From c8c1cab2b6a2754acbe7ee130c356383d0289f09 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Thu, 3 Apr 2025 03:57:42 +0000
Subject:  Deprioritize getexecname(), it's bad

Signed-off-by: Laurent Bercot <ska@appnovation.com>
---
 src/libstddjb/sagetexecname.c | 36 ++++++++++++++++++------------------
 src/sysdeps/trygetexecname.c  |  4 ++++
 2 files changed, 22 insertions(+), 18 deletions(-)

(limited to 'src')

diff --git a/src/libstddjb/sagetexecname.c b/src/libstddjb/sagetexecname.c
index 5ca4ba3..658df1a 100644
--- a/src/libstddjb/sagetexecname.c
+++ b/src/libstddjb/sagetexecname.c
@@ -2,7 +2,7 @@
 
 #include <skalibs/sysdeps.h>
 
-#if defined(SKALIBS_PROCSELFEXE)
+#if defined(SKALIBS_PROCSELFEXE)  /* Linux, midipix, Solaris */
 
 #include <skalibs/stralloc.h>
 #include <skalibs/djbunix.h>
@@ -12,20 +12,7 @@ int sagetexecname (stralloc *sa)
   return sareadlink(sa, SKALIBS_PROCSELFEXE) ;
 }
 
-#elif defined(SKALIBS_HASGETEXECNAME)
-
-#include <skalibs/nonposix.h>
-#include <stdlib.h>
-
-#include <skalibs/stralloc.h>
-#include <skalibs/djbunix.h>
-
-int sagetexecname (stralloc *sa)
-{
-  return sarealpath(sa, getexecname()) ;
-}
-
-#elif defined(SKALIBS_HASKERNPROCPATHNAME)
+#elif defined(SKALIBS_HASKERNPROCPATHNAME)  /* FreeBSD, NetBSD */
 
 #include <skalibs/nonposix.h>
 #ifdef __NetBSD__
@@ -47,7 +34,7 @@ int sagetexecname (stralloc *sa)
   return 0 ;
 }
 
-#elif defined(SKALIBS_HAS_NSGETEXECUTABLEPATH)
+#elif defined(SKALIBS_HAS_NSGETEXECUTABLEPATH)  /* MacOS */
 
 #include <skalibs/nonposix.h>
 #include <sys/types.h>
@@ -65,7 +52,7 @@ int sagetexecname (stralloc *sa)
   return sarealpath(sa, buf) ;
 }
 
-#elif defined(SKALIBS_HASGETAUXVAL)
+#elif defined(SKALIBS_HASGETAUXVAL)  /* Hurd */
 
 #include <skalibs/nonposix.h>
 #include <sys/auxv.h>
@@ -79,7 +66,7 @@ int sagetexecname (stralloc *sa)
   return sarealpath(sa, (char const *)x) ;
 }
 
-#elif defined(SKALIBS_HASDLADDR)
+#elif defined(SKALIBS_HASDLADDR)  /* hack that only works with dynamic binaries */
 
 #include <skalibs/nonposix.h>
 #include <dlfcn.h>
@@ -96,6 +83,19 @@ int sagetexecname (stralloc *sa)
   return 0 ;
 }
 
+#elif defined(SKALIBS_HASGETEXECNAME)  /* bad: it will probably give argv[0] */
+
+#include <skalibs/nonposix.h>
+#include <stdlib.h>
+
+#include <skalibs/stralloc.h>
+#include <skalibs/djbunix.h>
+
+int sagetexecname (stralloc *sa)
+{
+  return sarealpath(sa, getexecname()) ;
+}
+
 #else  /* we tried */
 
 #include <errno.h>
diff --git a/src/sysdeps/trygetexecname.c b/src/sysdeps/trygetexecname.c
index ac65071..909a108 100644
--- a/src/sysdeps/trygetexecname.c
+++ b/src/sysdeps/trygetexecname.c
@@ -3,6 +3,10 @@
 #undef _POSIX_C_SOURCE
 #undef _XOPEN_SOURCE
 
+#ifndef __EXTENSIONS__
+#define __EXTENSIONS__
+#endif
+
 #include <stdlib.h>
 
 int main (void)
-- 
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