filepath.c

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/*
 * Copyright 2010 Vincent Sanders <vince@kyllikki.org>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
/**
 * \file
 * Provides utility functions for finding readable files.
 *
 * These functions are intended to make finding resource files more
 *  straightforward.
 */
 
#include <sys/types.h>
#include <sys/stat.h>
#include <stdarg.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
 
#include "utils/dirent.h" /** \todo why is this necessary for atari to get PATH_MAX and is there a better way */
#include "utils/utils.h"
#include "utils/config.h"
#include "utils/filepath.h"
 
/** maximum number of elements in the resource vector */
#define MAX_RESPATH 128
 
/* exported interface documented in filepath.h */
char *filepath_vsfindfile(char *str, const char *format, va_list ap)
{
        char *realpathname;
        char *pathname;
        int len;
 
        pathname = malloc(PATH_MAX);
        if (pathname == NULL)
                return NULL; /* unable to allocate memory */
 
        len = vsnprintf(pathname, PATH_MAX, format, ap);
 
        if ((len < 0) || (len >= PATH_MAX)) {
                /* error or output exceeded PATH_MAX length so
                 * operation is doomed to fail.
                 */
                free(pathname);
                return NULL;
        }
 
        realpathname = realpath(pathname, str);
 
        free(pathname);
 
        if (realpathname != NULL) {
                /* sucessfully expanded pathname */
                if (access(realpathname, R_OK) != 0) {
                        /* unable to read the file */
                        return NULL;
                }
        }
 
        return realpathname;
}
 
 
/* exported interface documented in filepath.h */
char *filepath_sfindfile(char *str, const char *format, ...)
{
        va_list ap;
        char *ret;
 
        va_start(ap, format);
        ret = filepath_vsfindfile(str, format, ap);
        va_end(ap);
 
        return ret;
}
 
 
/* exported interface documented in filepath.h */
char *filepath_findfile(const char *format, ...)
{
        char *ret;
        va_list ap;
 
        va_start(ap, format);
        ret = filepath_vsfindfile(NULL, format, ap);
        va_end(ap);
 
        return ret;
}
 
/* exported interface documented in filepath.h */
char *filepath_sfind(char **respathv, char *filepath, const char *filename)
{
        int respathc = 0;
 
        if ((respathv == NULL) || (respathv[0] == NULL) || (filepath == NULL))
                return NULL;
 
        while (respathv[respathc] != NULL) {
                if (filepath_sfindfile(filepath, "%s/%s", respathv[respathc], filename) != NULL) {
                        return filepath;
                }
 
                respathc++;
        }
 
        return NULL;
}
 
 
/* exported interface documented in filepath.h */
char *filepath_find(char **respathv, const char *filename)
{
        char *ret;
        char *filepath;
 
        if ((respathv == NULL) || (respathv[0] == NULL))
                return NULL;
 
        filepath = malloc(PATH_MAX);
        if (filepath == NULL)
                return NULL;
 
        ret = filepath_sfind(respathv, filepath, filename);
 
        if (ret == NULL)
                free(filepath);
 
        return ret;
}
 
 
/* exported interface documented in filepath.h */
char *
filepath_sfinddef(char **respathv,
                  char *filepath,
                  const char *filename,
                  const char *def)
{
        char t[PATH_MAX];
        char *ret;
 
        if ((respathv == NULL) || (respathv[0] == NULL) || (filepath == NULL))
                return NULL;
 
        ret = filepath_sfind(respathv, filepath, filename);
 
        if ((ret == NULL) && (def != NULL)) {
                /* search failed, return the path specified */
                ret = filepath;
                if (def[0] == '~') {
                        snprintf(t, PATH_MAX, "%s/%s/%s", getenv("HOME"), def + 1, filename);
                } else {
                        snprintf(t, PATH_MAX, "%s/%s", def, filename);
                }
                if (realpath(t, ret) == NULL) {
                        strncpy(ret, t, PATH_MAX);
                }
 
        }
        return ret;
}
 
 
/* exported interface documented in filepath.h */
char **
filepath_generate(char * const *pathv, const char * const *langv)
{
        char **respath; /* resource paths vector */
        int pathc = 0;
        int langc = 0;
        int respathc = 0;
        struct stat dstat;
        char *tmppath;
        int tmppathlen;
 
        respath = calloc(MAX_RESPATH, sizeof(char *));
 
        while ((respath != NULL) &&
               (pathv[pathc] != NULL)) {
                if ((stat(pathv[pathc], &dstat) == 0) &&
                    S_ISDIR(dstat.st_mode)) {
                        /* path element exists and is a directory */
                        langc = 0;
                        while (langv[langc] != NULL) {
                                tmppathlen = snprintf(NULL,
                                                      0,
                                                      "%s/%s",
                                                      pathv[pathc],
                                                      langv[langc]);
                                tmppath = malloc(tmppathlen + 1);
                                if (tmppath == NULL) {
                                        break;
                                }
                                snprintf(tmppath,
                                         tmppathlen + 1,
                                         "%s/%s",
                                         pathv[pathc],
                                         langv[langc]);
 
                                if ((stat(tmppath, &dstat) == 0) &&
                                    S_ISDIR(dstat.st_mode)) {
                                        /* path element exists and is a directory */
                                        respath[respathc++] = tmppath;
                                } else {
                                        free(tmppath);
                                }
 
                                langc++;
                        }
                        respath[respathc++] = strdup(pathv[pathc]);
                }
                pathc++;
        }
        return respath;
}
 
 
/**
 * expand ${} in a string into environment variables.
 *
 * @param path The pathname to expand.
 * @param pathlen The length of the path element.
 * @return A string with the expanded path or NULL on empty expansion or error.
 */
static char *
expand_path(const char *path, int pathlen)
{
        char *exp;
        int explen;
        int cstart = -1;
        int cloop = 0;
        char *envv;
        int envlen;
        int replen; /* length of replacement */
 
        exp = malloc(pathlen + 1);
        if (exp == NULL)
                return NULL;
 
        memcpy(exp, path, pathlen);
        exp[pathlen] = 0;
 
        explen = pathlen;
 
        while (exp[cloop] != 0) {
                if ((exp[cloop] == '$') &&
                    (exp[cloop + 1] == '{')) {
                        cstart = cloop;
                        cloop++;
                }
 
                if ((cstart != -1) &&
                    (exp[cloop] == '}')) {
                        replen = cloop - cstart;
                        exp[cloop] = 0;
                        envv = getenv(exp + cstart + 2);
                        if (envv == NULL) {
                                memmove(exp + cstart,
                                        exp + cloop + 1,
                                        explen - cloop);
                                explen -= replen;
                        } else {
                                char *tmp;
                                envlen = strlen(envv);
                                tmp = realloc(exp, explen + envlen - replen);
                                if (tmp == NULL) {
                                        free(exp);
                                        return NULL;
                                }
                                exp = tmp;
                                memmove(exp + cstart + envlen,
                                        exp + cloop + 1,
                                        explen - cloop );
                                memmove(exp + cstart, envv, envlen);
                                explen += envlen - replen;
                        }
                        cloop -= replen;
                        cstart = -1;
                }
 
                cloop++;
        }
 
        if (explen == 1) {
                free(exp);
                exp = NULL;
        }
 
        return exp;
}
 
 
/* exported interface documented in filepath.h */
char **
filepath_path_to_strvec(const char *path)
{
        char **strvec;
        int strc = 0;
        const char *estart; /* path element start */
        const char *eend; /* path element end */
        int elen;
 
        strvec = calloc(MAX_RESPATH, sizeof(char *));
        if (strvec == NULL)
                return NULL;
 
        estart = eend = path;
 
        while (strc < (MAX_RESPATH - 2)) {
                while ( (*eend != 0) && (*eend != ':') )
                        eend++;
                elen = eend - estart;
 
                if (elen > 1) {
                        /* more than an empty colon */
                        strvec[strc] = expand_path(estart, elen);
                        if (strvec[strc] != NULL) {
                                /* successfully expanded an element */
                                strc++;
                        }
                }
 
                /* skip colons */
                while (*eend == ':')
                        eend++;
 
                /* check for termination */
                if (*eend == 0)
                        break;
 
                estart = eend;
        }
        return strvec;
}
 
 
/* exported interface documented in filepath.h */
void filepath_free_strvec(char **pathv)
{
        int p = 0;
 
        while (pathv[p] != NULL) {
                free(pathv[p++]);
        }
        free(pathv);
}