 std::set<string> segment_list;
48 void scandir(const string& path);
50 /* Ensure contents of metadata are flushed to an object. */
53 string m = metadata.str();
57 /* Write current metadata information to a new object. */
58 LbsObject *meta = new LbsObject;
59 meta->set_group("root");
60 meta->set_data(m.data(), m.size());
64 /* Write a reference to this block in the root. */
65 ObjectReference ref = meta->get_ref();
66 metadata_root << "@" << ref.to_string() << "\n";
67 segment_list.insert(ref.get_segment());
74 /* Read data from a file descriptor and return the amount of data read. A
75 * short read (less than the requested size) will only occur if end-of-file is
77 size_t file_read(int fd, char *buf, size_t maxlen)
79 size_t bytes_read = 0;
82 ssize_t res = read(fd, buf, maxlen);
86 throw IOException("file_read: error reading");
87 } else if (res == 0) {
99 /* Read the contents of a file (specified by an open file descriptor) and copy
100 * the data to the store. */
101 void dumpfile(int fd, dictionary &file_info)
103 struct stat stat_buf;
104 fstat(fd, &stat_buf);
106 list<string> object_list;
108 if ((stat_buf.st_mode & S_IFMT) != S_IFREG) {
109 fprintf(stderr, "file is no longer a regular file!\n");
113 /* The index data consists of a sequence of pointers to the data blocks
114 * that actually comprise the file data. This level of indirection is used
115 * so that the same data block can be used in multiple files, or multiple
116 * versions of the same file. */
119 size_t bytes = file_read(fd, block_buf, LBS_BLOCK_SIZE);
123 hash.process(block_buf, bytes);
125 // tarstore processing
126 LbsObject *o = new LbsObject;
127 o->set_group("data");
128 o->set_data(block_buf, bytes);
130 object_list.push_back(o->get_name());
131 segment_list.insert(o->get_ref().get_segment());
137 file_info["checksum"] = hash.checksum_str();
139 /* For files that only need to be broken apart into a few objects, store
140 * the list of objects directly. For larger files, store the data
141 * out-of-line and provide a pointer to the indrect object. */
142 if (object_list.size() < 8) {
143 string blocklist = "";
144 for (list<string>::iterator i = object_list.begin();
145 i != object_list.end(); ++i) {
146 if (i != object_list.begin())
150 file_info["data"] = blocklist;
152 string blocklist = "";
153 for (list<string>::iterator i = object_list.begin();
154 i != object_list.end(); ++i) {
155 blocklist += *i + "\n";
158 LbsObject *i = new LbsObject;
159 i->set_group("indirect");
160 i->set_data(blocklist.data(), blocklist.size());
162 file_info["data"] = "@" + i->get_name();
163 segment_list.insert(i->get_ref().get_segment());
168 void scanfile(const string& path)
172 struct stat stat_buf;
177 // Set to true if the item is a directory and we should recursively scan
178 bool recurse = false;
180 dictionary file_info;
182 lstat(path.c_str(), &stat_buf);
184 printf("%s\n", path.c_str());
186 metadata << "name: " << uri_encode(path) << "\n";
188 file_info["mode"] = encode_int(stat_buf.st_mode & 07777);
189 file_info["atime"] = encode_int(stat_buf.st_atime);
190 file_info["ctime"] = encode_int(stat_buf.st_ctime);
191 file_info["mtime"] = encode_int(stat_buf.st_mtime);
192 file_info["user"] = encode_int(stat_buf.st_uid);
193 file_info["group"] = encode_int(stat_buf.st_gid);
197 switch (stat_buf.st_mode & S_IFMT) {
213 /* Use the reported file size to allocate a buffer large enough to read
214 * the symlink. Allocate slightly more space, so that we ask for more
215 * bytes than we expect and so check for truncation. */
216 buf = new char[stat_buf.st_size + 2];
217 len = readlink(path.c_str(), buf, stat_buf.st_size + 1);
219 fprintf(stderr, "error reading symlink: %m\n");
220 } else if (len <= stat_buf.st_size) {
222 file_info["contents"] = uri_encode(buf);
223 } else if (len > stat_buf.st_size) {
224 fprintf(stderr, "error reading symlink: name truncated\n");
232 /* Be paranoid when opening the file. We have no guarantee that the
233 * file was not replaced between the stat() call above and the open()
234 * call below, so we might not even be opening a regular file. That
235 * the file descriptor refers to a regular file is checked in
236 * dumpfile(). But we also supply flags to open to to guard against
237 * various conditions before we can perform that verification:
238 * - O_NOFOLLOW: in the event the file was replaced by a symlink
239 * - O_NONBLOCK: prevents open() from blocking if the file was
241 * We also add in O_NOATIME, since this may reduce disk writes (for
243 fd = open(path.c_str(), O_RDONLY|O_NOATIME|O_NOFOLLOW|O_NONBLOCK);
245 /* Drop the use of the O_NONBLOCK flag; we only wanted that for file
247 flags = fcntl(fd, F_GETFL);
248 fcntl(fd, F_SETFL, flags & ~O_NONBLOCK);
250 file_info["size"] = encode_int(stat_buf.st_size);
251 dumpfile(fd, file_info);
261 fprintf(stderr, "Unknown inode type: mode=%x\n", stat_buf.st_mode);
265 file_info["type"] = string(1, inode_type);
267 dict_output(metadata, file_info);
270 // Break apart metadata listing if it becomes too large.
271 if (metadata.str().size() > LBS_METADATA_BLOCK_SIZE)
274 // If we hit a directory, now that we've written the directory itself,
275 // recursively scan the directory.
280 void scandir(const string& path)
282 DIR *dir = opendir(path.c_str());
285 fprintf(stderr, "Error: %m\n");
290 vector<string> contents;
291 while ((ent = readdir(dir)) != NULL) {
292 string filename(ent->d_name);
293 if (filename == "." || filename == "..")
295 contents.push_back(filename);
298 sort(contents.begin(), contents.end());
300 for (vector<string>::iterator i = contents.begin();
301 i != contents.end(); ++i) {
302 const string& filename = *i;
303 scanfile(path + "/" + filename);
309 int main(int argc, char *argv[])
311 block_buf = new char[LBS_BLOCK_SIZE];
314 tss = new TarSegmentStore(argv[1]);
316 tss = new TarSegmentStore(".");
321 } catch (IOException e) {
322 fprintf(stderr, "IOException: %s\n", e.getError().c_str());
326 const string md = metadata_root.str();
328 LbsObject *root = new LbsObject;
329 root->set_group("root");
330 root->set_data(md.data(), md.size());
334 segment_list.insert(root->get_ref().get_segment());
335 string r = root->get_ref().to_string();
336 printf("\nroot: %s\n\n", r.c_str());
339 printf("segments:\n");
340 for (std::set<string>::iterator i = segment_list.begin();
341 i != segment_list.end(); ++i) {
342 printf(" %s\n", i->c_str());