@ -46,8 +46,9 @@
static void make_relative_path ( char * ret_path , const char * target_path ,
const char * bin_path , const char * my_exec_path ) ;
static void trim_directory ( char * path ) ;
static char * trim_directory ( char * path ) ;
static void trim_trailing_separator ( char * path ) ;
static char * append_subdir_to_path ( char * path , char * subdir ) ;
/*
@ -222,13 +223,9 @@ join_path_components(char *ret_path,
strlcpy ( ret_path , head , MAXPGPATH ) ;
/*
* Remove any leading " . " in the tail component .
*
* Note : we used to try to remove " .. " as well , but that ' s tricky to get
* right ; now we just leave it to be done by canonicalize_path ( ) later .
* We used to try to simplify some cases involving " . " and " .. " , but now
* we just leave that to be done by canonicalize_path ( ) later .
*/
while ( tail [ 0 ] = = ' . ' & & IS_DIR_SEP ( tail [ 1 ] ) )
tail + = 2 ;
if ( * tail )
{
@ -241,14 +238,27 @@ join_path_components(char *ret_path,
}
/* State-machine states for canonicalize_path */
typedef enum
{
ABSOLUTE_PATH_INIT , /* Just past the leading '/' (and Windows
* drive name if any ) of an absolute path */
ABSOLUTE_WITH_N_DEPTH , /* We collected 'pathdepth' directories in an
* absolute path */
RELATIVE_PATH_INIT , /* At start of a relative path */
RELATIVE_WITH_N_DEPTH , /* We collected 'pathdepth' directories in a
* relative path */
RELATIVE_WITH_PARENT_REF /* Relative path containing only double-dots */
} canonicalize_state ;
/*
* 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
* o remove duplicate ( adjacent ) separators
* o remove ' . ' ( unless path reduces to only ' . ' )
* o process ' . . ' ourselves , removing it if possible
*/
void
canonicalize_path ( char * path )
@ -256,8 +266,11 @@ canonicalize_path(char *path)
char * p ,
* to_p ;
char * spath ;
char * parsed ;
char * unparse ;
bool was_sep = false ;
int pending_strips ;
canonicalize_state state ;
int pathdepth = 0 ; /* counts collected regular directory names */
# ifdef WIN32
@ -308,60 +321,173 @@ canonicalize_path(char *path)
* to_p = ' \0 ' ;
/*
* Remove any trailing uses of " . " and process " .. " ourselves
* Remove any 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 .
* kept as - is . 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 .
*
* This loop overwrites the path in - place . This is safe since we ' ll never
* make the path longer . " unparse " points to where we are reading the
* path , " parse " to where we are writing .
*/
spath = skip_drive ( path ) ;
pending_strips = 0 ;
for ( ; ; )
if ( * spath = = ' \0 ' )
return ; /* empty path is returned as-is */
if ( * spath = = ' / ' )
{
int len = strlen ( spath ) ;
state = ABSOLUTE_PATH_INIT ;
/* Skip the leading slash for absolute path */
parsed = unparse = ( spath + 1 ) ;
}
else
{
state = RELATIVE_PATH_INIT ;
parsed = unparse = spath ;
}
if ( len > = 2 & & strcmp ( spath + len - 2 , " /. " ) = = 0 )
trim_directory ( path ) ;
else if ( strcmp ( spath , " . " ) = = 0 )
while ( * unparse ! = ' \0 ' )
{
char * unparse_next ;
bool is_double_dot ;
/* Split off this dir name, and set unparse_next to the next one */
unparse_next = unparse ;
while ( * unparse_next & & * unparse_next ! = ' / ' )
unparse_next + + ;
if ( * unparse_next ! = ' \0 ' )
* unparse_next + + = ' \0 ' ;
/* Identify type of this dir name */
if ( strcmp ( unparse , " . " ) = = 0 )
{
/* Want to leave "." alone, but "./.." has to become ".." */
if ( pending_strips > 0 )
* spath = ' \0 ' ;
break ;
/* We can ignore "." components in all cases */
unparse = unparse_next ;
continue ;
}
else if ( ( len > = 3 & & strcmp ( spath + len - 3 , " /.. " ) = = 0 ) | |
strcmp ( spath , " .. " ) = = 0 )
if ( strcmp ( unparse , " .. " ) = = 0 )
is_double_dot = true ;
else
{
trim_directory ( path ) ;
pending_strips + + ;
/* adjacent separators were eliminated above */
Assert ( * unparse ! = ' \0 ' ) ;
is_double_dot = false ;
}
else if ( pending_strips > 0 & & * spath ! = ' \0 ' )
switch ( state )
{
/* trim a regular directory name canceled by ".." */
trim_directory ( path ) ;
pending_strips - - ;
/* foo/.. should become ".", not empty */
if ( * spath = = ' \0 ' )
strcpy ( spath , " . " ) ;
case ABSOLUTE_PATH_INIT :
/* We can ignore ".." immediately after / */
if ( ! is_double_dot )
{
/* Append first dir name (we already have leading slash) */
parsed = append_subdir_to_path ( parsed , unparse ) ;
state = ABSOLUTE_WITH_N_DEPTH ;
pathdepth + + ;
}
break ;
case ABSOLUTE_WITH_N_DEPTH :
if ( is_double_dot )
{
/* Remove last parsed dir */
/* (trim_directory won't remove the leading slash) */
* parsed = ' \0 ' ;
parsed = trim_directory ( path ) ;
if ( - - pathdepth = = 0 )
state = ABSOLUTE_PATH_INIT ;
}
else
{
/* Append normal dir */
* parsed + + = ' / ' ;
parsed = append_subdir_to_path ( parsed , unparse ) ;
pathdepth + + ;
}
break ;
case RELATIVE_PATH_INIT :
if ( is_double_dot )
{
/* Append irreducible double-dot (..) */
parsed = append_subdir_to_path ( parsed , unparse ) ;
state = RELATIVE_WITH_PARENT_REF ;
}
else
{
/* Append normal dir */
parsed = append_subdir_to_path ( parsed , unparse ) ;
state = RELATIVE_WITH_N_DEPTH ;
pathdepth + + ;
}
break ;
case RELATIVE_WITH_N_DEPTH :
if ( is_double_dot )
{
/* Remove last parsed dir */
* parsed = ' \0 ' ;
parsed = trim_directory ( path ) ;
if ( - - pathdepth = = 0 )
{
/*
* If the output path is now empty , we ' re back to the
* INIT state . However , we could have processed a
* path like " ../dir/.. " and now be down to " .. " , in
* which case enter the correct state for that .
*/
if ( parsed = = spath )
state = RELATIVE_PATH_INIT ;
else
state = RELATIVE_WITH_PARENT_REF ;
}
}
else
{
/* Append normal dir */
* parsed + + = ' / ' ;
parsed = append_subdir_to_path ( parsed , unparse ) ;
pathdepth + + ;
}
break ;
case RELATIVE_WITH_PARENT_REF :
if ( is_double_dot )
{
/* Append next irreducible double-dot (..) */
* parsed + + = ' / ' ;
parsed = append_subdir_to_path ( parsed , unparse ) ;
}
else
{
/* Append normal dir */
* parsed + + = ' / ' ;
parsed = append_subdir_to_path ( parsed , unparse ) ;
/*
* We can now start counting normal dirs . But if later
* double - dots make us remove this dir again , we ' d better
* revert to RELATIVE_WITH_PARENT_REF not INIT state .
*/
state = RELATIVE_WITH_N_DEPTH ;
pathdepth = 1 ;
}
break ;
}
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 , " .. " ) ;
unparse = unparse_next ;
}
/*
* If our output path is empty at this point , insert " . " . We don ' t want
* to do this any earlier because it ' d result in an extra dot in corner
* cases such as " ../dir/.. " . Since we rejected the wholly - empty - path
* case above , there is certainly room .
*/
if ( parsed = = spath )
* parsed + + = ' . ' ;
/* And finally, ensure the output path is nul-terminated. */
* parsed = ' \0 ' ;
}
/*
@ -865,8 +991,11 @@ get_parent_directory(char *path)
* Trim trailing directory from path , that is , remove any trailing slashes ,
* the last pathname component , and the slash just ahead of it - - - but never
* remove a leading slash .
*
* For the convenience of canonicalize_path , the path ' s new end location
* is returned .
*/
static void
static char *
trim_directory ( char * path )
{
char * p ;
@ -874,7 +1003,7 @@ trim_directory(char *path)
path = skip_drive ( path ) ;
if ( path [ 0 ] = = ' \0 ' )
return ;
return path ;
/* back up over trailing slash(es) */
for ( p = path + strlen ( path ) - 1 ; IS_DIR_SEP ( * p ) & & p > path ; p - - )
@ -889,6 +1018,7 @@ trim_directory(char *path)
if ( p = = path & & IS_DIR_SEP ( * p ) )
p + + ;
* p = ' \0 ' ;
return p ;
}
@ -908,3 +1038,25 @@ trim_trailing_separator(char *path)
for ( p - - ; p > path & & IS_DIR_SEP ( * p ) ; p - - )
* p = ' \0 ' ;
}
/*
* append_subdir_to_path
*
* Append the currently - considered subdirectory name to the output
* path in canonicalize_path . Return the new end location of the
* output path .
*
* Since canonicalize_path updates the path in - place , we must use
* memmove not memcpy , and we don ' t yet terminate the path with ' \0 ' .
*/
static char *
append_subdir_to_path ( char * path , char * subdir )
{
size_t len = strlen ( subdir ) ;
/* No need to copy data if path and subdir are the same. */
if ( path ! = subdir )
memmove ( path , subdir , len ) ;
return path + len ;
}
Tom Lane
4 years ago