OS-3280 need a way to specify the root of a native system in the lx brand

OS-3279 lx brand should allow delegated datasets
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>

5 files changed, 48 insertions, 3 deletions

diff --git a/usr/src/lib/libc/inc/thr_uberdata.h b/usr/src/lib/libc/inc/thr_uberdata.h
index de0d4a6b05..1bb08d69b2 100644
--- a/usr/src/lib/libc/inc/thr_uberdata.h
+++ b/usr/src/lib/libc/inc/thr_uberdata.h
@@ -944,6 +944,7 @@ typedef struct uberdata {
 	robust_t	**robustlocks;	/* table of registered robust locks */
 	robust_t	*robustlist;	/* list of registered robust locks */
 	char	*progname;	/* the basename of the program, from argv[0] */
+	char	*ub_broot;	/* the root of the native code in the brand */
 	struct uberdata **tdb_bootstrap;
 	tdb_t	tdb;		/* thread debug interfaces (for libc_db) */
 } uberdata_t;
diff --git a/usr/src/lib/libc/port/gen/getauxv.c b/usr/src/lib/libc/port/gen/getauxv.c
index 500675719c..4356a01392 100644
--- a/usr/src/lib/libc/port/gen/getauxv.c
+++ b/usr/src/lib/libc/port/gen/getauxv.c
@@ -24,9 +24,8 @@
  * Use is subject to license terms.
  */
 
-#pragma ident	"%Z%%M%	%I%	%E% SMI"
-
 #include "lint.h"
+#include "thr_uberdata.h"
 #include <libc.h>
 #include <fcntl.h>
 #include <stdlib.h>
@@ -38,6 +37,7 @@
 #include <thread.h>
 #include <synch.h>
 #include <atomic.h>
+#include <limits.h>
 
 static mutex_t auxlock = DEFAULTMUTEX;
 
@@ -59,11 +59,20 @@ _getaux(int type)
 	if (auxb == NULL) {
 		lmutex_lock(&auxlock);
 		if (auxb == NULL) {
+			uberdata_t *udp = curthread->ul_uberdata;
 			struct stat statb;
 			auxv_t *buf = NULL;
+			char *path = "/proc/self/auxv";
+			char pbuf[PATH_MAX];
 			int fd;
 
-			if ((fd = open("/proc/self/auxv", O_RDONLY)) != -1 &&
+			if (udp->ub_broot != NULL) {
+				(void) snprintf(pbuf, sizeof (pbuf),
+				    "%s/proc/self/auxv", udp->ub_broot);
+				path = pbuf;
+			}
+
+			if ((fd = open(path, O_RDONLY)) != -1 &&
 			    fstat(fd, &statb) != -1)
 				buf = libc_malloc(
 				    statb.st_size + sizeof (auxv_t));
diff --git a/usr/src/lib/libc/port/mapfile-vers b/usr/src/lib/libc/port/mapfile-vers
index d17f543041..ecbb16fe85 100644
--- a/usr/src/lib/libc/port/mapfile-vers
+++ b/usr/src/lib/libc/port/mapfile-vers
@@ -3051,6 +3051,7 @@ $endif
 	zone_list;
 	zone_list_datalink;
 	zonept;
+	zone_get_nroot;
 	zone_remove_datalink;
 	zone_setattr;
 	zone_shutdown;
diff --git a/usr/src/lib/libc/port/sys/zone.c b/usr/src/lib/libc/port/sys/zone.c
index 182a7f22f7..8cf28c3ccf 100644
--- a/usr/src/lib/libc/port/sys/zone.c
+++ b/usr/src/lib/libc/port/sys/zone.c
@@ -26,6 +26,7 @@
  */
 
 #include "lint.h"
+#include "thr_uberdata.h"
 #include <sys/types.h>
 #include <sys/syscall.h>
 #include <sys/zone.h>
@@ -244,3 +245,10 @@ zone_list_datalink(zoneid_t zoneid, int *dlnump, datalink_id_t *linkids)
 {
 	return (syscall(SYS_zone, ZONE_LIST_DATALINK, zoneid, dlnump, linkids));
 }
+
+const char *
+zone_get_nroot()
+{
+	uberdata_t *udp = curthread->ul_uberdata;
+	return (udp->ub_broot);
+}
diff --git a/usr/src/lib/libc/port/threads/thr.c b/usr/src/lib/libc/port/threads/thr.c
index b5d848449d..6050b03fbd 100644
--- a/usr/src/lib/libc/port/threads/thr.c
+++ b/usr/src/lib/libc/port/threads/thr.c
@@ -136,6 +136,7 @@ uberdata_t __uberdata = {
 	NULL,			/* robustlocks */
 	NULL,			/* robustlist */
 	NULL,			/* progname */
+	NULL,			/* ub_broot */
 	NULL,			/* __tdb_bootstrap */
 	{			/* tdb */
 		NULL,		/* tdb_sync_addr_hash */
@@ -1219,6 +1220,24 @@ extern void atfork_init(void);
 extern void __proc64id(void);
 #endif
 
+static void
+init_brandroot(uberdata_t *udp)
+{
+	Dl_argsinfo_t args;
+
+	udp->ub_broot = NULL;
+	if (dlinfo(RTLD_SELF, RTLD_DI_ARGSINFO, &args) < 0)
+		return;
+
+	while (args.dla_auxv->a_type != AT_NULL) {
+		if (args.dla_auxv->a_type == AT_SUN_BRAND_NROOT) {
+			udp->ub_broot = args.dla_auxv->a_un.a_ptr;
+			return;
+		}
+		args.dla_auxv++;
+	}
+}
+
 /*
  * libc_init() is called by ld.so.1 for library initialization.
  * We perform minimal initialization; enough to work with the main thread.
@@ -1255,6 +1274,13 @@ libc_init(void)
 	(void) _atexit(__cleanup);
 
 	/*
+	 * Every libc, regardless of link map, needs to go through and check its
+	 * aux vectors so as to indicate whether or not this has been given a
+	 * brand root with which we use to qualify various other data.
+	 */
+	init_brandroot(udp);
+
+	/*
 	 * We keep our uberdata on one of (a) the first alternate link map
 	 * or (b) the primary link map.  We switch to the primary link map
 	 * and stay there once we see it.  All intermediate link maps are