Shortly, libxl will be juggling multiple parallel operations, and will
possibly have to take error decisions before some tasks have been set up.
No child process of libxl will ever have a pid of 0, so gate
libxl__ev_child_inuse() on a pid strictly greater than 0.
This makes it safe to use on a zeroed structure of a task which has not yet
been set up.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
CC: Ian Campbell <ian.campb...@citrix.com>
CC: Ian Jackson <ian.jack...@eu.citrix.com>
CC: Wei Liu <wei.l...@citrix.com>
---
This change does make libxl__ev_child_init() functionally useless. I am
undecided between leaving it in place in case it is useful in the future, or to
remove it completely.
---
tools/libxl/libxl_internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index e96d6b5..6226c18 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -880,7 +880,7 @@ _hidden pid_t libxl__ev_child_fork(libxl__gc *gc,
libxl__ev_child *childw_out,
static inline void libxl__ev_child_init(libxl__ev_child *childw_out)
{ childw_out->pid = -1; }
static inline int libxl__ev_child_inuse(const libxl__ev_child *childw_out)
- { return childw_out->pid >= 0; }
+ { return childw_out->pid > 0; }
/* Useable (only) in the child to once more make the ctx useable for
* xenstore operations. logs failure in the form "what: <error
--
1.7.10.4
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