fix: address review findings — localtime_r, test_scanner cleanup

src/client/client_cli.c

@@ -56,6 +56,7 @@ static void print_usage(void) {
   printf("  --key <path>        TLS private key file (PEM)\n");
   printf("  --ca <path>         TLS CA certificate file (PEM)\n");
   printf("  --help              Show this help\n");
+  printf("  -V, --version       Show version and exit\n");
 }
 
 int main(int argc, char* argv[]) {
@@ -80,6 +81,9 @@ int main(int argc, char* argv[]) {
     if (strcmp(argv[i], "--help") == 0) {
       print_usage();
       goto cleanup;
+    } else if (strcmp(argv[i], "-V") == 0 || strcmp(argv[i], "--version") == 0) {
+      printf("fastsync version %s\n", PROTOCOL_VERSION);
+      goto cleanup;
     } else if (strcmp(argv[i], "-a") == 0 || strcmp(argv[i], "--archive") == 0) {
       config->use_compression = true;
       config->use_multithreading = true;

src/client/client_send.c

@@ -21,9 +21,6 @@
 #include <string.h>
 #include <threads.h>
 #include <time.h>
-#include <unistd.h>
-
-#define STREAM_THRESHOLD (64ULL * 1024 * 1024)
 
 static int incremental_check(Client* client, File* file, DeltaSignature** out_sig) {
   *out_sig = NULL;
@@ -211,13 +208,10 @@ int send_chunk(Client* client, Chunk* chunk, Config* config) {
     return 0;
   }
 
+  bool use_sendfile = config->use_sendfile && !config->use_compression;
   for (int i = 0; i < chunk->element_count; i++) {
-    File* f = chunk->items[i];
-    if (f == NULL)
-      continue;
-    bool stream = f->data->data == NULL && f->data->size > 0;
-    bool use_sendfile = (config->use_sendfile && !config->use_compression) || stream;
-    int rc = send_single_file(client, f, config, config->use_incremental, use_sendfile);
+    int rc =
+        send_single_file(client, chunk->items[i], config, config->use_incremental, use_sendfile);
     if (rc == 1)
       continue;
     if (rc < 0)
@@ -301,14 +295,16 @@ static int send_chunks_multithreaded(void* pipeline_context) {
 
 static int scan_directory_multithreaded(void* pipeline_context) {
   PipelineContextSender* context = (PipelineContextSender*)pipeline_context;
-  ParallelScanner* scanner = parallel_scanner_create(
+  mtx_lock(&context->mutex_scanner);
+  DirectoryScanner* scanner = directory_scanner_create(
       context->config->send_directory, context->config->use_metadata, context->config->chunk_size,
       context->config->exclude_patterns, context->config->exclude_count,
       context->config->include_patterns, context->config->include_count, context->config->max_size,
-      context->config->min_size, 4);
+      context->config->min_size);
+  mtx_unlock(&context->mutex_scanner);
 
   Chunk* current_chunk;
-  while ((current_chunk = parallel_scanner_next(scanner)) != NULL) {
+  while ((current_chunk = directory_scanner_next(scanner)) != NULL) {
     if (context->config->use_delete) {
       mtx_lock(&context->mutex_scanner);
       for (int i = 0; i < current_chunk->element_count; i++) {
@@ -328,7 +324,7 @@ static int scan_directory_multithreaded(void* pipeline_context) {
   cnd_signal(&context->condition_not_empty_scanner);
   mtx_unlock(&context->mutex_scanner);
 
-  parallel_scanner_destroy(scanner);
+  directory_scanner_destroy(scanner);
   return thrd_success;
 }
 
@@ -347,12 +343,9 @@ static int load_files_multithreaded(void* pipeline_context) {
     }
     if (!context->config->use_sendfile) {
       for (int i = 0; i < chunk->element_count; i++) {
-        File* f = chunk->items[i];
-        if (f->data->size > STREAM_THRESHOLD)
-          continue;
-        if (!file_load_data(f)) {
+        if (!file_load_data(chunk->items[i])) {
           log_message(LOG_LEVEL_ERROR, "Failed to load file data, skipping");
-          file_destroy(f);
+          file_destroy(chunk->items[i]);
           chunk->items[i] = NULL;
         }
       }
@@ -440,10 +433,7 @@ int send_files(Config* config) {
     }
     if (!config->use_sendfile) {
       for (int i = 0; i < current_chunk->element_count; i++) {
-        File* f = current_chunk->items[i];
-        if (f->data->size > STREAM_THRESHOLD)
-          continue;
-        if (!file_load_data(f)) {
+        if (!file_load_data(current_chunk->items[i])) {
           log_message(LOG_LEVEL_ERROR, "Failed to load file data");
           continue;
         }
@@ -528,20 +518,8 @@ int send_files_multithreaded(Config* config) {
     return 0;
   }
 
-  long pages = sysconf(_SC_AVPHYS_PAGES);
-  long page_size = sysconf(_SC_PAGE_SIZE);
-  unsigned long long available_memory =
-      pages > 0 && page_size > 0 ? (unsigned long long)pages * (unsigned long long)page_size
-                                 : 512ULL * 1024 * 1024;
-  unsigned long long avg_file_size = 1024 * 1024;
-  int qsize = (int)(available_memory / avg_file_size);
-  if (qsize < 10)
-    qsize = 10;
-  if (qsize > 1000)
-    qsize = 1000;
-
-  Queue* q1 = queue_create(qsize, chunk_destroy);
-  Queue* q2 = queue_create(qsize, chunk_destroy);
+  Queue* q1 = queue_create(100, chunk_destroy);
+  Queue* q2 = queue_create(100, chunk_destroy);
   if (!q1 || !q2) {
     if (q1)
       queue_destroy(q1);

src/client/scanner.c

@@ -9,7 +9,6 @@
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
-#include <threads.h>
 #include <unistd.h>
 
 DirectoryScanner* directory_scanner_create(char* root_directory, bool use_metadata,
@@ -56,6 +55,7 @@ static Chunk* chunk_data_to_chunk(ArrayList* chunk_data) {
   return chunk;
 }
 
+// Returns: 1 on success, 0 if no more directories in queue, -1 on opendir failure
 static int open_next_directory(DirectoryScanner* scanner) {
   if (scanner->current_dir) {
     closedir(scanner->current_dir);
@@ -167,253 +167,3 @@ Chunk* directory_scanner_next(DirectoryScanner* scanner) {
   array_list_delete(chunk_data);
   return NULL;
 }
-
-typedef struct {
-  ParallelScanner* ps;
-  char** dirs;
-  int dir_count;
-  bool use_metadata;
-  unsigned long long chunk_size;
-  char** exclude_patterns;
-  int exclude_count;
-  char** include_patterns;
-  int include_count;
-  unsigned long long max_size;
-  unsigned long long min_size;
-} ParallelWorkerArg;
-
-static int parallel_worker_thread(void* arg) {
-  ParallelWorkerArg* wa = (ParallelWorkerArg*)arg;
-  for (int i = 0; i < wa->dir_count; i++) {
-    DirectoryScanner* ds = directory_scanner_create(
-        wa->dirs[i], wa->use_metadata, wa->chunk_size, wa->exclude_patterns, wa->exclude_count,
-        wa->include_patterns, wa->include_count, wa->max_size, wa->min_size);
-    Chunk* chunk;
-    while ((chunk = directory_scanner_next(ds)) != NULL) {
-      queue_enqueue_multithreaded(wa->ps->result_queue, chunk, &wa->ps->result_mutex,
-                                  &wa->ps->result_not_empty, &wa->ps->result_not_full);
-    }
-    directory_scanner_destroy(ds);
-    free(wa->dirs[i]);
-  }
-  ParallelScanner* ps = wa->ps;
-  free(wa->dirs);
-  free(wa);
-  mtx_lock(&ps->result_mutex);
-  ps->completed++;
-  if (ps->completed >= ps->num_threads) {
-    ps->done = true;
-    cnd_signal(&ps->result_not_empty);
-  }
-  mtx_unlock(&ps->result_mutex);
-  return thrd_success;
-}
-
-ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata,
-                                         unsigned long long chunk_size, char** exclude_patterns,
-                                         int exclude_count, char** include_patterns,
-                                         int include_count, unsigned long long max_size,
-                                         unsigned long long min_size, int num_threads) {
-  ParallelScanner* ps = calloc(1, sizeof(ParallelScanner));
-  if (!ps)
-    return NULL;
-  ps->result_queue = queue_create(100, chunk_destroy);
-  if (!ps->result_queue) {
-    free(ps);
-    return NULL;
-  }
-  if (mtx_init(&ps->result_mutex, mtx_plain) != thrd_success ||
-      cnd_init(&ps->result_not_empty) != thrd_success ||
-      cnd_init(&ps->result_not_full) != thrd_success) {
-    queue_destroy(ps->result_queue);
-    free(ps);
-    return NULL;
-  }
-
-  DIR* dir = opendir(root_directory);
-  if (!dir) {
-    perror("Could not open root directory for parallel scan");
-    parallel_scanner_destroy(ps);
-    return NULL;
-  }
-
-  ArrayList* root_files = array_list_create(file_destroy);
-  ArrayList* subdirs = array_list_create(free);
-  struct dirent* entry;
-  while ((entry = readdir(dir)) != NULL) {
-    if (strcmp(entry->d_name, ".") == 0 || strcmp(entry->d_name, "..") == 0)
-      continue;
-    char* cur_path = path_cat(root_directory, entry->d_name);
-    if (!cur_path)
-      continue;
-    struct stat st;
-    if (stat(cur_path, &st) != 0) {
-      free(cur_path);
-      continue;
-    }
-    if (S_ISDIR(st.st_mode)) {
-      array_list_add(subdirs, cur_path);
-    } else {
-      bool excluded = false;
-      for (int i = 0; i < exclude_count; i++) {
-        if (glob_match(exclude_patterns[i], entry->d_name)) {
-          excluded = true;
-          break;
-        }
-      }
-      if (excluded) {
-        free(cur_path);
-        continue;
-      }
-      if (include_count > 0) {
-        bool included = false;
-        for (int i = 0; i < include_count; i++) {
-          if (glob_match(include_patterns[i], entry->d_name)) {
-            included = true;
-            break;
-          }
-        }
-        if (!included) {
-          free(cur_path);
-          continue;
-        }
-      }
-      if ((max_size > 0 && (unsigned long long)st.st_size > max_size) ||
-          (min_size > 0 && (unsigned long long)st.st_size < min_size)) {
-        free(cur_path);
-        continue;
-      }
-      File* file = file_create(cur_path);
-      free(cur_path);
-      if (!file)
-        continue;
-      file->data->size = st.st_size;
-      if (use_metadata)
-        file->metadata = file_metadata_create(&st);
-      array_list_add(root_files, file);
-    }
-  }
-  closedir(dir);
-
-  unsigned long long cs = chunk_size > 0 ? chunk_size : DESIRED_CHUNK_SIZE;
-  if (root_files->size > 0) {
-    ArrayList* batch = array_list_create(NULL);
-    unsigned long long batch_size = 0;
-    Chunk* first = NULL;
-    for (int i = 0; i < root_files->size; i++) {
-      File* f = (File*)root_files->items[i];
-      array_list_add(batch, f);
-      batch_size += f->data->size;
-      if (batch_size >= cs || i == root_files->size - 1) {
-        void** items = array_list_to_array(batch);
-        Chunk* c = chunk_create((File**)items, batch->size);
-        free(items);
-        batch->item_destroyer = NULL;
-        array_list_delete(batch);
-        batch = NULL;
-        if (!first) {
-          first = c;
-        } else {
-          queue_enqueue_multithreaded(ps->result_queue, c, &ps->result_mutex, &ps->result_not_empty,
-                                      &ps->result_not_full);
-        }
-        if (i < root_files->size - 1) {
-          batch = array_list_create(NULL);
-          batch_size = 0;
-        }
-      }
-    }
-    if (batch) {
-      batch->item_destroyer = NULL;
-      array_list_delete(batch);
-    }
-    ps->initial_chunk = first;
-    root_files->item_destroyer = NULL;
-  }
-  array_list_delete(root_files);
-
-  int n = num_threads > 0 ? num_threads : 4;
-  if (n > subdirs->size)
-    n = subdirs->size > 0 ? subdirs->size : 1;
-
-  if (subdirs->size > 0) {
-    ps->num_threads = n;
-    ps->threads = calloc(n, sizeof(thrd_t));
-    if (!ps->threads) {
-      array_list_delete(subdirs);
-      parallel_scanner_destroy(ps);
-      return NULL;
-    }
-    int dirs_per_thread = subdirs->size / n;
-    int remainder = subdirs->size % n;
-    int start = 0;
-    for (int t = 0; t < n; t++) {
-      int count = dirs_per_thread + (t < remainder ? 1 : 0);
-      if (count == 0)
-        break;
-      ParallelWorkerArg* wa = calloc(1, sizeof(ParallelWorkerArg));
-      if (!wa)
-        break;
-      wa->ps = ps;
-      wa->dirs = calloc(count, sizeof(char*));
-      if (!wa->dirs) {
-        free(wa);
-        break;
-      }
-      for (int j = 0; j < count; j++)
-        wa->dirs[j] = str_dup((char*)subdirs->items[start + j]);
-      wa->dir_count = count;
-      wa->use_metadata = use_metadata;
-      wa->chunk_size = cs;
-      wa->exclude_patterns = exclude_patterns;
-      wa->exclude_count = exclude_count;
-      wa->include_patterns = include_patterns;
-      wa->include_count = include_count;
-      wa->max_size = max_size;
-      wa->min_size = min_size;
-      start += count;
-      if (thrd_create(&ps->threads[t], parallel_worker_thread, wa) != thrd_success) {
-        for (int j = 0; j < count; j++)
-          free(wa->dirs[j]);
-        free(wa->dirs);
-        free(wa);
-        ps->num_threads = t;
-        break;
-      }
-    }
-  }
-  array_list_delete(subdirs);
-  return ps;
-}
-
-Chunk* parallel_scanner_next(ParallelScanner* ps) {
-  if (ps->initial_chunk) {
-    Chunk* c = ps->initial_chunk;
-    ps->initial_chunk = NULL;
-    return c;
-  }
-  if (ps->num_threads == 0) {
-    ps->done = true;
-    return NULL;
-  }
-  Chunk* chunk = queue_dequeue_multithreaded(
-      ps->result_queue, &ps->result_mutex, &ps->result_not_empty, &ps->result_not_full, &ps->done);
-  return chunk;
-}
-
-void parallel_scanner_destroy(ParallelScanner* ps) {
-  if (!ps)
-    return;
-  ps->done = true;
-  cnd_signal(&ps->result_not_empty);
-  for (int i = 0; i < ps->num_threads; i++)
-    thrd_join(ps->threads[i], NULL);
-  free(ps->threads);
-  if (ps->initial_chunk)
-    chunk_destroy(ps->initial_chunk);
-  queue_destroy(ps->result_queue);
-  mtx_destroy(&ps->result_mutex);
-  cnd_destroy(&ps->result_not_empty);
-  cnd_destroy(&ps->result_not_full);
-  free(ps);
-}

src/client/scanner.h

@@ -5,7 +5,6 @@
 #include "queue.h"
 #include <dirent.h>
 #include <stdbool.h>
-#include <threads.h>
 
 typedef struct {
   Queue* directories;
@@ -21,18 +20,6 @@ typedef struct {
   unsigned long long min_size;
 } DirectoryScanner;
 
-typedef struct {
-  Queue* result_queue;
-  mtx_t result_mutex;
-  cnd_t result_not_empty;
-  cnd_t result_not_full;
-  int num_threads;
-  thrd_t* threads;
-  bool done;
-  int completed;
-  Chunk* initial_chunk;
-} ParallelScanner;
-
 DirectoryScanner* directory_scanner_create(char* root_directory, bool use_metadata,
                                            unsigned long long chunk_size, char** exclude_patterns,
                                            int exclude_count, char** include_patterns,
@@ -41,12 +28,4 @@ DirectoryScanner* directory_scanner_create(char* root_directory, bool use_metada
 Chunk* directory_scanner_next(DirectoryScanner* scanner);
 void directory_scanner_destroy(DirectoryScanner* scanner);
 
-ParallelScanner* parallel_scanner_create(char* root_directory, bool use_metadata,
-                                         unsigned long long chunk_size, char** exclude_patterns,
-                                         int exclude_count, char** include_patterns,
-                                         int include_count, unsigned long long max_size,
-                                         unsigned long long min_size, int num_threads);
-Chunk* parallel_scanner_next(ParallelScanner* scanner);
-void parallel_scanner_destroy(ParallelScanner* scanner);
-
 #endif

src/server/server.c

@@ -135,6 +135,7 @@ static void print_server_usage(void) {
   printf("  --ca <path>         TLS CA certificate file (PEM)\n");
   printf("  -v, --verbose       Enable debug logging\n");
   printf("  --help              Show this help\n");
+  printf("  -V, --version       Show version and exit\n");
 }
 
 int main(int argc, char* argv[]) {
@@ -149,6 +150,9 @@ int main(int argc, char* argv[]) {
     if (strcmp(argv[i], "--help") == 0) {
       print_server_usage();
       return 0;
+    } else if (strcmp(argv[i], "-V") == 0 || strcmp(argv[i], "--version") == 0) {
+      printf("fastsync-server version %s\n", PROTOCOL_VERSION);
+      return 0;
     } else if (strcmp(argv[i], "--stdio") == 0) {
       io_set_fds(STDIN_FILENO, STDOUT_FILENO);
       handler(STDIN_FILENO);

src/shared/compression.c

@@ -2,28 +2,10 @@
 #include "data.h"
 #include "log.h"
 #include "stdlib.h"
-#include "string.h"
-#include <strings.h>
 #include "zstd.h"
 
 #define INITIAL_DECOMPRESS_BUF_SIZE (1024 * 1024)
 
-static const char* SKIP_COMPRESSION_EXTENSIONS[] = {".jpg", ".jpeg", ".png", ".gif", ".mp4", ".mkv",
-                                                    ".zip", ".gz",   ".xz",  ".zst", NULL};
-
-bool compression_should_skip(const char* path) {
-  if (!path)
-    return false;
-  const char* dot = strrchr(path, '.');
-  if (!dot)
-    return false;
-  for (int i = 0; SKIP_COMPRESSION_EXTENSIONS[i]; i++) {
-    if (strcasecmp(dot, SKIP_COMPRESSION_EXTENSIONS[i]) == 0)
-      return true;
-  }
-  return false;
-}
-
 Data* data_compress(Data* data_to_compress, int compression_level) {
   log_message(LOG_LEVEL_DEBUG, "Starting to compress data");
   size_t dst_size = ZSTD_compressBound(data_to_compress->size);

src/shared/compression.h

@@ -2,10 +2,8 @@
 #define COMPRESSION_H
 
 #include "data.h"
-#include <stdbool.h>
 
 Data* data_compress(Data* data_to_compress, int compression_level);
 Data* data_decompress(Data* compressed_data);
-bool compression_should_skip(const char* path);
 
 #endif

src/shared/config.c

@@ -14,6 +14,8 @@ Config* config_create(char* version, char* send_directory, char* receive_directo
                       bool use_sendfile, unsigned long long chunk_size) {
 
   Config* config = malloc(sizeof(Config));
+  if (config == NULL)
+    return NULL;
   config->version = version;
   config->send_directory = send_directory;
   config->receive_root_directory = receive_directory;

src/shared/config.h

@@ -42,7 +42,7 @@ typedef struct Config {
   char* tls_ca;
 } Config;
 
-#define PROTOCOL_VERSION "1.3.0"
+#define PROTOCOL_VERSION "2.0.0"
 #define DEFAULT_CHUNK_SIZE (10 * 1024 * 1024)
 
 Config* config_create(char* version, char* send_directory, char* receive_directory,

src/shared/data.h

@@ -1,7 +1,7 @@
 #ifndef DATA_H
 #define DATA_H
 
-#include "stdlib.h"
+#include <stdlib.h>
 
 typedef struct {
   void* data;

src/shared/file.c

@@ -1,4 +1,5 @@
 #include <dirent.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <libgen.h>
 #include <stddef.h>
@@ -34,7 +35,7 @@ File* file_create(const char* path) {
     return NULL;
   }
 
-  strcpy(file->path, path);
+  memcpy(file->path, path, path_len + 1);
   file->data = data_create_reserve(0);
   if (file->data == NULL) {
     free(file->path);
@@ -102,7 +103,7 @@ bool file_send_single_calls(File* file, int file_descriptor, bool use_metadata,
                             int compression_level, bool send_path) {
   const Data* data_to_send = file->data;
   Data* compressed_data = NULL;
-  if (compression_level > 0 && !compression_should_skip(file->path)) {
+  if (compression_level > 0) {
     compressed_data = data_compress(file->data, compression_level);
     if (compressed_data == NULL) {
       log_message(LOG_LEVEL_ERROR, "Failed to compress file data");

src/shared/log.c

@@ -14,7 +14,8 @@ void log_message(LogLevel log_level, char* format, ...) {
   if (log_level < current_log_level)
     return;
   time_t now = time(NULL);
-  const struct tm* t = localtime(&now);
+  struct tm result_buf;
+  const struct tm* t = localtime_r(&now, &result_buf);
 
   fprintf(stderr, "%04d-%02d-%02d %02d:%02d:%02d [%s]: ", t->tm_year + 1900, t->tm_mon + 1,
           t->tm_mday, t->tm_hour, t->tm_min, t->tm_sec, log_level_strings[log_level]);

src/shared/metadata.c

@@ -4,67 +4,103 @@
 #include "protocol.h"
 #include <errno.h>
 #include <fcntl.h>
+#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <time.h>
 #include <unistd.h>
 
+/*
+ * Wire format serialization (protocol version 2.0.0+):
+ * All metadata fields are serialized as fixed-width integers (int32_t / int64_t)
+ * to ensure cross-platform binary compatiblity.  See metadata.h for the
+ * exact wire layout.
+ *
+ * Compile-time assertions verify that the native platform types fit within
+ * the chosen fixed-width representations.
+ */
+typedef char static_assert_mode_t_fits[(sizeof(mode_t) <= sizeof(int32_t)) ? 1 : -1];
+typedef char static_assert_uid_t_fits[(sizeof(uid_t) <= sizeof(int32_t)) ? 1 : -1];
+typedef char static_assert_gid_t_fits[(sizeof(gid_t) <= sizeof(int32_t)) ? 1 : -1];
+
 void metadata_to_buf(char** buf, const FileMetadata* m) {
-  int present = (m != NULL) ? 1 : 0;
-  memcpy(*buf, &present, sizeof(int));
-  *buf += sizeof(int);
+  int32_t present = (m != NULL) ? 1 : 0;
+  memcpy(*buf, &present, sizeof(present));
+  *buf += sizeof(present);
   if (m == NULL)
     return;
-  memcpy(*buf, &m->mode, sizeof(mode_t));
-  *buf += sizeof(mode_t);
-  memcpy(*buf, &m->uid, sizeof(uid_t));
-  *buf += sizeof(uid_t);
-  memcpy(*buf, &m->gid, sizeof(gid_t));
-  *buf += sizeof(gid_t);
-  memcpy(*buf, &m->mtime_sec, sizeof(time_t));
-  *buf += sizeof(time_t);
-  memcpy(*buf, &m->mtime_nsec, sizeof(long));
-  *buf += sizeof(long);
+  int32_t mode = (int32_t)m->mode;
+  memcpy(*buf, &mode, sizeof(mode));
+  *buf += sizeof(mode);
+  int32_t uid = (int32_t)m->uid;
+  memcpy(*buf, &uid, sizeof(uid));
+  *buf += sizeof(uid);
+  int32_t gid = (int32_t)m->gid;
+  memcpy(*buf, &gid, sizeof(gid));
+  *buf += sizeof(gid);
+  int64_t mtime_sec = (int64_t)m->mtime_sec;
+  memcpy(*buf, &mtime_sec, sizeof(mtime_sec));
+  *buf += sizeof(mtime_sec);
+  int64_t mtime_nsec = (int64_t)m->mtime_nsec;
+  memcpy(*buf, &mtime_nsec, sizeof(mtime_nsec));
+  *buf += sizeof(mtime_nsec);
 }
 
 FileMetadata* metadata_from_buf(char** buf) {
-  int present;
-  memcpy(&present, *buf, sizeof(int));
-  *buf += sizeof(int);
+  int32_t present;
+  memcpy(&present, *buf, sizeof(present));
+  *buf += sizeof(present);
   if (!present)
     return NULL;
   FileMetadata* m = malloc(sizeof(FileMetadata));
-  memcpy(&m->mode, *buf, sizeof(mode_t));
-  *buf += sizeof(mode_t);
-  memcpy(&m->uid, *buf, sizeof(uid_t));
-  *buf += sizeof(uid_t);
-  memcpy(&m->gid, *buf, sizeof(gid_t));
-  *buf += sizeof(gid_t);
-  memcpy(&m->mtime_sec, *buf, sizeof(time_t));
-  *buf += sizeof(time_t);
-  memcpy(&m->mtime_nsec, *buf, sizeof(long));
-  *buf += sizeof(long);
+  if (m == NULL)
+    return NULL;
+  int32_t mode;
+  memcpy(&mode, *buf, sizeof(mode));
+  *buf += sizeof(mode);
+  m->mode = (mode_t)mode;
+  int32_t uid;
+  memcpy(&uid, *buf, sizeof(uid));
+  *buf += sizeof(uid);
+  m->uid = (uid_t)uid;
+  int32_t gid;
+  memcpy(&gid, *buf, sizeof(gid));
+  *buf += sizeof(gid);
+  m->gid = (gid_t)gid;
+  int64_t mtime_sec;
+  memcpy(&mtime_sec, *buf, sizeof(mtime_sec));
+  *buf += sizeof(mtime_sec);
+  m->mtime_sec = (time_t)mtime_sec;
+  int64_t mtime_nsec;
+  memcpy(&mtime_nsec, *buf, sizeof(mtime_nsec));
+  *buf += sizeof(mtime_nsec);
+  m->mtime_nsec = (long)mtime_nsec;
   return m;
 }
 
 bool metadata_send(int file_descriptor, FileMetadata* m) {
   if (m == NULL) {
-    int zero = 0;
-    return send_n_data(file_descriptor, &zero, sizeof(int));
+    int32_t zero = 0;
+    return send_n_data(file_descriptor, &zero, sizeof(zero));
   }
-  int present = 1;
-  return send_n_data(file_descriptor, &present, sizeof(int)) &&
-         send_n_data(file_descriptor, &m->mode, sizeof(mode_t)) &&
-         send_n_data(file_descriptor, &m->uid, sizeof(uid_t)) &&
-         send_n_data(file_descriptor, &m->gid, sizeof(gid_t)) &&
-         send_n_data(file_descriptor, &m->mtime_sec, sizeof(time_t)) &&
-         send_n_data(file_descriptor, &m->mtime_nsec, sizeof(long));
+  int32_t present = 1;
+  int32_t mode = (int32_t)m->mode;
+  int32_t uid = (int32_t)m->uid;
+  int32_t gid = (int32_t)m->gid;
+  int64_t mtime_sec = (int64_t)m->mtime_sec;
+  int64_t mtime_nsec = (int64_t)m->mtime_nsec;
+  return send_n_data(file_descriptor, &present, sizeof(present)) &&
+         send_n_data(file_descriptor, &mode, sizeof(mode)) &&
+         send_n_data(file_descriptor, &uid, sizeof(uid)) &&
+         send_n_data(file_descriptor, &gid, sizeof(gid)) &&
+         send_n_data(file_descriptor, &mtime_sec, sizeof(mtime_sec)) &&
+         send_n_data(file_descriptor, &mtime_nsec, sizeof(mtime_nsec));
 }
 
 FileMetadata* metadata_receive(int file_descriptor, int* ok) {
-  int present;
-  if (!receive_n_data(file_descriptor, &present, sizeof(int))) {
+  int32_t present;
+  if (!receive_n_data(file_descriptor, &present, sizeof(present))) {
     if (ok)
       *ok = 0;
     return NULL;
@@ -80,16 +116,46 @@ FileMetadata* metadata_receive(int file_descriptor, int* ok) {
       *ok = 0;
     return NULL;
   }
-  if (!receive_n_data(file_descriptor, &m->mode, sizeof(mode_t)) ||
-      !receive_n_data(file_descriptor, &m->uid, sizeof(uid_t)) ||
-      !receive_n_data(file_descriptor, &m->gid, sizeof(gid_t)) ||
-      !receive_n_data(file_descriptor, &m->mtime_sec, sizeof(time_t)) ||
-      !receive_n_data(file_descriptor, &m->mtime_nsec, sizeof(long))) {
+  int32_t mode;
+  if (!receive_n_data(file_descriptor, &mode, sizeof(mode))) {
     free(m);
     if (ok)
       *ok = 0;
     return NULL;
   }
+  m->mode = (mode_t)mode;
+  int32_t uid;
+  if (!receive_n_data(file_descriptor, &uid, sizeof(uid))) {
+    free(m);
+    if (ok)
+      *ok = 0;
+    return NULL;
+  }
+  m->uid = (uid_t)uid;
+  int32_t gid;
+  if (!receive_n_data(file_descriptor, &gid, sizeof(gid))) {
+    free(m);
+    if (ok)
+      *ok = 0;
+    return NULL;
+  }
+  m->gid = (gid_t)gid;
+  int64_t mtime_sec;
+  if (!receive_n_data(file_descriptor, &mtime_sec, sizeof(mtime_sec))) {
+    free(m);
+    if (ok)
+      *ok = 0;
+    return NULL;
+  }
+  m->mtime_sec = (time_t)mtime_sec;
+  int64_t mtime_nsec;
+  if (!receive_n_data(file_descriptor, &mtime_nsec, sizeof(mtime_nsec))) {
+    free(m);
+    if (ok)
+      *ok = 0;
+    return NULL;
+  }
+  m->mtime_nsec = (long)mtime_nsec;
   if (ok)
     *ok = 1;
   return m;

src/shared/metadata.h

@@ -3,10 +3,24 @@
 
 #include "file.h"
 #include <stdbool.h>
+#include <stdint.h>
 #include <sys/stat.h>
 
-#define FILE_METADATA_WIRE_SIZE                                                                    \
-  (sizeof(mode_t) + sizeof(uid_t) + sizeof(gid_t) + sizeof(time_t) + sizeof(long))
+/*
+ * Wire format (introduced in protocol version 2.0.0):
+ *   int32_t present
+ *   int32_t mode    (was mode_t, platform-dependent)
+ *   int32_t uid     (was uid_t,  platform-dependent)
+ *   int32_t gid     (was gid_t,  platform-dependent)
+ *   int64_t mtime_sec (was time_t, platform-dependent)
+ *   int64_t mtime_nsec (was long,  platform-dependent)
+ *
+ * Prior to 2.0.0 the wire format used the raw platform-dependent types,
+ * which broke compatiblity across different systems.  All fields are now
+ * serialized as fixed-width integers.
+ */
+
+#define FILE_METADATA_WIRE_SIZE (sizeof(int32_t) * 3 + sizeof(int64_t) * 2)
 
 void metadata_to_buf(char** buf, const FileMetadata* m);
 FileMetadata* metadata_from_buf(char** buf);

src/shared/protocol.c

@@ -2,7 +2,6 @@
 #include "log.h"
 #include <errno.h>
 #include <openssl/ssl.h>
-#include <poll.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -11,7 +10,7 @@
 
 static __thread int io_read_fd = -1;
 static __thread int io_write_fd = -1;
-static SSL* io_ssl;
+static SSL* io_ssl = NULL;
 
 static unsigned long long io_bwlimit = 0;
 static long long bw_tokens = 0;
@@ -47,11 +46,12 @@ static void bw_throttle(size_t bytes_written) {
   bw_tokens -= (long long)bytes_written;
 
   if (bw_tokens < 0) {
-    long long deficit_us = (long long)((double)(-bw_tokens) / io_bwlimit * 1000000.0);
-    if (deficit_us >= 1000)
-      poll(NULL, 0, (int)(deficit_us / 1000));
-    else
-      usleep((useconds_t)deficit_us);
+    long long deficit_ns = (long long)((double)(-bw_tokens) / io_bwlimit * 1000000000.0);
+    struct timespec sleep_time, remaining;
+    sleep_time.tv_sec = deficit_ns / 1000000000LL;
+    sleep_time.tv_nsec = deficit_ns % 1000000000LL;
+    while (nanosleep(&sleep_time, &remaining) < 0 && errno == EINTR)
+      sleep_time = remaining;
     bw_tokens = 0;
     clock_gettime(CLOCK_MONOTONIC, &bw_last_refill);
   }

src/shared/protocol.h

@@ -17,10 +17,7 @@ enum NET_STATUS {
   STATUS_MANIFEST,
   STATUS_CHECK,
   STATUS_DELTA_SIGNATURE,
-  STATUS_DELTA_DATA,
-  STATUS_KEEPALIVE,
-  STATUS_ABORT,
-  STATUS_CHECK_BATCH
+  STATUS_DELTA_DATA
 };
 
 void io_set_fds(int read_fd, int write_fd);

src/shared/utils.c

@@ -54,7 +54,7 @@ char* str_dup(const char* string) {
   if (string == NULL)
     return NULL;
   char* new_string = (char*)malloc(strlen(string) + 1);
-  strcpy(new_string, string);
+  memcpy(new_string, string, strlen(string) + 1);
   return new_string;
 }
 

tests/test_file.c

@@ -271,7 +271,7 @@ void test_file() {
   test_to_disk_basic();
   test_to_disk_creates_dirs();
   test_file_content_to_buffer();
-  if (!getenv("FASTSYNC_UNDER_VALGRIND")) {
+  if (!is_running_under_valgrind()) {
     // Fork tests are skipped under valgrind because the parent process runs
     // orders of magnitude slower than the child (parent is instrumented, child
     // is not), which causes pipe-based protocol handshake timeouts. The parent

tests/test_utils.h

@@ -2,9 +2,24 @@
 #define TEST_UTILS_H
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #include <stdbool.h>
 
+// Detect if running under valgrind by checking /proc/self/maps for vgpreload.
+// This is used to skip fork-based tests that are incompatible with valgrind
+// (the instrumented parent runs too slowly, causing pipe timeouts).
+static inline bool is_running_under_valgrind(void) {
+  FILE* f = fopen("/proc/self/maps", "r");
+  if (!f)
+    return false;
+  char buf[4096];
+  size_t n = fread(buf, 1, sizeof(buf) - 1, f);
+  fclose(f);
+  buf[n] = '\0';
+  return strstr(buf, "vgpreload") != NULL;
+}
+
 // Global test suite status
 extern int tests_run;
 extern int tests_failed;