[sanitizer] Add dn_comp interceptor

[kda]

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

2538

nit: alphabetize the interceptors, as you alphabetized the def (... DN_COMP_EXPAND).
likewise in all cases below.

[vitalybuka]

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

2538

Sorry, I am not sure what are you asking to do.

[kda]

The define is COMP then EXPAND.

How about making all the code have 'comp' first and then 'expand' second.

[vitalybuka]

alphabetized

[kda]

thanks

[aaronpuchert]

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

2569

What about this comment, now that the intercept has been added?

compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc

 }
 #define INIT___B64_TO                      \
     COMMON_INTERCEPT_FUNCTION(__b64_ntop); \
     COMMON_INTERCEPT_FUNCTION(__b64_pton);
 #else  // SANITIZER_INTERCEPT___B64_TO
 #define INIT___B64_TO
 #endif  // SANITIZER_INTERCEPT___B64_TO
 
-#if SANITIZER_INTERCEPT___DN_EXPAND
+#if SANITIZER_INTERCEPT_DN_COMP_EXPAND
 #  if __GLIBC_PREREQ(2, 34)
 // Changed with https://sourceware.org/git/?p=glibc.git;h=640bbdf
+#    define DN_COMP_INTERCEPTOR_NAME dn_comp
 #    define DN_EXPAND_INTERCEPTOR_NAME dn_expand
 #  else
+#    define DN_COMP_INTERCEPTOR_NAME __dn_comp
 #    define DN_EXPAND_INTERCEPTOR_NAME __dn_expand
 #  endif
+INTERCEPTOR(int, DN_COMP_INTERCEPTOR_NAME, unsigned char *exp_dn,
+            unsigned char *comp_dn, int length, unsigned char **dnptrs,
+            unsigned char **lastdnptr) {
+  void *ctx;
+  COMMON_INTERCEPTOR_ENTER(ctx, DN_COMP_INTERCEPTOR_NAME, exp_dn, comp_dn,
+                           length, dnptrs, lastdnptr);
+  int res = REAL(DN_COMP_INTERCEPTOR_NAME)(exp_dn, comp_dn, length, dnptrs,
+                                           lastdnptr);
+  if (res >= 0) {
+    COMMON_INTERCEPTOR_WRITE_RANGE(ctx, comp_dn, res);
+    if (dnptrs && lastdnptr) {
+      unsigned char **p = dnptrs;
+      for (; p != lastdnptr && *p; ++p)
+        ;
+      if (p != lastdnptr)
+        ++p;
+      COMMON_INTERCEPTOR_WRITE_RANGE(ctx, dnptrs, (p - dnptrs) * sizeof(*p));
+    }
+  }
+  return res;
+}
 INTERCEPTOR(int, DN_EXPAND_INTERCEPTOR_NAME, unsigned char const *base,
             unsigned char const *end, unsigned char const *src, char *dest,
             int space) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, DN_EXPAND_INTERCEPTOR_NAME, base, end, src,
                            dest, space);
   // TODO: add read check if __dn_comp intercept added
   int res = REAL(DN_EXPAND_INTERCEPTOR_NAME)(base, end, src, dest, space);
   if (res >= 0)
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, dest, internal_strlen(dest) + 1);
   return res;
 }
-#  define INIT___DN_EXPAND \
+#  define INIT_DN_COMP_EXPAND                            \
+    COMMON_INTERCEPT_FUNCTION(DN_COMP_INTERCEPTOR_NAME); \
     COMMON_INTERCEPT_FUNCTION(DN_EXPAND_INTERCEPTOR_NAME);
-#else  // SANITIZER_INTERCEPT___DN_EXPAND
-#  define INIT___DN_EXPAND
-#endif  // SANITIZER_INTERCEPT___DN_EXPAND
+#else  // SANITIZER_INTERCEPT_DN_COMP_EXPAND
+#  define INIT_DN_COMP_EXPAND
+#endif  // SANITIZER_INTERCEPT_DN_COMP_EXPAND
 
 #if SANITIZER_INTERCEPT_POSIX_SPAWN
 
 template <class RealSpawnPtr>
 static int PosixSpawnImpl(void *ctx, RealSpawnPtr *real_posix_spawn, pid_t *pid,
                           const char *file_or_path, const void *file_actions,
                           const void *attrp, char *const argv[],
                           char *const envp[]) {
#endif
   INIT_SETPWENT;
   INIT_CLOCK_GETTIME;
   INIT_CLOCK_GETCPUCLOCKID;
   INIT_GETITIMER;
   INIT_TIME;
   INIT_GLOB;
   INIT_GLOB64;
   INIT___B64_TO;
-  INIT___DN_EXPAND;
+  INIT_DN_COMP_EXPAND;
   INIT_POSIX_SPAWN;
   INIT_WAIT;
   INIT_WAIT4;
   INIT_INET;
   INIT_PTHREAD_GETSCHEDPARAM;
   INIT_GETADDRINFO;
   INIT_GETNAMEINFO;
   INIT_GETSOCKNAME;

compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h

#define SANITIZER_INTERCEPT_CLOCK_GETTIME \
   (SI_FREEBSD || SI_NETBSD || SI_LINUX || SI_SOLARIS)
 #define SANITIZER_INTERCEPT_CLOCK_GETCPUCLOCKID \
   (SI_LINUX || SI_FREEBSD || SI_NETBSD)
 #define SANITIZER_INTERCEPT_GETITIMER SI_POSIX
 #define SANITIZER_INTERCEPT_TIME SI_POSIX
 #define SANITIZER_INTERCEPT_GLOB (SI_GLIBC || SI_SOLARIS)
 #define SANITIZER_INTERCEPT_GLOB64 SI_GLIBC
 #define SANITIZER_INTERCEPT___B64_TO SI_LINUX_NOT_ANDROID
-#define SANITIZER_INTERCEPT___DN_EXPAND SI_LINUX_NOT_ANDROID
+#define SANITIZER_INTERCEPT_DN_COMP_EXPAND SI_LINUX_NOT_ANDROID
 #define SANITIZER_INTERCEPT_POSIX_SPAWN SI_POSIX
 #define SANITIZER_INTERCEPT_WAIT SI_POSIX
 #define SANITIZER_INTERCEPT_INET SI_POSIX
 #define SANITIZER_INTERCEPT_PTHREAD_GETSCHEDPARAM SI_POSIX
 #define SANITIZER_INTERCEPT_GETADDRINFO SI_POSIX
 #define SANITIZER_INTERCEPT_GETNAMEINFO SI_POSIX
 #define SANITIZER_INTERCEPT_GETSOCKNAME SI_POSIX
 #define SANITIZER_INTERCEPT_GETHOSTBYNAME SI_POSIX

compiler-rt/test/sanitizer_common/TestCases/Linux/dn_expand.cpp

void testComp() {
   pb[0] = msg;
   pb[1] = nullptr;
   mb += 64;
   char unsigned **pe = (char unsigned **)mb;
 
   char unsigned *n1 = mb;
   int res = dn_comp("llvm.org", mb, me - mb, pb, pe);
   assert(res == 10);
+  check_mem_is_good(mb, res);
+  // pb is [msg, llvm.org, nullptr]
+  check_mem_is_good(pb, sizeof(*pb) * 3);
   mb += res;
 
   char unsigned *n2 = mb;
   res = dn_comp("lab.llvm.org", mb, me - mb, pb, pe);
   assert(res == 6);
+  check_mem_is_good(mb, res);
+  // pb is [msg, llvm.org, lab.llvm.org, nullptr]
+  check_mem_is_good(pb, sizeof(*pb) * 4);
   mb += res;
 
   {
     char output[1024];
     res = dn_expand(msg, msg + sizeof(msg), n1, output, sizeof(output));
 
     fprintf(stderr, "%d\n", res);
     assert(res == 10);