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([2a00:1370:818c:4a57:2186:c463:9ced:e6fe]) by smtp.gmail.com with ESMTPSA id c61-20020a509fc3000000b004acbe0b36d2sm1266910edf.6.2023.02.12.03.11.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Feb 2023 03:11:13 -0800 (PST) To: bug-hurd@gnu.org, libc-alpha@sourceware.org Cc: =?utf-8?q?Fl=C3=A1vio_Cruz?= , Sergey Bugaev Subject: [RFC PATCH glibc 1/12] hurd: Refactor readlinkat() Date: Sun, 12 Feb 2023 14:10:32 +0300 Message-Id: <20230212111044.610942-2-bugaevc@gmail.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230212111044.610942-1-bugaevc@gmail.com> References: <20230212111044.610942-1-bugaevc@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-10.4 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Sergey Bugaev via Libc-alpha From: Sergey Bugaev Reply-To: Sergey Bugaev Errors-To: libc-alpha-bounces+incoming=patchwork.ozlabs.org@sourceware.org Sender: "Libc-alpha" Make the code flow more linear using early returns where possible. This makes it so much easier to reason about what runs on error / successful code paths. Signed-off-by: Sergey Bugaev --- sysdeps/mach/hurd/readlinkat.c | 55 ++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 23 deletions(-) diff --git a/sysdeps/mach/hurd/readlinkat.c b/sysdeps/mach/hurd/readlinkat.c index 1efb09ca..dabdbb37 100644 --- a/sysdeps/mach/hurd/readlinkat.c +++ b/sysdeps/mach/hurd/readlinkat.c @@ -31,38 +31,47 @@ __readlinkat (int fd, const char *file_name, char *buf, size_t len) error_t err; file_t file_stat; struct stat64 st; + enum retry_type doretry; + char retryname[1024]; + file_t file; + char *rbuf = buf; file_stat = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0); if (file_stat == MACH_PORT_NULL) return -1; err = __io_stat (file_stat, &st); - if (! err) - if (S_ISLNK (st.st_mode)) - { - enum retry_type doretry; - char retryname[1024]; - file_t file; - char *rbuf = buf; + if (err) + goto out; + if (!S_ISLNK (st.st_mode)) + { + err = EINVAL; + goto out; + } - err = __dir_lookup (file_stat, "", O_READ | O_NOLINK, 0, &doretry, retryname, &file); - if (! err && (doretry != FS_RETRY_NORMAL || retryname[0] != '\0')) - err = EGRATUITOUS; - if (! err) - { - err = __io_read (file, &rbuf, &len, 0, len); - if (!err && rbuf != buf) - { - memcpy (buf, rbuf, len); - __vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len); - } + err = __dir_lookup (file_stat, "", O_READ | O_NOLINK, + 0, &doretry, retryname, &file); + if (err) + goto out; + if (doretry != FS_RETRY_NORMAL || retryname[0] != '\0') + { + err = EGRATUITOUS; + goto out; + } + + err = __io_read (file, &rbuf, &len, 0, len); + __mach_port_deallocate (__mach_task_self (), file); + if (err) + goto out; + + if (rbuf != buf) + { + memcpy (buf, rbuf, len); + __vm_deallocate (__mach_task_self (), (vm_address_t) rbuf, len); + } - __mach_port_deallocate (__mach_task_self (), file); - } - } - else - err = EINVAL; + out: __mach_port_deallocate (__mach_task_self (), file_stat); return err ? __hurd_fail (err) : len;