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b6ab06ce | 1 | /* Operating system support for run-time dynamic linker. Generic Unix version. |
171a70b4 | 2 | Copyright (C) 1995-1998,2000-2010,2012 |
4472e1de | 3 | Free Software Foundation, Inc. |
b6ab06ce UD |
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 | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
b6ab06ce UD |
19 | |
20 | #include <assert.h> | |
21 | #include <elf.h> | |
22 | #include <errno.h> | |
23 | #include <fcntl.h> | |
24 | #include <libintl.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <unistd.h> | |
28 | #include <sys/types.h> | |
29 | #include <sys/stat.h> | |
30 | #include <sys/mman.h> | |
31 | #include <ldsodefs.h> | |
eb96ffb0 | 32 | #include <_itoa.h> |
b6ab06ce UD |
33 | #include <fpu_control.h> |
34 | ||
35 | #include <entry.h> | |
36 | #include <dl-machine.h> | |
37 | #include <dl-procinfo.h> | |
38 | #include <dl-osinfo.h> | |
39 | #include <hp-timing.h> | |
40 | #include <tls.h> | |
41 | ||
42 | #ifdef _DL_FIRST_PLATFORM | |
43 | # define _DL_FIRST_EXTRA (_DL_FIRST_PLATFORM + _DL_PLATFORMS_COUNT) | |
44 | #else | |
45 | # define _DL_FIRST_EXTRA _DL_HWCAP_COUNT | |
46 | #endif | |
47 | ||
48 | extern char **_environ attribute_hidden; | |
b1c1949e | 49 | extern char _end[] attribute_hidden; |
b6ab06ce UD |
50 | |
51 | /* Protect SUID program against misuse of file descriptors. */ | |
52 | extern void __libc_check_standard_fds (void); | |
53 | ||
54 | #ifdef NEED_DL_BASE_ADDR | |
55 | ElfW(Addr) _dl_base_addr; | |
56 | #endif | |
57 | int __libc_enable_secure attribute_relro = 0; | |
58 | INTVARDEF(__libc_enable_secure) | |
59 | int __libc_multiple_libcs = 0; /* Defining this here avoids the inclusion | |
60 | of init-first. */ | |
61 | /* This variable contains the lowest stack address ever used. */ | |
62 | void *__libc_stack_end attribute_relro = NULL; | |
63 | rtld_hidden_data_def(__libc_stack_end) | |
64 | static ElfW(auxv_t) *_dl_auxv attribute_relro; | |
965cb60a | 65 | void *_dl_random attribute_relro = NULL; |
b6ab06ce UD |
66 | |
67 | #ifndef DL_FIND_ARG_COMPONENTS | |
68 | # define DL_FIND_ARG_COMPONENTS(cookie, argc, argv, envp, auxp) \ | |
69 | do { \ | |
70 | void **_tmp; \ | |
71 | (argc) = *(long int *) cookie; \ | |
72 | (argv) = (char **) ((long int *) cookie + 1); \ | |
73 | (envp) = (argv) + (argc) + 1; \ | |
74 | for (_tmp = (void **) (envp); *_tmp; ++_tmp) \ | |
75 | continue; \ | |
76 | (auxp) = (void *) ++_tmp; \ | |
77 | } while (0) | |
78 | #endif | |
79 | ||
80 | #ifndef DL_STACK_END | |
81 | # define DL_STACK_END(cookie) ((void *) (cookie)) | |
82 | #endif | |
83 | ||
84 | ElfW(Addr) | |
85 | _dl_sysdep_start (void **start_argptr, | |
86 | void (*dl_main) (const ElfW(Phdr) *phdr, ElfW(Word) phnum, | |
3a56ea26 | 87 | ElfW(Addr) *user_entry, ElfW(auxv_t) *auxv)) |
b6ab06ce UD |
88 | { |
89 | const ElfW(Phdr) *phdr = NULL; | |
90 | ElfW(Word) phnum = 0; | |
91 | ElfW(Addr) user_entry; | |
92 | ElfW(auxv_t) *av; | |
93 | #ifdef HAVE_AUX_SECURE | |
94 | # define set_seen(tag) (tag) /* Evaluate for the side effects. */ | |
95 | # define set_seen_secure() ((void) 0) | |
96 | #else | |
97 | uid_t uid = 0; | |
98 | gid_t gid = 0; | |
99 | unsigned int seen = 0; | |
100 | # define set_seen_secure() (seen = -1) | |
101 | # ifdef HAVE_AUX_XID | |
102 | # define set_seen(tag) (tag) /* Evaluate for the side effects. */ | |
103 | # else | |
104 | # define M(type) (1 << (type)) | |
105 | # define set_seen(tag) seen |= M ((tag)->a_type) | |
106 | # endif | |
107 | #endif | |
108 | #ifdef NEED_DL_SYSINFO | |
109 | uintptr_t new_sysinfo = 0; | |
110 | #endif | |
111 | ||
112 | __libc_stack_end = DL_STACK_END (start_argptr); | |
113 | DL_FIND_ARG_COMPONENTS (start_argptr, _dl_argc, INTUSE(_dl_argv), _environ, | |
114 | _dl_auxv); | |
115 | ||
116 | user_entry = (ElfW(Addr)) ENTRY_POINT; | |
117 | GLRO(dl_platform) = NULL; /* Default to nothing known about the platform. */ | |
118 | ||
119 | for (av = _dl_auxv; av->a_type != AT_NULL; set_seen (av++)) | |
120 | switch (av->a_type) | |
121 | { | |
122 | case AT_PHDR: | |
123 | phdr = (void *) av->a_un.a_val; | |
124 | break; | |
125 | case AT_PHNUM: | |
126 | phnum = av->a_un.a_val; | |
127 | break; | |
128 | case AT_PAGESZ: | |
129 | GLRO(dl_pagesize) = av->a_un.a_val; | |
130 | break; | |
131 | case AT_ENTRY: | |
132 | user_entry = av->a_un.a_val; | |
133 | break; | |
134 | #ifdef NEED_DL_BASE_ADDR | |
135 | case AT_BASE: | |
136 | _dl_base_addr = av->a_un.a_val; | |
137 | break; | |
138 | #endif | |
139 | #ifndef HAVE_AUX_SECURE | |
140 | case AT_UID: | |
141 | case AT_EUID: | |
142 | uid ^= av->a_un.a_val; | |
143 | break; | |
144 | case AT_GID: | |
145 | case AT_EGID: | |
146 | gid ^= av->a_un.a_val; | |
147 | break; | |
148 | #endif | |
149 | case AT_SECURE: | |
150 | #ifndef HAVE_AUX_SECURE | |
151 | seen = -1; | |
152 | #endif | |
153 | INTUSE(__libc_enable_secure) = av->a_un.a_val; | |
154 | break; | |
155 | case AT_PLATFORM: | |
156 | GLRO(dl_platform) = (void *) av->a_un.a_val; | |
157 | break; | |
158 | case AT_HWCAP: | |
159 | GLRO(dl_hwcap) = (unsigned long int) av->a_un.a_val; | |
160 | break; | |
161 | case AT_CLKTCK: | |
162 | GLRO(dl_clktck) = av->a_un.a_val; | |
163 | break; | |
164 | case AT_FPUCW: | |
165 | GLRO(dl_fpu_control) = av->a_un.a_val; | |
166 | break; | |
167 | #ifdef NEED_DL_SYSINFO | |
168 | case AT_SYSINFO: | |
169 | new_sysinfo = av->a_un.a_val; | |
170 | break; | |
171 | #endif | |
172 | #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO | |
173 | case AT_SYSINFO_EHDR: | |
174 | GLRO(dl_sysinfo_dso) = (void *) av->a_un.a_val; | |
175 | break; | |
176 | #endif | |
965cb60a UD |
177 | case AT_RANDOM: |
178 | _dl_random = (void *) av->a_un.a_val; | |
179 | break; | |
b6ab06ce UD |
180 | #ifdef DL_PLATFORM_AUXV |
181 | DL_PLATFORM_AUXV | |
182 | #endif | |
183 | } | |
184 | ||
185 | #ifndef HAVE_AUX_SECURE | |
186 | if (seen != -1) | |
187 | { | |
188 | /* Fill in the values we have not gotten from the kernel through the | |
189 | auxiliary vector. */ | |
190 | # ifndef HAVE_AUX_XID | |
191 | # define SEE(UID, var, uid) \ | |
192 | if ((seen & M (AT_##UID)) == 0) var ^= __get##uid () | |
193 | SEE (UID, uid, uid); | |
194 | SEE (EUID, uid, euid); | |
195 | SEE (GID, gid, gid); | |
196 | SEE (EGID, gid, egid); | |
197 | # endif | |
198 | ||
199 | /* If one of the two pairs of IDs does not match this is a setuid | |
200 | or setgid run. */ | |
201 | INTUSE(__libc_enable_secure) = uid | gid; | |
202 | } | |
203 | #endif | |
204 | ||
205 | #ifndef HAVE_AUX_PAGESIZE | |
206 | if (GLRO(dl_pagesize) == 0) | |
207 | GLRO(dl_pagesize) = __getpagesize (); | |
208 | #endif | |
209 | ||
210 | #if defined NEED_DL_SYSINFO | |
211 | /* Only set the sysinfo value if we also have the vsyscall DSO. */ | |
212 | if (GLRO(dl_sysinfo_dso) != 0 && new_sysinfo) | |
213 | GLRO(dl_sysinfo) = new_sysinfo; | |
214 | #endif | |
215 | ||
216 | #ifdef DL_SYSDEP_INIT | |
217 | DL_SYSDEP_INIT; | |
218 | #endif | |
219 | ||
220 | #ifdef DL_PLATFORM_INIT | |
221 | DL_PLATFORM_INIT; | |
222 | #endif | |
223 | ||
224 | /* Determine the length of the platform name. */ | |
225 | if (GLRO(dl_platform) != NULL) | |
226 | GLRO(dl_platformlen) = strlen (GLRO(dl_platform)); | |
227 | ||
b1c1949e | 228 | if (__sbrk (0) == _end) |
b6ab06ce UD |
229 | /* The dynamic linker was run as a program, and so the initial break |
230 | starts just after our bss, at &_end. The malloc in dl-minimal.c | |
231 | will consume the rest of this page, so tell the kernel to move the | |
232 | break up that far. When the user program examines its break, it | |
233 | will see this new value and not clobber our data. */ | |
234 | __sbrk (GLRO(dl_pagesize) | |
b1c1949e | 235 | - ((_end - (char *) 0) & (GLRO(dl_pagesize) - 1))); |
b6ab06ce UD |
236 | |
237 | /* If this is a SUID program we make sure that FDs 0, 1, and 2 are | |
238 | allocated. If necessary we are doing it ourself. If it is not | |
239 | possible we stop the program. */ | |
240 | if (__builtin_expect (INTUSE(__libc_enable_secure), 0)) | |
241 | __libc_check_standard_fds (); | |
242 | ||
3a56ea26 | 243 | (*dl_main) (phdr, phnum, &user_entry, _dl_auxv); |
b6ab06ce UD |
244 | return user_entry; |
245 | } | |
246 | ||
247 | void | |
248 | internal_function | |
249 | _dl_sysdep_start_cleanup (void) | |
250 | { | |
251 | } | |
252 | ||
253 | void | |
254 | internal_function | |
255 | _dl_show_auxv (void) | |
256 | { | |
257 | char buf[64]; | |
258 | ElfW(auxv_t) *av; | |
259 | ||
260 | /* Terminate string. */ | |
261 | buf[63] = '\0'; | |
262 | ||
263 | /* The following code assumes that the AT_* values are encoded | |
264 | starting from 0 with AT_NULL, 1 for AT_IGNORE, and all other values | |
265 | close by (otherwise the array will be too large). In case we have | |
266 | to support a platform where these requirements are not fulfilled | |
267 | some alternative implementation has to be used. */ | |
268 | for (av = _dl_auxv; av->a_type != AT_NULL; ++av) | |
269 | { | |
270 | static const struct | |
271 | { | |
f53713a8 UD |
272 | const char label[17]; |
273 | enum { unknown = 0, dec, hex, str, ignore } form : 8; | |
b6ab06ce UD |
274 | } auxvars[] = |
275 | { | |
f53713a8 UD |
276 | [AT_EXECFD - 2] = { "EXECFD: ", dec }, |
277 | [AT_EXECFN - 2] = { "EXECFN: ", str }, | |
278 | [AT_PHDR - 2] = { "PHDR: 0x", hex }, | |
279 | [AT_PHENT - 2] = { "PHENT: ", dec }, | |
280 | [AT_PHNUM - 2] = { "PHNUM: ", dec }, | |
281 | [AT_PAGESZ - 2] = { "PAGESZ: ", dec }, | |
282 | [AT_BASE - 2] = { "BASE: 0x", hex }, | |
283 | [AT_FLAGS - 2] = { "FLAGS: 0x", hex }, | |
284 | [AT_ENTRY - 2] = { "ENTRY: 0x", hex }, | |
285 | [AT_NOTELF - 2] = { "NOTELF: ", hex }, | |
286 | [AT_UID - 2] = { "UID: ", dec }, | |
287 | [AT_EUID - 2] = { "EUID: ", dec }, | |
288 | [AT_GID - 2] = { "GID: ", dec }, | |
289 | [AT_EGID - 2] = { "EGID: ", dec }, | |
290 | [AT_PLATFORM - 2] = { "PLATFORM: ", str }, | |
291 | [AT_HWCAP - 2] = { "HWCAP: ", hex }, | |
292 | [AT_CLKTCK - 2] = { "CLKTCK: ", dec }, | |
293 | [AT_FPUCW - 2] = { "FPUCW: ", hex }, | |
294 | [AT_DCACHEBSIZE - 2] = { "DCACHEBSIZE: 0x", hex }, | |
295 | [AT_ICACHEBSIZE - 2] = { "ICACHEBSIZE: 0x", hex }, | |
296 | [AT_UCACHEBSIZE - 2] = { "UCACHEBSIZE: 0x", hex }, | |
297 | [AT_IGNOREPPC - 2] = { "IGNOREPPC", ignore }, | |
298 | [AT_SECURE - 2] = { "SECURE: ", dec }, | |
299 | [AT_BASE_PLATFORM - 2] = { "BASE_PLATFORM:", str }, | |
300 | [AT_SYSINFO - 2] = { "SYSINFO: 0x", hex }, | |
301 | [AT_SYSINFO_EHDR - 2] = { "SYSINFO_EHDR: 0x", hex }, | |
302 | [AT_RANDOM - 2] = { "RANDOM: 0x", hex }, | |
b6ab06ce UD |
303 | }; |
304 | unsigned int idx = (unsigned int) (av->a_type - 2); | |
305 | ||
171a70b4 PP |
306 | if ((unsigned int) av->a_type < 2u |
307 | || (idx < sizeof (auxvars) / sizeof (auxvars[0]) | |
308 | && auxvars[idx].form == ignore)) | |
b6ab06ce UD |
309 | continue; |
310 | ||
311 | assert (AT_NULL == 0); | |
312 | assert (AT_IGNORE == 1); | |
313 | ||
314 | if (av->a_type == AT_HWCAP) | |
315 | { | |
316 | /* This is handled special. */ | |
317 | if (_dl_procinfo (av->a_un.a_val) == 0) | |
318 | continue; | |
319 | } | |
320 | ||
321 | if (idx < sizeof (auxvars) / sizeof (auxvars[0]) | |
322 | && auxvars[idx].form != unknown) | |
323 | { | |
324 | const char *val = (char *) av->a_un.a_val; | |
325 | ||
326 | if (__builtin_expect (auxvars[idx].form, dec) == dec) | |
327 | val = _itoa ((unsigned long int) av->a_un.a_val, | |
328 | buf + sizeof buf - 1, 10, 0); | |
329 | else if (__builtin_expect (auxvars[idx].form, hex) == hex) | |
330 | val = _itoa ((unsigned long int) av->a_un.a_val, | |
331 | buf + sizeof buf - 1, 16, 0); | |
332 | ||
f53713a8 | 333 | _dl_printf ("AT_%s%s\n", auxvars[idx].label, val); |
b6ab06ce UD |
334 | |
335 | continue; | |
336 | } | |
337 | ||
338 | /* Unknown value: print a generic line. */ | |
339 | char buf2[17]; | |
fbb04b35 | 340 | buf2[sizeof (buf2) - 1] = '\0'; |
b6ab06ce UD |
341 | const char *val2 = _itoa ((unsigned long int) av->a_un.a_val, |
342 | buf2 + sizeof buf2 - 1, 16, 0); | |
343 | const char *val = _itoa ((unsigned long int) av->a_type, | |
344 | buf + sizeof buf - 1, 16, 0); | |
345 | _dl_printf ("AT_??? (0x%s): 0x%s\n", val, val2); | |
346 | } | |
347 | } | |
348 | ||
349 | ||
350 | /* Return an array of useful/necessary hardware capability names. */ | |
351 | const struct r_strlenpair * | |
352 | internal_function | |
353 | _dl_important_hwcaps (const char *platform, size_t platform_len, size_t *sz, | |
354 | size_t *max_capstrlen) | |
355 | { | |
356 | /* Determine how many important bits are set. */ | |
357 | uint64_t masked = GLRO(dl_hwcap) & GLRO(dl_hwcap_mask); | |
358 | size_t cnt = platform != NULL; | |
359 | size_t n, m; | |
360 | size_t total; | |
361 | struct r_strlenpair *temp; | |
362 | struct r_strlenpair *result; | |
363 | struct r_strlenpair *rp; | |
364 | char *cp; | |
365 | ||
366 | /* Count the number of bits set in the masked value. */ | |
367 | for (n = 0; (~((1ULL << n) - 1) & masked) != 0; ++n) | |
368 | if ((masked & (1ULL << n)) != 0) | |
369 | ++cnt; | |
370 | ||
371 | #if (defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO) && defined SHARED | |
372 | /* The system-supplied DSO can contain a note of type 2, vendor "GNU". | |
373 | This gives us a list of names to treat as fake hwcap bits. */ | |
374 | ||
375 | const char *dsocaps = NULL; | |
376 | size_t dsocapslen = 0; | |
377 | if (GLRO(dl_sysinfo_map) != NULL) | |
378 | { | |
379 | const ElfW(Phdr) *const phdr = GLRO(dl_sysinfo_map)->l_phdr; | |
380 | const ElfW(Word) phnum = GLRO(dl_sysinfo_map)->l_phnum; | |
381 | for (uint_fast16_t i = 0; i < phnum; ++i) | |
382 | if (phdr[i].p_type == PT_NOTE) | |
383 | { | |
384 | const ElfW(Addr) start = (phdr[i].p_vaddr | |
385 | + GLRO(dl_sysinfo_map)->l_addr); | |
386 | const struct | |
387 | { | |
388 | ElfW(Word) vendorlen; | |
389 | ElfW(Word) datalen; | |
390 | ElfW(Word) type; | |
391 | } *note = (const void *) start; | |
392 | while ((ElfW(Addr)) (note + 1) - start < phdr[i].p_memsz) | |
393 | { | |
394 | #define ROUND(len) (((len) + sizeof (ElfW(Word)) - 1) & -sizeof (ElfW(Word))) | |
4472e1de | 395 | if (note->type == NT_GNU_HWCAP |
b6ab06ce UD |
396 | && note->vendorlen == sizeof "GNU" |
397 | && !memcmp ((note + 1), "GNU", sizeof "GNU") | |
398 | && note->datalen > 2 * sizeof (ElfW(Word)) + 2) | |
399 | { | |
400 | const ElfW(Word) *p = ((const void *) (note + 1) | |
401 | + ROUND (sizeof "GNU")); | |
402 | cnt += *p++; | |
403 | ++p; /* Skip mask word. */ | |
404 | dsocaps = (const char *) p; | |
405 | dsocapslen = note->datalen - sizeof *p * 2; | |
406 | break; | |
407 | } | |
408 | note = ((const void *) (note + 1) | |
409 | + ROUND (note->vendorlen) + ROUND (note->datalen)); | |
7c22c7ec | 410 | #undef ROUND |
b6ab06ce UD |
411 | } |
412 | if (dsocaps != NULL) | |
413 | break; | |
414 | } | |
415 | } | |
416 | #endif | |
417 | ||
b6ab06ce UD |
418 | /* For TLS enabled builds always add 'tls'. */ |
419 | ++cnt; | |
b6ab06ce UD |
420 | |
421 | /* Create temporary data structure to generate result table. */ | |
422 | temp = (struct r_strlenpair *) alloca (cnt * sizeof (*temp)); | |
423 | m = 0; | |
424 | #if defined NEED_DL_SYSINFO || defined NEED_DL_SYSINFO_DSO | |
425 | if (dsocaps != NULL) | |
426 | { | |
427 | const ElfW(Word) mask = ((const ElfW(Word) *) dsocaps)[-1]; | |
428 | GLRO(dl_hwcap) |= (uint64_t) mask << _DL_FIRST_EXTRA; | |
5dbc3b6c RM |
429 | /* Note that we add the dsocaps to the set already chosen by the |
430 | LD_HWCAP_MASK environment variable (or default HWCAP_IMPORTANT). | |
431 | So there is no way to request ignoring an OS-supplied dsocap | |
432 | string and bit like you can ignore an OS-supplied HWCAP bit. */ | |
433 | GLRO(dl_hwcap_mask) |= (uint64_t) mask << _DL_FIRST_EXTRA; | |
b6ab06ce UD |
434 | size_t len; |
435 | for (const char *p = dsocaps; p < dsocaps + dsocapslen; p += len + 1) | |
436 | { | |
437 | uint_fast8_t bit = *p++; | |
438 | len = strlen (p); | |
439 | ||
440 | /* Skip entries that are not enabled in the mask word. */ | |
441 | if (__builtin_expect (mask & ((ElfW(Word)) 1 << bit), 1)) | |
442 | { | |
443 | temp[m].str = p; | |
444 | temp[m].len = len; | |
445 | ++m; | |
446 | } | |
447 | else | |
448 | --cnt; | |
449 | } | |
450 | } | |
451 | #endif | |
452 | for (n = 0; masked != 0; ++n) | |
453 | if ((masked & (1ULL << n)) != 0) | |
454 | { | |
455 | temp[m].str = _dl_hwcap_string (n); | |
456 | temp[m].len = strlen (temp[m].str); | |
457 | masked ^= 1ULL << n; | |
458 | ++m; | |
459 | } | |
460 | if (platform != NULL) | |
461 | { | |
462 | temp[m].str = platform; | |
463 | temp[m].len = platform_len; | |
464 | ++m; | |
465 | } | |
11bf311e | 466 | |
b6ab06ce UD |
467 | temp[m].str = "tls"; |
468 | temp[m].len = 3; | |
469 | ++m; | |
11bf311e | 470 | |
b6ab06ce UD |
471 | assert (m == cnt); |
472 | ||
473 | /* Determine the total size of all strings together. */ | |
474 | if (cnt == 1) | |
475 | total = temp[0].len + 1; | |
476 | else | |
477 | { | |
1311e86e UD |
478 | total = temp[0].len + temp[cnt - 1].len + 2; |
479 | if (cnt > 2) | |
480 | { | |
481 | total <<= 1; | |
482 | for (n = 1; n + 1 < cnt; ++n) | |
483 | total += temp[n].len + 1; | |
484 | if (cnt > 3 | |
485 | && (cnt >= sizeof (size_t) * 8 | |
486 | || total + (sizeof (*result) << 3) | |
487 | >= (1UL << (sizeof (size_t) * 8 - cnt + 3)))) | |
488 | _dl_signal_error (ENOMEM, NULL, NULL, | |
8e46c99f | 489 | N_("cannot create capability list")); |
1311e86e UD |
490 | |
491 | total <<= cnt - 3; | |
492 | } | |
b6ab06ce UD |
493 | } |
494 | ||
495 | /* The result structure: we use a very compressed way to store the | |
496 | various combinations of capability names. */ | |
497 | *sz = 1 << cnt; | |
498 | result = (struct r_strlenpair *) malloc (*sz * sizeof (*result) + total); | |
499 | if (result == NULL) | |
11bf311e UD |
500 | _dl_signal_error (ENOMEM, NULL, NULL, |
501 | N_("cannot create capability list")); | |
b6ab06ce UD |
502 | |
503 | if (cnt == 1) | |
504 | { | |
505 | result[0].str = (char *) (result + *sz); | |
506 | result[0].len = temp[0].len + 1; | |
507 | result[1].str = (char *) (result + *sz); | |
508 | result[1].len = 0; | |
509 | cp = __mempcpy ((char *) (result + *sz), temp[0].str, temp[0].len); | |
510 | *cp = '/'; | |
511 | *sz = 2; | |
512 | *max_capstrlen = result[0].len; | |
513 | ||
514 | return result; | |
515 | } | |
516 | ||
517 | /* Fill in the information. This follows the following scheme | |
518 | (indeces from TEMP for four strings): | |
519 | entry #0: 0, 1, 2, 3 binary: 1111 | |
3a56ea26 AK |
520 | #1: 0, 1, 3 1101 |
521 | #2: 0, 2, 3 1011 | |
522 | #3: 0, 3 1001 | |
b6ab06ce UD |
523 | This allows the representation of all possible combinations of |
524 | capability names in the string. First generate the strings. */ | |
525 | result[1].str = result[0].str = cp = (char *) (result + *sz); | |
526 | #define add(idx) \ | |
527 | cp = __mempcpy (__mempcpy (cp, temp[idx].str, temp[idx].len), "/", 1); | |
528 | if (cnt == 2) | |
529 | { | |
530 | add (1); | |
531 | add (0); | |
532 | } | |
533 | else | |
534 | { | |
535 | n = 1 << (cnt - 1); | |
536 | do | |
537 | { | |
538 | n -= 2; | |
539 | ||
540 | /* We always add the last string. */ | |
541 | add (cnt - 1); | |
542 | ||
543 | /* Add the strings which have the bit set in N. */ | |
544 | for (m = cnt - 2; m > 0; --m) | |
545 | if ((n & (1 << m)) != 0) | |
546 | add (m); | |
547 | ||
548 | /* Always add the first string. */ | |
549 | add (0); | |
550 | } | |
551 | while (n != 0); | |
552 | } | |
553 | #undef add | |
554 | ||
555 | /* Now we are ready to install the string pointers and length. */ | |
556 | for (n = 0; n < (1UL << cnt); ++n) | |
557 | result[n].len = 0; | |
558 | n = cnt; | |
559 | do | |
560 | { | |
561 | size_t mask = 1 << --n; | |
562 | ||
563 | rp = result; | |
564 | for (m = 1 << cnt; m > 0; ++rp) | |
565 | if ((--m & mask) != 0) | |
566 | rp->len += temp[n].len + 1; | |
567 | } | |
568 | while (n != 0); | |
569 | ||
570 | /* The first half of the strings all include the first string. */ | |
571 | n = (1 << cnt) - 2; | |
572 | rp = &result[2]; | |
573 | while (n != (1UL << (cnt - 1))) | |
574 | { | |
575 | if ((--n & 1) != 0) | |
576 | rp[0].str = rp[-2].str + rp[-2].len; | |
577 | else | |
578 | rp[0].str = rp[-1].str; | |
579 | ++rp; | |
580 | } | |
581 | ||
582 | /* The second half starts right after the first part of the string of | |
583 | the corresponding entry in the first half. */ | |
584 | do | |
585 | { | |
586 | rp[0].str = rp[-(1 << (cnt - 1))].str + temp[cnt - 1].len + 1; | |
587 | ++rp; | |
588 | } | |
589 | while (--n != 0); | |
590 | ||
591 | /* The maximum string length. */ | |
592 | *max_capstrlen = result[0].len; | |
593 | ||
594 | return result; | |
595 | } |