/* Page fault handling library. Copyright (C) 1998-2021 Bruno Haible This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ #ifndef _SIGSEGV_H #define _SIGSEGV_H /* Get size_t. */ #include /* Define the fault context structure. */ #if defined __linux__ || defined __ANDROID__ \ || (defined __FreeBSD__ && (defined __arm__ || defined __armhf__ || defined __arm64__)) \ || defined __NetBSD__ \ || defined _AIX || defined __sun \ || defined __CYGWIN__ /* Linux, FreeBSD, NetBSD, AIX, Solaris, Cygwin */ # include #elif (defined __APPLE__ && defined __MACH__) /* macOS */ # include #elif defined __HAIKU__ /* Haiku */ # include #endif /* Correct the value of SIGSTKSZ on some systems. glibc >= 2.34: When _GNU_SOURCE is defined, SIGSTKSZ is no longer a compile-time constant. But most programs need a simple constant. AIX 64-bit: original value 4096 is too small. HP-UX: original value 8192 is too small. Solaris 11/x86_64: original value 8192 is too small. */ #include #if __GLIBC__ >= 2 # undef SIGSTKSZ # if defined __ia64__ # define SIGSTKSZ 262144 # else # define SIGSTKSZ 65536 # endif #endif #if defined _AIX && defined _ARCH_PPC64 # undef SIGSTKSZ # define SIGSTKSZ 8192 #endif #if defined __hpux || (defined __sun && (defined __x86_64__ || defined __amd64__)) # undef SIGSTKSZ # define SIGSTKSZ 16384 #endif /* HAVE_SIGSEGV_RECOVERY is defined if the system supports catching SIGSEGV. */ #if defined __linux__ || defined __ANDROID__ || defined __GNU__ \ || defined __FreeBSD_kernel__ || (defined __FreeBSD__ && !(defined __sparc__ || defined __sparc64__)) || defined __DragonFly__ \ || defined __NetBSD__ \ || defined __OpenBSD__ \ || (defined __APPLE__ && defined __MACH__) \ || defined _AIX || defined __sgi || defined __sun \ || defined __CYGWIN__ || defined __HAIKU__ /* Linux, Hurd, GNU/kFreeBSD, FreeBSD, NetBSD, OpenBSD, macOS, AIX, IRIX, Solaris, Cygwin, Haiku */ # define HAVE_SIGSEGV_RECOVERY 1 #endif /* HAVE_STACK_OVERFLOW_RECOVERY is defined if stack overflow can be caught. */ #if defined __linux__ || defined __ANDROID__ || defined __GNU__ \ || defined __FreeBSD_kernel__ || (defined __FreeBSD__ && !(defined __sparc__ || defined __sparc64__)) || defined __DragonFly__ \ || (defined __NetBSD__ && !(defined __sparc__ || defined __sparc64__)) \ || defined __OpenBSD__ \ || (defined __APPLE__ && defined __MACH__) \ || defined _AIX || defined __sgi || defined __sun \ || defined __CYGWIN__ || defined __HAIKU__ /* Linux, Hurd, GNU/kFreeBSD, FreeBSD, NetBSD, OpenBSD, macOS, AIX, IRIX, Solaris, Cygwin, Haiku */ # define HAVE_STACK_OVERFLOW_RECOVERY 1 #endif #ifdef __cplusplus extern "C" { #endif #define LIBSIGSEGV_VERSION 0x020D /* version number: (major<<8) + minor */ extern int libsigsegv_version; /* Likewise */ /* -------------------------------------------------------------------------- */ #if 1 /* really only HAVE_SIGSEGV_RECOVERY */ /* * The mask of bits that are set to zero in a fault address that gets passed * to a global SIGSEGV handler. * On some platforms, the precise fault address is not known, only the memory * page into which the fault address falls. This is apparently allowed by POSIX: * * says: "For some implementations, the value of si_addr may be inaccurate." * In this case, the returned fault address is rounded down to a multiple of * getpagesize() = sysconf(_SC_PAGESIZE). * On such platforms, we define SIGSEGV_FAULT_ADDRESS_ALIGNMENT to be an upper * bound for getpagesize() (and, like getpagesize(), also a power of 2). * On the platforms where the returned fault address is the precise one, we * define SIGSEGV_FAULT_ADDRESS_ALIGNMENT to 1. */ # if defined __NetBSD__ && (defined __sparc__ || defined __sparc64__) /* getpagesize () is 0x1000 or 0x2000, depending on hardware. */ # define SIGSEGV_FAULT_ADDRESS_ALIGNMENT 0x2000UL # elif defined __linux__ && (defined __s390__ || defined __s390x__) /* getpagesize () is 0x1000. */ # define SIGSEGV_FAULT_ADDRESS_ALIGNMENT 0x1000UL # else # define SIGSEGV_FAULT_ADDRESS_ALIGNMENT 1UL # endif /* * The type of a global SIGSEGV handler. * The fault address, with the bits (SIGSEGV_FAULT_ADDRESS_ALIGNMENT - 1) * cleared, is passed as argument. * The access type (read access or write access) is not passed; your handler * has to know itself how to distinguish these two cases. * The second argument is 0, meaning it could also be a stack overflow, or 1, * meaning the handler should seriously try to fix the fault. * The return value should be nonzero if the handler has done its job * and no other handler should be called, or 0 if the handler declines * responsibility for the given address. * * The handler is run at a moment when nothing about the global state of the * program is known. Therefore it cannot use facilities that manipulate global * variables or locks. In particular, it cannot use malloc(); use mmap() * instead. It cannot use fopen(); use open() instead. Etc. All global * variables that are accessed by the handler should be marked 'volatile'. */ typedef int (*sigsegv_handler_t) (void* fault_address, int serious); /* * Installs a global SIGSEGV handler. * This should be called once only, and it ignores any previously installed * SIGSEGV handler. * Returns 0 on success, or -1 if the system doesn't support catching SIGSEGV. */ extern int sigsegv_install_handler (sigsegv_handler_t handler); /* * Deinstalls the global SIGSEGV handler. * This goes back to the state where no SIGSEGV handler is installed. */ extern void sigsegv_deinstall_handler (void); /* * Prepares leaving a SIGSEGV handler (through longjmp or similar means). * Control is transferred by calling CONTINUATION with CONT_ARG1, CONT_ARG2, * CONT_ARG3 as arguments. * CONTINUATION must not return. * The sigsegv_leave_handler function may return if called from a SIGSEGV * handler; its return value should be used as the handler's return value. * The sigsegv_leave_handler function does not return if called from a * stack overflow handler. */ extern int sigsegv_leave_handler (void (*continuation) (void*, void*, void*), void* cont_arg1, void* cont_arg2, void* cont_arg3); #endif /* HAVE_SIGSEGV_RECOVERY */ #if 1 /* really only HAVE_STACK_OVERFLOW_RECOVERY */ /* * The type of a context passed to a stack overflow handler. * This type is system dependent; on some platforms it is an 'ucontext_t *', * on some platforms it is a 'struct sigcontext *', on others merely an * opaque 'void *'. */ # if defined __linux__ || defined __ANDROID__ \ || (defined __FreeBSD__ && (defined __arm__ || defined __armhf__ || defined __arm64__)) \ || defined __NetBSD__ \ || (defined __APPLE__ && defined __MACH__) \ || defined _AIX || defined __sun \ || defined __CYGWIN__ || defined __HAIKU__ typedef ucontext_t *stackoverflow_context_t; # elif defined __GNU__ \ || defined __FreeBSD_kernel__ || (defined __FreeBSD__ && !(defined __sparc__ || defined __sparc64__)) \ || defined __OpenBSD__ || defined __sgi typedef struct sigcontext *stackoverflow_context_t; # else typedef void *stackoverflow_context_t; # endif /* * The type of a stack overflow handler. * Such a handler should perform a longjmp call in order to reduce the amount * of stack needed. It must not return. * The emergency argument is 0 when the stack could be repared, or 1 if the * application should better save its state and exit now. * * The handler is run at a moment when nothing about the global state of the * program is known. Therefore it cannot use facilities that manipulate global * variables or locks. In particular, it cannot use malloc(); use mmap() * instead. It cannot use fopen(); use open() instead. Etc. All global * variables that are accessed by the handler should be marked 'volatile'. */ typedef void (*stackoverflow_handler_t) (int emergency, stackoverflow_context_t scp); /* * Installs a stack overflow handler. * The extra_stack argument is a pointer to a pre-allocated area used as a * stack for executing the handler. It typically comes from a static variable * or from heap-allocated memoty; placing it on the main stack may fail on * some operating systems. * Its size, passed in extra_stack_size, should be sufficiently large. The * following code determines an appropriate size: * #include * #ifndef SIGSTKSZ / * glibc defines SIGSTKSZ for this purpose * / * # define SIGSTKSZ 16384 / * on most platforms, 16 KB are sufficient * / * #endif * Returns 0 on success, or -1 if the system doesn't support catching stack * overflow. */ extern int stackoverflow_install_handler (stackoverflow_handler_t handler, void* extra_stack, size_t extra_stack_size); /* * Deinstalls the stack overflow handler. */ extern void stackoverflow_deinstall_handler (void); #endif /* HAVE_STACK_OVERFLOW_RECOVERY */ /* -------------------------------------------------------------------------- */ #ifdef __cplusplus } #endif #endif /* _SIGSEGV_H */