diff options
Diffstat (limited to 'libc/sysdeps/linux/x86_64/sigaction.c')
| -rw-r--r-- | libc/sysdeps/linux/x86_64/sigaction.c | 113 |
1 files changed, 51 insertions, 62 deletions
diff --git a/libc/sysdeps/linux/x86_64/sigaction.c b/libc/sysdeps/linux/x86_64/sigaction.c index aa5c0d472..a4042a9c8 100644 --- a/libc/sysdeps/linux/x86_64/sigaction.c +++ b/libc/sysdeps/linux/x86_64/sigaction.c @@ -13,9 +13,8 @@ Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library; if not, write to the Free - Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA - 02111-1307 USA. */ + License along with the GNU C Library; if not, see + <http://www.gnu.org/licenses/>. */ #include <errno.h> @@ -25,90 +24,64 @@ #include <sys/syscall.h> -/* The difference here is that the sigaction structure used in the - kernel is not the same as we use in the libc. Therefore we must - translate it here. */ #include <bits/kernel_sigaction.h> /* We do not globally define the SA_RESTORER flag so do it here. */ #define SA_RESTORER 0x04000000 -extern __typeof(sigaction) __libc_sigaction; - #ifdef __NR_rt_sigaction + /* Using the hidden attribute here does not change the code but it helps to avoid warnings. */ -extern void restore_rt (void) __asm__ ("__restore_rt") attribute_hidden; -extern void restore (void) __asm__ ("__restore") attribute_hidden; - -/* Experimentally off - libc_hidden_proto(memcpy) */ +extern void restore_rt(void) __asm__ ("__restore_rt") attribute_hidden; +extern void restore(void) __asm__ ("__restore") attribute_hidden; /* If ACT is not NULL, change the action for SIG to *ACT. If OACT is not NULL, put the old action for SIG in *OACT. */ int -__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact) +__libc_sigaction(int sig, const struct sigaction *act, struct sigaction *oact) { - int result; - struct kernel_sigaction kact, koact; + struct sigaction kact; if (act) { - kact.k_sa_handler = act->sa_handler; - memcpy (&kact.sa_mask, &act->sa_mask, sizeof (sigset_t)); - kact.sa_flags = act->sa_flags | SA_RESTORER; - + memcpy(&kact, act, sizeof(kact)); + kact.sa_flags |= SA_RESTORER; kact.sa_restorer = &restore_rt; + act = &kact; } - - /* XXX The size argument hopefully will have to be changed to the - real size of the user-level sigset_t. */ - result = INLINE_SYSCALL (rt_sigaction, 4, - sig, act ? __ptrvalue (&kact) : NULL, - oact ? __ptrvalue (&koact) : NULL, _NSIG / 8); - if (oact && result >= 0) { - oact->sa_handler = koact.k_sa_handler; - memcpy (&oact->sa_mask, &koact.sa_mask, sizeof (sigset_t)); - oact->sa_flags = koact.sa_flags; - oact->sa_restorer = koact.sa_restorer; - } - return result; + /* NB: kernel (as of 2.6.25) will return EINVAL + * if sizeof(act->sa_mask) does not match kernel's sizeof(sigset_t) */ + return INLINE_SYSCALL(rt_sigaction, 4, sig, act, oact, sizeof(act->sa_mask)); } + #else -extern void restore (void) __asm__ ("__restore") attribute_hidden; +extern void restore(void) __asm__ ("__restore") attribute_hidden; /* If ACT is not NULL, change the action for SIG to *ACT. If OACT is not NULL, put the old action for SIG in *OACT. */ int -__libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact) +__libc_sigaction(int sig, const struct sigaction *act, struct sigaction *oact) { int result; struct old_kernel_sigaction kact, koact; -#ifdef SIGCANCEL - if (sig == SIGCANCEL) { - __set_errno (EINVAL); - return -1; - } -#endif - if (act) { kact.k_sa_handler = act->sa_handler; kact.sa_mask = act->sa_mask.__val[0]; kact.sa_flags = act->sa_flags | SA_RESTORER; kact.sa_restorer = &restore; } - - __asm__ __volatile__ ("syscall\n" - : "=a" (result) - : "0" (__NR_sigaction), "mr" (sig), - "c" (act ? __ptrvalue (&kact) : 0), - "d" (oact ? __ptrvalue (&koact) : 0)); - + __asm__ __volatile__ ( + "syscall\n" + : "=a" (result) + : "0" (__NR_sigaction), "mr" (sig), + "c" (act ? &kact : NULL), + "d" (oact ? &koact : NULL)); if (result < 0) { __set_errno(-result); return -1; } - if (oact) { oact->sa_handler = koact.k_sa_handler; oact->sa_mask.__val[0] = koact.sa_mask; @@ -117,34 +90,50 @@ __libc_sigaction (int sig, const struct sigaction *act, struct sigaction *oact) } return result; } + #endif + #ifndef LIBC_SIGACTION -libc_hidden_proto(sigaction) +# ifndef __UCLIBC_HAS_THREADS__ +strong_alias(__libc_sigaction,sigaction) +libc_hidden_def(sigaction) +# else weak_alias(__libc_sigaction,sigaction) libc_hidden_weak(sigaction) +# endif #endif + /* NOTE: Please think twice before making any changes to the bits of code below. GDB needs some intimate knowledge about it to recognize them as signal trampolines, and make backtraces through signal handlers work right. Important are both the names (__restore_rt) and the exact instruction sequence. If you ever feel the need to make any changes, please notify the - appropriate GDB maintainer. */ - -#define RESTORE(name, syscall) RESTORE2 (name, syscall) -# define RESTORE2(name, syscall) \ -__asm__ ( \ - ".text\n" \ - "__" #name ":\n" \ - " movq $" #syscall ", %rax\n" \ - " syscall\n" \ - ); + appropriate GDB maintainer. + + The unwind information starts a byte before __restore_rt, so that + it is found when unwinding, to get an address the unwinder assumes + will be in the middle of a call instruction. See the Linux kernel + (the i386 vsyscall, in particular) for an explanation of the complex + unwind information used here in order to get the traditional CFA. + */ + +#define RESTORE(name, syscall) RESTORE2(name, syscall) +#define RESTORE2(name, syscall) \ +__asm__ ( \ + "nop\n" \ + ".text\n" \ + "__" #name ":\n" \ + " movq $" #syscall ", %rax\n" \ + " syscall\n" \ +); + #ifdef __NR_rt_sigaction /* The return code for realtime-signals. */ -RESTORE (restore_rt, __NR_rt_sigreturn) +RESTORE(restore_rt, __NR_rt_sigreturn) #endif #ifdef __NR_sigreturn -RESTORE (restore, __NR_sigreturn) +RESTORE(restore, __NR_sigreturn) #endif |