Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754169Ab2KCVNc (ORCPT ); Sat, 3 Nov 2012 17:13:32 -0400 Received: from mail.eecsit.tu-berlin.de ([130.149.17.13]:60912 "EHLO mail.cs.tu-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751323Ab2KCVNb (ORCPT ); Sat, 3 Nov 2012 17:13:31 -0400 From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Kay Sievers , =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= Subject: [PATCH resend] printk: drop ambiguous LOG_CONT flag Date: Sat, 3 Nov 2012 22:12:56 +0100 Message-Id: <1351977176-28381-1-git-send-email-schnhrr@cs.tu-berlin.de> X-Mailer: git-send-email 1.8.0.316.g291341c.dirty In-Reply-To: <20121102233610.GA3239@kroah.com> References: <20121102233610.GA3239@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6344 Lines: 187 From: Jan H. Schönherr The meaning of LOG_CONT is unclear, i. e., whether a message is a starting, ending, or middle fragment. Unfortunately, this cannot be inferred from the LOG_PREFIX and LOG_NEWLINE flags, as they are not always kept. Furthermore, in some cases LOG_CONT is set, although it is unknown if there will be a continuation. This leads to wrongly concatenated output. Fix this by dropping LOG_CONT and rely on LOG_PREFIX and LOG_NEWLINE to distinguish the type of fragment. That is, if LOG_PREFIX is set, this fragment does not continue the previous fragment. And if LOG_NEWLINE is set, this fragment is not continued by the next fragment. (Unfortunately, we still have to look at the previous fragment to catch the case of an unset LOG_PREFIX on this fragment, but a set LOG_NEWLINE on the previous fragment.) Tested-By: Kay Sievers Signed-off-by: Jan H. Schönherr --- Against linux-next from 20121102, added Kay's tested-by. --- kernel/printk.c | 57 +++++++++++++++++++++++++++++++++------------------------ 1 file changed, 33 insertions(+), 24 deletions(-) diff --git a/kernel/printk.c b/kernel/printk.c index 22e070f..e8e4e67 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -203,7 +203,6 @@ enum log_flags { LOG_NOCONS = 1, /* already flushed, do not print to console */ LOG_NEWLINE = 2, /* text ended with a newline */ LOG_PREFIX = 4, /* text started with a prefix */ - LOG_CONT = 8, /* text is a fragment of a continuation line */ }; struct log { @@ -487,10 +486,9 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, * better readable output. 'c' in the record flags mark the first * fragment of a line, '+' the following. */ - if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT)) + if (!(msg->flags & LOG_NEWLINE) && msg->flags & LOG_PREFIX) cont = 'c'; - else if ((msg->flags & LOG_CONT) || - ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) + else if (!(user->prev & LOG_NEWLINE) && !(msg->flags & LOG_PREFIX)) cont = '+'; len = sprintf(user->buf, "%u,%llu,%llu,%c;", @@ -893,15 +891,17 @@ static size_t msg_print_text(const struct log *msg, enum log_flags prev, bool newline = true; size_t len = 0; - if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) + if (!(prev & LOG_NEWLINE) && !(msg->flags & LOG_PREFIX)) prefix = false; - if (msg->flags & LOG_CONT) { - if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) - prefix = false; + if (!(msg->flags & LOG_NEWLINE)) + newline = false; - if (!(msg->flags & LOG_NEWLINE)) - newline = false; + if (!(prev & LOG_NEWLINE) && prefix) { + if (buf) + buf[len++] = '\n'; + else + len++; } do { @@ -1406,35 +1406,36 @@ static void cont_flush(enum log_flags flags) if (cont.len == 0) return; + cont.flags |= flags; if (cont.cons) { /* * If a fragment of this line was directly flushed to the * console; wait for the console to pick up the rest of the * line. LOG_NOCONS suppresses a duplicated output. */ - log_store(cont.facility, cont.level, flags | LOG_NOCONS, + log_store(cont.facility, cont.level, cont.flags | LOG_NOCONS, cont.ts_nsec, NULL, 0, cont.buf, cont.len); - cont.flags = flags; cont.flushed = true; } else { /* * If no fragment of this line ever reached the console, * just submit it to the store and free the buffer. */ - log_store(cont.facility, cont.level, flags, 0, + log_store(cont.facility, cont.level, cont.flags, 0, NULL, 0, cont.buf, cont.len); cont.len = 0; } } -static bool cont_add(int facility, int level, const char *text, size_t len) +static bool cont_add(int facility, int level, enum log_flags flags, + const char *text, size_t len) { if (cont.len && cont.flushed) return false; if (cont.len + len > sizeof(cont.buf)) { /* the line gets too long, split it up in separate records */ - cont_flush(LOG_CONT); + cont_flush(0); return false; } @@ -1443,7 +1444,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len) cont.level = level; cont.owner = current; cont.ts_nsec = local_clock(); - cont.flags = 0; + cont.flags = flags; cont.cons = 0; cont.flushed = false; } @@ -1452,7 +1453,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len) cont.len += len; if (cont.len > (sizeof(cont.buf) * 80) / 100) - cont_flush(LOG_CONT); + cont_flush(0); return true; } @@ -1462,8 +1463,11 @@ static size_t cont_print_text(char *text, size_t size) size_t textlen = 0; size_t len; - if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { - textlen += print_time(cont.ts_nsec, text); + if (cont.cons == 0 && (console_prev & LOG_NEWLINE || + cont.flags & LOG_PREFIX)) { + if (!(console_prev & LOG_NEWLINE)) + text[textlen++] = '\n'; + textlen += print_time(cont.ts_nsec, text + textlen); size -= textlen; } @@ -1581,12 +1585,16 @@ asmlinkage int vprintk_emit(int facility, int level, * Flush the conflicting buffer. An earlier newline was missing, * or another task also prints continuation lines. */ - if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) - cont_flush(LOG_NEWLINE); + if (cont.len) { + if (cont.owner != current) + lflags |= LOG_PREFIX; + if (lflags & LOG_PREFIX) + cont_flush(LOG_NEWLINE); + } /* buffer line if possible, otherwise store it right away */ - if (!cont_add(facility, level, text, text_len)) - log_store(facility, level, lflags | LOG_CONT, 0, + if (!cont_add(facility, level, lflags, text, text_len)) + log_store(facility, level, lflags, 0, dict, dictlen, text, text_len); } else { bool stored = false; @@ -1599,7 +1607,8 @@ asmlinkage int vprintk_emit(int facility, int level, */ if (cont.len && cont.owner == current) { if (!(lflags & LOG_PREFIX)) - stored = cont_add(facility, level, text, text_len); + stored = cont_add(facility, level, lflags, + text, text_len); cont_flush(LOG_NEWLINE); } -- 1.8.0.316.g291341c.dirty -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/