cmd/syslogd/conf.c

	conf.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 *  Copyright (c) 1997-2000 by Sun Microsystems, Inc.
 *  All rights reserved.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <sys/types.h>
#include <sys/wait.h>

#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>

#include "conf.h"

#define CF_DEFSIZE  32  /* Starting table size */
#define CF_GROW     2   /* Table size multiplier on grow */

extern void logerror(char *);

static FILE *
open_conf_pipe(const char *cmd, char *argv[], pid_t *pidp)
{
    int pfds[2];
    pid_t pid;
    struct sigaction act;

    /* Create a pipe and fork a child process to run the command */

    if (pipe(pfds) == -1) {
        logerror("failed to create pipe");
        return (NULL);
    }

    if ((pid = fork1()) == -1) {
        logerror("failed to fork1");
        goto err;
    }

    /* If we're in the child, run the command and output to the pipe */

    if (pid == 0) {
        /*
         * We must set up to ignore these signals, which may be
         * propogated from the calling process.
         */

        act.sa_handler = SIG_IGN;

        (void) sigaction(SIGHUP, &act, NULL);
        (void) sigaction(SIGALRM, &act, NULL);
        (void) sigaction(SIGUSR1, &act, NULL);

        (void) close(pfds[0]);
        (void) close(STDOUT_FILENO);

        if (dup2(pfds[1], STDOUT_FILENO) == -1) {
            logerror("failed to dup to stdout");
            (void) close(pfds[1]);
            _exit(127);
        }

        (void) execvp(cmd, argv);
        logerror("failed to parse configuration file");
        _exit(127);
        /*NOTREACHED*/
    }

    /* If we're in the parent, open the read end of the pipe and return */

    *pidp = pid;
    (void) close(pfds[1]);
    return (fdopen(pfds[0], "r"));

err:
    (void) close(pfds[0]);
    (void) close(pfds[1]);
    return (NULL);
}

static void
close_conf_pipe(FILE *fp, pid_t pid)
{
    int status;

    while (waitpid(pid, &status, 0) == -1) {
        if (errno != EINTR)
            break;
    }

    (void) fclose(fp);
}

static int
grow_conf_file(conf_t *cf)
{
    int ndsize = cf->cf_dsize ? cf->cf_dsize * CF_GROW : CF_DEFSIZE;
    void *ndtab = realloc(cf->cf_dtab, sizeof (char *) * ndsize);

    register char *p;
    int odsize, lines, i;

    if (ndtab == NULL) {
        logerror("failed to allocate config file table");
        return (-1);
    }

    lines = ndsize - cf->cf_dsize;
    odsize = cf->cf_dsize;

    cf->cf_dtab = (char **)ndtab;
    cf->cf_dsize = ndsize;

    for (i = 0; i < lines; i++) {
        if ((p = (char *)malloc(BUFSIZ)) == NULL) {
            logerror("failed to allocate config file buffer");
            return (-1);
        }

        cf->cf_dtab[odsize + i] = p;
    }

    return (0);
}

int
conf_open(conf_t *cf, const char *cmd, char *argv[])
{
    char *line, *p;
    pid_t pid;
    FILE *fp;

    (void) memset(cf, 0, sizeof (conf_t));

    if ((fp = open_conf_pipe(cmd, argv, &pid)) == NULL)
        return (-1);

    for (;;) {
        /* If we need to grow the table, do so now */

        if (cf->cf_lines >= cf->cf_dsize) {
            if (grow_conf_file(cf) == -1)
                goto err;
        }

        line = cf->cf_dtab[cf->cf_lines];

        /* Read the next line, and break out if we're done */

        if (fgets(line, BUFSIZ, fp) == NULL)
            break;

        /* Strip newline and bump line counter */

        if ((p = strchr(line, '\n')) != NULL)
            *p = '\0';

        cf->cf_lines++;
    }

    close_conf_pipe(fp, pid);
    return (0);

err:
    close_conf_pipe(fp, pid);
    return (-1);
}

void
conf_rewind(conf_t *cf)
{
    cf->cf_ptr = 0;
}

char *
conf_read(conf_t *cf)
{
    if (cf->cf_ptr < cf->cf_lines)
        return (cf->cf_dtab[cf->cf_ptr++]);

    return (NULL);
}

void
conf_close(conf_t *cf)
{
    int i;

    if (cf->cf_dtab != NULL) {
        for (i = 0; i < cf->cf_dsize; i++)
            free(cf->cf_dtab[i]);
        free(cf->cf_dtab);
    }
}