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 "hw/core/tcg-cpu-ops.h" 25 26 /* 27 * Stubbed out routines until we merge signal support from bsd-user 28 * fork. 29 */ 30 31 static struct target_sigaction sigact_table[TARGET_NSIG]; 32 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc); 33 34 /* 35 * The BSD ABIs use the same singal numbers across all the CPU architectures, so 36 * (unlike Linux) these functions are just the identity mapping. This might not 37 * be true for XyzBSD running on AbcBSD, which doesn't currently work. 38 */ 39 int host_to_target_signal(int sig) 40 { 41 return sig; 42 } 43 44 int target_to_host_signal(int sig) 45 { 46 return sig; 47 } 48 49 /* 50 * Queue a signal so that it will be send to the virtual CPU as soon as 51 * possible. 52 */ 53 void queue_signal(CPUArchState *env, int sig, target_siginfo_t *info) 54 { 55 qemu_log_mask(LOG_UNIMP, "No signal queueing, dropping signal %d\n", sig); 56 } 57 58 static int fatal_signal(int sig) 59 { 60 61 switch (sig) { 62 case TARGET_SIGCHLD: 63 case TARGET_SIGURG: 64 case TARGET_SIGWINCH: 65 case TARGET_SIGINFO: 66 /* Ignored by default. */ 67 return 0; 68 case TARGET_SIGCONT: 69 case TARGET_SIGSTOP: 70 case TARGET_SIGTSTP: 71 case TARGET_SIGTTIN: 72 case TARGET_SIGTTOU: 73 /* Job control signals. */ 74 return 0; 75 default: 76 return 1; 77 } 78 } 79 80 /* 81 * Force a synchronously taken QEMU_SI_FAULT signal. For QEMU the 82 * 'force' part is handled in process_pending_signals(). 83 */ 84 void force_sig_fault(int sig, int code, abi_ulong addr) 85 { 86 CPUState *cpu = thread_cpu; 87 CPUArchState *env = cpu->env_ptr; 88 target_siginfo_t info = {}; 89 90 info.si_signo = sig; 91 info.si_errno = 0; 92 info.si_code = code; 93 info.si_addr = addr; 94 queue_signal(env, sig, &info); 95 } 96 97 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc) 98 { 99 } 100 101 void signal_init(void) 102 { 103 TaskState *ts = (TaskState *)thread_cpu->opaque; 104 struct sigaction act; 105 struct sigaction oact; 106 int i; 107 int host_sig; 108 109 /* Set the signal mask from the host mask. */ 110 sigprocmask(0, 0, &ts->signal_mask); 111 112 sigfillset(&act.sa_mask); 113 act.sa_sigaction = host_signal_handler; 114 act.sa_flags = SA_SIGINFO; 115 116 for (i = 1; i <= TARGET_NSIG; i++) { 117 #ifdef CONFIG_GPROF 118 if (i == TARGET_SIGPROF) { 119 continue; 120 } 121 #endif 122 host_sig = target_to_host_signal(i); 123 sigaction(host_sig, NULL, &oact); 124 if (oact.sa_sigaction == (void *)SIG_IGN) { 125 sigact_table[i - 1]._sa_handler = TARGET_SIG_IGN; 126 } else if (oact.sa_sigaction == (void *)SIG_DFL) { 127 sigact_table[i - 1]._sa_handler = TARGET_SIG_DFL; 128 } 129 /* 130 * If there's already a handler installed then something has 131 * gone horribly wrong, so don't even try to handle that case. 132 * Install some handlers for our own use. We need at least 133 * SIGSEGV and SIGBUS, to detect exceptions. We can not just 134 * trap all signals because it affects syscall interrupt 135 * behavior. But do trap all default-fatal signals. 136 */ 137 if (fatal_signal(i)) { 138 sigaction(host_sig, &act, NULL); 139 } 140 } 141 } 142 143 void process_pending_signals(CPUArchState *cpu_env) 144 { 145 } 146 147 void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr, 148 MMUAccessType access_type, bool maperr, uintptr_t ra) 149 { 150 const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; 151 152 if (tcg_ops->record_sigsegv) { 153 tcg_ops->record_sigsegv(cpu, addr, access_type, maperr, ra); 154 } 155 156 force_sig_fault(TARGET_SIGSEGV, 157 maperr ? TARGET_SEGV_MAPERR : TARGET_SEGV_ACCERR, 158 addr); 159 cpu->exception_index = EXCP_INTERRUPT; 160 cpu_loop_exit_restore(cpu, ra); 161 } 162 163 void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr, 164 MMUAccessType access_type, uintptr_t ra) 165 { 166 const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops; 167 168 if (tcg_ops->record_sigbus) { 169 tcg_ops->record_sigbus(cpu, addr, access_type, ra); 170 } 171 172 force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr); 173 cpu->exception_index = EXCP_INTERRUPT; 174 cpu_loop_exit_restore(cpu, ra); 175 } 176