1 /* 2 * Emulation of BSD signals 3 * 4 * Copyright (c) 2003 - 2008 Fabrice Bellard 5 * Copyright (c) 2013 Stacey Son 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include "qemu/osdep.h" 22 #include "qemu.h" 23 #include "signal-common.h" 24 #include "trace.h" 25 #include "hw/core/tcg-cpu-ops.h" 26 #include "host-signal.h" 27 28 /* 29 * Stubbed out routines until we merge signal support from bsd-user 30 * fork. 31 */ 32 33 static struct target_sigaction sigact_table[TARGET_NSIG]; 34 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc); 35 36 /* 37 * The BSD ABIs use the same singal numbers across all the CPU architectures, so 38 * (unlike Linux) these functions are just the identity mapping. This might not 39 * be true for XyzBSD running on AbcBSD, which doesn't currently work. 40 */ 41 int host_to_target_signal(int sig) 42 { 43 return sig; 44 } 45 46 int target_to_host_signal(int sig) 47 { 48 return sig; 49 } 50 51 /* 52 * Queue a signal so that it will be send to the virtual CPU as soon as 53 * possible. 54 */ 55 void queue_signal(CPUArchState *env, int sig, int si_type, 56 target_siginfo_t *info) 57 { 58 qemu_log_mask(LOG_UNIMP, "No signal queueing, dropping signal %d\n", sig); 59 } 60 61 static int fatal_signal(int sig) 62 { 63 64 switch (sig) { 65 case TARGET_SIGCHLD: 66 case TARGET_SIGURG: 67 case TARGET_SIGWINCH: 68 case TARGET_SIGINFO: 69 /* Ignored by default. */ 70 return 0; 71 case TARGET_SIGCONT: 72 case TARGET_SIGSTOP: 73 case TARGET_SIGTSTP: 74 case TARGET_SIGTTIN: 75 case TARGET_SIGTTOU: 76 /* Job control signals. */ 77 return 0; 78 default: 79 return 1; 80 } 81 } 82 83 /* 84 * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the 85 * 'force' part is handled in process_pending_signals(). 86 */ 87 void force_sig_fault(int sig, int code, abi_ulong addr) 88 { 89 CPUState *cpu = thread_cpu; 90 CPUArchState *env = cpu->env_ptr; 91 target_siginfo_t info = {}; 92 93 info.si_signo = sig; 94 info.si_errno = 0; 95 info.si_code = code; 96 info.si_addr = addr; 97 queue_signal(env, sig, QEMU_SI_FAULT, &info); 98 } 99 100 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) 101 { 102 } 103 104 void signal_init(void) 105 { 106 TaskState *ts = (TaskState *)thread_cpu->opaque; 107 struct sigaction act; 108 struct sigaction oact; 109 int i; 110 int host_sig; 111 112 /* Set the signal mask from the host mask. */ 113 sigprocmask(0, 0, &ts->signal_mask); 114 115 sigfillset(&act.sa_mask); 116 act.sa_sigaction = host_signal_handler; 117 act.sa_flags = SA_SIGINFO; 118 119 for (i = 1; i <= TARGET_NSIG; i++) { 120 #ifdef CONFIG_GPROF 121 if (i == TARGET_SIGPROF) { 122 continue; 123 } 124 #endif 125 host_sig = target_to_host_signal(i); 126 sigaction(host_sig, NULL, &oact); 127 if (oact.sa_sigaction == (void *)SIG_IGN) { 128 sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN; 129 } else if (oact.sa_sigaction == (void *)SIG_DFL) { 130 sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL; 131 } 132 /* 133 * If there's already a handler installed then something has 134 * gone horribly wrong, so don't even try to handle that case. 135 * Install some handlers for our own use. We need at least 136 * SIGSEGV and SIGBUS, to detect exceptions. We can not just 137 * trap all signals because it affects syscall interrupt 138 * behavior. But do trap all default-fatal signals. 139 */ 140 if (fatal_signal(i)) { 141 sigaction(host_sig, &act, NULL); 142 } 143 } 144 } 145 146 void process_pending_signals(CPUArchState *cpu_env) 147 { 148 } 149 150 void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr, 151 MMUAccessType access_type, bool maperr, uintptr_t ra) 152 { 153 const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; 154 155 if (tcg_ops->record_sigsegv) { 156 tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra); 157 } 158 159 force_sig_fault(TARGET_SIGSEGV, 160 maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR, 161 addr); 162 cpu->exception_index = EXCP_INTERRUPT; 163 cpu_loop_exit_restore(cpu, ra); 164 } 165 166 void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr, 167 MMUAccessType access_type, uintptr_t ra) 168 { 169 const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; 170 171 if (tcg_ops->record_sigbus) { 172 tcg_ops->record_sigbus(cpu, addr, access_type, ra); 173 } 174 175 force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); 176 cpu->exception_index = EXCP_INTERRUPT; 177 cpu_loop_exit_restore(cpu, ra); 178 } 179