On Tue, 19 May 2015, Nach wrote:
> posix_spawn is supposed to return a value indicating an error when it fails.
> The specification for it is here:
> http://pubs.opengroup.org/onlinepubs/9699919799/functions/posix_spawn.html
...
> From the spec: Otherwise, no child process shall be created, the value
> stored into the variable pointed to by a non-NULL pid is unspecified,
> and *an error number shall be returned as the function return value*
> to indicate the error.
The standard also later says:
----
These functions may fail if:
[EINVAL] The value specified by file_actions or attrp is invalid.
If this error occurs after the calling process successfully returns from
the posix_spawn() or posix_spawnp() function, the child process may exit
with exit status 127.
If posix_spawn() or posix_spawnp() fail for any of the reasons that
would cause fork() or one of the exec family of functions to fail, an
error value shall be returned as described by fork() and exec,
respectively (or, if the error occurs after the calling process
successfully returns, the child process shall exit with exit status 127).
----
The permission there to have the child process exit with exit status 127
without successful execution of the target executable directly contradicts
the apparent requirement of the RETURN VALUES section.
The rationale for the posix_spawn interface explicitly calls out that it
was intended and desired for the interface to be implementable without
kernel changes, so we believe this is an error in the RETURN VALUES
section of the standard and do not feel this is a bug in our
implementation.
Philip Guenther
