diff options
Diffstat (limited to 'libshouldbeinlibc/wire.c')
| -rw-r--r-- | libshouldbeinlibc/wire.c | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/libshouldbeinlibc/wire.c b/libshouldbeinlibc/wire.c new file mode 100644 index 00000000..ca5d32b1 --- /dev/null +++ b/libshouldbeinlibc/wire.c @@ -0,0 +1,186 @@ +/* Function to wire down text and data (including from shared libraries) + Copyright (C) 1996,99,2000,01,02 Free Software Foundation, Inc. + Written by Michael I. Bushnell, p/BSG. + + This file is part of the GNU Hurd. + + The GNU Hurd 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 2, or (at + your option) any later version. + + The GNU Hurd 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, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ + + +#include <link.h> +#include <dlfcn.h> +#include <hurd.h> +#include <error.h> +#include <elf.h> + +#pragma weak _DYNAMIC +#pragma weak dlopen +#pragma weak dlclose +#pragma weak dlerror +#pragma weak dlsym +#ifndef RTLD_NOLOAD +#define RTLD_NOLOAD 0 +#endif + +/* Find the list of shared objects */ +static struct link_map * +loaded (void) +{ + ElfW(Dyn) *d; + + if (&_DYNAMIC == 0) /* statically linked */ + return 0; + + for (d = _DYNAMIC; d->d_tag != DT_NULL; ++d) + if (d->d_tag == DT_DEBUG) + { + struct r_debug *r = (void *) d->d_un.d_ptr; + return r->r_map; + } + + return 0; /* ld broken */ +} + +/* Compute the extent of a particular shared object. */ +static ElfW(Addr) +map_extent (struct link_map *map) +{ + /* In fact, LIB == MAP, but doing it this way makes it entirely kosher. */ + void *lib = dlopen (map->l_name, RTLD_NOLOAD); + if (lib == 0) + { + error (2, 0, "cannot dlopen %s: %s", map->l_name, dlerror ()); + /* NOTREACHED */ + return 0; + } + else + { + /* Find the _end symbol's runtime address and subtract the load base. */ + void *end = dlsym (lib, "_end"); + if (end == 0) + error (2, 0, "cannot wire library %s with no _end symbol: %s", + map->l_name, dlerror ()); + dlclose (lib); + return (ElfW(Addr)) end - map->l_addr; + } +} + +/* Wire down all memory currently allocated at START for LEN bytes; + host_priv is the privileged host port. */ +static void +wire_segment_internal (vm_address_t start, + vm_size_t len, + host_priv_t host_priv) +{ + vm_address_t addr; + vm_size_t size; + vm_prot_t protection; + vm_prot_t max_protection; + vm_inherit_t inheritance; + boolean_t shared; + mach_port_t object_name; + vm_offset_t offset; + error_t err; + volatile char *poke; + + do + { + addr = start; + err = vm_region (mach_task_self (), &addr, &size, &protection, + &max_protection, &inheritance, &shared, &object_name, + &offset); + if (err) + return; + + /* The current region begins at ADDR and is SIZE long. If it + extends beyond the LEN, prune it. */ + if (addr + size > start + len) + size = len - (addr - start); + + /* Set protection to allow all access possible */ + vm_protect (mach_task_self (), addr, size, 0, max_protection); + + /* Generate write faults */ + for (poke = (char *) addr; + (vm_address_t) poke < addr + size; + poke += vm_page_size) + *poke = *poke; + + /* Wire pages */ + vm_wire (host_priv, mach_task_self (), addr, size, max_protection); + + /* Set protection back to what it was */ + vm_protect (mach_task_self (), addr, size, 0, protection); + + + mach_port_deallocate (mach_task_self (), object_name); + + len -= (addr - start) + size; + start = addr + size; + } + while (len); +} + +/* Wire down all memory currently allocated at START for LEN bytes. */ +void +wire_segment (vm_address_t start, + vm_size_t len) +{ + mach_port_t host, device; + error_t err; + + err = get_privileged_ports (&host, &device); + if (!err) + { + wire_segment_internal (start, len, host); + mach_port_deallocate (mach_task_self (), host); + mach_port_deallocate (mach_task_self (), device); + } +} + + +/* Wire down all the text and data (including from shared libraries) + for the current program. */ +void +wire_task_self () +{ + struct link_map *map; + mach_port_t host, device; + error_t err; + extern char _edata, _etext, __data_start; + + err = get_privileged_ports (&host, &device); + if (err) + return; + + map = loaded (); + if (!map) + { + extern void _start (); + vm_address_t text_start = (vm_address_t) &_start; + wire_segment_internal (text_start, + (vm_size_t) (&_etext - text_start), + host); + wire_segment_internal ((vm_address_t) &__data_start, + (vm_size_t) (&_edata - &__data_start), + host); + } + else + while (map) + wire_segment ((vm_address_t) map->l_addr, map_extent (map)); + + mach_port_deallocate (mach_task_self (), host); + mach_port_deallocate (mach_task_self (), device); +} |