From e36800c91a74b656b4b4c74483863950cf9ec202 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Fri, 2 Oct 2015 14:48:09 +0200 Subject: [PATCH] linux-user: add signalfd/signalfd4 syscalls This patch introduces a system very similar to the one used in the kernel to attach specific functions to a given file descriptor. In this case, we attach a specific "host_to_target()" translator to the fd returned by signalfd() to be able to byte-swap the signalfd_siginfo structure provided by read(). This patch allows to execute the example program given by man signalfd(2): #include #include #include #include #include #define handle_error(msg) \ do { perror(msg); exit(EXIT_FAILURE); } while (0) int main(int argc, char *argv[]) { sigset_t mask; int sfd; struct signalfd_siginfo fdsi; ssize_t s; sigemptyset(&mask); sigaddset(&mask, SIGINT); sigaddset(&mask, SIGQUIT); /* Block signals so that they aren't handled according to their default dispositions */ if (sigprocmask(SIG_BLOCK, &mask, NULL) == -1) handle_error("sigprocmask"); sfd = signalfd(-1, &mask, 0); if (sfd == -1) handle_error("signalfd"); for (;;) { s = read(sfd, &fdsi, sizeof(struct signalfd_siginfo)); if (s != sizeof(struct signalfd_siginfo)) handle_error("read"); if (fdsi.ssi_signo == SIGINT) { printf("Got SIGINT\n"); } else if (fdsi.ssi_signo == SIGQUIT) { printf("Got SIGQUIT\n"); exit(EXIT_SUCCESS); } else { printf("Read unexpected signal\n"); } } } $ ./signalfd_demo ^CGot SIGINT ^CGot SIGINT ^\Got SIGQUIT Signed-off-by: Laurent Vivier Signed-off-by: Riku Voipio --- linux-user/syscall.c | 167 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 6c64ba63db..8fa8e0ce14 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -60,6 +60,7 @@ int __clone2(int (*fn)(void *), void *child_stack_base, #include #include #include +#include //#include #include #include @@ -294,6 +295,54 @@ static bitmask_transtbl fcntl_flags_tbl[] = { { 0, 0, 0, 0 } }; +typedef abi_long (*TargetFdFunc)(void *, size_t); +typedef struct TargetFdTrans { + TargetFdFunc host_to_target; + TargetFdFunc target_to_host; +} TargetFdTrans; + +static TargetFdTrans **target_fd_trans; + +static unsigned int target_fd_max; + +static TargetFdFunc fd_trans_host_to_target(int fd) +{ + if (fd < target_fd_max && target_fd_trans[fd]) { + return target_fd_trans[fd]->host_to_target; + } + return NULL; +} + +static void fd_trans_register(int fd, TargetFdTrans *trans) +{ + unsigned int oldmax; + + if (fd >= target_fd_max) { + oldmax = target_fd_max; + target_fd_max = ((fd >> 6) + 1) << 6; /* by slice of 64 entries */ + target_fd_trans = g_realloc(target_fd_trans, + target_fd_max * sizeof(TargetFdTrans)); + memset((void *)(target_fd_trans + oldmax), 0, + (target_fd_max - oldmax) * sizeof(TargetFdTrans *)); + } + target_fd_trans[fd] = trans; +} + +static void fd_trans_unregister(int fd) +{ + if (fd >= 0 && fd < target_fd_max) { + target_fd_trans[fd] = NULL; + } +} + +static void fd_trans_dup(int oldfd, int newfd) +{ + fd_trans_unregister(newfd); + if (oldfd < target_fd_max && target_fd_trans[oldfd]) { + fd_trans_register(newfd, target_fd_trans[oldfd]); + } +} + static int sys_getcwd1(char *buf, size_t size) { if (getcwd(buf, size) == NULL) { @@ -5340,6 +5389,92 @@ static abi_long do_open_by_handle_at(abi_long mount_fd, abi_long handle, } #endif +#if defined(TARGET_NR_signalfd) || defined(TARGET_NR_signalfd4) + +/* signalfd siginfo conversion */ + +static void +host_to_target_signalfd_siginfo(struct signalfd_siginfo *tinfo, + const struct signalfd_siginfo *info) +{ + int sig = host_to_target_signal(info->ssi_signo); + + /* linux/signalfd.h defines a ssi_addr_lsb + * not defined in sys/signalfd.h but used by some kernels + */ + +#ifdef BUS_MCEERR_AO + if (tinfo->ssi_signo == SIGBUS && + (tinfo->ssi_code == BUS_MCEERR_AR || + tinfo->ssi_code == BUS_MCEERR_AO)) { + uint16_t *ssi_addr_lsb = (uint16_t *)(&info->ssi_addr + 1); + uint16_t *tssi_addr_lsb = (uint16_t *)(&tinfo->ssi_addr + 1); + *tssi_addr_lsb = tswap16(*ssi_addr_lsb); + } +#endif + + tinfo->ssi_signo = tswap32(sig); + tinfo->ssi_errno = tswap32(tinfo->ssi_errno); + tinfo->ssi_code = tswap32(info->ssi_code); + tinfo->ssi_pid = tswap32(info->ssi_pid); + tinfo->ssi_uid = tswap32(info->ssi_uid); + tinfo->ssi_fd = tswap32(info->ssi_fd); + tinfo->ssi_tid = tswap32(info->ssi_tid); + tinfo->ssi_band = tswap32(info->ssi_band); + tinfo->ssi_overrun = tswap32(info->ssi_overrun); + tinfo->ssi_trapno = tswap32(info->ssi_trapno); + tinfo->ssi_status = tswap32(info->ssi_status); + tinfo->ssi_int = tswap32(info->ssi_int); + tinfo->ssi_ptr = tswap64(info->ssi_ptr); + tinfo->ssi_utime = tswap64(info->ssi_utime); + tinfo->ssi_stime = tswap64(info->ssi_stime); + tinfo->ssi_addr = tswap64(info->ssi_addr); +} + +static abi_long host_to_target_signalfd(void *buf, size_t len) +{ + int i; + + for (i = 0; i < len; i += sizeof(struct signalfd_siginfo)) { + host_to_target_signalfd_siginfo(buf + i, buf + i); + } + + return len; +} + +static TargetFdTrans target_signalfd_trans = { + .host_to_target = host_to_target_signalfd, +}; + +static abi_long do_signalfd4(int fd, abi_long mask, int flags) +{ + int host_flags; + target_sigset_t *target_mask; + sigset_t host_mask; + abi_long ret; + + if (flags & ~(TARGET_O_NONBLOCK | TARGET_O_CLOEXEC)) { + return -TARGET_EINVAL; + } + if (!lock_user_struct(VERIFY_READ, target_mask, mask, 1)) { + return -TARGET_EFAULT; + } + + target_to_host_sigset(&host_mask, target_mask); + + host_flags = target_to_host_bitmask(flags, fcntl_flags_tbl); + + ret = get_errno(signalfd(fd, &host_mask, host_flags)); + if (ret >= 0) { + fd_trans_register(ret, &target_signalfd_trans); + } + + unlock_user_struct(target_mask, mask, 0); + + return ret; +} +#endif + /* Map host to target signal numbers for the wait family of syscalls. Assume all other status bits are the same. */ int host_to_target_waitstatus(int status) @@ -5724,6 +5859,10 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, if (!(p = lock_user(VERIFY_WRITE, arg2, arg3, 0))) goto efault; ret = get_errno(read(arg1, p, arg3)); + if (ret >= 0 && + fd_trans_host_to_target(arg1)) { + ret = fd_trans_host_to_target(arg1)(p, ret); + } unlock_user(p, arg2, ret); } break; @@ -5740,6 +5879,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, ret = get_errno(do_openat(cpu_env, AT_FDCWD, p, target_to_host_bitmask(arg2, fcntl_flags_tbl), arg3)); + fd_trans_unregister(ret); unlock_user(p, arg1, 0); break; #endif @@ -5749,6 +5889,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, ret = get_errno(do_openat(cpu_env, arg1, p, target_to_host_bitmask(arg3, fcntl_flags_tbl), arg4)); + fd_trans_unregister(ret); unlock_user(p, arg2, 0); break; #if defined(TARGET_NR_name_to_handle_at) && defined(CONFIG_OPEN_BY_HANDLE) @@ -5759,9 +5900,11 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #if defined(TARGET_NR_open_by_handle_at) && defined(CONFIG_OPEN_BY_HANDLE) case TARGET_NR_open_by_handle_at: ret = do_open_by_handle_at(arg1, arg2, arg3); + fd_trans_unregister(ret); break; #endif case TARGET_NR_close: + fd_trans_unregister(arg1); ret = get_errno(close(arg1)); break; case TARGET_NR_brk: @@ -5803,6 +5946,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, if (!(p = lock_user_string(arg1))) goto efault; ret = get_errno(creat(p, arg2)); + fd_trans_unregister(ret); unlock_user(p, arg1, 0); break; #endif @@ -6250,6 +6394,9 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #endif case TARGET_NR_dup: ret = get_errno(dup(arg1)); + if (ret >= 0) { + fd_trans_dup(arg1, ret); + } break; #ifdef TARGET_NR_pipe case TARGET_NR_pipe: @@ -6347,11 +6494,17 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #ifdef TARGET_NR_dup2 case TARGET_NR_dup2: ret = get_errno(dup2(arg1, arg2)); + if (ret >= 0) { + fd_trans_dup(arg1, arg2); + } break; #endif #if defined(CONFIG_DUP3) && defined(TARGET_NR_dup3) case TARGET_NR_dup3: ret = get_errno(dup3(arg1, arg2, arg3)); + if (ret >= 0) { + fd_trans_dup(arg1, arg2); + } break; #endif #ifdef TARGET_NR_getppid /* not on alpha */ @@ -7347,6 +7500,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #ifdef TARGET_NR_socket case TARGET_NR_socket: ret = do_socket(arg1, arg2, arg3); + fd_trans_unregister(ret); break; #endif #ifdef TARGET_NR_socketpair @@ -9600,6 +9754,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, #if defined(TARGET_NR_eventfd) case TARGET_NR_eventfd: ret = get_errno(eventfd(arg1, 0)); + fd_trans_unregister(ret); break; #endif #if defined(TARGET_NR_eventfd2) @@ -9613,6 +9768,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, host_flags |= O_CLOEXEC; } ret = get_errno(eventfd(arg1, host_flags)); + fd_trans_unregister(ret); break; } #endif @@ -9655,6 +9811,16 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, break; #endif #endif +#if defined(TARGET_NR_signalfd4) + case TARGET_NR_signalfd4: + ret = do_signalfd4(arg1, arg2, arg4); + break; +#endif +#if defined(TARGET_NR_signalfd) + case TARGET_NR_signalfd: + ret = do_signalfd4(arg1, arg2, 0); + break; +#endif #if defined(CONFIG_EPOLL) #if defined(TARGET_NR_epoll_create) case TARGET_NR_epoll_create: @@ -9926,6 +10092,7 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, timer_t htimer = g_posix_timers[timerid]; ret = get_errno(timer_getoverrun(htimer)); } + fd_trans_unregister(ret); break; } #endif