make-3.79 on solaris8 broken

[Kevin Nomura]

Using make-3.79 under solaris 6 and solaris 8, I have been seeing
two intermittent problems.  It seems to get worse with higher values
of -j.   One is "No rule to make target xxx" when there is, in fact, 
a rule to make target xxx.  As befits an intermittent problem, the 
make succeeds if rerun with no changes.

The second problem is more insidious: make *quietly* fails to rebuild
some of its targets that are out of date.  The symptom is link errors
with unsat symbols owing to the incomplete build.  Again, rerunning 
make picks these up and succeeds.  Since this is a chronic problem for 
us I spent this past weekend debugging it with make -d and have some 
theories to offer.

The first problem seems due to the stat() in remake.c not being protected
by a retry loop for EINTR.  stat() on solaris is documented as failing
with EINTR.  So, I fixed this, actually implementing the "safe_stat()"
function that has a prototype in make.h but no definition (!?).  This
cleared up the "No rule" errors but not the unsat link problems.

For the second problem with failed links, the -d trace surrounding one of 
the files that should have been remade (but was not) looked like:

        Considering target file `../netcache/server/obj/td/wccp2.o'.
         Looking for an implicit rule for `../netcache/server/obj/td/wccp2.o'.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/obj/td/wccp2.r'.
Got a SIGCHLD; 1 unreaped children.
Got a SIGCHLD; 2 unreaped children.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/obj/td/wccp2.f'.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/wccp2.c'.
Got a SIGCHLD; 3 unreaped children.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/wccp2.cpp'.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/wccp2.c'.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/wccp2.c'.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/obj/td/wccp2.c'.
         Trying pattern rule with stem `wccp2'.
         Trying implicit prerequisite `../netcache/server/obj/td/wccp2.cc'.
         Trying pattern rule with stem `wccp2'.
...
         No implicit rule found for `../netcache/server/obj/td/wccp2.o'.
...
        No commands for `../netcache/server/obj/td/wccp2.o' and no prerequisites
 actually changed.
        No need to remake target `../netcache/server/obj/td/wccp2.o'.

Seeing that a signal happened right about the time it was checking
the prerequisite `../netcache/server/wccp2.c' (the source file, which 
does exist), I zeroed in on the readdir() in dir.c:dir_contents_file_exists_p().
Now, readdir() is not documented in solaris 6 or solaris 8 to fail on EINTR.
But I put in a retry loop anyway and CAUGHT readdir failing on EINTR, dozens
of times in the build in fact.  So with stat() and readdir() (and opendir()
and some others for good measure) guarded by retry loops, the problems have
now subsided.

So assuming these are in fact the causes of the problems I saw, I am
wondering whether solaris is in error for returning EINTR (e.g. is this
broken with respect to POSIX or some standard that Solaris claims
adherence to)?  Should either or both of these be solved within make,
at least as a practical issue?

Kevin Nomura
Network Appliance