refactor: drop dead filter_rules_apply, unify set_error, dedup path_is_within

src/server/server.c

@@ -226,11 +226,6 @@ static void release_authorization(void) {
     close(root_fd);
 }
 
-static bool path_is_within(const char* root, const char* path) {
-  size_t n = strlen(root);
-  return strncmp(root, path, n) == 0 && (path[n] == '\0' || path[n] == '/');
-}
-
 /* --mkpath contract: when the client's destination root directory does not
    exist yet on the server side, --mkpath tells the server to create it (and
    any missing leading components) below the authorized root at connection
@@ -790,7 +785,7 @@ void handler(int file_descriptor) {
   if (joined_destination)
     destination = joined_destination;
   if (!destination || has_path_traversal(destination) ||
-      !path_is_within(authorized_root, destination)) {
+      !path_is_within_root(authorized_root, destination)) {
     log_message(LOG_LEVEL_ERROR, "Rejected destination outside authorized root");
     free(joined_destination);
     joined_destination = NULL;

src/server/server_cli.c

@@ -3,20 +3,12 @@
 #include "credentials.h"
 #include "utils.h"
 #include <limits.h>
-#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/socket.h>
 
-static void set_error(char* err, size_t err_size, const char* fmt, ...) {
-  if (!err || err_size == 0)
-    return;
-  va_list args;
-  va_start(args, fmt);
-  vsnprintf(err, err_size, fmt, args);
-  va_end(args);
-}
+#define set_error utils_set_error
 
 void server_cli_options_default(ServerCliOptions* opts) {
   if (!opts)

src/shared/credentials.c

@@ -8,7 +8,6 @@
 #include <openssl/evp.h>
 #include <openssl/params.h>
 #include <openssl/rand.h>
-#include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -58,14 +57,7 @@ struct CredentialStore {
 static const uint8_t k_dummy_stored_key[CREDENTIAL_KEY_LEN] = {0};
 static const uint8_t k_dummy_server_key[CREDENTIAL_KEY_LEN] = {0};
 
-static void set_error(char* err, size_t err_size, const char* fmt, ...) {
-  if (!err || err_size == 0)
-    return;
-  va_list args;
-  va_start(args, fmt);
-  vsnprintf(err, err_size, fmt, args);
-  va_end(args);
-}
+#define set_error utils_set_error
 
 static bool is_comment_char(char c) {
   return c == '#' || c == ';';

src/shared/daemon_conf.c

@@ -6,7 +6,6 @@
 #include <errno.h>
 #include <limits.h>
 #include <netinet/in.h>
-#include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -17,14 +16,7 @@
 /* helpers                                                             */
 /* ------------------------------------------------------------------ */
 
-static void set_error(char* err, size_t err_size, const char* fmt, ...) {
-  if (!err || err_size == 0)
-    return;
-  va_list args;
-  va_start(args, fmt);
-  vsnprintf(err, err_size, fmt, args);
-  va_end(args);
-}
+#define set_error utils_set_error
 
 /* Trim leading and trailing ASCII space/tab in place; returns the new start. */
 static char* trim_ws(char* s) {

src/shared/filter.c

@@ -4,22 +4,12 @@
 #include <ctype.h>
 #include <errno.h>
 #include <limits.h>
-#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
-/* Write a diagnostic message into the caller's optional buffer.  A NULL `err`
- * (or a zero size) is a no-op, so a caller that only needs the boolean status
- * may pass NULL without the snprintf-on-NULL undefined behaviour. */
-static void filter_set_error(char* err, size_t err_size, const char* fmt, ...) {
-  if (!err || err_size == 0)
-    return;
-  va_list ap;
-  va_start(ap, fmt);
-  vsnprintf(err, err_size, fmt, ap);
-  va_end(ap);
-}
+/* Write a diagnostic message into the caller's optional buffer. */
+#define filter_set_error utils_set_error
 
 /* ---- Ordered rule lists ---- */
 
@@ -870,8 +860,3 @@ FilterAction filter_rules_apply_side(const FilterRuleList* list, const char* rel
   }
   return FILTER_ACTION_NONE;
 }
-
-FilterAction filter_rules_apply(const FilterRuleList* list, const char* rel_path, const char* leaf,
-                                bool is_dir) {
-  return filter_rules_apply_side(list, rel_path, leaf, is_dir, FILTER_SIDE_SENDER);
-}

src/shared/filter.h

@@ -131,9 +131,4 @@ FilterRuleList* filter_file_read(const char* dir_path, const char* owner_rel, bo
 FilterAction filter_rules_apply_side(const FilterRuleList* list, const char* rel_path,
                                      const char* leaf, bool is_dir, unsigned side);
 
-/* Sender-side convenience wrapper (kept for callers/tests that only need the
- * transfer decision). */
-FilterAction filter_rules_apply(const FilterRuleList* list, const char* rel_path, const char* leaf,
-                                bool is_dir);
-
 #endif

src/shared/utils.c

@@ -7,6 +7,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <netinet/in.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -48,6 +49,15 @@ const char* utils_get_authorized_root_path(void) {
   return authorized_root_path;
 }
 
+void utils_set_error(char* err, size_t err_size, const char* fmt, ...) {
+  if (!err || err_size == 0)
+    return;
+  va_list args;
+  va_start(args, fmt);
+  vsnprintf(err, err_size, fmt, args);
+  va_end(args);
+}
+
 bool path_is_within_root(const char* root, const char* path) {
   size_t root_len = strlen(root);
   return strncmp(root, path, root_len) == 0 && (path[root_len] == '\0' || path[root_len] == '/');

src/shared/utils.h

@@ -225,6 +225,11 @@ void utils_set_authorized_root_fd(int fd);
  * threads spawn; see utils.c). */
 int utils_get_authorized_root_fd(void);
 const char* utils_get_authorized_root_path(void);
+/* Write a diagnostic message into a caller-supplied buffer, mirroring
+ * vsnprintf.  A NULL `err` or a zero `err_size` is a no-op, so a caller that
+ * only needs the boolean status may safely pass NULL.  Returns nothing; the
+ * buffer is always NUL-terminated by vsnprintf when err_size > 0. */
+void utils_set_error(char* err, size_t err_size, const char* fmt, ...);
 /* True when `path` is `root` itself or lies directly beneath it: a lexical
  * prefix test requiring the byte after `root` to be '\0' or '/'.  Both `root`
  * and `path` must be absolute canonical paths free of "."/".." components (the

tests/test_filter.c

@@ -179,8 +179,10 @@ static void test_filter_rules_apply_supported_modifiers() {
     const char* texts[] = {"- *.tmp"};
     FilterRuleList* list = filter_base_build(texts, 1, false, false, NULL, 0);
     EXPECT_NOT_NULL(list);
-    EXPECT_EQ_INT(filter_rules_apply(list, "b.tmp", "b.tmp", false), FILTER_ACTION_EXCLUDE);
-    EXPECT_EQ_INT(filter_rules_apply(list, "a.txt", "a.txt", false), FILTER_ACTION_NONE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "b.tmp", "b.tmp", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_EXCLUDE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "a.txt", "a.txt", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_NONE);
     filter_rule_list_free(list);
   }
   /* anchored include then exclude-all */
@@ -188,8 +190,10 @@ static void test_filter_rules_apply_supported_modifiers() {
     const char* texts[] = {"+ /a.txt", "- *"};
     FilterRuleList* list = filter_base_build(texts, 2, false, false, NULL, 0);
     EXPECT_NOT_NULL(list);
-    EXPECT_EQ_INT(filter_rules_apply(list, "a.txt", "a.txt", false), FILTER_ACTION_INCLUDE);
-    EXPECT_EQ_INT(filter_rules_apply(list, "b.txt", "b.txt", false), FILTER_ACTION_EXCLUDE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "a.txt", "a.txt", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_INCLUDE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "b.txt", "b.txt", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_EXCLUDE);
     filter_rule_list_free(list);
   }
   /* negate */
@@ -197,8 +201,10 @@ static void test_filter_rules_apply_supported_modifiers() {
     const char* texts[] = {"-! *.o"};
     FilterRuleList* list = filter_base_build(texts, 1, false, false, NULL, 0);
     EXPECT_NOT_NULL(list);
-    EXPECT_EQ_INT(filter_rules_apply(list, "foo.c", "foo.c", false), FILTER_ACTION_EXCLUDE);
-    EXPECT_EQ_INT(filter_rules_apply(list, "foo.o", "foo.o", false), FILTER_ACTION_NONE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "foo.c", "foo.c", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_EXCLUDE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "foo.o", "foo.o", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_NONE);
     filter_rule_list_free(list);
   }
   /* dir-only trailing slash */
@@ -206,8 +212,10 @@ static void test_filter_rules_apply_supported_modifiers() {
     const char* texts[] = {"+ dir/", "- *"};
     FilterRuleList* list = filter_base_build(texts, 2, false, false, NULL, 0);
     EXPECT_NOT_NULL(list);
-    EXPECT_EQ_INT(filter_rules_apply(list, "dir", "dir", true), FILTER_ACTION_INCLUDE);
-    EXPECT_EQ_INT(filter_rules_apply(list, "dir", "dir", false), FILTER_ACTION_EXCLUDE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "dir", "dir", true, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_INCLUDE);
+    EXPECT_EQ_INT(filter_rules_apply_side(list, "dir", "dir", false, FILTER_SIDE_SENDER),
+                  FILTER_ACTION_EXCLUDE);
     filter_rule_list_free(list);
   }
 }