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![Luo Jiaxing](/assets/img/avatar_default.png)
We found the following warning when build kernel with W=1: fs/fs_parser.c:192:5: warning: no previous prototype for `fs_param_bad_value' [-Wmissing-prototypes] int fs_param_bad_value(struct p_log *log, struct fs_parameter *param) ^ CC drivers/usb/gadget/udc/snps_udc_core.o And no header file define a prototype for this function, so we should mark it as static. Signed-off-by: Luo Jiaxing <luojiaxing@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Link: https://lkml.kernel.org/r/1601293463-25763-1-git-send-email-luojiaxing@huawei.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
385 lines
10 KiB
C
385 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* Filesystem parameter parser.
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*
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* Copyright (C) 2018 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <linux/export.h>
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#include <linux/fs_context.h>
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#include <linux/fs_parser.h>
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#include <linux/slab.h>
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#include <linux/security.h>
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#include <linux/namei.h>
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#include "internal.h"
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static const struct constant_table bool_names[] = {
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{ "0", false },
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{ "1", true },
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{ "false", false },
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{ "no", false },
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{ "true", true },
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{ "yes", true },
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{ },
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};
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static const struct constant_table *
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__lookup_constant(const struct constant_table *tbl, const char *name)
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{
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for ( ; tbl->name; tbl++)
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if (strcmp(name, tbl->name) == 0)
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return tbl;
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return NULL;
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}
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/**
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* lookup_constant - Look up a constant by name in an ordered table
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* @tbl: The table of constants to search.
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* @name: The name to look up.
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* @not_found: The value to return if the name is not found.
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*/
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int lookup_constant(const struct constant_table *tbl, const char *name, int not_found)
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{
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const struct constant_table *p = __lookup_constant(tbl, name);
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return p ? p->value : not_found;
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}
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EXPORT_SYMBOL(lookup_constant);
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static inline bool is_flag(const struct fs_parameter_spec *p)
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{
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return p->type == NULL;
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}
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static const struct fs_parameter_spec *fs_lookup_key(
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const struct fs_parameter_spec *desc,
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struct fs_parameter *param, bool *negated)
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{
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const struct fs_parameter_spec *p, *other = NULL;
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const char *name = param->key;
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bool want_flag = param->type == fs_value_is_flag;
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*negated = false;
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for (p = desc; p->name; p++) {
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if (strcmp(p->name, name) != 0)
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continue;
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if (likely(is_flag(p) == want_flag))
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return p;
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other = p;
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}
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if (want_flag) {
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if (name[0] == 'n' && name[1] == 'o' && name[2]) {
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for (p = desc; p->name; p++) {
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if (strcmp(p->name, name + 2) != 0)
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continue;
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if (!(p->flags & fs_param_neg_with_no))
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continue;
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*negated = true;
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return p;
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}
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}
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}
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return other;
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}
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/*
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* fs_parse - Parse a filesystem configuration parameter
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* @fc: The filesystem context to log errors through.
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* @desc: The parameter description to use.
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* @param: The parameter.
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* @result: Where to place the result of the parse
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*
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* Parse a filesystem configuration parameter and attempt a conversion for a
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* simple parameter for which this is requested. If successful, the determined
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* parameter ID is placed into @result->key, the desired type is indicated in
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* @result->t and any converted value is placed into an appropriate member of
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* the union in @result.
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*
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* The function returns the parameter number if the parameter was matched,
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* -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that
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* unknown parameters are okay and -EINVAL if there was a conversion issue or
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* the parameter wasn't recognised and unknowns aren't okay.
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*/
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int __fs_parse(struct p_log *log,
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const struct fs_parameter_spec *desc,
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struct fs_parameter *param,
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struct fs_parse_result *result)
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{
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const struct fs_parameter_spec *p;
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result->uint_64 = 0;
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p = fs_lookup_key(desc, param, &result->negated);
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if (!p)
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return -ENOPARAM;
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if (p->flags & fs_param_deprecated)
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warn_plog(log, "Deprecated parameter '%s'", param->key);
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/* Try to turn the type we were given into the type desired by the
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* parameter and give an error if we can't.
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*/
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if (is_flag(p)) {
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if (param->type != fs_value_is_flag)
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return inval_plog(log, "Unexpected value for '%s'",
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param->key);
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result->boolean = !result->negated;
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} else {
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int ret = p->type(log, p, param, result);
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if (ret)
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return ret;
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}
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return p->opt;
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}
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EXPORT_SYMBOL(__fs_parse);
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/**
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* fs_lookup_param - Look up a path referred to by a parameter
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* @fc: The filesystem context to log errors through.
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* @param: The parameter.
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* @want_bdev: T if want a blockdev
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* @_path: The result of the lookup
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*/
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int fs_lookup_param(struct fs_context *fc,
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struct fs_parameter *param,
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bool want_bdev,
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struct path *_path)
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{
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struct filename *f;
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unsigned int flags = 0;
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bool put_f;
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int ret;
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switch (param->type) {
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case fs_value_is_string:
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f = getname_kernel(param->string);
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if (IS_ERR(f))
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return PTR_ERR(f);
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put_f = true;
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break;
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case fs_value_is_filename:
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f = param->name;
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put_f = false;
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break;
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default:
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return invalf(fc, "%s: not usable as path", param->key);
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}
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f->refcnt++; /* filename_lookup() drops our ref. */
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ret = filename_lookup(param->dirfd, f, flags, _path, NULL);
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if (ret < 0) {
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errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);
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goto out;
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}
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if (want_bdev &&
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!S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) {
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path_put(_path);
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_path->dentry = NULL;
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_path->mnt = NULL;
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errorf(fc, "%s: Non-blockdev passed as '%s'",
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param->key, f->name);
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ret = -ENOTBLK;
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}
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out:
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if (put_f)
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putname(f);
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return ret;
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}
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EXPORT_SYMBOL(fs_lookup_param);
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static int fs_param_bad_value(struct p_log *log, struct fs_parameter *param)
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{
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return inval_plog(log, "Bad value for '%s'", param->key);
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}
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int fs_param_is_bool(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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int b;
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if (param->type != fs_value_is_string)
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return fs_param_bad_value(log, param);
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b = lookup_constant(bool_names, param->string, -1);
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if (b == -1)
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return fs_param_bad_value(log, param);
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result->boolean = b;
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_bool);
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int fs_param_is_u32(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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int base = (unsigned long)p->data;
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if (param->type != fs_value_is_string ||
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kstrtouint(param->string, base, &result->uint_32) < 0)
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return fs_param_bad_value(log, param);
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_u32);
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int fs_param_is_s32(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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if (param->type != fs_value_is_string ||
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kstrtoint(param->string, 0, &result->int_32) < 0)
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return fs_param_bad_value(log, param);
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_s32);
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int fs_param_is_u64(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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if (param->type != fs_value_is_string ||
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kstrtoull(param->string, 0, &result->uint_64) < 0)
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return fs_param_bad_value(log, param);
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_u64);
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int fs_param_is_enum(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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const struct constant_table *c;
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if (param->type != fs_value_is_string)
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return fs_param_bad_value(log, param);
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c = __lookup_constant(p->data, param->string);
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if (!c)
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return fs_param_bad_value(log, param);
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result->uint_32 = c->value;
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_enum);
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int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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if (param->type != fs_value_is_string || !*param->string)
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return fs_param_bad_value(log, param);
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_string);
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int fs_param_is_blob(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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if (param->type != fs_value_is_blob)
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return fs_param_bad_value(log, param);
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_blob);
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int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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switch (param->type) {
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case fs_value_is_string:
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if (kstrtouint(param->string, 0, &result->uint_32) < 0)
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break;
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if (result->uint_32 <= INT_MAX)
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return 0;
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break;
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case fs_value_is_file:
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result->uint_32 = param->dirfd;
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if (result->uint_32 <= INT_MAX)
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return 0;
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break;
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default:
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break;
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}
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return fs_param_bad_value(log, param);
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}
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EXPORT_SYMBOL(fs_param_is_fd);
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int fs_param_is_blockdev(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_blockdev);
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int fs_param_is_path(struct p_log *log, const struct fs_parameter_spec *p,
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struct fs_parameter *param, struct fs_parse_result *result)
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{
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return 0;
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}
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EXPORT_SYMBOL(fs_param_is_path);
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#ifdef CONFIG_VALIDATE_FS_PARSER
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/**
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* validate_constant_table - Validate a constant table
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* @name: Name to use in reporting
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* @tbl: The constant table to validate.
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* @tbl_size: The size of the table.
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* @low: The lowest permissible value.
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* @high: The highest permissible value.
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* @special: One special permissible value outside of the range.
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*/
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bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size,
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int low, int high, int special)
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{
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size_t i;
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bool good = true;
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if (tbl_size == 0) {
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pr_warn("VALIDATE C-TBL: Empty\n");
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return true;
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}
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for (i = 0; i < tbl_size; i++) {
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if (!tbl[i].name) {
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pr_err("VALIDATE C-TBL[%zu]: Null\n", i);
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good = false;
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} else if (i > 0 && tbl[i - 1].name) {
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int c = strcmp(tbl[i-1].name, tbl[i].name);
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if (c == 0) {
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pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n",
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i, tbl[i].name);
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good = false;
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}
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if (c > 0) {
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pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n",
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i, tbl[i-1].name, tbl[i].name);
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good = false;
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}
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}
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if (tbl[i].value != special &&
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(tbl[i].value < low || tbl[i].value > high)) {
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pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n",
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i, tbl[i].name, tbl[i].value, low, high);
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good = false;
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}
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}
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return good;
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}
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/**
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* fs_validate_description - Validate a parameter description
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* @desc: The parameter description to validate.
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*/
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bool fs_validate_description(const char *name,
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const struct fs_parameter_spec *desc)
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{
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const struct fs_parameter_spec *param, *p2;
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bool good = true;
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for (param = desc; param->name; param++) {
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/* Check for duplicate parameter names */
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for (p2 = desc; p2 < param; p2++) {
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if (strcmp(param->name, p2->name) == 0) {
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if (is_flag(param) != is_flag(p2))
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continue;
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pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n",
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name, param->name);
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good = false;
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}
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}
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}
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return good;
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}
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#endif /* CONFIG_VALIDATE_FS_PARSER */
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