/*
* make_relative_path - make a path relative to the actual binary location
*
* This function exists to support relocation of installation trees.
*
* ret_path is the output area (must be of size MAXPGPATH)
* target_path is the compiled-in path to the directory we want to find
* bin_path is the compiled-in path to the directory of executables
* my_exec_path is the actual location of my executable
*
* We determine the common prefix of target_path and bin_path, then compare
* the remainder of bin_path to the last directory component(s) of
* my_exec_path. If they match, build the result as the part of my_exec_path
* preceding the match, joined to the remainder of target_path. If no match,
* return target_path as-is.
*
* For example:
* target_path = '/usr/local/share/postgresql'
* bin_path = '/usr/local/bin'
* my_exec_path = '/opt/pgsql/bin/postmaster'
* Given these inputs, the common prefix is '/usr/local/', the tail of
* bin_path is 'bin' which does match the last directory component of
* my_exec_path, so we would return '/opt/pgsql/share/postgresql'
*/
static void
make_relative_path(char *ret_path, const char *target_path,
const char *bin_path, const char *my_exec_path)
{
int prefix_len;
int tail_start;
int tail_len;
int i;
/*
* Determine the common prefix --- note we require it to end on a
* directory separator, consider eg '/usr/lib' and '/usr/libexec'.
*/
prefix_len = 0;
for (i = 0; target_path[i] && bin_path[i]; i++)
{
if (IS_DIR_SEP(target_path[i]) && IS_DIR_SEP(bin_path[i]))
prefix_len = i + 1;
else if (target_path[i] != bin_path[i])
break;
}
if (prefix_len == 0)
goto no_match; /* no common prefix? */
tail_len = strlen(bin_path) - prefix_len;
/*
* Set up my_exec_path without the actual executable name, and
* canonicalize to simplify comparison to bin_path.
*/
strlcpy(ret_path, my_exec_path, MAXPGPATH);
trim_directory(ret_path); /* remove my executable name */
canonicalize_path(ret_path);
/*
* Tail match?
*/
tail_start = (int) strlen(ret_path) - tail_len;
if (tail_start > 0 &&
IS_DIR_SEP(ret_path[tail_start - 1]) &&
dir_strcmp(ret_path + tail_start, bin_path + prefix_len) == 0)
{
ret_path[tail_start] = '\0';
trim_trailing_separator(ret_path);
join_path_components(ret_path, ret_path, target_path + prefix_len);
canonicalize_path(ret_path);
return;
}
no_match:
strlcpy(ret_path, target_path, MAXPGPATH);
canonicalize_path(ret_path);
}
/*
* Clean up path by:
* o remove trailing slash
* o remove duplicate adjacent separators
* o remove trailing '.'
* o process trailing '..' ourselves
*/
void canonicalize_path(char *path)
{
char *p, *to_p;
bool was_sep = false;
/*
* Removing the trailing slash on a path means we never get ugly
* double trailing slashes.
*/
trim_trailing_separator(path);
/*
* Remove duplicate adjacent separators
*/
p = path;
to_p = p;
for (; *p; p++, to_p++)
{
/* Handle many adjacent slashes, like "/a///b" */
while (*p == '/' && was_sep)
p++;
if (to_p != p)
*to_p = *p;
was_sep = (*p == '/');
}
*to_p = '\0';
/*
* Remove any trailing uses of "." and process ".." ourselves
*/
for (;;)
{
int len = strlen(path);
if (len > 2 && strcmp(path + len - 2, "/.") == 0)
trim_directory(path);
else if (len > 3 && strcmp(path + len - 3, "/..") == 0)
{
trim_directory(path);
trim_directory(path);
/* remove directory above */
}
else
break;
}
}
/*
* Clean up path by:
* o make Win32 path use Unix slashes
* o remove trailing quote on Win32
* o remove trailing slash
* o remove duplicate adjacent separators
* o remove trailing '.'
* o process trailing '..' ourselves
*/
void
canonicalize_path(char *path)
{
char *p,
*to_p;
char *spath;
bool was_sep = false;
int pending_strips;
#ifdef WIN32
/*
* The Windows command processor will accept suitably quoted paths with
* forward slashes, but barfs badly with mixed forward and back slashes.
*/
for (p = path; *p; p++)
{
if (*p == '\\')
*p = '/';
}
/*
* In Win32, if you do: prog.exe "a b" "\c\d\" the system will pass \c\d"
* as argv[2], so trim off trailing quote.
*/
if (p > path && *(p - 1) == '"')
*(p - 1) = '/';
#endif
/*
* Removing the trailing slash on a path means we never get ugly double
* trailing slashes. Also, Win32 can't stat() a directory with a trailing
* slash. Don't remove a leading slash, though.
*/
trim_trailing_separator(path);
/*
* Remove duplicate adjacent separators
*/
p = path;
#ifdef WIN32
/* Don't remove leading double-slash on Win32 */
if (*p)
p++;
#endif
to_p = p;
for (; *p; p++, to_p++)
{
/* Handle many adjacent slashes, like "/a///b" */
while (*p == '/' && was_sep)
p++;
if (to_p != p)
*to_p = *p;
was_sep = (*p == '/');
}
*to_p = '\0';
/*
* Remove any trailing uses of "." and process ".." ourselves
*
* Note that "/../.." should reduce to just "/", while "../.." has to be
* kept as-is. In the latter case we put back mistakenly trimmed ".."
* components below. Also note that we want a Windows drive spec to be
* visible to trim_directory(), but it's not part of the logic that's
* looking at the name components; hence distinction between path and
* spath.
*/
spath = skip_drive(path);
pending_strips = 0;
for (;;)
{
int len = strlen(spath);
if (len >= 2 && strcmp(spath + len - 2, "/.") == 0)
trim_directory(path);
else if (strcmp(spath, ".") == 0)
{
/* Want to leave "." alone, but "./.." has to become ".." */
if (pending_strips > 0)
*spath = '\0';
break;
}
else if ((len >= 3 && strcmp(spath + len - 3, "/..") == 0) ||
strcmp(spath, "..") == 0)
{
trim_directory(path);
pending_strips++;
}
else if (pending_strips > 0 && *spath != '\0')
{
/* trim a regular directory name canceled by ".." */
trim_directory(path);
pending_strips--;
/* foo/.. should become ".", not empty */
if (*spath == '\0')
strcpy(spath, ".");
}
else
break;
}
if (pending_strips > 0)
{
/*
* We could only get here if path is now totally empty (other than a
* possible drive specifier on Windows). We have to put back one or
* more ".."'s that we took off.
*/
while (--pending_strips > 0)
strcat(path, "../");
strcat(path, "..");
}
}
/*
* Clean up path by:
* o make Win32 path use Unix slashes
* o remove trailing quote on Win32
* o remove trailing slash
* o remove duplicate adjacent separators
* o remove trailing '.'
* o process trailing '..' ourselves
*/
void
canonicalize_path(char *path)
{
char *p, *to_p;
bool was_sep = false;
#ifdef WIN32
/*
* The Windows command processor will accept suitably quoted paths
* with forward slashes, but barfs badly with mixed forward and back
* slashes.
*/
for (p = path; *p; p++)
{
if (*p == '\\')
*p = '/';
}
/*
* In Win32, if you do: prog.exe "a b" "\c\d\" the system will pass
* \c\d" as argv[2], so trim off trailing quote.
*/
if (p > path && *(p - 1) == '"')
*(p - 1) = '/';
#endif
/*
* Removing the trailing slash on a path means we never get ugly
* double trailing slashes. Also, Win32 can't stat() a directory
* with a trailing slash. Don't remove a leading slash, though.
*/
trim_trailing_separator(path);
/*
* Remove duplicate adjacent separators
*/
p = path;
#ifdef WIN32
/* Don't remove leading double-slash on Win32 */
if (*p)
p++;
#endif
to_p = p;
for (; *p; p++, to_p++)
{
/* Handle many adjacent slashes, like "/a///b" */
while (*p == '/' && was_sep)
p++;
if (to_p != p)
*to_p = *p;
was_sep = (*p == '/');
}
*to_p = '\0';
/*
* Remove any trailing uses of "." and process ".." ourselves
*/
for (;;)
{
int len = strlen(path);
if (len > 2 && strcmp(path + len - 2, "/.") == 0)
trim_directory(path);
else if (len > 3 && strcmp(path + len - 3, "/..") == 0)
{
trim_directory(path);
trim_directory(path); /* remove directory above */
}
else
break;
}
}
