Re: [bug-inetutils] patch circular log feature for syslogd

[Daniel Lehne]

Hello,

so i added this copyright for this patch in the head of the file syslogd.c :
/*
 * Extended for circular log feature:
 * Copyright (c) 2012, AMK Drives & Controls Ltd.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 * MA 02111-1307 USA
 *
 */

Here the patch: 0001-added-circular-log-feature.patch
------------------------------------------------------------------------------------------------------------
From 2fa0ddbe8246f9b678c2395e03e89c1c1659c10d Mon Sep 17 00:00:00 2001
From: Daniel Lehne <address@hidden>
Date: Fri, 23 Nov 2012 15:15:31 +0200
Subject: added circular log feature

---
 src/syslogd.c |  148 
+++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 143 insertions(+), 5 deletions(-)

diff --git a/src/syslogd.c b/src/syslogd.c
index 4fa459a..3869739 100644
--- a/src/syslogd.c
+++ b/src/syslogd.c
@@ -19,6 +19,27 @@
   along with this program.  If not, see `http://www.gnu.org/licenses/'. */

 /*
+ * Extended for circular log feature:
+ * Copyright (c) 2012, AMK Drives & Controls Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
+/*
  * Copyright (c) 1983, 1988, 1993, 1994
  *    The Regents of the University of California.  All rights reserved.
  *
@@ -133,6 +154,7 @@
  * not logged to a file.
  */
 int facilities_seen;
+const char clog_wrap[] = "\n\n";        /* empty line, indicates wrap 
of ringbuffer */

 const char *ConfFile = PATH_LOGCONF;    /* Default Configuration file.  */
 const char *PidFile = PATH_LOGPID;    /* Default path to tuck pid.  */
@@ -182,6 +204,12 @@ struct filed
       struct sockaddr_storage f_addr;
       socklen_t f_addrlen;
     } f_forw;            /* Forwarding address.  */
+    struct {
+      char *f_fname;
+      long int  cf_offset;
+      long int  cf_next;
+      long int  cf_max;
+    } f_clog;                   /* circular log file */
     char *f_fname;        /* Name use for Files|Pipes|TTYs.  */
   } f_un;
   char f_prevline[MAXSVLINE];    /* Last message logged.  */
@@ -208,6 +236,7 @@ struct filed consfile;        /* Console `file'.  */
 #define F_FORW_SUSP    7    /* Suspended host forwarding.  */
 #define F_FORW_UNKN    8    /* Unknown host forwarding.  */
 #define F_PIPE        9    /* Named pipe.  */
+#define F_CLOG          10      /* Circular log) */

 const char *TypeNames[] = {
   "UNUSED",
@@ -219,7 +248,8 @@ const char *TypeNames[] = {
   "WALL",
   "FORW(SUSPENDED)",
   "FORW(UNKNOWN)",
-  "PIPE"
+  "PIPE",
+  "CLOG"
 };

 /* Flags in filed.f_flags.  */
@@ -244,6 +274,10 @@ int repeatinterval[] = { 30, 60 };    /* Number of 
seconds before flush.  */
 /* Delimiter in arguments to command line options `-s' and `-l'. */
 #define LIST_DELIMITER    ':'

+/* Constants for the F_CLOG footer and wrap */
+#define WRAP_CHARS_SIZE sizeof(clog_wrap) /* size of space print on 
wraping the log */
+#define IOV_OFFSET      2                 /* ignore n first elements of 
iov - DATE, SPACE */
+
 extern int waitdaemon (int nochdir, int noclose, int maxwait);

 void cfline (const char *, struct filed *);
@@ -269,6 +303,7 @@ void trigger_restart (int);
 static void add_funix (const char *path);
 static int create_unix_socket (const char *path);
 static void create_inet_socket (int af, int fd46[2]);
+ssize_t clogwritev (struct filed *, struct iovec *, int);

 char *LocalHostName;        /* Our hostname.  */
 char *LocalDomain;        /* Our local domain name.  */
@@ -573,7 +608,8 @@ main (int argc, char *argv[])
   /* Initialize kernel logging and add to the list.  */
   if (!NoKLog)
     {
-      fklog = open (PATH_KLOG, O_RDONLY, 0);
+      /* klog could block system startup, so O_NONBLOCK */
+      fklog = open (PATH_KLOG, O_RDONLY | O_NONBLOCK, 0);
       if (fklog >= 0)
     {
       fdarray[nfds].fd = fklog;
@@ -679,6 +715,7 @@ main (int argc, char *argv[])
       /*dbg_printf ("got a message (%d)\n", nready); */

       for (i = 0; i < nfds; i++)
+      {
     if (fdarray[i].revents & (POLLIN | POLLPRI))
       {
         int result;
@@ -694,10 +731,18 @@ main (int argc, char *argv[])
           {
             kline_len += result;
           }
-        else if (result < 0 && errno != EINTR)
+                  else
           {
-            logerror ("klog");
-            fdarray[i].fd = fklog = -1;
+                    /* catch and tollerate */
+                    if (errno == EAGAIN){
+                      logerror ("klog EAGAIN");
+                    } else if (errno == EINTR){
+                      logerror ("klog EINTR");
+                    } else {
+                     /* stop klog */
+                     logerror ("klog");
+                     fdarray[i].fd = fklog = -1;
+                    }
           }

         while (1)
@@ -805,6 +850,7 @@ main (int argc, char *argv[])
       logerror ("poll err\n");
     else if (fdarray[i].revents & POLLHUP)
       logerror ("poll hup\n");
+      }                         /* for (nfds) */
     }                /* for (;;) */
 }                /* main */

@@ -1497,6 +1543,23 @@ fprintlog (struct filed *f, const char *from, int 
flags, const char *msg)
     fsync (f->f_file);
       break;

+    case F_CLOG:
+      f->f_time = now;
+      dbg_printf(" %s\n", f->f_un.f_fname);
+      v->iov_base = "\n";
+      v->iov_len = 1;
+      if (clogwritev(f, iov, IOVCNT) < 0) {
+        /* failure, disable clog */
+        int e = errno;
+        close(f->f_file);
+        f->f_type = F_UNUSED;
+        errno = e;
+        logerror(f->f_un.f_fname);
+        free(f->f_un.f_fname);
+        f->f_un.f_fname = NULL;
+      }
+      break;
+
     case F_USERS:
     case F_WALL:
       f->f_time = now;
@@ -1771,6 +1834,7 @@ init (int signo _GL_UNUSED_PARAMETER)
     case F_TTY:
     case F_CONSOLE:
     case F_PIPE:
+        case F_CLOG:
       free (f->f_un.f_fname);
       close (f->f_file);
       break;
@@ -1924,6 +1988,7 @@ init (int signo _GL_UNUSED_PARAMETER)
         case F_TTY:
         case F_CONSOLE:
         case F_PIPE:
+            case F_CLOG:
           dbg_printf ("%s", f->f_un.f_fname);
           break;

@@ -2185,6 +2250,45 @@ cfline (const char *line, struct filed *f)
     f->f_type = F_FILE;
       break;

+    /* circular log file */
+    case '%':
+      f->f_type = F_UNUSED;
+      memset(&f->f_un.f_clog, 0, sizeof(f->f_un.f_clog));
+      f->f_un.f_clog.f_fname = strdup(p+1);
+      errno = 0;
+      q = strtok(f->f_un.f_clog.f_fname, " ");
+      if ((errno) || ((f->f_file = open(q, O_WRONLY | O_TRUNC | 
O_CREAT, 0644)) < 0))
+      {
+        free(f->f_un.f_fname);
+        logerror(p);
+        break;
+      }
+      /* parse size */
+      errno = 0;
+      q = strtok(NULL, " ");
+      f->f_un.f_clog.cf_max = strtol(q, NULL ,10);
+      if(errno) {
+        close(f->f_file);
+        free(f->f_un.f_fname);
+        logerror(p);
+        break;
+      }
+      /* parse offset */
+      q = strtok(NULL, " ");
+      errno = 0;
+      f->f_un.f_clog.cf_offset = strtol(q, NULL ,10);
+      if(errno) {
+        close(f->f_file);
+        free(f->f_un.f_fname);
+        logerror(p);
+        break;
+      }
+      /* prohibit invalid offsets */
+      if (f->f_un.f_clog.cf_offset > (f->f_un.f_clog.cf_max - 
WRAP_CHARS_SIZE) )
+        f->f_un.f_clog.cf_offset = 0;
+      f->f_type = F_CLOG;
+      break;
+
     case '*':
       f->f_type = F_WALL;
       break;
@@ -2215,6 +2319,40 @@ cfline (const char *line, struct filed *f)
     }
 }

+/* The following function handles the circular log file access */
+ssize_t clogwritev(struct filed *f, struct iovec *iov, int iovcnt) {
+  int i;
+  ssize_t  out = 0;
+  ssize_t  err = 0;
+  long int diff = 0;
+
+  /* wrap file when data not fit maximum size */
+  for(i=IOV_OFFSET; i<iovcnt; i++)
+    out += iov[i].iov_len;
+  diff = (f->f_un.f_clog.cf_max - f->f_un.f_clog.cf_next);
+  if((diff < 0) || (out >= diff))
+  {
+     /* hard wrap to offset and set mark */
+     f->f_un.f_clog.cf_next = f->f_un.f_clog.cf_offset;
+     err = pwrite(f->f_file, clog_wrap, strlen(clog_wrap), 
f->f_un.f_clog.cf_next);
+     if (err == -1)
+       return -1;
+     fsync(f->f_file);
+     f->f_un.f_clog.cf_next += err;
+  }
+  out = 0;
+
+  /* write out to circular log file */
+  err = pwritev(f->f_file,&iov[IOV_OFFSET],iovcnt - 
IOV_OFFSET,f->f_un.f_clog.cf_next);
+  if (err==-1)
+    return -1;
+  fsync(f->f_file);
+  f->f_un.f_clog.cf_next += err;
+  out += err;
+
+  return out;
+}
+
 /* Decode a symbolic name to a numeric value.  */
 int
 decode (const char *name, CODE * codetab)
--
1.7.2.5


------------------------------------------------------------------------------------------------------------

I hope it is correct in this way. For the paper i will see what can i do.

Best regards!

--
Daniel Lehne,
Dep. Development

AMK Drives and Controls Ltd.
Bulgaria / Gabrovo