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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	*/
	28	bool
	29	get_uuid_from_shared_cache_mapping(const void *addr, size_t size, uuid_t out)
	30	{
	31	const struct copied_dyld_cache_header *ch = addr;
	32	if (size < sizeof (*ch))
	33	return false;
	34	static const char prefix[] = "dyld_v1 ";
	35	if (strncmp(ch->magic, prefix, strlen(prefix)) != 0)
	36	return false;
	37	uuid_copy(out, ch->uuid);
	38	return true;
	39	}
	40
	41	/*
	42	* Look in the known places to see if we can find this one ..
	43	*/
	44	char *
	45	shared_cache_filename(const uuid_t uu)
	46	{
	47	assert(!uuid_is_null(uu));
	48	static char *sc_argv[] = {
	49	#if defined(__i386__) \|\| defined(__x86_64__)
	50	"/var/db/dyld",
	51	#elif defined(__arm__) \|\| defined(__arm64__)
	52	"/System/Library/Caches/com.apple.dyld",
	53	#else
	54	#error undefined
	55	#endif
	56	NULL
	57	};
	58	char *nm = NULL;
	59	FTS *fts = fts_open(sc_argv, FTS_NOCHDIR \| FTS_LOGICAL \| FTS_XDEV, NULL);
	60	if (NULL != fts) {
	61	FTSENT *fe;
	62	while (NULL != (fe = fts_read(fts))) {
	63	if ((fe->fts_info & FTS_F) == 0 \|\|
	64	(fe->fts_info & FTS_ERR) != 0)
	65	continue;
	66
	67	static const char prefix[] = "dyld_shared_cache_";
	68	if (strncmp(fe->fts_name, prefix, strlen(prefix)) != 0)
	69	continue;
	70
	71	if (fe->fts_statp->st_size < (off_t)dyld_cache_header_size)
	72	continue;
	73
	74	int d = open(fe->fts_accpath, O_RDONLY);
	75	if (-1 == d) {
	76	if (opt->debug)
	77	printf("%s: cannot open - %s\n", fe->fts_accpath, strerror(errno));
	78	continue;
	79	}
	80	void *addr = mmap(NULL, dyld_cache_header_size, PROT_READ, MAP_PRIVATE, d, 0);
	81	close(d);
	82	if ((void *)-1 == addr) {
	83	if (opt->debug)
	84	printf("%s: cannot mmap - %s\n", fe->fts_accpath, strerror(errno));
	85	continue;
	86	}
	87	uuid_t scuuid;
	88	uuid_clear(scuuid);
	89	if (get_uuid_from_shared_cache_mapping(addr, dyld_cache_header_size, scuuid)) {
	90	if (uuid_compare(uu, scuuid) == 0)
	91	nm = strdup(fe->fts_accpath);
	92	else if (opt->debug) {
	93	uuid_string_t scstr;
	94	uuid_unparse_lower(scuuid, scstr);
	95	printf("%s: shared cache mismatch (%s)\n", fe->fts_accpath, scstr);
	96	}
	97	}
	98	munmap(addr, dyld_cache_header_size);
	99	if (NULL != nm)
	100	break;
	101	}
	102	}
	103	if (fts)
	104	fts_close(fts);
	105	return nm;
	106	}