Index: lib/sanitizer_common/sanitizer_common_interceptors.inc
===================================================================
--- lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -7348,6 +7348,30 @@
 #define INIT_SETVBUF
 #endif
 
+#if SANITIZER_INTERCEPT_FPARSELN
+INTERCEPTOR(char *, fparseln, __sanitizer_FILE *stream, SIZE_T *len,
+            SIZE_T *lineno, const char delim[3], int flags) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, fparseln, stream, len, lineno, delim, flags);
+  if (lineno)
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, lineno, sizeof(*lineno));
+  if (delim)
+    COMMON_INTERCEPTOR_READ_RANGE(ctx, delim, sizeof(delim[0]) * 3);
+  char *ret = REAL(fparseln)(stream, len, lineno, delim, flags);
+  if (ret) {
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, ret, REAL(strlen)(ret) + 1);
+    if (len)
+      COMMON_INTERCEPTOR_WRITE_RANGE(ctx, len, sizeof(*len));
+    if (lineno)
+      COMMON_INTERCEPTOR_WRITE_RANGE(ctx, lineno, sizeof(*lineno));
+  }
+  return ret;
+}
+#define INIT_FPARSELN COMMON_INTERCEPT_FUNCTION(fparseln)
+#else
+#define INIT_FPARSELN
+#endif
+
 static void InitializeCommonInterceptors() {
   static u64 metadata_mem[sizeof(MetadataHashMap) / sizeof(u64) + 1];
   interceptor_metadata_map = new((void *)&metadata_mem) MetadataHashMap();
@@ -7604,6 +7628,7 @@
   INIT_GETMNTINFO;
   INIT_MI_VECTOR_HASH;
   INIT_SETVBUF;
+  INIT_FPARSELN;
 
   INIT___PRINTF_CHK;
 }
Index: lib/sanitizer_common/sanitizer_platform_interceptors.h
===================================================================
--- lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -520,5 +520,6 @@
   SI_LINUX || SI_MAC)
 #define SANITIZER_INTERCEPT_GETMNTINFO SI_NETBSD
 #define SANITIZER_INTERCEPT_MI_VECTOR_HASH SI_NETBSD
+#define SANITIZER_INTERCEPT_FPARSELN SI_NETBSD
 
 #endif  // #ifndef SANITIZER_PLATFORM_INTERCEPTORS_H
Index: test/sanitizer_common/TestCases/NetBSD/fparseln.cc
===================================================================
--- /dev/null
+++ test/sanitizer_common/TestCases/NetBSD/fparseln.cc
@@ -0,0 +1,25 @@
+// RUN: %clangxx -O0 -g %s -o %t && %run %t 2>&1 | FileCheck %s
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) {
+  printf("fparseln\n");
+
+  FILE *fp = fopen("/etc/fstab", "r");
+  assert(fp);
+
+  int flags = FPARSELN_UNESCALL;
+  const char *delim = "\\\\#";
+  size_t lineno = 0, len;
+  char *line;
+  while ((line = fparseln(fp, &len, &lineno, delim, flags))) {
+    printf("lineno: %zu, length: %zu, line: %s\n", lineno, len, line);
+    free(line);
+  }
+
+  // CHECK: fparseln
+
+  return 0;
+}