cosmopolitan/libc/calls/hefty/replaceuser.c

50 lines
2.6 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney │
│ │
│ 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; version 2 of the License. │
│ │
│ 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, write to the Free Software │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
│ 02110-1301 USA │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/bits/safemacros.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/calls/calls.h"
/**
* Replaces tilde in path w/ user home folder.
*
* @param path is NULL propagating
* @return must be free()'d
*/
char *replaceuser(const char *path) {
char *res, *p;
const char *home;
size_t pathlen, homelen;
res = NULL;
if (path && *path++ == '~' && !isempty((home = getenv("HOME")))) {
while (*path == '/') path++;
pathlen = strlen(path);
homelen = strlen(home);
while (homelen && home[homelen - 1] == '/') homelen--;
if ((p = res = malloc(pathlen + 1 + homelen + 1))) {
p = mempcpy(p, home, homelen);
*p++ = '/';
memcpy(p, path, pathlen + 1);
}
}
return res;
}