usr/src/cmd/syslogd/conf.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 #include <sys/types.h>
  29 #include <sys/wait.h>
  30
  31 #include <unistd.h>
  32 #include <signal.h>
  33 #include <string.h>
  34 #include <stdlib.h>
  35 #include <stdio.h>
  36 #include <errno.h>
  37
  38 #include "conf.h"
  39
  40 #define CF_DEFSIZE      32      /* Starting table size */
  41 #define CF_GROW         2       /* Table size multiplier on grow */
  42
  43 static FILE *
  44 open_conf_pipe(const char *cmd, char *argv[], pid_t *pidp)
  45 {
  46         int pfds[2];
  47         pid_t pid;
  48         struct sigaction act;
  49
  50         /* Create a pipe and fork a child process to run the command */
  51
  52         if (pipe(pfds) == -1) {
  53                 logerror("failed to create pipe");
  54                 return (NULL);
  55         }
  56
  57         if ((pid = fork1()) == -1) {
  58                 logerror("failed to fork1");
  59                 goto err;
  60         }
  61
  62         /* If we're in the child, run the command and output to the pipe */
  63
  64         if (pid == 0) {
  65                 /*
  66                  * We must set up to ignore these signals, which may be
  67                  * propogated from the calling process.
  68                  */
  69
  70                 act.sa_handler = SIG_IGN;
  71
  72                 (void) sigaction(SIGHUP, &act, NULL);
  73                 (void) sigaction(SIGALRM, &act, NULL);
  74                 (void) sigaction(SIGUSR1, &act, NULL);
  75
  76                 (void) close(pfds[0]);
  77                 (void) close(STDOUT_FILENO);
  78
  79                 if (dup2(pfds[1], STDOUT_FILENO) == -1) {
  80                         logerror("failed to dup to stdout");
  81                         (void) close(pfds[1]);
  82                         _exit(127);
  83                 }
  84
  85                 (void) execvp(cmd, argv);
  86                 logerror("failed to parse configuration file");
  87                 _exit(127);
  88                 /*NOTREACHED*/
  89         }
  90
  91         /* If we're in the parent, open the read end of the pipe and return */
  92
  93         *pidp = pid;
  94         (void) close(pfds[1]);
  95         return (fdopen(pfds[0], "r"));
  96
  97 err:
  98         (void) close(pfds[0]);
  99         (void) close(pfds[1]);
 100         return (NULL);
 101 }
 102
 103 static void
 104 close_conf_pipe(FILE *fp, pid_t pid)
 105 {
 106         int status;
 107
 108         while (waitpid(pid, &status, 0) == -1) {
 109                 if (errno != EINTR)
 110                         break;
 111         }
 112
 113         (void) fclose(fp);
 114 }
 115
 116 static int
 117 grow_conf_file(conf_t *cf)
 118 {
 119         int ndsize = cf->cf_dsize ? cf->cf_dsize * CF_GROW : CF_DEFSIZE;
 120         void *ndtab = reallocarray(cf->cf_dtab, ndsize, sizeof (char *));
 121
 122         register char *p;
 123         int odsize, lines, i;
 124
 125         if (ndtab == NULL) {
 126                 logerror("failed to allocate config file table");
 127                 return (-1);
 128         }
 129
 130         lines = ndsize - cf->cf_dsize;
 131         odsize = cf->cf_dsize;
 132
 133         cf->cf_dtab = (char **)ndtab;
 134         cf->cf_dsize = ndsize;
 135
 136         for (i = 0; i < lines; i++) {
 137                 if ((p = (char *)malloc(BUFSIZ)) == NULL) {
 138                         logerror("failed to allocate config file buffer");
 139                         return (-1);
 140                 }
 141
 142                 cf->cf_dtab[odsize + i] = p;
 143         }
 144
 145         return (0);
 146 }
 147
 148 int
 149 conf_open(conf_t *cf, const char *cmd, char *argv[])
 150 {
 151         char *line, *p;
 152         pid_t pid;
 153         FILE *fp;
 154
 155         (void) memset(cf, 0, sizeof (conf_t));
 156
 157         if ((fp = open_conf_pipe(cmd, argv, &pid)) == NULL)
 158                 return (-1);
 159
 160         for (;;) {
 161                 /* If we need to grow the table, do so now */
 162
 163                 if (cf->cf_lines >= cf->cf_dsize) {
 164                         if (grow_conf_file(cf) == -1)
 165                                 goto err;
 166                 }
 167
 168                 line = cf->cf_dtab[cf->cf_lines];
 169
 170                 /* Read the next line, and break out if we're done */
 171
 172                 if (fgets(line, BUFSIZ, fp) == NULL)
 173                         break;
 174
 175                 /* Strip newline and bump line counter */
 176
 177                 if ((p = strchr(line, '\n')) != NULL)
 178                         *p = '\0';
 179
 180                 cf->cf_lines++;
 181         }
 182
 183         close_conf_pipe(fp, pid);
 184         return (0);
 185
 186 err:
 187         close_conf_pipe(fp, pid);
 188         return (-1);
 189 }
 190
 191 void
 192 conf_rewind(conf_t *cf)
 193 {
 194         cf->cf_ptr = 0;
 195 }
 196
 197 char *
 198 conf_read(conf_t *cf)
 199 {
 200         if (cf->cf_ptr < cf->cf_lines)
 201                 return (cf->cf_dtab[cf->cf_ptr++]);
 202
 203         return (NULL);
 204 }
 205
 206 void
 207 conf_close(conf_t *cf)
 208 {
 209         int i;
 210
 211         if (cf->cf_dtab != NULL) {
 212                 for (i = 0; i < cf->cf_dsize; i++)
 213                         free(cf->cf_dtab[i]);
 214                 free(cf->cf_dtab);
 215         }
 216 }