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[2620:137:e000::1:20]) by mx.google.com with ESMTP id t127-20020a625f85000000b006434a04f2fdsi1029800pfb.364.2023.05.03.07.19.55; Wed, 03 May 2023 07:20:10 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=i6wbV3qz; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229701AbjECOK7 (ORCPT + 99 others); Wed, 3 May 2023 10:10:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37154 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229830AbjECOK4 (ORCPT ); Wed, 3 May 2023 10:10:56 -0400 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D77359F7 for ; Wed, 3 May 2023 07:10:54 -0700 (PDT) Received: by mail-ed1-x54a.google.com with SMTP id 4fb4d7f45d1cf-50bcbb5724aso2831634a12.1 for ; Wed, 03 May 2023 07:10:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1683123053; x=1685715053; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=PscYnQxei+RrA3NkIhxRI+jonTcqCawkESGLIumeLz8=; b=i6wbV3qzZv6N/1ImH/nzBnfPh7xlGmGxBUX8RJPeTpz3tkVH4mRLomkibMuRQlKsUu Mqee2m33k6mtzRHeQ2Vuw4bVPr03n/SZALHA+gNsfJNF+zqbWVnKSFnV0QNCBXO/WyRj 71xunrtFeEha39pnex5dhZSGZySmNlv4pz/07QSarAu+3Sa/HY+MzLbu/QtHAsBziPJI bd+P3Lh8NFBr/9hxE+DXRJt0Uc528bq198eDXLISEIAdqdgIhH6TCEqOM2TPfXsWh3nH REsCRFj2VCIum6c5B2luTkXrsQ40hKLLav9bfRMsgA1At64d1Fd+9EbzeLqpoiz7FPm2 igwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683123053; x=1685715053; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=PscYnQxei+RrA3NkIhxRI+jonTcqCawkESGLIumeLz8=; b=gxlDydSjhD0AkMtAlCMDmrfv6QwG1EQLT1mVyIbJiRkMaJbe9CSKfIHkG4jNIbgtt1 QAl3XRvFKnPWV/WccrYPwfAelnJkTlSyerLYlSEFSbe0O8JZJ0z/n8HdkpDKvgJ3fME9 K35yz1ON8Gcz2CUvoksU+WUpByGrTpKAg7VrvkfQc1+lKWxE2uz0DCOOxByT1NTf0CUk RY8ymtVRKZVTM8Nml3jGUvNzcyjy35o90PjF0PBee4MQhk0X4BIGtz7txVbGaRzjRHyx 8BuSHZrlR1ZKdLuJ34BZW3/ydNllWJGhXTQGPD1TwpOz4Zd/MjNwNwCLUYc+x+tRdhmu Z9Dg== X-Gm-Message-State: AC+VfDynBE817ikHKKpjIlgciLMbOls/TNU1NtZdXcaZ94ib48SAq2u/ Wg8gAVg/set8eg5NJkrX97uKcxGXIce4n2M= X-Received: from aliceryhl.c.googlers.com ([fda3:e722:ac3:cc00:31:98fb:c0a8:6c8]) (user=aliceryhl job=sendgmr) by 2002:a50:d482:0:b0:50b:d28d:a95c with SMTP id s2-20020a50d482000000b0050bd28da95cmr2144272edi.4.1683123052719; Wed, 03 May 2023 07:10:52 -0700 (PDT) Date: Wed, 3 May 2023 14:10:16 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.40.1.495.gc816e09b53d-goog Message-ID: <20230503141016.683634-1-aliceryhl@google.com> Subject: [PATCH v2] rust: str: add conversion from `CStr` to `CString` From: Alice Ryhl To: Miguel Ojeda , Wedson Almeida Filho , Alex Gaynor Cc: Boqun Feng , Gary Guo , " =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= " , Benno Lossin , Martin Rodriguez Reboredo , Alice Ryhl , rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1764883023043185747?= X-GMAIL-MSGID: =?utf-8?q?1764883023043185747?= These methods can be used to copy the data in a temporary c string into a separate allocation, so that it can be accessed later even if the original is deallocated. The API in this change mirrors the standard library API for the `&str` and `String` types. The `ToOwned` trait is not implemented because it assumes that allocations are infallible. Reviewed-by: Benno Lossin Signed-off-by: Alice Ryhl Reviewed-by: Martin Rodriguez Reboredo Reviewed-by: Andreas Hindborg --- rust/kernel/str.rs | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) base-commit: ea76e08f4d901a450619831a255e9e0a4c0ed162 diff --git a/rust/kernel/str.rs b/rust/kernel/str.rs index b771310fa4a4..f3dc5b24ea55 100644 --- a/rust/kernel/str.rs +++ b/rust/kernel/str.rs @@ -2,6 +2,7 @@ //! String representations. +use alloc::alloc::AllocError; use alloc::vec::Vec; use core::fmt::{self, Write}; use core::ops::{self, Deref, Index}; @@ -199,6 +200,12 @@ impl CStr { pub unsafe fn as_str_unchecked(&self) -> &str { unsafe { core::str::from_utf8_unchecked(self.as_bytes()) } } + + /// Convert this [`CStr`] into a [`CString`] by allocating memory and + /// copying over the string data. + pub fn to_cstring(&self) -> Result { + CString::try_from(self) + } } impl fmt::Display for CStr { @@ -584,6 +591,21 @@ impl Deref for CString { } } +impl<'a> TryFrom<&'a CStr> for CString { + type Error = AllocError; + + fn try_from(cstr: &'a CStr) -> Result { + let mut buf = Vec::new(); + + buf.try_extend_from_slice(cstr.as_bytes_with_nul()) + .map_err(|_| AllocError)?; + + // INVARIANT: The `CStr` and `CString` types have the same invariants for + // the string data, and we copied it over without changes. + Ok(CString { buf }) + } +} + /// A convenience alias for [`core::format_args`]. #[macro_export] macro_rules! fmt {