xref: /illumos-gate/usr/src/cmd/mdb/common/mdb/mdb_module_load.c (revision 50d4d24e)

/*
 * 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 (c) 2004, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2012 by Delphix. All rights reserved.
 * Copyright 2019 Joyent, Inc.
 * Copyright 2021 Oxide Computer Company
 */

#include <sys/param.h>
#include <unistd.h>
#include <strings.h>
#include <dlfcn.h>
#include <ctype.h>
#include <link.h>

#include <mdb/mdb_module.h>
#include <mdb/mdb_modapi.h>
#include <mdb/mdb_debug.h>
#include <mdb/mdb_string.h>
#include <mdb/mdb_err.h>
#include <mdb/mdb_io.h>
#include <mdb/mdb_frame.h>
#include <mdb/mdb.h>

int
mdb_module_load(const char *name, int mode)
{
	const char *wformat = "no module '%s' could be found\n";
	const char *fullname = NULL;
	char buf[MAXPATHLEN], *p, *q;
	int i;

	ASSERT(!(mode & MDB_MOD_DEFER));

	if (strchr(name, '/') != NULL) {
		ASSERT(!(mode & MDB_MOD_BUILTIN));

		(void) mdb_iob_snprintf(buf, sizeof (buf), "%s",
		    strbasename(name));

		/*
		 * Remove any .so(.[0-9]+)? suffix
		 */
		if ((p = strrchr(buf, '.')) != NULL) {
			for (q = p + 1; isdigit(*q); q++)
				;

			if (*q == '\0') {
				if (q > p + 1) {

					/* found digits to remove */
					*p = '\0';
				}
			}
			if ((p = strrchr(buf, '.')) != NULL) {
				if (strcmp(p, ".so") == 0) {
					*p = '\0';
				}
			}
		}
		fullname = name;
		name = buf;
	}

	if (!mdb_module_validate_name(name, &wformat))
		goto err;

	if (fullname != NULL) {
		if (access(fullname, F_OK) != 0) {
			name = fullname; /* for warn() below */
			goto err;
		}
		return (mdb_module_create(name, fullname, mode, NULL));
	}

	/*
	 * 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:
	 *
	 * 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.
	 * 2. If the module name ends in ".so", search for the literal name.
	 * 3. Search for the module name with ".so" appended.
	 *
	 * Once a matching file is detected, we attempt to load that module
	 * and do not resume our search in the case of an error.
	 */
	for (i = 0; mdb.m_lpath[i] != NULL; i++) {
		if ((p = strrchr(name, '.')) != NULL && *++p != '\0') {
			if (strisnum(p) || strcmp(p, "so") == 0) {
				(void) mdb_iob_snprintf(buf, sizeof (buf),
				    "%s/%s", mdb.m_lpath[i], name);
				mdb_dprintf(MDB_DBG_MODULE,
				    "checking for %s\n", buf);
				if (access(buf, F_OK) == 0) {
					return (mdb_module_create(name, buf,
					    mode, NULL));
				}
			}

			while (strisnum(p) && (p = strrchr(buf, '.')) != NULL) {
				*p = '\0'; /* strip trailing digits */
				mdb_dprintf(MDB_DBG_MODULE,
				    "checking for %s\n", buf);
				if (access(buf, F_OK) == 0) {
					return (mdb_module_create(name, buf,
					    mode, NULL));
				}
			}
		}

		(void) mdb_iob_snprintf(buf, sizeof (buf), "%s/%s.so",
		    mdb.m_lpath[i], name);

		mdb_dprintf(MDB_DBG_MODULE, "checking for %s\n", buf);

		if (access(buf, F_OK) == 0)
			return (mdb_module_create(name, buf, mode, NULL));
	}
err:
	if (!(mode & MDB_MOD_SILENT))
		warn(wformat, name);

	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)
{
	mdb_modload_data_t *mld = fp;
	const char *name = strbasename(fullname);

	if (mdb_module_load(name, mld->mld_mode) == 0 && mdb.m_term != NULL) {
		if (mld->mld_first == TRUE) {
			mdb_iob_puts(mdb.m_out, "Loading modules: [");
			mld->mld_first = FALSE;
		}
		mdb_iob_printf(mdb.m_out, " %s", name);
		mdb_iob_flush(mdb.m_out);
	}

	if (strstr(fullname, "/libc/") != NULL) {
		/*
		 * A bit of a kludge:  because we manage alternately capable
		 * libc instances by mounting the appropriately capable
		 * instance over /lib/libc.so.1, we may find that our object
		 * list does not contain libc.so.1, but rather one of its
		 * hwcap variants.  Unfortunately, there is not a way of
		 * getting from this shared object to the object that it is
		 * effectively interposing on -- which means that without
		 * special processing, we will not load any libc.so dmod.  So
		 * if we see that we have a shared object coming out of the
		 * "libc" directory, we assume that we have a "libc-like"
		 * object, and explicitly load the "libc.so" dmod.
		 */
		return (module_load(fp, map, "libc.so.1"));
	}

	if (strstr(fullname, "ld.so") != NULL) {
		/*
		 * This is even more of a kludge. But if we find something has
		 * basically tried to load ld, we will always implicitly load
		 * the list dmod because several binaries and libraries just
		 * build it as a .o and include it in their ELF object.
		 */
		(void) mdb_module_load("list", mld->mld_mode);
	}

	return (0);
}

void
mdb_module_load_all(int mode)
{
	uint_t oflag = mdb_iob_getflags(mdb.m_out) & MDB_IOB_PGENABLE;
	mdb_modload_data_t mld;

	mld.mld_first = TRUE;
	mld.mld_mode = mode | MDB_MOD_LOCAL | MDB_MOD_SILENT;

	mdb_iob_clrflags(mdb.m_out, oflag);

	(void) mdb_tgt_object_iter(mdb.m_target, module_load, &mld);

	if (mdb.m_term != NULL && mld.mld_first == FALSE)
		mdb_iob_puts(mdb.m_out, " ]\n");

	mdb_iob_setflags(mdb.m_out, oflag);
}

/*ARGSUSED*/
int
mdb_module_unload(const char *name, int mode)
{
	ASSERT((mode & ~MDB_MOD_SILENT) == 0);

	return (mdb_module_unload_common(name));
}