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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Minios-devel] [UNIKRAFT PATCH v4 2/7] plat/xen: Add API for Xenstore messages
Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
Costin Lupu <costin.lupu@xxxxxxxxx> writes:
> Add the API needed for sending Xenstore messages. These functions
> are used by any client communicating with the Xenstore daemon.
>
> Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
> ---
> plat/xen/Makefile.uk | 2 +
> plat/xen/include/xenbus/xs.h | 282 ++++++++++++++++++
> plat/xen/xenbus/exportsyms.uk | 21 ++
> plat/xen/xenbus/xs.c | 674
> ++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 979 insertions(+)
> create mode 100644 plat/xen/include/xenbus/xs.h
> create mode 100644 plat/xen/xenbus/exportsyms.uk
> create mode 100644 plat/xen/xenbus/xs.c
>
> diff --git a/plat/xen/Makefile.uk b/plat/xen/Makefile.uk
> index 2703a54..5578194 100644
> --- a/plat/xen/Makefile.uk
> +++ b/plat/xen/Makefile.uk
> @@ -74,10 +74,12 @@ LIBXENPLAT_SRCS-y +=
> $(LIBXENPLAT_BASE)/events.c
> LIBXENPLAT_SRCS-y += $(LIBXENPLAT_BASE)/gnttab.c
>
> ifeq ($(CONFIG_XEN_XENBUS),y)
> +LIBXENBUS_EXPORTS = $(LIBXENPLAT_BASE)/xenbus/exportsyms.uk
> LIBXENBUS_ASFLAGS-y += $(LIBXENPLAT_ASFLAGS-y)
> LIBXENBUS_ASINCLUDES-y += $(LIBXENPLAT_ASINCLUDES-y)
> LIBXENBUS_CFLAGS-y += $(LIBXENPLAT_CFLAGS-y)
> LIBXENBUS_CINCLUDES-y += $(LIBXENPLAT_CINCLUDES-y)
> LIBXENBUS_SRCS-y += $(LIBXENPLAT_BASE)/xenbus/xenbus.c
> LIBXENBUS_SRCS-y += $(LIBXENPLAT_BASE)/xenbus/xs_comms.c
> +LIBXENBUS_SRCS-y += $(LIBXENPLAT_BASE)/xenbus/xs.c
> endif
> diff --git a/plat/xen/include/xenbus/xs.h b/plat/xen/include/xenbus/xs.h
> new file mode 100644
> index 0000000..afa1ce2
> --- /dev/null
> +++ b/plat/xen/include/xenbus/xs.h
> @@ -0,0 +1,282 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
> +/*
> + * Authors: Costin Lupu <costin.lupu@xxxxxxxxx>
> + *
> + * Copyright (c) 2018, NEC Europe Ltd., NEC Corporation. All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + *
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of the copyright holder nor the names of its
> + * contributors may be used to endorse or promote products derived from
> + * this software without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
> IS"
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
> + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
> + * POSSIBILITY OF SUCH DAMAGE.
> + *
> + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> + */
> +/* Xenstore API */
> +/*
> + * TODO The intention for this API is to be used by applications as well.
> + * Therefore, all data allocated by this API for external use must be free'd
> + * calling 'free' function (and not uk_xb_free). This is the reason why such
> + * data is allocated with 'malloc'/'calloc'.
> + */
> +
> +#ifndef __XS_H__
> +#define __XS_H__
> +
> +#include <xenbus/xenbus.h>
> +
> +
> +/*
> + * Read the value associated with a path.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param node Xenstore subdirectory
> + * @return On success, returns a malloc'd copy of the value. On error,
> returns
> + * a negative error number which should be checked using PTRISERR.
> + */
> +char *xs_read(xenbus_transaction_t xbt, const char *path, const char *node);
> +
> +/*
> + * Associates a value with a path.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param node Xenstore subdirectory (optional)
> + * @param value Xenstore value
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_write(xenbus_transaction_t xbt, const char *path, const char *node,
> + const char *value);
> +
> +/*
> + * List the contents of a directory.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore directory path
> + * @param node Xenstore subdirectory (optional)
> + * @return On success, returns a malloc'd array of pointers to strings. The
> + * array is NULL terminated. The caller should free only the array. On error,
> + * returns a negative error number which should be checked using PTRISERR.
> + * May block.
> + */
> +char **xs_ls(xenbus_transaction_t xbt, const char *path);
> +
> +/*
> + * Removes the value associated with a path.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_rm(xenbus_transaction_t xbt, const char *path);
> +
> +/*
> + * Xenstore permissions
> + */
> +enum xs_perm {
> + XS_PERM_NONE = 0x0,
> + XS_PERM_READ = 0x1,
> + XS_PERM_WRITE = 0x2,
> + XS_PERM_BOTH = XS_PERM_WRITE | XS_PERM_READ
> +};
> +
> +/*
> + * Converts a character to corresponding permission value.
> + *
> + * @param c Permission character
> + * @param perm Permission value
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_char_to_perm(char c, enum xs_perm *perm);
> +
> +/*
> + * Converts a permission value to corresponding character.
> + *
> + * @param perm Permission value
> + * @param c Permission character
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_perm_to_char(enum xs_perm perm, char *c);
> +
> +/*
> + * Extracts domid and permission value out of a permission string.
> + *
> + * @param str Permission string
> + * @param domid Domain ID
> + * @param perm Permission value
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_str_to_perm(const char *str, domid_t *domid, enum xs_perm *perm);
> +
> +/*
> + * Returns a permission string from domid and permission value.
> + *
> + * @param domid Domain ID
> + * @param perm Permission value
> + * @return On success, returns a malloc'd string. On error, returns a
> negative
> + * error number which should be checked using PTRISERR.
> + */
> +char *xs_perm_to_str(domid_t domid, enum xs_perm perm);
> +
> +/*
> + * Xenstore ACL
> + */
> +struct xs_acl_entry {
> + domid_t domid;
> + enum xs_perm perm;
> +};
> +
> +struct xs_acl {
> + domid_t ownerid;
> + enum xs_perm others_perm;
> + int entries_num;
> + struct xs_acl_entry entries[];
> +};
> +
> +/*
> + * Returns the ACL for input path.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @return On success, returns a malloc'd ACL. On error, returns a
> + * negative error number which should be checked using PTRISERR.
> + */
> +struct xs_acl *xs_get_acl(xenbus_transaction_t xbt, const char *path);
> +
> +/*
> + * Sets ACL for input path.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param acl New ACL
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_set_acl(xenbus_transaction_t xbt, const char *path, struct xs_acl
> *acl);
> +
> +/*
> + * Reads permissions for input path and domid.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param domid Domain ID
> + * @param perm Permission value
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_get_perm(xenbus_transaction_t xbt, const char *path,
> + domid_t domid, enum xs_perm *perm);
> +
> +/*
> + * Sets permissions for input path and domid.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param domid Domain ID
> + * @param perm Permission value
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_set_perm(xenbus_transaction_t xbt, const char *path,
> + domid_t domid, enum xs_perm perm);
> +
> +/*
> + * Deletes permissions for domid.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param domid Domain ID
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_del_perm(xenbus_transaction_t xbt, const char *path,
> + domid_t domid);
> +
> +/*
> + * Start a xenbus transaction. Returns the transaction in xbt on
> + * success or an error number otherwise.
> + *
> + * @param xbt Address for returning the Xenbus transaction id
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_transaction_start(xenbus_transaction_t *xbt);
> +
> +/*
> + * End a xenbus transaction. Returns non-zero on failure.
> + * Parameter abort says whether the transaction should be aborted.
> + * Returns 1 in *retry iff the transaction should be retried.
> + *
> + * @param xbt Xenbus transaction id
> + * @param abort Non-zero if transaction should be aborted
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_transaction_end(xenbus_transaction_t xbt, int abort);
> +
> +/*
> + * Sends a debug message to the Xenstore daemon for writing it in the debug
> log
> + *
> + * @param msg The logged message
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_debug_msg(const char *msg);
> +
> +/*
> + * Read path and parse it as an integer.
> + *
> + * @param xbt Xenbus transaction id
> + * @param path Xenstore path
> + * @param value Returned int value
> + * @return 0 on success, a negative errno value on error.
> + */
> +int xs_read_integer(xenbus_transaction_t xbt, const char *path, int *value);
> +
> +/*
> + * Contraction of sscanf and xs_read(node/path).
> + *
> + * @param xbt Xenbus transaction id
> + * @param dir Xenstore directory
> + * @param node Xenstore directory entry
> + * @param fmt Path format string
> + * @return On success returns the number of input items successfully matched
> + * and assigned. On error returns a negative errno value.
> + */
> +int xs_scanf(xenbus_transaction_t xbt, const char *dir, const char *node,
> + const char *fmt, ...) __scanf(4, 5);
> +
> +/*
> + * Contraction of sprintf and xs_write(node/path).
> + *
> + * @param xbt Xenbus transaction id
> + * @param dir Xenstore directory
> + * @param node Xenstore directory entry
> + * @param fmt Path format string
> + * @return On success returns the number of the number of characters printed.
> + * On error returns a negative errno value.
> + */
> +int xs_printf(xenbus_transaction_t xbt, const char *dir, const char *node,
> + const char *fmt, ...) __printf(4, 5);
> +
> +/*
> + * Utility function to figure out our domain id
> + *
> + * @return Our domain id
> + */
> +domid_t xs_get_self_id(void);
> +
> +#endif /* __XS_H__ */
> diff --git a/plat/xen/xenbus/exportsyms.uk b/plat/xen/xenbus/exportsyms.uk
> new file mode 100644
> index 0000000..5d9729e
> --- /dev/null
> +++ b/plat/xen/xenbus/exportsyms.uk
> @@ -0,0 +1,21 @@
> +# Xenstore API
> +xs_read
> +xs_write
> +xs_ls
> +xs_rm
> +xs_char_to_perm
> +xs_perm_to_char
> +xs_str_to_perm
> +xs_perm_to_str
> +xs_get_acl
> +xs_set_acl
> +xs_get_perm
> +xs_set_perm
> +xs_del_perm
> +xs_transaction_start
> +xs_transaction_end
> +xs_debug_msg
> +xs_read_integer
> +xs_scanf
> +xs_printf
> +xs_get_self_id
> diff --git a/plat/xen/xenbus/xs.c b/plat/xen/xenbus/xs.c
> new file mode 100644
> index 0000000..fad7d9d
> --- /dev/null
> +++ b/plat/xen/xenbus/xs.c
> @@ -0,0 +1,674 @@
> +/* SPDX-License-Identifier: BSD-3-Clause */
> +/*
> + * Authors: Steven Smith (sos22@xxxxxxxxx)
> + * Grzegorz Milos (gm281@xxxxxxxxx)
> + * John D. Ramsdell
> + * Costin Lupu <costin.lupu@xxxxxxxxx>
> + *
> + * Copyright (c) 2006, Cambridge University
> + * 2018, NEC Europe Ltd., NEC Corporation. All rights reserved.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + *
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of the copyright holder nor the names of its
> + * contributors may be used to endorse or promote products derived from
> + * this software without specific prior written permission.
> + *
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
> IS"
> + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
> + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
> + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
> + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
> + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
> + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
> + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
> + * POSSIBILITY OF SUCH DAMAGE.
> + *
> + * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
> + */
> +/*
> + * Ported from Mini-OS xenbus.c
> + */
> +
> +#include <stdlib.h>
> +#include <stdio.h>
> +#include <string.h>
> +#include <stdint.h>
> +#include <stdarg.h>
> +#include <uk/errptr.h>
> +#include <xen/io/xs_wire.h>
> +#include <xenbus/xs.h>
> +#include "xs_comms.h"
> +
> +
> +/* Helper macros for initializing xs requests from strings */
> +#define XS_IOVEC_STR_NULL(str) \
> + ((struct xs_iovec) { str, strlen(str) + 1 })
> +#define XS_IOVEC_STR(str) \
> + ((struct xs_iovec) { str, strlen(str) })
> +
> +
> +/* Common function used for sending requests when replies aren't handled */
> +static inline int xs_msg(enum xsd_sockmsg_type type, xenbus_transaction_t
> xbt,
> + struct xs_iovec *reqs, int reqs_num)
> +{
> + return xs_msg_reply(type, xbt, reqs, reqs_num, NULL);
> +}
> +
> +char *xs_read(xenbus_transaction_t xbt, const char *path, const char *node)
> +{
> + struct xs_iovec req, rep;
> + char *fullpath, *value;
> + int err;
> +
> + if (path == NULL)
> + return ERR2PTR(-EINVAL);
> +
> + if (node != NULL) {
> + err = asprintf(&fullpath, "%s/%s", path, node);
> + if (err < 0) {
> + value = ERR2PTR(-ENOMEM);
> + goto out;
> + }
> + } else
> + fullpath = (char *) path;
> +
> + req = XS_IOVEC_STR_NULL(fullpath);
> + err = xs_msg_reply(XS_READ, xbt, &req, 1, &rep);
> + if (err == 0)
> + value = rep.data;
> + else
> + value = ERR2PTR(err);
> +
> + if (node != NULL)
> + free(fullpath);
> +out:
> + return value;
> +}
> +
> +int xs_write(xenbus_transaction_t xbt, const char *path, const char *node,
> + const char *value)
> +{
> + struct xs_iovec req[2];
> + char *fullpath;
> + int err;
> +
> + if (path == NULL || value == NULL)
> + return -EINVAL;
> +
> + if (node != NULL) {
> + err = asprintf(&fullpath, "%s/%s", path, node);
> + if (err < 0) {
> + err = -ENOMEM;
> + goto out;
> + }
> + } else
> + fullpath = (char *) path;
> +
> + req[0] = XS_IOVEC_STR_NULL(fullpath);
> + req[1] = XS_IOVEC_STR((char *) value);
> +
> + err = xs_msg(XS_WRITE, xbt, req, ARRAY_SIZE(req));
> +
> + if (node != NULL)
> + free(fullpath);
> +out:
> + return err;
> +}
> +
> +/* Returns an array of strings out of the serialized reply */
> +static char **reply_to_string_array(struct xs_iovec *rep, int *size)
> +{
> + int strings_num, offs, i;
> + char *rep_strings, *strings, **res = NULL;
> +
> + rep_strings = rep->data;
> +
> + /* count the strings */
> + for (offs = strings_num = 0; offs < (int) rep->len; offs++)
> + strings_num += (rep_strings[offs] == 0);
> +
> + /* one alloc for both string addresses and contents */
> + res = malloc((strings_num + 1) * sizeof(char *) + rep->len);
> + if (!res)
> + return ERR2PTR(-ENOMEM);
> +
> + /* copy the strings to the end of the array */
> + strings = (char *) &res[strings_num + 1];
> + memcpy(strings, rep_strings, rep->len);
> +
> + /* fill the string array */
> + for (offs = i = 0; i < strings_num; i++) {
> + char *string = strings + offs;
> + int string_len = strlen(string);
> +
> + res[i] = string;
> +
> + offs += string_len + 1;
> + }
> + res[i] = NULL;
> +
> + if (size)
> + *size = strings_num;
> +
> + return res;
> +}
> +
> +char **xs_ls(xenbus_transaction_t xbt, const char *path)
> +{
> + struct xs_iovec req, rep;
> + char **res = NULL;
> + int err;
> +
> + if (path == NULL)
> + return ERR2PTR(-EINVAL);
> +
> + req = XS_IOVEC_STR_NULL((char *) path);
> + err = xs_msg_reply(XS_DIRECTORY, xbt, &req, 1, &rep);
> + if (err)
> + return ERR2PTR(err);
> +
> + res = reply_to_string_array(&rep, NULL);
> + free(rep.data);
> +
> + return res;
> +}
> +
> +int xs_rm(xenbus_transaction_t xbt, const char *path)
> +{
> + struct xs_iovec req;
> +
> + if (path == NULL)
> + return -EINVAL;
> +
> + req = XS_IOVEC_STR_NULL((char *) path);
> +
> + return xs_msg(XS_RM, xbt, &req, 1);
> +}
> +
> +/*
> + * Permissions
> + */
> +
> +static const char xs_perm_tbl[] = {
> + [XS_PERM_NONE] = 'n',
> + [XS_PERM_READ] = 'r',
> + [XS_PERM_WRITE] = 'w',
> + [XS_PERM_BOTH] = 'b',
> +};
> +
> +int xs_char_to_perm(char c, enum xs_perm *perm)
> +{
> + int err = -EINVAL;
> +
> + if (perm == NULL)
> + goto out;
> +
> + for (int i = 0; i < (int) ARRAY_SIZE(xs_perm_tbl); i++) {
> + if (c == xs_perm_tbl[i]) {
> + *perm = i;
> + err = 0;
> + break;
> + }
> + }
> +
> +out:
> + return err;
> +}
> +
> +int xs_perm_to_char(enum xs_perm perm, char *c)
> +{
> + if (c == NULL || perm >= ARRAY_SIZE(xs_perm_tbl))
> + return -EINVAL;
> +
> + *c = xs_perm_tbl[perm];
> +
> + return 0;
> +}
> +
> +int xs_str_to_perm(const char *str, domid_t *domid, enum xs_perm *perm)
> +{
> + int err = 0;
> +
> + if (str == NULL || domid == NULL || perm == NULL) {
> + err = -EINVAL;
> + goto out;
> + }
> +
> + err = xs_char_to_perm(str[0], perm);
> + if (err)
> + goto out;
> +
> + *domid = (domid_t) strtoul(&str[1], NULL, 10);
> +
> +out:
> + return err;
> +}
> +
> +#define PERM_MAX_SIZE 32
> +char *xs_perm_to_str(domid_t domid, enum xs_perm perm)
> +{
> + int err = 0;
> + char permc, value[PERM_MAX_SIZE];
> +
> + err = xs_perm_to_char(perm, &permc);
> + if (err)
> + return NULL;
> +
> + snprintf(value, PERM_MAX_SIZE, "%c%hu", permc, domid);
> +
> + return strdup(value);
> +}
> +
> +/*
> + * Returns the ACL for input path. An extra number of empty entries may be
> + * requested if caller intends to extend the list.
> + */
> +static struct xs_acl *__xs_get_acl(xenbus_transaction_t xbt, const char
> *path,
> + int extra)
> +{
> + struct xs_acl *acl = NULL;
> + struct xs_iovec req, rep;
> + char **values;
> + int values_num, err;
> +
> + if (path == NULL) {
> + err = EINVAL;
> + goto out;
> + }
> +
> + req = XS_IOVEC_STR_NULL((char *) path);
> + err = xs_msg_reply(XS_GET_PERMS, xbt, &req, 1, &rep);
> + if (err)
> + goto out;
> +
> + values = reply_to_string_array(&rep, &values_num);
> + free(rep.data);
> + if (PTRISERR(values)) {
> + err = PTR2ERR(values);
> + goto out;
> + }
> +
> + acl = malloc(sizeof(struct xs_acl) +
> + (values_num + extra) * sizeof(struct xs_acl_entry));
> + if (acl == NULL) {
> + err = ENOMEM;
> + goto out_values;
> + }
> +
> + /* set owner id and permissions for others */
> + err = xs_str_to_perm(values[0],
> + &acl->ownerid, &acl->others_perm);
> + if (err)
> + goto out_values;
> +
> + /* set ACL entries */
> + acl->entries_num = values_num - 1;
> + for (int i = 0; i < acl->entries_num; i++) {
> + err = xs_str_to_perm(values[i + 1],
> + &acl->entries[i].domid, &acl->entries[i].perm);
> + if (err)
> + goto out_values;
> + }
> +
> +out_values:
> + free(values);
> +out:
> + if (err) {
> + if (acl)
> + free(acl);
> + acl = ERR2PTR(err);
> + }
> + return acl;
> +}
> +
> +struct xs_acl *xs_get_acl(xenbus_transaction_t xbt, const char *path)
> +{
> + return __xs_get_acl(xbt, path, 0);
> +}
> +
> +int xs_set_acl(xenbus_transaction_t xbt, const char *path, struct xs_acl
> *acl)
> +{
> + struct xs_iovec req[2 + acl->entries_num];
> + char *s;
> + int i, err;
> +
> + if (path == NULL || acl == NULL) {
> + err = -EINVAL;
> + goto out;
> + }
> +
> + req[0] = XS_IOVEC_STR_NULL((char *) path);
> +
> + s = xs_perm_to_str(acl->ownerid, acl->others_perm);
> + if (s == NULL) {
> + err = -EINVAL;
> + goto out;
> + }
> +
> + req[1] = XS_IOVEC_STR_NULL(s);
> +
> + for (i = 0; i < acl->entries_num; i++) {
> + struct xs_acl_entry *acle = &acl->entries[i];
> +
> + s = xs_perm_to_str(acle->domid, acle->perm);
> + if (s == NULL) {
> + err = -EINVAL;
> + goto out_req;
> + }
> +
> + req[i + 2] = XS_IOVEC_STR_NULL(s);
> + }
> +
> + err = xs_msg(XS_SET_PERMS, xbt, req, ARRAY_SIZE(req));
> +
> +out_req:
> + for (i--; i > 0; i--)
> + free(req[i].data);
> +out:
> + return err;
> +}
> +
> +int xs_get_perm(xenbus_transaction_t xbt, const char *path,
> + domid_t domid, enum xs_perm *perm)
> +{
> + struct xs_acl *acl;
> + int err = 0;
> +
> + if (perm == NULL) {
> + err = -EINVAL;
> + goto out;
> + }
> +
> + acl = xs_get_acl(xbt, path);
> + if (PTRISERR(acl)) {
> + err = PTR2ERR(acl);
> + goto out;
> + }
> +
> + if (acl->ownerid == domid) {
> + *perm = XS_PERM_BOTH;
> + goto out_acl;
> + }
> +
> + for (int i = 0; i < acl->entries_num; i++) {
> + struct xs_acl_entry *acle = &acl->entries[i];
> +
> + if (acle->domid == domid) {
> + *perm = acle->perm;
> + goto out_acl;
> + }
> + }
> +
> + *perm = acl->others_perm;
> +
> +out_acl:
> + free(acl);
> +out:
> + return err;
> +}
> +
> +static int acl_find_entry_index(struct xs_acl *acl, domid_t domid)
> +{
> + struct xs_acl_entry *acle;
> + int i;
> +
> + if (acl->ownerid == domid)
> + /*
> + * let's say the function isn't called correctly considering
> + * that the owner domain has all the rights, all the time
> + */
> + return -EINVAL;
> +
> + for (i = 0; i < acl->entries_num; i++) {
> + acle = &acl->entries[i];
> + if (acle->domid == domid)
> + break;
> + }
> +
> + if (i == acl->entries_num)
> + /* no entry found for domid */
> + return -ENOENT;
> +
> + return i;
> +}
> +
> +int xs_set_perm(xenbus_transaction_t xbt, const char *path,
> + domid_t domid, enum xs_perm perm)
> +{
> + struct xs_acl *acl;
> + struct xs_acl_entry *acle;
> + int err, idx;
> +
> + UK_ASSERT(xbt != XBT_NIL);
> +
> + /* one extra entry in case a new one will be added */
> + acl = __xs_get_acl(xbt, path, 1);
> + if (PTRISERR(acl)) {
> + err = PTR2ERR(acl);
> + goto out;
> + }
> +
> + idx = acl_find_entry_index(acl, domid);
> + if (idx == -ENOENT) {
> + /* new entry */
> + acle = &acl->entries[acl->entries_num];
> + acle->domid = domid;
> + acle->perm = perm;
> + acl->entries_num++;
> +
> + } else if (idx < 0) {
> + /* some other error */
> + err = idx;
> + goto out_acl;
> +
> + } else {
> + /* update entry */
> + acle = &acl->entries[idx];
> + acle->perm = perm;
> + }
> +
> + err = xs_set_acl(xbt, path, acl);
> +
> +out_acl:
> + free(acl);
> +out:
> + return err;
> +}
> +
> +int xs_del_perm(xenbus_transaction_t xbt, const char *path,
> + domid_t domid)
> +{
> + struct xs_acl *acl;
> + int idx, err = 0;
> +
> + UK_ASSERT(xbt != XBT_NIL);
> +
> + acl = __xs_get_acl(xbt, path, 0);
> + if (PTRISERR(acl)) {
> + err = PTR2ERR(acl);
> + goto out;
> + }
> +
> + idx = acl_find_entry_index(acl, domid);
> + if (idx < 0) {
> + err = idx;
> + goto out_acl;
> + }
> +
> + /* remove entry */
> + acl->entries_num--;
> + memmove(&acl->entries[idx], &acl->entries[idx + 1],
> + (acl->entries_num - idx) * sizeof(struct xs_acl_entry));
> +
> + err = xs_set_acl(xbt, path, acl);
> +
> +out_acl:
> + free(acl);
> +out:
> + return err;
> +}
> +
> +/*
> + * Transactions
> + */
> +
> +int xs_transaction_start(xenbus_transaction_t *xbt)
> +{
> + /*
> + * xenstored becomes angry if you send a length 0 message,
> + * so just shove a nul terminator on the end
> + */
> + struct xs_iovec req, rep;
> + int err;
> +
> + if (xbt == NULL)
> + return -EINVAL;
> +
> + req = XS_IOVEC_STR_NULL("");
> + err = xs_msg_reply(XS_TRANSACTION_START, 0, &req, 1, &rep);
> + if (err)
> + return err;
> +
> + *xbt = strtoul(rep.data, NULL, 10);
> + free(rep.data);
> +
> + return err;
> +}
> +
> +int xs_transaction_end(xenbus_transaction_t xbt, int abort)
> +{
> + struct xs_iovec req;
> +
> + req.data = abort ? "F" : "T";
> + req.len = 2;
> +
> + return xs_msg(XS_TRANSACTION_END, xbt, &req, 1);
> +}
> +
> +/*
> + * Misc
> + */
> +
> +/* Send a debug message to xenbus. Can block. */
> +int xs_debug_msg(const char *msg)
> +{
> + struct xs_iovec req[3], rep;
> + int err;
> +
> + if (msg == NULL)
> + return -EINVAL;
> +
> + req[0] = XS_IOVEC_STR_NULL("print");
> + req[1] = XS_IOVEC_STR((char *) msg);
> + req[2] = XS_IOVEC_STR_NULL("");
> +
> + err = xs_msg_reply(XS_DEBUG, XBT_NIL, req, ARRAY_SIZE(req), &rep);
> + if (err)
> + goto out;
> +
> + uk_printd(DLVL_EXTRA,
> + "Got a debug reply %s\n", (char *) rep.data);
> + free(rep.data);
> +
> +out:
> + return err;
> +}
> +
> +int xs_read_integer(xenbus_transaction_t xbt, const char *path, int *value)
> +{
> + char *value_str;
> +
> + if (path == NULL || value == NULL)
> + return -EINVAL;
> +
> + value_str = xs_read(xbt, path, NULL);
> + if (PTRISERR(value_str))
> + return PTR2ERR(value_str);
> +
> + *value = atoi(value_str);
> +
> + free(value_str);
> +
> + return 0;
> +}
> +
> +int xs_scanf(xenbus_transaction_t xbt, const char *dir, const char *node,
> + const char *fmt, ...)
> +{
> + char *val;
> + va_list args;
> + int err = 0;
> +
> + if (fmt == NULL)
> + return -EINVAL;
> +
> + val = xs_read(xbt, dir, node);
> + if (PTRISERR(val)) {
> + err = PTR2ERR(val);
> + goto out;
> + }
> +
> + va_start(args, fmt);
> + err = vsscanf(val, fmt, args);
> + va_end(args);
> +
> + free(val);
> +
> +out:
> + return err;
> +}
> +
> +int xs_printf(xenbus_transaction_t xbt, const char *dir, const char *node,
> + const char *fmt, ...)
> +{
> +#define VAL_SIZE 256
> + char val[VAL_SIZE];
> + va_list args;
> + int err = 0, _err;
> +
> + if (fmt == NULL)
> + return -EINVAL;
> +
> + va_start(args, fmt);
> + _err = vsnprintf(val, VAL_SIZE, fmt, args);
> + va_end(args);
> +
> + /* send to Xenstore if vsnprintf was successful */
> + if (_err > 0)
> + err = xs_write(xbt, dir, node, val);
> +
> + /*
> + * if message sent to Xenstore was successful,
> + * return the number of characters
> + */
> + if (err == 0)
> + err = _err;
> +
> + return err;
> +}
> +
> +domid_t xs_get_self_id(void)
> +{
> + char *domid_str;
> + domid_t domid;
> +
> + domid_str = xs_read(XBT_NIL, "domid", NULL);
> + if (PTRISERR(domid_str))
> + UK_CRASH("Error reading domain id.");
> +
> + domid = (domid_t) strtoul(domid_str, NULL, 10);
> +
> + free(domid_str);
> +
> + return domid;
> +}
> --
> 2.11.0
>
--
Yuri Volchkov
Software Specialist
NEC Europe Ltd
Kurfürsten-Anlage 36
D-69115 Heidelberg
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