Revert "dmesg: fragment concatenation"

* introduces regressions
* stupid code; parse_kmsg_record() called more than once for each record

This reverts commit 22eb2f0190d8a9850da750641439ccd284ac0bfe.

diff --git a/sys-utils/dmesg.c b/sys-utils/dmesg.c
index b626380f7e96c57522df2bfa1da63c6c58656c69..6e5911a76dc891221b2e8612562f605caf424a09 100644 (file)
--- a/sys-utils/dmesg.c
+++ b/sys-utils/dmesg.c
@@ -20,7 +20,6 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <fcntl.h>
-#include <poll.h>
 
 #include "c.h"
 #include "colors.h"
@@ -179,8 +178,6 @@ struct dmesg_control {
        int             kmsg;           /* /dev/kmsg file descriptor */
        ssize_t         kmsg_first_read;/* initial read() return code */
        char            kmsg_buf[BUFSIZ];/* buffer to read kmsg data */
-       char            kmsg_saved[BUFSIZ];/* buffer to save line after fragment */
-       ssize_t         kmsg_saved_size;  /* if nonzero, read from kmsg_saved */
 
        /*
         * For the --file option we mmap whole file. The unnecessary (already
@@ -209,7 +206,6 @@ struct dmesg_record {
        int             level;
        int             facility;
        struct timeval  tv;
-       char            flags;
 
        const char      *next;          /* buffer with next unparsed record */
        size_t          next_size;      /* size of the next buffer */
@@ -226,13 +222,6 @@ struct dmesg_record {
 
 static int read_kmsg(struct dmesg_control *ctl);
 
-
-static int parse_kmsg_record(struct dmesg_control *ctl,
-                            struct dmesg_record *rec,
-                            char *buf,
-                            size_t sz);
-
-
 static int set_level_color(int log_level, const char *mesg, size_t mesgsz)
 {
        int id = -1;
@@ -1024,101 +1013,15 @@ static void print_buffer(struct dmesg_control *ctl,
                print_record(ctl, &rec);
 }
 
-/*
- * Read one record from kmsg, automatically concatenating message fragments
- */
 static ssize_t read_kmsg_one(struct dmesg_control *ctl)
 {
        ssize_t size;
-       struct dmesg_record rec = { .flags = 0 };
-       char fragment_buf[BUFSIZ] = { 0 };
-       ssize_t fragment_offset = 0;
-
-       if (ctl->kmsg_saved_size != 0) {
-               size = ctl->kmsg_saved_size;
-               memcpy(ctl->kmsg_buf, ctl->kmsg_saved, size);
-               ctl->kmsg_saved_size = 0;
-               return size;
-       }
 
-       /*
-        * kmsg returns EPIPE if record was modified while reading.
-        * Read records until there is one with a flag different from 'c'/'+',
-        * which indicates that a fragment (if it exists) is complete.
-        */
+       /* kmsg returns EPIPE if record was modified while reading */
        do {
-               /*
-                * If there is a fragment in progress, and we're in follow mode,
-                * read with a timeout so that if no line is read in 100ms, we can
-                * assume that the fragment is the last line in /dev/kmsg and it
-                * is completed.
-                */
-               if (ctl->follow && fragment_offset) {
-                       struct pollfd pfd = {.fd = ctl->kmsg, .events = POLLIN};
-                       poll(&pfd, 1, 100);
-                       /* If 100ms has passed and kmsg has no data to read() */
-                       if (!(pfd.revents & POLLIN)) {
-                               memcpy(ctl->kmsg_buf, fragment_buf, fragment_offset);
-                               return fragment_offset + 1;
-                       }
-               }
-               size = read(ctl->kmsg, ctl->kmsg_buf, sizeof(ctl->kmsg_buf) - 1);
-
-               /*
-                * If read() would have blocked and we have a fragment in
-                * progress, assume that it's completed (ie. it was the last line
-                * in the ring buffer) otherwise it won't be displayed until
-                * another non-fragment message is logged.
-                */
-               if (errno == EAGAIN && fragment_offset) {
-                       memcpy(ctl->kmsg_buf, fragment_buf, fragment_offset);
-                       return fragment_offset + 1;
-               }
-
-               if (parse_kmsg_record(ctl, &rec, ctl->kmsg_buf,
-                                    (size_t) size) == 0) {
-                       /*
-                        * 'c' can indicate a start of a fragment or a
-                        * continuation, '+' is used in older kernels to
-                        * indicate a continuation.
-                        */
-                       if (rec.flags == 'c' || rec.flags == '+') {
-                               if (!fragment_offset) {
-                                       memcpy(fragment_buf, ctl->kmsg_buf, size);
-                                       fragment_offset = size - 1;
-                               } else {
-                                       /*
-                                        * In case of a buffer overflow, just
-                                        * truncate the fragment - no one should
-                                        * be logging this much anyway
-                                        */
-                                       ssize_t truncate_size = min(
-                                                   fragment_offset + rec.mesg_size,
-                                                   sizeof(fragment_buf));
-
-                                       memcpy(fragment_buf + fragment_offset,
-                                              rec.mesg, truncate_size);
-                                       fragment_offset += rec.mesg_size;
-                               }
-
-                       } else if (rec.flags == '-') {
-                               /*
-                                * If there was a fragment being built, move it
-                                * into kmsg_buf, but first save a copy of the
-                                * current message so that it doesn't get lost.
-                                */
-                               if (fragment_offset) {
-                                       memcpy(ctl->kmsg_saved,
-                                              ctl->kmsg_buf, size);
-                                       ctl->kmsg_saved_size = size;
-                                       memcpy(ctl->kmsg_buf,
-                                              fragment_buf, fragment_offset);
-                                       return fragment_offset + 1;
-                               }
-                       }
-               }
-       } while ((size < 0 && errno == EPIPE) ||
-                (rec.flags == 'c' || rec.flags == '+'));
+               size = read(ctl->kmsg, ctl->kmsg_buf,
+                           sizeof(ctl->kmsg_buf) - 1);
+       } while (size < 0 && errno == EPIPE);
 
        return size;
 }
@@ -1212,17 +1115,11 @@ static int parse_kmsg_record(struct dmesg_control *ctl,
        if (LAST_KMSG_FIELD(p))
                goto mesg;
 
-       /* D) flags */
-       rec->flags = *p; // flag is one char
-       p = p + 1;
-       if (LAST_KMSG_FIELD(p))
-               goto mesg;
-
-       /* E) optional fields (ignore) */
+       /* D) optional fields (ignore) */
        p = skip_item(p, end, ";");
 
 mesg:
-       /* F) message text */
+       /* E) message text */
        rec->mesg = p;
        p = skip_item(p, end, "\n");
 
@@ -1238,7 +1135,7 @@ mesg:
         */
        unhexmangle_to_buffer(rec->mesg, (char *) rec->mesg, rec->mesg_size + 1);
 
-       /* G) message tags (ignore) */
+       /* F) message tags (ignore) */
 
        return 0;
 }