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Add torture test for zipos file descriptors

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This change hardens the code for opening /zip/ files using the system
call interface. Thread safety and signal safety has been improved for
file descriptors in general. We now document fixed addresses that are
needed for low level allocations.
This commit is contained in:
Justine Tunney 2022-06-15 16:19:50 -07:00
parent 579080cd4c
commit e466dd0553
44 changed files with 2981 additions and 307 deletions
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67
libc/runtime/clone.c
View file

@ -30,6 +30,7 @@
#include "libc/nt/runtime.h"
#include "libc/nt/thread.h"
#include "libc/nt/thunk/msabi.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/clone.h"
@ -72,34 +73,6 @@ struct CloneArgs {
void *arg;
};
////////////////////////////////////////////////////////////////////////////////
// THREADING RUNTIME
static char tibdefault[64];
extern int __threadcalls_end[];
extern int __threadcalls_start[];
static privileged dontinline void FixupThreadCalls(void) {
/*
* _NOPL("__threadcalls", func)
*
* we have this
*
* 0f 1f 05 b1 19 00 00 nopl func(%rip)
*
* we're going to turn it into this
*
* 67 67 e8 b1 19 00 00 addr32 addr32 call func
*/
__morph_begin();
for (int *p = __threadcalls_start; p < __threadcalls_end; ++p) {
_base[*p + 0] = 0x67;
_base[*p + 1] = 0x67;
_base[*p + 2] = 0xe8;
}
__morph_end();
}
////////////////////////////////////////////////////////////////////////////////
// THE NEW TECHNOLOGY
@ -522,12 +495,11 @@ int sys_clone_linux(int flags, char *stk, int *ptid, int *ctid, void *tls,
* value from the thread by calling __get_tls(). There are a few
* layout expectations imposed by your C library. Those are all
* documented by __initialize_tls() which initializes the parts of
* the first 64 bytes of tls memory that libc cares about. Also
* note that if you decide to use tls once then you must use it
* for everything, since this flag also flips a runtime state that
* enables it for the main thread and functions such as
* __errno_location() will begin assuming they can safely access
* the tls segment register.
* the first 64 bytes of tls memory that libc cares about. This
* flag will transition the C runtime to the `__tls_enabled` state
* automatically. If it's used for one thread, then it must be
* used for all threads. The first time it's used, it must be used
* from the main thread.
* @param arg will be passed to your callback
* @param tls may be used to set the thread local storage segment;
* this parameter is ignored if `CLONE_SETTLS` is not set
@ -539,30 +511,15 @@ int sys_clone_linux(int flags, char *stk, int *ptid, int *ctid, void *tls,
*/
int clone(int (*func)(void *), void *stk, size_t stksz, int flags, void *arg,
int *ptid, void *tls, size_t tlssz, int *ctid) {
int rc, maintid;
int rc;
struct CloneArgs *wt;
// transition program to threaded state
if (!__threaded && (flags & CLONE_THREAD)) {
FixupThreadCalls();
}
if ((flags & CLONE_SETTLS) && !__tls_enabled) {
if (~flags & CLONE_THREAD) {
STRACE("clone() tls w/o thread");
return einval();
}
if (__threaded) {
STRACE("clone() tls/non-tls mixed order");
return einval();
}
maintid = gettid();
__initialize_tls(tibdefault);
*(int *)((char *)tibdefault + 0x38) = maintid;
*(int *)((char *)tibdefault + 0x3c) = __errno;
__install_tls(tibdefault);
__threaded = maintid;
} else if (flags & CLONE_THREAD) {
__threaded = gettid();
__enable_tls();
}
if ((flags & CLONE_THREAD) && !__threaded) {
__enable_threads();
}
if (!func) {