From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Osmialowski Subject: [RFC v2 6/9] kmsg: add predefined _PID, _TID, _COMM keywords to kmsg* log dict Date: Mon, 12 Oct 2015 11:29:14 +0200 Message-ID: <1444642157-32618-7-git-send-email-p.osmialowsk@samsung.com> References: <1444642157-32618-1-git-send-email-p.osmialowsk@samsung.com> Return-path: In-reply-to: <1444642157-32618-1-git-send-email-p.osmialowsk@samsung.com> Sender: linux-doc-owner@vger.kernel.org To: Jonathan Corbet , Arnd Bergmann , Andrew Morton , Petr Mladek , Greg Kroah-Hartman , Daniel Mack , Kay Sievers , Joe Perches , Tejun Heo , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-api@vger.kernel.org Cc: Marcin Niesluchowski , Karol Lewandowski , Paul Osmialowski , Bartlomiej Zolnierkiewicz , Shuah Khan List-Id: linux-api@vger.kernel.org From: Marcin Niesluchowski kmsg* devices write operation wrote no dict along with message Due to usage of kmsg devices in userspace dict has been added identifying pid, tid and comm of writing process. Signed-off-by: Marcin Niesluchowski --- kernel/printk/printk.c | 40 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 36 insertions(+), 4 deletions(-) diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index aac7ce8..c13ba89 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -877,7 +877,34 @@ void log_buf_release(struct kref *ref) kfree(log_b); } -static int kmsg_sys_write(int minor, int level, const char *fmt, ...) +#define MAX_PID_LEN 20 +#define MAX_TID_LEN 20 +/* + * Fromat below describes dict appended to message written from userspace: + * "_PID=\0_TID=\0_COMM=" + * KMSG_DICT_MAX_LEN definition represents maximal length of this dict. + */ +#define KMSG_DICT_MAX_LEN (5 + MAX_PID_LEN + 1 + \ + 5 + MAX_TID_LEN + 1 + \ + 6 + TASK_COMM_LEN) + +static size_t set_kmsg_dict(char *buf) +{ + size_t len; + + len = sprintf(buf, "_PID=%d", task_tgid_nr(current)) + 1; + len += sprintf(buf + len, "_TID=%d", task_pid_nr(current)) + 1; + memcpy(buf + len, "_COMM=", 6); + len += 6; + get_task_comm(buf + len, current); + while (buf[len] != '\0') + len++; + return len; +} + +static int kmsg_sys_write(int minor, int level, + const char *dict, size_t dictlen, + const char *fmt, ...) { va_list args; int ret = -ENXIO; @@ -892,7 +919,7 @@ static int kmsg_sys_write(int minor, int level, const char *fmt, ...) va_start(args, fmt); log_format_and_store(log_b, 1 /* LOG_USER */, level, - NULL, 0, fmt, args); + dict, dictlen, fmt, args); va_end(args); wake_up_interruptible(&log_b->wait); @@ -912,6 +939,8 @@ static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) int level = default_message_loglevel; int facility = 1; /* LOG_USER */ size_t len = iov_iter_count(from); + char dict[KMSG_DICT_MAX_LEN]; + size_t dictlen; ssize_t ret = len; int minor = iminor(iocb->ki_filp->f_inode); @@ -951,10 +980,13 @@ static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from) } } + dictlen = set_kmsg_dict(dict); + if (minor == log_buf.minor) { - printk_emit(facility, level, NULL, 0, "%s", line); + printk_emit(facility, level, dict, dictlen, "%s", line); } else { - int error = kmsg_sys_write(minor, level, "%s", line); + int error = kmsg_sys_write(minor, level, dict, dictlen, + "%s", line); if (error) ret = error; -- 1.9.1