libxl: child processes cleanups

Abolish libxl_fork.  Its only callers were in xl.  Its functionality
is now moved elsewhere, as follows:

* The "logging version of fork", which is what it was billed as, is now
  xl_fork, which also dies on failure.

* Closing the xenstore handle in the child is now done in
  libxl__ev_child_fork, which is the only remaining place where fork
  is called in libxl.

* We provide a new function libxl__ev_child_xenstore_reopen for
  in-libxl children to make the ctx useable for xenstore again.

* Consequently libxl__spawn_record_pid now no longer needs to mess
  about with its own xenstore handle.  As a bonus it can now just use
  libxl__xs_write.

Also, since we have now converted all the forkers in libxl, we can
always honour the fork_replacement childproc hook - so do so.

Signed-off-by: Ian Jackson <ian.jackson@eu.citrix.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Committed-by: Ian Jackson <Ian.Jackson@eu.citrix.com>

1 files changed, 0 insertions, 21 deletions

diff --git a/tools/libxl/libxl_utils.c b/tools/libxl/libxl_utils.c
index f0d94c6828..858410e7bc 100644
--- a/tools/libxl/libxl_utils.c
+++ b/tools/libxl/libxl_utils.c
@@ -444,27 +444,6 @@ int libxl__remove_directory(libxl__gc *gc, const char *dirpath)
     return rc;
 }
 
-pid_t libxl_fork(libxl_ctx *ctx)
-{
-    pid_t pid;
-
-    pid = fork();
-    if (pid == -1) {
-        LIBXL__LOG_ERRNO(ctx, LIBXL__LOG_ERROR, "fork failed");
-        return -1;
-    }
-
-    if (!pid) {
-        if (ctx->xsh) xs_daemon_destroy_postfork(ctx->xsh);
-        ctx->xsh = 0;
-        /* This ensures that anyone who forks but doesn't exec,
-         * and doesn't reinitialise the libxl_ctx, is OK.
-         * It also means they can safely call libxl_ctx_free. */
-    }
-
-    return pid;
-}
-
 int libxl_pipe(libxl_ctx *ctx, int pipes[2])
 {
     if (pipe(pipes) < 0) {