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426311f440
The default sysfs path is always set to '/sys' unless the SYSFS_ROOT environment variable is defined. To address security concerns, secure_getenv() is used within util_path_sysfs() to protect against malicious values in SYSFS_ROOT. Additionally, constructing the sysfs path dynamically in an allocated buffer, rather than using a fixed-size buffer, helps prevent potential buffer overflows. These modifications also significantly improve testability by allowing sysfs read and write operations to be redirected to an alternative file path, which enables testing without affecting the active system state. Signed-off-by: Jan Polensky <japo@linux.ibm.com> Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com> Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
118 lines
2.8 KiB
C
118 lines
2.8 KiB
C
/*
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* ipl_tools - Linux for System z reipl and shutdown tools
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*
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* CCW device functions
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*
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* Copyright IBM Corp. 2008, 2017
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*
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* s390-tools is free software; you can redistribute it and/or modify
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* it under the terms of the MIT license. See LICENSE for details.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "lib/util_path.h"
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#include "lib/util_panic.h"
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#include "ipl_tools.h"
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/*
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* Look up for the device in /sys/devices/ hierarchy.
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*
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* path must be PATH_MAX large and the value will be replaced in place
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*/
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static int device_sysfs_path(const char *device, char *path, const size_t path_size)
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{
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util_assert(device != NULL, "Internal error: device is NULL");
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util_assert(path != NULL, "Internal error: path is NULL");
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util_assert(path_size == PATH_MAX, "Internal error: path_size is '%zu', but must be '%zu'",
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path_size, PATH_MAX);
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char *buf = util_path_sysfs("block/%s/device", device);
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if (!realpath(buf, path)) {
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free(buf);
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return -1;
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}
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free(buf);
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return 0;
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}
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/*
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* Check if the specified device number is a valid device number
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* which can be found in the /sys/bus/ccw/drivers/dasd-eckd/
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* structure.
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*
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* This does not work when booting from tape.
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*/
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int ccw_is_device(const char *busid)
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{
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static const char *const driver_paths[] = { "dasd-eckd", "virtio_ccw", "dasd-fba" };
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char *path;
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size_t i;
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for (i = 0; i < ARRAY_SIZE(driver_paths); i++) {
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path = util_path_sysfs("bus/ccw/drivers/%s/%s", driver_paths[i], busid);
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if (access(path, R_OK) == 0) {
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free(path);
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return 1;
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}
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free(path);
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}
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return 0;
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}
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/*
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* Check if the specified device is a valid virtio subchannel device
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*/
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int ccw_is_virtio_device(const char *device)
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{
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char path[PATH_MAX] = { '\0' };
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unsigned virtio = 0;
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char *path_pattern;
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if (device_sysfs_path(device, path, sizeof(path)) != 0)
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return -1;
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/*
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* The output has the following format:
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* /sys/devices/css0/0.0.0000/0.0.0000/virtio0/block/vda
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*/
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path_pattern = util_path_sysfs("devices/css0/%%*[0-9a-f.]/%%*[0-9a-f.]/virtio%%u");
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if (sscanf(path, path_pattern, &virtio) != 1) {
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free(path_pattern);
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return -1;
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}
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free(path_pattern);
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return 0;
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}
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/*
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* Return CCW Bus ID
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*/
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void ccw_busid_get(const char *device, char *busid)
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{
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char path[PATH_MAX] = { '\0' };
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char *path_pattern;
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if (device_sysfs_path(device, path, sizeof(path)) != 0)
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ERR_EXIT("Could not lookup device number for \"%s\"", device);
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/*
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* The output has the following format:
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* /sys/devices/css0/0.0.0119/0.0.3f19/block/dasda
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* /sys/devices/css0/0.0.0000/0.0.0000/virtio0/block/vda
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*/
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path_pattern = util_path_sysfs("devices/css0/%%*[0-9a-f.]/%%[0-9a-f.]");
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if (sscanf(path, path_pattern, busid) != 1) {
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free(path_pattern);
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ERR_EXIT("Could not lookup device number for \"%s\"", device);
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}
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free(path_pattern);
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return;
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}
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