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Commit	Line	Data
	1	/*
	2	* Copyright (c) 2016 Apple Inc. All rights reserved.
	3	*/
	4
	5	#include "options.h"
	6	#include "dyld_shared_cache.h"
	7	#include "utils.h"
	8
	9	#include <stdio.h>
	10	#include <string.h>
	11	#include <strings.h>
	12	#include <stdlib.h>
	13	#include <stdarg.h>
	14	#include <unistd.h>
	15	#include <errno.h>
	16	#include <fts.h>
	17	#include <fcntl.h>
	18	#include <assert.h>
	19	#include <sys/mman.h>
	20	#include <sys/stat.h>
	21
	22	static const size_t dyld_cache_header_size = sizeof (struct copied_dyld_cache_header);
	23
	24	/*
	25	* The shared cache must both contain the magic ID and
	26	* match the uuid we discovered via dyld's information.
	27	* Assumes that the dyld_cache_header grows in a binary compatible fashion.
	28	*/
	29	bool
	30	get_uuid_from_shared_cache_mapping(const void *addr, size_t size, uuid_t out)
	31	{
	32	const struct copied_dyld_cache_header *ch = addr;
	33	if (size < sizeof (*ch))
	34	return false;
	35	static const char prefix[] = "dyld_v";
	36	if (strncmp(ch->magic, prefix, strlen(prefix)) != 0)
	37	return false;
	38	uuid_copy(out, ch->uuid);
	39	return true;
	40	}
	41
	42	/*
	43	* Look in the known places to see if we can find this one ..
	44	*/
	45	char *
	46	shared_cache_filename(const uuid_t uu)
	47	{
	48	assert(!uuid_is_null(uu));
	49	static char *sc_argv[] = {
	50	#if defined(__i386__) \|\| defined(__x86_64__)
	51	"/var/db/dyld",
	52	#elif defined(__arm__) \|\| defined(__arm64__)
	53	"/System/Library/Caches/com.apple.dyld",
	54	#else
	55	#error undefined
	56	#endif
	57	NULL
	58	};
	59	char *nm = NULL;
	60	FTS *fts = fts_open(sc_argv, FTS_NOCHDIR \| FTS_LOGICAL \| FTS_XDEV, NULL);
	61	if (NULL != fts) {
	62	FTSENT *fe;
	63	while (NULL != (fe = fts_read(fts))) {
	64	if ((fe->fts_info & FTS_F) == 0 \|\|
	65	(fe->fts_info & FTS_ERR) != 0)
	66	continue;
	67
	68	static const char prefix[] = "dyld_shared_cache_";
	69	if (strncmp(fe->fts_name, prefix, strlen(prefix)) != 0)
	70	continue;
	71
	72	if (fe->fts_statp->st_size < (off_t)dyld_cache_header_size)
	73	continue;
	74
	75	int d = open(fe->fts_accpath, O_RDONLY);
	76	if (-1 == d) {
	77	if (OPTIONS_DEBUG(opt, 1))
	78	printf("%s: cannot open - %s\n", fe->fts_accpath, strerror(errno));
	79	continue;
	80	}
	81	void *addr = mmap(NULL, dyld_cache_header_size, PROT_READ, MAP_PRIVATE, d, 0);
	82	close(d);
	83	if ((void *)-1 == addr) {
	84	if (OPTIONS_DEBUG(opt, 1))
	85	printf("%s: cannot mmap - %s\n", fe->fts_accpath, strerror(errno));
	86	continue;
	87	}
	88	uuid_t scuuid;
	89	uuid_clear(scuuid);
	90	if (get_uuid_from_shared_cache_mapping(addr, dyld_cache_header_size, scuuid)) {
	91	if (uuid_compare(uu, scuuid) == 0)
	92	nm = strdup(fe->fts_accpath);
	93	else if (OPTIONS_DEBUG(opt, 3)) {
	94	uuid_string_t scstr;
	95	uuid_unparse_lower(scuuid, scstr);
	96	printf("%s: shared cache mismatch (%s)\n", fe->fts_accpath, scstr);
	97	}
	98	}
	99	munmap(addr, dyld_cache_header_size);
	100	if (NULL != nm)
	101	break;
	102	}
	103	}
	104	if (fts)
	105	fts_close(fts);
	106	return nm;
	107	}