/*      $NetBSD: filter.c,v 1.20 2023/08/26 14:59:44 rillig Exp $       */

/*
 * Copyright (c) 1980, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)filter.c    8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: filter.c,v 1.20 2023/08/26 14:59:44 rillig Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <pwd.h>
#include <unistd.h>
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include "error.h"
#include "pathnames.h"

static const char *lint_libs[] = {
        IG_FILE1,
        IG_FILE2,
        IG_FILE3,
        IG_FILE4,
        NULL
};

static int lexsort(const void *, const void *);
static int search_ignore(const char *);

/*
 * Read the file ERRORNAME of the names of functions in lint
 * to ignore complaints about.
 */
void
getignored(const char *auxname)
{
        int i;
        FILE *fyle;
        char inbuffer[256];
        uid_t uid;
        char filename[MAXPATHLEN];
        const char *username;
        struct passwd *passwdentry;

        nignored = 0;
        if (auxname == 0) {     /* use the default */
                if ((username = getlogin()) == NULL) {
                        username = "Unknown";
                        uid = getuid();
                        if ((passwdentry = getpwuid(uid)) == NULL) {
                                return;
                        }
                } else {
                        if ((passwdentry = getpwnam(username)) == NULL)
                                return;
                }
                strlcpy(filename, passwdentry->pw_dir, sizeof(filename));
                (void)strlcat(filename, ERRORNAME, sizeof(filename));
        } else
                (void)strlcpy(filename, auxname, sizeof(filename));
#ifdef FULLDEBUG
        printf("Opening file \"%s\" to read names to ignore.\n",
                filename);
#endif
        if ((fyle = fopen(filename, "r")) == NULL) {
#ifdef FULLDEBUG
                fprintf(stderr, "%s: Can't open file \"%s\"\n",
                        processname, filename);
#endif
                return;
        }

        /*
         * Make the first pass through the file, counting lines
         */
        for (nignored = 0;
             fgets(inbuffer, sizeof(inbuffer)-1, fyle) != NULL; nignored++)
                continue;
        names_ignored = Calloc(nignored+1, sizeof (char *));
        rewind(fyle);
        for (i=0; i < nignored &&
                  (fgets (inbuffer, sizeof(inbuffer)-1, fyle) != NULL); i++) {
                names_ignored[i] = Strdup(inbuffer);
                (void)substitute(names_ignored[i], '\n', '\0');
        }
        qsort(names_ignored, nignored, sizeof *names_ignored, lexsort);
        fclose(fyle);
#ifdef FULLDEBUG
        printf("Names to ignore follow.\n");
        for (i=0; i < nignored; i++) {
                printf("\tIgnore: %s\n", names_ignored[i]);
        }
#endif
}

static int
lexsort(const void *c1, const void *c2)
{
        const char *const *cpp1;
        const char *const *cpp2;

        cpp1 = c1;
        cpp2 = c2;
        return strcmp(*cpp1, *cpp2);
}

static int
search_ignore(const char *key)
{
        int ub, lb;
        int halfway;
        int order;

        if (nignored == 0)
                return -1;
        for (lb = 0, ub = nignored - 1; ub >= lb; ) {
                halfway = (ub + lb)/2;
                if ( (order = strcmp(key, names_ignored[halfway])) == 0)
                        return halfway;
                if (order < 0)  /* key is less than probe, throw away above */
                        ub = halfway - 1;
                 else
                        lb = halfway + 1;
        }
        return -1;
}

/*
 * Tell if the error text is to be ignored.
 * The error must have been canonicalized, with
 * the file name the zeroth entry in the errorv,
 * and the linenumber the second.
 * Return the new categorization of the error class.
 */
Errorclass
discardit(Eptr errorp)
{
        int i;
        Errorclass errorclass = errorp->error_e_class;

        switch (errorclass) {
                case C_SYNC:
                case C_NONSPEC:
                case C_UNKNOWN: return errorclass;
                default:        ;
        }
        if (errorp->error_lgtext < 2) {
                return C_NONSPEC;
        }
        if (errorp->error_language == INLINT) {
                if (errorclass != C_NONSPEC) {  /* no file */
                        for (i=0; lint_libs[i] != 0; i++) {
                                if (strcmp(errorp->error_text[0], lint_libs[i]) == 0) {
                                        return C_DISCARD;
                                }
                        }
                }
                /* check if the argument to the error message is to be ignored */
                if (ispunct((unsigned char)lastchar(errorp->error_text[2])))
                        clob_last(errorp->error_text[2], '\0');
                if (search_ignore(errorp->error_text[errorclass == C_NONSPEC ? 0 : 2]) >= 0) {
                        return C_NULLED;
                }
        }
        return errorclass;
}