Nagios Support Forum

I was having a hard time making ndomod.o load on HP-UX (I know, I know). =
Here is a patch for ndomod.c.

It turns out that a library must be execuable to be dlopen'ed, or else =
mmap fails with an EACCES. ndomod.o is executable, but not the temporary =
file it's copied to. There's no option to mkstemp to make an executable, =
temporary file. So I chmod it to make it executable before running =
dlopen.

Furthermore, on HP-UX, it seems that you can't unlink() a library which =
is in use, you get ETXTBSY. So the clever unlink trick, which works on =
Linux, fails. The best thing I found was to chmod 000 the file to =
prevent anyone from accidentally writing to it, and cleaning up the =
temporary directory from the nagios startup script. It could probably be =
cleaned up when unloading the module but I didn't bother. If anybody has =
a better idea or implementation of this, I'll be glad to compile it and =
try it out.

Note: I'm a sysadmin, not a developper. So that basically makes me a =
stupid developper. These workarounds worked for me but don't bash me if =
they're not done right. Do whatever you want with it.=20

Thanks


*** nebmods.c Sat Feb 23 16:12:11 2008
--- nebmods.c.hpux Fri Jun 13 15:00:05 2008
***************
*** 204,209 ****
--- 204,218 ----
logit(NSLOG_RUNTIME_ERROR,FALSE,"Error: Could not safely =
copy module '%s'. The module will not be loaded: =
%s\n",mod->filename,strerror(errno));
return ERROR;
}
+ #ifdef _HPUX_SOURCE
+ /* HP-UX's mmap(), called from dlopen, requires the shared =
library to be executable, else if fails with EACCESS */
+ /* A workaround is making it executable first hand. */
+ if (chmod(output_file,S_IRUSR|S_IWUSR|S_IXUSR) =3D=3D -1)
+ {
+ logit(NSLOG_RUNTIME_ERROR,FALSE,"Error: Could not safely =
make copy of module '%s' executable: =
%s\n",mod->filename,strerror(errno));
+ return ERROR;
+ }
+ #endif
/* open module file for reading and copy it */
if((source_fd=3Dopen(mod->filename,O_RDONLY,0644))>0){
=
while((bytes_read=3Dread(source_fd,buffer,sizeof(buffer)))>0)
***************
*** 240,245 ****
--- 249,263 ----
/* this will prevent other processes from overwriting the file =
(using the same inode), which would cause Nagios to crash */
/* the kernel will keep the deleted file in memory until we =
unload it */
/* NOTE: This *should* be portable to most Unices, but I've only =
tested it on Linux */
+ #ifdef _HPUX_SOURCE
+ /* On HP-UX, we can't unlink a shared library which is in use. =
The best we can do is chmod 000 it, */
+ /* hoping that no bonehead will ever try overwriting the =
contents. The temporary directory must be */
+ /* purged from the nagios startup script, which is a major =
drawback */
+ if (chmod(output_file,0) =3D=3D -1) {
+ logit(NSLOG_RUNTIME_ERROR,FALSE,"Error: Could not safely =
make copy of module '%s' unmodifiable: =
%s\n",mod->filename,strerror(errno));
+ return ERROR;
+ }
+ #else
if(unlink(output_file)=3D=3D-1){
logit(NSLOG_RUNTIME_ERROR,FALSE,"Error: Could not delete =
temporary file '%s' used for module '%s'. The module will be unloaded: =
%s\n",output_file,mod->filename,strerror(errno));
=
neb_unload_module(mod,NEBMODULE_FORCE_UNLOAD,NEBMODULE_ERROR_API_VERSION)=
;
***************
*** 246,251 ****
--- 264,270 ----

return ERROR;
}
+ #endif

/* find module API version */
#ifdef USE_LTDL

=20
--
Olivier Mass=E9
Concepteur exploitation et support
Projets d'automatisation et informatique, Hydro-Qu=E9bec Distribution
(450)441-7200 ext. 7053 [email protected]





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