On 9/24/2019 2:27 PM, Eric Blake wrote: > On 9/24/19 12:55 PM, Ken Brown wrote: >> If the last component of the directory name is a symlink followed by a >> slash, rmdir should fail, even if the symlink resolves to an existing >> empty directory. >> >> mkdir was similarly fixed in 2009 in commit >> 52dba6a5c45e8d8ba1e237a15213311dc11d91fb. Modify a comment to clarify >> the purpose of that commit. >> >> Addresses https://cygwin.com/ml/cygwin/2019-09/msg00221.html. >> --- >> winsup/cygwin/dir.cc | 27 +++++++++++++++++++++++---- >> 1 file changed, 23 insertions(+), 4 deletions(-) >> >> diff --git a/winsup/cygwin/dir.cc b/winsup/cygwin/dir.cc >> index b757851d5..0e0535891 100644 >> --- a/winsup/cygwin/dir.cc >> +++ b/winsup/cygwin/dir.cc >> @@ -305,15 +305,14 @@ mkdir (const char *dir, mode_t mode) >> >> __try >> { >> - /* POSIX says mkdir("symlink-to-missing/") should create the >> - directory "missing", but Linux rejects it with EEXIST. Copy >> - Linux behavior for now. */ >> - >> if (!*dir) >> { >> set_errno (ENOENT); >> __leave; >> } >> + /* Following Linux, do not resolve the last component of DIR if >> + it is a symlink, even if DIR has a trailing slash. Achieve >> + this by stripping trailing slashes or backslashes. */ > > Maybe even "Following Linux, and intentionally ignoring POSIX, do not..." > >> + >> + /* Following Linux, do not resolve the last component of DIR if >> + it is a symlink, even if DIR has a trailing slash. Achieve >> + this by stripping trailing slashes or backslashes. */ >> + if (isdirsep (dir[strlen (dir) - 1])) >> + { >> + /* This converts // to /, but since both give ENOTEMPTY, >> + we're okay. */ >> + char *buf; >> + char *p = stpcpy (buf = tp.c_get (), dir) - 1; >> + dir = buf; >> + while (p > dir && isdirsep (*p)) >> + *p-- = '\0'; >> + } >> if (!(fh = build_fh_name (dir, PC_SYM_NOFOLLOW))) >> __leave; /* errno already set */; >> > > Looks okay to me.
Thanks. Does the "intentionally ignoring POSIX" part apply to rmdir also? I didn't find it easy to decipher POSIX. Even for mkdir, POSIX says, "If path names a symbolic link, mkdir() shall fail and set errno to [EEXIST]." See https://pubs.opengroup.org/onlinepubs/9699919799/functions/mkdir.html#tag_16_325. But I'm not clear on how POSIX decides whether "path names a symbolic link" in the case where the last component is a symlink followed by a slash. Ken
