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authorLaurent Vivier <laurent@vivier.eu>2015-10-02 14:48:09 +0200
committerRiku Voipio <riku.voipio@linaro.org>2016-01-08 11:36:12 +0200
commite36800c91a74b656b4b4c74483863950cf9ec202 (patch)
treea4490654ca15328ea55eebd6d2f38eb29da443ef /linux-user
parent38a762fec63fd5c035aae29ba9a77d357e21e4a7 (diff)
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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 <sys/signalfd.h> #include <signal.h> #include <unistd.h> #include <stdlib.h> #include <stdio.h> #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 <laurent@vivier.eu> Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Diffstat (limited to 'linux-user')
-rw-r--r--linux-user/syscall.c167
1 files changed, 167 insertions, 0 deletions
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 6c64ba6..8fa8e0c 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 <sys/statfs.h>
#include <utime.h>
#include <sys/sysinfo.h>
+#include <sys/signalfd.h>
//#include <sys/user.h>
#include <netinet/ip.h>
#include <netinet/tcp.h>
@@ -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