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Cygwin: Move O_TMPFILE to bin and allow linkat by handle

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Along the same lines as the previous patch: By reopening an
O_TMPFILE by handle, we can now move the file to the bin at
open time and thus free'ing up the parent dir and *still*
open the file as /proc/PID/fd/DESCRIPTOR by linkat(2).
This commit is contained in:
Corinna Vinschen
2019-01-05 22:15:58 +01:00
parent a1a750325e
commit 7dbe307e38
3 changed files with 90 additions and 1 deletions
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82
winsup/cygwin/fhandler_process.cc
View File

@ -399,6 +399,88 @@ err_out:
return fh;
}
int
fhandler_process::link (const char *newpath)
{
const char *path;
int fd;
char *e;
path = get_name () + proc_len + 1;
pid = atoi (path);
while (*path != 0 && !isdirsep (*path))
path++;
if (*path == 0)
goto err_out;
virt_tab_t *entry;
entry = virt_tab_search (path + 1, true, process_tab, PROCESS_LINK_COUNT);
if (!entry || entry->fhandler != FH_PROCESSFD)
goto err_out;
if (path[3] != '/' || path[4] == '\0')
goto err_out;
fd = strtoul (path + 4, &e, 10);
if (fd < 0 || e == path + 4 || (*e != '/' && *e != '\0'))
goto err_out;
if (pid == myself->pid)
{
cygheap_fdget cfd (fd);
if (cfd < 0)
goto err_out;
return cfd->link (newpath);
}
else
{
HANDLE proc;
size_t size;
void *buf;
path_conv pc;
HANDLE hdl;
fhandler_base *fh = NULL;
int ret = -1;
pinfo p (pid);
if (!p)
{
set_errno (ENOENT);
return -1;
}
if (!(proc = OpenProcess (PROCESS_DUP_HANDLE, false, p->dwProcessId)))
goto err_out;
buf = p->file_pathconv (fd, size);
if (size == 0)
{
set_errno (EPERM);
goto err_out_close_proc;
}
hdl = pc.deserialize (buf);
if (!DuplicateHandle (proc, hdl, GetCurrentProcess (), &hdl,
0, FALSE, DUPLICATE_SAME_ACCESS))
{
__seterrno ();
goto err_out_close_proc;
}
fh = build_fh_pc (pc);
if (!fh)
goto err_out_close_dup;
fh->set_io_handle (hdl);
ret = fh->link (newpath);
delete fh;
err_out_close_dup:
CloseHandle (hdl);
err_out_close_proc:
CloseHandle (proc);
return ret;
}
err_out:
set_errno (EPERM);
return -1;
}
struct process_fd_t {
const char *path;
_pinfo *p;