/**
* mds — A micro-display server
* Copyright © 2014, 2015, 2016, 2017 Mattias Andrée (m@maandree.se)
*
* 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 3 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 "paths.h"
#include <libmdsserver/macros.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/**
* Get the current working directory
*
* @return The current working directory
*/
char *
curpath(void)
{
static size_t cwd_size = 4096;
char *cwd = NULL;
char *old = NULL;
int saved_errno;
/* glibc offers ways to do this in just one function call,
* but we will not assume that glibc is used here. */
for (;;) {
fail_if (xxrealloc(old, cwd, cwd_size + 1, char));
if (getcwd(cwd, cwd_size))
break;
else
fail_if (errno != ERANGE);
cwd_size <<= 1;
}
return cwd;
fail:
saved_errno = errno;
free(old);
free(cwd);
errno = saved_errno;
return NULL;
}
/**
* Get the absolute path of a file
*
* @param path The filename of the file
* @return The file's absolute path, `NULL` on error
*/
char *
abspath(const char *path)
{
char *cwd = NULL;
char *buf = NULL;
int saved_errno, slash = 1;
size_t size, p;
if (*path == '/') {
fail_if (xstrdup(buf, path));
return buf;
}
fail_if (!(cwd = curpath()));
size = (p = strlen(cwd)) + strlen(path) + 2;
fail_if (xmalloc(buf, size + 1, char));
memcpy(buf, cwd, (p + 1) * sizeof(char));
if (buf[p - 1] != '/')
buf[p++] = '/';
while (*path) {
if (slash && path[0] == '/') {
path += 1;
} else if (slash && path[0] == '.' && path[1] == '/') {
path += 2;
} else if (slash && path[0] == '.' && path[1] == '.' && path[2] == '/') {
path += 3;
p--;
while (p && buf[--p] != '/');
p++;
} else {
buf[p++] = *path;
slash = *path++ == '/';
}
}
buf[p] = '\0';
free(cwd);
return buf;
fail:
saved_errno = errno;
free(cwd);
errno = saved_errno;
return NULL;
}
/**
* Get a relative path of a file
*
* @param path The filename of the file
* @param base The pathname of the base directory,
* `NULL` for the current working directroy
* @return The file's relative path, `NULL` on error
*/
char *
relpath(const char *path, const char *base)
{
char *abs = abspath(path);
char *absbase = NULL;
char *buf = NULL;
char *old = NULL;
int saved_errno;
size_t p, slash = 1, back = 0;
fail_if (!abs);
absbase = base ? abspath(base) : curpath();
fail_if (!absbase);
if (absbase[strlen(absbase) - 1] != '/')
/* Both `abspath` and `curpath` (and `relpath`) allocates one extra slot. */
absbase[strlen(absbase) + 1] = '\0', absbase[strlen(absbase)] = '/';
for (p = 1; abs[p] && absbase[p] && abs[p] == absbase[p]; p++)
if (abs[p] == '/')
slash = p + 1;
for (p = slash; absbase[p]; p++)
if (absbase[p] == '/')
back++;
fail_if (xmalloc(buf, back * 3 + strlen(abs + slash) + 2, char));
for (p = 0; back--;)
buf[p++] = '.', buf[p++] = '.', buf[p++] = '/';
memcpy(buf + p, abs + slash, (strlen(abs + slash) + 1) * sizeof(char));
free(abs);
free(absbase);
return buf;
fail:
saved_errno = errno;
free(abs);
free(absbase);
free(old);
errno = saved_errno;
return NULL;
}
