src/common/util-common.c


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/*
 *  util-common.c
 *
 *  Copyright (c) 2006-2014 Pacman Development Team <pacman-dev@archlinux.org>
 *
 *  This program 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; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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/>.
 */

#include <errno.h>
#include <stdlib.h>
#include <string.h>

#include "util-common.h"


/** Parse the basename of a program from a path.
* @param path path to parse basename from
*
* @return everything following the final '/'
*/
const char *mbasename(const char *path)
{
        const char *last = strrchr(path, '/');
        if(last) {
                return last + 1;
        }
        return path;
}

/** Parse the dirname of a program from a path.
* The path returned should be freed.
* @param path path to parse dirname from
*
* @return everything preceding the final '/'
*/
char *mdirname(const char *path)
{
        char *ret, *last;

        /* null or empty path */
        if(path == NULL || *path == '\0') {
                return strdup(".");
        }

        if((ret = strdup(path)) == NULL) {
                return NULL;
        }

        last = strrchr(ret, '/');

        if(last != NULL) {
                /* we found a '/', so terminate our string */
                if(last == ret) {
                        /* return "/" for root */
                        last++;
                }
                *last = '\0';
                return ret;
        }

        /* no slash found */
        free(ret);
        return strdup(".");
}

/** lstat wrapper that treats /path/dirsymlink/ the same as /path/dirsymlink.
 * Linux lstat follows POSIX semantics and still performs a dereference on
 * the first, and for uses of lstat in libalpm this is not what we want.
 * @param path path to file to lstat
 * @param buf structure to fill with stat information
 * @return the return code from lstat
 */
int llstat(char *path, struct stat *buf)
{
        int ret;
        char *c = NULL;
        size_t len = strlen(path);

        while(len > 1 && path[len - 1] == '/') {
                --len;
                c = path + len;
        }

        if(c) {
                *c = '\0';
                ret = lstat(path, buf);
                *c = '/';
        } else {
                ret = lstat(path, buf);
        }

        return ret;
}

/** Wrapper around fgets() which properly handles EINTR
 * @param s string to read into
 * @param size maximum length to read
 * @param stream stream to read from
 * @return value returned by fgets()
 */
char *safe_fgets(char *s, int size, FILE *stream)
{
        char *ret;
        int errno_save = errno, ferror_save = ferror(stream);
        while((ret = fgets(s, size, stream)) == NULL && !feof(stream)) {
                if(errno == EINTR) {
                        /* clear any errors we set and try again */
                        errno = errno_save;
                        if(!ferror_save) {
                                clearerr(stream);
                        }
                } else {
                        break;
                }
        }
        return ret;
}

#ifndef HAVE_STRNDUP
/* A quick and dirty implementation derived from glibc */
/** Determines the length of a fixed-size string.
 * @param s string to be measured
 * @param max maximum number of characters to search for the string end
 * @return length of s or max, whichever is smaller
 */
static size_t strnlen(const char *s, size_t max)
{
        register const char *p;
        for(p = s; *p && max--; ++p);
        return (p - s);
}

/** Copies a string.
 * Returned string needs to be freed
 * @param s string to be copied
 * @param n maximum number of characters to copy
 * @return pointer to the new string on success, NULL on error
 */
char *strndup(const char *s, size_t n)
{
        size_t len = strnlen(s, n);
        char *new = (char *) malloc(len + 1);

        if(new == NULL) {
                return NULL;
        }

        new[len] = '\0';
        return (char *)memcpy(new, s, len);
}
#endif

/* vim: set noet: */