Hi,
maybe someone can help me with this fundamental question: I noticed that I
can't
run gcore on apache children when running gcore with the same UID as apache:
h:w$ id
uid=80(webservd) gid=80(webservd)
h:w$ gcore 21731
gcore: cannot grab 21731: permission denied
I've followed some of the gcore/procfs code and finally narrowed down the issue
to the fact that Apache children have got SNOCD set in (proc_t)->p_flag:
~# ps -ef | grep httpd| head -2
root 21731 3056 0 21:00:10 ? 0:00 /usr/apache2/2.2/bin/httpd
webservd 21739 21731 0 21:00:11 ? 0:00 /usr/apache2/2.2/bin/httpd
> 0t21731::pid2proc | ::print proc_t p_flag
p_flag = 0x42000400
> 0t21739::pid2proc | ::print proc_t p_flag
p_flag = 0x52000000
http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/sys/proc.h#SNOCD
500 #define SNOCD 0x10000000 /* new creds from VSxID, do not
coredump */
This is on a plain vanilla snv_111b apache2.2
Now I wonder: Why is this the case? I haven't found anything special in apache,
except for the forkx(), setgid(80), initgroups(), setiud(80) sequence.
Would anyone help me understand this?
P.S.: Passing by gcore, I noticed that it probably doesn't need to open
/proc/<pid>/as with O_RDWR, does it?
diff -r c13e2db06244 usr/src/cmd/gcore/gcore.c
--- a/usr/src/cmd/gcore/gcore.c Sun Jan 03 12:47:17 2010 -0800
+++ b/usr/src/cmd/gcore/gcore.c Fri Jan 15 21:28:17 2010 +0100
@@ -152,7 +152,7 @@
char *prefix = NULL;
int opt;
int opt_p = 0, opt_g = 0, opt_c = 0;
- int oflags = 0;
+ int oflags = PGRAB_RDONLY;
int i;
char fname[MAXPATHLEN];
char path[MAXPATHLEN];
