xbps/lib/util_path.c

292 lines
7.1 KiB
C

/*-
* Copyright (c) 2015-2019 Juan Romero Pardines.
* Copyright (c) 2020 Duncan Overbruck <mail@duncano.de>.
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
/*-
* xbps_path_clean is based on the go filepath.Clean function:
* - https://github.com/golang/go/blob/cfe2ab42/src/path/filepath/path.go#L88
*
* Copyright (c) 2009 The Go Authors. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * 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.
* * Neither the name of Google Inc. 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 COPYRIGHT HOLDERS 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 COPYRIGHT
* OWNER 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 <string.h>
#include <stdlib.h>
#include <errno.h>
#include "xbps_api_impl.h"
ssize_t
xbps_path_clean(char *dst)
{
char buf[PATH_MAX];
const char *p = buf;
const char *dotdot = dst;
char *d = dst;
bool rooted = *dst == '/';
if (xbps_strlcpy(buf, dst, sizeof buf) >= sizeof buf)
return -1;
if (rooted) {
*d++ = '/';
p++;
dotdot++;
}
for (; *p;) {
switch (*p) {
/* empty path element */
case '/': p++; break;
case '.':
if (p[1] == '\0' || p[1] == '/') {
/* . element */
p++;
continue;
} else if (p[1] == '.' && (p[2] == '\0' || p[2] == '/')) {
p += 2;
/* .. element */
if (d > dotdot) {
/* can backtrack */
d--;
for (; d > dotdot && *d != '/'; d--)
;
} else if (!rooted) {
/* cannot backtrack, but not rooted,
* append .. element. */
if (d > dst)
*d++ = '/';
*d++ = '.';
*d++ = '.';
dotdot = d;
}
continue;
}
/* normal path element starting with . */
/* FALLTHROUGH */
default:
if (d > dst+(rooted ? 1 : 0))
*d++ = '/';
for (; *p && *p != '/'; p++)
*d++ = *p;
}
}
/* Turn empty string into "." */
if (d == dst)
*d++ = '.';
*d = '\0';
return (d-dst);
}
ssize_t
xbps_path_rel(char *dst, size_t dstlen, const char *from, const char *to)
{
char frombuf[PATH_MAX], tobuf[PATH_MAX];
const char *fromp = frombuf, *top = tobuf, *suffix = tobuf;
size_t len = 0;
int up = -1;
*dst = '\0';
if (xbps_strlcpy(frombuf, from, sizeof frombuf) >= sizeof frombuf ||
xbps_strlcpy(tobuf, to, sizeof tobuf) >= sizeof tobuf)
return -1;
if (xbps_path_clean(frombuf) == -1 || xbps_path_clean(tobuf) == -1)
return -1;
for (; *fromp == *top && *to; fromp++, top++)
if (*top == '/')
suffix = top;
for (up = -1, fromp--; fromp && *fromp; fromp = strchr(fromp+1, '/'), up++)
;
while (up--) {
for (const char *x = "../"; *x; x++) {
if (len+1 < dstlen)
dst[len] = *x;
len++;
}
}
if (*suffix != '\0') {
for (suffix += 1; *suffix; suffix++) {
if (len+1 < dstlen)
dst[len] = *suffix;
len++;
}
}
dst[len < dstlen ? len : dstlen - 1] = '\0';
return len;
}
static ssize_t
xbps_path_vjoin(char *dst, size_t dstlen, va_list ap)
{
size_t len = 0;
const char *val;
*dst = '\0';
if ((val = va_arg(ap, const char *)) == NULL)
return 0;
for (;;) {
size_t n;
if ((n = xbps_strlcat(dst+len, val, dstlen-len)) >= dstlen-len)
goto err;
len += n;
if ((val = va_arg(ap, const char *)) == NULL)
break;
if (len > 0 && dst[len-1] != '/') {
if (len+1 > dstlen)
goto err;
dst[len] = '/';
dst[len+1] = '\0';
len++;
}
if (len > 0 && *val == '/')
val++;
}
return (ssize_t)len < 0 ? -1 : (ssize_t)len;
err:
errno = ENOBUFS;
return -1;
}
ssize_t
xbps_path_join(char *dst, size_t dstlen, ...)
{
ssize_t len;
va_list ap;
va_start(ap, dstlen);
len = xbps_path_vjoin(dst, dstlen, ap);
va_end(ap);
return len;
}
ssize_t
xbps_path_append(char *dst, size_t dstlen, const char *suffix)
{
size_t len = strlen(dst);
if (*suffix == '\0')
goto out;
if (*dst == '\0') {
if ((len = xbps_strlcpy(dst, suffix, dstlen)) >= dstlen)
goto err;
goto out;
}
if (dst[len-1] != '/' && len+1 < dstlen) {
dst[len] = '/';
dst[len+1] = '\0';
}
if (*suffix == '/')
suffix++;
if ((len = xbps_strlcat(dst, suffix, dstlen)) >= dstlen)
goto err;
out:
return (ssize_t)len < 0 ? -1 : (ssize_t)len;
err:
errno = ENOBUFS;
return -1;
}
ssize_t
xbps_path_prepend(char *dst, size_t dstlen, const char *prefix)
{
size_t len, prelen;
char *p = dst;
len = strlen(dst);
if (*prefix == '\0')
goto out;
if (*dst == '\0') {
if ((len = xbps_strlcpy(dst, prefix, dstlen)) >= dstlen)
goto err;
goto out;
}
prelen = strlen(prefix);
if (prefix[prelen-1] == '/')
prelen--;
if (*dst == '/') {
len--;
p++;
}
/* prefix + '/' + dst + '\0' */
if (len+prelen+2 > dstlen)
goto err;
memmove(dst+prelen+1, p, len);
len += prelen+1;
dst[prelen] = '/';
memcpy(dst, prefix, prelen);
dst[len] = '\0';
out:
return (ssize_t)len < 0 ? -1 : (ssize_t)len;
err:
errno = ENOBUFS;
return -1;
}