PathCheck Example Source Code

The source code for this example is located in pcheck.c in the plugins/nsapi/examples subdirectory within the server root directory.

#include "nsapi.h"
/*     Set to NULL to prevent problems with people not calling
    acf-init */
static char **hosts = NULL;
#include <stdio.h>
#include "base/daemon.h"
#include "base/util.h"      /* util_sprintf */
#include "frame/log.h"      /* log_error */
#include "frame/protocol.h" /* protocol_status */
/* The longest line we’ll allow in an access control file */
#define MAX_ACF_LINE 256
/* Used to free static array on restart */
#ifdef __cplusplus
extern "C"
#endif
NSAPI_PUBLIC void acf_free(void *unused)
{
    register int x;
    for(x = 0; hosts[x]; ++x)
        FREE(hosts[x]);
    FREE(hosts);
    hosts = NULL;
}
#ifdef __cplusplus
extern "C"
#endif
NSAPI_PUBLIC int acf_init(pblock *pb, Session *sn, Request *rq)
{
    /* Parameter */
    char *acf_file = pblock_findval("file", pb);
    /* Working variables */
    int num_hosts;
    FILE *f;
    char err[MAGNUS_ERROR_LEN];
    char buf[MAX_ACF_LINE];
    /*     Check usage. Note that Init functions have special
         error logging */
    if(!acf_file) {
        util_sprintf(err, "missing parameter to acf_init
             (need file)");
        pblock_nvinsert("error", err, pb);
        return REQ_ABORTED;
    }
    f = fopen(acf_file, "r");
    /* Did we open it? */
    if(!f) {
        util_sprintf(err, "can’t open access control file %s (%s)",
            acf_file, system_errmsg());
        pblock_nvinsert("error", err, pb);
        return REQ_ABORTED;
    }
    /* Initialize hosts array */
    num_hosts = 0;
    hosts = (char **) MALLOC(1 * sizeof(char *));
    hosts[0] = NULL;
    while(fgets(buf, MAX_ACF_LINE, f)) {
        /* Blast linefeed that stdio helpfully leaves on there */
        buf[strlen(buf) - 1] = ’\\0’;
        hosts = (char **) REALLOC(hosts, (num_hosts + 2) *
             sizeof(char *));
        hosts[num_hosts++] = STRDUP(buf);
        hosts[num_hosts] = NULL;
    }
    fclose(f);
    /* At restart, free hosts array */
    daemon_atrestart(acf_free, NULL);
    return REQ_PROCEED
}
#ifdef __cplusplus
extern "C"
#endif
NSAPI_PUBLIC int restrict_by_acf(pblock *pb, Session *sn, Request *rq)
{
    /* No parameters */
    /* Working variables */
    char *remip = pblock_findval("ip", sn->client);
    register int x;
    if(!hosts) {
        log_error(LOG_MISCONFIG, "restrict-by-acf", sn, rq,
             "restrict-by-acf called without call to acf-init");
        /*     When we abort, the default status code is 500 Server
             Error */
        return REQ_ABORTED;
    }
    for(x = 0; hosts[x] != NULL; ++x) {
        /* If they’re on the list, they’re allowed */
        if(!strcmp(remip, hosts[x]))
        return REQ_NOACTION;
    }
    /* Set response code to forbidden and return an error. */
    protocol_status(sn, rq, PROTOCOL_FORBIDDEN, NULL);
    return REQ_ABORTED;
}