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Improve memory safety
This commit makes numerous refinements to cosmopolitan memory handling.
The default stack size has been reduced from 2mb to 128kb. A new macro
is now provided so you can easily reconfigure the stack size to be any
value you want. Work around the breaking change by adding to your main:
STATIC_STACK_SIZE(0x00200000); // 2mb stack
If you're not sure how much stack you need, then you can use:
STATIC_YOINK("stack_usage_logging");
After which you can `sort -nr o/$MODE/stack.log`. Based on the unit test
suite, nothing in the Cosmopolitan repository (except for Python) needs
a stack size greater than 30kb. There are also new macros for detecting
the size and address of the stack at runtime, e.g. GetStackAddr(). We
also now support sigaltstack() so if you want to see nice looking crash
reports whenever a stack overflow happens, you can put this in main():
ShowCrashReports();
Under `make MODE=dbg` and `make MODE=asan` the unit testing framework
will now automatically print backtraces of memory allocations when
things like memory leaks happen. Bugs are now fixed in ASAN global
variable overrun detection. The memtrack and asan runtimes also handle
edge cases now. The new tools helped to identify a few memory leaks,
which are fixed by this change.
This change should fix an issue reported in #288 with ARG_MAX limits.
Fixing this doubled the performance of MKDEPS.COM and AR.COM yet again.
This commit is contained in:
Justine Tunney
parent
a0b39f886c
commit
226aaf3547
317 changed files with 6474 additions and 3993 deletions
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@ -16,41 +16,44 @@
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/thread/create.h"
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#include "libc/errno.h"
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#include "libc/linux/clone.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/consts/nr.h"
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#include "libc/sysv/consts/clone.h"
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#include "libc/sysv/consts/map.h"
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#include "libc/sysv/consts/nr.h"
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#include "libc/sysv/consts/prot.h"
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#include "libc/errno.h"
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#include "libc/thread/create.h"
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static cthread_t _thread_allocate(const cthread_attr_t* attr) {
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size_t stacksize = attr->stacksize;
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size_t guardsize = attr->guardsize;
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// FIXME: properly count TLS size
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size_t tlssize = 0;
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size_t totalsize = 3*guardsize + stacksize + tlssize + sizeof(struct cthread_descriptor_t);
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totalsize = (totalsize + PAGESIZE-1) & -PAGESIZE;
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uintptr_t mem = (uintptr_t)mmap(NULL, totalsize, PROT_NONE, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
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size_t totalsize =
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3 * guardsize + stacksize + tlssize + sizeof(struct cthread_descriptor_t);
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totalsize = (totalsize + PAGESIZE - 1) & -PAGESIZE;
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uintptr_t mem = (uintptr_t)mmap(NULL, totalsize, PROT_NONE,
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MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
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if (mem == -1) return NULL;
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void* alloc_bottom = (void*) mem;
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void* alloc_bottom = (void*)mem;
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void* stack_bottom = (void*)(mem + guardsize);
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void* stack_top = (void*)(mem + guardsize + stacksize);
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void* tls_bottom = (void*)(mem + guardsize + stacksize + guardsize);
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void* tls_top = (void*)(mem + totalsize - guardsize);
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void* alloc_top = (void*)(mem + totalsize);
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if (mprotect(stack_bottom, (uintptr_t)stack_top - (uintptr_t)stack_bottom, PROT_READ | PROT_WRITE) != 0 ||
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mprotect(tls_bottom, (uintptr_t)tls_top - (uintptr_t)tls_bottom, PROT_READ | PROT_WRITE) != 0) {
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if (mprotect(stack_bottom, (uintptr_t)stack_top - (uintptr_t)stack_bottom,
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PROT_READ | PROT_WRITE) != 0 ||
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mprotect(tls_bottom, (uintptr_t)tls_top - (uintptr_t)tls_bottom,
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PROT_READ | PROT_WRITE) != 0) {
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munmap(alloc_bottom, totalsize);
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return NULL;
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}
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cthread_t td = (cthread_t)tls_top - 1;
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td->self = td;
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td->stack.top = stack_top;
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@ -59,45 +62,48 @@ static cthread_t _thread_allocate(const cthread_attr_t* attr) {
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td->tls.bottom = tls_bottom;
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td->alloc.top = alloc_top;
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td->alloc.bottom = alloc_bottom;
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td->state = (attr->mode & CTHREAD_CREATE_DETACHED) ? cthread_detached : cthread_started;
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td->state = (attr->mode & CTHREAD_CREATE_DETACHED) ? cthread_detached
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: cthread_started;
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return td;
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}
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int cthread_create(cthread_t*restrict p, const cthread_attr_t*restrict attr, int (*func)(void*), void*restrict arg) {
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extern wontreturn void _thread_run(int(*func)(void*), void* arg);
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int cthread_create(cthread_t* restrict p, const cthread_attr_t* restrict attr,
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int (*func)(void*), void* restrict arg) {
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extern wontreturn void _thread_run(int (*func)(void*), void* arg);
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cthread_attr_t default_attr;
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cthread_attr_init(&default_attr);
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cthread_t td = _thread_allocate(attr ? attr : &default_attr);
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cthread_attr_destroy(&default_attr);
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if (!td) return errno;
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*p = td;
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register cthread_t td_ asm("r8") = td;
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register int* ptid_ asm("rdx") = &td->tid;
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register int* ctid_ asm("r10") = &td->tid;
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register int(*func_)(void*) asm("r12") = func;
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register int (*func_)(void*) asm("r12") = func;
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register void* arg_ asm("r13") = arg;
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long flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_PARENT | CLONE_THREAD | /*CLONE_IO |*/ CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID;
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long flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND |
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CLONE_PARENT | CLONE_THREAD | /*CLONE_IO |*/ CLONE_SETTLS |
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CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID;
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int rc;
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// asm ensures the (empty) stack of the child thread is not used
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asm volatile(
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"syscall\n\t" // clone
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"test\t%0, %0\n\t" // if not child
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"jne\t.L.cthread_create.%=\n\t" // jump to `parent` label
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"xor\t%%rbp, %%rbp\n\t" // reset stack frame pointer
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"mov\t%2, %%rdi\n\t"
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"call\t*%1\n\t" // call `func(arg)`
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"mov\t%%rax, %%rdi\n\t"
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"jmp\tcthread_exit\n" // exit thread
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".L.cthread_create.%=:"
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: "=a"(rc)
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: "r"(func_), "r"(arg_), "0"(__NR_clone), "D"(flags), "S"(td->stack.top), "r"(ptid_), "r"(ctid_), "r"(td_)
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: "rcx", "r11", "cc", "memory"
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);
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asm volatile("syscall\n\t" // clone
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"test\t%0, %0\n\t" // if not child
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"jne\t.L.cthread_create.%=\n\t" // jump to `parent` label
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"xor\t%%rbp, %%rbp\n\t" // reset stack frame pointer
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"mov\t%2, %%rdi\n\t"
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"call\t*%1\n\t" // call `func(arg)`
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"mov\t%%rax, %%rdi\n\t"
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"jmp\tcthread_exit\n" // exit thread
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".L.cthread_create.%=:"
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: "=a"(rc)
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: "r"(func_), "r"(arg_), "0"(__NR_clone), "D"(flags),
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"S"(td->stack.top), "r"(ptid_), "r"(ctid_), "r"(td_)
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: "rcx", "r11", "cc", "memory");
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if (__builtin_expect(rc < 0, 0)) {
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// `clone` has failed. The thread must be deallocated.
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size_t size = (intptr_t)(td->alloc.top) - (intptr_t)(td->alloc.bottom);
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