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author | Ton Voon <tonvoon@users.sourceforge.net> | 2007-01-24 22:47:25 (GMT) |
---|---|---|
committer | Ton Voon <tonvoon@users.sourceforge.net> | 2007-01-24 22:47:25 (GMT) |
commit | fe856aa957978504137c1d425815d4ed8a22be40 (patch) | |
tree | a5bb46ce0e64b2056f75700eadbf27aba7c39418 /gl/alloca.c | |
parent | 210f39bc84cfbb21cd72dc054e43f13815ee0616 (diff) | |
download | monitoring-plugins-fe856aa957978504137c1d425815d4ed8a22be40.tar.gz |
Sync with gnulib - lots of extraneous code removed in preference to GNU code
git-svn-id: https://nagiosplug.svn.sourceforge.net/svnroot/nagiosplug/nagiosplug/trunk@1580 f882894a-f735-0410-b71e-b25c423dba1c
Diffstat (limited to 'gl/alloca.c')
-rw-r--r-- | gl/alloca.c | 489 |
1 files changed, 489 insertions, 0 deletions
diff --git a/gl/alloca.c b/gl/alloca.c new file mode 100644 index 0000000..3a1f4e2 --- /dev/null +++ b/gl/alloca.c | |||
@@ -0,0 +1,489 @@ | |||
1 | /* alloca.c -- allocate automatically reclaimed memory | ||
2 | (Mostly) portable public-domain implementation -- D A Gwyn | ||
3 | |||
4 | This implementation of the PWB library alloca function, | ||
5 | which is used to allocate space off the run-time stack so | ||
6 | that it is automatically reclaimed upon procedure exit, | ||
7 | was inspired by discussions with J. Q. Johnson of Cornell. | ||
8 | J.Otto Tennant <jot@cray.com> contributed the Cray support. | ||
9 | |||
10 | There are some preprocessor constants that can | ||
11 | be defined when compiling for your specific system, for | ||
12 | improved efficiency; however, the defaults should be okay. | ||
13 | |||
14 | The general concept of this implementation is to keep | ||
15 | track of all alloca-allocated blocks, and reclaim any | ||
16 | that are found to be deeper in the stack than the current | ||
17 | invocation. This heuristic does not reclaim storage as | ||
18 | soon as it becomes invalid, but it will do so eventually. | ||
19 | |||
20 | As a special case, alloca(0) reclaims storage without | ||
21 | allocating any. It is a good idea to use alloca(0) in | ||
22 | your main control loop, etc. to force garbage collection. */ | ||
23 | |||
24 | #include <config.h> | ||
25 | |||
26 | #include <alloca.h> | ||
27 | |||
28 | #include <string.h> | ||
29 | #include <stdlib.h> | ||
30 | |||
31 | #ifdef emacs | ||
32 | # include "lisp.h" | ||
33 | # include "blockinput.h" | ||
34 | # ifdef EMACS_FREE | ||
35 | # undef free | ||
36 | # define free EMACS_FREE | ||
37 | # endif | ||
38 | #else | ||
39 | # define memory_full() abort () | ||
40 | #endif | ||
41 | |||
42 | /* If compiling with GCC 2, this file's not needed. */ | ||
43 | #if !defined (__GNUC__) || __GNUC__ < 2 | ||
44 | |||
45 | /* If someone has defined alloca as a macro, | ||
46 | there must be some other way alloca is supposed to work. */ | ||
47 | # ifndef alloca | ||
48 | |||
49 | # ifdef emacs | ||
50 | # ifdef static | ||
51 | /* actually, only want this if static is defined as "" | ||
52 | -- this is for usg, in which emacs must undefine static | ||
53 | in order to make unexec workable | ||
54 | */ | ||
55 | # ifndef STACK_DIRECTION | ||
56 | you | ||
57 | lose | ||
58 | -- must know STACK_DIRECTION at compile-time | ||
59 | /* Using #error here is not wise since this file should work for | ||
60 | old and obscure compilers. */ | ||
61 | # endif /* STACK_DIRECTION undefined */ | ||
62 | # endif /* static */ | ||
63 | # endif /* emacs */ | ||
64 | |||
65 | /* If your stack is a linked list of frames, you have to | ||
66 | provide an "address metric" ADDRESS_FUNCTION macro. */ | ||
67 | |||
68 | # if defined (CRAY) && defined (CRAY_STACKSEG_END) | ||
69 | long i00afunc (); | ||
70 | # define ADDRESS_FUNCTION(arg) (char *) i00afunc (&(arg)) | ||
71 | # else | ||
72 | # define ADDRESS_FUNCTION(arg) &(arg) | ||
73 | # endif | ||
74 | |||
75 | /* Define STACK_DIRECTION if you know the direction of stack | ||
76 | growth for your system; otherwise it will be automatically | ||
77 | deduced at run-time. | ||
78 | |||
79 | STACK_DIRECTION > 0 => grows toward higher addresses | ||
80 | STACK_DIRECTION < 0 => grows toward lower addresses | ||
81 | STACK_DIRECTION = 0 => direction of growth unknown */ | ||
82 | |||
83 | # ifndef STACK_DIRECTION | ||
84 | # define STACK_DIRECTION 0 /* Direction unknown. */ | ||
85 | # endif | ||
86 | |||
87 | # if STACK_DIRECTION != 0 | ||
88 | |||
89 | # define STACK_DIR STACK_DIRECTION /* Known at compile-time. */ | ||
90 | |||
91 | # else /* STACK_DIRECTION == 0; need run-time code. */ | ||
92 | |||
93 | static int stack_dir; /* 1 or -1 once known. */ | ||
94 | # define STACK_DIR stack_dir | ||
95 | |||
96 | static void | ||
97 | find_stack_direction (void) | ||
98 | { | ||
99 | static char *addr = NULL; /* Address of first `dummy', once known. */ | ||
100 | auto char dummy; /* To get stack address. */ | ||
101 | |||
102 | if (addr == NULL) | ||
103 | { /* Initial entry. */ | ||
104 | addr = ADDRESS_FUNCTION (dummy); | ||
105 | |||
106 | find_stack_direction (); /* Recurse once. */ | ||
107 | } | ||
108 | else | ||
109 | { | ||
110 | /* Second entry. */ | ||
111 | if (ADDRESS_FUNCTION (dummy) > addr) | ||
112 | stack_dir = 1; /* Stack grew upward. */ | ||
113 | else | ||
114 | stack_dir = -1; /* Stack grew downward. */ | ||
115 | } | ||
116 | } | ||
117 | |||
118 | # endif /* STACK_DIRECTION == 0 */ | ||
119 | |||
120 | /* An "alloca header" is used to: | ||
121 | (a) chain together all alloca'ed blocks; | ||
122 | (b) keep track of stack depth. | ||
123 | |||
124 | It is very important that sizeof(header) agree with malloc | ||
125 | alignment chunk size. The following default should work okay. */ | ||
126 | |||
127 | # ifndef ALIGN_SIZE | ||
128 | # define ALIGN_SIZE sizeof(double) | ||
129 | # endif | ||
130 | |||
131 | typedef union hdr | ||
132 | { | ||
133 | char align[ALIGN_SIZE]; /* To force sizeof(header). */ | ||
134 | struct | ||
135 | { | ||
136 | union hdr *next; /* For chaining headers. */ | ||
137 | char *deep; /* For stack depth measure. */ | ||
138 | } h; | ||
139 | } header; | ||
140 | |||
141 | static header *last_alloca_header = NULL; /* -> last alloca header. */ | ||
142 | |||
143 | /* Return a pointer to at least SIZE bytes of storage, | ||
144 | which will be automatically reclaimed upon exit from | ||
145 | the procedure that called alloca. Originally, this space | ||
146 | was supposed to be taken from the current stack frame of the | ||
147 | caller, but that method cannot be made to work for some | ||
148 | implementations of C, for example under Gould's UTX/32. */ | ||
149 | |||
150 | void * | ||
151 | alloca (size_t size) | ||
152 | { | ||
153 | auto char probe; /* Probes stack depth: */ | ||
154 | register char *depth = ADDRESS_FUNCTION (probe); | ||
155 | |||
156 | # if STACK_DIRECTION == 0 | ||
157 | if (STACK_DIR == 0) /* Unknown growth direction. */ | ||
158 | find_stack_direction (); | ||
159 | # endif | ||
160 | |||
161 | /* Reclaim garbage, defined as all alloca'd storage that | ||
162 | was allocated from deeper in the stack than currently. */ | ||
163 | |||
164 | { | ||
165 | register header *hp; /* Traverses linked list. */ | ||
166 | |||
167 | # ifdef emacs | ||
168 | BLOCK_INPUT; | ||
169 | # endif | ||
170 | |||
171 | for (hp = last_alloca_header; hp != NULL;) | ||
172 | if ((STACK_DIR > 0 && hp->h.deep > depth) | ||
173 | || (STACK_DIR < 0 && hp->h.deep < depth)) | ||
174 | { | ||
175 | register header *np = hp->h.next; | ||
176 | |||
177 | free (hp); /* Collect garbage. */ | ||
178 | |||
179 | hp = np; /* -> next header. */ | ||
180 | } | ||
181 | else | ||
182 | break; /* Rest are not deeper. */ | ||
183 | |||
184 | last_alloca_header = hp; /* -> last valid storage. */ | ||
185 | |||
186 | # ifdef emacs | ||
187 | UNBLOCK_INPUT; | ||
188 | # endif | ||
189 | } | ||
190 | |||
191 | if (size == 0) | ||
192 | return NULL; /* No allocation required. */ | ||
193 | |||
194 | /* Allocate combined header + user data storage. */ | ||
195 | |||
196 | { | ||
197 | /* Address of header. */ | ||
198 | register header *new; | ||
199 | |||
200 | size_t combined_size = sizeof (header) + size; | ||
201 | if (combined_size < sizeof (header)) | ||
202 | memory_full (); | ||
203 | |||
204 | new = malloc (combined_size); | ||
205 | |||
206 | if (! new) | ||
207 | memory_full (); | ||
208 | |||
209 | new->h.next = last_alloca_header; | ||
210 | new->h.deep = depth; | ||
211 | |||
212 | last_alloca_header = new; | ||
213 | |||
214 | /* User storage begins just after header. */ | ||
215 | |||
216 | return (void *) (new + 1); | ||
217 | } | ||
218 | } | ||
219 | |||
220 | # if defined (CRAY) && defined (CRAY_STACKSEG_END) | ||
221 | |||
222 | # ifdef DEBUG_I00AFUNC | ||
223 | # include <stdio.h> | ||
224 | # endif | ||
225 | |||
226 | # ifndef CRAY_STACK | ||
227 | # define CRAY_STACK | ||
228 | # ifndef CRAY2 | ||
229 | /* Stack structures for CRAY-1, CRAY X-MP, and CRAY Y-MP */ | ||
230 | struct stack_control_header | ||
231 | { | ||
232 | long shgrow:32; /* Number of times stack has grown. */ | ||
233 | long shaseg:32; /* Size of increments to stack. */ | ||
234 | long shhwm:32; /* High water mark of stack. */ | ||
235 | long shsize:32; /* Current size of stack (all segments). */ | ||
236 | }; | ||
237 | |||
238 | /* The stack segment linkage control information occurs at | ||
239 | the high-address end of a stack segment. (The stack | ||
240 | grows from low addresses to high addresses.) The initial | ||
241 | part of the stack segment linkage control information is | ||
242 | 0200 (octal) words. This provides for register storage | ||
243 | for the routine which overflows the stack. */ | ||
244 | |||
245 | struct stack_segment_linkage | ||
246 | { | ||
247 | long ss[0200]; /* 0200 overflow words. */ | ||
248 | long sssize:32; /* Number of words in this segment. */ | ||
249 | long ssbase:32; /* Offset to stack base. */ | ||
250 | long:32; | ||
251 | long sspseg:32; /* Offset to linkage control of previous | ||
252 | segment of stack. */ | ||
253 | long:32; | ||
254 | long sstcpt:32; /* Pointer to task common address block. */ | ||
255 | long sscsnm; /* Private control structure number for | ||
256 | microtasking. */ | ||
257 | long ssusr1; /* Reserved for user. */ | ||
258 | long ssusr2; /* Reserved for user. */ | ||
259 | long sstpid; /* Process ID for pid based multi-tasking. */ | ||
260 | long ssgvup; /* Pointer to multitasking thread giveup. */ | ||
261 | long sscray[7]; /* Reserved for Cray Research. */ | ||
262 | long ssa0; | ||
263 | long ssa1; | ||
264 | long ssa2; | ||
265 | long ssa3; | ||
266 | long ssa4; | ||
267 | long ssa5; | ||
268 | long ssa6; | ||
269 | long ssa7; | ||
270 | long sss0; | ||
271 | long sss1; | ||
272 | long sss2; | ||
273 | long sss3; | ||
274 | long sss4; | ||
275 | long sss5; | ||
276 | long sss6; | ||
277 | long sss7; | ||
278 | }; | ||
279 | |||
280 | # else /* CRAY2 */ | ||
281 | /* The following structure defines the vector of words | ||
282 | returned by the STKSTAT library routine. */ | ||
283 | struct stk_stat | ||
284 | { | ||
285 | long now; /* Current total stack size. */ | ||
286 | long maxc; /* Amount of contiguous space which would | ||
287 | be required to satisfy the maximum | ||
288 | stack demand to date. */ | ||
289 | long high_water; /* Stack high-water mark. */ | ||
290 | long overflows; /* Number of stack overflow ($STKOFEN) calls. */ | ||
291 | long hits; /* Number of internal buffer hits. */ | ||
292 | long extends; /* Number of block extensions. */ | ||
293 | long stko_mallocs; /* Block allocations by $STKOFEN. */ | ||
294 | long underflows; /* Number of stack underflow calls ($STKRETN). */ | ||
295 | long stko_free; /* Number of deallocations by $STKRETN. */ | ||
296 | long stkm_free; /* Number of deallocations by $STKMRET. */ | ||
297 | long segments; /* Current number of stack segments. */ | ||
298 | long maxs; /* Maximum number of stack segments so far. */ | ||
299 | long pad_size; /* Stack pad size. */ | ||
300 | long current_address; /* Current stack segment address. */ | ||
301 | long current_size; /* Current stack segment size. This | ||
302 | number is actually corrupted by STKSTAT to | ||
303 | include the fifteen word trailer area. */ | ||
304 | long initial_address; /* Address of initial segment. */ | ||
305 | long initial_size; /* Size of initial segment. */ | ||
306 | }; | ||
307 | |||
308 | /* The following structure describes the data structure which trails | ||
309 | any stack segment. I think that the description in 'asdef' is | ||
310 | out of date. I only describe the parts that I am sure about. */ | ||
311 | |||
312 | struct stk_trailer | ||
313 | { | ||
314 | long this_address; /* Address of this block. */ | ||
315 | long this_size; /* Size of this block (does not include | ||
316 | this trailer). */ | ||
317 | long unknown2; | ||
318 | long unknown3; | ||
319 | long link; /* Address of trailer block of previous | ||
320 | segment. */ | ||
321 | long unknown5; | ||
322 | long unknown6; | ||
323 | long unknown7; | ||
324 | long unknown8; | ||
325 | long unknown9; | ||
326 | long unknown10; | ||
327 | long unknown11; | ||
328 | long unknown12; | ||
329 | long unknown13; | ||
330 | long unknown14; | ||
331 | }; | ||
332 | |||
333 | # endif /* CRAY2 */ | ||
334 | # endif /* not CRAY_STACK */ | ||
335 | |||
336 | # ifdef CRAY2 | ||
337 | /* Determine a "stack measure" for an arbitrary ADDRESS. | ||
338 | I doubt that "lint" will like this much. */ | ||
339 | |||
340 | static long | ||
341 | i00afunc (long *address) | ||
342 | { | ||
343 | struct stk_stat status; | ||
344 | struct stk_trailer *trailer; | ||
345 | long *block, size; | ||
346 | long result = 0; | ||
347 | |||
348 | /* We want to iterate through all of the segments. The first | ||
349 | step is to get the stack status structure. We could do this | ||
350 | more quickly and more directly, perhaps, by referencing the | ||
351 | $LM00 common block, but I know that this works. */ | ||
352 | |||
353 | STKSTAT (&status); | ||
354 | |||
355 | /* Set up the iteration. */ | ||
356 | |||
357 | trailer = (struct stk_trailer *) (status.current_address | ||
358 | + status.current_size | ||
359 | - 15); | ||
360 | |||
361 | /* There must be at least one stack segment. Therefore it is | ||
362 | a fatal error if "trailer" is null. */ | ||
363 | |||
364 | if (trailer == 0) | ||
365 | abort (); | ||
366 | |||
367 | /* Discard segments that do not contain our argument address. */ | ||
368 | |||
369 | while (trailer != 0) | ||
370 | { | ||
371 | block = (long *) trailer->this_address; | ||
372 | size = trailer->this_size; | ||
373 | if (block == 0 || size == 0) | ||
374 | abort (); | ||
375 | trailer = (struct stk_trailer *) trailer->link; | ||
376 | if ((block <= address) && (address < (block + size))) | ||
377 | break; | ||
378 | } | ||
379 | |||
380 | /* Set the result to the offset in this segment and add the sizes | ||
381 | of all predecessor segments. */ | ||
382 | |||
383 | result = address - block; | ||
384 | |||
385 | if (trailer == 0) | ||
386 | { | ||
387 | return result; | ||
388 | } | ||
389 | |||
390 | do | ||
391 | { | ||
392 | if (trailer->this_size <= 0) | ||
393 | abort (); | ||
394 | result += trailer->this_size; | ||
395 | trailer = (struct stk_trailer *) trailer->link; | ||
396 | } | ||
397 | while (trailer != 0); | ||
398 | |||
399 | /* We are done. Note that if you present a bogus address (one | ||
400 | not in any segment), you will get a different number back, formed | ||
401 | from subtracting the address of the first block. This is probably | ||
402 | not what you want. */ | ||
403 | |||
404 | return (result); | ||
405 | } | ||
406 | |||
407 | # else /* not CRAY2 */ | ||
408 | /* Stack address function for a CRAY-1, CRAY X-MP, or CRAY Y-MP. | ||
409 | Determine the number of the cell within the stack, | ||
410 | given the address of the cell. The purpose of this | ||
411 | routine is to linearize, in some sense, stack addresses | ||
412 | for alloca. */ | ||
413 | |||
414 | static long | ||
415 | i00afunc (long address) | ||
416 | { | ||
417 | long stkl = 0; | ||
418 | |||
419 | long size, pseg, this_segment, stack; | ||
420 | long result = 0; | ||
421 | |||
422 | struct stack_segment_linkage *ssptr; | ||
423 | |||
424 | /* Register B67 contains the address of the end of the | ||
425 | current stack segment. If you (as a subprogram) store | ||
426 | your registers on the stack and find that you are past | ||
427 | the contents of B67, you have overflowed the segment. | ||
428 | |||
429 | B67 also points to the stack segment linkage control | ||
430 | area, which is what we are really interested in. */ | ||
431 | |||
432 | stkl = CRAY_STACKSEG_END (); | ||
433 | ssptr = (struct stack_segment_linkage *) stkl; | ||
434 | |||
435 | /* If one subtracts 'size' from the end of the segment, | ||
436 | one has the address of the first word of the segment. | ||
437 | |||
438 | If this is not the first segment, 'pseg' will be | ||
439 | nonzero. */ | ||
440 | |||
441 | pseg = ssptr->sspseg; | ||
442 | size = ssptr->sssize; | ||
443 | |||
444 | this_segment = stkl - size; | ||
445 | |||
446 | /* It is possible that calling this routine itself caused | ||
447 | a stack overflow. Discard stack segments which do not | ||
448 | contain the target address. */ | ||
449 | |||
450 | while (!(this_segment <= address && address <= stkl)) | ||
451 | { | ||
452 | # ifdef DEBUG_I00AFUNC | ||
453 | fprintf (stderr, "%011o %011o %011o\n", this_segment, address, stkl); | ||
454 | # endif | ||
455 | if (pseg == 0) | ||
456 | break; | ||
457 | stkl = stkl - pseg; | ||
458 | ssptr = (struct stack_segment_linkage *) stkl; | ||
459 | size = ssptr->sssize; | ||
460 | pseg = ssptr->sspseg; | ||
461 | this_segment = stkl - size; | ||
462 | } | ||
463 | |||
464 | result = address - this_segment; | ||
465 | |||
466 | /* If you subtract pseg from the current end of the stack, | ||
467 | you get the address of the previous stack segment's end. | ||
468 | This seems a little convoluted to me, but I'll bet you save | ||
469 | a cycle somewhere. */ | ||
470 | |||
471 | while (pseg != 0) | ||
472 | { | ||
473 | # ifdef DEBUG_I00AFUNC | ||
474 | fprintf (stderr, "%011o %011o\n", pseg, size); | ||
475 | # endif | ||
476 | stkl = stkl - pseg; | ||
477 | ssptr = (struct stack_segment_linkage *) stkl; | ||
478 | size = ssptr->sssize; | ||
479 | pseg = ssptr->sspseg; | ||
480 | result += size; | ||
481 | } | ||
482 | return (result); | ||
483 | } | ||
484 | |||
485 | # endif /* not CRAY2 */ | ||
486 | # endif /* CRAY */ | ||
487 | |||
488 | # endif /* no alloca */ | ||
489 | #endif /* not GCC version 2 */ | ||