rms/libfaketime
1
0
Fork 0
mirror of https://github.com/wolfcw/libfaketime.git synced 2026-05-17 00:26:16 +03:00
Code Issues Packages Projects Releases Wiki Activity

Merge pull request #501 from usertam/patch/clean-up-and-readme

Browse Source 
Fix compiler warnings and update README.OSX
This commit is contained in:
Wolfgang Hommel
2025-06-09 10:24:59 +02:00
committed by GitHub
parent 9f7b304dbe 77ae25f529
commit cb48e454be
2 changed files with 55 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
README.OSX
View File

@@ -166,3 +166,50 @@ The environment variable FAKETIME can be changed at application run-time
and always takes precedence over other user-controlled settings. It can
be re-set to 0 (zero) to work around potential incompatibilities or if
you do not want libfaketime applied to your software.
5) Working with the new arm64e system binaries in Apple Silicon
---------------------------------------------------------------
Since Apple Silicon, Apple started shipping system binaries compiled against
the `arm64e` ABI. This new ABI enforces Pointer Authentication Codes (PACs),
and enforces assembly instructions to sign and check pointer signatures to
prevent malicious control flow altering.
$ file /bin/date
/bin/date: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64e:Mach-O 64-bit executable arm64e]
/bin/date (for architecture x86_64): Mach-O 64-bit executable x86_64
/bin/date (for architecture arm64e): Mach-O 64-bit executable arm64e
Most importantly, the new `arm64e` ABI is incompatible with the normal `arm64`
ABI we are used to; this is done so that everything `arm64e` is PAC-enforced.
As a result, this will happen when we try to hook naive `arm64` libfaketime on
system binaries (and vice versa with `arm64e` libfaketime on `arm64` binaries):
$ DYLD_INSERT_LIBRARIES=libfaketime.1.dylib /bin/date
dyld[5788]: terminating because inserted dylib 'libfaketime.1.dylib' could not be loaded:
tried: 'libfaketime.1.dylib' (mach-o file, but is an incompatible architecture (have 'arm64', need 'arm64e'))
Since PR #497, we now compile libfaketime with a fat library/binary setup, so
that we support both ABIs at the same time:
$ file libfaketime.1.dylib
libfaketime.1.dylib: Mach-O universal binary with 2 architectures: [arm64:Mach-O 64-bit dynamically linked shared library arm64] [arm64e:Mach-O 64-bit dynamically linked shared library arm64e]
libfaketime.1.dylib (for architecture arm64): Mach-O 64-bit dynamically linked shared library arm64
libfaketime.1.dylib (for architecture arm64e): Mach-O 64-bit dynamically linked shared library arm64e
Unfortunately, Apple does not support running third-party `arm64e` code yet,
since the ABI is still unstable. This means that you cannot use libfaketime
on system `arm64e` binaries out of the box, at the time of writing.
If you really need to, you may disable SIP in the recovery terminal:
(in recovery) # csrutil disable
And enable the experimental ABI after boot:
(in regular boot) $ sudo nvram boot-args=-arm64e_preview_abi
Then `arm64e` should work as-is. This use case is rather uncommon since most
userspace binaries will remain `arm64` for the time being, until Apple really
doubles down on `arm64e`. Regardless, we should be prepared for that.

24
src/libfaketime.c
View File

@@ -208,10 +208,12 @@ static int (*real_xstat) (int, const char *, struct stat *);
static int (*real_fxstat) (int, int, struct stat *);
static int (*real_fxstatat) (int, int, const char *, struct stat *, int);
static int (*real_lxstat) (int, const char *, struct stat *);
#if !defined(__APPLE__) || !__DARWIN_ONLY_64_BIT_INO_T
static int (*real_xstat64) (int, const char *, struct stat64 *);
static int (*real_fxstat64) (int, int , struct stat64 *);
static int (*real_fxstatat64) (int, int , const char *, struct stat64 *, int);
static int (*real_lxstat64) (int, const char *, struct stat64 *);
#endif
#ifdef STATX_TYPE
static int (*real_statx) (int dirfd, const char *pathname, int flags, unsigned int mask, struct statx *statxbuf);
#endif
@@ -983,6 +985,7 @@ static inline void fake_statbuf (struct stat *buf) {
#endif
}
#ifndef __APPLE__
static inline void fake_stat64buf (struct stat64 *buf) {
#ifndef st_atime
lock_for_stat();
@@ -992,18 +995,13 @@ static inline void fake_stat64buf (struct stat64 *buf) {
unlock_for_stat();
#else
lock_for_stat();
#ifndef __APPLE__
fake_clock_gettime(CLOCK_REALTIME, &buf->st_ctim);
fake_clock_gettime(CLOCK_REALTIME, &buf->st_atim);
fake_clock_gettime(CLOCK_REALTIME, &buf->st_mtim);
#else
fake_clock_gettime(CLOCK_REALTIME, &buf->st_ctimespec);
fake_clock_gettime(CLOCK_REALTIME, &buf->st_atimespec);
fake_clock_gettime(CLOCK_REALTIME, &buf->st_mtimespec);
#endif
unlock_for_stat();
#endif
}
#endif
/* macOS dyld interposing uses the function's real name instead of real_name */
#ifdef MACOS_DYLD_INTERPOSE
@@ -1113,25 +1111,19 @@ int __lxstat (int ver, const char *path, struct stat *buf)
{
STAT_HANDLER(lxstat, buf, ver, path, buf);
}
#endif
#ifndef __APPLE__
/* Contributed by Philipp Hachtmann in version 0.6 */
int __xstat64 (int ver, const char *path, struct stat64 *buf)
{
STAT64_HANDLER(xstat64, buf, ver, path, buf);
}
#endif
#ifndef __APPLE__
/* Contributed by Philipp Hachtmann in version 0.6 */
int __fxstat64 (int ver, int fildes, struct stat64 *buf)
{
STAT64_HANDLER(fxstat64, buf, ver, fildes, buf);
}
#endif
#ifndef __APPLE__
/* Added in v0.8 as suggested by Daniel Kahn Gillmor */
#ifndef NO_ATFILE
int __fxstatat64 (int ver, int fildes, const char *filename, struct stat64 *buf, int flag)
@@ -1139,16 +1131,14 @@ int __fxstatat64 (int ver, int fildes, const char *filename, struct stat64 *buf,
STAT64_HANDLER(fxstatat64, buf, ver, fildes, filename, buf, flag);
}
#endif
#endif
#ifndef __APPLE__
/* Contributed by Philipp Hachtmann in version 0.6 */
int __lxstat64 (int ver, const char *path, struct stat64 *buf)
{
STAT64_HANDLER(lxstat64, buf, ver, path, buf);
}
#endif
#endif
#endif /* ifndef __APPLE__ */
#endif /* ifdef FAKE_STAT */
#ifdef STATX_TYPE
static inline void fake_statx_timestamp(struct statx_timestamp* p)
@@ -2689,10 +2679,12 @@ static void ftpl_really_init(void)
real_fxstat = dlsym(RTLD_NEXT, "__fxstat");
real_fxstatat = dlsym(RTLD_NEXT, "__fxstatat");
real_lxstat = dlsym(RTLD_NEXT, "__lxstat");
#if !defined(__APPLE__) || !__DARWIN_ONLY_64_BIT_INO_T
real_xstat64 = dlsym(RTLD_NEXT,"__xstat64");
real_fxstat64 = dlsym(RTLD_NEXT, "__fxstat64");
real_fxstatat64 = dlsym(RTLD_NEXT, "__fxstatat64");
real_lxstat64 = dlsym(RTLD_NEXT, "__lxstat64");
#endif
#ifdef STATX_TYPE
real_statx = dlsym(RTLD_NEXT, "statx");
#endif