OS-2356 mdb should support embedded dmods in core dumps

Reviewed by: Dave Pacheco <dap@joyent.com>

4 files changed, 234 insertions, 12 deletions

diff --git a/usr/src/cmd/mdb/Makefile.mdb b/usr/src/cmd/mdb/Makefile.mdb
index 9d1d7b4d6c..91c043c29c 100644
--- a/usr/src/cmd/mdb/Makefile.mdb
+++ b/usr/src/cmd/mdb/Makefile.mdb
@@ -67,6 +67,7 @@ SRCS += \
 	mdb_memio.c \
 	mdb_modapi.c \
 	mdb_module.c \
+	mdb_module_dump.c \
 	mdb_module_load.c \
 	mdb_nm.c \
 	mdb_nv.c \
diff --git a/usr/src/cmd/mdb/common/mdb/mdb_module.h b/usr/src/cmd/mdb/common/mdb/mdb_module.h
index 04cb3d1cee..1624d44785 100644
--- a/usr/src/cmd/mdb/common/mdb/mdb_module.h
+++ b/usr/src/cmd/mdb/common/mdb/mdb_module.h
@@ -22,13 +22,11 @@
 /*
  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
  * Use is subject to license terms.
- * Copyright (c) 2012 by Delphix. All rights reserved.
- * Copyright (c) 2012 Joyent, Inc. All rights reserved.
  */
 
 /*
  * Copyright (c) 2012 by Delphix. All rights reserved.
- * Copyright (c) 2012 Joyent, Inc. All rights reserved.
+ * Copyright (c) 2013 Joyent, Inc. All rights reserved.
  */
 
 #ifndef	_MDB_MODULE_H
@@ -112,6 +110,7 @@ extern int mdb_module_remove_walker(mdb_module_t *, const char *);
 extern int mdb_module_create(const char *, const char *, int, mdb_module_t **);
 
 extern int mdb_module_validate_name(const char *, const char **);
+extern int mdb_module_dumpfd(int, uintptr_t, uintptr_t);
 
 #endif	/* _MDB */
 
diff --git a/usr/src/cmd/mdb/common/mdb/mdb_module_dump.c b/usr/src/cmd/mdb/common/mdb/mdb_module_dump.c
new file mode 100644
index 0000000000..6694c94b83
--- /dev/null
+++ b/usr/src/cmd/mdb/common/mdb/mdb_module_dump.c
@@ -0,0 +1,64 @@
+/*
+ * This file and its contents are supplied under the terms of the
+ * Common Development and Distribution License ("CDDL"), version 1.0.
+ * You may only use this file in accordance with the terms of version
+ * 1.0 of the CDDL.
+ *
+ * A full copy of the text of the CDDL should have accompanied this
+ * source.  A copy of the CDDL is also available via the Internet at
+ * http://www.illumos.org/license/CDDL.
+ */
+
+/*
+ * Copyright (c) 2013 Joyent, Inc.  All rights reserved.
+ */
+
+/*
+ * Dump a region of memory from a target and dump it to a temporary file. This
+ * only makes sense for mdb, not for kmdb.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <libproc.h>
+#include <sys/sysmacros.h>
+#include <errno.h>
+#include <strings.h>
+
+#include <mdb/mdb_module.h>
+#include <mdb/mdb.h>
+
+int
+mdb_module_dumpfd(int fd, uintptr_t tgtaddr, size_t tgtsize)
+{
+#ifdef _KMDB
+	return (-1);
+#endif
+	int toread, towrite, ret;
+	char buf[1024];
+
+	while (tgtsize > 0) {
+		toread = MIN(sizeof (buf), tgtsize);
+		towrite = mdb_vread(buf, toread, tgtaddr);
+		if (towrite < 0) {
+			mdb_printf("failed to read dmod from target");
+			return (-1);
+		}
+		tgtsize -= towrite;
+		tgtaddr += towrite;
+		do {
+			ret = write(fd, buf, towrite);
+			if (ret > 0)
+				towrite -= ret;
+		} while (ret < towrite && errno == EINTR);
+
+		if (ret < 0) {
+			mdb_printf("failed to write to temporary dmod "
+			    "file: %s\n", strerror(errno));
+			return (-1);
+		}
+	}
+
+	return (0);
+}
diff --git a/usr/src/cmd/mdb/common/mdb/mdb_module_load.c b/usr/src/cmd/mdb/common/mdb/mdb_module_load.c
index 811af3dd47..5eb4570f00 100644
--- a/usr/src/cmd/mdb/common/mdb/mdb_module_load.c
+++ b/usr/src/cmd/mdb/common/mdb/mdb_module_load.c
@@ -22,11 +22,12 @@
 /*
  * Copyright (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2012 by Delphix. All rights reserved.
- * Copyright (c) 2012 Joyent, Inc. All rights reserved.
+ * Copyright (c) 2013 Joyent, Inc. All rights reserved.
  */
 
 #include <sys/param.h>
 #include <unistd.h>
+#include <stdlib.h>
 #include <strings.h>
 #include <dlfcn.h>
 #include <ctype.h>
@@ -41,6 +42,149 @@
 #include <mdb/mdb_frame.h>
 #include <mdb/mdb.h>
 
+typedef struct mdb_modload_data {
+	int mld_first;
+	int mld_mode;
+} mdb_modload_data_t;
+
+#ifndef _KMDB
+static int
+mdb_module_load_targmod(const char *name, char *buf, size_t buflen,
+    uintptr_t targaddr, uintptr_t targsize)
+{
+	int fd, ret;
+	char *template = "/tmp/.mdb_mod_%s.pid%d.XXXXXX";
+
+	(void) mdb_iob_snprintf(buf, buflen, template, name, getpid());
+	fd = mkstemp(buf);
+	if (fd == -1) {
+		mdb_printf("failed to create temporary file "
+		    "for dmod %s: %s\n", buf,
+		    strerror(errno));
+		return (-1);
+	}
+	ret = mdb_module_dumpfd(fd, targaddr, targsize);
+	(void) close(fd);
+	if (ret != 0)
+		(void) unlink(buf);
+
+	return (ret);
+}
+
+static int
+mdb_module_load_fromtarg(const char *mname, char *pathbuf, size_t buflen)
+{
+	char buf[256], name[256];
+	char *p;
+	GElf_Sym sym;
+
+	if (mdb.m_target == NULL)
+		return (1);
+
+	/*
+	 * See mdb_module_load() for details about the symbol names we test for
+	 * here.
+	 */
+	(void) strlcpy(name, mname, sizeof (name));
+	if ((p = strrchr(name, '.')) != NULL && *++p != '\0') {
+		if (strisnum(p) || strcmp(p, "so") == 0) {
+			(void) mdb_iob_snprintf(buf, sizeof (buf),
+			    "mdb_%s_start", name);
+			if (mdb_lookup_by_name(buf, &sym) == 0)
+				goto found;
+		}
+
+		while (strisnum(p) && (p = strrchr(name, '.')) != NULL) {
+			*p = '\0'; /* strip trailing digits */
+			(void) mdb_iob_snprintf(buf, sizeof (buf),
+			    "mdb_%s_start", name);
+			if (mdb_lookup_by_name(buf, &sym) == 0)
+				goto found;
+		}
+	}
+
+	(void) mdb_iob_snprintf(buf, sizeof (buf), "mdb_%s.so_start",
+	    mname);
+	if (mdb_lookup_by_name(buf, &sym) == 0)
+		goto found;
+
+	return (1);
+
+found:
+	return (mdb_module_load_targmod(mname, pathbuf, buflen,
+	    sym.st_value, sym.st_size));
+}
+
+typedef struct mdb_autoload_arg {
+	int			ma_found;
+	mdb_modload_data_t 	*ma_mld;
+} mdb_autoload_arg_t;
+
+/*
+ * A valid key that we care about will look like: mdb_<module>_start. The module
+ * name will end up being everything inbetween.
+ */
+static int
+mdb_module_autoload_cb(mdb_symbol_t *sym, void *arg)
+{
+	static const char *lead = "mdb_", *end = "_start";
+	static int llen = 4, elen = 6;
+	char *errstr;
+	char buf[256], createbuf[256];
+	int len = strlen(sym->sym_name);
+	mdb_autoload_arg_t *map = arg;
+	int ret;
+
+	if (len < llen + elen + 1)
+		return (0);
+
+	if (strncmp(lead, sym->sym_name, strlen(lead)) != 0)
+		return (0);
+
+	if (strcmp(end, sym->sym_name + len - elen) != 0)
+		return (0);
+
+	(void) strlcpy(buf, sym->sym_name + llen, sizeof (buf));
+	buf[len - llen - elen] = '\0';
+
+	if (!mdb_module_validate_name(buf, (const char **)&errstr))
+		return (0);
+
+	ret = mdb_module_load_targmod(buf, createbuf, sizeof (createbuf),
+	    sym->sym_sym->st_value, sym->sym_sym->st_size);
+	if (ret != 0) {
+		mdb_printf("failed to load module %s from target\n", buf);
+		return (0);
+	}
+	ret = mdb_module_create(buf, createbuf, map->ma_mld->mld_mode, NULL);
+	if (ret == 0) {
+		map->ma_found++;
+		if (mdb.m_term != NULL) {
+			if (map->ma_mld->mld_first == TRUE) {
+				mdb_iob_puts(mdb.m_out, "Loading modules: [");
+				map->ma_mld->mld_first = FALSE;
+			}
+			mdb_iob_printf(mdb.m_out, " %s", buf);
+			mdb_iob_flush(mdb.m_out);
+		}
+	}
+	(void) unlink(createbuf);
+
+	return (0);
+}
+
+static int
+mdb_module_autoload_targ(const char *mname, mdb_modload_data_t *mlp)
+{
+	mdb_autoload_arg_t ma;
+	ma.ma_found = 0;
+	ma.ma_mld = mlp;
+	mdb_symbol_iter(mname, MDB_SYMTAB,
+	    MDB_BIND_ANY | MDB_TYPE_OBJECT, mdb_module_autoload_cb, &ma);
+	return (ma.ma_found);
+}
+#endif /* _KMDB */
+
 int
 mdb_module_load(const char *name, int mode)
 {
@@ -92,9 +236,10 @@ mdb_module_load(const char *name, int mode)
 	}
 
 	/*
-	 * If a simple name is specified, search for it in the module path.
-	 * The module path is searched in order, and for each element we
-	 * look for the following files:
+	 * If a simple name is specified, search of a symbol called
+	 * mdb_<module>_start in the target itself. If that fails, search the
+	 * module apth in order, and for each element look for the following
+	 * files:
 	 *
 	 * 1. If the module name ends in ".so(.[0-9]+)?", search for the literal
 	 *    name and then search for the name without the [0-9]+ suffix.
@@ -104,6 +249,20 @@ mdb_module_load(const char *name, int mode)
 	 * Once a matching file is detected, we attempt to load that module
 	 * and do not resume our search in the case of an error.
 	 */
+
+#ifndef	_KMDB
+	/* Search the target */
+	i = mdb_module_load_fromtarg(name, buf, sizeof (buf));
+	if (i == -1)
+		goto err;
+	if (i == 0) {
+		i = mdb_module_create(name, buf, mode, NULL);
+		(void) unlink(buf);
+		return (i);
+	}
+#endif	/* _KMDB */
+
+	/* Start searching the module path */
 	for (i = 0; mdb.m_lpath[i] != NULL; i++) {
 		if ((p = strrchr(name, '.')) != NULL && *++p != '\0') {
 			if (strisnum(p) || strcmp(p, "so") == 0) {
@@ -143,17 +302,16 @@ err:
 	return (-1);
 }
 
-typedef struct mdb_modload_data {
-	int mld_first;
-	int mld_mode;
-} mdb_modload_data_t;
-
 /*ARGSUSED*/
 static int
 module_load(void *fp, const mdb_map_t *map, const char *fullname)
 {
+	int ret = 0;
 	mdb_modload_data_t *mld = fp;
 	const char *name = strbasename(fullname);
+#ifndef _KMDB
+	(void) mdb_module_autoload_targ(name, mld);
+#endif	/* ! _KMDB */
 
 	if (mdb_module_load(name, mld->mld_mode) == 0 && mdb.m_term != NULL) {
 		if (mld->mld_first == TRUE) {