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- /* -*- mode:c; c-file-style:"k&r"; c-basic-offset: 4; tab-width:4; indent-tabs-mode:nil; mode:auto-fill; fill-column:78; -*- */
- /* vim: set ts=4 sw=4 et tw=78 fo=cqt wm=0: */
- /* Copyright (C) 2014 Stony Brook University
- This file is part of Graphene Library OS.
- Graphene Library OS is free software: you can redistribute it and/or
- modify it under the terms of the GNU Lesser General Public License
- as published by the Free Software Foundation, either version 3 of the
- License, or (at your option) any later version.
- Graphene Library OS is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU Lesser General Public License for more details.
- You should have received a copy of the GNU Lesser General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
- /*
- * shim_signal.c
- *
- * This file contains codes to handle signals and exceptions passed from PAL.
- */
- #include <shim_internal.h>
- #include <shim_utils.h>
- #include <shim_table.h>
- #include <shim_thread.h>
- #include <shim_handle.h>
- #include <shim_vma.h>
- #include <shim_checkpoint.h>
- #include <shim_signal.h>
- #include <shim_unistd.h>
- #include <pal.h>
- static struct shim_signal **
- allocate_signal_log (struct shim_thread * thread, int sig)
- {
- if (!thread->signal_logs)
- return NULL;
- struct shim_signal_log * log = &thread->signal_logs[sig - 1];
- int head, tail, old_tail;
- do {
- head = atomic_read(&log->head);
- old_tail = tail = atomic_read(&log->tail);
- if (head == tail + 1 || (!head && tail == (MAX_SIGNAL_LOG - 1)))
- return NULL;
- tail = (tail == MAX_SIGNAL_LOG - 1) ? 0 : tail + 1;
- } while (atomic_cmpxchg(&log->tail, old_tail, tail) == tail);
- debug("signal_logs[%d]: head=%d, tail=%d\n", sig -1, head, tail);
- atomic_inc(&thread->has_signal);
- return &log->logs[old_tail];
- }
- static struct shim_signal *
- fetch_signal_log (shim_tcb_t * tcb, struct shim_thread * thread, int sig)
- {
- struct shim_signal_log * log = &thread->signal_logs[sig - 1];
- struct shim_signal * signal = NULL;
- int head, tail, old_head;
- while (1) {
- old_head = head = atomic_read(&log->head);
- tail = atomic_read(&log->tail);
- if (head == tail)
- return NULL;
- if (!(signal = log->logs[head]))
- return NULL;
- log->logs[head] = NULL;
- head = (head == MAX_SIGNAL_LOG - 1) ? 0 : head + 1;
- if (atomic_cmpxchg(&log->head, old_head, head) == old_head)
- break;
- log->logs[old_head] = signal;
- }
- debug("signal_logs[%d]: head=%d, tail=%d\n", sig -1, head, tail);
- atomic_dec(&thread->has_signal);
- return signal;
- }
- static void
- __handle_one_signal (shim_tcb_t * tcb, int sig, struct shim_signal * signal);
- static void __store_info (siginfo_t * info, struct shim_signal * signal)
- {
- if (info)
- memcpy(&signal->info, info, sizeof(siginfo_t));
- }
- void __store_context (shim_tcb_t * tcb, PAL_CONTEXT * pal_context,
- struct shim_signal * signal)
- {
- ucontext_t * context = &signal->context;
- if (tcb && tcb->context.syscall_nr) {
- struct shim_context * ct = &tcb->context;
- context->uc_mcontext.gregs[REG_RSP] = (unsigned long) ct->sp;
- context->uc_mcontext.gregs[REG_RIP] = (unsigned long) ct->ret_ip;
- if (ct->regs) {
- struct shim_regs * regs = ct->regs;
- context->uc_mcontext.gregs[REG_R15] = regs->r15;
- context->uc_mcontext.gregs[REG_R14] = regs->r14;
- context->uc_mcontext.gregs[REG_R13] = regs->r13;
- context->uc_mcontext.gregs[REG_R12] = regs->r12;
- context->uc_mcontext.gregs[REG_R11] = regs->r11;
- context->uc_mcontext.gregs[REG_R10] = regs->r10;
- context->uc_mcontext.gregs[REG_R9] = regs->r9;
- context->uc_mcontext.gregs[REG_R8] = regs->r8;
- context->uc_mcontext.gregs[REG_RCX] = regs->rcx;
- context->uc_mcontext.gregs[REG_RDX] = regs->rdx;
- context->uc_mcontext.gregs[REG_RSI] = regs->rsi;
- context->uc_mcontext.gregs[REG_RDI] = regs->rdi;
- context->uc_mcontext.gregs[REG_RBX] = regs->rbx;
- context->uc_mcontext.gregs[REG_RBP] = regs->rbp;
- }
- signal->context_stored = true;
- return;
- }
- if (pal_context) {
- memcpy(context->uc_mcontext.gregs, pal_context, sizeof(PAL_CONTEXT));
- signal->context_stored = true;
- }
- }
- void deliver_signal (siginfo_t * info, PAL_CONTEXT * context)
- {
- shim_tcb_t * tcb = SHIM_GET_TLS();
- if (!tcb || !tcb->tp)
- return;
- struct shim_thread * cur_thread = (struct shim_thread *) tcb->tp;
- int sig = info->si_signo;
- __disable_preempt(tcb);
- struct shim_signal * signal = __alloca(sizeof(struct shim_signal));
- /* save in signal */
- memset(signal, 0, sizeof(struct shim_signal));
- __store_info(info, signal);
- __store_context(tcb, context, signal);
- signal->pal_context = context;
- if ((tcb->context.preempt & ~SIGNAL_DELAYED) > 1)
- goto delay;
- if (__sigismember(&cur_thread->signal_mask, sig))
- goto delay;
- __handle_signal(tcb, sig, &signal->context);
- __handle_one_signal(tcb, sig, signal);
- goto out;
- delay:
- {
- if (!(signal = remalloc(signal,sizeof(struct shim_signal))))
- goto out;
- struct shim_signal ** signal_log = allocate_signal_log(cur_thread, sig);
- if (!signal_log) {
- sys_printf("signal queue is full (TID = %u, SIG = %d)\n",
- tcb->tid, sig);
- free(signal);
- goto out;
- }
- *signal_log = signal;
- }
- out:
- __enable_preempt(tcb);
- }
- #define ALLOC_SIGINFO(signo, code, member, value) \
- ({ \
- siginfo_t * _info = __alloca(sizeof(siginfo_t)); \
- memset(_info, 0, sizeof(siginfo_t)); \
- _info->si_signo = (signo); \
- _info->si_code = (code); \
- _info->member = (value); \
- _info; \
- })
- #ifdef __x86_64__
- #define IP rip
- #else
- #define IP eip
- #endif
- #define is_internal(context) \
- ((context) && \
- (void *) (context)->IP >= (void *) &__code_address && \
- (void *) (context)->IP < (void *) &__code_address_end)
- #define internal_fault(errstr, addr, context) \
- do { \
- IDTYPE tid = get_cur_tid(); \
- if (is_internal((context))) \
- sys_printf(errstr " at %p (IP = +0x%lx, VMID = %u, TID = %u)\n",\
- arg, \
- (void *) context->IP - (void *) &__load_address, \
- cur_process.vmid, IS_INTERNAL_TID(tid) ? 0 : tid); \
- else \
- sys_printf(errstr " at %p (IP = %p, VMID = %u, TID = %u)\n", \
- arg, context ? context->IP : 0, \
- cur_process.vmid, IS_INTERNAL_TID(tid) ? 0 : tid); \
- } while (0)
- static void divzero_upcall (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
- {
- if (IS_INTERNAL_TID(get_cur_tid()) || is_internal(context)) {
- internal_fault("Internal arithmetic fault", arg, context);
- pause();
- goto ret_exception;
- }
- if (context)
- debug("arithmetic fault at %p\n", context->IP);
- deliver_signal(ALLOC_SIGINFO(SIGFPE, FPE_INTDIV, si_addr, (void *) arg), context);
- ret_exception:
- DkExceptionReturn(event);
- }
- static void memfault_upcall (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
- {
- if (IS_INTERNAL_TID(get_cur_tid()) || is_internal(context)) {
- internal:
- internal_fault("Internal memory fault", arg, context);
- pause();
- goto ret_exception;
- }
- if (context)
- debug("memory fault at %p (IP = %p)\n", arg, context->IP);
- struct shim_vma * vma = NULL;
- int signo = SIGSEGV;
- int code;
- if (!arg) {
- code = SEGV_MAPERR;
- } else if (!lookup_supervma((void *) arg, 0, &vma)) {
- if (vma->flags & VMA_INTERNAL) {
- put_vma(vma);
- goto internal;
- }
- if (vma->file && vma->file->type == TYPE_FILE) {
- /* DEP 3/3/17: If the mapping exceeds end of a file (but is in the VMA)
- * then return a SIGBUS. */
- uint64_t eof_in_vma = (uint64_t) vma->addr + vma->offset + vma->file->info.file.size;
- if (arg > eof_in_vma) {
- signo = SIGBUS;
- code = BUS_ADRERR;
- } else if ((context->err & 4) && !(vma->flags & PROT_WRITE)) {
- /* DEP 3/3/17: If the page fault gives a write error, and
- * the VMA is read-only, return SIGSEGV+SEGV_ACCERR */
- signo = SIGSEGV;
- code = SEGV_ACCERR;
- } else {
- /* XXX: need more sophisticated judgement */
- signo = SIGBUS;
- code = BUS_ADRERR;
- }
- } else {
- code = SEGV_ACCERR;
- }
- put_vma(vma);
- } else {
- code = SEGV_MAPERR;
- }
- deliver_signal(ALLOC_SIGINFO(signo, code, si_addr, (void *) arg), context);
- ret_exception:
- DkExceptionReturn(event);
- }
- static void illegal_upcall (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
- {
- if (IS_INTERNAL_TID(get_cur_tid()) || is_internal(context)) {
- internal:
- internal_fault("Internal illegal fault", arg, context);
- pause();
- goto ret_exception;
- }
- struct shim_vma * vma = NULL;
- if (!(lookup_supervma((void *) arg, 0, &vma)) &&
- !(vma->flags & VMA_INTERNAL)) {
- if (context)
- debug("illegal instruction at %p\n", context->IP);
- if (vma)
- put_vma(vma);
- deliver_signal(ALLOC_SIGINFO(SIGILL, ILL_ILLOPC, si_addr, (void *) arg), context);
- } else {
- if (vma)
- put_vma(vma);
- goto internal;
- }
- ret_exception:
- DkExceptionReturn(event);
- }
- static void quit_upcall (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
- {
- if (IS_INTERNAL_TID(get_cur_tid()))
- goto ret_exception;
- deliver_signal(ALLOC_SIGINFO(SIGTERM, SI_USER, si_pid, 0), NULL);
- ret_exception:
- DkExceptionReturn(event);
- }
- static void suspend_upcall (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
- {
- if (IS_INTERNAL_TID(get_cur_tid()))
- goto ret_exception;
- deliver_signal(ALLOC_SIGINFO(SIGINT, SI_USER, si_pid, 0), NULL);
- ret_exception:
- DkExceptionReturn(event);
- }
- static void resume_upcall (PAL_PTR event, PAL_NUM arg, PAL_CONTEXT * context)
- {
- if (IS_INTERNAL_TID(get_cur_tid()))
- goto ret_exception;
- shim_tcb_t * tcb = SHIM_GET_TLS();
- if (!tcb || !tcb->tp)
- return;
- __disable_preempt(tcb);
- if ((tcb->context.preempt & ~SIGNAL_DELAYED) > 1) {
- tcb->context.preempt |= SIGNAL_DELAYED;
- __enable_preempt(tcb);
- goto ret_exception;
- }
- __handle_signal(tcb, 0, NULL);
- __enable_preempt(tcb);
- ret_exception:
- DkExceptionReturn(event);
- }
- int init_signal (void)
- {
- DkSetExceptionHandler(&divzero_upcall, PAL_EVENT_DIVZERO, 0);
- DkSetExceptionHandler(&memfault_upcall, PAL_EVENT_MEMFAULT, 0);
- DkSetExceptionHandler(&illegal_upcall, PAL_EVENT_ILLEGAL, 0);
- DkSetExceptionHandler(&quit_upcall, PAL_EVENT_QUIT, 0);
- DkSetExceptionHandler(&suspend_upcall, PAL_EVENT_SUSPEND, 0);
- DkSetExceptionHandler(&resume_upcall, PAL_EVENT_RESUME, 0);
- return 0;
- }
- __sigset_t * get_sig_mask (struct shim_thread * thread)
- {
- if (!thread)
- thread = get_cur_thread();
- assert(thread);
- return &(thread->signal_mask);
- }
- __sigset_t * set_sig_mask (struct shim_thread * thread,
- const __sigset_t * set)
- {
- if (!thread)
- thread = get_cur_thread();
- assert(thread);
- if (set)
- memcpy(&thread->signal_mask, set, sizeof(__sigset_t));
- return &thread->signal_mask;
- }
- static void (*default_sighandler[NUM_SIGS]) (int, siginfo_t *, void *);
- static void
- __handle_one_signal (shim_tcb_t * tcb, int sig, struct shim_signal * signal)
- {
- struct shim_thread * thread = (struct shim_thread *) tcb->tp;
- struct shim_signal_handle * sighdl = &thread->signal_handles[sig - 1];
- void (*handler) (int, siginfo_t *, void *) = NULL;
- if (signal->info.si_signo == SIGCP) {
- join_checkpoint(thread, &signal->context, si_cp_session(&signal->info));
- return;
- }
- debug("%s handled\n", signal_name(sig));
- lock(thread->lock);
- if (sighdl->action) {
- struct __kernel_sigaction * act = sighdl->action;
- /* This is a workaround. The truth is that many program will
- use sa_handler as sa_sigaction, because sa_sigaction is
- not supported in amd64 */
- #ifdef __i386__
- handler = (void (*) (int, siginfo_t *, void *)) act->_u._sa_handler;
- if (act->sa_flags & SA_SIGINFO)
- sa_handler = act->_u._sa_sigaction;
- #else
- handler = (void (*) (int, siginfo_t *, void *)) act->k_sa_handler;
- #endif
- if (act->sa_flags & SA_RESETHAND) {
- sighdl->action = NULL;
- free(act);
- }
- }
- unlock(thread->lock);
- if ((void *) handler == (void *) 1) /* SIG_IGN */
- return;
- if (!handler && !(handler = default_sighandler[sig - 1]))
- return;
- /* if the context is never stored in the signal, it means the
- signal is handled during system calls, and before the thread
- is resumed. */
- if (!signal->context_stored)
- __store_context(tcb, NULL, signal);
- struct shim_context * context = NULL;
- if (tcb->context.syscall_nr) {
- context = __alloca(sizeof(struct shim_context));
- memcpy(context, &tcb->context, sizeof(struct shim_context));
- tcb->context.syscall_nr = 0;
- tcb->context.next = context;
- }
- debug("run signal handler %p (%d, %p, %p)\n", handler, sig, &signal->info,
- &signal->context);
- (*handler) (sig, &signal->info, &signal->context);
- if (context)
- memcpy(&tcb->context, context, sizeof(struct shim_context));
- if (signal->pal_context)
- memcpy(signal->pal_context, signal->context.uc_mcontext.gregs,
- sizeof(PAL_CONTEXT));
- }
- void __handle_signal (shim_tcb_t * tcb, int sig, ucontext_t * uc)
- {
- struct shim_thread * thread = (struct shim_thread *) tcb->tp;
- int begin_sig = 1, end_sig = NUM_KNOWN_SIGS;
- if (sig)
- end_sig = (begin_sig = sig) + 1;
- sig = begin_sig;
- while (atomic_read(&thread->has_signal)) {
- struct shim_signal * signal = NULL;
- for ( ; sig < end_sig ; sig++)
- if (!__sigismember(&thread->signal_mask, sig) &&
- (signal = fetch_signal_log(tcb, thread, sig)))
- break;
- if (!signal)
- break;
- if (!signal->context_stored)
- __store_context(tcb, NULL, signal);
- __handle_one_signal(tcb, sig, signal);
- free(signal);
- DkThreadYieldExecution();
- tcb->context.preempt &= ~SIGNAL_DELAYED;
- }
- }
- void handle_signal (bool delayed_only)
- {
- shim_tcb_t * tcb = SHIM_GET_TLS();
- if (!tcb || !tcb->tp)
- return;
- struct shim_thread * thread = (struct shim_thread *) tcb->tp;
- /* Fast path */
- if (!thread->has_signal.counter)
- return;
- __disable_preempt(tcb);
- if ((tcb->context.preempt & ~SIGNAL_DELAYED) > 1) {
- tcb->context.preempt |= SIGNAL_DELAYED;
- goto out;
- }
- if (delayed_only && !(tcb->context.preempt & SIGNAL_DELAYED))
- goto out;
- __handle_signal(tcb, 0, NULL);
- out:
- __enable_preempt(tcb);
- }
- void append_signal (struct shim_thread * thread, int sig, siginfo_t * info,
- bool wakeup)
- {
- struct shim_signal * signal = malloc(sizeof(struct shim_signal));
- if (!signal)
- return;
- /* save in signal */
- if (info) {
- __store_info(info, signal);
- signal->context_stored = false;
- } else {
- memset(signal, 0, sizeof(struct shim_signal));
- }
- struct shim_signal ** signal_log = allocate_signal_log(thread, sig);
- if (signal_log) {
- *signal_log = signal;
- if (wakeup) {
- debug("resuming thread %u\n", thread->tid);
- DkThreadResume(thread->pal_handle);
- }
- } else {
- sys_printf("signal queue is full (TID = %u, SIG = %d)\n",
- thread->tid, sig);
- free(signal);
- }
- }
- static void sighandler_kill (int sig, siginfo_t * info, void * ucontext)
- {
- debug("killed by %s\n", signal_name(sig));
- if (!info->si_pid)
- switch(sig) {
- case SIGTERM:
- case SIGINT:
- shim_do_kill(-1, sig);
- break;
- }
- try_process_exit(0, sig);
- DkThreadExit();
- }
- /* We don't currently implement core dumps, but put a wrapper
- * in case we do in the future */
- static void sighandler_core (int sig, siginfo_t * info, void * ucontext)
- {
- sighandler_kill(sig, info, ucontext);
- }
- static void (*default_sighandler[NUM_SIGS]) (int, siginfo_t *, void *) =
- {
- /* SIGHUP */ &sighandler_kill,
- /* SIGINT */ &sighandler_kill,
- /* SIGQUIT */ &sighandler_kill,
- /* SIGILL */ &sighandler_kill,
- /* SIGTRAP */ &sighandler_core,
- /* SIGABRT */ &sighandler_kill,
- /* SIGBUS */ &sighandler_kill,
- /* SIGFPE */ &sighandler_kill,
- /* SIGKILL */ &sighandler_kill,
- /* SIGUSR1 */ NULL,
- /* SIGSEGV */ &sighandler_kill,
- /* SIGUSR2 */ NULL,
- /* SIGPIPE */ &sighandler_kill,
- /* SIGALRM */ &sighandler_kill,
- /* SIGTERM */ &sighandler_kill,
- /* SIGSTKFLT */ NULL,
- /* SIGCHLD */ NULL,
- /* SIGCONT */ NULL,
- /* SIGSTOP */ NULL,
- /* SIGTSTP */ NULL,
- /* SIGTTIN */ NULL,
- /* SIGTTOU */ NULL,
- };
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