1 | /* Copyright (C) 1994-2022 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either |
7 | version 2.1 of the License, or (at your option) any later version. |
8 | |
9 | The GNU C Library is distributed in the hope that it will be useful, |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include <hurd.h> |
19 | #include <hurd/fd.h> |
20 | #include <hurd/resource.h> |
21 | #include <stdlib.h> |
22 | #include "hurdmalloc.h" /* XXX */ |
23 | |
24 | /* Allocate a new file descriptor and return it, locked. The new |
25 | descriptor number will be no less than FIRST_FD. If the table is full, |
26 | set errno to EMFILE and return NULL. If FIRST_FD is negative or bigger |
27 | than the size of the table, set errno to EINVAL and return NULL. */ |
28 | |
29 | struct hurd_fd * |
30 | _hurd_alloc_fd (int *fd, int first_fd) |
31 | { |
32 | int i; |
33 | void *crit; |
34 | long int rlimit; |
35 | |
36 | if (first_fd < 0) |
37 | { |
38 | errno = EINVAL; |
39 | return NULL; |
40 | } |
41 | |
42 | crit = _hurd_critical_section_lock (); |
43 | |
44 | __mutex_lock (&_hurd_dtable_lock); |
45 | |
46 | search: |
47 | for (i = first_fd; i < _hurd_dtablesize; ++i) |
48 | { |
49 | struct hurd_fd *d = _hurd_dtable[i]; |
50 | if (d == NULL) |
51 | { |
52 | /* Allocate a new descriptor structure for this slot, |
53 | initializing its port cells to nil. The test below will catch |
54 | and return this descriptor cell after locking it. */ |
55 | d = _hurd_new_fd (MACH_PORT_NULL, MACH_PORT_NULL); |
56 | if (d == NULL) |
57 | { |
58 | __mutex_unlock (&_hurd_dtable_lock); |
59 | _hurd_critical_section_unlock (crit); |
60 | return NULL; |
61 | } |
62 | _hurd_dtable[i] = d; |
63 | } |
64 | |
65 | __spin_lock (&d->port.lock); |
66 | if (d->port.port == MACH_PORT_NULL) |
67 | { |
68 | __mutex_unlock (&_hurd_dtable_lock); |
69 | _hurd_critical_section_unlock (crit); |
70 | if (fd != NULL) |
71 | *fd = i; |
72 | return d; |
73 | } |
74 | else |
75 | __spin_unlock (&d->port.lock); |
76 | } |
77 | |
78 | __mutex_lock (&_hurd_rlimit_lock); |
79 | rlimit = _hurd_rlimits[RLIMIT_OFILE].rlim_cur; |
80 | __mutex_unlock (&_hurd_rlimit_lock); |
81 | |
82 | if (first_fd < rlimit) |
83 | { |
84 | /* The descriptor table is full. Check if we have reached the |
85 | resource limit, or only the allocated size. */ |
86 | if (_hurd_dtablesize < rlimit) |
87 | { |
88 | /* Enlarge the table. */ |
89 | int save = errno; |
90 | struct hurd_fd **new; |
91 | /* Try to double the table size, but don't exceed the limit, |
92 | and make sure it exceeds FIRST_FD. */ |
93 | int size = _hurd_dtablesize * 2; |
94 | if (size > rlimit) |
95 | size = rlimit; |
96 | else if (size <= first_fd) |
97 | size = first_fd + 1; |
98 | |
99 | if (size * sizeof (*_hurd_dtable) < size) |
100 | { |
101 | /* Integer overflow! */ |
102 | errno = ENOMEM; |
103 | goto out; |
104 | } |
105 | |
106 | /* If we fail to allocate that, decrement the desired size |
107 | until we succeed in allocating it. */ |
108 | do |
109 | new = realloc (_hurd_dtable, size * sizeof (*_hurd_dtable)); |
110 | while (new == NULL && size-- > first_fd); |
111 | |
112 | if (new != NULL) |
113 | { |
114 | /* We managed to allocate a new table. Now install it. */ |
115 | errno = save; |
116 | if (first_fd < _hurd_dtablesize) |
117 | first_fd = _hurd_dtablesize; |
118 | /* Initialize the new slots. */ |
119 | for (i = _hurd_dtablesize; i < size; ++i) |
120 | new[i] = NULL; |
121 | _hurd_dtablesize = size; |
122 | _hurd_dtable = new; |
123 | /* Go back to the loop to initialize the first new slot. */ |
124 | goto search; |
125 | } |
126 | else |
127 | errno = ENOMEM; |
128 | } |
129 | else |
130 | errno = EMFILE; |
131 | } |
132 | else |
133 | errno = EINVAL; /* Bogus FIRST_FD value. */ |
134 | |
135 | out: |
136 | __mutex_unlock (&_hurd_dtable_lock); |
137 | _hurd_critical_section_unlock (crit); |
138 | |
139 | return NULL; |
140 | } |
141 | |