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-rw-r--r--src/env/__init_tls.c55
-rw-r--r--src/env/__stack_chk_fail.c8
-rw-r--r--src/errno/__errno_location.c2
-rw-r--r--src/internal/libc.h4
-rw-r--r--src/ldso/dynlink.c28
-rw-r--r--src/process/fork.c5
-rw-r--r--src/signal/sigaction.c19
-rw-r--r--src/stdio/__stdio_read.c10
-rw-r--r--src/stdio/__stdio_write.c10
-rw-r--r--src/thread/cancel_impl.c3
-rw-r--r--src/thread/pthread_create.c11
-rw-r--r--src/thread/pthread_key_create.c8
-rw-r--r--src/thread/pthread_self.c41
-rw-r--r--src/thread/pthread_setcancelstate.c12
14 files changed, 118 insertions, 98 deletions
diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c
index dbfe62e7..8ac0036b 100644
--- a/src/env/__init_tls.c
+++ b/src/env/__init_tls.c
@@ -7,8 +7,28 @@
#include "atomic.h"
#include "syscall.h"
+int __init_tp(void *p)
+{
+ pthread_t td = p;
+ td->self = td;
+ if (__set_thread_area(TP_ADJ(p)) < 0)
+ return -1;
+ td->tid = td->pid = __syscall(SYS_set_tid_address, &td->tid);
+ td->errno_ptr = &td->errno_val;
+ /* Currently, both of these predicates depend in the same thing:
+ * successful initialization of the thread pointer. However, in
+ * the future, we may support setups where setting the thread
+ * pointer is possible but threads other than the main thread
+ * cannot work, so it's best to keep the predicates separate. */
+ libc.has_thread_pointer = 1;
+ libc.can_do_threads = 1;
+ return 0;
+}
+
#ifndef SHARED
+static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
+
struct tls_image {
void *image;
size_t len, size, align;
@@ -62,10 +82,11 @@ typedef Elf64_Phdr Phdr;
void __init_tls(size_t *aux)
{
- unsigned char *p, *mem;
+ unsigned char *p;
size_t n;
Phdr *phdr, *tls_phdr=0;
size_t base = 0;
+ void *mem;
libc.tls_size = sizeof(struct pthread);
@@ -76,28 +97,38 @@ void __init_tls(size_t *aux)
if (phdr->p_type == PT_TLS)
tls_phdr = phdr;
}
- if (!tls_phdr) return;
- T.image = (void *)(base + tls_phdr->p_vaddr);
- T.len = tls_phdr->p_filesz;
- T.size = tls_phdr->p_memsz;
- T.align = tls_phdr->p_align;
+ if (tls_phdr) {
+ T.image = (void *)(base + tls_phdr->p_vaddr);
+ T.len = tls_phdr->p_filesz;
+ T.size = tls_phdr->p_memsz;
+ T.align = tls_phdr->p_align;
+ }
T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
if (T.align < 4*sizeof(size_t)) T.align = 4*sizeof(size_t);
libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
- mem = (void *)__syscall(
+ if (libc.tls_size > sizeof builtin_tls) {
+ mem = (void *)__syscall(
#ifdef SYS_mmap2
- SYS_mmap2,
+ SYS_mmap2,
#else
- SYS_mmap,
+ SYS_mmap,
#endif
- 0, libc.tls_size, PROT_READ|PROT_WRITE,
- MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+ 0, libc.tls_size, PROT_READ|PROT_WRITE,
+ MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+ /* -4095...-1 cast to void * will crash on dereference anyway,
+ * so don't bloat the init code checking for error codes and
+ * explicitly calling a_crash(). */
+ } else {
+ mem = builtin_tls;
+ }
- if (!__install_initial_tls(__copy_tls(mem))) a_crash();
+ /* Failure to initialize thread pointer is fatal if TLS is used. */
+ if (__init_tp(__copy_tls(mem)) < 0 && tls_phdr)
+ a_crash();
}
#else
void __init_tls(size_t *auxv) { }
diff --git a/src/env/__stack_chk_fail.c b/src/env/__stack_chk_fail.c
index daa1b078..00634d38 100644
--- a/src/env/__stack_chk_fail.c
+++ b/src/env/__stack_chk_fail.c
@@ -7,7 +7,13 @@ uintptr_t __stack_chk_guard;
void __init_ssp(void *entropy)
{
- pthread_t self = __pthread_self_init();
+ /* Here the thread pointer is used without checking whether
+ * it is available; this will crash if it's not. However,
+ * this function is only meant to be called if the program
+ * being run uses stack protector, and in that case, it would
+ * crash without a thread pointer anyway, so it's better to
+ * crash early before there is state to be lost on crash. */
+ pthread_t self = __pthread_self();
uintptr_t canary;
if (entropy) memcpy(&canary, entropy, sizeof canary);
else canary = (uintptr_t)&canary * 1103515245;
diff --git a/src/errno/__errno_location.c b/src/errno/__errno_location.c
index 3e92d7c7..84191076 100644
--- a/src/errno/__errno_location.c
+++ b/src/errno/__errno_location.c
@@ -3,6 +3,6 @@
int *__errno_location(void)
{
static int e;
- if (libc.main_thread) return __pthread_self()->errno_ptr;
+ if (libc.has_thread_pointer) return __pthread_self()->errno_ptr;
return &e;
}
diff --git a/src/internal/libc.h b/src/internal/libc.h
index d625b56a..fb4d9bc0 100644
--- a/src/internal/libc.h
+++ b/src/internal/libc.h
@@ -6,12 +6,12 @@
#include <limits.h>
struct __libc {
- void *main_thread;
+ int has_thread_pointer;
+ int can_do_threads;
int threaded;
int secure;
size_t *auxv;
volatile int threads_minus_1;
- int canceldisable;
FILE *ofl_head;
int ofl_lock[2];
size_t tls_size;
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index a1bdf0fb..616dc3e1 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -90,7 +90,7 @@ struct symdef {
#include "reloc.h"
void __init_ssp(size_t *);
-void *__install_initial_tls(void *);
+int __init_tp(void *);
void __init_libc(char **, char *);
const char *__libc_get_version(void);
@@ -108,6 +108,7 @@ static pthread_rwlock_t lock;
static struct debug debug;
static size_t tls_cnt, tls_offset, tls_align = 4*sizeof(size_t);
static pthread_mutex_t init_fini_lock = { ._m_type = PTHREAD_MUTEX_RECURSIVE };
+static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
struct debug *_dl_debug_addr = &debug;
@@ -673,9 +674,10 @@ static struct dso *load_library(const char *name, struct dso *needed_by)
/* Add a shortname only if name arg was not an explicit pathname. */
if (pathname != name) p->shortname = strrchr(p->name, '/')+1;
if (p->tls_image) {
- if (runtime && !__pthread_self_init()) {
+ if (runtime && !libc.has_thread_pointer) {
munmap(map, p->map_len);
free(p);
+ errno = ENOSYS;
return 0;
}
p->tls_id = ++tls_cnt;
@@ -866,10 +868,13 @@ void *__copy_tls(unsigned char *mem)
pthread_t td;
struct dso *p;
- if (!tls_cnt) return mem;
-
void **dtv = (void *)mem;
dtv[0] = (void *)tls_cnt;
+ if (!tls_cnt) {
+ td = (void *)(dtv+1);
+ td->dtv = dtv;
+ return td;
+ }
#ifdef TLS_ABOVE_TP
mem += sizeof(void *) * (tls_cnt+1);
@@ -962,6 +967,7 @@ void *__dynlink(int argc, char **argv)
size_t vdso_base;
size_t *auxv;
char **envp = argv+argc+1;
+ void *initial_tls;
/* Find aux vector just past environ[] */
for (i=argc+1; argv[i]; i++)
@@ -1144,15 +1150,19 @@ void *__dynlink(int argc, char **argv)
reloc_all(app);
update_tls_size();
- if (tls_cnt) {
- void *mem = mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
- MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
- if (mem==MAP_FAILED ||
- !__install_initial_tls(__copy_tls(mem))) {
+ if (libc.tls_size > sizeof builtin_tls) {
+ initial_tls = calloc(libc.tls_size, 1);
+ if (!initial_tls) {
dprintf(2, "%s: Error getting %zu bytes thread-local storage: %m\n",
argv[0], libc.tls_size);
_exit(127);
}
+ } else {
+ initial_tls = builtin_tls;
+ }
+ if (__init_tp(__copy_tls(initial_tls)) < 0 && tls_cnt) {
+ dprintf(2, "%s: Thread-local storage not supported by kernel.\n", argv[0]);
+ _exit(127);
}
if (ldso_fail) _exit(127);
diff --git a/src/process/fork.c b/src/process/fork.c
index 1a82f428..864c7d7a 100644
--- a/src/process/fork.c
+++ b/src/process/fork.c
@@ -17,12 +17,11 @@ pid_t fork(void)
__fork_handler(-1);
__block_all_sigs(&set);
ret = syscall(SYS_fork);
- if (libc.main_thread && !ret) {
+ if (libc.has_thread_pointer && !ret) {
pthread_t self = __pthread_self();
- self->tid = self->pid = syscall(SYS_getpid);
+ self->tid = self->pid = __syscall(SYS_getpid);
memset(&self->robust_list, 0, sizeof self->robust_list);
libc.threads_minus_1 = 0;
- libc.main_thread = self;
}
__restore_sigs(&set);
__fork_handler(!ret);
diff --git a/src/signal/sigaction.c b/src/signal/sigaction.c
index f7ff4a61..d5f47741 100644
--- a/src/signal/sigaction.c
+++ b/src/signal/sigaction.c
@@ -8,9 +8,7 @@
void __restore(), __restore_rt();
-static pthread_t dummy(void) { return 0; }
-weak_alias(dummy, __pthread_self_def);
-
+static int unmask_done;
static unsigned long handler_set[_NSIG/(8*sizeof(long))];
void __get_handler_set(sigset_t *set)
@@ -29,7 +27,20 @@ int __libc_sigaction(int sig, const struct sigaction *restrict sa, struct sigact
if ((uintptr_t)sa->sa_handler > 1UL) {
a_or_l(handler_set+(sig-1)/(8*sizeof(long)),
1UL<<(sig-1)%(8*sizeof(long)));
- __pthread_self_def();
+
+ /* If pthread_create has not yet been called,
+ * implementation-internal signals might not
+ * yet have been unblocked. They must be
+ * unblocked before any signal handler is
+ * installed, so that an application cannot
+ * receive an illegal sigset_t (with them
+ * blocked) as part of the ucontext_t passed
+ * to the signal handler. */
+ if (!libc.threaded && !unmask_done) {
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
+ SIGPT_SET, 0, _NSIG/8);
+ unmask_done = 1;
+ }
}
ksa.handler = sa->sa_handler;
ksa.flags = sa->sa_flags | SA_RESTORER;
diff --git a/src/stdio/__stdio_read.c b/src/stdio/__stdio_read.c
index 05e56f92..6cd7b073 100644
--- a/src/stdio/__stdio_read.c
+++ b/src/stdio/__stdio_read.c
@@ -16,13 +16,9 @@ size_t __stdio_read(FILE *f, unsigned char *buf, size_t len)
};
ssize_t cnt;
- if (libc.main_thread) {
- pthread_cleanup_push(cleanup, f);
- cnt = syscall_cp(SYS_readv, f->fd, iov, 2);
- pthread_cleanup_pop(0);
- } else {
- cnt = syscall(SYS_readv, f->fd, iov, 2);
- }
+ pthread_cleanup_push(cleanup, f);
+ cnt = syscall_cp(SYS_readv, f->fd, iov, 2);
+ pthread_cleanup_pop(0);
if (cnt <= 0) {
f->flags |= F_EOF ^ ((F_ERR^F_EOF) & cnt);
f->rpos = f->rend = 0;
diff --git a/src/stdio/__stdio_write.c b/src/stdio/__stdio_write.c
index e52e91ae..8c89389a 100644
--- a/src/stdio/__stdio_write.c
+++ b/src/stdio/__stdio_write.c
@@ -19,13 +19,9 @@ size_t __stdio_write(FILE *f, const unsigned char *buf, size_t len)
int iovcnt = 2;
ssize_t cnt;
for (;;) {
- if (libc.main_thread) {
- pthread_cleanup_push(cleanup, f);
- cnt = syscall_cp(SYS_writev, f->fd, iov, iovcnt);
- pthread_cleanup_pop(0);
- } else {
- cnt = syscall(SYS_writev, f->fd, iov, iovcnt);
- }
+ pthread_cleanup_push(cleanup, f);
+ cnt = syscall_cp(SYS_writev, f->fd, iov, iovcnt);
+ pthread_cleanup_pop(0);
if (cnt == rem) {
f->wend = f->buf + f->buf_size;
f->wpos = f->wbase = f->buf;
diff --git a/src/thread/cancel_impl.c b/src/thread/cancel_impl.c
index c835813a..525d2904 100644
--- a/src/thread/cancel_impl.c
+++ b/src/thread/cancel_impl.c
@@ -20,7 +20,7 @@ long (__syscall_cp)(syscall_arg_t nr,
pthread_t self;
long r;
- if (!libc.main_thread || (self = __pthread_self())->canceldisable)
+ if (!libc.has_thread_pointer || (self = __pthread_self())->canceldisable)
return __syscall(nr, u, v, w, x, y, z);
r = __syscall_cp_asm(&self->cancel, nr, u, v, w, x, y, z);
@@ -57,6 +57,7 @@ static void cancel_handler(int sig, siginfo_t *si, void *ctx)
void __testcancel()
{
+ if (!libc.has_thread_pointer) return;
pthread_t self = pthread_self();
if (self->cancel && !self->canceldisable)
__cancel();
diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index ee6c31c4..08c74110 100644
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -77,6 +77,7 @@ _Noreturn void pthread_exit(void *result)
void __do_cleanup_push(struct __ptcb *cb)
{
+ if (!libc.has_thread_pointer) return;
struct pthread *self = pthread_self();
cb->__next = self->cancelbuf;
self->cancelbuf = cb;
@@ -84,6 +85,7 @@ void __do_cleanup_push(struct __ptcb *cb)
void __do_cleanup_pop(struct __ptcb *cb)
{
+ if (!libc.has_thread_pointer) return;
__pthread_self()->cancelbuf = cb->__next;
}
@@ -110,6 +112,8 @@ static int start(void *p)
/* pthread_key_create.c overrides this */
static const size_t dummy = 0;
weak_alias(dummy, __pthread_tsd_size);
+static const void *dummy_tsd[1] = { 0 };
+weak_alias(dummy_tsd, __pthread_tsd_main);
static FILE *const dummy_file = 0;
weak_alias(dummy_file, __stdin_used);
@@ -127,7 +131,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
{
int ret;
size_t size, guard;
- struct pthread *self = pthread_self(), *new;
+ struct pthread *self, *new;
unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
unsigned flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND
| CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS
@@ -135,13 +139,16 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
int do_sched = 0;
pthread_attr_t attr = {0};
- if (!self) return ENOSYS;
+ if (!libc.can_do_threads) return ENOSYS;
+ self = __pthread_self();
if (!libc.threaded) {
for (FILE *f=libc.ofl_head; f; f=f->next)
init_file_lock(f);
init_file_lock(__stdin_used);
init_file_lock(__stdout_used);
init_file_lock(__stderr_used);
+ __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK, SIGPT_SET, 0, _NSIG/8);
+ self->tsd = __pthread_tsd_main;
libc.threaded = 1;
}
if (attrp) attr = *attrp;
diff --git a/src/thread/pthread_key_create.c b/src/thread/pthread_key_create.c
index c29935c1..ef8a755d 100644
--- a/src/thread/pthread_key_create.c
+++ b/src/thread/pthread_key_create.c
@@ -14,7 +14,13 @@ int pthread_key_create(pthread_key_t *k, void (*dtor)(void *))
unsigned i = (uintptr_t)&k / 16 % PTHREAD_KEYS_MAX;
unsigned j = i;
- __pthread_self_init();
+ if (libc.has_thread_pointer) {
+ pthread_t self = __pthread_self();
+ /* This can only happen in the main thread before
+ * pthread_create has been called. */
+ if (!self->tsd) self->tsd = __pthread_tsd_main;
+ }
+
if (!dtor) dtor = nodtor;
do {
if (!a_cas_p(keys+j, 0, (void *)dtor)) {
diff --git a/src/thread/pthread_self.c b/src/thread/pthread_self.c
index aed4b5f1..5f9e6516 100644
--- a/src/thread/pthread_self.c
+++ b/src/thread/pthread_self.c
@@ -1,45 +1,6 @@
#include "pthread_impl.h"
-static struct pthread *main_thread = &(struct pthread){0};
-
-/* pthread_key_create.c overrides this */
-static const void *dummy[1] = { 0 };
-weak_alias(dummy, __pthread_tsd_main);
-
-static int init_main_thread()
-{
- __syscall(SYS_rt_sigprocmask, SIG_UNBLOCK,
- SIGPT_SET, 0, _NSIG/8);
- if (__set_thread_area(TP_ADJ(main_thread)) < 0) return -1;
- main_thread->canceldisable = libc.canceldisable;
- main_thread->tsd = (void **)__pthread_tsd_main;
- main_thread->errno_ptr = __errno_location();
- main_thread->self = main_thread;
- main_thread->tid = main_thread->pid =
- __syscall(SYS_set_tid_address, &main_thread->tid);
- if (!main_thread->dtv)
- main_thread->dtv = (void *)dummy;
- libc.main_thread = main_thread;
- return 0;
-}
-
-pthread_t __pthread_self_def()
+pthread_t pthread_self()
{
- static int init, failed;
- if (!init) {
- if (failed) return 0;
- if (init_main_thread() < 0) failed = 1;
- if (failed) return 0;
- init = 1;
- }
return __pthread_self();
}
-
-weak_alias(__pthread_self_def, pthread_self);
-weak_alias(__pthread_self_def, __pthread_self_init);
-
-void *__install_initial_tls(void *p)
-{
- main_thread = p;
- return __pthread_self_def();
-}
diff --git a/src/thread/pthread_setcancelstate.c b/src/thread/pthread_setcancelstate.c
index ba2b2311..060bcdcc 100644
--- a/src/thread/pthread_setcancelstate.c
+++ b/src/thread/pthread_setcancelstate.c
@@ -3,13 +3,9 @@
int pthread_setcancelstate(int new, int *old)
{
if (new > 1U) return EINVAL;
- if (libc.main_thread) {
- struct pthread *self = __pthread_self();
- if (old) *old = self->canceldisable;
- self->canceldisable = new;
- } else {
- if (old) *old = libc.canceldisable;
- libc.canceldisable = new;
- }
+ if (!libc.has_thread_pointer) return ENOSYS;
+ struct pthread *self = __pthread_self();
+ if (old) *old = self->canceldisable;
+ self->canceldisable = new;
return 0;
}
generated by cgit v1.2.1 (git 2.18.0) at 2025-11-04 00:41:14 +0000