From 28e09b5eb76919122f8baf57899154b3dd5fdaa0 Mon Sep 17 00:00:00 2001
From: Laurent Bercot <ska-skaware@skarnet.org>
Date: Wed, 28 Jun 2023 21:27:29 +0000
Subject:  Add workaround for bad QoI posix_spawn()

Signed-off-by: Laurent Bercot <ska@appnovation.com>
---
 src/libstddjb/child_spawn0.c | 56 ++++++++++++++++++++++++++------------------
 1 file changed, 33 insertions(+), 23 deletions(-)

(limited to 'src/libstddjb/child_spawn0.c')

diff --git a/src/libstddjb/child_spawn0.c b/src/libstddjb/child_spawn0.c
index 5b59b20..cfd78f8 100644
--- a/src/libstddjb/child_spawn0.c
+++ b/src/libstddjb/child_spawn0.c
@@ -1,42 +1,59 @@
 /* ISC license. */
 
 #include <skalibs/sysdeps.h>
+
 #include <errno.h>
 
 #ifdef SKALIBS_HASPOSIXSPAWN
 
 #include <signal.h>
-#include <spawn.h>
 #include <stdlib.h>
+#include <spawn.h>
 
 #include <skalibs/config.h>
 
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+# include <skalibs/djbunix.h>
+# include "child_spawn-internal.h"
+#endif
+
 pid_t child_spawn0 (char const *prog, char const *const *argv, char const *const *envp)
 {
   pid_t pid ;
   posix_spawnattr_t attr ;
+  sigset_t set ;
   int e ;
   int nopath = !getenv("PATH") ;
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  int p[2] ;
+  if (pipecoe(p) == -1) return 0 ;
+#endif
   e = posix_spawnattr_init(&attr) ;
   if (e) goto err ;
-  {
-    sigset_t set ;
-    sigemptyset(&set) ;
-    e = posix_spawnattr_setsigmask(&attr, &set) ;
-    if (e) goto errattr ;
-    e = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK) ;
-    if (e) goto errattr ;
-  }
+  sigemptyset(&set) ;
+  e = posix_spawnattr_setsigmask(&attr, &set) ;
+  if (e) goto errattr ;
+  e = posix_spawnattr_setflags(&attr, POSIX_SPAWN_SETSIGMASK) ;
+  if (e) goto errattr ;
   if (nopath && (setenv("PATH", SKALIBS_DEFAULTPATH, 0) < 0)) { e = errno ; goto errattr ; }
   e = posix_spawnp(&pid, prog, 0, &attr, (char *const *)argv, (char *const *)envp) ;
   if (nopath) unsetenv("PATH") ;
+  if (e) goto errattr ;
+
   posix_spawnattr_destroy(&attr) ;
-  if (e) goto err ;
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  return child_spawn_workaround(pid, p) ;
+#else
   return pid ;
+#endif
 
  errattr:
   posix_spawnattr_destroy(&attr) ;
  err:
+#ifdef SKALIBS_HASPOSIXSPAWNEARLYRETURN
+  fd_close(p[1]) ;
+  fd_close(p[0]) ;
+#endif
   errno = e ;
   return 0 ;
 }
@@ -44,10 +61,8 @@ pid_t child_spawn0 (char const *prog, char const *const *argv, char const *const
 #else
 
 #include <unistd.h>
-#include <string.h>
 
 #include <skalibs/allreadwrite.h>
-#include <skalibs/strerr.h>
 #include <skalibs/sig.h>
 #include <skalibs/djbunix.h>
 #include <skalibs/exec.h>
@@ -56,8 +71,9 @@ pid_t child_spawn0 (char const *prog, char const *const *argv, char const *const
 {
   pid_t pid ;
   int p[2] ;
-  unsigned char c ;
-  if (pipecoe(p) < 0) return 0 ;
+  char c ;
+
+  if (pipecoe(p) == -1) return 0 ;
   pid = fork() ;
   if (pid < 0)
   {
@@ -67,20 +83,14 @@ pid_t child_spawn0 (char const *prog, char const *const *argv, char const *const
   }
   if (!pid)
   {
-    size_t len = strlen(PROG) ;
-    char name[len + 9] ;
-    memcpy(name, PROG, len) ;
-    memcpy(name + len, " (child)", 9) ;
-    PROG = name ;
-    fd_close(p[0]) ;
     sig_blocknone() ;
     exec_ae(prog, argv, envp) ;
     c = errno ;
-    fd_write(p[1], (char *)&c, 1) ;
+    fd_write(p[1], &c, 1) ;
     _exit(127) ;
   }
   fd_close(p[1]) ;
-  p[1] = fd_read(p[0], (char *)&c, 1) ;
+  p[1] = fd_read(p[0], &c, 1) ;
   if (p[1] < 0)
   {
     fd_close(p[0]) ;
@@ -90,7 +100,7 @@ pid_t child_spawn0 (char const *prog, char const *const *argv, char const *const
   if (p[1])
   {
     wait_pid(pid, &p[0]) ;
-    errno = c ;
+    errno = (unsigned char)c ;
     return 0 ;
   }
   return pid ;
-- 
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