1 | /* Duplicate a file descriptor to a given number, with flags. Hurd version. |
2 | Copyright (C) 1991-2022 Free Software Foundation, Inc. |
3 | |
4 | This file is part of the GNU C Library. |
5 | |
6 | The GNU C Library is free software; you can redistribute it and/or |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either |
9 | version 2.1 of the License, or (at your option) any later version. |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | Lesser General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; see the file COPYING.LIB. If |
18 | not, see <https://www.gnu.org/licenses/>. */ |
19 | |
20 | #include <errno.h> |
21 | #include <fcntl.h> |
22 | #include <unistd.h> |
23 | #include <hurd.h> |
24 | #include <hurd/fd.h> |
25 | |
26 | /* Duplicate FD to FD2, closing the old FD2 and making FD2 be |
27 | open on the same file as FD is, and setting FD2's flags according to FLAGS. |
28 | Return FD2 or -1. */ |
29 | int |
30 | __dup3 (int fd, int fd2, int flags) |
31 | { |
32 | struct hurd_fd *d; |
33 | |
34 | /* Both passing flags different from O_CLOEXEC and FD2 being the same as FD |
35 | are invalid. */ |
36 | if ((flags & ~O_CLOEXEC |
37 | || fd2 == fd) |
38 | /* ... with the exception in case that dup2 behavior is requested: if FD |
39 | is valid and FD2 is already the same then just return it. */ |
40 | && ! (flags == -1 |
41 | && fd2 == fd)) |
42 | return __hurd_fail (EINVAL); |
43 | |
44 | /* Extract the ports and flags from FD. */ |
45 | d = _hurd_fd_get (fd); |
46 | if (d == NULL) |
47 | return __hurd_fail (EBADF); |
48 | |
49 | HURD_CRITICAL_BEGIN; |
50 | |
51 | __spin_lock (&d->port.lock); |
52 | if (d->port.port == MACH_PORT_NULL) |
53 | { |
54 | __spin_unlock (&d->port.lock); |
55 | fd2 = __hurd_fail (EBADF); |
56 | } |
57 | else if (fd2 == fd) |
58 | __spin_unlock (&d->port.lock); |
59 | else |
60 | { |
61 | struct hurd_userlink ulink, ctty_ulink; |
62 | int d_flags = d->flags; |
63 | io_t ctty = _hurd_port_get (&d->ctty, &ctty_ulink); |
64 | io_t port = _hurd_port_locked_get (&d->port, &ulink); /* Unlocks D. */ |
65 | |
66 | if (fd2 < 0) |
67 | fd2 = __hurd_fail (EBADF); |
68 | else |
69 | { |
70 | /* Get a hold of the destination descriptor. */ |
71 | struct hurd_fd *d2; |
72 | |
73 | __mutex_lock (&_hurd_dtable_lock); |
74 | |
75 | if (fd2 >= _hurd_dtablesize) |
76 | { |
77 | /* The table is not large enough to hold the destination |
78 | descriptor. Enlarge it as necessary to allocate this |
79 | descriptor. */ |
80 | __mutex_unlock (&_hurd_dtable_lock); |
81 | d2 = _hurd_alloc_fd (NULL, fd2); |
82 | if (d2) |
83 | __spin_unlock (&d2->port.lock); |
84 | __mutex_lock (&_hurd_dtable_lock); |
85 | } |
86 | else |
87 | { |
88 | d2 = _hurd_dtable[fd2]; |
89 | if (d2 == NULL) |
90 | { |
91 | /* Must allocate a new one. We don't initialize the port |
92 | cells with this call so that if it fails (out of |
93 | memory), we will not have already added user |
94 | references for the ports, which we would then have to |
95 | deallocate. */ |
96 | d2 = _hurd_dtable[fd2] = _hurd_new_fd (MACH_PORT_NULL, |
97 | MACH_PORT_NULL); |
98 | } |
99 | } |
100 | __mutex_unlock (&_hurd_dtable_lock); |
101 | |
102 | if (d2 == NULL) |
103 | { |
104 | fd2 = -1; |
105 | if (errno == EINVAL) |
106 | errno = EBADF; /* POSIX.1-1990 6.2.1.2 ll 54-55. */ |
107 | } |
108 | else |
109 | { |
110 | /* Give the ports each a user ref for the new descriptor. */ |
111 | __mach_port_mod_refs (__mach_task_self (), port, |
112 | MACH_PORT_RIGHT_SEND, 1); |
113 | if (ctty != MACH_PORT_NULL) |
114 | __mach_port_mod_refs (__mach_task_self (), ctty, |
115 | MACH_PORT_RIGHT_SEND, 1); |
116 | |
117 | /* Install the ports and flags in the new descriptor slot. */ |
118 | __spin_lock (&d2->port.lock); |
119 | if (flags & O_CLOEXEC) |
120 | d2->flags = d_flags | FD_CLOEXEC; |
121 | else |
122 | /* dup clears FD_CLOEXEC. */ |
123 | d2->flags = d_flags & ~FD_CLOEXEC; |
124 | _hurd_port_set (&d2->ctty, ctty); |
125 | _hurd_port_locked_set (&d2->port, port); /* Unlocks D2. */ |
126 | } |
127 | } |
128 | |
129 | _hurd_port_free (&d->port, &ulink, port); |
130 | if (ctty != MACH_PORT_NULL) |
131 | _hurd_port_free (&d->ctty, &ctty_ulink, port); |
132 | } |
133 | |
134 | HURD_CRITICAL_END; |
135 | |
136 | return fd2; |
137 | } |
138 | libc_hidden_def (__dup3) |
139 | weak_alias (__dup3, dup3) |
140 | |