grafX2/src/realpath.c

141 lines
4.3 KiB
C

/* vim:expandtab:ts=2 sw=2:
*/
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#ifndef _MSC_VER
#include <unistd.h>
#endif
#if !defined(WIN32)
#include <limits.h>
#endif
#if defined(__AROS__) || defined(__BEOS__) || defined(__MORPHOS__) || defined(__GP2X__) || defined(__WIZ__) || defined(__CAANOO__) || defined(__amigaos__) || defined(__SWITCH__)
// These platforms don't have realpath().
// We use the following implementation, found in:
// http://amiga.sourceforge.net/amigadevhelp/FUNCTIONS/GeekGadgets/realpath/ex02_realpath.c
//
// When tested on Debian, this piece of code doesn't resolve
// symbolic link in the filename itself, only on the directories in
// the path. So this implementation is limited, it's really better to
// use realpath() if your platform has it.
#if !defined(PATH_MAX)
// This is a random default value ...
#define PATH_MAX 4096
#endif
static char *sep(char *path)
{
char *tmp, c;
tmp = strrchr(path, '/');
if(tmp) {
c = tmp[1];
tmp[1] = 0;
if (chdir(path)) {
return NULL;
}
tmp[1] = c;
return tmp + 1;
}
return path;
}
// Find the real path of _path by chdir to it and then getcwd.
// If resolved_path is null, it is allocated.
char *Realpath(const char *_path, char *resolved_path)
{
#if defined(__AROS__)
int fd = open("", O_RDONLY); // GrafX2 is compiled without Unix support
#else
int fd = open(".", O_RDONLY);
#endif
int l;
char current_dir_path[PATH_MAX];
char path[PATH_MAX], lnk[PATH_MAX], *tmp = (char *)"";
if (fd < 0) {
return NULL;
}
getcwd(current_dir_path,PATH_MAX);
strncpy(path, _path, PATH_MAX);
if (chdir(path)) {
if (errno == ENOTDIR) {
#if defined(WIN32) || defined(__MORPHOS__) || defined(__amigaos__) || defined(__SWITCH__)
// No symbolic links and no readlink()
l = -1;
#else
l = readlink(path, lnk, PATH_MAX);
#endif
if (!(tmp = sep(path))) {
resolved_path = NULL;
goto abort;
}
if (l < 0) {
if (errno != EINVAL) {
resolved_path = NULL;
goto abort;
}
} else {
lnk[l] = 0;
if (!(tmp = sep(lnk))) {
resolved_path = NULL;
goto abort;
}
}
} else {
resolved_path = NULL;
goto abort;
}
}
if(resolved_path==NULL) // if we called realpath with null as a 2nd arg
resolved_path = (char*) malloc( PATH_MAX );
if (!getcwd(resolved_path, PATH_MAX)) {
resolved_path = NULL;
goto abort;
}
if(strcmp(resolved_path, "/") && *tmp) {
strcat(resolved_path, "/");
}
strcat(resolved_path, tmp);
abort:
chdir(current_dir_path);
close(fd);
return resolved_path;
}
#elif defined(__WIN32__) || defined(WIN32)
// Mingw has a working equivalent. It only has reversed arguments.
char *Realpath(const char *_path, char *resolved_path)
{
return _fullpath(resolved_path,_path,260);
}
#else
// Use the stdlib function.
char *Realpath(const char *_path, char *resolved_path)
{
/// POSIX 2004 states :
/// If resolved_name is a null pointer, the behavior of realpath()
/// is implementation-defined.
///
/// but POSIX 2008 :
/// If resolved_name is a null pointer, the generated pathname shall
/// be stored as a null-terminated string in a buffer allocated as if
/// by a call to malloc().
///
/// So we assume all platforms now support passing NULL.
/// If you find a platform where this is not the case,
/// please add a new implementation with ifdef's.
return realpath(_path, resolved_path);
}
#endif