Update Changelog.md

Tweaked the default hash function and hash-map-bucket-size.

CMakeLists.txt

@@ -1,7 +1,7 @@
-cmake_minimum_required(VERSION 3.7)
+cmake_minimum_required(VERSION 3.10)
 project(SimpleArchiver C)
 
-set(SimpleArchiver_VERSION 1.0)
+set(SimpleArchiver_VERSION 1.7)
 
 set(SimpleArchiver_SOURCES
     src/main.c

Changelog.md

@@ -2,6 +2,49 @@
 
 ## Upcoming Changes
 
+## Version 1.7
+
+Refactor the internal hash-map data structure.
+
+Minor update to CMakeLists.txt.
+
+## Version 1.6
+
+Enforce "safe-links" on extraction by ensuring every extracted symlink actually
+points to a file in the archive. Additionally any extracted symlinks that don't
+point to a valid destination is removed. This "enforce safe-links on extract"
+can be disabled with the "--no-safe-links" option.
+
+Add "--preserve-symlinks" option that will verbatim store the symlinks' target.
+Not recommended if symlinks are pointing to absolute paths, which will be
+clobbered on extraction to a different directory unless if "--no-safe-links" is
+specified on extraction.
+
+## Version 1.5
+
+Previous file-format-v1 implementation of "safe links" still created a symlink
+if a relative or absolute link existed in the file. This version fixes this, and
+prevents invalid symlinks from being created. (This check is only done if the
+bit-flag is set in the file as mentioned in the file-format spec for v1 files.)
+
+## Version 1.4
+
+Do "safe links" behavior by default: symlinks pointing to outside of archived
+files (or invalid symlinks) should not be included in the archive, unless if the
+option "--no-safe-links" is specified. This is supported in both v0 and v1 file
+formats.
+
+## Version 1.3
+
+Prevent `simplearchiver` from busy-waiting during non-blocking IO by sleeping
+in "EWOULDBLOCK" conditions. This results in less consumed cpu time by the
+process, especially during compression.
+
+## Version 1.2
+
+Proper handling of Ctrl+C (SIGINT). This prevents temporary files from
+persisting by doing a proper cleanup before stopping the program.
+
 ## Version 1.1
 
 More robust handling of de/compression process (handling SIGPIPE).

README.md

@@ -27,6 +27,8 @@ API calls.
     --overwrite-create : allows overwriting an archive file
     --overwrite-extract : allows overwriting when extracting
     --no-abs-symlink : do not store absolute paths for symlinks
+    --preserve-symlinks : preserve the symlink's path on archive creation instead of deriving abs/relative paths, ignores "--no-abs-symlink" (It is not recommended to use this option, as absolute-path-symlinks may be clobbered on extraction)
+    --no-safe-links : keep symlinks that link to outside archive contents
     --temp-files-dir <dir> : where to store temporary files created when compressing (defaults to current working directory)
     --write-version <version> : Force write version file format (default 1)
     --chunk-min-size <bytes> : v1 file format minimum chunk size (default 4194304 or 4MiB)
@@ -38,6 +40,11 @@ API calls.
 Note that `--compressor` and `--decompressor` cmds must accept data from stdin
 and return processed data to stdout.
 
+## Using the Cosmopolitan-Compiled Version
+
+Note that on Linux, the `actually_portable_simplearchiver` binaries may attempt
+to open via Wine (if Wine is installed). [A workaround is mentioned here.](https://github.com/jart/cosmopolitan/blob/master/README.md#linux)
+
 ## Changes
 
 See the [Changelog](https://git.seodisparate.com/stephenseo/SimpleArchiver/src/branch/main/Changelog.md).

file_format.md

@@ -57,6 +57,11 @@ Following the file-count bytes, the following bytes are added for each file:
         2. The second bit is "other execute permission".
         3. The third bit is UNSET if relative links are preferred, and is SET
            if absolute links are preferred.
+        4. The fourth bit is set if this file/symlink-entry is invalid and must
+           be skipped. Ignore following bytes after these 4 bytes bit-flags in
+           this specification and skip to the next entry; if marked invalid,
+           the following specification bytes for this file/symlink entry must
+           not exist.
     3. The third byte.
         1. Currently unused.
     4. The fourth byte.
@@ -128,6 +133,9 @@ Following the link-count bytes, the following bytes are added for each symlink:
     2. The second byte.
         1. The first bit is "other write permission".
         2. The second bit is "other execute permission".
+        3. If this bit is set, then this entry is marked invalid. The link name
+           will be preserved in this entry, but the following link target paths
+           will be set to zero-length and will not be stored.
 2. 2 bytes 16-bit unsigned integer "link name" in big-endian. This does not
    include the NULL at the end of the string. Must not be zero.
 3. X bytes of link-name (length defined by previous value). Is a NULL-terminated

src/archiver.h

@@ -52,7 +52,8 @@ typedef enum SDArchiverStateReturns {
   SDAS_FAILED_TO_CREATE_MAP,
   SDAS_FAILED_TO_EXTRACT_SYMLINK,
   SDAS_FAILED_TO_CHANGE_CWD,
-  SDAS_INVALID_WRITE_VERSION
+  SDAS_INVALID_WRITE_VERSION,
+  SDAS_SIGINT
 } SDArchiverStateReturns;
 
 /// Returned pointer must not be freed.
@@ -108,4 +109,9 @@ char *simple_archiver_file_abs_path(const char *filename);
 /// Returns 5 if "filepath" is NULL.
 int simple_archiver_validate_file_path(const char *filepath);
 
+/// Removes links from "links_list" in cwd if it is not valid or does not point
+/// to a file in "files_map".
+void simple_archiver_safe_links_enforce(SDArchiverLinkedList *links_list,
+                                        SDArchiverHashMap *files_map);
+
 #endif

src/data_structures/hash_map.c

@@ -76,19 +76,17 @@ int simple_archiver_hash_map_internal_pick_in_list(void *data, void *ud) {
 
 uint64_t simple_archiver_hash_default_fn(const void *key, size_t key_size) {
   uint64_t seed = 0;
-  uint64_t temp = 0;
+  uint64_t temp;
-  size_t count = 0;
   for (size_t idx = 0; idx < key_size; ++idx) {
-    temp |= ((uint64_t) * ((uint8_t *)key + idx)) << (8 * count);
+    temp = (uint64_t)(((uint8_t*)key)[idx]) + seed;
-    ++count;
+    if (idx % 3 == 0) {
-    if (count >= 8) {
+      temp ^= 0xA5A538A5A9B5A5A5;
-      count = 0;
+    } else if (idx % 3 == 1) {
-      seed += temp;
+      temp ^= 0xD7A58BD7A58BD7AA;
-      temp = 0;
+    } else {
+      temp ^= 0x8B7A8B8B87CB8B84;
     }
-  }
+    seed += simple_archiver_algo_lcg_defaults(temp);
-  if (temp != 0) {
-    seed += temp;
   }
 
   return simple_archiver_algo_lcg_defaults(seed);
@@ -106,7 +104,7 @@ int simple_archiver_hash_map_internal_rehash(SDArchiverHashMap *hash_map) {
   }
   SDArchiverHashMap new_hash_map;
   new_hash_map.hash_fn = hash_map->hash_fn;
-  new_hash_map.buckets_size = hash_map->buckets_size * 2;
+  new_hash_map.buckets_size = (hash_map->buckets_size - 1) * 2 + 1;
   // Pointers have the same size (at least on the same machine), so
   // sizeof(void*) should be ok.
   new_hash_map.buckets = malloc(sizeof(void *) * new_hash_map.buckets_size);
@@ -154,7 +152,7 @@ SDArchiverHashMap *simple_archiver_hash_map_init_custom_hasher(
     uint64_t (*hash_fn)(const void *, size_t)) {
   SDArchiverHashMap *hash_map = malloc(sizeof(SDArchiverHashMap));
   hash_map->hash_fn = hash_fn;
-  hash_map->buckets_size = SC_SA_DS_HASH_MAP_START_BUCKET_SIZE;
+  hash_map->buckets_size = SC_SA_DS_HASH_MAP_START_BUCKET_SIZE + 1;
   // Pointers have the same size (at least on the same machine), so
   // sizeof(void*) should be ok.
   hash_map->buckets = malloc(sizeof(void *) * hash_map->buckets_size);

src/data_structures/test.c

@@ -219,6 +219,59 @@ int main(void) {
     simple_archiver_hash_map_free(&hash_map);
   }
 
+  // Test hashing.
+  //{
+  //  printf("Distribution of 13 over 33...\n");
+  //  unsigned int counts[33];
+  //  memset(counts, 0, sizeof(unsigned int) * 33);
+
+  //  uint64_t hash;
+
+  //  hash = simple_archiver_hash_default_fn("/", 2);
+  //  printf("%s in bucket %lu (%lu)\n", "/", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/faq", 5);
+  //  printf("%s in bucket %lu (%lu)\n", "/faq", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/FAQ", 5);
+  //  printf("%s in bucket %lu (%lu)\n", "/FAQ", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/url", 5);
+  //  printf("%s in bucket %lu (%lu)\n", "/url", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/home", 6);
+  //  printf("%s in bucket %lu (%lu)\n", "/home", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/blog", 6);
+  //  printf("%s in bucket %lu (%lu)\n", "/blog", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/test", 6);
+  //  printf("%s in bucket %lu (%lu)\n", "/test", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/menu", 6);
+  //  printf("%s in bucket %lu (%lu)\n", "/menu", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/posts", 7);
+  //  printf("%s in bucket %lu (%lu)\n", "/posts", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/about", 7);
+  //  printf("%s in bucket %lu (%lu)\n", "/about", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/media", 7);
+  //  printf("%s in bucket %lu (%lu)\n", "/media", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/social", 8);
+  //  printf("%s in bucket %lu (%lu)\n", "/social", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+  //  hash = simple_archiver_hash_default_fn("/projects", 10);
+  //  printf("%s in bucket %lu (%lu)\n", "/projects", hash % 33, hash);
+  //  counts[hash % 33] += 1;
+
+  //  for (unsigned int idx = 0; idx < 33; ++idx) {
+  //    printf("Bucket %u: %u\n", idx, counts[idx]);
+  //  }
+  //}
+
   // Test PriorityHeap.
   {
     SDArchiverPHeap *priority_heap = simple_archiver_priority_heap_init();

src/parser.c

@@ -168,6 +168,15 @@ void simple_archiver_print_usage(void) {
   fprintf(stderr, "--overwrite-extract : allows overwriting when extracting\n");
   fprintf(stderr,
           "--no-abs-symlink : do not store absolute paths for symlinks\n");
+  fprintf(
+      stderr,
+      "--preserve-symlinks : preserve the symlink's path on archive creation "
+      "instead of deriving abs/relative paths, ignores \"--no-abs-symlink\" "
+      "(It is not recommended to use this option, as absolute-path-symlinks "
+      "may be clobbered on extraction)\n");
+  fprintf(stderr,
+          "--no-safe-links : keep symlinks that link to outside archive "
+          "contents\n");
   fprintf(stderr,
           "--temp-files-dir <dir> : where to store temporary files created "
           "when compressing (defaults to current working directory)\n");
@@ -303,6 +312,13 @@ int simple_archiver_parse_args(int argc, const char **argv,
         out->flags |= 0x8;
       } else if (strcmp(argv[0], "--no-abs-symlink") == 0) {
         out->flags |= 0x20;
+      } else if (strcmp(argv[0], "--preserve-symlinks") == 0) {
+        out->flags |= 0x100;
+      } else if (strcmp(argv[0], "--no-safe-links") == 0) {
+        out->flags |= 0x80;
+        fprintf(stderr,
+                "NOTICE: Disabling safe-links, symlinks that point to outside "
+                "archived files will be preserved!\n");
       } else if (strcmp(argv[0], "--temp-files-dir") == 0) {
         if (argc < 2) {
           fprintf(stderr, "ERROR: --temp-files-dir is missing an argument!\n");

src/parser.h

@@ -36,6 +36,8 @@ typedef struct SDArchiverParsed {
   /// 0b xxx1 xxxx - Create archive to stdout or read archive from stdin.
   /// 0b xx1x xxxx - Do not save absolute paths for symlinks.
   /// 0b x1xx xxxx - Sort files by size before archiving.
+  /// 0b 1xxx xxxx - No safe links.
+  /// 0b xxxx xxx1 xxxx xxxx - Preserve symlink target.
   uint32_t flags;
   /// Null-terminated string.
   char *filename;

src/test.c

@@ -256,6 +256,11 @@ int main(void) {
     CHECK_STREQ(rel_path, "../other/dir/");
     simple_archiver_helper_cleanup_c_string(&rel_path);
 
+    rel_path = simple_archiver_filenames_to_relative_path(
+        "/one/two/three/", "/one/two/three/four");
+    CHECK_STREQ(rel_path, "four");
+    simple_archiver_helper_cleanup_c_string(&rel_path);
+
     CHECK_FALSE(simple_archiver_validate_file_path("Local/Path"));
     CHECK_TRUE(simple_archiver_validate_file_path("/Abs/Path"));
     CHECK_TRUE(simple_archiver_validate_file_path("Local/../../not/really"));