From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8E270C433EF for ; Sat, 26 Mar 2022 14:18:29 +0000 (UTC) Received: from localhost ([::1]:60016 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nY7FM-000743-Mq for qemu-devel@archiver.kernel.org; Sat, 26 Mar 2022 10:18:28 -0400 Received: from eggs.gnu.org ([209.51.188.92]:34912) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nY6UI-00030M-DE for qemu-devel@nongnu.org; Sat, 26 Mar 2022 09:29:51 -0400 Received: from [2001:4860:4864:20::2d] (port=32816 helo=mail-oa1-x2d.google.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nY6UF-0005zb-Vy for qemu-devel@nongnu.org; Sat, 26 Mar 2022 09:29:49 -0400 Received: by mail-oa1-x2d.google.com with SMTP id 586e51a60fabf-de3eda6b5dso10779801fac.0 for ; Sat, 26 Mar 2022 06:29:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=kcCuxlkVT075lpymlA6JruiT9pScLcSGcIoU5KgWuJw=; b=u4ZSZkxsqAG1mYUX8YiHStfuMI9U7Bs+FMvrw/WlD5GAzWOp+5Q05v426CuKBZcyfJ uFl546MqcuAzz+eezB/HN5Y5Qfh0xGJUIdIYE/TGgcam8ncXXTGHeGlZO7sRShw9XZSR pBD43dnXthI9QrdRhz9fjeBPTFB9jTr18j7X2aaKC+5h2WRZ1Ca/LveXukY2liQ/aWQj dWdNtix2Dme7B/8Ld8jCPvcJEMuKNQ1v8Hb3vtkxUGdNjt257YBelC4yMt0tdOZJBzk0 lPwnN6S+nclZVNemy2nTSQcGniG6DA6EgvWpq+Dk5fhjeGOrpBENv1Gra7ewHXzzZvQE v8YA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=kcCuxlkVT075lpymlA6JruiT9pScLcSGcIoU5KgWuJw=; b=CkS3n6A4+2tuNtCoZAg3urOqsjeCmHsQbxTD2GGXfwGsi7Rm4o2ULIVtgDpg6W5aU8 HU6vW0PNuKIo+Ugj8Wejmi2HiqeZy6/Sx5giQkzt07wb03HPP0d/iXwfzYvhx023wvUP 1AvuNIt/97Px4MjxvPGCxjpH/lkGw9G1Dg9cTWTO0F+H29K+pZzHfPUm7wCS7kp6d0SJ yjFaTGgbRGBPwt9K325OI9SAD9BYjfbMtpK5vQrfi+7VKoCDxk7n+Mub6mSEeH1tRFyg SnTxAZOrk42zrSolod7YZwuliFomWJ+Wd5oOIvtVNu1ww1XAtYjfTvnH46/DL4dsRSI7 nUAw== X-Gm-Message-State: AOAM532KIk3Kz4RUeThFP0XXIsDLsRLDNoApKMKQ7aaCEvX3M5F2GpEI mQcy2NQ4ahnqTQDjsJ0dX91CGVAx8/ZO4j7/ X-Google-Smtp-Source: ABdhPJxNKOvJihQWBa7yc33j0u+TShzDrDgmjKnmNxPhWzJbiW/rQDsd+3obVTGjAMKSoCkbIKixUg== X-Received: by 2002:a05:6870:6108:b0:dd:ca26:f135 with SMTP id s8-20020a056870610800b000ddca26f135mr6978707oae.22.1648301386934; Sat, 26 Mar 2022 06:29:46 -0700 (PDT) Received: from localhost.localdomain (168.189-204-159.bestelclientes.com.mx. [189.204.159.168]) by smtp.gmail.com with ESMTPSA id s24-20020a056808209800b002da3b9bf8e0sm4394509oiw.32.2022.03.26.06.29.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Mar 2022 06:29:46 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Subject: [PATCH v2 39/39] util/log: Support per-thread log files Date: Sat, 26 Mar 2022 07:25:34 -0600 Message-Id: <20220326132534.543738-48-richard.henderson@linaro.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220326132534.543738-1-richard.henderson@linaro.org> References: <20220326132534.543738-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Host-Lookup-Failed: Reverse DNS lookup failed for 2001:4860:4864:20::2d (failed) Received-SPF: pass client-ip=2001:4860:4864:20::2d; envelope-from=richard.henderson@linaro.org; helo=mail-oa1-x2d.google.com X-Spam_score_int: -6 X-Spam_score: -0.7 X-Spam_bar: / X-Spam_report: (-0.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, PDS_HP_HELO_NORDNS=0.659, RDNS_NONE=0.793, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alex.bennee@linaro.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add a new log flag, tid, to turn this feature on. Require the log filename to be set, and to contain %d. Do not allow tid to be turned off once it is on, nor let the filename be change thereafter. This avoids the need for signalling each thread to re-open on a name change. Signed-off-by: Richard Henderson --- v2: Make use of CONFIG_GETTID, and fallback to SYS_gettid. --- include/qemu/log.h | 1 + util/log.c | 149 ++++++++++++++++++++++++++++++++++----------- 2 files changed, 115 insertions(+), 35 deletions(-) diff --git a/include/qemu/log.h b/include/qemu/log.h index a325bca661..c5643d8dd5 100644 --- a/include/qemu/log.h +++ b/include/qemu/log.h @@ -34,6 +34,7 @@ bool qemu_log_separate(void); #define CPU_LOG_PLUGIN (1 << 18) /* LOG_STRACE is used for user-mode strace logging. */ #define LOG_STRACE (1 << 19) +#define LOG_PER_THREAD (1 << 20) /* Lock/unlock output. */ diff --git a/util/log.c b/util/log.c index df0710720f..0bb2233788 100644 --- a/util/log.c +++ b/util/log.c @@ -27,6 +27,9 @@ #include "qemu/thread.h" #include "qemu/lockable.h" #include "qemu/rcu.h" +#ifdef CONFIG_LINUX +#include +#endif typedef struct RCUCloseFILE { @@ -38,22 +41,36 @@ typedef struct RCUCloseFILE { static QemuMutex global_mutex; static char *global_filename; static FILE *global_file; +static __thread FILE *thread_file; int qemu_loglevel; -static int log_append = 0; +static bool log_append; +static bool log_per_thread; static GArray *debug_regions; /* Returns true if qemu_log() will really write somewhere. */ bool qemu_log_enabled(void) { - return qatomic_read(&global_file) != NULL; + return log_per_thread || qatomic_read(&global_file) != NULL; } /* Returns true if qemu_log() will write somewhere other than stderr. */ bool qemu_log_separate(void) { FILE *logfile = qatomic_read(&global_file); - return logfile && logfile != stderr; + return log_per_thread || (logfile && logfile != stderr); +} + +static int log_thread_id(void) +{ +#ifdef CONFIG_GETTID + return gettid(); +#elif defined(SYS_gettid) + return syscall(SYS_gettid); +#else + static int counter; + return qatomic_fetch_inc(&counter); +#endif } /* Lock/unlock output. */ @@ -62,20 +79,34 @@ FILE *qemu_log_trylock(void) { FILE *logfile; - rcu_read_lock(); - /* - * FIXME: typeof_strip_qual, as used by qatomic_rcu_read, - * does not work with pointers to undefined structures, - * such as we have with struct _IO_FILE and musl libc. - * Since all we want is a read of a pointer, cast to void**, - * which does work with typeof_strip_qual. - */ - logfile = qatomic_rcu_read((void **)&global_file); - if (logfile) { - qemu_flockfile(logfile); - } else { - rcu_read_unlock(); + logfile = thread_file; + if (!logfile) { + if (log_per_thread) { + g_autofree char *filename + = g_strdup_printf(global_filename, log_thread_id()); + logfile = fopen(filename, "w"); + if (!logfile) { + return NULL; + } + thread_file = logfile; + } else { + rcu_read_lock(); + /* + * FIXME: typeof_strip_qual, as used by qatomic_rcu_read, + * does not work with pointers to undefined structures, + * such as we have with struct _IO_FILE and musl libc. + * Since all we want is a read of a pointer, cast to void**, + * which does work with typeof_strip_qual. + */ + logfile = qatomic_rcu_read((void **)&global_file); + if (!logfile) { + rcu_read_unlock(); + return NULL; + } + } } + + qemu_flockfile(logfile); return logfile; } @@ -84,7 +115,9 @@ void qemu_log_unlock(FILE *logfile) if (logfile) { fflush(logfile); qemu_funlockfile(logfile); - rcu_read_unlock(); + if (!log_per_thread) { + rcu_read_unlock(); + } } } @@ -112,40 +145,74 @@ static void rcu_close_file(RCUCloseFILE *r) g_free(r); } +/** + * valid_filename_template: + * + * Validate the filename template. Require %d if per_thread, allow it + * otherwise; require no other % within the template. + * Return 0 if invalid, 1 if stderr, 2 if strdup, 3 if pid printf. + */ +static int valid_filename_template(const char *filename, + bool per_thread, Error **errp) +{ + if (filename) { + char *pidstr = strstr(filename, "%"); + + if (pidstr) { + /* We only accept one %d, no other format strings */ + if (pidstr[1] != 'd' || strchr(pidstr + 2, '%')) { + error_setg(errp, "Bad logfile template: %s", filename); + return 0; + } + return per_thread ? 2 : 3; + } + } + if (per_thread) { + error_setg(errp, "Filename template with '%%d' required for 'tid'"); + return 0; + } + return filename ? 2 : 1; +} + /* enable or disable low levels log */ static bool qemu_set_log_internal(const char *filename, bool changed_name, int log_flags, Error **errp) { bool need_to_open_file; bool daemonized; + bool per_thread; FILE *logfile; QEMU_LOCK_GUARD(&global_mutex); logfile = global_file; + per_thread = log_flags & LOG_PER_THREAD; + if (changed_name) { char *newname = NULL; /* - * Allow the user to include %d in their logfile which will be - * substituted with the current PID. This is useful for debugging many - * nested linux-user tasks but will result in lots of logs. - * - * filename may be NULL. In that case, log output is sent to stderr + * Once threads start opening their own log files, we have no + * easy mechanism to tell them all to close and re-open. + * There seems little cause to do so either -- this option + * will most often be used at user-only startup. */ - if (filename) { - char *pidstr = strstr(filename, "%"); + if (log_per_thread) { + error_setg(errp, "Cannot change log filename after setting 'tid'"); + return false; + } - if (pidstr) { - /* We only accept one %d, no other format strings */ - if (pidstr[1] != 'd' || strchr(pidstr + 2, '%')) { - error_setg(errp, "Bad logfile format: %s", filename); - return false; - } - newname = g_strdup_printf(filename, getpid()); - } else { - newname = g_strdup(filename); - } + switch (valid_filename_template(filename, per_thread, errp)) { + case 0: + return false; /* error */ + case 1: + break; /* stderr */ + case 2: + newname = g_strdup(filename); + break; + case 3: + newname = g_strdup_printf(filename, getpid()); + break; } g_free(global_filename); @@ -153,8 +220,17 @@ static bool qemu_set_log_internal(const char *filename, bool changed_name, filename = newname; } else { filename = global_filename; + if (per_thread && !valid_filename_template(filename, true, errp)) { + return false; /* error */ + } } + /* Once the per-thread flag is set, it cannot be unset. */ + if (per_thread) { + log_per_thread = true; + } + /* The flag itself is not relevant for need_to_open_file. */ + log_flags &= ~LOG_PER_THREAD; #ifdef CONFIG_TRACE_LOG log_flags |= LOG_TRACE; #endif @@ -163,12 +239,13 @@ static bool qemu_set_log_internal(const char *filename, bool changed_name, /* * In all cases we only log if qemu_loglevel is set. * Also: + * If per-thread, open the file for each thread in qemu_log_lock. * If not daemonized we will always log either to stderr * or to a file (if there is a filename). * If we are daemonized, we will only log if there is a filename. */ daemonized = is_daemonized(); - need_to_open_file = log_flags && (!daemonized || filename); + need_to_open_file = log_flags && !per_thread && (!daemonized || filename); if (logfile && (!need_to_open_file || changed_name)) { qatomic_rcu_set(&global_file, NULL); @@ -354,6 +431,8 @@ const QEMULogItem qemu_log_items[] = { #endif { LOG_STRACE, "strace", "log every user-mode syscall, its input, and its result" }, + { LOG_PER_THREAD, "tid", + "open a separate log file per thread; filename must contain '%d'" }, { 0, NULL, NULL }, }; -- 2.25.1