1 // descriptors.cc -- manage file descriptors for gold
3 // Copyright 2008, 2009 Free Software Foundation, Inc.
4 // Written by Ian Lance Taylor <iant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
30 #include "parameters.h"
31 #include "gold-threads.h"
32 #include "descriptors.h"
39 // The default for limit_ is meant to simply be large. It gets
40 // adjusted downward if we run out of file descriptors.
42 Descriptors::Descriptors()
43 : lock_(NULL
), open_descriptors_(), stack_top_(-1), current_(0),
46 this->open_descriptors_
.reserve(128);
52 Descriptors::open(int descriptor
, const char* name
, int flags
, int mode
)
54 // We don't initialize this until we are called, because we can't
55 // initialize a Lock until we have parsed the options to find out
56 // whether we are running with threads. We can be called before
57 // options are valid when reading a linker script.
58 if (this->lock_
== NULL
)
60 if (parameters
->options_valid())
61 this->lock_
= new Lock();
63 gold_assert(descriptor
< 0);
68 Hold_lock
hl(*this->lock_
);
70 gold_assert(static_cast<size_t>(descriptor
)
71 < this->open_descriptors_
.size());
72 Open_descriptor
* pod
= &this->open_descriptors_
[descriptor
];
74 || (pod
->name
!= NULL
&& strcmp(pod
->name
, name
) == 0))
76 gold_assert(!pod
->inuse
);
78 if (descriptor
== this->stack_top_
)
80 this->stack_top_
= pod
->stack_next
;
82 pod
->is_on_stack
= false;
90 int new_descriptor
= ::open(name
, flags
, mode
);
91 if (new_descriptor
< 0
95 if (descriptor
>= 0 && errno
== ENOENT
)
98 Hold_lock
hl(*this->lock_
);
100 gold_error(_("file %s was removed during the link"),
101 this->open_descriptors_
[descriptor
].name
);
107 return new_descriptor
;
110 if (new_descriptor
>= 0)
112 Hold_optional_lock
hl(this->lock_
);
114 if (static_cast<size_t>(new_descriptor
)
115 >= this->open_descriptors_
.size())
116 this->open_descriptors_
.resize(new_descriptor
+ 64);
118 Open_descriptor
* pod
= &this->open_descriptors_
[new_descriptor
];
120 pod
->stack_next
= -1;
122 pod
->is_write
= (flags
& O_ACCMODE
) != O_RDONLY
;
123 pod
->is_on_stack
= false;
126 if (this->current_
>= this->limit_
)
127 this->close_some_descriptor();
129 return new_descriptor
;
132 // We ran out of file descriptors.
134 Hold_optional_lock
hl(this->lock_
);
136 this->limit_
= this->current_
- 16;
137 if (this->limit_
< 8)
139 if (!this->close_some_descriptor())
140 gold_fatal(_("out of file descriptors and couldn't close any"));
145 // Release a descriptor.
148 Descriptors::release(int descriptor
, bool permanent
)
150 Hold_optional_lock
hl(this->lock_
);
152 gold_assert(descriptor
>= 0
153 && (static_cast<size_t>(descriptor
)
154 < this->open_descriptors_
.size()));
155 Open_descriptor
* pod
= &this->open_descriptors_
[descriptor
];
158 || (this->current_
> this->limit_
&& !pod
->is_write
))
160 if (::close(descriptor
) < 0)
161 gold_warning(_("while closing %s: %s"), pod
->name
, strerror(errno
));
168 if (!pod
->is_write
&& !pod
->is_on_stack
)
170 pod
->stack_next
= this->stack_top_
;
171 this->stack_top_
= descriptor
;
172 pod
->is_on_stack
= true;
177 // Close some descriptor. The lock is held when this is called. We
178 // close the descriptor on the top of the free stack. Note that this
179 // is the opposite of an LRU algorithm--we close the most recently
180 // used descriptor. That is because the linker tends to cycle through
181 // all the files; after we release a file, we are unlikely to need it
182 // again until we have looked at all the other files. Return true if
183 // we closed a descriptor.
186 Descriptors::close_some_descriptor()
189 int i
= this->stack_top_
;
192 gold_assert(static_cast<size_t>(i
) < this->open_descriptors_
.size());
193 Open_descriptor
* pod
= &this->open_descriptors_
[i
];
194 if (!pod
->inuse
&& !pod
->is_write
)
197 gold_warning(_("while closing %s: %s"), pod
->name
, strerror(errno
));
201 this->stack_top_
= pod
->stack_next
;
203 this->open_descriptors_
[last
].stack_next
= pod
->stack_next
;
204 pod
->stack_next
= -1;
205 pod
->is_on_stack
= false;
212 // We couldn't find any descriptors to close. This is weird but not
213 // necessarily an error.
217 // The single global variable which manages descriptors.
219 Descriptors descriptors
;
221 } // End namespace gold.
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