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/*
* libpulp - User-space Livepatching Library
*
* Copyright (C) 2024 SUSE Software Solutions GmbH
*
* This file is part of libpulp.
*
* libpulp is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* libpulp is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with libpulp. If not, see <http://www.gnu.org/licenses/>.
*/
/* Small interface that allows livepatches to be applied or reverted
* within gdb. There is no need to compile this file if
* ENABLE_GDB_INTERFACE is not defined.
*/
#include "config.h"
#ifdef ENABLE_GDB_INTERFACE
#ifndef _GNU_SOURCE
#define _GNU_SOURCE
#endif
#include <string.h>
#include <sys/types.h>
#include <link.h>
#include "ulp_common.h"
#include "ulp.h"
#include "minielf.h"
#include "error_common.h"
#include "insn_queue_lib.h"
extern char __ulp_metadata_buffer[ULP_METADATA_BUF_LEN];
int
inject_lp_path(const char *path, long metadata_size)
{
/* FIXME: This is absurdly awkward. */
/* Copy the final metadata into final_meta buffer. Things works here as
* follows:
*
* 1. Copy the first 1 + 32 bytes containing the patch type and patch id.
* 2. Copy the size of the path to the livepatch container file.
* 3. Copy the path to the livepatch container file.
* 4. Copy the remaining metadata stuff.
*
* We do it in this way so we don't have to carry the path to the patch
* container with the patch. This info can be retrieved from the path to
* patch and avoid problems regarding the application running in another path
* than the ulp tool.
*
* See introspection.c: 1868.
* */
long metadata_left = 1 + 32;
long metadata_right = metadata_size - metadata_left;
char *head = &__ulp_metadata_buffer[metadata_left];
uint32_t path_size = strlen(path) + 1;
uint32_t path_object_size = sizeof(uint32_t) + path_size;
/* Check if it will still fit the metadata buffer. */
if (metadata_size + path_object_size > ULP_METADATA_BUF_LEN) {
/* Won't fit. */
return ENOMEM;
}
/* Shift right so it fits. */
memmove(head + path_object_size, head, metadata_right);
/* Inject the path. */
memcpy(head, &path_size, sizeof(uint32_t));
head += sizeof(uint32_t);
memcpy(head, path, path_size);
head += path_object_size;
return 0;
}
int
gdb_ulp_apply(const char *path)
{
int ret;
/* Prepare the ULP metadata buffer. */
memset(__ulp_metadata_buffer, '\0', ULP_METADATA_BUF_LEN);
/* Load the .ulp section into the metadata buffer. */
long len = Get_ULP_Section(ULP_METADATA_BUF_LEN, (void*)__ulp_metadata_buffer, path);
if (len < 0) {
/* Invalid. */
return (int) -len;
}
if (inject_lp_path(path, len)) {
return EINVALIDULP;
}
/* Trigger the livepatch. */
if ((ret = __ulp_apply_patch()) != 0) {
return ret;
}
/* Process instruction queue. */
if ((ret = insnq_interpret_from_lib()) != 0) {
return ret;
}
return 0;
}
int
gdb_ulp_revert(const char *path)
{
int ret;
/* Prepare the ULP metadata buffer. */
memset(__ulp_metadata_buffer, '\0', ULP_METADATA_BUF_LEN);
/* Load the .ulp section into the metadata buffer. */
long len = Get_ULP_REV_Section(ULP_METADATA_BUF_LEN, (void *)__ulp_metadata_buffer, path);
if (len < 0) {
/* Invalid. */
return (int) -len;
}
if (inject_lp_path(path, len)) {
return EINVALIDULP;
}
/* Trigger the livepatch. */
if ((ret = __ulp_apply_patch()) != 0) {
return ret;
}
/* Process instruction queue. */
if ((ret = insnq_interpret_from_lib()) != 0) {
return ret;
}
return 0;
}
#endif //ENABLE_GDB_INTERFACE
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