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  * $DragonFly: src/usr.sbin/clog/clog.c,v 1.4 2007/06/26 23:30:05 josepht Exp $
  29  */
  30
  31
  32 #include <assert.h>
  33 #include <errno.h>
  34 #include <fcntl.h>
  35 #include <poll.h>
  36 #include <signal.h>
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include <sys/mman.h>
  43 #include <sys/sched.h>
  44 #include <sys/stat.h>
  45 #include <sys/uio.h>
  46
  47
  48 #include "clog.h"
  49
  50
  51 /*
  52  *  The BUFFER_SIZE value is just used to allocate a buffer full of NULLs
  53  *  so that a new logfile can be extended to its full size.
  54  *
  55  *  Compiling with -pedantic complains when the buffer array is declared
  56  *  if I declare this as a const instead of a #define.
  57  */
  58 #define BUFFER_SIZE 16384
  59
  60 void init_log(const char *lname, size_t size);
  61 void read_log(const char *lname, int optf);
  62 void usage(void);
  63
  64 const char *pname;
  65
  66 int
  67 main(int argc, char **argv)
  68 {
  69         int ch;
  70         int init = 0;
  71         int size = 0;
  72         int optf = 0;
  73
  74         pname = argv[0];
  75
  76         while ((ch = getopt(argc, argv, "fis:")) != -1)
  77                 switch(ch) {
  78                 case 'i':
  79                         init = 1;
  80                         break;
  81                 case 's':
  82                         size = atol(optarg);
  83                         if (size==0) usage();
  84                         break;
  85                 case 'f':
  86                         optf = 1;
  87                 }
  88
  89         if ((size>0)&&(init==0)) {
  90                 fprintf(stderr,"%s: WARNING: -s argument ignored without -i.\n",pname);
  91                 size = 0;
  92         }
  93         if (argv[optind]==NULL) {
  94                 fprintf(stderr,"%s: ERROR: log_file argument must be specified.\n",pname);
  95                 usage();
  96         }
  97         if ((init==1)&&(size==0)) {
  98                 fprintf(stderr,"%s: ERROR: -i argument requires -s.\n",pname);
  99                 usage();
 100         }
 101         if ((init==1)&&(optf==1)) {
 102                 fprintf(stderr,"%s: ERROR: flags -f and -i are incompatible.\n",pname);
 103                 usage();
 104         }
 105
 106         if (init==1) init_log(argv[optind],size);
 107         /* if (optf==1) follow_log(artv[optind]); */
 108         read_log(argv[optind],optf);
 109
 110         return 0;
 111 }
 112
 113
 114 void
 115 usage(void)
 116 {
 117   fprintf(stderr,"usage: %s [-i -s log_size] [ -f ] log_file\n",pname);
 118   exit(1);
 119 }
 120
 121
 122 void
 123 read_log(const char *lname, int optf)
 124 {
 125         int fd;
 126         struct stat sb;
 127         struct clog_footer *pcf;
 128         char *pbuffer;
 129         struct iovec iov[2];
 130         int iovcnt = 0;
 131         uint32_t start = 0;
 132         uint32_t next;
 133         struct pollfd pfd;
 134
 135         pfd.fd = -1;
 136
 137         fd = open(lname,O_RDONLY);
 138         if (fd==-1) {
 139                 fprintf(stderr,"%s: ERROR: could not open %s (%s)\n",pname,lname,strerror(errno));
 140                 exit(11);
 141         }
 142
 143         if (fstat(fd,&sb)==-1) {
 144                 fprintf(stderr,"%s: ERROR: could not stat %s (%s)\n",pname,lname,strerror(errno));
 145                 exit(13);
 146         }
 147         pbuffer = mmap(NULL,sb.st_size,PROT_READ,MAP_SHARED,fd,0);
 148         if (pbuffer==NULL) {
 149                 fprintf(stderr,"%s: ERROR: could not mmap %s body (%s)\n",pname,lname,strerror(errno));
 150                 exit(14);
 151         }
 152         pcf = (struct clog_footer*)(pbuffer + sb.st_size - sizeof(struct clog_footer));
 153
 154         if (pcf->cf_wrap==1) start = pcf->cf_next + 1;
 155         while(1) {
 156                 while(pcf->cf_lock==1) sched_yield();
 157                 next = pcf->cf_next;
 158                 iovcnt = 0;
 159                 if (start>next) {
 160                         iov[iovcnt].iov_base = pbuffer + start;
 161                         iov[iovcnt++].iov_len = pcf->cf_max - start;
 162                         start = 0;
 163                 }
 164                 iov[iovcnt].iov_base = pbuffer + start;
 165                 iov[iovcnt++].iov_len = next - start;
 166                 if (writev(1,iov,iovcnt)==-1) {
 167                         fprintf(stderr,"%s: ERROR: could not write output (%s)\n",pname,strerror(errno));
 168                         exit(15);
 169                 }
 170                 start = next;
 171                 if (optf==0) break;
 172                 if (poll(&pfd,1,50)==-1) {
 173                         fprintf(stderr,"%s: ERROR: could not poll (%s)\n",pname,strerror(errno));
 174                         exit(16);
 175                 }
 176         }
 177
 178         munmap(pbuffer,sb.st_size);
 179         close(fd);
 180
 181         exit(0);
 182 }
 183
 184
 185 void
 186 init_log(const char *lname, size_t size)
 187 {
 188         int fd;
 189         size_t fill = size;
 190         char buffer[BUFFER_SIZE];
 191         struct clog_footer cf;
 192
 193         memcpy(&cf.cf_magic,MAGIC_CONST,4);
 194         cf.cf_max = size - sizeof(struct clog_footer);
 195
 196         memset(buffer,0,BUFFER_SIZE);
 197
 198         fd = open(lname,O_RDWR|O_CREAT,0666);
 199         if (fd==-1) {
 200                 fprintf(stderr,"%s: ERROR: could not open %s (%s)\n",pname,lname,strerror(errno));
 201                 exit(2);
 202         }
 203         if (ftruncate(fd,(off_t)0)==-1) {
 204                 fprintf(stderr,"%s: ERROR: could not truncate %s (%s)\n",pname,lname,strerror(errno));
 205                 exit(3);
 206         }
 207
 208         while(fill>BUFFER_SIZE) {
 209                 if (write(fd,buffer,BUFFER_SIZE)==-1){
 210                         fprintf(stderr,"%s: ERROR: could not write %s (%s)\n",pname,lname,strerror(errno));
 211                         exit(4);
 212                 }
 213                 fill -= BUFFER_SIZE;
 214         }
 215         assert(fill<=BUFFER_SIZE);
 216         if (fill>0) {
 217                 if (write(fd,buffer,fill)==-1) {
 218                         fprintf(stderr,"%s: ERROR: could not write %s (%s)\n",pname,lname,strerror(errno));
 219                         exit(5);
 220                 }
 221         }
 222         if (lseek(fd,-(off_t)(sizeof(struct clog_footer)),SEEK_END)==-1) {
 223                 fprintf(stderr,"%s: ERROR: could not seek in %s (%s)\n",pname,lname,strerror(errno));
 224                 exit(6);
 225         }
 226         if (write(fd,&cf,sizeof(cf))==-1) {
 227                 fprintf(stderr,"%s: ERROR: could not write magic in %s (%s)\n",pname,lname,strerror(errno));
 228                 exit(7);
 229         }
 230         close(fd);
 231         exit(0);
 232 }
 233
 234