JehanneOS/newlib
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Cygwin: implement /proc/PID/fd/DESCRIPTOR reopening by handle

Browse Source 
Allows expressions along the lines of `cat /proc/self/fd/0 <<EOF'.
The problem here is that the temporary file used for the here script
has already been deleted by the shell.  Opening by filename, as
implemented so far, doesn't work because the file has been moved
to the bin.

Allow reopening files by handle the same way from another process
as long as we have sufficient permissions on the foreign process.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
This commit is contained in:
Corinna Vinschen
2019-01-05 22:13:42 +01:00
parent c76468182b
commit 732613f30a
6 changed files with 108 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
winsup/cygwin/syscalls.cc
View File

@@ -1368,6 +1368,7 @@ open (const char *unix_path, int flags, ...)
va_list ap;
mode_t mode = 0;
fhandler_base *fh = NULL;
fhandler_base *fh_file = NULL;
pthread_testcancel ();
@@ -1394,8 +1395,9 @@ open (const char *unix_path, int flags, ...)
with a change in behavior that implements linux functionality:
opening a tty should not automatically cause it to become the
controlling tty for the process. */
int opt = PC_OPEN | ((flags & (O_NOFOLLOW | O_EXCL))
? PC_SYM_NOFOLLOW : PC_SYM_FOLLOW);
int opt = PC_OPEN | PC_SYM_NOFOLLOW_PROCFD;
opt |= (flags & (O_NOFOLLOW | O_EXCL)) ? PC_SYM_NOFOLLOW
: PC_SYM_FOLLOW;
if (!(flags & O_NOCTTY) && fd > 2 && myself->ctty != -2)
{
flags |= O_NOCTTY;
@@ -1438,7 +1440,6 @@ open (const char *unix_path, int flags, ...)
followed by an 8 byte unique hex number, followed by an 8 byte
random hex number. */
int64_t rnd;
fhandler_base *fh_file;
char *new_path;
new_path = (char *) malloc (strlen (fh->get_name ())
@@ -1464,8 +1465,17 @@ open (const char *unix_path, int flags, ...)
fh = fh_file;
}
if ((fh->is_fs_special () && fh->device_access_denied (flags))
|| !fh->open_with_arch (flags, mode & 07777))
if (fh->dev () == FH_PROCESSFD)
{
/* Reopen file by descriptor */
fh_file = fh->fd_reopen (flags);
if (!fh_file)
__leave;
delete fh;
fh = fh_file;
}
else if ((fh->is_fs_special () && fh->device_access_denied (flags))
|| !fh->open_with_arch (flags, mode & 07777))
__leave; /* errno already set */
fd = fh;
if (fd <= 2)