// SPDX-License-Identifier: GPL-2.0 /* * dm-init.c * Copyright (C) 2017 The Chromium OS Authors * * This file is released under the GPLv2. */ #include #include #include #include #include #include #define DM_MSG_PREFIX "init" #define DM_MAX_DEVICES 256 #define DM_MAX_TARGETS 256 #define DM_MAX_STR_SIZE 4096 static char *create; /* * Format: dm-mod.create=,,,,[,
+][;,,,,
[,
+]+] * Table format: * * See Documentation/device-mapper/dm-init.txt for dm-mod.create="..." format * details. */ struct dm_device { struct dm_ioctl dmi; struct dm_target_spec *table[DM_MAX_TARGETS]; char *target_args_array[DM_MAX_TARGETS]; struct list_head list; }; const char * const dm_allowed_targets[] __initconst = { "crypt", "delay", "linear", "snapshot-origin", "striped", "verity", }; static int __init dm_verify_target_type(const char *target) { unsigned int i; for (i = 0; i < ARRAY_SIZE(dm_allowed_targets); i++) { if (!strcmp(dm_allowed_targets[i], target)) return 0; } return -EINVAL; } static void __init dm_setup_cleanup(struct list_head *devices) { struct dm_device *dev, *tmp; unsigned int i; list_for_each_entry_safe(dev, tmp, devices, list) { list_del(&dev->list); for (i = 0; i < dev->dmi.target_count; i++) { kfree(dev->table[i]); kfree(dev->target_args_array[i]); } kfree(dev); } } /** * str_field_delimit - delimit a string based on a separator char. * @str: the pointer to the string to delimit. * @separator: char that delimits the field * * Find a @separator and replace it by '\0'. * Remove leading and trailing spaces. * Return the remainder string after the @separator. */ static char __init *str_field_delimit(char **str, char separator) { char *s; /* TODO: add support for escaped characters */ *str = skip_spaces(*str); s = strchr(*str, separator); /* Delimit the field and remove trailing spaces */ if (s) *s = '\0'; *str = strim(*str); return s ? ++s : NULL; } /** * dm_parse_table_entry - parse a table entry * @dev: device to store the parsed information. * @str: the pointer to a string with the format: * [, ...] * * Return the remainder string after the table entry, i.e, after the comma which * delimits the entry or NULL if reached the end of the string. */ static char __init *dm_parse_table_entry(struct dm_device *dev, char *str) { const unsigned int n = dev->dmi.target_count - 1; struct dm_target_spec *sp; unsigned int i; /* fields: */ char *field[4]; char *next; field[0] = str; /* Delimit first 3 fields that are separated by space */ for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { field[i + 1] = str_field_delimit(&field[i], ' '); if (!field[i + 1]) return ERR_PTR(-EINVAL); } /* Delimit last field that can be terminated by comma */ next = str_field_delimit(&field[i], ','); sp = kzalloc(sizeof(*sp), GFP_KERNEL); if (!sp) return ERR_PTR(-ENOMEM); dev->table[n] = sp; /* start_sector */ if (kstrtoull(field[0], 0, &sp->sector_start)) return ERR_PTR(-EINVAL); /* num_sector */ if (kstrtoull(field[1], 0, &sp->length)) return ERR_PTR(-EINVAL); /* target_type */ strscpy(sp->target_type, field[2], sizeof(sp->target_type)); if (dm_verify_target_type(sp->target_type)) { DMERR("invalid type \"%s\"", sp->target_type); return ERR_PTR(-EINVAL); } /* target_args */ dev->target_args_array[n] = kstrndup(field[3], DM_MAX_STR_SIZE, GFP_KERNEL); if (!dev->target_args_array[n]) return ERR_PTR(-ENOMEM); return next; } /** * dm_parse_table - parse "dm-mod.create=" table field * @dev: device to store the parsed information. * @str: the pointer to a string with the format: *
[,
+] */ static int __init dm_parse_table(struct dm_device *dev, char *str) { char *table_entry = str; while (table_entry) { DMDEBUG("parsing table \"%s\"", str); if (++dev->dmi.target_count > DM_MAX_TARGETS) { DMERR("too many targets %u > %d", dev->dmi.target_count, DM_MAX_TARGETS); return -EINVAL; } table_entry = dm_parse_table_entry(dev, table_entry); if (IS_ERR(table_entry)) { DMERR("couldn't parse table"); return PTR_ERR(table_entry); } } return 0; } /** * dm_parse_device_entry - parse a device entry * @dev: device to store the parsed information. * @str: the pointer to a string with the format: * name,uuid,minor,flags,table[; ...] * * Return the remainder string after the table entry, i.e, after the semi-colon * which delimits the entry or NULL if reached the end of the string. */ static char __init *dm_parse_device_entry(struct dm_device *dev, char *str) { /* There are 5 fields: name,uuid,minor,flags,table; */ char *field[5]; unsigned int i; char *next; field[0] = str; /* Delimit first 4 fields that are separated by comma */ for (i = 0; i < ARRAY_SIZE(field) - 1; i++) { field[i+1] = str_field_delimit(&field[i], ','); if (!field[i+1]) return ERR_PTR(-EINVAL); } /* Delimit last field that can be delimited by semi-colon */ next = str_field_delimit(&field[i], ';'); /* name */ strscpy(dev->dmi.name, field[0], sizeof(dev->dmi.name)); /* uuid */ strscpy(dev->dmi.uuid, field[1], sizeof(dev->dmi.uuid)); /* minor */ if (strlen(field[2])) { if (kstrtoull(field[2], 0, &dev->dmi.dev)) return ERR_PTR(-EINVAL); dev->dmi.flags |= DM_PERSISTENT_DEV_FLAG; } /* flags */ if (!strcmp(field[3], "ro")) dev->dmi.flags |= DM_READONLY_FLAG; else if (strcmp(field[3], "rw")) return ERR_PTR(-EINVAL); /* table */ if (dm_parse_table(dev, field[4])) return ERR_PTR(-EINVAL); return next; } /** * dm_parse_devices - parse "dm-mod.create=" argument * @devices: list of struct dm_device to store the parsed information. * @str: the pointer to a string with the format: * [;+] */ static int __init dm_parse_devices(struct list_head *devices, char *str) { unsigned long ndev = 0; struct dm_device *dev; char *device = str; DMDEBUG("parsing \"%s\"", str); while (device) { dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (!dev) return -ENOMEM; list_add_tail(&dev->list, devices); if (++ndev > DM_MAX_DEVICES) { DMERR("too many devices %lu > %d", ndev, DM_MAX_DEVICES); return -EINVAL; } device = dm_parse_device_entry(dev, device); if (IS_ERR(device)) { DMERR("couldn't parse device"); return PTR_ERR(device); } } return 0; } /** * dm_init_init - parse "dm-mod.create=" argument and configure drivers */ static int __init dm_init_init(void) { struct dm_device *dev; LIST_HEAD(devices); char *str; int r; if (!create) return 0; if (strlen(create) >= DM_MAX_STR_SIZE) { DMERR("Argument is too big. Limit is %d", DM_MAX_STR_SIZE); return -EINVAL; } str = kstrndup(create, DM_MAX_STR_SIZE, GFP_KERNEL); if (!str) return -ENOMEM; r = dm_parse_devices(&devices, str); if (r) goto out; DMINFO("waiting for all devices to be available before creating mapped devices"); wait_for_device_probe(); list_for_each_entry(dev, &devices, list) { if (dm_early_create(&dev->dmi, dev->table, dev->target_args_array)) break; } out: kfree(str); dm_setup_cleanup(&devices); return r; } late_initcall(dm_init_init); module_param(create, charp, 0); MODULE_PARM_DESC(create, "Create a mapped device in early boot");