usr.sbin/clog/clog.c

   1 /*-
   2  * Copyright (c) 2001
   3  *     Jeff Wheelhouse (jdw@wwwi.com)
   4  *
   5  * This code was originally developed by Jeff Wheelhouse (jdw@wwwi.com).
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistribution of source code must retail the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY JEFF WHEELHOUSE ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  19  * NO EVENT SHALL JEFF WHEELHOUSE BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING BUT NOT
  21  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
  22  * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
  23  * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  24  * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  25  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  *
  27  * $Id: clog.c,v 1.3 2001/10/02 18:51:26 jdw Exp $
  28  */
  29
  30
  31 #include <assert.h>
  32 #include <errno.h>
  33 #include <fcntl.h>
  34 #include <poll.h>
  35 #include <signal.h>
  36 #include <stdio.h>
  37 #include <stdlib.h>
  38 #include <string.h>
  39 #include <unistd.h>
  40
  41 #include <sys/mman.h>
  42 #include <sys/sched.h>
  43 #include <sys/stat.h>
  44 #include <sys/uio.h>
  45
  46
  47 #include "clog.h"
  48
  49
  50 /*
  51  *  The BUFFER_SIZE value is just used to allocate a buffer full of NULLs
  52  *  so that a new logfile can be extended to its full size.
  53  *
  54  *  Compiling with -pedantic complains when the buffer array is declared
  55  *  if I declare this as a const instead of a #define.
  56  */
  57 #define BUFFER_SIZE 16384
  58
  59 static void init_log(const char *lname, size_t size) __dead2;
  60 static void read_log(const char *lname, int optf) __dead2;
  61 static void usage(void) __dead2;
  62
  63 static const char *pname;
  64
  65 int
  66 main(int argc, char **argv)
  67 {
  68         int ch;
  69         int init = 0;
  70         int size = 0;
  71         int optf = 0;
  72
  73         pname = argv[0];
  74
  75         while ((ch = getopt(argc, argv, "fis:")) != -1)
  76                 switch(ch) {
  77                 case 'i':
  78                         init = 1;
  79                         break;
  80                 case 's':
  81                         size = atol(optarg);
  82                         if (size==0) usage();
  83                         break;
  84                 case 'f':
  85                         optf = 1;
  86                 }
  87
  88         if ((size>0)&&(init==0)) {
  89                 fprintf(stderr,"%s: WARNING: -s argument ignored without -i.\n",pname);
  90                 size = 0;
  91         }
  92         if (argv[optind]==NULL) {
  93                 fprintf(stderr,"%s: ERROR: log_file argument must be specified.\n",pname);
  94                 usage();
  95         }
  96         if ((init==1)&&(size==0)) {
  97                 fprintf(stderr,"%s: ERROR: -i argument requires -s.\n",pname);
  98                 usage();
  99         }
 100         if ((init==1)&&(optf==1)) {
 101                 fprintf(stderr,"%s: ERROR: flags -f and -i are incompatible.\n",pname);
 102                 usage();
 103         }
 104
 105         if (init==1) init_log(argv[optind],size);
 106         /* if (optf==1) follow_log(artv[optind]); */
 107         read_log(argv[optind],optf);
 108
 109         return 0;
 110 }
 111
 112
 113 static void
 114 usage(void)
 115 {
 116   fprintf(stderr,"usage: %s [-i -s log_size] [ -f ] log_file\n",pname);
 117   exit(1);
 118 }
 119
 120
 121 static void
 122 read_log(const char *lname, int optf)
 123 {
 124         int fd;
 125         struct stat sb;
 126         struct clog_footer *pcf;
 127         char *pbuffer;
 128         struct iovec iov[2];
 129         int iovcnt = 0;
 130         uint32_t start = 0;
 131         uint32_t next;
 132         struct pollfd pfd;
 133
 134         pfd.fd = -1;
 135
 136         fd = open(lname,O_RDONLY);
 137         if (fd==-1) {
 138                 fprintf(stderr,"%s: ERROR: could not open %s (%s)\n",pname,lname,strerror(errno));
 139                 exit(11);
 140         }
 141
 142         if (fstat(fd,&sb)==-1) {
 143                 fprintf(stderr,"%s: ERROR: could not stat %s (%s)\n",pname,lname,strerror(errno));
 144                 exit(13);
 145         }
 146         pbuffer = mmap(NULL,sb.st_size,PROT_READ,MAP_SHARED,fd,0);
 147         if (pbuffer==NULL) {
 148                 fprintf(stderr,"%s: ERROR: could not mmap %s body (%s)\n",pname,lname,strerror(errno));
 149                 exit(14);
 150         }
 151         pcf = (struct clog_footer*)(pbuffer + sb.st_size - sizeof(struct clog_footer));
 152
 153         if (pcf->cf_wrap==1) start = pcf->cf_next + 1;
 154         while(1) {
 155                 while(pcf->cf_lock==1) sched_yield();
 156                 next = pcf->cf_next;
 157                 iovcnt = 0;
 158                 if (start>next) {
 159                         iov[iovcnt].iov_base = pbuffer + start;
 160                         iov[iovcnt++].iov_len = pcf->cf_max - start;
 161                         start = 0;
 162                 }
 163                 iov[iovcnt].iov_base = pbuffer + start;
 164                 iov[iovcnt++].iov_len = next - start;
 165                 if (writev(1,iov,iovcnt)==-1) {
 166                         fprintf(stderr,"%s: ERROR: could not write output (%s)\n",pname,strerror(errno));
 167                         exit(15);
 168                 }
 169                 start = next;
 170                 if (optf==0) break;
 171                 if (poll(&pfd,1,50)==-1) {
 172                         fprintf(stderr,"%s: ERROR: could not poll (%s)\n",pname,strerror(errno));
 173                         exit(16);
 174                 }
 175         }
 176
 177         munmap(pbuffer,sb.st_size);
 178         close(fd);
 179
 180         exit(0);
 181 }
 182
 183
 184 static void
 185 init_log(const char *lname, size_t size)
 186 {
 187         int fd;
 188         size_t fill = size;
 189         char buffer[BUFFER_SIZE];
 190         struct clog_footer cf;
 191
 192         memcpy(&cf.cf_magic,MAGIC_CONST,4);
 193         cf.cf_max = size - sizeof(struct clog_footer);
 194
 195         memset(buffer,0,BUFFER_SIZE);
 196
 197         fd = open(lname,O_RDWR|O_CREAT,0666);
 198         if (fd==-1) {
 199                 fprintf(stderr,"%s: ERROR: could not open %s (%s)\n",pname,lname,strerror(errno));
 200                 exit(2);
 201         }
 202         if (ftruncate(fd,(off_t)0)==-1) {
 203                 fprintf(stderr,"%s: ERROR: could not truncate %s (%s)\n",pname,lname,strerror(errno));
 204                 exit(3);
 205         }
 206
 207         while(fill>BUFFER_SIZE) {
 208                 if (write(fd,buffer,BUFFER_SIZE)==-1){
 209                         fprintf(stderr,"%s: ERROR: could not write %s (%s)\n",pname,lname,strerror(errno));
 210                         exit(4);
 211                 }
 212                 fill -= BUFFER_SIZE;
 213         }
 214         assert(fill<=BUFFER_SIZE);
 215         if (fill>0) {
 216                 if (write(fd,buffer,fill)==-1) {
 217                         fprintf(stderr,"%s: ERROR: could not write %s (%s)\n",pname,lname,strerror(errno));
 218                         exit(5);
 219                 }
 220         }
 221         if (lseek(fd,-(off_t)(sizeof(struct clog_footer)),SEEK_END)==-1) {
 222                 fprintf(stderr,"%s: ERROR: could not seek in %s (%s)\n",pname,lname,strerror(errno));
 223                 exit(6);
 224         }
 225         if (write(fd,&cf,sizeof(cf))==-1) {
 226                 fprintf(stderr,"%s: ERROR: could not write magic in %s (%s)\n",pname,lname,strerror(errno));
 227                 exit(7);
 228         }
 229         close(fd);
 230         exit(0);
 231 }