From f9b855a56b13708e2224efa54060b90539406383 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Tue, 2 Feb 2021 16:59:14 +0000
Subject:  Make if propagate failure code

---
 doc/if.html       | 17 ++++++++++-------
 src/execline/if.c | 13 +++++++------
 2 files changed, 17 insertions(+), 13 deletions(-)

diff --git a/doc/if.html b/doc/if.html
index 700ee59..99be53e 100644
--- a/doc/if.html
+++ b/doc/if.html
@@ -38,19 +38,22 @@
 then waits for it to complete. </li>
  <li> If <em>prog1</em> crashes, <tt>if</tt> prints an error message
 then exits 128 plus the number of the signal that killed <em>prog1</em>. </li>
- <li> If <em>prog1</em> exits a non-zero status,
-<tt>if</tt> exits 1.</li>
+ <li> If <em>prog1</em> exits with a non-zero code, <tt>if</tt> exits with an
+<a href="exitcodes.html">approximation</a> of that code. </li>
  <li> Else <tt>if</tt> execs into <em>prog2</em>. </li>
 </ul>
 
 <h2> Options </h2>
 
 <ul>
- <li> <tt>-X</tt>&nbsp;: treat a crash of <em>prog1</em> as a non-zero ("false") exit.
- <li> <tt>-n</tt>&nbsp;: negate the test (exit on true, exec into <em>prog2</em> on false) </li>
- <li> <tt>-x</tt>&nbsp;<em>exitcode</em>&nbsp;: exit <em>exitcode</em> instead of 1 if the test fails. </li>
- <li> <tt>-t</tt>&nbsp;: exit 0 instead of 1 if the test fails.
-This is equivalent to <tt>-x 0</tt>. </li>
+ <li> <tt>-X</tt>&nbsp;: treat a crash of <em>prog1</em> as a non-zero ("false") exit. This
+is mostly useful in combination with <tt>-n</tt>. </li>
+ <li> <tt>-n</tt>&nbsp;: negate the test. If <em>prog1</em> exits true, then <tt>if</tt> will
+exit 1; else it will exec into <em>prog2</em>. </li>
+ <li> <tt>-x</tt>&nbsp;<em>exitcode</em>&nbsp;: if <tt>if</tt> needs to exit, it will exit <em>exitcode</em>
+instead of whatever else it would have exited. </li>
+ <li> <tt>-t</tt>&nbsp;: if <tt>if</tt> needs to exit, it will exit 0. This is equivalent
+to <tt>-x 0</tt>. </li>
 </ul>
 
 <h2> Notes </h2>
diff --git a/src/execline/if.c b/src/execline/if.c
index a37ecbc..8820dfa 100644
--- a/src/execline/if.c
+++ b/src/execline/if.c
@@ -11,12 +11,13 @@
 #include <execline/execline.h>
 
 #define USAGE "if [ -n ] [ -X ] [ -t | -x exitcode ] { command... }"
+#define dieusage() strerr_dieusage(100, USAGE) ;
 
 int main (int argc, char const **argv, char const *const *envp)
 {
   int argc1, wstat ;
   pid_t pid ;
-  int not = 0, flagnormalcrash = 0 ;
+  int not = 0, fixed = 0, flagnormalcrash = 0 ;
   unsigned short e = 1 ;
   PROG = "if" ;
   {
@@ -27,11 +28,11 @@ int main (int argc, char const **argv, char const *const *envp)
       if (opt == -1) break ;
       switch (opt)
       {
-        case 'n' : not = 1 ; break ;
+        case 'n' : not = 1 ; fixed = 1 ; break ;
         case 'X' : flagnormalcrash = 1 ; break ;
-        case 't' : e = 0 ; break ;
-        case 'x' : if (ushort_scan(l.arg, &e)) break ;
-        default : strerr_dieusage(100, USAGE) ;
+        case 't' : e = 0 ; fixed = 1 ; break ;
+        case 'x' : if (!ushort_scan(l.arg, &e)) dieusage() ; fixed = 1 ; break ;
+        default : dieusage() ;
       }
     }
     argc -= l.ind ; argv += l.ind ;
@@ -49,6 +50,6 @@ int main (int argc, char const **argv, char const *const *envp)
     fmt[uint_fmt(fmt, WTERMSIG(wstat))] = 0 ;
     strerr_dief2x(128 + WTERMSIG(wstat), "child crashed with signal ", fmt) ;
   }
-  if (not == !wait_estatus(wstat)) return e ;
+  if (not == !wait_estatus(wstat)) return fixed ? e : wait_estatus(wstat) ;
   xexec0_e(argv+argc1+1, envp) ;
 }
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