win32: handle -1 return status from execve(2)

The implementations of execve(2) and execvp(3) were unable to
distinguish between failure and a program returning a status of -1.
Check the error return code to discriminate between these cases.

See GitHub issue #218.

1 files changed, 3 insertions, 2 deletions

diff --git a/win32/process.c b/win32/process.c
index 9e0740d6d..1b344f747 100644
--- a/win32/process.c
+++ b/win32/process.c
@@ -268,6 +268,7 @@ spawnveq(int mode, const char *path, char *const *argv, char *const *env)
                 new_path = xasprintf("%s.", path);
         }
 
+        errno = 0;
         ret = spawnve(mode, new_path ? new_path : path, new_argv, env);
 
  done:
@@ -404,7 +405,7 @@ int
 mingw_execvp(const char *cmd, char *const *argv)
 {
         int ret = (int)mingw_spawn_1(P_WAIT, cmd, argv, environ);
-        if (ret != -1)
+        if (ret != -1 || errno == 0)
                 exit(ret);
         return ret;
 }
@@ -413,7 +414,7 @@ int
 mingw_execve(const char *cmd, char *const *argv, char *const *envp)
 {
         int ret = (int)mingw_spawn_interpreter(P_WAIT, cmd, argv, envp, 0);
-        if (ret != -1)
+        if (ret != -1 || errno == 0)
                 exit(ret);
         return ret;
 }