195 lines
5.6 KiB
Diff
195 lines
5.6 KiB
Diff
From 8a6f0cfd96a3a7f0e72079407af4b8ed705c1ed2 Mon Sep 17 00:00:00 2001
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From: Karel Zak <kzak@redhat.com>
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Date: Mon, 30 Oct 2017 15:04:20 +0100
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Subject: [PATCH] Revert "dmesg: fragment concatenation"
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* introduces regressions
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* stupid code; parse_kmsg_record() called more than once for each record
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This reverts commit 22eb2f0190d8a9850da750641439ccd284ac0bfe.
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---
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sys-utils/dmesg.c | 117 ++++--------------------------------------------------
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1 file changed, 7 insertions(+), 110 deletions(-)
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diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
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index b626380f7..6e5911a76 100644
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--- a/sys-utils/dmesg.c
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+++ b/sys-utils/dmesg.c
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@@ -20,7 +20,6 @@
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#include <sys/stat.h>
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#include <unistd.h>
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#include <fcntl.h>
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-#include <poll.h>
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#include "c.h"
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#include "colors.h"
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@@ -179,8 +178,6 @@ struct dmesg_control {
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int kmsg; /* /dev/kmsg file descriptor */
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ssize_t kmsg_first_read;/* initial read() return code */
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char kmsg_buf[BUFSIZ];/* buffer to read kmsg data */
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- char kmsg_saved[BUFSIZ];/* buffer to save line after fragment */
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- ssize_t kmsg_saved_size; /* if nonzero, read from kmsg_saved */
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/*
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* For the --file option we mmap whole file. The unnecessary (already
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@@ -209,7 +206,6 @@ struct dmesg_record {
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int level;
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int facility;
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struct timeval tv;
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- char flags;
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const char *next; /* buffer with next unparsed record */
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size_t next_size; /* size of the next buffer */
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@@ -226,13 +222,6 @@ struct dmesg_record {
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static int read_kmsg(struct dmesg_control *ctl);
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-
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-static int parse_kmsg_record(struct dmesg_control *ctl,
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- struct dmesg_record *rec,
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- char *buf,
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- size_t sz);
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-
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-
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static int set_level_color(int log_level, const char *mesg, size_t mesgsz)
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{
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int id = -1;
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@@ -1024,101 +1013,15 @@ static void print_buffer(struct dmesg_control *ctl,
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print_record(ctl, &rec);
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}
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-/*
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- * Read one record from kmsg, automatically concatenating message fragments
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- */
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static ssize_t read_kmsg_one(struct dmesg_control *ctl)
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{
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ssize_t size;
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- struct dmesg_record rec = { .flags = 0 };
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- char fragment_buf[BUFSIZ] = { 0 };
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- ssize_t fragment_offset = 0;
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-
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- if (ctl->kmsg_saved_size != 0) {
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- size = ctl->kmsg_saved_size;
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- memcpy(ctl->kmsg_buf, ctl->kmsg_saved, size);
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- ctl->kmsg_saved_size = 0;
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- return size;
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- }
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- /*
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- * kmsg returns EPIPE if record was modified while reading.
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- * Read records until there is one with a flag different from 'c'/'+',
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- * which indicates that a fragment (if it exists) is complete.
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- */
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+ /* kmsg returns EPIPE if record was modified while reading */
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do {
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- /*
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- * If there is a fragment in progress, and we're in follow mode,
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- * read with a timeout so that if no line is read in 100ms, we can
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- * assume that the fragment is the last line in /dev/kmsg and it
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- * is completed.
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- */
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- if (ctl->follow && fragment_offset) {
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- struct pollfd pfd = {.fd = ctl->kmsg, .events = POLLIN};
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- poll(&pfd, 1, 100);
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- /* If 100ms has passed and kmsg has no data to read() */
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- if (!(pfd.revents & POLLIN)) {
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- memcpy(ctl->kmsg_buf, fragment_buf, fragment_offset);
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- return fragment_offset + 1;
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- }
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- }
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- size = read(ctl->kmsg, ctl->kmsg_buf, sizeof(ctl->kmsg_buf) - 1);
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-
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- /*
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- * If read() would have blocked and we have a fragment in
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- * progress, assume that it's completed (ie. it was the last line
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- * in the ring buffer) otherwise it won't be displayed until
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- * another non-fragment message is logged.
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- */
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- if (errno == EAGAIN && fragment_offset) {
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- memcpy(ctl->kmsg_buf, fragment_buf, fragment_offset);
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- return fragment_offset + 1;
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- }
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-
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- if (parse_kmsg_record(ctl, &rec, ctl->kmsg_buf,
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- (size_t) size) == 0) {
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- /*
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- * 'c' can indicate a start of a fragment or a
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- * continuation, '+' is used in older kernels to
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- * indicate a continuation.
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- */
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- if (rec.flags == 'c' || rec.flags == '+') {
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- if (!fragment_offset) {
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- memcpy(fragment_buf, ctl->kmsg_buf, size);
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- fragment_offset = size - 1;
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- } else {
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- /*
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- * In case of a buffer overflow, just
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- * truncate the fragment - no one should
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- * be logging this much anyway
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- */
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- ssize_t truncate_size = min(
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- fragment_offset + rec.mesg_size,
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- sizeof(fragment_buf));
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-
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- memcpy(fragment_buf + fragment_offset,
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- rec.mesg, truncate_size);
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- fragment_offset += rec.mesg_size;
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- }
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-
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- } else if (rec.flags == '-') {
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- /*
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- * If there was a fragment being built, move it
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- * into kmsg_buf, but first save a copy of the
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- * current message so that it doesn't get lost.
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- */
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- if (fragment_offset) {
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- memcpy(ctl->kmsg_saved,
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- ctl->kmsg_buf, size);
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- ctl->kmsg_saved_size = size;
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- memcpy(ctl->kmsg_buf,
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- fragment_buf, fragment_offset);
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- return fragment_offset + 1;
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- }
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- }
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- }
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- } while ((size < 0 && errno == EPIPE) ||
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- (rec.flags == 'c' || rec.flags == '+'));
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+ size = read(ctl->kmsg, ctl->kmsg_buf,
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+ sizeof(ctl->kmsg_buf) - 1);
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+ } while (size < 0 && errno == EPIPE);
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return size;
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}
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@@ -1212,17 +1115,11 @@ static int parse_kmsg_record(struct dmesg_control *ctl,
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if (LAST_KMSG_FIELD(p))
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goto mesg;
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- /* D) flags */
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- rec->flags = *p; // flag is one char
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- p = p + 1;
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- if (LAST_KMSG_FIELD(p))
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- goto mesg;
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-
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- /* E) optional fields (ignore) */
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+ /* D) optional fields (ignore) */
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p = skip_item(p, end, ";");
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mesg:
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- /* F) message text */
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+ /* E) message text */
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rec->mesg = p;
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p = skip_item(p, end, "\n");
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@@ -1238,7 +1135,7 @@ mesg:
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*/
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unhexmangle_to_buffer(rec->mesg, (char *) rec->mesg, rec->mesg_size + 1);
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- /* G) message tags (ignore) */
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+ /* F) message tags (ignore) */
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return 0;
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}
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--
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2.13.6
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