Use pathconf(), also check NAME_MAX

Author: andy5995

src/utils.c

@@ -495,6 +495,90 @@ count_chars(const char c, const char *str)
 }
 
 
+int
+validate_path(const char *path)
+{
+  if (!path)
+  {
+    fprintf(stderr, "Error: Path is NULL.\n");
+    return -1;                  // Invalid input
+  }
+
+  // Query dynamic limits
+  long path_max = pathconf("/", _PC_PATH_MAX);
+  if (path_max == -1)
+  {
+    if (errno == 0)
+    {
+      path_max = PATH_MAX;      // Use fallback if no limit
+    }
+    else
+    {
+      perror("pathconf for PATH_MAX");
+      return -1;
+    }
+  }
+
+  long name_max = pathconf("/", _PC_NAME_MAX);
+  if (name_max == -1)
+  {
+    if (errno == 0)
+    {
+      name_max = NAME_MAX;      // Use fallback if no limit
+    }
+    else
+    {
+      perror("pathconf for NAME_MAX");
+      return -1;
+    }
+  }
+
+  size_t path_len = strlen(path);
+  if (path_len > (size_t) path_max)
+  {
+    fprintf(stderr, "Error: Path length (%zu) exceeds PATH_MAX (%ld).\n",
+            path_len, path_max);
+    return -1;
+  }
+
+  // Check individual component lengths
+  const char *start = path;
+  while (*start)
+  {
+    const char *end = strchr(start, '/');
+    size_t component_len = end ? (size_t) (end - start) : strlen(start);
+
+    if (component_len > (size_t) name_max)
+    {
+      fprintf(stderr,
+              "Error: Path component '%.*s' exceeds NAME_MAX (%ld).\n",
+              (int) component_len, start, name_max);
+      return -1;
+    }
+
+    if (!end)
+    {
+      break;
+    }
+    start = end + 1;
+  }
+
+  return 0;
+}
+
+//int main() {
+    //const char *test_path = "/home/user/documents/very_long_filename.txt";
+
+    //if (validate_path(test_path) == 0) {
+        //printf("The path '%s' is valid.\n", test_path);
+    //} else {
+        //printf("The path '%s' is invalid.\n", test_path);
+    //}
+
+    //return 0;
+//}
+
+
 ///////////////////////////////////////////////////////////////////////
 #ifdef TEST_LIB
 
@@ -723,6 +807,15 @@ test_count_chars(void)
   return;
 }
 
+void
+test_validate_path(void)
+{
+  assert(validate_path
+         ("/dddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd/foo")
+         != 0);
+  return;
+}
+
 
 int
 main()
@@ -756,6 +849,8 @@ main()
   free(escaped_path);
 
   test_count_chars();
+
+  test_validate_path();
   return 0;
 }
 #endif

src/utils.h

@@ -64,4 +64,6 @@ bool is_dir_f(const char *pathname);
 
 int count_chars(const char c, const char *str);
 
+int validate_path(const char *path);
+
 #endif