utils.c

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/* utility functions
 *
 * This file is part of nsgenbind.
 * Published under the MIT License,
 *                http://www.opensource.org/licenses/mit-license.php
 * Copyright 2015 Vincent Sanders <vince@netsurf-browser.org>
 */
 
#include <stdio.h>
#include <string.h>
#include <stdbool.h>
#include <errno.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
 
#include "options.h"
#include "utils.h"
 
/* exported function documented in utils.h */
char *genb_fpath(const char *fname)
{
        char *fpath;
        int fpathl;
 
        fpathl = strlen(options->outdirname) + strlen(fname) + 2;
        fpath = malloc(fpathl);
        snprintf(fpath, fpathl, "%s/%s", options->outdirname, fname);
 
        return fpath;
}
 
static char *genb_fpath_tmp(const char *fname)
{
        char *fpath;
        int fpathl;
 
        fpathl = strlen(options->outdirname) + strlen(fname) + 3;
        fpath = malloc(fpathl);
        snprintf(fpath, fpathl, "%s/%s.%d", options->outdirname, fname, getpid());
 
        return fpath;
}
 
/* exported function documented in utils.h */
FILE *genb_fopen(const char *fname, const char *mode)
{
        char *fpath;
        FILE *filef;
 
        if (options->dryrun) {
                fpath = strdup("/dev/null");
        } else {
                fpath = genb_fpath(fname);
        }
 
        filef = fopen(fpath, mode);
        if (filef == NULL) {
                fprintf(stderr, "Error: unable to open file %s (%s)\n",
                        fpath, strerror(errno));
                free(fpath);
                return NULL;
        }
        free(fpath);
 
        return filef;
}
 
/* exported function documented in utils.h */
FILE *genb_fopen_tmp(const char *fname)
{
        char *fpath;
        FILE *filef;
 
        if (options->dryrun) {
                fpath = strdup("/dev/null");
        } else {
                fpath = genb_fpath_tmp(fname);
        }
 
        filef = fopen(fpath, "w+");
        if (filef == NULL) {
                fprintf(stderr, "Error: unable to open file %s (%s)\n",
                        fpath, strerror(errno));
                free(fpath);
                return NULL;
        }
        free(fpath);
 
        return filef;
}
 
int genb_fclose_tmp(FILE *filef_tmp, const char *fname)
{
        char *fpath;
        char *tpath;
        FILE *filef;
        char tbuf[1024];
        char fbuf[1024];
        size_t trd;
        size_t frd;
 
        if (options->dryrun) {
                fclose(filef_tmp);
                return 0;
        }
 
        fpath = genb_fpath(fname);
        tpath = genb_fpath_tmp(fname);
 
        filef = fopen(fpath, "r");
        if (filef == NULL) {
                /* unable to open target file for comparison */
 
                fclose(filef_tmp); /*  close tmpfile */
 
                remove(fpath);
                rename(tpath, fpath);
        } else {
                rewind(filef_tmp);
 
                frd = fread(fbuf, 1, 1024, filef);
                while (frd != 0) {
                        trd = fread(tbuf, 1, frd, filef_tmp);
                        if ((trd != frd) ||
                            (memcmp(tbuf, fbuf, trd) != 0)) {
                                /* file doesnt match */
                                fclose(filef_tmp);
                                fclose(filef);
 
                                remove(fpath);
                                rename(tpath, fpath);
 
                                goto close_done;
                        }
 
                        frd = fread(fbuf, 1, 1024, filef);
                }
 
                /* was the same kill temporary file */
                fclose(filef_tmp);
                fclose(filef);
                remove(tpath);
        }
 
close_done:
        free(fpath);
        free(tpath);
 
        return 0;
}
 
 
#ifdef NEED_STRNDUP
 
char *strndup(const char *s, size_t n)
{
        size_t len;
        char *s2;
 
        for (len = 0; len != n && s[len]; len++)
                continue;
 
        s2 = malloc(len + 1);
        if (!s2)
                return 0;
 
        memcpy(s2, s, len);
        s2[len] = 0;
        return s2;
}
 
#endif