From: Ian Jackson <ijackson@chiark.greenend.org.uk>
Date: Fri, 11 Sep 2026 11:17:37 +0000 (+0100)
Subject: Report to stderr if we can't use getentropy
X-Git-Tag: adns-1.7.0~8
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=commitdiff_plain;h=838cef86ec44b12b6c35b50317bcc5e99c7c4765;p=adns.git

Report to stderr if we can't use getentropy
---

diff --git a/regress/m1test b/regress/m1test
index 37fab25..58bae06 100755
--- a/regress/m1test
+++ b/regress/m1test
@@ -62,6 +62,9 @@ fi
 queryargs="$*"
 
 initstring="`cat $srcdir/init-$initfile.text`"
+initstring="$initstring
+options adns_qid_predictable_ok
+"
 xinitflagsf=$srcdir/$program-xinitflags.text
 if test -e $xinitflagsf
 then
diff --git a/regress/shlib b/regress/shlib
index eabe631..7ede3fd 100644
--- a/regress/shlib
+++ b/regress/shlib
@@ -16,6 +16,9 @@ playback_prepare () {
 	read <&4 queryargs
 
 	initstring="`cat $srcdir/init-$initfile.text`"
+        initstring="$initstring
+options adns_qid_predictable_ok
+"
 	xinitflagsf=$srcdir/$program-xinitflags.text
 	if test -e $xinitflagsf
 	then
diff --git a/src/adns.h b/src/adns.h
index e8e108d..ed3c955 100644
--- a/src/adns.h
+++ b/src/adns.h
@@ -600,6 +600,10 @@ int adns_init_logfn(adns_state *newstate_r, adns_initflags flags,
  *   control the relative order of addresses in answers.  This option
  *   overrides the corresponding init flags (covered by adns_if_afmask).
  *
+ *  adns_qid_predictable_ok
+ *   Do not print an error message to stderr if we cannot use getentropy()
+ *   to generate random query-ids.  In this case, 
+ *
  *  adns_ignoreunkcfg
  *   Ignore unknown options and configuration directives, rather than
  *   logging them.  To be effective, appear in the configuration
diff --git a/src/internal.h b/src/internal.h
index 90e63d6..1c4976d 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -407,6 +407,7 @@ struct adns__state {
   } sortlist[MAXSORTLIST];
   char **searchlist;
   unsigned config_report_unknown:1;
+  unsigned nextid_report_fallback:1;
   unsigned short rand48xsubi[3];
 };
 
diff --git a/src/nextid.c b/src/nextid.c
index d30eabc..c33e175 100644
--- a/src/nextid.c
+++ b/src/nextid.c
@@ -22,6 +22,24 @@
 
 #include "internal.h"
 
+/* common, error handling */
+
+static void good_failure(adns_state ads, const char *fmt, ...)
+  PRINTFFORMAT(2,3);
+
+static void good_failure(adns_state ads, const char *fmt, ...) {
+  va_list al;
+
+  if (!ads->nextid_report_fallback) return;
+  ads->nextid_report_fallback= 0;
+
+  va_start(al,fmt);
+  adns__vdiag(ads,
+	      " warning (suppress with 'options adns_qid_predictable_ok')",
+	      adns_if_noerrprint, -1,0, fmt, al);
+  va_end(al);
+}
+
 #ifdef HAVE_GETENTROPY
 
 /* use getentropy */
@@ -36,7 +54,7 @@ static int32_t good_nextid(adns_state ads) {
   if (!ads->nextid.full) {
     r= getentropy(ads->nextid.buf, sizeof(ads->nextid.buf));
     if (r) {
-      // XXXX log a warning
+      good_failure(ads, "getentropy() failed: %s", strerror(errno));
       return -1;
     }
     ads->nextid.full= NEXTID_RANDOM_BUF_COUNT;
@@ -52,7 +70,7 @@ static int32_t good_nextid(adns_state ads) {
 static void good_init(struct nextid_state *state) { }
 
 static int32_t good_nextid(adns_state ads) {
-  // XXXX log a warning
+  good_failure(ads, "getentropy() not available on this operating system");
   return -1;
 }
 
diff --git a/src/setup.c b/src/setup.c
index dd72eac..02ce6df 100644
--- a/src/setup.c
+++ b/src/setup.c
@@ -335,6 +335,10 @@ static void ccf_options(adns_state ads, const char *fn,
       ads->config_report_unknown=0;
       continue;
     }
+    if (WORD_IS("adns_qid_predictable_ok")) {
+      ads->nextid_report_fallback= 0;
+      continue;
+    }
     if (/* adns's query strategy is not configurable */
 	WORD_STARTS("timeout:") ||
 	WORD_STARTS("attempts:") ||
@@ -639,6 +643,7 @@ static int init_begin(adns_state *ads_r, adns_initflags flags,
   timerclear(&ads->tcptimeout);
   ads->searchlist= 0;
   ads->config_report_unknown=1;
+  ads->nextid_report_fallback=1;
 
   pid= getpid();
   ads->rand48xsubi[0]= pid;