PSARC/2008/490 pmadvise/pldd unresolved link map flag

6599704 libproc should look inside zones for objects

--HG--
rename : usr/src/lib/libproc/common/Pbrand.c => usr/src/lib/libproc/common/Pzone.c

1 files changed, 748 insertions, 0 deletions

diff --git a/usr/src/lib/libproc/common/Pzone.c b/usr/src/lib/libproc/common/Pzone.c
new file mode 100644
index 0000000000..c4023c2301
--- /dev/null
+++ b/usr/src/lib/libproc/common/Pzone.c
@@ -0,0 +1,748 @@
+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License (the "License").
+ * You may not use this file except in compliance with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+
+/*
+ * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#include <assert.h>
+#include <dlfcn.h>
+#include <errno.h>
+#include <libzonecfg.h>
+#include <link.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/list.h>
+#include <sys/types.h>
+#include <sys/mkdev.h>
+#include <sys/mman.h>
+#include <sys/mnttab.h>
+
+#include "Pcontrol.h"
+
+struct path_node {
+	struct path_node	*pn_next;
+	char			*pn_path;
+};
+typedef struct path_node path_node_t;
+
+static path_node_t *
+pn_push(path_node_t **pnp, char *path)
+{
+	path_node_t *pn;
+
+	if ((pn = calloc(sizeof (path_node_t), 1)) == NULL)
+		return (NULL);
+
+	if ((pn->pn_path = strdup(path)) == NULL) {
+		free(pn);
+		return (NULL);
+	}
+	pn->pn_next = *pnp;
+	return (*pnp = pn);
+}
+
+static void
+pn_free(path_node_t **pnp)
+{
+	path_node_t *pn;
+
+	while (*pnp != NULL) {
+		pn = *pnp;
+		*pnp = pn->pn_next;
+		free(pn->pn_path);
+		free(pn);
+	}
+}
+
+static void
+pn_free2(path_node_t **pn1, path_node_t **pn2)
+{
+	pn_free(pn1);
+	pn_free(pn2);
+}
+
+static char *
+pn_pop(path_node_t **pnp, char *path)
+{
+	path_node_t *pn;
+
+	if (*pnp == NULL)
+		return (NULL);
+
+	pn = *pnp;
+	*pnp = pn->pn_next;
+	pn->pn_next = NULL;
+
+	if (path == NULL) {
+		pn_free(&pn);
+		return (NULL);
+	}
+	(void) strlcpy(path, pn->pn_path, PATH_MAX);
+	pn_free(&pn);
+	return (path);
+}
+
+
+/*
+ * Libzonecfg.so links against libproc, so libproc can't link against
+ * libzonecfg.so.  Also, libzonecfg.so is optional and might not be
+ * installed.  Hence instead of relying on linking to access libzonecfg.so,
+ * we'll try dlopening it here.  This trick is borrowed from
+ * libc`zone_get_id(), see that function for more detailed comments.
+ */
+static int
+i_zone_get_zonepath(char *zone_name, char *zonepath, size_t rp_sz)
+{
+	typedef	int (*zone_get_zonepath_t)(char *, char *, size_t);
+	static zone_get_zonepath_t zone_get_zonepath_fp = NULL;
+
+	if (zone_get_zonepath_fp == NULL) {
+		/* There's no harm in doing this multiple times. */
+		void *dlhandle = dlopen("libzonecfg.so.1", RTLD_LAZY);
+		void *sym = (void *)(-1);
+		if (dlhandle != NULL &&
+		    (sym = dlsym(dlhandle, "zone_get_zonepath")) == NULL) {
+			sym = (void *)(-1);
+			(void) dlclose(dlhandle);
+		}
+		zone_get_zonepath_fp = (zone_get_zonepath_t)sym;
+	}
+
+	/* If we've successfully loaded it, call the real function */
+	if (zone_get_zonepath_fp != (zone_get_zonepath_t)(-1))
+		return (zone_get_zonepath_fp(zone_name, zonepath, rp_sz));
+	return (Z_NO_ZONE);
+}
+
+char *
+Pbrandname(struct ps_prochandle *P, char *buf, size_t buflen)
+{
+	long	addr;
+
+	if ((addr = Pgetauxval(P, AT_SUN_BRANDNAME)) == -1)
+		return (NULL);
+
+	if (Pread_string(P, buf, buflen, addr) == -1)
+		return (NULL);
+
+	return (buf);
+}
+
+/*
+ * Get the zone name from the core file if we have it; look up the
+ * name based on the zone id if this is a live process.
+ */
+char *
+Pzonename(struct ps_prochandle *P, char *s, size_t n)
+{
+	if (P->state == PS_IDLE) {
+		errno = ENODATA;
+		return (NULL);
+	}
+
+	if (P->state == PS_DEAD) {
+		if (P->core->core_zonename == NULL) {
+			errno = ENODATA;
+			return (NULL);
+		}
+		(void) strlcpy(s, P->core->core_zonename, n);
+	} else {
+		if (getzonenamebyid(P->status.pr_zoneid, s, n) < 0)
+			return (NULL);
+		s[n - 1] = '\0';
+	}
+	return (s);
+}
+
+char *
+Pzoneroot(struct ps_prochandle *P, char *s, size_t n)
+{
+	char zname[ZONENAME_MAX], zpath[PATH_MAX], tmp[PATH_MAX];
+	int rv;
+
+	if (P->zoneroot != NULL) {
+		(void) strlcpy(s, P->zoneroot, n);
+		return (s);
+	}
+
+	if ((Pzonename(P, zname, sizeof (zname)) == NULL) ||
+	    (strcmp(zname, GLOBAL_ZONENAME) == 0)) {
+		if ((P->zoneroot = strdup("")) == NULL) {
+			errno = ENOMEM;
+			return (NULL);
+		}
+		dprintf("Pzoneroot defaulting to '%s'\n", GLOBAL_ZONENAME);
+		(void) strlcpy(s, P->zoneroot, n);
+		return (s);
+	}
+
+	if (i_zone_get_zonepath(zname, zpath, sizeof (zpath)) != Z_OK) {
+		if ((P->zoneroot = strdup("")) == NULL) {
+			errno = ENOMEM;
+			return (NULL);
+		}
+		dprintf(
+		    "Pzoneroot zone not found '%s', defaulting to '%s'\n",
+		    zname, GLOBAL_ZONENAME);
+		(void) strlcpy(s, P->zoneroot, n);
+		return (s);
+	}
+	(void) strlcat(zpath, "/root", sizeof (zpath));
+
+	if ((rv = resolvepath(zpath, tmp, sizeof (tmp) - 1)) < 0) {
+		if ((P->zoneroot = strdup("")) == NULL) {
+			errno = ENOMEM;
+			return (NULL);
+		}
+		dprintf(
+		    "Pzoneroot can't access '%s:%s', defaulting to '%s'\n",
+		    zname, zpath, GLOBAL_ZONENAME);
+		(void) strlcpy(s, P->zoneroot, n);
+		return (s);
+	}
+	tmp[rv] = '\0';
+	(void) strlcpy(zpath, tmp, sizeof (zpath));
+
+	if ((P->zoneroot = strdup(zpath)) == NULL) {
+		errno = ENOMEM;
+		return (NULL);
+	}
+	dprintf("Pzoneroot found zone root '%s:%s'\n", zname, zpath);
+	(void) strlcpy(s, P->zoneroot, n);
+	return (s);
+}
+
+/*
+ * Plofspath() takes a path, "path",  and removes any lofs components from
+ * that path.  The resultant path (if different from the starting path)
+ * is placed in "s", which is limited to "n" characters, and the return
+ * value is the pointer s.  If there are no lofs components in the path
+ * the NULL is returned and s is not modified.  It's ok for "path" and
+ * "s" to be the same pointer.  (ie, the results can be stored directly
+ * in the input buffer.)  The path that is passed in must be an absolute
+ * path.
+ *
+ * Example:
+ *	if "path" == "/foo/bar", and "/candy/" is lofs mounted on "/foo/"
+ *	then "/candy/bar/" will be written into "s" and "s" will be returned.
+ */
+char *
+Plofspath(const char *path, char *s, size_t n)
+{
+	char tmp[PATH_MAX + 1];
+	struct mnttab mt, mt_find;
+	FILE *fp;
+	char *p, *p2;
+	int rv;
+
+	dprintf("Plofspath path '%s'\n", path);
+
+	/* We only deal with absolute paths */
+	if (path[0] != '/')
+		return (NULL);
+
+	/* Open /etc/mnttab */
+	if ((fp = fopen(MNTTAB, "r")) == NULL)
+		return (NULL);
+
+	/* Make a copy of the path so that we can muck with it */
+	(void) strlcpy(tmp, path, sizeof (tmp) - 1);
+
+	/*
+	 * Use resolvepath() to make sure there are no consecutive or
+	 * trailing '/'s in the path.
+	 */
+	if ((rv = resolvepath(tmp, tmp, sizeof (tmp) - 1)) >= 0)
+		tmp[rv] = '\0';
+
+	/*
+	 * So now we're going to search the path for any components that
+	 * might be lofs mounts.  We'll start out search from the full
+	 * path and then step back through each parent directly till
+	 * we reach the root.  If we find a lofs mount point in the path
+	 * then we'll replace the initial portion of the path (up
+	 * to that mount point) with the source of that mount point
+	 * and then start our search over again.
+	 *
+	 * Here's some of the variables we're going to use:
+	 *
+	 *	tmp - A pointer to our working copy of the path.  Sometimes
+	 *		this path will be divided into two strings by a
+	 *		'\0' (NUL) character.  The first string is the
+	 *		component we're currently checking and the second
+	 *		string is the path components we've already checked.
+	 *
+	 *	p - A pointer to the last '/' seen in the string.
+	 *
+	 *	p[1] - A pointer to the component of the string we've already
+	 *		checked.
+	 *
+	 * Initially, p will point to the end of our path and p[1] will point
+	 * to an extra '\0' (NUL) that we'll append to the end of the string.
+	 * (This is why we declared tmp with a size of PATH_MAX + 1).
+	 */
+	p = &tmp[strlen(tmp)];
+	p[1] = '\0';
+	for (;;) {
+		/* Check if tmp is a mount point */
+		rewind(fp);
+		bzero(&mt_find, sizeof (mt_find));
+		mt_find.mnt_mountp = tmp;
+		rv = getmntany(fp, &mt, &mt_find);
+
+		/* We only care about lofs mount points */
+		if ((rv == 0) && (strcmp(mt.mnt_fstype, "lofs") == 0)) {
+			char tmp2[PATH_MAX + 1];
+
+			/*
+			 * We found a lofs mount.  Update the path that we're
+			 * checking and start over.  This means append the
+			 * portion of the path we've already checked to the
+			 * source of the lofs mount and re-start this entire
+			 * lofs resolution loop.  Use resolvepath() to make
+			 * sure there are no consecutive or trailing '/'s
+			 * in the path.
+			 */
+			(void) strlcpy(tmp2, mt.mnt_special, sizeof (tmp2) - 1);
+			(void) strlcat(tmp2, "/", sizeof (tmp2) - 1);
+			(void) strlcat(tmp2, &p[1], sizeof (tmp2) - 1);
+			(void) strlcpy(tmp, tmp2, sizeof (tmp) - 1);
+			if ((rv = resolvepath(tmp, tmp, sizeof (tmp) - 1)) >= 0)
+				tmp[rv] = '\0';
+			p = &tmp[strlen(tmp)];
+			p[1] = '\0';
+			continue;
+		}
+
+		/* No lofs mount found */
+		if ((p2 = strrchr(tmp, '/')) == NULL) {
+			char tmp2[PATH_MAX];
+
+			/*
+			 * We know that tmp was an absolute path, so if we
+			 * made it here we know that (p == tmp) and that
+			 * (*p == '\0').  This means that we've managed
+			 * to check the whole path and so we're done.
+			 */
+			assert(p == tmp);
+			assert(p[0] == '\0');
+			(void) fclose(fp);
+
+			/* Restore the leading '/' in the path */
+			p[0] = '/';
+
+			if (strcmp(tmp, path) == 0) {
+				/* The path didn't change */
+				return (NULL);
+			}
+
+			/*
+			 * It's possible that lofs source path we just
+			 * obtained contains a symbolic link.  Use
+			 * resolvepath() to clean it up.
+			 */
+			(void) strlcpy(tmp2, tmp, sizeof (tmp2));
+			if ((rv = resolvepath(tmp, tmp, sizeof (tmp) - 1)) >= 0)
+				tmp[rv] = '\0';
+
+			/*
+			 * It's always possible that our lofs source path is
+			 * actually another lofs mount.  So call ourselves
+			 * recursively to resolve that path.
+			 */
+			(void) Plofspath(tmp, tmp, PATH_MAX);
+
+			/* Copy out our final resolved lofs source path */
+			(void) strlcpy(s, tmp, n);
+			dprintf("Plofspath path result '%s'\n", s);
+			return (s);
+		}
+
+		/*
+		 * So the path we just checked is not a lofs mount.  Next we
+		 * want to check the parent path component for a lofs mount.
+		 *
+		 * First, restore any '/' that we replaced with a '\0' (NUL).
+		 * We can determine if we should do this by looking at p[1].
+		 * If p[1] points to a '\0' (NUL) then we know that p points
+		 * to the end of the string and there is no '/' to restore.
+		 * if p[1] doesn't point to a '\0' (NUL) then it points to
+		 * the part of the path that we've already verified so there
+		 * is a '/' to restore.
+		 */
+		if (p[1] != '\0')
+			p[0] = '/';
+
+		/*
+		 * Second, replace the last '/' in the part of the path
+		 * that we've already checked with a '\0' (NUL) so that
+		 * when we loop around we check the parent component of the
+		 * path.
+		 */
+		p2[0] = '\0';
+		p = p2;
+	}
+	/*NOTREACHED*/
+}
+
+/*
+ * Pzonepath() - Way too much code to attempt to derive the full path of
+ * an object within a zone.
+ *
+ * Pzonepath() takes a path and attempts to resolve it relative to the
+ * root associated with the current process handle.  If it fails it will
+ * not update the results string.  It is safe to specify the same pointer
+ * for the file string and the results string.
+ *
+ * Doing this resolution is more difficult than it initially sounds.
+ * We can't simply append the file path to the zone root, because in
+ * a root directory, '..' is treated the same as '.'.  Also, symbolic
+ * links that specify an absolute path need to be interpreted relative
+ * to the zone root.
+ *
+ * It seems like perhaps we could do a chroot(<zone root>) followed by a
+ * resolvepath().  But we can't do this because chroot requires special
+ * privileges and affects the entire process.  Perhaps if there was a
+ * special version of resolvepath() which took an addition root path
+ * we could use that, but this isn't ideal either.  The reason is
+ * that we want to have special handling for native paths.  (A native path
+ * is a path that begins with "/native/" or "/.SUNWnative/".)  Native
+ * paths could be passed explicity to this function or could be embedded
+ * in a symlink that is part of the path passed into this function.
+ * These paths are always lofs mounts of global zone paths, but lofs
+ * mounts only exist when a zone is booted.  So if we were to try to do
+ * a resolvepath() on a native path when the zone wasn't booted the
+ * resolvepath() would fail even though we know that the components
+ * exists in the global zone.
+ *
+ * Given all these constraints, we just implement a path walking function
+ * that resolves a file path relative to a zone root by manually inspecting
+ * each of the path components and verifying its existence.  This means that
+ * we must have access to the zone and that all the components of the
+ * path must exist for this operation to succeed.
+ */
+char *
+Pzonepath(struct ps_prochandle *P, const char *path, char *s, size_t n)
+{
+	char zroot[PATH_MAX], zpath[PATH_MAX], tmp[PATH_MAX], link[PATH_MAX];
+	path_node_t *pn_stack = NULL, *pn_links = NULL, *pn;
+	struct stat64 sb;
+	char *p;
+	int i, rv;
+
+	dprintf("Pzonepath lookup '%s'\n", path);
+
+	/* First lookup the zone root */
+	if (Pzoneroot(P, zroot, sizeof (zroot)) == NULL)
+		return (NULL);
+
+	/*
+	 * Make a temporary copy of the path specified.
+	 * If it's a relative path then make it into an absolute path.
+	 */
+	tmp[0] = '\0';
+	if (path[0] != '/')
+		(void) strlcat(tmp, "/", sizeof (tmp));
+	(void) strlcat(tmp, path, sizeof (tmp));
+
+	/*
+	 * If the path that was passed in is the zone root, we're done.
+	 * If the path that was passed in already contains the zone root
+	 * then strip the zone root out and verify the rest of the path.
+	 */
+	if (strcmp(tmp, zroot) == 0) {
+		(void) Plofspath(zroot, zroot, sizeof (zroot));
+		dprintf("Pzonepath found zone path (1) '%s'\n", zroot);
+		(void) strlcpy(s, zroot, n);
+		return (s);
+	}
+	i = strlen(zroot);
+	if ((strncmp(tmp, zroot, i) == 0) && (tmp[i] == '/'))
+		(void) memmove(tmp, tmp + i, strlen(tmp + i) + 1);
+
+	/* If no path is passed in, then it maps to the zone root */
+	if (strlen(tmp) == 0) {
+		(void) Plofspath(zroot, zroot, sizeof (zroot));
+		dprintf("Pzonepath found zone path (2) '%s'\n", zroot);
+		(void) strlcpy(s, zroot, n);
+		return (s);
+	}
+
+	/*
+	 * Push each path component that we plan to verify onto a stack of
+	 * path components, with parent components at the top of the stack.
+	 * So for example, if we're going to verify the path /foo/bar/bang
+	 * then our stack will look like:
+	 *	foo	(top)
+	 *	bar
+	 *	bang	(bottom)
+	 */
+	while ((p = strrchr(tmp, '/')) != NULL) {
+		*p = '\0';
+		if (pn_push(&pn_stack, &p[1]) != NULL)
+			continue;
+		pn_free(&pn_stack);
+		return (NULL);
+	}
+
+	/* We're going to store the final zone relative path in zpath */
+	*zpath = '\0';
+
+	while (pn_pop(&pn_stack, tmp) != NULL) {
+		/*
+		 * Drop zero length path components (which come from
+		 * consecutive '/'s) and '.' path components.
+		 */
+		if ((strlen(tmp) == 0) || (strcmp(tmp, ".") == 0))
+			continue;
+
+		/*
+		 * Check the current path component for '..', if found
+		 * drop any previous path component.
+		 */
+		if (strcmp(tmp, "..") == 0) {
+			if ((p = strrchr(zpath, '/')) != NULL)
+				*p = '\0';
+			continue;
+		}
+
+		/* The path we want to verify now is zpath + / + tmp. */
+		(void) strlcat(zpath, "/", sizeof (zpath));
+		(void) strlcat(zpath, tmp, sizeof (zpath));
+
+		/*
+		 * Check if this is a native object.  A native object is an
+		 * object from the global zone that is running in a branded
+		 * zone.  These objects are lofs mounted into a zone.  So if a
+		 * branded zone is not booted then lofs mounts won't be setup
+		 * so we won't be able to find these objects.  Luckily, we know
+		 * that they exist in the global zone with the same path sans
+		 * the initial native component, so we'll just strip out the
+		 * native component here.
+		 */
+		if ((strncmp(zpath, "/native", sizeof ("/native")) == 0) ||
+		    (strncmp(zpath, "/.SUNWnative",
+		    sizeof ("/.SUNWnative")) == 0)) {
+
+			/* Free any cached symlink paths */
+			pn_free(&pn_links);
+
+			/* Reconstruct the path from our path component stack */
+			*zpath = '\0';
+			while (pn_pop(&pn_stack, tmp) != NULL) {
+				(void) strlcat(zpath, "/", sizeof (zpath));
+				(void) strlcat(zpath, tmp, sizeof (zpath));
+			}
+
+			/* Verify that the path actually exists */
+			rv = resolvepath(zpath, tmp, sizeof (tmp) - 1);
+			if (rv < 0) {
+				dprintf("Pzonepath invalid native path '%s'\n",
+				    zpath);
+				return (NULL);
+			}
+			tmp[rv] = '\0';
+
+			/* Return the path */
+			dprintf("Pzonepath found native path '%s'\n", tmp);
+			(void) Plofspath(tmp, tmp, sizeof (tmp));
+			(void) strlcpy(s, tmp, n);
+			return (s);
+		}
+
+		/*
+		 * Check if the path points to a symlink.  We do this
+		 * explicitly since any absolute symlink needs to be
+		 * interpreted relativly to the zone root and not "/".
+		 */
+		(void) strlcpy(tmp, zroot, sizeof (tmp));
+		(void) strlcat(tmp, zpath, sizeof (tmp));
+		if (lstat64(tmp, &sb) != 0) {
+			pn_free2(&pn_stack, &pn_links);
+			return (NULL);
+		}
+		if (!S_ISLNK(sb.st_mode)) {
+			/*
+			 * Since the lstat64() above succeeded we know that
+			 * zpath exists, since this is not a symlink loop
+			 * around and check the next path component.
+			 */
+			continue;
+		}
+
+		/*
+		 * Symlink allow for paths with loops.  Make sure
+		 * we're not stuck in a loop.
+		 */
+		for (pn = pn_links; pn != NULL; pn = pn->pn_next) {
+			if (strcmp(zpath, pn->pn_path) != 0)
+				continue;
+
+			/* We have a loop.  Fail. */
+			dprintf("Pzonepath symlink loop '%s'\n", zpath);
+			pn_free2(&pn_stack, &pn_links);
+			return (NULL);
+		}
+
+		/* Save this symlink path for future loop checks */
+		if (pn_push(&pn_links, zpath) == NULL) {
+			/* Out of memory */
+			pn_free2(&pn_stack, &pn_links);
+			return (NULL);
+		}
+
+		/* Now follow the contents of the symlink */
+		bzero(link, sizeof (link));
+		if (readlink(tmp, link, sizeof (link)) == -1) {
+			pn_free2(&pn_stack, &pn_links);
+			return (NULL);
+		}
+
+		dprintf("Pzonepath following symlink '%s' -> '%s'\n",
+		    zpath, link);
+
+		/*
+		 * Push each path component of the symlink target onto our
+		 * path components stack since we need to verify each one.
+		 */
+		while ((p = strrchr(link, '/')) != NULL) {
+			*p = '\0';
+			if (pn_push(&pn_stack, &p[1]) != NULL)
+				continue;
+			pn_free2(&pn_stack, &pn_links);
+			return (NULL);
+		}
+
+		/* absolute or relative symlink? */
+		if (*link == '\0') {
+			/* Absolute symlink, nuke existing zpath. */
+			*zpath = '\0';
+			continue;
+		}
+
+		/*
+		 * Relative symlink.  Push the first path component of the
+		 * symlink target onto our stack for verification and then
+		 * remove the current path component from zpath.
+		 */
+		if (pn_push(&pn_stack, link) == NULL) {
+			pn_free2(&pn_stack, &pn_links);
+			return (NULL);
+		}
+		p = strrchr(zpath, '/');
+		assert(p != NULL);
+		*p = '\0';
+		continue;
+	}
+	pn_free(&pn_links);
+
+	/* Place the final result in zpath */
+	(void) strlcpy(tmp, zroot, sizeof (tmp));
+	(void) strlcat(tmp, zpath, sizeof (tmp));
+	(void) strlcpy(zpath, tmp, sizeof (zpath));
+
+	(void) Plofspath(zpath, zpath, sizeof (zpath));
+	dprintf("Pzonepath found zone path (3) '%s'\n", zpath);
+
+	(void) strlcpy(s, zpath, n);
+	return (s);
+}
+
+char *
+Pfindobj(struct ps_prochandle *P, const char *path, char *s, size_t n)
+{
+	int len;
+
+	dprintf("Pfindobj '%s'\n", path);
+
+	/* We only deal with absolute paths */
+	if (path[0] != '/')
+		return (NULL);
+
+	/* First try to resolve the path to some zone */
+	if (Pzonepath(P, path, s, n) != NULL)
+		return (s);
+
+	/* If that fails resolve any lofs links in the path */
+	if (Plofspath(path, s, n) != NULL)
+		return (s);
+
+	/* If that fails then just see if the path exists */
+	if ((len = resolvepath(path, s, n)) > 0) {
+		s[len] = '\0';
+		return (s);
+	}
+
+	return (NULL);
+}
+
+char *
+Pfindmap(struct ps_prochandle *P, map_info_t *mptr, char *s, size_t n)
+{
+	file_info_t *fptr = mptr->map_file;
+	char buf[PATH_MAX];
+	int len;
+
+	/* If it's already been explicity set return that */
+	if ((fptr != NULL) && (fptr->file_rname != NULL)) {
+		(void) strlcpy(s, fptr->file_rname, n);
+		return (s);
+	}
+
+	/* If it's the a.out segment, defer to the magical Pexecname() */
+	if ((P->map_exec == mptr) ||
+	    (strcmp(mptr->map_pmap.pr_mapname, "a.out") == 0) ||
+	    ((fptr != NULL) && (fptr->file_lname != NULL) &&
+	    (strcmp(fptr->file_lname, "a.out") == 0))) {
+		(void) Pexecname(P, buf, sizeof (buf));
+		(void) strlcpy(s, buf, n);
+		return (s);
+	}
+
+	/* Try /proc first to get the real object name */
+	if ((Pstate(P) != PS_DEAD) && (mptr->map_pmap.pr_mapname[0] != '\0')) {
+		(void) snprintf(buf, sizeof (buf), "%s/%d/path/%s",
+		    procfs_path, (int)P->pid, mptr->map_pmap.pr_mapname);
+		if ((len = readlink(buf, buf, sizeof (buf))) > 0) {
+			buf[len] = '\0';
+			(void) Plofspath(buf, buf, sizeof (buf));
+			(void) strlcpy(s, buf, n);
+			return (s);
+		}
+	}
+
+	/*
+	 * If we couldn't get the name from /proc, take the lname and
+	 * try to expand it on the current system to a real object path.
+	 */
+	fptr = mptr->map_file;
+	if ((fptr != NULL) && (fptr->file_lname != NULL)) {
+		(void) strlcpy(buf, fptr->file_lname, sizeof (buf));
+		if (Pfindobj(P, buf, buf, sizeof (buf)) == NULL)
+			return (NULL);
+		(void) strlcpy(s, buf, n);
+		return (s);
+	}
+
+	return (NULL);
+}