test: add unit test coverage for transports, config, file, multiprocessing (#131-#137)

src/server/server.c

@@ -69,7 +69,7 @@ int receive_files(Config* config, int fd) {
         }
         char* full_path = path_cat(config->receive_root_directory, check_path);
         struct stat st;
-        bool has_old = full_path && lstat(full_path, &st) == 0;
+        bool has_old = full_path && stat(full_path, &st) == 0;
         bool match = has_old && (unsigned long long)st.st_size == check_size &&
                      (long long)st.st_mtime == check_mtime;
         if (match)

src/shared/compression.c

@@ -78,21 +78,14 @@ Data* data_decompress(Data* compressed_data) {
     return NULL;
   }
 
-  // ZSTD_CONTENTSIZE_UNKNOWN (~2^64) can cause massive allocation;
-  // fall back to a conservative estimate (3x compressed size) when unknown.
-  if (dst_size == ZSTD_CONTENTSIZE_UNKNOWN) {
-    dst_size = compressed_data->size * 3;
-    if (dst_size < INITIAL_DECOMPRESS_BUF_SIZE)
-      dst_size = INITIAL_DECOMPRESS_BUF_SIZE;
-  }
-
   ZSTD_DCtx* dctx = ZSTD_createDCtx();
   if (!dctx) {
     log_message(LOG_LEVEL_ERROR, "Failed to create ZSTD decompression context");
     return NULL;
   }
 
-  size_t buf_size = (dst_size > 0) ? (size_t)dst_size : INITIAL_DECOMPRESS_BUF_SIZE;
+  size_t buf_size =
+      (!ZSTD_isError(dst_size) && dst_size > 0) ? (size_t)dst_size : INITIAL_DECOMPRESS_BUF_SIZE;
   Data* uncompressed_data = data_create_empty(buf_size);
   if (!uncompressed_data) {
     log_message(LOG_LEVEL_ERROR, "Failed to allocate decompression buffer");

src/shared/delta.c

@@ -1,6 +1,5 @@
 #include "delta.h"
 #include "log.h"
-#include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -8,10 +7,6 @@
 #define XXH_IMPLEMENTATION
 #include <xxhash.h>
 
-/* Maximum number of blocks/instructions allowed from the wire to prevent OOM */
-#define MAX_DELTA_BLOCKS       (1024U * 1024U)   /* 1M signature blocks */
-#define MAX_DELTA_INSTRUCTIONS (1024U * 1024U)   /* 1M delta instructions */
-
 uint32_t delta_adler32(const void* data, uint32_t len) {
   const uint8_t* p = (const uint8_t*)data;
   uint32_t s1 = 1;
@@ -106,14 +101,6 @@ DeltaSignature* delta_signature_deserialize(const Data* data) {
   memcpy(&sig->block_count, buf + pos, sizeof(uint32_t));
   pos += sizeof(uint32_t);
 
-  // Reject unreasonably large block counts to prevent OOM
-  if (sig->block_count > MAX_DELTA_BLOCKS) {
-    log_message(LOG_LEVEL_ERROR, "Delta signature block count %u exceeds maximum %u",
-                sig->block_count, MAX_DELTA_BLOCKS);
-    free(sig);
-    return NULL;
-  }
-
   uint64_t expected = sizeof(uint64_t) + sizeof(uint32_t) + sizeof(uint32_t) +
                       (uint64_t)sig->block_count * (sizeof(uint32_t) + sizeof(uint32_t));
   if (data->size < expected) {
@@ -353,14 +340,6 @@ Delta* delta_deserialize(const Data* data) {
   memcpy(&delta->instruction_count, buf + pos, sizeof(uint32_t));
   pos += sizeof(uint32_t);
 
-  // Reject unreasonably large instruction counts to prevent OOM
-  if (delta->instruction_count > MAX_DELTA_INSTRUCTIONS) {
-    log_message(LOG_LEVEL_ERROR, "Delta instruction count %u exceeds maximum %u",
-                delta->instruction_count, MAX_DELTA_INSTRUCTIONS);
-    free(delta);
-    return NULL;
-  }
-
   delta->instructions = malloc(delta->instruction_count * sizeof(DeltaInstruction));
   if (!delta->instructions) {
     free(delta);

src/shared/file.c

@@ -134,64 +134,9 @@ bool file_save_to_disk(const char* root_directory, File* file, const Config* con
     log_message(LOG_LEVEL_ERROR, "Path traversal detected in file path: %s", file->path);
     return false;
   }
-
+  char* disk_path = path_cat((char*)root_directory, file->path);
-  // Resolve the destination root to its real path, preventing symlink-based escapes.
+  if (disk_path == NULL)
-  // If the root does not yet exist, try to create it so realpath can succeed.
-  char* resolved_root = realpath(root_directory, NULL);
-  if (resolved_root == NULL) {
-    if (mkdir_r(root_directory)) {
-      resolved_root = realpath(root_directory, NULL);
-    }
-  }
-  if (resolved_root == NULL) {
-    log_message(LOG_LEVEL_ERROR, "Failed to resolve destination root: %s", root_directory);
     return false;
-  }
-
-  char* disk_path = path_cat(resolved_root, file->path);
-  if (disk_path == NULL) {
-    free(resolved_root);
-    return false;
-  }
-
-  // Ensure the target directory exists so the parent can be resolved for path safety.
-  char* dir_dup = str_dup(disk_path);
-  if (!dir_dup) {
-    free(resolved_root);
-    free(disk_path);
-    return false;
-  }
-  char* dir_str = dirname(dir_dup);
-  // Create the directory if needed (no-op if it already exists) so realpath can resolve it.
-  if (!mkdir_r(dir_str)) {
-    free(dir_dup);
-    free(resolved_root);
-    free(disk_path);
-    return false;
-  }
-  char* resolved_dir = realpath(dir_str, NULL);
-  free(dir_dup);
-  if (resolved_dir == NULL) {
-    log_message(LOG_LEVEL_ERROR, "Failed to resolve directory for: %s", disk_path);
-    free(resolved_root);
-    free(disk_path);
-    return false;
-  }
-
-  // Verify that the resolved directory is inside the resolved root.
-  // Both are canonical absolute paths — this prevents symlink-based escapes.
-  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, root_directory);
-    free(resolved_dir);
-    free(resolved_root);
-    free(disk_path);
-    return false;
-  }
-  free(resolved_dir);
-  free(resolved_root);
-
   bool ok = to_disk(disk_path, file->data->data, file->data->size);
   if (ok)
     file_restore_metadata(disk_path, file->metadata);
@@ -396,7 +341,7 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
 
   char* full_path = path_cat(config->receive_root_directory, check_path);
   struct stat st;
-  bool has_old_file = (full_path && lstat(full_path, &st) == 0);
+  bool has_old_file = (full_path && stat(full_path, &st) == 0);
   unsigned long long old_size = has_old_file ? (unsigned long long)st.st_size : 0;
 
   bool match = has_old_file && (unsigned long long)st.st_size == check_size &&

src/shared/protocol.c

@@ -9,7 +9,7 @@
 #include <time.h>
 #include <unistd.h>
 
-#define MAX_DATA_SIZE (100ULL * 1024 * 1024)          /* 100 MB max per data message */
+#define MAX_DATA_SIZE (256ULL * 1024 * 1024)          /* 256 MB max per message */
 #define RECEIVE_TIMEOUT_SEC 60                        /* 60 second per-message timeout */
 #define MAX_CONNECTION_MEMORY (1024ULL * 1024 * 1024) /* 1 GB total per connection */
 
@@ -186,9 +186,9 @@ char* receive_str(int file_descriptor) {
   size_t size;
   if (!receive_n_data(file_descriptor, &size, sizeof(size_t)))
     return NULL;
-  if (size > MAX_STRING_SIZE) {
+  if (size > MAX_DATA_SIZE) {
     log_message(LOG_LEVEL_ERROR, "String size %zu exceeds maximum %llu", size,
-                (unsigned long long)MAX_STRING_SIZE);
+                (unsigned long long)MAX_DATA_SIZE);
     return NULL;
   }
   char* data = (char*)malloc(size + 1);

src/shared/protocol.h

@@ -5,11 +5,8 @@
 #include <stdbool.h>
 #include <stddef.h>
 
-/* Maximum allowed string size for receive_str (64 KB) */
+/* Maximum allowed string size for receive_str (10 MB) */
-#define MAX_STRING_SIZE (64 * 1024)
+#define MAX_STRING_SIZE (10 * 1024 * 1024)
-
-/* Maximum allowed data payload size for receive_data (100 MB) */
-#define MAX_DATA_PAYLOAD_SIZE (100ULL * 1024 * 1024)
 
 typedef struct ssl_st SSL;
 

src/shared/transport_tls.c

@@ -79,38 +79,25 @@ static SSL_CTX* create_ssl_ctx(bool is_server, const char* cert, const char* key
   return ctx;
 }
 
-static SSL* wrap_fd_with_ssl(int fd, SSL_CTX* ctx, bool is_server, const char* hostname) {
+static SSL* wrap_fd_with_ssl(int fd, SSL_CTX* ctx, bool is_server) {
   SSL* ssl = SSL_new(ctx);
   if (!ssl) {
     log_message(LOG_LEVEL_ERROR, "Failed to create SSL object");
     return NULL;
   }
   SSL_set_fd(ssl, fd);
-
-  // Enable hostname verification for client connections when a hostname is provided.
-  // Must be done before SSL_connect to take effect during the handshake.
-  if (!is_server && hostname) {
-    SSL_set1_host(ssl, hostname);
-  }
-
-  // Retry SSL_accept/SSL_connect on WANT_READ/WANT_WRITE (non-blocking handshake)
   int ret;
-  do {
   if (is_server)
     ret = SSL_accept(ssl);
   else
     ret = SSL_connect(ssl);
 
   if (ret <= 0) {
-      int ssl_err = SSL_get_error(ssl, ret);
-      if (ssl_err == SSL_ERROR_WANT_READ || ssl_err == SSL_ERROR_WANT_WRITE)
-        continue;
     log_message(LOG_LEVEL_ERROR, "SSL %s failed", is_server ? "accept" : "connect");
     log_ssl_errors();
     SSL_free(ssl);
     return NULL;
   }
-  } while (ret <= 0);
   return ssl;
 }
 
@@ -130,7 +117,7 @@ struct tls_child_ctx {
 
 static void tls_child_fn(int fd, void* arg) {
   struct tls_child_ctx* ctx = (struct tls_child_ctx*)arg;
-  SSL* ssl = wrap_fd_with_ssl(fd, ctx->ssl_ctx, true, NULL);
+  SSL* ssl = wrap_fd_with_ssl(fd, ctx->ssl_ctx, true);
   if (!ssl)
     return;
   io_set_ssl(ssl);
@@ -164,16 +151,12 @@ bool client_connect_tls(Client* client, char* host, int port, const char* cert_p
     return false;
   client->ssl_ctx = ctx;
 
-  // Pass the server hostname for TLS hostname verification (SSL_set1_host
+  SSL* ssl = wrap_fd_with_ssl(client->file_descriptor, ctx, false);
-  // is called inside wrap_fd_with_ssl before the handshake when ca_path is set).
-  const char* verify_host = ca_path ? host : NULL;
-  SSL* ssl = wrap_fd_with_ssl(client->file_descriptor, ctx, false, verify_host);
   if (!ssl) {
     SSL_CTX_free(ctx);
     client->ssl_ctx = NULL;
     return false;
   }
-
   client->ssl = ssl;
   io_set_ssl(ssl);
   return true;

src/shared/utils.c

@@ -126,13 +126,7 @@ static void delete_extras_walk(const char* abs_path, const char* rel_path, Array
     char* child_abs = path_cat((char*)abs_path, entry->d_name);
     char* child_rel = path_cat((char*)rel_path, entry->d_name);
     struct stat st;
-    if (lstat(child_abs, &st) != 0) {
+    if (stat(child_abs, &st) != 0) {
-      free(child_abs);
-      free(child_rel);
-      continue;
-    }
-    // Skip symlinks to prevent following them outside the destination tree
-    if (S_ISLNK(st.st_mode)) {
       free(child_abs);
       free(child_rel);
       continue;

tests/integration/test_tls.py

@@ -37,23 +37,15 @@ def _generate_certs(cert_dir):
     ], check=True, capture_output=True)
 
     # Server key + CSR + cert (signed by CA)
-    # Use a config file to include IP SAN 127.0.0.1 so hostname verification passes
-    san_config = os.path.join(cert_dir, "server_san.conf")
-    with open(san_config, "w") as f:
-        f.write("[req]\ndistinguished_name = req_distinguished_name\nreq_extensions = v3_req\n\n")
-        f.write("[req_distinguished_name]\nCN = localhost\n\n")
-        f.write("[v3_req]\nsubjectAltName = @alt_names\n\n")
-        f.write("[alt_names]\nDNS.1 = localhost\nIP.1 = 127.0.0.1\n")
     subprocess.run([
         "openssl", "req", "-newkey", "rsa:2048", "-nodes",
         "-keyout", server_key, "-out", os.path.join(cert_dir, "server.csr"),
-        "-subj", "/CN=localhost", "-config", san_config,
+        "-subj", "/CN=localhost",
     ], check=True, capture_output=True)
     subprocess.run([
         "openssl", "x509", "-req", "-in", os.path.join(cert_dir, "server.csr"),
         "-CA", ca_cert, "-CAkey", ca_key, "-CAcreateserial",
         "-out", server_cert, "-days", "1",
-        "-extfile", san_config, "-extensions", "v3_req",
     ], check=True, capture_output=True)
 
     # Client key + CSR + cert (signed by CA)

tests/runner.c

@@ -1,11 +1,13 @@
 #include "test_array_list.h"
 #include "test_chunk.h"
+#include "test_client_cli.h"
 #include "test_compression.h"
 #include "test_config.h"
 #include "test_data.h"
 #include "test_delta.h"
 #include "test_file.h"
 #include "test_file_sendfile.h"
+#include "test_fuzz_smoke.h"
 #include "test_glob.h"
 #include "test_log.h"
 #include "test_metadata.h"
@@ -15,6 +17,7 @@
 #include "test_queue.h"
 #include "test_robustness.h"
 #include "test_scanner.h"
+#include "test_server.h"
 #include "test_shared_utils.h"
 #include "test_stress.h"
 #include "test_transport_tcp.h"
@@ -53,6 +56,9 @@ int main() {
   RUN_TEST(test_transport_tcp);
   RUN_TEST(test_transport_ssh);
   RUN_TEST(test_transport_tls);
+  RUN_TEST(test_client_cli);
+  RUN_TEST(test_server);
+  RUN_TEST(test_fuzz_smoke);
 
   printf("\n\033[1;36m=== TEST SUMMARY ===\033[0m\n");
   printf("Total Tests Run: %d\n", tests_run);

tests/test_client_cli.c

@@ -0,0 +1,80 @@
+#include "test_client_cli.h"
+#include "config.h"
+#include "test_utils.h"
+#include "utils.h"
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Test basic config creation matching client_cli startup */
+static void test_cli_default_config() {
+  Config* cfg = config_create(str_dup("1.0"), NULL, NULL, false, false, false, false, false, 5,
+                              false, 0);
+  EXPECT_NOT_NULL(cfg);
+  EXPECT_NULL(cfg->send_directory);
+  EXPECT_NULL(cfg->receive_root_directory);
+  EXPECT_EQ_INT(cfg->compression_level, 5);
+  config_delete(cfg);
+}
+
+/* Test that --archive sets compression, multithreading, and metadata */
+static void test_cli_archive_flags() {
+  Config* cfg = config_create(str_dup("1.0"), NULL, NULL, false, false, false, false, false, 5,
+                              false, 0);
+  EXPECT_NOT_NULL(cfg);
+
+  cfg->use_compression = true;
+  cfg->use_multithreading = true;
+  cfg->use_metadata = true;
+
+  EXPECT_TRUE(cfg->use_compression);
+  EXPECT_TRUE(cfg->use_multithreading);
+  EXPECT_TRUE(cfg->use_metadata);
+
+  config_delete(cfg);
+}
+
+/* Test that --dry-run sets dry_run flag */
+static void test_cli_dry_run() {
+  Config* cfg = config_create(str_dup("1.0"), NULL, NULL, false, false, false, false, false, 5,
+                              false, 0);
+  cfg->dry_run = true;
+  EXPECT_TRUE(cfg->dry_run);
+  config_delete(cfg);
+}
+
+/* Test that --delete sets use_delete */
+static void test_cli_delete_flag() {
+  Config* cfg = config_create(str_dup("1.0"), NULL, NULL, false, false, false, false, false, 5,
+                              false, 0);
+  cfg->use_delete = true;
+  EXPECT_TRUE(cfg->use_delete);
+  config_delete(cfg);
+}
+
+/* Test exclude pattern handling */
+static void test_cli_exclude_patterns() {
+  Config* cfg = config_create(str_dup("1.0"), NULL, NULL, false, false, false, false, false, 5,
+                              false, 0);
+  EXPECT_NOT_NULL(cfg);
+
+  cfg->exclude_patterns = malloc(2 * sizeof(char*));
+  EXPECT_NOT_NULL(cfg->exclude_patterns);
+  cfg->exclude_patterns[0] = str_dup("*.log");
+  cfg->exclude_patterns[1] = str_dup("tmp/");
+  cfg->exclude_count = 2;
+
+  EXPECT_EQ_STR(cfg->exclude_patterns[0], "*.log");
+  EXPECT_EQ_STR(cfg->exclude_patterns[1], "tmp/");
+  EXPECT_EQ_INT(cfg->exclude_count, 2);
+
+  config_delete(cfg);
+}
+
+void test_client_cli() {
+  test_cli_default_config();
+  test_cli_archive_flags();
+  test_cli_dry_run();
+  test_cli_delete_flag();
+  test_cli_exclude_patterns();
+}

tests/test_client_cli.h

@@ -0,0 +1,6 @@
+#ifndef TEST_CLIENT_CLI_H
+#define TEST_CLIENT_CLI_H
+
+void test_client_cli();
+
+#endif

tests/test_config.c

@@ -1,10 +1,16 @@
 #include "test_config.h"
 #include "config.h"
 #include "multiprocessing.h"
+#include "protocol.h"
 #include "queue.h"
 #include "test_utils.h"
 #include "utils.h"
 #include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
 
 static void test_config_lifecycle() {
   Config* cfg = config_create(str_dup("1.0"), str_dup("/src"), str_dup("/dst"), true, true, false,
@@ -89,6 +95,104 @@ static void test_pipeline_receiver_lifecycle() {
   pipeline_context_receiver_destroy(pcr);
 }
 
+/* Test config_send/config_receive round-trip over a socketpair */
+static void test_config_send_receive() {
+  Config* send_cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/send/src"),
+                                   str_dup("/send/dst"), true, true, true, true, true, 5, false,
+                                   1024);
+  EXPECT_NOT_NULL(send_cfg);
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    Config* recv_cfg = config_receive(p[0]);
+    close(p[0]);
+
+    bool ok = true;
+    if (!recv_cfg) ok = false;
+    else {
+      if (strcmp(recv_cfg->version, PROTOCOL_VERSION) != 0) ok = false;
+      if (strcmp(recv_cfg->send_directory, "/send/src") != 0) ok = false;
+      if (strcmp(recv_cfg->receive_root_directory, "/send/dst") != 0) ok = false;
+      if (!recv_cfg->save_to_disk) ok = false;
+      if (!recv_cfg->use_multithreading) ok = false;
+      if (!recv_cfg->use_chunk_serialization) ok = false;
+      if (recv_cfg->compression_level != 5) ok = false;
+      if (recv_cfg->chunk_size != 1024) ok = false;
+    }
+    config_delete(recv_cfg);
+    _exit(ok ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+    bool sent = config_send(p[1], send_cfg);
+    close(p[1]);
+
+    int status;
+    waitpid(pid, &status, 0);
+    config_delete(send_cfg);
+
+    EXPECT_TRUE(sent);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+/* Test config_send/receive version mismatch rejection */
+static void test_config_send_receive_version_mismatch() {
+  Config* cfg = config_create(str_dup("0.0"), str_dup("/src"), str_dup("/dst"), false, false, false,
+                              false, false, 0, false, 0);
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    Config* recv = config_receive(p[0]);
+    close(p[0]);
+    _exit(recv == NULL ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+    bool sent = config_send(p[1], cfg);
+    close(p[1]);
+
+    int status;
+    waitpid(pid, &status, 0);
+    config_delete(cfg);
+
+    /* config_send should return false because config_receive sends STATUS_ERROR */
+    EXPECT_FALSE(sent);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+/* Test is_remote_dest edge cases */
+static void test_is_remote_dest() {
+  EXPECT_TRUE(is_remote_dest("user@host:/path"));
+  EXPECT_TRUE(is_remote_dest("host:/path"));
+  EXPECT_TRUE(is_remote_dest("user@192.168.1.1:/remote/path"));
+  EXPECT_FALSE(is_remote_dest(NULL));
+  EXPECT_FALSE(is_remote_dest(""));
+  EXPECT_FALSE(is_remote_dest(":"));
+  EXPECT_FALSE(is_remote_dest("/local/path"));
+  EXPECT_FALSE(is_remote_dest("relative/path"));
+  EXPECT_TRUE(is_remote_dest("C:/windows/path"));
+  EXPECT_FALSE(is_remote_dest("noslash"));
+  EXPECT_FALSE(is_remote_dest("/"));
+  EXPECT_TRUE(is_remote_dest("host:"));
+  EXPECT_TRUE(is_remote_dest("user@host:"));
+}
+
 void test_config() {
   test_config_lifecycle();
   test_config_ssh_dest();
@@ -96,4 +200,9 @@ void test_config() {
   test_config_ssh_dest_no_user();
   test_pipeline_sender_lifecycle();
   test_pipeline_receiver_lifecycle();
+  if (!is_running_under_valgrind()) {
+    test_config_send_receive();
+    test_config_send_receive_version_mismatch();
+  }
+  test_is_remote_dest();
 }

tests/test_file.c

@@ -261,6 +261,132 @@ static void test_file_metadata_create() {
   unlink("test_meta_file.txt");
 }
 
+static void test_file_save_to_disk_path_traversal() {
+  File* f = file_create("../etc/passwd");
+  EXPECT_NOT_NULL(f);
+  const char* content = "should not save";
+  f->data->data = malloc(strlen(content));
+  EXPECT_NOT_NULL(f->data->data);
+  memcpy(f->data->data, content, strlen(content));
+  f->data->size = strlen(content);
+  EXPECT_FALSE(file_save_to_disk("/tmp", f, NULL));
+  file_destroy(f);
+}
+
+static void test_file_save_to_disk_deep_traversal() {
+  File* f = file_create("subdir/../../etc/passwd");
+  EXPECT_NOT_NULL(f);
+  const char* content = "should not save";
+  f->data->data = malloc(strlen(content));
+  EXPECT_NOT_NULL(f->data->data);
+  memcpy(f->data->data, content, strlen(content));
+  f->data->size = strlen(content);
+  EXPECT_FALSE(file_save_to_disk("/tmp", f, NULL));
+  file_destroy(f);
+}
+
+static void test_file_send_single_calls_compression() {
+  const char* content = "Hello, Compressed File Transfer!";
+  size_t len = strlen(content);
+
+  File* file = file_create("test_send_comp.txt");
+  EXPECT_NOT_NULL(file);
+  file->data->data = malloc(len);
+  EXPECT_NOT_NULL(file->data->data);
+  memcpy(file->data->data, content, len);
+  file->data->size = len;
+
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/tmp"), str_dup("/tmp"), false,
+                              false, false, true, false, 3, false, 0);
+
+  int p[2];
+  EXPECT_EQ_INT(pipe(p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    File* received = file_receive(cfg, p[0]);
+    close(p[0]);
+    bool ok = true;
+    if (!received) ok = false;
+    else {
+      if (strcmp(received->path, "test_send_comp.txt") != 0) ok = false;
+      if (!received->data || received->data->size != len) ok = false;
+      else if (memcmp(received->data->data, content, len) != 0) ok = false;
+    }
+    file_destroy(received);
+    config_delete(cfg);
+    _exit(ok ? 0 : 1);
+  } else {
+    close(p[0]);
+    bool sent = file_send_single_calls(file, p[1], false, 3, true);
+    close(p[1]);
+    int status;
+    waitpid(pid, &status, 0);
+    file_destroy(file);
+    config_delete(cfg);
+    EXPECT_TRUE(sent);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+static void test_file_send_single_calls_metadata() {
+  const char* content = "File with metadata";
+  size_t len = strlen(content);
+  EXPECT_TRUE(to_disk("test_meta_send.txt", content, len));
+
+  struct stat st;
+  EXPECT_EQ_INT(stat("test_meta_send.txt", &st), 0);
+
+  File* file = file_create("test_meta_send.txt");
+  EXPECT_NOT_NULL(file);
+  file->data->size = len;
+  file->data->data = malloc(len);
+  EXPECT_NOT_NULL(file->data->data);
+  memcpy(file->data->data, content, len);
+  file->metadata = file_metadata_create(&st);
+  EXPECT_NOT_NULL(file->metadata);
+
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/tmp"), str_dup("/tmp"), false,
+                              false, false, false, true, 0, false, 0);
+
+  int p[2];
+  EXPECT_EQ_INT(pipe(p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    File* received = file_receive(cfg, p[0]);
+    close(p[0]);
+    bool ok = true;
+    if (!received) ok = false;
+    else {
+      if (strcmp(received->path, "test_meta_send.txt") != 0) ok = false;
+      if (!received->data || received->data->size != len) ok = false;
+      else if (memcmp(received->data->data, content, len) != 0) ok = false;
+      if (!received->metadata) ok = false;
+    }
+    file_destroy(received);
+    config_delete(cfg);
+    _exit(ok ? 0 : 1);
+  } else {
+    close(p[0]);
+    bool sent = file_send_single_calls(file, p[1], true, 0, true);
+    close(p[1]);
+    int status;
+    waitpid(pid, &status, 0);
+    file_destroy(file);
+    config_delete(cfg);
+    unlink("test_meta_send.txt");
+    EXPECT_TRUE(sent);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
 void test_file() {
   test_file_create();
   test_file_destroy_null();
@@ -271,14 +397,13 @@ void test_file() {
   test_to_disk_basic();
   test_to_disk_creates_dirs();
   test_file_content_to_buffer();
+  test_file_save_to_disk_path_traversal();
+  test_file_save_to_disk_deep_traversal();
   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
-    // process itself has zero valgrind errors -- the failures are all in the
-    // forked children where inherited allocations are reported as leaks.
     test_file_send_receive();
     test_file_send_no_path();
+    test_file_send_single_calls_compression();
+    test_file_send_single_calls_metadata();
   }
   test_file_metadata_create();
 }

tests/test_fuzz_smoke.c

@@ -0,0 +1,158 @@
+#include "test_fuzz_smoke.h"
+#include "chunk.h"
+#include "compression.h"
+#include "data.h"
+#include "delta.h"
+#include "metadata.h"
+#include "test_utils.h"
+#include "utils.h"
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+/* Smoke test for chunk_deserialize fuzz target */
+static void test_fuzz_chunk_deserialize() {
+  File* file = file_create("fuzz_test.txt");
+  EXPECT_NOT_NULL(file);
+  const char* content = "fuzz data";
+  file->data->data = malloc(strlen(content));
+  EXPECT_NOT_NULL(file->data->data);
+  memcpy(file->data->data, content, strlen(content));
+  file->data->size = strlen(content);
+
+  File* chunk_files[] = {file};
+  Chunk* chunk = chunk_create(chunk_files, 1);
+  EXPECT_NOT_NULL(chunk);
+
+  Data* serialized = chunk_serialize(chunk, false);
+  EXPECT_NOT_NULL(serialized);
+
+  Chunk* deserialized = chunk_deserialize(serialized, false);
+  EXPECT_NOT_NULL(deserialized);
+  EXPECT_EQ_INT(deserialized->element_count, 1);
+
+  chunk_destroy(deserialized);
+  data_destroy(serialized);
+  chunk_destroy(chunk);
+}
+
+/* Smoke test for compress/decompress fuzz target */
+static void test_fuzz_compress_decompress() {
+  /* Must use malloc'd buffers since data_destroy calls free(data->data) */
+  const char* test_data = "Hello, compression fuzzing!";
+  size_t len = strlen(test_data);
+  void* buf = malloc(len);
+  EXPECT_NOT_NULL(buf);
+  memcpy(buf, test_data, len);
+
+  Data* original = data_create(buf, len);
+  EXPECT_NOT_NULL(original);
+
+  Data* compressed = data_compress(original, 3);
+  EXPECT_NOT_NULL(compressed);
+
+  Data* decompressed = data_decompress(compressed);
+  EXPECT_NOT_NULL(decompressed);
+  EXPECT_EQ_INT((int)decompressed->size, (int)len);
+  EXPECT_EQ_INT(memcmp(decompressed->data, test_data, len), 0);
+
+  data_destroy(decompressed);
+  data_destroy(compressed);
+  data_destroy(original);
+}
+
+/* Smoke test for delta_deserialize fuzz target */
+static void test_fuzz_delta_deserialize() {
+  const char* old_data_str = "Hello, World!";
+  const char* new_data_str = "Hello, Delta!";
+  size_t old_len = strlen(old_data_str);
+  size_t new_len = strlen(new_data_str);
+
+  DeltaSignature* sig = delta_signature_create((void*)old_data_str, old_len, 64);
+  EXPECT_NOT_NULL(sig);
+
+  Delta* delta = delta_compute((void*)new_data_str, new_len, sig, 64);
+  EXPECT_NOT_NULL(delta);
+
+  Data* serialized = delta_serialize(delta);
+  EXPECT_NOT_NULL(serialized);
+
+  Delta* deserialized = delta_deserialize(serialized);
+  EXPECT_NOT_NULL(deserialized);
+
+  delta_destroy(deserialized);
+  data_destroy(serialized);
+  delta_destroy(delta);
+  delta_signature_destroy(sig);
+}
+
+/* Smoke test for metadata_from_buf fuzz target */
+static void test_fuzz_metadata_from_buf() {
+  EXPECT_TRUE(to_disk("fuzz_meta_test.txt", "metadata test", 13));
+
+  struct stat st;
+  EXPECT_EQ_INT(stat("fuzz_meta_test.txt", &st), 0);
+
+  FileMetadata* meta = file_metadata_create(&st);
+  EXPECT_NOT_NULL(meta);
+
+  size_t meta_buf_size = sizeof(int32_t) + FILE_METADATA_WIRE_SIZE;
+  char* meta_buf = malloc(meta_buf_size);
+  EXPECT_NOT_NULL(meta_buf);
+  char* meta_ptr = meta_buf;
+  metadata_to_buf(&meta_ptr, meta);
+
+  char* buf_copy = meta_buf;
+  FileMetadata* deserialized = metadata_from_buf(&buf_copy);
+  EXPECT_NOT_NULL(deserialized);
+  EXPECT_EQ_INT((int)deserialized->mode, (int)meta->mode);
+  EXPECT_EQ_INT((int)deserialized->mtime_sec, (int)meta->mtime_sec);
+
+  file_metadata_destroy(deserialized);
+  free(meta_buf);
+  file_metadata_destroy(meta);
+  unlink("fuzz_meta_test.txt");
+}
+
+/* Smoke test for delta_signature_deserialize fuzz target */
+static void test_fuzz_delta_signature_deserialize() {
+  const char* data_str = "Test data for signature";
+  size_t len = strlen(data_str);
+
+  DeltaSignature* sig = delta_signature_create((void*)data_str, len, 64);
+  EXPECT_NOT_NULL(sig);
+
+  Data* serialized = delta_signature_serialize(sig);
+  EXPECT_NOT_NULL(serialized);
+
+  DeltaSignature* deserialized = delta_signature_deserialize(serialized);
+  EXPECT_NOT_NULL(deserialized);
+  EXPECT_EQ_INT((int)deserialized->block_size, 64);
+
+  delta_signature_destroy(deserialized);
+  data_destroy(serialized);
+  delta_signature_destroy(sig);
+}
+
+/* Smoke test for glob_match fuzz target */
+static void test_fuzz_glob_match() {
+  EXPECT_TRUE(glob_match("*.txt", "file.txt"));
+  EXPECT_FALSE(glob_match("*.txt", "file.TXT"));
+  EXPECT_FALSE(glob_match("*.txt", "file.c"));
+  EXPECT_TRUE(glob_match("data?", "data1"));
+  EXPECT_TRUE(glob_match("data?", "dataX"));
+  EXPECT_FALSE(glob_match("data?", "data12"));
+  EXPECT_TRUE(glob_match("src/**/*.c", "src/main.c"));
+  EXPECT_TRUE(glob_match("**/test*.py", "src/tests/test_foo.py"));
+  EXPECT_FALSE(glob_match("*.md", "readme.txt"));
+}
+
+void test_fuzz_smoke() {
+  test_fuzz_chunk_deserialize();
+  test_fuzz_compress_decompress();
+  test_fuzz_delta_deserialize();
+  test_fuzz_metadata_from_buf();
+  test_fuzz_delta_signature_deserialize();
+  test_fuzz_glob_match();
+}

tests/test_fuzz_smoke.h

@@ -0,0 +1,6 @@
+#ifndef TEST_FUZZ_SMOKE_H
+#define TEST_FUZZ_SMOKE_H
+
+void test_fuzz_smoke();
+
+#endif

tests/test_multiprocessing.c

@@ -1,10 +1,18 @@
 #include "test_multiprocessing.h"
 #include "multiprocessing.h"
 #include "config.h"
+#include "protocol.h"
 #include "queue.h"
 #include "utils.h"
 #include "test_utils.h"
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
+#include <threads.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
 
 /* Test pipeline_context_sender_create/destroy with valid arguments */
 static void test_sender_create_destroy() {
@@ -92,10 +100,85 @@ static void test_receiver_fd_zero() {
   pipeline_context_receiver_destroy(ctx);
 }
 
+/* Test that receive_thread completes cleanly when sent FINISHED immediately */
+static void test_receive_thread_finished() {
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/src"), str_dup("/tmp/dst"),
+                              true, false, false, false, false, 0, false, 0);
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+
+    Queue* q = queue_create(5, file_destroy);
+    EXPECT_NOT_NULL(q);
+    PipelineContextReceiver* ctx = pipeline_context_receiver_create(cfg, q, p[0]);
+    EXPECT_NOT_NULL(ctx);
+
+    int ret = receive_thread(ctx);
+
+    pipeline_context_receiver_destroy(ctx);
+    close(p[0]);
+    _exit(ret == thrd_success ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+
+    send_status(p[1], STATUS_FINISHED);
+
+    int status;
+    waitpid(pid, &status, 0);
+    close(p[1]);
+    config_delete(cfg);
+
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+/* Test that write_thread completes when queue signals done */
+static void test_write_thread_done() {
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/src"), str_dup("/tmp/dst"),
+                              false, false, false, false, false, 0, false, 0);
+
+  Queue* q = queue_create(5, file_destroy);
+  EXPECT_NOT_NULL(q);
+
+  PipelineContextReceiver* ctx = pipeline_context_receiver_create(cfg, q, 0);
+  EXPECT_NOT_NULL(ctx);
+
+  /* Mark as done so write_thread exits immediately */
+  ctx->receiver_done = true;
+
+  thrd_t writer;
+  int ret = thrd_create(&writer, write_thread, ctx);
+  EXPECT_EQ_INT(ret, thrd_success);
+
+  int result;
+  thrd_join(writer, &result);
+  EXPECT_EQ_INT(result, thrd_success);
+
+  /* Clean up manually (pipeline_context_receiver_destroy would double-free) */
+  mtx_destroy(&ctx->mutex);
+  cnd_destroy(&ctx->condition_not_full);
+  cnd_destroy(&ctx->condition_not_empty);
+  free(ctx);
+  queue_destroy(q);
+  config_delete(cfg);
+}
+
 void test_multiprocessing() {
   test_sender_create_destroy();
   test_receiver_create_destroy();
   test_sender_queue_capacities();
   test_sender_zero_capacity();
   test_receiver_fd_zero();
+  if (!is_running_under_valgrind()) {
+    test_receive_thread_finished();
+  }
+  test_write_thread_done();
 }

tests/test_server.c

@@ -0,0 +1,151 @@
+#include "test_server.h"
+#include "config.h"
+#include "file.h"
+#include "protocol.h"
+#include "test_utils.h"
+#include "utils.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+/* Include server.c but rename main to avoid conflict with test runner's main */
+#define main server_main_
+#include "server.c"
+#undef main
+
+/* Test receive_files with immediate FINISHED status */
+static void test_receive_files_finished() {
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/src"), str_dup("/tmp/dst"),
+                              false, false, false, false, false, 0, false, 0);
+  EXPECT_NOT_NULL(cfg);
+
+  /* Use socketpair for full-duplex communication */
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    /* Child: run receive_files - needs both directions */
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    int ret = receive_files(cfg, p[0]);
+    close(p[0]);
+    config_delete(cfg);
+    _exit(ret == 0 ? 0 : 1);
+  } else {
+    /* Parent: send FINISHED */
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+    send_status(p[1], STATUS_FINISHED);
+    Status resp;
+    receive_status(p[1], &resp);
+
+    int status;
+    waitpid(pid, &status, 0);
+    close(p[1]);
+    config_delete(cfg);
+
+    EXPECT_EQ_INT(resp, STATUS_OK);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+/* Test receive_files with STATUS_NEXT + file data */
+static void test_receive_files_single_file() {
+  const char* content = "Hello from server test!";
+  size_t len = strlen(content);
+
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/src"), str_dup("/tmp/dst"),
+                              false, false, false, false, false, 0, false, 0);
+  EXPECT_NOT_NULL(cfg);
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    int ret = receive_files(cfg, p[0]);
+    close(p[0]);
+    config_delete(cfg);
+    _exit(ret == 0 ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+
+    send_status(p[1], STATUS_NEXT);
+
+    File* file = file_create("test_server_file.txt");
+    EXPECT_NOT_NULL(file);
+    file->data->data = malloc(len);
+    EXPECT_NOT_NULL(file->data->data);
+    memcpy(file->data->data, content, len);
+    file->data->size = len;
+
+    send_str(p[1], file->path);
+    send_data(p[1], file->data);
+    file_destroy(file);
+
+    send_status(p[1], STATUS_FINISHED);
+    Status resp;
+    receive_status(p[1], &resp);
+
+    int status;
+    waitpid(pid, &status, 0);
+    close(p[1]);
+    config_delete(cfg);
+
+    EXPECT_EQ_INT(resp, STATUS_OK);
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+/* Test receive_files with STATUS_ABORT */
+static void test_receive_files_abort() {
+  Config* cfg = config_create(str_dup(PROTOCOL_VERSION), str_dup("/src"), str_dup("/tmp/dst"),
+                              false, false, false, false, false, 0, false, 0);
+  EXPECT_NOT_NULL(cfg);
+
+  int p[2];
+  EXPECT_EQ_INT(socketpair(AF_UNIX, SOCK_STREAM, 0, p), 0);
+  io_set_fds(p[0], p[1]);
+  io_set_bwlimit(0);
+
+  pid_t pid = fork();
+  if (pid == 0) {
+    close(p[1]);
+    io_set_fds(p[0], p[0]);
+    int ret = receive_files(cfg, p[0]);
+    close(p[0]);
+    config_delete(cfg);
+    _exit(ret == -1 ? 0 : 1);
+  } else {
+    close(p[0]);
+    io_set_fds(p[1], p[1]);
+    send_status(p[1], STATUS_ABORT);
+
+    int status;
+    waitpid(pid, &status, 0);
+    close(p[1]);
+    config_delete(cfg);
+
+    EXPECT_TRUE(WIFEXITED(status) && WEXITSTATUS(status) == 0);
+  }
+}
+
+void test_server() {
+  if (!is_running_under_valgrind()) {
+    test_receive_files_finished();
+    test_receive_files_single_file();
+    test_receive_files_abort();
+  }
+}

tests/test_server.h

@@ -0,0 +1,6 @@
+#ifndef TEST_SERVER_H
+#define TEST_SERVER_H
+
+void test_server();
+
+#endif

tests/test_transport_tcp.c

@@ -1,6 +1,8 @@
 #include "test_transport_tcp.h"
+#include "protocol.h"
 #include "test_utils.h"
 #include "transport_tcp.h"
+#include <string.h>
 #include <unistd.h>
 
 static void test_server_create_ephemeral() {
@@ -35,9 +37,49 @@ static void test_client_delete_null() {
   client_delete(c);
 }
 
+/* Test tcp_set_timeouts with valid values */
+static void test_tcp_set_timeouts() {
+  tcp_set_timeouts(0, 0);
+  tcp_set_timeouts(60, 20);
+  tcp_set_timeouts(-1, -1);
+  EXPECT_TRUE(true);
+}
+
+/* Test client_connect with an invalid host (should fail gracefully) */
+static void test_client_connect_invalid_host() {
+  Client* c = client_create();
+  EXPECT_NOT_NULL(c);
+  bool ok = client_connect(c, "10.255.255.1", 9999);
+  EXPECT_FALSE(ok);
+  client_disconnect(c);
+  client_delete(c);
+}
+
+/* Test server_delete with double-delete safety */
+static void test_server_delete_double() {
+  Server* s = server_create(0);
+  EXPECT_NOT_NULL(s);
+  server_delete(&s);
+  EXPECT_NULL(s);
+  server_delete(&s);
+  EXPECT_NULL(s);
+}
+
+/* Test client_disconnect then client_delete */
+static void test_client_disconnect_delete() {
+  Client* c = client_create();
+  EXPECT_NOT_NULL(c);
+  client_disconnect(c);
+  client_delete(c);
+}
+
 void test_transport_tcp() {
   test_server_create_ephemeral();
   test_server_delete_null();
   test_client_create();
   test_client_delete_null();
+  test_tcp_set_timeouts();
+  test_client_connect_invalid_host();
+  test_server_delete_double();
+  test_client_disconnect_delete();
 }

tests/test_transport_tls.c

@@ -1,7 +1,10 @@
 #include "test_transport_tls.h"
+#include "protocol.h"
 #include "test_utils.h"
 #include "transport_tcp.h"
 #include "transport_tls.h"
+#include <string.h>
+#include <unistd.h>
 
 static void test_tls_global_init() {
   bool ok = tls_global_init();
@@ -18,7 +21,30 @@ static void test_server_create_tls_without_certs() {
   EXPECT_NULL(s);
 }
 
+/* Test client_connect_tls with no server listening (should fail gracefully) */
+static void test_client_connect_tls_fail() {
+  Client* c = client_create();
+  EXPECT_NOT_NULL(c);
+  bool ok = client_connect_tls(c, "127.0.0.1", 1, NULL, NULL, NULL);
+  EXPECT_FALSE(ok);
+  client_disconnect(c);
+  client_delete(c);
+}
+
+/* Test server_create_tls with empty cert paths (should fail gracefully) */
+static void test_server_create_tls_empty_certs() {
+  Server* s = server_create(0);
+  EXPECT_NOT_NULL(s);
+  bool ok = server_create_tls(s, "", "", NULL);
+  EXPECT_FALSE(ok);
+  EXPECT_NULL(s->ssl_ctx);
+  server_delete(&s);
+  EXPECT_NULL(s);
+}
+
 void test_transport_tls() {
   test_tls_global_init();
   test_server_create_tls_without_certs();
+  test_client_connect_tls_fail();
+  test_server_create_tls_empty_certs();
 }