diff options
Diffstat (limited to 'lib/libc/amd64/gen/signalcontext.c')
| -rw-r--r-- | lib/libc/amd64/gen/signalcontext.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/lib/libc/amd64/gen/signalcontext.c b/lib/libc/amd64/gen/signalcontext.c new file mode 100644 index 0000000..1a2621a --- /dev/null +++ b/lib/libc/amd64/gen/signalcontext.c @@ -0,0 +1,106 @@ +/* + * Copyright (c) 2003 Marcel Moolenaar + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include <sys/ucontext.h> +#include <signal.h> +#include <stdlib.h> +#include <strings.h> + +typedef void (*handler_t)(uint64_t, uint64_t, uint64_t); + +/* Prototypes */ +static void sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args); + +__weak_reference(__signalcontext, signalcontext); + +int +__signalcontext(ucontext_t *ucp, int sig, __sighandler_t *func) +{ + uint64_t *args; + siginfo_t *sig_si; + ucontext_t *sig_uc; + uint64_t sp; + + /* Bail out if we don't have a valid ucontext pointer. */ + if (ucp == NULL) + abort(); + + /* + * Build a signal frame and copy the arguments of signal handler + * 'func' onto the stack and do the funky stack alignment. + * This means that we need an 8-byte-odd alignment since the ABI expects + * the return address to be pushed, thus breaking the 16 byte alignment. + */ + sp = (ucp->uc_mcontext.mc_rsp - 128 - sizeof(ucontext_t)) & ~15UL; + sig_uc = (ucontext_t *)sp; + bcopy(ucp, sig_uc, sizeof(*sig_uc)); + sp = (sp - sizeof(siginfo_t)) & ~15UL; + sig_si = (siginfo_t *)sp; + bzero(sig_si, sizeof(*sig_si)); + sig_si->si_signo = sig; + sp -= 3 * sizeof(uint64_t); + args = (uint64_t *)sp; + args[0] = sig; + args[1] = (intptr_t)sig_si; + args[2] = (intptr_t)sig_uc; + sp -= 16; + + /* + * Setup the ucontext of the signal handler. + */ + bzero(&ucp->uc_mcontext, sizeof(ucp->uc_mcontext)); + ucp->uc_mcontext.mc_fpformat = _MC_FPFMT_NODEV; + ucp->uc_mcontext.mc_ownedfp = _MC_FPOWNED_NONE; + ucp->uc_link = sig_uc; + sigdelset(&ucp->uc_sigmask, sig); + + ucp->uc_mcontext.mc_len = sizeof(mcontext_t); + ucp->uc_mcontext.mc_rdi = (register_t)ucp; + ucp->uc_mcontext.mc_rsi = (register_t)func; + ucp->uc_mcontext.mc_rdx = (register_t)args; + ucp->uc_mcontext.mc_rbp = (register_t)sp; + ucp->uc_mcontext.mc_rbx = (register_t)sp; + ucp->uc_mcontext.mc_rsp = (register_t)sp; + ucp->uc_mcontext.mc_rip = (register_t)sigctx_wrapper; + return (0); +} + +static void +sigctx_wrapper(ucontext_t *ucp, handler_t func, uint64_t *args) +{ + + (*func)(args[0], args[1], args[2]); + if (ucp->uc_link == NULL) + exit(0); + setcontext((const ucontext_t *)ucp->uc_link); + /* should never get here */ + abort(); + /* NOTREACHED */ +} |
