[PATCH 09/18] libxl: fork: Rename sigchld handler functions

[Ian Jackson <ian.jackson@eu.citrix.com>]

We are going to change these functions so that different libxl ctx's
can share a single SIGCHLD handler.  Rename them now to a new name
which doesn't imply unconditional handler installation or removal.

Also note in the comments that they are idempotent.

No functional change.

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Jim Fehlig <jfehlig@suse.com>
Cc: Ian Campbell <Ian.Campbell@citrix.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
---
 tools/libxl/libxl.c          |    2 +-
 tools/libxl/libxl_fork.c     |   22 +++++++++++-----------
 tools/libxl/libxl_internal.h |    4 ++--
 3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
index 2845ca4..4679b51 100644
--- a/tools/libxl/libxl.c
+++ b/tools/libxl/libxl.c
@@ -170,7 +170,7 @@ int libxl_ctx_free(libxl_ctx *ctx)
     /* If we have outstanding children, then the application inherits
      * them; we wish the application good luck with understanding
      * this if and when it reaps them. */
-    libxl__sigchld_removehandler(gc);
+    libxl__sigchld_notneeded(gc);
 
     if (ctx->sigchld_selfpipe[0] >= 0) {
         close(ctx->sigchld_selfpipe[0]);
diff --git a/tools/libxl/libxl_fork.c b/tools/libxl/libxl_fork.c
index 16e17f6..a15af8e 100644
--- a/tools/libxl/libxl_fork.c
+++ b/tools/libxl/libxl_fork.c
@@ -194,7 +194,7 @@ static void sigchld_removehandler_core(void)
     sigchld_owner = 0;
 }
 
-void libxl__sigchld_removehandler(libxl__gc *gc) /* non-reentrant */
+void libxl__sigchld_notneeded(libxl__gc *gc) /* non-reentrant, idempotent */
 {
     int rc;
 
@@ -210,7 +210,7 @@ void libxl__sigchld_removehandler(libxl__gc *gc) /* non-reentrant */
     }
 }
 
-int libxl__sigchld_installhandler(libxl__gc *gc) /* non-reentrant */
+int libxl__sigchld_needed(libxl__gc *gc) /* non-reentrant, idempotent */
 {
     int r, rc;
 
@@ -274,18 +274,18 @@ static bool chldmode_ours(libxl_ctx *ctx, bool creating)
     abort();
 }
 
-static void perhaps_removehandler(libxl__gc *gc)
+static void perhaps_sigchld_notneeded(libxl__gc *gc)
 {
     if (!chldmode_ours(CTX, 0))
-        libxl__sigchld_removehandler(gc);
+        libxl__sigchld_notneeded(gc);
 }
 
-static int perhaps_installhandler(libxl__gc *gc, bool creating)
+static int perhaps_sigchld_needed(libxl__gc *gc, bool creating)
 {
     int rc;
 
     if (chldmode_ours(CTX, creating)) {
-        rc = libxl__sigchld_installhandler(gc);
+        rc = libxl__sigchld_needed(gc);
         if (rc) return rc;
     }
     return 0;
@@ -314,7 +314,7 @@ static int childproc_reaped(libxl__egc *egc, pid_t pid, int status)
  found:
     childproc_reaped_ours(egc, ch, status);
 
-    perhaps_removehandler(gc);
+    perhaps_sigchld_notneeded(gc);
 
     return 0;
 }
@@ -445,7 +445,7 @@ pid_t libxl__ev_child_fork(libxl__gc *gc, libxl__ev_child *ch,
     CTX_LOCK;
     int rc;
 
-    perhaps_installhandler(gc, 1);
+    perhaps_sigchld_needed(gc, 1);
 
     pid_t pid =
         CTX->childproc_hooks->fork_replacement
@@ -473,7 +473,7 @@ pid_t libxl__ev_child_fork(libxl__gc *gc, libxl__ev_child *ch,
     rc = pid;
 
  out:
-    perhaps_removehandler(gc);
+    perhaps_sigchld_notneeded(gc);
     CTX_UNLOCK;
     return rc;
 }
@@ -492,8 +492,8 @@ void libxl_childproc_setmode(libxl_ctx *ctx, const libxl_childproc_hooks *hooks,
     ctx->childproc_hooks = hooks;
     ctx->childproc_user = user;
 
-    perhaps_removehandler(gc);
-    perhaps_installhandler(gc, 0); /* idempotent, ok to ignore errors for now */
+    perhaps_sigchld_notneeded(gc);
+    perhaps_sigchld_needed(gc, 0); /* idempotent, ok to ignore errors for now */
 
     CTX_UNLOCK;
     GC_FREE;
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index 1bd23ff..fba681d 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -838,8 +838,8 @@ _hidden void libxl__poller_wakeup(libxl__egc *egc, libxl__poller *p);
 
 /* Internal to fork and child reaping machinery */
 extern const libxl_childproc_hooks libxl__childproc_default_hooks;
-int libxl__sigchld_installhandler(libxl__gc*); /* non-reentrant; logs errs */
-void libxl__sigchld_removehandler(libxl__gc*); /* non-reentrant */
+int libxl__sigchld_needed(libxl__gc*); /* non-reentrant idempotent, logs errs */
+void libxl__sigchld_notneeded(libxl__gc*); /* non-reentrant idempotent */
 int libxl__self_pipe_wakeup(int fd); /* returns 0 or -1 setting errno */
 int libxl__self_pipe_eatall(int fd); /* returns 0 or -1 setting errno */
 
-- 
1.7.10.4