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[pf3gnuchains/gcc-fork.git] / libiberty / pex-unix.c

diff --git a/libiberty/pex-unix.c b/libiberty/pex-unix.c
index 4428f60..85733a6 100644 (file)
--- a/libiberty/pex-unix.c
+++ b/libiberty/pex-unix.c
@@ -400,6 +400,12 @@ pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
   volatile int sleep_interval;
   volatile int retries;
 
+  /* We vfork and then set environ in the child before calling execvp.
+     This clobbers the parent's environ so we need to restore it.
+     It would be nice to use one of the exec* functions that takes an
+     environment as a parameter, but that may have portability issues.  */
+  char **save_environ = environ;
+
   sleep_interval = 1;
   pid = -1;
   for (retries = 0; retries < 4; ++retries)
@@ -453,7 +459,12 @@ pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
        }
 
       if (env)
-        environ = (char**) env;
+       {
+         /* NOTE: In a standard vfork implementation this clobbers the
+            parent's copy of environ "too" (in reality there's only one copy).
+            This is ok as we restore it below.  */
+         environ = (char**) env;
+       }
 
       if ((flags & PEX_SEARCH) != 0)
        {
@@ -471,6 +482,14 @@ pex_unix_exec_child (struct pex_obj *obj, int flags, const char *executable,
 
     default:
       /* Parent process.  */
+
+      /* Restore environ.
+        Note that the parent either doesn't run until the child execs/exits
+        (standard vfork behaviour), or if it does run then vfork is behaving
+        more like fork.  In either case we needn't worry about clobbering
+        the child's copy of environ.  */
+      environ = save_environ;
+
       if (in != STDIN_FILE_NO)
        {
          if (close (in) < 0)