Merge pull request 'docs: rsync feature compatibility matrix' (#199) from docs/rsync-compat into dev

Reviewed-on: #199

RSYNC_COMPAT.md

@@ -0,0 +1,274 @@
+# Rsync Feature Compatibility
+
+This document maps rsync's full feature set to FastSync's current implementation status.
+
+## Summary
+
+| Status | Count | Description |
+|--------|-------|-------------|
+| ✅ Implemented | 39 | Feature works end-to-end |
+| 🔀 Alt Arg | 5 | Functionality exists but under different flag/semantics |
+| ⚠️ Partial | 30 | Flag parsed/stored but behavior incomplete |
+| ❌ Not Implemented | 62 | Flag not recognized or no behavior |
+| **Total** | **136** | |
+
+---
+
+## 1. General Options
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-a`, `--archive` | Archive mode is -rlptgoD | 🔀 Alt Arg | Maps to -c -m -M (compression + multithread + metadata) |
+| `-v`, `--verbose` | Increase verbosity | ✅ Implemented | Sets `log_level=DEBUG` |
+| `-q`, `--quiet` | Suppress non-error messages | ✅ Implemented | `quiet` config field |
+| `-h`, `--help` | Show help | ✅ Implemented | Prints usage and exits |
+| `-V`, `--version` | Print version | ❌ Not Implemented | |
+| `--info=FLAGS` | Fine-grained info verbosity | ⚠️ Partial | `info_level` stored, not wired |
+| `--debug=FLAGS` | Fine-grained debug verbosity | ⚠️ Partial | `debug_level` stored, not wired |
+| `--stderr=MODE` | Change stderr output mode | ❌ Not Implemented | |
+| `--no-motd` | Suppress daemon MOTD | ❌ Not Implemented | |
+| `--exclude=PATTERN` | Exclude files matching pattern | ✅ Implemented | Glob matching in scanner |
+| `--include=PATTERN` | Include files matching pattern | ✅ Implemented | Glob matching in scanner |
+| `-C`, `--cvs-exclude` | Auto-ignore CVS files | ⚠️ Partial | `cvs_exclude` stored, not wired |
+
+## 2. Modifying Output
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `--stats` | Give transfer stats | ✅ Implemented | Prints file/byte counts |
+| `-h`, `--human-readable` | Human-readable numbers | ⚠️ Partial | `human_readable` stored, not wired |
+| `-i`, `--itemize-changes` | Per-file change summary | ⚠️ Partial | `itemize_changes` stored, not wired |
+| `--progress` | Show progress | ✅ Implemented | Progress callback in sender |
+| `-P` | Same as --partial --progress | ❌ Not Implemented | |
+| `--out-format=FORMAT` | Custom output format | ⚠️ Partial | `out_format` stored, not wired |
+| `--log-file=FILE` | Log to file | ✅ Implemented | `log_file` config field |
+| `--log-file-format=FMT` | Log format | ❌ Not Implemented | |
+| `--8-bit-output` | Leave high-bit chars unescaped | ❌ Not Implemented | |
+| `--list-only` | List files instead of copying | ⚠️ Partial | `list_only` stored, not wired |
+
+## 3. File Selection
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `--exclude-from=FILE` | Read exclude patterns from file | ✅ Implemented | Reads patterns from file |
+| `--include-from=FILE` | Read include patterns from file | ✅ Implemented | Reads patterns from file |
+| `--filter=RULE` | Add file-filtering rule | ⚠️ Partial | `filters` ArrayList stored, not wired |
+| `--files-from=FILE` | Read source file list from file | ⚠️ Partial | `files_from` stored, not wired |
+| `-0`, `--from0` | Delimit *-from files with NULs | ❌ Not Implemented | |
+| `--max-size=SIZE` | Skip files larger than SIZE | ✅ Implemented | `max_size` in scanner |
+| `--min-size=SIZE` | Skip files smaller than SIZE | ✅ Implemented | `min_size` in scanner |
+| `-I`, `--ignore-times` | Don't skip files matching size+time | ❌ Not Implemented | |
+| `--size-only` | Skip based on size only | ❌ Not Implemented | |
+| `-@`, `--modify-window=NUM` | Mod-time comparison accuracy | ❌ Not Implemented | |
+| `--existing` | Skip creating new files on receiver | ❌ Not Implemented | |
+| `--ignore-existing` | Skip updating existing files | ❌ Not Implemented | |
+| `--remove-source-files` | Sender removes synced files | ❌ Not Implemented | |
+
+## 4. Directory Options
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-r`, `--recursive` | Recurse into directories | ✅ Implemented | Default behavior |
+| `-R`, `--relative` | Use relative path names | ⚠️ Partial | `relative` stored, not wired |
+| `--no-implied-dirs` | Don't send implied dirs with -R | ❌ Not Implemented | |
+| `-d`, `--dirs` | Transfer dirs without recursing | ❌ Not Implemented | |
+| `--mkpath` | Create missing path components | ❌ Not Implemented | |
+
+## 5. Transfer Modifications
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-u`, `--update` | Skip files newer on receiver | ⚠️ Partial | `update` stored, not wired |
+| `--inplace` | Update files in-place | ✅ Implemented | Direct write mode |
+| `--append` | Append data to shorter files | ⚠️ Partial | `append` stored, not wired |
+| `--append-verify` | Append with old-data checksum | ⚠️ Partial | `append_verify` stored, not wired |
+| `-W`, `--whole-file` | Copy whole file (no delta) | ❌ Not Implemented | |
+| `--block-size=SIZE` | Force checksum block-size | ⚠️ Partial | Parsed as `--delta-block`; controls delta transfer block size |
+
+## 6. Destination Handling
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-n`, `--dry-run` | Trial run with no changes | ✅ Implemented | `dry_run` config field |
+| `-b`, `--backup` | Make backups of overwritten files | ✅ Implemented | Backup before overwrite |
+| `--backup-dir=DIR` | Backup directory hierarchy | ✅ Implemented | `backup_dir` config field |
+| `--suffix=SUFFIX` | Backup suffix (default ~) | ✅ Implemented | `suffix` config field |
+| `--delay-updates` | Put updated files in place at end | ❌ Not Implemented | |
+
+## 7. Deletion
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `--delete` | Delete extraneous files from dest | ✅ Implemented | `use_delete` config field |
+| `--delete-before` | Delete before transfer | ⚠️ Partial | `delete_before` stored, not wired |
+| `--delete-during` | Delete during transfer | ❌ Not Implemented | |
+| `--delete-delay` | Find deletions during, delete after | ❌ Not Implemented | |
+| `--delete-after` | Delete after transfer | ⚠️ Partial | `delete_after` stored, not wired |
+| `--delete-excluded` | Also delete excluded files | ⚠️ Partial | `delete_excluded` stored, not wired |
+| `--max-delete=NUM` | Max files to delete | ⚠️ Partial | `max_delete` stored, not wired |
+| `--ignore-errors` | Delete even with I/O errors | ❌ Not Implemented | |
+| `--force` | Force deletion of non-empty dirs | ❌ Not Implemented | |
+| `--prune-empty-dirs` | Prune empty dir chains | ⚠️ Partial | `prune_empty_dirs` stored, not wired |
+
+## 8. Metadata Preservation
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-M`, `--preserve` | Preserve file metadata | ✅ Implemented | Mode, uid, gid, mtime |
+| `-p`, `--perms` | Preserve permissions | 🔀 Alt Arg | `-p` means SSH port; permissions preserved via `-M`/`--preserve` |
+| `-o`, `--owner` | Preserve owner | ✅ Implemented | Part of -M |
+| `-g`, `--group` | Preserve group | ✅ Implemented | Part of -M |
+| `-t`, `--times` | Preserve modification times | ✅ Implemented | Part of -M |
+| `-E`, `--executability` | Preserve executability | ❌ Not Implemented | |
+| `--chmod=CHMOD` | Affect file permissions | ❌ Not Implemented | |
+| `-A`, `--acls` | Preserve ACLs | ⚠️ Partial | `preserve_acls` stored, not wired |
+| `-X`, `--xattrs` | Preserve extended attributes | ⚠️ Partial | `preserve_xattrs` stored, not wired |
+| `-H`, `--hard-links` | Preserve hard links | ⚠️ Partial | `preserve_hard_links` stored, not wired |
+| `-D` | Same as --devices --specials | 🔀 Alt Arg | Maps to --devices only (no --specials) |
+| `--devices` | Preserve device files | ⚠️ Partial | `preserve_devices` stored, not wired |
+| `--specials` | Preserve special files | ❌ Not Implemented | |
+| `--copy-devices` | Copy device contents as file | ❌ Not Implemented | |
+| `--write-devices` | Write to devices as files | ❌ Not Implemented | |
+| `-U`, `--atimes` | Preserve access times | ❌ Not Implemented | |
+| `-N`, `--crtimes` | Preserve create times | ❌ Not Implemented | |
+| `-O`, `--omit-dir-times` | Omit dirs from --times | ❌ Not Implemented | |
+| `-J`, `--omit-link-times` | Omit symlinks from --times | ❌ Not Implemented | |
+| `--super` | Receiver attempts super-user activities | ❌ Not Implemented | |
+| `--fake-super` | Store/recover privileged attrs via xattrs | ❌ Not Implemented | |
+
+## 9. Symlink Handling
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-l`, `--links` | Copy symlinks as symlinks | ⚠️ Partial | Scanner includes symlinks; target path not transmitted |
+| `-L`, `--copy-links` | Transform symlink to referent | ✅ Implemented | `copy_links` config field |
+| `--copy-unsafe-links` | Transform unsafe symlinks | ✅ Implemented | `copy_unsafe_links` config field |
+| `--safe-links` | Ignore symlinks outside tree | ✅ Implemented | `safe_links` config field |
+| `--munge-links` | Munge symlinks for safety | ❌ Not Implemented | |
+| `-k`, `--copy-dirlinks` | Transform symlink to dir | ❌ Not Implemented | |
+| `-K`, `--keep-dirlinks` | Treat symlinked dir as dir | ❌ Not Implemented | |
+
+## 10. Sparse & Device
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-S`, `--sparse` | Sparse block handling | ✅ Implemented | `preserve_sparse` config field |
+| `--preallocate` | Allocate dest files before writing | ❌ Not Implemented | |
+
+## 11. Checksum & Comparison
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-c`, `--checksum` | Skip based on checksum | 🔀 Alt Arg | `-c` means compression; `--checksum` stored and forwarded to scanner |
+| `--checksum-choice=STR` | Choose checksum algorithm | ❌ Not Implemented | xxHash used internally |
+| `--compare-dest=DIR` | Compare dest files relative to DIR | ⚠️ Partial | `compare_dest` stored, not wired |
+| `--copy-dest=DIR` | Include copies of unchanged files | ⚠️ Partial | `copy_dest` stored, not wired |
+| `--link-dest=DIR` | Hardlink to files when unchanged | ⚠️ Partial | `link_dest` stored, not wired |
+| `--fuzzy`, `--no-fuzzy` | Find similar file for basis | ❌ Not Implemented | |
+
+## 12. Compression
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-z`, `--compress` | Compress file data | 🔀 Alt Arg | Always uses zstd (rsync supports multiple algorithms) |
+| `--compress-choice=STR` | Choose compression algorithm | ⚠️ Partial | `compress_choice` stored, always zstd |
+| `--compress-level=NUM` | Set compression level | ✅ Implemented | 1-22, default 5 |
+| `--compress-threads=NUM` | Set compression threads | ❌ Not Implemented | |
+| `--skip-compress=LIST` | Skip compress for suffixes | ❌ Not Implemented | Internal skip for hardcoded types; not user-configurable |
+
+## 13. Connectivity
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `-e`, `--rsh=COMMAND` | Remote shell to use | ✅ Implemented | SSH transport support |
+| `--rsync-path=PROGRAM` | rsync binary on remote | ✅ Implemented | `rsync_path` config field |
+| `--port=PORT` | Alternate daemon port | ✅ Implemented | `server_port` config field |
+| `--sockopts=OPTIONS` | Custom TCP options | ❌ Not Implemented | |
+| `--blocking-io` | Use blocking I/O for remote shell | ❌ Not Implemented | |
+| `--outbuf=N\|L\|B` | Set output buffering | ❌ Not Implemented | |
+| `--address=ADDRESS` | Bind address for outgoing socket | ✅ Implemented | `address` config field |
+| `-4`, `--ipv4` | Prefer IPv4 | ✅ Implemented | `ipv4` config field |
+| `-6`, `--ipv6` | Prefer IPv6 | ✅ Implemented | `ipv6` config field |
+
+## 14. Daemon Mode
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `--daemon` | Run as rsync daemon | ⚠️ Partial | `daemon` stored, not wired |
+| `--config=FILE` | Alternate rsyncd.conf file | ⚠️ Partial | `daemon_config` stored, not wired |
+| `--dparam=OVERRIDE` | Override global daemon config | ❌ Not Implemented | |
+| `--no-detach` | Don't detach from parent | ❌ Not Implemented | |
+| `--password-file=FILE` | Read daemon password from file | ❌ Not Implemented | |
+| `--early-input=FILE` | Use FILE for daemon early exec | ❌ Not Implemented | |
+
+## 15. Safety & Security
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| Path escape detection | Ensure files stay within root | ✅ Implemented | `has_path_traversal()` + realpath |
+| Symlink-safe delete | Skip symlinks in delete walk | ✅ Implemented | `delete_extras_walk()` |
+| Protocol version check | Verify compatible versions | ✅ Implemented | `config_receive()` |
+| Max data/string/chunk sizes | Prevent OOM attacks | ✅ Implemented | Per-message limits |
+| Per-connection memory limit | 1GB per connection | ✅ Implemented | `MAX_CONNECTION_MEMORY` |
+| `--trust-sender` | Trust remote sender's file list | ❌ Not Implemented | |
+| `--old-args` | Disable modern arg protection | ❌ Not Implemented | |
+| `--ignore-missing-args` | Ignore missing source args | ❌ Not Implemented | |
+| `--delete-missing-args` | Delete missing source args | ❌ Not Implemented | |
+
+## 16. Batch Operations
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `--write-batch=FILE` | Write batched update to file | ❌ Not Implemented | |
+| `--only-write-batch=FILE` | Write batch without updating dest | ❌ Not Implemented | |
+| `--read-batch=FILE` | Read batched update from file | ❌ Not Implemented | |
+
+## 17. Advanced
+
+| Flag | Rsync Description | FastSync Status | Notes |
+|------|-------------------|-----------------|-------|
+| `--stop-after=MINS` | Stop after N minutes | ❌ Not Implemented | |
+| `--stop-at=TIME` | Stop at specified time | ❌ Not Implemented | |
+| `--fsync` | Fsync every written file | ❌ Not Implemented | |
+| `--protocol=NUM` | Force older protocol version | ❌ Not Implemented | |
+| `--iconv=CONVERT_SPEC` | Charset conversion | ❌ Not Implemented | |
+| `--checksum-seed=NUM` | Set checksum seed | ❌ Not Implemented | |
+| `-s`, `--secluded-args` | Use protocol to send args | ❌ Not Implemented | |
+| `--no-OPTION` | Turn off implied option | ❌ Not Implemented | |
+
+---
+
+## Recommendations: Top Features to Implement Next
+
+Ranked by user demand, implementation complexity, and interoperability impact:
+
+| Priority | Feature | Effort | Impact |
+|----------|---------|--------|--------|
+| 1 | `--whole-file` / `-W` | Low | High — users expect opt-out of delta |
+| 2 | `--ignore-times` / `-I` | Low | Medium — useful for forcing re-transfer |
+| 3 | `--size-only` | Low | Medium — common migration scenario |
+| 4 | `--existing` / `--ignore-existing` | Low | Medium — common sync patterns |
+| 5 | `--remove-source-files` | Low | High — common for moves/backup |
+| 6 | `--delete-during` | Medium | High — performance improvement |
+| 7 | `--delay-updates` | Medium | High — atomic updates |
+| 8 | `--chmod` | Low | Medium — permission flexibility |
+| 9 | `--executability` / `-E` | Low | Low — simple flag |
+| 10 | `--skip-compress` | Low | Medium — performance tuning |
+
+---
+
+## FastSync-Specific Features (Not in rsync)
+
+| Feature | Description |
+|---------|-------------|
+| `-m` | Multithreaded pipeline (scanner/loader/sender) |
+| `-s` | Chunk serialization mode |
+| `-f` / `--sendfile` | Zero-copy sendfile() syscall (TCP only) |
+| `-c [level]` | zstd compression level (1-22) |
+| `--chunk-size` | Configurable chunk size |
+| `--queue-size` | Pipeline queue capacity |
+| `--tls` | TLS encryption (mutual auth) |
+| `--fastsync-server-path` | Path to fastsync-server binary |
+| `--server-host` / `--server-port` | Direct TCP connection |
+| Incremental sync | Skip unchanged files (size+mtime) |
+| Delta transfer | Block-level delta for changed files |

src/client/client_cli.c

@@ -402,6 +402,72 @@ static int parse_args(Config* config, int argc, char* argv[], int* positional_ar
         return -1;
       free(config->link_dest);
       config->link_dest = dup;
+    } else if (strcmp(argv[i], "--partial-dir") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --partial-dir\n");
+        return -1;
+      }
+      free(config->partial_dir);
+      config->partial_dir = dup;
+    } else if (strcmp(argv[i], "--suffix") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup) {
+        fprintf(stderr, "Error: memory allocation failed for --suffix\n");
+        return -1;
+      }
+      free(config->suffix);
+      config->suffix = dup;
+    } else if (strcmp(argv[i], "--delete-before") == 0) {
+      config->delete_before = true;
+    } else if (strcmp(argv[i], "-T") == 0 && i + 1 < argc) {
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: -T must be a positive integer\n");
+        return -1;
+      }
+      config->timeout = val;
+    } else if (strcmp(argv[i], "--address") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->address);
+      config->address = dup;
+    } else if (strcmp(argv[i], "--bind-address") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->bind_address);
+      config->bind_address = dup;
+    } else if (strcmp(argv[i], "--ipv6") == 0) {
+      config->ipv6 = true;
+    } else if (strcmp(argv[i], "--ipv4") == 0) {
+      config->ipv4 = true;
+    } else if (strcmp(argv[i], "--daemon") == 0) {
+      config->daemon = true;
+    } else if (strcmp(argv[i], "--config") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->daemon_config);
+      config->daemon_config = dup;
+    } else if (strcmp(argv[i], "--server") == 0) {
+      config->server_mode = true;
+    } else if (strcmp(argv[i], "--checksum") == 0) {
+      config->checksum = true;
+    } else if (strcmp(argv[i], "--compress-choice") == 0 && i + 1 < argc) {
+      char* dup = str_dup(argv[++i]);
+      if (!dup)
+        return -1;
+      free(config->compress_choice);
+      config->compress_choice = dup;
+    } else if (strcmp(argv[i], "--compress-level") == 0 && i + 1 < argc) {
+      int val;
+      if (!parse_positive_int(argv[++i], &val)) {
+        fprintf(stderr, "Error: --compress-level must be a positive integer\n");
+        return -1;
+      }
+      config->compression_level = val;
     } else if (argv[i][0] == '-') {
       fprintf(stderr, "Unknown option: %s\n", argv[i]);
       print_usage();
@@ -507,16 +573,23 @@ static void print_usage(void) {
   printf("  --key <path>        TLS private key file (PEM)\n");
   printf("  --ca <path>         TLS CA certificate file (PEM)\n");
   printf("  --timeout <sec>     I/O timeout in seconds (default: 30)\n");
+  printf("  -T <sec>            Alias for --timeout\n");
   printf("  --contimeout <sec>  Connection timeout in seconds (default: 10)\n");
+  printf("  --address <host>    Server hostname/IP to connect to\n");
+  printf("  --bind-address <ip> Bind to specific local address\n");
+  printf("  --ipv6              Prefer IPv6 connections\n");
+  printf("  --ipv4              Prefer IPv4 connections\n");
   printf("  -q, --quiet         Suppress non-error output\n");
   printf("  --silent            Alias for --quiet\n");
   printf("  --backup            Backup existing files before overwriting\n");
   printf("  --backup-dir <dir>  Directory for backups (requires --backup)\n");
+  printf("  --suffix <str>      Backup suffix (default: ~)\n");
   printf("  --stats             Print transfer statistics at end\n");
   printf("  --max-depth <n>     Maximum directory depth (0=unlimited)\n");
   printf("  --log-file <path>   Write log messages to file\n");
   printf("  --queue-size <n>    Queue capacity for multithreaded mode (default: 100)\n");
   printf("  --partial           Keep partial files on interrupted transfer\n");
+  printf("  --partial-dir <dir> Directory for partial files\n");
   printf("  --fastsync-server-path <path>\n");
   printf("                      Path to fastsync-server on remote (default: fastsync-server)\n");
   printf("  -l, --links         Copy symlinks as symlinks\n");
@@ -538,6 +611,7 @@ static void print_usage(void) {
   printf("  --inplace           Update files in-place (no temp+rename)\n");
   printf("  --append            Append data to shorter files\n");
   printf("  --append-verify     Append with verify\n");
+  printf("  --delete-before     Delete before transfer\n");
   printf("  --delete-excluded   Also delete excluded files\n");
   printf("  --delete-after      Delete after transfer, not before\n");
   printf("  --max-delete <n>    Maximum number of files to delete\n");
@@ -548,6 +622,12 @@ static void print_usage(void) {
   printf("  -R, --relative      Use relative paths\n");
   printf("  -e, --rsh <cmd>     Specify remote shell\n");
   printf("  --rsync-path <path> Path to remote binary\n");
+  printf("  --daemon            Run in daemon mode\n");
+  printf("  --config <path>     Path to configuration file\n");
+  printf("  --server            Run in server mode\n");
+  printf("  --checksum          Skip files based on checksum, not mod-time/size\n");
+  printf("  --compress-choice <alg>  Compression algorithm (default: zstd)\n");
+  printf("  --compress-level <n>    Compression level (default: 5)\n");
   printf("  --temp-dir <dir>    Temporary directory for files\n");
   printf("  --compare-dest <dir>  Compare destination\n");
   printf("  --copy-dest <dir>   Copy destination\n");

src/client/client_send.c

@@ -34,7 +34,7 @@ static int send_dry_run_manifest(Config* config) {
       config->send_directory, config->use_metadata, config->chunk_size, config->exclude_patterns,
       config->exclude_count, config->include_patterns, config->include_count, config->max_size,
       config->min_size, config->max_depth, config->follow_symlinks, config->copy_links,
-      config->safe_links, config->copy_unsafe_links, false);
+      config->safe_links, config->copy_unsafe_links, config->checksum);
   if (!scanner)
     return -1;
   Chunk* chunk;
@@ -374,7 +374,8 @@ static int scan_directory_multithreaded(void* pipeline_context) {
       context->config->exclude_patterns, context->config->exclude_count,
       context->config->include_patterns, context->config->include_count, context->config->max_size,
       context->config->min_size, context->config->max_depth, 4, context->config->follow_symlinks,
-      context->config->copy_links, context->config->safe_links, context->config->copy_unsafe_links, false);
+      context->config->copy_links, context->config->safe_links, context->config->copy_unsafe_links,
+      context->config->checksum);
 
   Chunk* current_chunk;
   while ((current_chunk = parallel_scanner_next(scanner)) != NULL) {
@@ -509,9 +510,10 @@ int send_files(Config* config) {
       config->send_directory, config->use_metadata, config->chunk_size, config->exclude_patterns,
       config->exclude_count, config->include_patterns, config->include_count, config->max_size,
       config->min_size, config->max_depth, config->follow_symlinks, config->copy_links,
-      config->safe_links, config->copy_unsafe_links, false);
+      config->safe_links, config->copy_unsafe_links, config->checksum);
   Chunk* current_chunk;
   unsigned long long total_bytes = 0;
+  int total_files = 0;
   time_t last_progress = 0;
   time_t start = time(NULL);
   ArrayList* manifest = config->use_delete ? array_list_create(free) : NULL;
@@ -519,6 +521,7 @@ int send_files(Config* config) {
     unsigned long long chunk_bytes = 0;
     for (int i = 0; i < current_chunk->element_count; i++) {
       chunk_bytes += current_chunk->items[i]->data->size;
+      total_files++;
       if (manifest) {
         const char* p = current_chunk->items[i]->path;
         if (*p == '/')
@@ -566,11 +569,16 @@ int send_files(Config* config) {
     goto send_fail;
   Status s;
   int ok = receive_status(client->file_descriptor, &s) && s == STATUS_OK;
+  double elapsed_total = difftime(time(NULL), start);
   if (config->show_progress) {
-    double elapsed = difftime(time(NULL), start);
+    double rate = elapsed_total > 0 ? total_bytes / (1048576.0 * elapsed_total) : 0;
-    double rate = elapsed > 0 ? total_bytes / (1048576.0 * elapsed) : 0;
     fprintf(stderr, "\rSent %.1f MB  (%.1f MB/s)  Done.\n", total_bytes / 1048576.0, rate);
   }
+  if (config->stats) {
+    double rate = elapsed_total > 0 ? total_bytes / (1048576.0 * elapsed_total) : 0;
+    fprintf(stderr, "Stats: %d files, %.1f MB, %.1f MB/s\n", total_files, total_bytes / 1048576.0,
+            rate);
+  }
   directory_scanner_destroy(scanner);
   client_disconnect(client);
   client_delete(client);

src/client/scanner.c

@@ -347,11 +347,62 @@ ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata
     char* cur_path = path_cat(root_directory, entry->d_name);
     if (!cur_path)
       continue;
+    struct stat lstats;
+    if (lstat(cur_path, &lstats) != 0) {
+      free(cur_path);
+      continue;
+    }
+    bool is_symlink = S_ISLNK(lstats.st_mode);
+
+    // Skip symlinks unless the user explicitly enabled following/copying them.
+    if (is_symlink && !follow_symlinks && !copy_links && !safe_links && !copy_unsafe_links) {
+      free(cur_path);
+      continue;
+    }
+
+    // --safe-links: reject symlinks pointing outside the source tree.
+    if (is_symlink && safe_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = 0;
+      if (link_target[0] == '/') {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    // --copy-unsafe-links (without --copy-links): only copy absolute symlinks.
+    if (is_symlink && copy_unsafe_links && !copy_links) {
+      char link_target[4096];
+      ssize_t len = readlink(cur_path, link_target, sizeof(link_target) - 1);
+      if (len < 0) {
+        free(cur_path);
+        continue;
+      }
+      link_target[len] = 0;
+      bool unsafe = (link_target[0] == '/');
+      if (!unsafe) {
+        free(cur_path);
+        continue;
+      }
+    }
+
+    // Determine whether to use lstat or stat results for the entry.
     struct stat st;
+    bool use_lstat_res = is_symlink && follow_symlinks && !copy_links;
+    if (use_lstat_res) {
+      st = lstats;
+    } else {
       if (stat(cur_path, &st) != 0) {
         free(cur_path);
         continue;
       }
+    }
+
     if (S_ISDIR(st.st_mode)) {
       array_list_add(subdirs, cur_path);
     } else {

src/shared/chunk.c

@@ -12,6 +12,9 @@
 #include "metadata.h"
 #include "protocol.h"
 
+/* Maximum individual file data size within a chunk (64 MB) */
+#define MAX_FILE_DATA_SIZE (64ULL * 1024 * 1024)
+
 Chunk* chunk_create(File** items, int element_count) {
   Chunk* chunk = (Chunk*)malloc(sizeof(Chunk));
   if (chunk == NULL) {
@@ -157,6 +160,14 @@ Chunk* chunk_deserialize(Data* data, bool use_metadata) {
       return NULL;
     }
 
+    // Reject individual file data larger than the maximum allowed size.
+    if (file_data_size > MAX_FILE_DATA_SIZE) {
+      log_message(LOG_LEVEL_ERROR, "File data size %zu exceeds maximum %llu", file_data_size,
+                  (unsigned long long)MAX_FILE_DATA_SIZE);
+      array_list_delete(files);
+      return NULL;
+    }
+
     void* file_data = malloc(file_data_size);
     if (file_data == NULL) {
       perror("Could not allocate memory for file data");
@@ -210,6 +221,15 @@ Chunk* receive_chunk_data(int fd, const Config* config) {
       return NULL;
     }
   }
+
+  // Reject chunks larger than the maximum allowed size to prevent OOM.
+  if (data_to_process->size > MAX_CHUNK_SIZE) {
+    log_message(LOG_LEVEL_ERROR, "Chunk size %zu exceeds maximum %llu", data_to_process->size,
+                (unsigned long long)MAX_CHUNK_SIZE);
+    data_destroy(data_to_process);
+    return NULL;
+  }
+
   Chunk* chunk = chunk_deserialize(data_to_process, config->use_metadata);
   data_destroy(data_to_process);
   if (chunk == NULL)

src/shared/config.c

@@ -152,9 +152,6 @@ void config_delete(Config* config) {
   free(config->rsh_command);
   free(config->rsync_path);
   free(config->temp_dir);
-  free(config->partial_dir);
-  free(config->suffix);
-  free(config->compress_choice);
   free(config->compare_dest);
   free(config->copy_dest);
   free(config->link_dest);
@@ -245,7 +242,6 @@ bool config_send(int file_descriptor, const Config* config) {
     return false;
   if (!send_str(file_descriptor, config->temp_dir ? config->temp_dir : ""))
     return false;
-  Status status;
   if (!send_int(file_descriptor, config->partial))
     return false;
   if (!send_str(file_descriptor, config->partial_dir ? config->partial_dir : ""))
@@ -258,6 +254,7 @@ bool config_send(int file_descriptor, const Config* config) {
     return false;
   if (!send_str(file_descriptor, config->compress_choice ? config->compress_choice : ""))
     return false;
+  Status status;
   if (!receive_status(file_descriptor, &status))
     return false;
   if (status != STATUS_OK) {
@@ -392,18 +389,6 @@ Config* config_receive(int file_descriptor) {
   config->compare_dest = NULL;
   config->copy_dest = NULL;
   config->link_dest = NULL;
-  config->partial_dir = NULL;
-  config->suffix = NULL;
-  config->delete_before = false;
-  config->address = NULL;
-  config->bind_address = NULL;
-  config->ipv6 = false;
-  config->ipv4 = false;
-  config->daemon = false;
-  config->daemon_config = NULL;
-  config->server_mode = false;
-  config->checksum = false;
-  config->compress_choice = NULL;
   if (!receive_int(file_descriptor, &tmp))
     goto error;
   config->backup = tmp;
@@ -466,6 +451,31 @@ Config* config_receive(int file_descriptor) {
   config->temp_dir = receive_str(file_descriptor);
   if (config->temp_dir == NULL)
     goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->partial = tmp;
+  config->partial_dir = receive_str(file_descriptor);
+  if (config->partial_dir == NULL)
+    goto error;
+  config->suffix = receive_str(file_descriptor);
+  if (config->suffix == NULL)
+    goto error;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->delete_before = tmp;
+  if (!receive_int(file_descriptor, &tmp))
+    goto error;
+  config->checksum = tmp;
+  config->compress_choice = receive_str(file_descriptor);
+  if (config->compress_choice == NULL)
+    goto error;
+  config->address = NULL;
+  config->bind_address = NULL;
+  config->ipv6 = false;
+  config->ipv4 = false;
+  config->daemon = false;
+  config->daemon_config = NULL;
+  config->server_mode = false;
   config->server_host = str_dup("127.0.0.1");
   config->server_port = 8080;
   if (!send_status(file_descriptor, STATUS_OK))

src/shared/file.c

@@ -35,7 +35,8 @@ File* file_create(const char* path) {
     return NULL;
   }
 
-  strcpy(file->path, path);
+  memcpy(file->path, path, path_len);
+  file->path[path_len] = '\0';
   file->data = data_create_reserve(0);
   if (file->data == NULL) {
     free(file->path);
@@ -142,7 +143,8 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
   }
 
   char* resolved_root = NULL;
-  const char* actual_root = (partial_dir && config && config->partial) ? partial_dir : root_directory;
+  const char* actual_root =
+      (partial_dir && config && config->partial) ? partial_dir : root_directory;
   resolved_root = realpath(actual_root, NULL);
   if (resolved_root == NULL) {
     if (mkdir_r(actual_root)) {
@@ -187,7 +189,7 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
       if (backup_path) {
         char* backup_dir_path = str_dup(backup_path);
         if (backup_dir_path) {
-          char* bdir = dirname(backup_dir_path);
+          const char* bdir = dirname(backup_dir_path);
           mkdir_r(bdir);
           free(backup_dir_path);
         }
@@ -222,8 +224,7 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
   size_t root_len = strlen(resolved_root);
   if (strncmp(resolved_dir, resolved_root, root_len) != 0 ||
       (resolved_dir[root_len] != '\0' && resolved_dir[root_len] != '/')) {
-    log_message(LOG_LEVEL_ERROR, "Path escape detected: %s is outside %s", disk_path,
+    log_message(LOG_LEVEL_ERROR, "Path escape detected: %s is outside %s", disk_path, actual_root);
-                actual_root);
     free(resolved_dir);
     free(resolved_root);
     free(disk_path);
@@ -517,8 +518,8 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
   return file;
 }
 
-bool to_disk(const char* path, const void* data, unsigned long long data_size,
+bool to_disk(const char* path, const void* data, unsigned long long data_size, bool inplace,
-             bool inplace, bool sparse) {
+             bool sparse) {
   char* tmp_path = NULL;
   char* directory = NULL;
 

src/shared/file.h

@@ -34,8 +34,8 @@ bool file_send_sendfile(File* file, int file_descriptor, bool use_metadata, int
 size_t file_content_to_buffer(File* file);
 FileMetadata* file_metadata_create(const struct stat* stats);
 void file_metadata_destroy(void* metadata);
-bool to_disk(const char* path, const void* data, unsigned long long data_size,
+bool to_disk(const char* path, const void* data, unsigned long long data_size, bool inplace,
-             bool inplace, bool sparse);
+             bool sparse);
 bool file_save_to_disk(const char* root_directory, File* file, const Config* config);
 File* receive_incremental_check(int fd, const Config* config, bool* skipped);
 int receive_manifest(int fd, const Config* config, int* next_status);

src/shared/protocol.h

@@ -11,6 +11,9 @@
 /* Maximum allowed data payload size for receive_data (100 MB) */
 #define MAX_DATA_PAYLOAD_SIZE (100ULL * 1024 * 1024)
 
+/* Maximum chunk size (64 MB) — prevents unbounded allocation from the wire */
+#define MAX_CHUNK_SIZE (64ULL * 1024 * 1024)
+
 typedef struct ssl_st SSL;
 
 typedef int Status;

src/shared/utils.c

@@ -13,7 +13,7 @@ bool mkdir_r(const char* path) {
   char* path_duplicate = malloc(strlen(path) + 1);
   if (!path_duplicate)
     return false;
-  strcpy(path_duplicate, path);
+  memcpy(path_duplicate, path, strlen(path) + 1);
   char* path_current = (char*)malloc((strlen(path) + 2) * sizeof(char));
   if (!path_current) {
     free(path_duplicate);
@@ -21,7 +21,8 @@ bool mkdir_r(const char* path) {
   }
   char* path_current_position = path_current;
   if (path[0] == '/') {
-    strcpy(path_current, "/");
+    path_current[0] = '/';
+    path_current[1] = '\0';
     path_current_position += 1;
   } else {
     path_current[0] = '\0';
@@ -31,10 +32,12 @@ bool mkdir_r(const char* path) {
   const char* part = strtok_r(path_duplicate, delimiter, &saveptr);
   bool ok = true;
   while (part != NULL) {
-    strcpy(path_current_position, part);
+    size_t part_len = strlen(part);
-    path_current_position += strlen(part) * sizeof(char);
+    memcpy(path_current_position, part, part_len);
-    strcpy(path_current_position, "/");
+    path_current_position += part_len;
-    path_current_position += sizeof(char);
+    path_current_position[0] = '/';
+    path_current_position[1] = '\0';
+    path_current_position++;
     struct stat st;
     if (stat(path_current, &st) != 0) {
       if (mkdir(path_current, 0755) != 0) {
@@ -53,8 +56,11 @@ bool mkdir_r(const char* path) {
 char* str_dup(const char* string) {
   if (string == NULL)
     return NULL;
-  char* new_string = (char*)malloc(strlen(string) + 1);
+  size_t str_len = strlen(string);
-  strcpy(new_string, string);
+  char* new_string = (char*)malloc(str_len + 1);
+  if (new_string == NULL)
+    return NULL;
+  memcpy(new_string, string, str_len + 1);
   return new_string;
 }
 

tests/test_chunk.c

@@ -11,7 +11,7 @@ static void test_file_operations() {
   char* test_content = "Hello, Chunk System!";
   unsigned long long test_len = strlen(test_content);
 
-  to_disk(test_path, test_content, test_len);
+  to_disk(test_path, test_content, test_len, false, false);
 
   File* f = file_create(test_path);
   EXPECT_NOT_NULL(f);
@@ -43,8 +43,8 @@ static void test_chunk_operations() {
   char* content2 = "chunk item number 2";
   unsigned long long len2 = strlen(content2);
 
-  to_disk(path1, content1, len1);
+  to_disk(path1, content1, len1, false, false);
-  to_disk(path2, content2, len2);
+  to_disk(path2, content2, len2, false, false);
 
   struct stat st1, st2;
   stat(path1, &st1);

tests/test_compression.c

@@ -62,8 +62,8 @@ static void test_chunk_compress_decompress_roundtrip() {
   char* content2 = "chunk compression test file 2 with more data";
   unsigned long long len2 = strlen(content2);
 
-  to_disk(path1, content1, len1);
+  to_disk(path1, content1, len1, false, false);
-  to_disk(path2, content2, len2);
+  to_disk(path2, content2, len2, false, false);
 
   struct stat st1, st2;
   EXPECT_EQ_INT(stat(path1, &st1), 0);

tests/test_file.c

@@ -34,7 +34,7 @@ static void test_file_destroy_normal() {
 
 static void test_file_load_data() {
   const char* content = "Hello Load Test";
-  EXPECT_TRUE(to_disk("test_file_load_data.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_file_load_data.txt", content, strlen(content), false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_file_load_data.txt", &st), 0);
@@ -89,7 +89,7 @@ static void test_file_save_to_disk() {
 
 static void test_to_disk_basic() {
   const char* content = "Basic to_disk test";
-  EXPECT_TRUE(to_disk("test_to_disk_basic.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_to_disk_basic.txt", content, strlen(content), false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_to_disk_basic.txt", &st), 0);
@@ -108,7 +108,7 @@ static void test_to_disk_basic() {
 
 static void test_to_disk_creates_dirs() {
   const char* content = "Nested dir test";
-  EXPECT_TRUE(to_disk("test_nested_tmp/nested/file.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_nested_tmp/nested/file.txt", content, strlen(content), false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_nested_tmp/nested/file.txt", &st), 0);
@@ -128,7 +128,7 @@ static void test_to_disk_creates_dirs() {
 
 static void test_file_content_to_buffer() {
   const char* content = "Buffer content test";
-  EXPECT_TRUE(to_disk("test_buffer_file.txt", content, strlen(content)));
+  EXPECT_TRUE(to_disk("test_buffer_file.txt", content, strlen(content), false, false));
 
   File* f = file_create("test_buffer_file.txt");
   EXPECT_NOT_NULL(f);
@@ -250,7 +250,7 @@ static void test_file_send_no_path() {
 }
 
 static void test_file_metadata_create() {
-  EXPECT_TRUE(to_disk("test_meta_file.txt", "metadata test", 13));
+  EXPECT_TRUE(to_disk("test_meta_file.txt", "metadata test", 13, false, false));
   struct stat st;
   EXPECT_EQ_INT(stat("test_meta_file.txt", &st), 0);
 
@@ -359,7 +359,7 @@ static void test_file_send_single_calls_metadata_and_path() {
   /* Create a real file on disk so we can have metadata */
   const char* content = "File with metadata";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_meta_send.txt", content, len));
+  EXPECT_TRUE(to_disk("test_meta_send.txt", content, len, false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_meta_send.txt", &st), 0);

tests/test_file_sendfile.c

@@ -15,7 +15,7 @@
 static void test_sendfile_basic() {
   const char* content = "Hello from sendfile test!";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_sendfile_basic.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_basic.txt", content, len, false, false));
 
   File* file = file_create("test_sendfile_basic.txt");
   EXPECT_NOT_NULL(file);
@@ -77,7 +77,7 @@ static void test_sendfile_basic() {
 static void test_sendfile_empty_file() {
   const char* content = "";
   size_t len = 0;
-  EXPECT_TRUE(to_disk("test_sendfile_empty.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_empty.txt", content, len, false, false));
 
   File* file = file_create("test_sendfile_empty.txt");
   EXPECT_NOT_NULL(file);
@@ -156,7 +156,7 @@ static void test_sendfile_missing_file() {
 static void test_sendfile_compression_fallback() {
   const char* content = "Compression fallback content";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_sendfile_comp.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_comp.txt", content, len, false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("test_sendfile_comp.txt", &st), 0);
@@ -222,7 +222,7 @@ static void test_sendfile_compression_fallback() {
 static void test_sendfile_no_path() {
   const char* content = "No path sendfile test";
   size_t len = strlen(content);
-  EXPECT_TRUE(to_disk("test_sendfile_nopath.txt", content, len));
+  EXPECT_TRUE(to_disk("test_sendfile_nopath.txt", content, len, false, false));
 
   File* file = file_create("test_sendfile_nopath.txt");
   EXPECT_NOT_NULL(file);

tests/test_fuzz_smoke.c

@@ -101,7 +101,7 @@ static void test_fuzz_delta_deserialize() {
 /* Smoke test for metadata_from_buf fuzz target */
 static void test_fuzz_metadata_from_buf() {
   /* Create a real file to get metadata from */
-  EXPECT_TRUE(to_disk("fuzz_meta_test.txt", "metadata test", 13));
+  EXPECT_TRUE(to_disk("fuzz_meta_test.txt", "metadata test", 13, false, false));
 
   struct stat st;
   EXPECT_EQ_INT(stat("fuzz_meta_test.txt", &st), 0);

tests/test_metadata.c

@@ -112,7 +112,7 @@ static void test_metadata_send_null() {
 static void test_file_restore_metadata() {
   const char* path = "temp_meta_restore_test.txt";
   const char* content = "test content";
-  EXPECT_TRUE(to_disk(path, content, strlen(content)));
+  EXPECT_TRUE(to_disk(path, content, strlen(content), false, false));
 
   FileMetadata m;
   m.mode = 0644;

tests/test_property.c

@@ -84,7 +84,7 @@ static void test_property_chunk_roundtrip() {
     for (int i = 0; i < content_len; i++)
       content[i] = (char)(rand() % 256);
 
-    to_disk(path, content, content_len);
+    to_disk(path, content, content_len, false, false);
 
     struct stat st;
     stat(path, &st);

tests/test_robustness.c

@@ -13,7 +13,7 @@
 static void test_chunk_deserialize_truncated() {
   char* path = "test_rob_trunc.txt";
   char* content = "hello";
-  to_disk(path, content, strlen(content));
+  to_disk(path, content, strlen(content), false, false);
 
   struct stat st;
   stat(path, &st);

tests/test_scanner.c

@@ -7,7 +7,7 @@
 #include <unistd.h>
 
 static void create_test_file(const char* path, const char* content) {
-  (void)to_disk(path, content, strlen(content));
+  (void)to_disk(path, content, strlen(content), false, false);
 }
 
 static void test_scanner_single_file() {