diff options
Diffstat (limited to 'linker/linker.c')
| -rw-r--r-- | linker/linker.c | 1760 |
1 files changed, 0 insertions, 1760 deletions
diff --git a/linker/linker.c b/linker/linker.c deleted file mode 100644 index 7b19835..0000000 --- a/linker/linker.c +++ /dev/null @@ -1,1760 +0,0 @@ -/* - * Copyright (C) 2008 The Android Open Source Project - * All rights reserved. - * - * Redistribution and use in source and binary forms, with or without - * modification, are permitted provided that the following conditions - * are met: - * * Redistributions of source code must retain the above copyright - * notice, this list of conditions and the following disclaimer. - * * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS - * "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 - * COPYRIGHT OWNER OR CONTRIBUTORS 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 <linux/auxvec.h> - -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <fcntl.h> -#include <errno.h> -#include <dlfcn.h> -#include <sys/stat.h> - -//#include <pthread.h> - -#include <sys/mman.h> - -#include <sys/atomics.h> - -/* special private C library header - see Android.mk */ -#include <bionic_tls.h> - -#include "linker.h" -#include "linker_debug.h" - -#define SO_MAX 64 - -/* >>> IMPORTANT NOTE - READ ME BEFORE MODIFYING <<< - * - * Do NOT use malloc() and friends or pthread_*() code here. - * Don't use printf() either; it's caused mysterious memory - * corruption in the past. - * The linker runs before we bring up libc and it's easiest - * to make sure it does not depend on any complex libc features - * - * open issues / todo: - * - * - should we do anything special for STB_WEAK symbols? - * - are we doing everything we should for ARM_COPY relocations? - * - cleaner error reporting - * - configuration for paths (LD_LIBRARY_PATH?) - * - after linking, set as much stuff as possible to READONLY - * and NOEXEC - * - linker hardcodes PAGE_SIZE and PAGE_MASK because the kernel - * headers provide versions that are negative... - * - allocate space for soinfo structs dynamically instead of - * having a hard limit (64) - * - * features to add someday: - * - * - dlopen() and friends - * -*/ - - -static int link_image(soinfo *si, unsigned wr_offset); - -static int socount = 0; -static soinfo sopool[SO_MAX]; -static soinfo *freelist = NULL; -static soinfo *solist = &libdl_info; -static soinfo *sonext = &libdl_info; - -int debug_verbosity; -static int pid; - -#if STATS -struct _link_stats linker_stats; -#endif - -#if COUNT_PAGES -unsigned bitmask[4096]; -#endif - -#ifndef PT_ARM_EXIDX -#define PT_ARM_EXIDX 0x70000001 /* .ARM.exidx segment */ -#endif - -/* - * This function is an empty stub where GDB locates a breakpoint to get notified - * about linker activity. - */ -extern void __attribute__((noinline)) rtld_db_dlactivity(void); - -extern void sched_yield(void); - -static struct r_debug _r_debug = {1, NULL, &rtld_db_dlactivity, RT_CONSISTENT, 0}; -static struct link_map *r_debug_tail = 0; - -//static pthread_mutex_t _r_debug_lock = PTHREAD_MUTEX_INITIALIZER; - -static volatile int loader_lock = 0; - -static void insert_soinfo_into_debug_map(soinfo * info) -{ - struct link_map * map; - - /* Copy the necessary fields into the debug structure. - */ - map = &(info->linkmap); - map->l_addr = info->base; - map->l_name = (char*) info->name; - - /* Stick the new library at the end of the list. - * gdb tends to care more about libc than it does - * about leaf libraries, and ordering it this way - * reduces the back-and-forth over the wire. - */ - if (r_debug_tail) { - r_debug_tail->l_next = map; - map->l_prev = r_debug_tail; - map->l_next = 0; - } else { - _r_debug.r_map = map; - map->l_prev = 0; - map->l_next = 0; - } - r_debug_tail = map; -} - -void notify_gdb_of_load(soinfo * info) -{ - if (info->flags & FLAG_EXE) { - // GDB already knows about the main executable - return; - } - - /* yes, this is a little gross, but it does avoid - ** pulling in pthread_*() and at the moment we don't - ** dlopen() anything anyway - */ - while(__atomic_swap(1, &loader_lock) != 0) { - sched_yield(); - usleep(5000); - } - - _r_debug.r_state = RT_ADD; - rtld_db_dlactivity(); - - insert_soinfo_into_debug_map(info); - - _r_debug.r_state = RT_CONSISTENT; - rtld_db_dlactivity(); - - __atomic_swap(0, &loader_lock); -} - -void notify_gdb_of_libraries() -{ - _r_debug.r_state = RT_ADD; - rtld_db_dlactivity(); - _r_debug.r_state = RT_CONSISTENT; - rtld_db_dlactivity(); -} - -static soinfo *alloc_info(const char *name) -{ - soinfo *si; - - if(strlen(name) >= SOINFO_NAME_LEN) { - ERROR("%5d library name %s too long\n", pid, name); - return 0; - } - - /* The freelist is populated when we call free_info(), which in turn is - done only by dlclose(), which is not likely to be used. - */ - if (!freelist) { - if(socount == SO_MAX) { - ERROR("%5d too many libraries when loading %s\n", pid, name); - return NULL; - } - freelist = sopool + socount++; - freelist->next = NULL; - } - - si = freelist; - freelist = freelist->next; - - /* Make sure we get a clean block of soinfo */ - memset(si, 0, sizeof(soinfo)); - strcpy((char*) si->name, name); - sonext->next = si; - si->next = NULL; - si->refcount = 0; - sonext = si; - - TRACE("%5d name %s: allocated soinfo @ %p\n", pid, name, si); - return si; -} - -static void free_info(soinfo *si) -{ - soinfo *prev = NULL, *trav; - - TRACE("%5d name %s: freeing soinfo @ %p\n", pid, si->name, si); - - for(trav = solist; trav != NULL; trav = trav->next){ - if (trav == si) - break; - prev = trav; - } - if (trav == NULL) { - /* si was not ni solist */ - ERROR("%5d name %s is not in solist!\n", pid, si->name); - return; - } - - /* prev will never be NULL, because the first entry in solist is - always the static libdl_info. - */ - prev->next = si->next; - if (si == sonext) sonext = prev; - si->next = freelist; - freelist = si; -} - -#ifndef LINKER_TEXT_BASE -#error "linker's makefile must define LINKER_TEXT_BASE" -#endif -#ifndef LINKER_AREA_SIZE -#error "linker's makefile must define LINKER_AREA_SIZE" -#endif -#define LINKER_BASE ((LINKER_TEXT_BASE) & 0xfff00000) -#define LINKER_TOP (LINKER_BASE + (LINKER_AREA_SIZE)) - -const char *addr_to_name(unsigned addr) -{ - soinfo *si; - - for(si = solist; si != 0; si = si->next){ - if((addr >= si->base) && (addr < (si->base + si->size))) { - return si->name; - } - } - - if((addr >= LINKER_BASE) && (addr < LINKER_TOP)){ - return "linker"; - } - - return ""; -} - -/* For a given PC, find the .so that it belongs to. - * Returns the base address of the .ARM.exidx section - * for that .so, and the number of 8-byte entries - * in that section (via *pcount). - * - * Intended to be called by libc's __gnu_Unwind_Find_exidx(). - * - * This function is exposed via dlfcn.c and libdl.so. - */ -#ifdef ANDROID_ARM_LINKER -_Unwind_Ptr dl_unwind_find_exidx(_Unwind_Ptr pc, int *pcount) -{ - soinfo *si; - unsigned addr = (unsigned)pc; - - if ((addr < LINKER_BASE) || (addr >= LINKER_TOP)) { - for (si = solist; si != 0; si = si->next){ - if ((addr >= si->base) && (addr < (si->base + si->size))) { - *pcount = si->ARM_exidx_count; - return (_Unwind_Ptr)(si->base + (unsigned long)si->ARM_exidx); - } - } - } - *pcount = 0; - return NULL; -} -#elif defined(ANDROID_X86_LINKER) -/* Here, we only have to provide a callback to iterate across all the - * loaded libraries. gcc_eh does the rest. */ -int -dl_iterate_phdr(int (*cb)(struct dl_phdr_info *info, size_t size, void *data), - void *data) -{ - soinfo *si; - struct dl_phdr_info dl_info; - int rv = 0; - - for (si = solist; si != NULL; si = si->next) { - dl_info.dlpi_addr = si->linkmap.l_addr; - dl_info.dlpi_name = si->linkmap.l_name; - dl_info.dlpi_phdr = si->phdr; - dl_info.dlpi_phnum = si->phnum; - rv = cb(&dl_info, sizeof (struct dl_phdr_info), data); - if (rv != 0) - break; - } - return rv; -} -#endif - -static Elf32_Sym *_elf_lookup(soinfo *si, unsigned hash, const char *name) -{ - Elf32_Sym *s; - Elf32_Sym *symtab = si->symtab; - const char *strtab = si->strtab; - unsigned n; - - TRACE_TYPE(LOOKUP, "%5d SEARCH %s in %s@0x%08x %08x %d\n", pid, - name, si->name, si->base, hash, hash % si->nbucket); - n = hash % si->nbucket; - - for(n = si->bucket[hash % si->nbucket]; n != 0; n = si->chain[n]){ - s = symtab + n; - if(strcmp(strtab + s->st_name, name)) continue; - - /* only concern ourselves with global symbols */ - switch(ELF32_ST_BIND(s->st_info)){ - case STB_GLOBAL: - /* no section == undefined */ - if(s->st_shndx == 0) continue; - - case STB_WEAK: - TRACE_TYPE(LOOKUP, "%5d FOUND %s in %s (%08x) %d\n", pid, - name, si->name, s->st_value, s->st_size); - return s; - } - } - - return 0; -} - -static unsigned elfhash(const char *_name) -{ - const unsigned char *name = (const unsigned char *) _name; - unsigned h = 0, g; - - while(*name) { - h = (h << 4) + *name++; - g = h & 0xf0000000; - h ^= g; - h ^= g >> 24; - } - return h; -} - -static Elf32_Sym * -_do_lookup_in_so(soinfo *si, const char *name, unsigned *elf_hash) -{ - if (*elf_hash == 0) - *elf_hash = elfhash(name); - return _elf_lookup (si, *elf_hash, name); -} - -/* This is used by dl_sym() */ -Elf32_Sym *lookup_in_library(soinfo *si, const char *name) -{ - unsigned unused = 0; - return _do_lookup_in_so(si, name, &unused); -} - -static Elf32_Sym * -_do_lookup(soinfo *user_si, const char *name, unsigned *base) -{ - unsigned elf_hash = 0; - Elf32_Sym *s = NULL; - soinfo *si; - - /* Look for symbols in the local scope first (the object who is - * searching). This happens with C++ templates on i386 for some - * reason. */ - if (user_si) { - s = _do_lookup_in_so(user_si, name, &elf_hash); - if (s != NULL) - *base = user_si->base; - } - - for(si = solist; (s == NULL) && (si != NULL); si = si->next) - { - if((si->flags & FLAG_ERROR) || (si == user_si)) - continue; - s = _do_lookup_in_so(si, name, &elf_hash); - if (s != NULL) { - *base = si->base; - break; - } - } - - if (s != NULL) { - TRACE_TYPE(LOOKUP, "%5d %s s->st_value = 0x%08x, " - "si->base = 0x%08x\n", pid, name, s->st_value, si->base); - return s; - } - - return 0; -} - -/* This is used by dl_sym() */ -Elf32_Sym *lookup(const char *name, unsigned *base) -{ - return _do_lookup(NULL, name, base); -} - -#if 0 -static void dump(soinfo *si) -{ - Elf32_Sym *s = si->symtab; - unsigned n; - - for(n = 0; n < si->nchain; n++) { - TRACE("%5d %04d> %08x: %02x %04x %08x %08x %s\n", pid, n, s, - s->st_info, s->st_shndx, s->st_value, s->st_size, - si->strtab + s->st_name); - s++; - } -} -#endif - -static const char *sopaths[] = { - "/system/lib", - "/lib", - 0 -}; - -static int _open_lib(const char *name) -{ - int fd; - struct stat filestat; - - if ((stat(name, &filestat) >= 0) && S_ISREG(filestat.st_mode)) { - if ((fd = open(name, O_RDONLY)) >= 0) - return fd; - } - - return -1; -} - -/* TODO: Need to add support for initializing the so search path with - * LD_LIBRARY_PATH env variable for non-setuid programs. */ -static int open_library(const char *name) -{ - int fd; - char buf[512]; - const char **path; - - TRACE("[ %5d opening %s ]\n", pid, name); - - if(name == 0) return -1; - if(strlen(name) > 256) return -1; - - if ((name[0] == '/') && ((fd = _open_lib(name)) >= 0)) - return fd; - - for (path = sopaths; *path; path++) { - snprintf(buf, sizeof(buf), "%s/%s", *path, name); - if ((fd = _open_lib(buf)) >= 0) - return fd; - } - - return -1; -} - -static unsigned libbase = LIBBASE; - -/* temporary space for holding the first page of the shared lib - * which contains the elf header (with the pht). */ -static unsigned char __header[PAGE_SIZE]; - -typedef struct { - long mmap_addr; - char tag[4]; /* 'P', 'R', 'E', ' ' */ -} prelink_info_t; - -/* Returns the requested base address if the library is prelinked, - * and 0 otherwise. */ -static unsigned long -is_prelinked(int fd, const char *name) -{ - off_t sz; - prelink_info_t info; - - sz = lseek(fd, -sizeof(prelink_info_t), SEEK_END); - if (sz < 0) { - ERROR("lseek() failed!\n"); - return 0; - } - - if (read(fd, &info, sizeof(info)) != sizeof(info)) { - WARN("Could not read prelink_info_t structure for `%s`\n", name); - return 0; - } - - if (strncmp(info.tag, "PRE ", 4)) { - WARN("`%s` is not a prelinked library\n", name); - return 0; - } - - return (unsigned long)info.mmap_addr; -} - -/* verify_elf_object - * Verifies if the object @ base is a valid ELF object - * - * Args: - * - * Returns: - * 0 on success - * -1 if no valid ELF object is found @ base. - */ -static int -verify_elf_object(void *base, const char *name) -{ - Elf32_Ehdr *hdr = (Elf32_Ehdr *) base; - - if (hdr->e_ident[EI_MAG0] != ELFMAG0) return -1; - if (hdr->e_ident[EI_MAG1] != ELFMAG1) return -1; - if (hdr->e_ident[EI_MAG2] != ELFMAG2) return -1; - if (hdr->e_ident[EI_MAG3] != ELFMAG3) return -1; - - /* TODO: Should we verify anything else in the header? */ - - return 0; -} - - -/* get_lib_extents - * Retrieves the base (*base) address where the ELF object should be - * mapped and its overall memory size (*total_sz). - * - * Args: - * fd: Opened file descriptor for the library - * name: The name of the library - * _hdr: Pointer to the header page of the library - * total_sz: Total size of the memory that should be allocated for - * this library - * - * Returns: - * -1 if there was an error while trying to get the lib extents. - * The possible reasons are: - * - Could not determine if the library was prelinked. - * - The library provided is not a valid ELF object - * 0 if the library did not request a specific base offset (normal - * for non-prelinked libs) - * > 0 if the library requests a specific address to be mapped to. - * This indicates a pre-linked library. - */ -static unsigned -get_lib_extents(int fd, const char *name, void *__hdr, unsigned *total_sz) -{ - unsigned req_base; - unsigned min_vaddr = 0xffffffff; - unsigned max_vaddr = 0; - unsigned char *_hdr = (unsigned char *)__hdr; - Elf32_Ehdr *ehdr = (Elf32_Ehdr *)_hdr; - Elf32_Phdr *phdr; - int cnt; - - TRACE("[ %5d Computing extents for '%s'. ]\n", pid, name); - if (verify_elf_object(_hdr, name) < 0) { - ERROR("%5d - %s is not a valid ELF object\n", pid, name); - return (unsigned)-1; - } - - req_base = (unsigned) is_prelinked(fd, name); - if (req_base == (unsigned)-1) - return -1; - else if (req_base != 0) { - TRACE("[ %5d - Prelinked library '%s' requesting base @ 0x%08x ]\n", - pid, name, req_base); - } else { - TRACE("[ %5d - Non-prelinked library '%s' found. ]\n", pid, name); - } - - phdr = (Elf32_Phdr *)(_hdr + ehdr->e_phoff); - - /* find the min/max p_vaddrs from all the PT_LOAD segments so we can - * get the range. */ - for (cnt = 0; cnt < ehdr->e_phnum; ++cnt, ++phdr) { - if (phdr->p_type == PT_LOAD) { - if ((phdr->p_vaddr + phdr->p_memsz) > max_vaddr) - max_vaddr = phdr->p_vaddr + phdr->p_memsz; - if (phdr->p_vaddr < min_vaddr) - min_vaddr = phdr->p_vaddr; - } - } - - if ((min_vaddr == 0xffffffff) && (max_vaddr == 0)) { - ERROR("%5d - No loadable segments found in %s.\n", pid, name); - return (unsigned)-1; - } - - /* truncate min_vaddr down to page boundary */ - min_vaddr &= ~PAGE_MASK; - - /* round max_vaddr up to the next page */ - max_vaddr = (max_vaddr + PAGE_SIZE - 1) & ~PAGE_MASK; - - *total_sz = (max_vaddr - min_vaddr); - return (unsigned)req_base; -} - -/* alloc_mem_region - * - * This function reserves a chunk of memory to be used for mapping in - * the shared library. We reserve the entire memory region here, and - * then the rest of the linker will relocate the individual loadable - * segments into the correct locations within this memory range. - * - * Args: - * req_base: The requested base of the allocation. If 0, a sane one will be - * chosen in the range LIBBASE <= base < LIBLAST. - * sz: The size of the allocation. - * - * Returns: - * NULL on failure, and non-NULL pointer to memory region on success. - */ -static void * -alloc_mem_region(const char *name, unsigned req_base, unsigned sz) -{ - void *base; - - if (req_base) { - /* we should probably map it as PROT_NONE, but the init code needs - * to read the phdr, so mark everything as readable. */ - base = mmap((void *)req_base, sz, PROT_READ | PROT_EXEC, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if (base == MAP_FAILED) { - WARN("%5d can NOT map (prelinked) library '%s' at 0x%08x " - "as requested, will try general pool: %d (%s)\n", - pid, name, req_base, errno, strerror(errno)); - } else if (base != (void *)req_base) { - ERROR("OOPS: %5d prelinked library '%s' mapped at 0x%08x, " - "not at 0x%08x\n", pid, name, (unsigned)base, req_base); - munmap(base, sz); - return NULL; - } - - /* Here we know that we got a valid allocation. Hooray! */ - return base; - } - - /* We either did not request a specific base address to map at - * (i.e. not-prelinked) OR we could not map at the requested address. - * Try to find a memory range in our "reserved" area that can be mapped. - */ - while(libbase < LIBLAST) { - base = mmap((void*) libbase, sz, PROT_READ | PROT_EXEC, - MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - - if(((unsigned)base) == libbase) { - /* success -- got the address we wanted */ - return base; - } - - /* If we got a different address than requested (rather than - * just a failure), we need to unmap the mismapped library - * before trying again - */ - if(base != MAP_FAILED) - munmap(base, sz); - - libbase += LIBINC; - } - - ERROR("OOPS: %5d cannot map library '%s'. no vspace available.\n", - pid, name); - return NULL; -} - -#define MAYBE_MAP_FLAG(x,from,to) (((x) & (from)) ? (to) : 0) -#define PFLAGS_TO_PROT(x) (MAYBE_MAP_FLAG((x), PF_X, PROT_EXEC) | \ - MAYBE_MAP_FLAG((x), PF_R, PROT_READ) | \ - MAYBE_MAP_FLAG((x), PF_W, PROT_WRITE)) -/* load_segments - * - * This function loads all the loadable (PT_LOAD) segments into memory - * at their appropriate memory offsets off the base address. - * - * Args: - * fd: Open file descriptor to the library to load. - * header: Pointer to a header page that contains the ELF header. - * This is needed since we haven't mapped in the real file yet. - * si: ptr to soinfo struct describing the shared object. - * - * Returns: - * 0 on success, -1 on failure. - */ -static int -load_segments(int fd, void *header, soinfo *si) -{ - Elf32_Ehdr *ehdr = (Elf32_Ehdr *)header; - Elf32_Phdr *phdr = (Elf32_Phdr *)((unsigned char *)header + ehdr->e_phoff); - unsigned char *base = (unsigned char *)si->base; - int cnt; - unsigned len; - unsigned char *tmp; - unsigned char *pbase; - unsigned char *extra_base; - unsigned extra_len; - unsigned total_sz = 0; - - si->wrprotect_start = 0xffffffff; - si->wrprotect_end = 0; - - TRACE("[ %5d - Begin loading segments for '%s' @ 0x%08x ]\n", - pid, si->name, (unsigned)si->base); - /* Now go through all the PT_LOAD segments and map them into memory - * at the appropriate locations. */ - for (cnt = 0; cnt < ehdr->e_phnum; ++cnt, ++phdr) { - if (phdr->p_type == PT_LOAD) { - DEBUG_DUMP_PHDR(phdr, "PT_LOAD", pid); - /* we want to map in the segment on a page boundary */ - tmp = base + (phdr->p_vaddr & (~PAGE_MASK)); - /* add the # of bytes we masked off above to the total length. */ - len = phdr->p_filesz + (phdr->p_vaddr & PAGE_MASK); - - TRACE("[ %d - Trying to load segment from '%s' @ 0x%08x " - "(0x%08x). p_vaddr=0x%08x p_offset=0x%08x ]\n", pid, si->name, - (unsigned)tmp, len, phdr->p_vaddr, phdr->p_offset); - pbase = mmap(tmp, len, PFLAGS_TO_PROT(phdr->p_flags), - MAP_PRIVATE | MAP_FIXED, fd, - phdr->p_offset & (~PAGE_MASK)); - if (pbase == MAP_FAILED) { - ERROR("%d failed to map segment from '%s' @ 0x%08x (0x%08x). " - "p_vaddr=0x%08x p_offset=0x%08x\n", pid, si->name, - (unsigned)tmp, len, phdr->p_vaddr, phdr->p_offset); - goto fail; - } - - /* If 'len' didn't end on page boundary, and it's a writable - * segment, zero-fill the rest. */ - if ((len & PAGE_MASK) && (phdr->p_flags & PF_W)) - memset((void *)(pbase + len), 0, PAGE_SIZE - (len & PAGE_MASK)); - - /* Check to see if we need to extend the map for this segment to - * cover the diff between filesz and memsz (i.e. for bss). - * - * base _+---------------------+ page boundary - * . . - * | | - * . . - * pbase _+---------------------+ page boundary - * | | - * . . - * base + p_vaddr _| | - * . \ \ . - * . | filesz | . - * pbase + len _| / | | - * <0 pad> . . . - * extra_base _+------------|--------+ page boundary - * / . . . - * | . . . - * | +------------|--------+ page boundary - * extra_len-> | | | | - * | . | memsz . - * | . | . - * \ _| / | - * . . - * | | - * _+---------------------+ page boundary - */ - tmp = (unsigned char *)(((unsigned)pbase + len + PAGE_SIZE - 1) & - (~PAGE_MASK)); - if (tmp < (base + phdr->p_vaddr + phdr->p_memsz)) { - extra_len = base + phdr->p_vaddr + phdr->p_memsz - tmp; - TRACE("[ %5d - Need to extend segment from '%s' @ 0x%08x " - "(0x%08x) ]\n", pid, si->name, (unsigned)tmp, extra_len); - /* map in the extra page(s) as anonymous into the range. - * This is probably not necessary as we already mapped in - * the entire region previously, but we just want to be - * sure. This will also set the right flags on the region - * (though we can probably accomplish the same thing with - * mprotect). - */ - extra_base = mmap((void *)tmp, extra_len, - PFLAGS_TO_PROT(phdr->p_flags), - MAP_PRIVATE | MAP_FIXED | MAP_ANONYMOUS, - -1, 0); - if (extra_base == MAP_FAILED) { - ERROR("[ %5d - failed to extend segment from '%s' @ 0x%08x " - "(0x%08x) ]\n", pid, si->name, (unsigned)tmp, - extra_len); - goto fail; - } - /* TODO: Check if we need to memset-0 this region. - * Anonymous mappings are zero-filled copy-on-writes, so we - * shouldn't need to. */ - TRACE("[ %5d - Segment from '%s' extended @ 0x%08x " - "(0x%08x)\n", pid, si->name, (unsigned)extra_base, - extra_len); - } - /* set the len here to show the full extent of the segment we - * just loaded, mostly for debugging */ - len = (((unsigned)base + phdr->p_vaddr + phdr->p_memsz + - PAGE_SIZE - 1) & (~PAGE_MASK)) - (unsigned)pbase; - TRACE("[ %5d - Successfully loaded segment from '%s' @ 0x%08x " - "(0x%08x). p_vaddr=0x%08x p_offset=0x%08x\n", pid, si->name, - (unsigned)pbase, len, phdr->p_vaddr, phdr->p_offset); - total_sz += len; - /* Make the section writable just in case we'll have to write to - * it during relocation (i.e. text segment). However, we will - * remember what range of addresses should be write protected. - * - */ - if (!(phdr->p_flags & PF_W)) { - if ((unsigned)pbase < si->wrprotect_start) - si->wrprotect_start = (unsigned)pbase; - if (((unsigned)pbase + len) > si->wrprotect_end) - si->wrprotect_end = (unsigned)pbase + len; - mprotect(pbase, len, - PFLAGS_TO_PROT(phdr->p_flags) | PROT_WRITE); - } - } else if (phdr->p_type == PT_DYNAMIC) { - DEBUG_DUMP_PHDR(phdr, "PT_DYNAMIC", pid); - /* this segment contains the dynamic linking information */ - si->dynamic = (unsigned *)(base + phdr->p_vaddr); - } else { -#ifdef ANDROID_ARM_LINKER - if (phdr->p_type == PT_ARM_EXIDX) { - DEBUG_DUMP_PHDR(phdr, "PT_ARM_EXIDX", pid); - /* exidx entries (used for stack unwinding) are 8 bytes each. - */ - si->ARM_exidx = (unsigned *)phdr->p_vaddr; - si->ARM_exidx_count = phdr->p_memsz / 8; - } -#endif - } - - } - - /* Sanity check */ - if (total_sz > si->size) { - ERROR("%5d - Total length (0x%08x) of mapped segments from '%s' is " - "greater than what was allocated (0x%08x). THIS IS BAD!\n", - pid, total_sz, si->name, si->size); - goto fail; - } - - TRACE("[ %5d - Finish loading segments for '%s' @ 0x%08x. " - "Total memory footprint: 0x%08x bytes ]\n", pid, si->name, - (unsigned)si->base, si->size); - return 0; - -fail: - /* We can just blindly unmap the entire region even though some things - * were mapped in originally with anonymous and others could have been - * been mapped in from the file before we failed. The kernel will unmap - * all the pages in the range, irrespective of how they got there. - */ - munmap((void *)si->base, si->size); - si->flags |= FLAG_ERROR; - return -1; -} - -/* TODO: Implement this to take care of the fact that Android ARM - * ELF objects shove everything into a single loadable segment that has the - * write bit set. wr_offset is then used to set non-(data|bss) pages to be - * non-writable. - */ -#if 0 -static unsigned -get_wr_offset(int fd, const char *name, Elf32_Ehdr *ehdr) -{ - Elf32_Shdr *shdr_start; - Elf32_Shdr *shdr; - int shdr_sz = ehdr->e_shnum * sizeof(Elf32_Shdr); - int cnt; - unsigned wr_offset = 0xffffffff; - - shdr_start = mmap(0, shdr_sz, PROT_READ, MAP_PRIVATE, fd, - ehdr->e_shoff & (~PAGE_MASK)); - if (shdr_start == MAP_FAILED) { - WARN("%5d - Could not read section header info from '%s'. Will not " - "not be able to determine write-protect offset.\n", pid, name); - return (unsigned)-1; - } - - for(cnt = 0, shdr = shdr_start; cnt < ehdr->e_shnum; ++cnt, ++shdr) { - if ((shdr->sh_type != SHT_NULL) && (shdr->sh_flags & SHF_WRITE) && - (shdr->sh_addr < wr_offset)) { - wr_offset = shdr->sh_addr; - } - } - - munmap(shdr_start, shdr_sz); - return wr_offset; -} -#endif - -static soinfo * -load_library(const char *name) -{ - int fd = open_library(name); - int cnt; - unsigned ext_sz; - unsigned req_base; - void *base; - soinfo *si; - Elf32_Ehdr *hdr; - - if(fd == -1) - return NULL; - - /* We have to read the ELF header to figure out what to do with this image - */ - if (lseek(fd, 0, SEEK_SET) < 0) { - ERROR("lseek() failed!\n"); - goto fail; - } - - if ((cnt = read(fd, &__header[0], PAGE_SIZE)) < 0) { - ERROR("read() failed!\n"); - goto fail; - } - - /* Parse the ELF header and get the size of the memory footprint for - * the library */ - req_base = get_lib_extents(fd, name, &__header[0], &ext_sz); - if (req_base == (unsigned)-1) - goto fail; - TRACE("[ %5d - '%s' (%s) wants base=0x%08x sz=0x%08x ]\n", pid, name, - (req_base ? "prelinked" : "not pre-linked"), req_base, ext_sz); - - /* Carve out a chunk of memory where we will map in the individual - * segments */ - base = alloc_mem_region(name, req_base, ext_sz); - if (base == NULL) - goto fail; - TRACE("[ %5d allocated memory for %s @ %p (0x%08x) ]\n", - pid, name, base, (unsigned) ext_sz); - - /* Now configure the soinfo struct where we'll store all of our data - * for the ELF object. If the loading fails, we waste the entry, but - * same thing would happen if we failed during linking. Configuring the - * soinfo struct here is a lot more convenient. - */ - si = alloc_info(name); - if (si == NULL) - goto fail; - - si->base = (unsigned)base; - si->size = ext_sz; - si->flags = 0; - si->entry = 0; - si->dynamic = (unsigned *)-1; - - /* Now actually load the library's segments into right places in memory */ - if (load_segments(fd, &__header[0], si) < 0) - goto fail; - - /* this might not be right. Technically, we don't even need this info - * once we go through 'load_segments'. */ - hdr = (Elf32_Ehdr *)base; - si->phdr = (Elf32_Phdr *)((unsigned char *)si->base + hdr->e_phoff); - si->phnum = hdr->e_phnum; - /**/ - - close(fd); - return si; - -fail: - close(fd); - return NULL; -} - -static soinfo * -init_library(soinfo *si) -{ - unsigned wr_offset = 0xffffffff; - unsigned libbase_before = 0; - unsigned libbase_after = 0; - - /* At this point we know that whatever is loaded @ base is a valid ELF - * shared library whose segments are properly mapped in. */ - TRACE("[ %5d init_library base=0x%08x sz=0x%08x name='%s') ]\n", - pid, si->base, si->size, si->name); - - if (si->base < LIBBASE || si->base >= LIBLAST) - si->flags |= FLAG_PRELINKED; - - /* Adjust libbase for the size of this library, rounded up to - ** LIBINC alignment. Make note of the previous and current - ** value of libbase to allow us to roll back in the event of - ** a link failure. - */ - if (!(si->flags & FLAG_PRELINKED)) { - libbase_before = libbase; - libbase += (si->size + (LIBINC - 1)) & (~(LIBINC - 1)); - libbase_after = libbase; - } - - if(link_image(si, wr_offset)) { - /* We failed to link. However, we can only restore libbase - ** if no additional libraries have moved it since we updated it. - */ - if(!(si->flags & FLAG_PRELINKED) && (libbase == libbase_after)) { - libbase = libbase_before; - } - munmap((void *)si->base, si->size); - return NULL; - } - - return si; -} - -soinfo *find_library(const char *name) -{ - soinfo *si; - - for(si = solist; si != 0; si = si->next){ - if(!strcmp(name, si->name)) { - if(si->flags & FLAG_ERROR) return 0; - if(si->flags & FLAG_LINKED) return si; - ERROR("OOPS: %5d recursive link to '%s'\n", pid, si->name); - return 0; - } - } - - TRACE("[ %5d '%s' has not been loaded yet. Locating...]\n", pid, name); - si = load_library(name); - if(si == NULL) - return NULL; - return init_library(si); -} - -/* TODO: - * notify gdb of unload - * for non-prelinked libraries, find a way to decrement libbase - */ -static void call_destructors(soinfo *si); -unsigned unload_library(soinfo *si) -{ - unsigned *d; - if (si->refcount == 1) { - TRACE("%5d unloading '%s'\n", pid, si->name); - call_destructors(si); - - for(d = si->dynamic; *d; d += 2) { - if(d[0] == DT_NEEDED){ - TRACE("%5d %s needs to unload %s\n", pid, - si->name, si->strtab + d[1]); - soinfo *lsi = find_library(si->strtab + d[1]); - if(lsi) - unload_library(lsi); - else - ERROR("%5d could not unload '%s'\n", - pid, si->strtab + d[1]); - } - } - - munmap((char *)si->base, si->size); - free_info(si); - si->refcount = 0; - } - else { - si->refcount--; - PRINT("%5d not unloading '%s', decrementing refcount to %d\n", - pid, si->name, si->refcount); - } - return si->refcount; -} - -/* TODO: don't use unsigned for addrs below. It works, but is not - * ideal. They should probably be either uint32_t, Elf32_Addr, or unsigned - * long. - */ -static int reloc_library(soinfo *si, Elf32_Rel *rel, unsigned count) -{ - Elf32_Sym *symtab = si->symtab; - const char *strtab = si->strtab; - Elf32_Sym *s; - unsigned base; - Elf32_Rel *start = rel; - unsigned idx; - - for (idx = 0; idx < count; ++idx) { - unsigned type = ELF32_R_TYPE(rel->r_info); - unsigned sym = ELF32_R_SYM(rel->r_info); - unsigned reloc = (unsigned)(rel->r_offset + si->base); - unsigned sym_addr = 0; - char *sym_name = NULL; - - DEBUG("%5d Processing '%s' relocation at index %d\n", pid, - si->name, idx); - if(sym != 0) { - s = _do_lookup(si, strtab + symtab[sym].st_name, &base); - if(s == 0) { - ERROR("%5d cannot locate '%s'...\n", pid, sym_name); - return -1; - } -#if 0 - if((base == 0) && (si->base != 0)){ - /* linking from libraries to main image is bad */ - ERROR("%5d cannot locate '%s'...\n", - pid, strtab + symtab[sym].st_name); - return -1; - } -#endif - if ((s->st_shndx == SHN_UNDEF) && (s->st_value != 0)) { - ERROR("%5d In '%s', shndx=%d && value=0x%08x. We do not " - "handle this yet\n", pid, si->name, s->st_shndx, - s->st_value); - return -1; - } - sym_addr = (unsigned)(s->st_value + base); - sym_name = (char *)(strtab + symtab[sym].st_name); - COUNT_RELOC(RELOC_SYMBOL); - } else { - s = 0; - } - -/* TODO: This is ugly. Split up the relocations by arch into - * different files. - */ - switch(type){ -#if defined(ANDROID_ARM_LINKER) - case R_ARM_JUMP_SLOT: - COUNT_RELOC(RELOC_ABSOLUTE); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO JMP_SLOT %08x <- %08x %s\n", pid, - reloc, sym_addr, sym_name); - *((unsigned*)reloc) = sym_addr; - break; - case R_ARM_GLOB_DAT: - COUNT_RELOC(RELOC_ABSOLUTE); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO GLOB_DAT %08x <- %08x %s\n", pid, - reloc, sym_addr, sym_name); - *((unsigned*)reloc) = sym_addr; - break; - case R_ARM_ABS32: - COUNT_RELOC(RELOC_ABSOLUTE); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO ABS %08x <- %08x %s\n", pid, - reloc, sym_addr, sym_name); - *((unsigned*)reloc) += sym_addr; - break; -#elif defined(ANDROID_X86_LINKER) - case R_386_JUMP_SLOT: - COUNT_RELOC(RELOC_ABSOLUTE); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO JMP_SLOT %08x <- %08x %s\n", pid, - reloc, sym_addr, sym_name); - *((unsigned*)reloc) = sym_addr; - break; - case R_386_GLOB_DAT: - COUNT_RELOC(RELOC_ABSOLUTE); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO GLOB_DAT %08x <- %08x %s\n", pid, - reloc, sym_addr, sym_name); - *((unsigned*)reloc) = sym_addr; - break; -#endif /* ANDROID_*_LINKER */ - -#if defined(ANDROID_ARM_LINKER) - case R_ARM_RELATIVE: -#elif defined(ANDROID_X86_LINKER) - case R_386_RELATIVE: -#endif /* ANDROID_*_LINKER */ - COUNT_RELOC(RELOC_RELATIVE); - MARK(rel->r_offset); - if(sym){ - ERROR("%5d odd RELATIVE form...\n", pid); - return -1; - } - TRACE_TYPE(RELO, "%5d RELO RELATIVE %08x <- +%08x\n", pid, - reloc, si->base); - *((unsigned*)reloc) += si->base; - break; - -#if defined(ANDROID_X86_LINKER) - case R_386_32: - COUNT_RELOC(RELOC_RELATIVE); - MARK(rel->r_offset); - - TRACE_TYPE(RELO, "%5d RELO R_386_32 %08x <- +%08x %s\n", pid, - reloc, sym_addr, sym_name); - *((unsigned *)reloc) += (unsigned)sym_addr; - break; - - case R_386_PC32: - COUNT_RELOC(RELOC_RELATIVE); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO R_386_PC32 %08x <- " - "+%08x (%08x - %08x) %s\n", pid, reloc, - (sym_addr - reloc), sym_addr, reloc, sym_name); - *((unsigned *)reloc) += (unsigned)(sym_addr - reloc); - break; -#endif /* ANDROID_X86_LINKER */ - -#ifdef ANDROID_ARM_LINKER - case R_ARM_COPY: - COUNT_RELOC(RELOC_COPY); - MARK(rel->r_offset); - TRACE_TYPE(RELO, "%5d RELO %08x <- %d @ %08x %s\n", pid, - reloc, s->st_size, sym_addr, sym_name); - memcpy((void*)reloc, (void*)sym_addr, s->st_size); - break; -#endif /* ANDROID_ARM_LINKER */ - - default: - ERROR("%5d unknown reloc type %d @ %p (%d)\n", - pid, type, rel, (int) (rel - start)); - return -1; - } - rel++; - } - return 0; -} - -static void call_array(unsigned *ctor, int count) -{ - int n; - for(n = count; n > 0; n--){ - TRACE("[ %5d Looking at ctor *0x%08x == 0x%08x ]\n", pid, - (unsigned)ctor, (unsigned)*ctor); - void (*func)() = (void (*)()) *ctor++; - if(((int) func == 0) || ((int) func == -1)) continue; - TRACE("[ %5d Calling func @ 0x%08x ]\n", pid, (unsigned)func); - func(); - } -} - -static void call_constructors(soinfo *si) -{ - /* TODO: THE ORIGINAL CODE SEEMED TO CALL THE INIT FUNCS IN THE WRONG ORDER. - * Old order: init, init_array, preinit_array.. - * Correct order: preinit_array, init, init_array. - * Verify WHY. - */ - - if (si->flags & FLAG_EXE) { - TRACE("[ %5d Calling preinit_array @ 0x%08x [%d] for '%s' ]\n", - pid, (unsigned)si->preinit_array, si->preinit_array_count, - si->name); - call_array(si->preinit_array, si->preinit_array_count); - TRACE("[ %5d Done calling preinit_array for '%s' ]\n", pid, si->name); - } else { - if (si->preinit_array) { - ERROR("%5d Shared library '%s' has a preinit_array table @ 0x%08x." - " This is INVALID.\n", pid, si->name, - (unsigned)si->preinit_array); - } - } - - // If we have an init section, then we should call it now, to make sure - // that all the funcs in the .ctors section get run. - // Note: For ARM, we shouldn't have a .ctor section (should be empty) - // when we have an (pre)init_array section, but let's be compatible with - // old (non-eabi) binaries and try the _init (DT_INIT) anyway. - if (si->init_func) { - TRACE("[ %5d Calling init_func @ 0x%08x for '%s' ]\n", pid, - (unsigned)si->init_func, si->name); - si->init_func(); - TRACE("[ %5d Done calling init_func for '%s' ]\n", pid, si->name); - } - - if (si->init_array) { - TRACE("[ %5d Calling init_array @ 0x%08x [%d] for '%s' ]\n", pid, - (unsigned)si->init_array, si->init_array_count, si->name); - call_array(si->init_array, si->init_array_count); - TRACE("[ %5d Done calling init_array for '%s' ]\n", pid, si->name); - } -} - -static void call_destructors(soinfo *si) -{ - if (si->fini_array) { - TRACE("[ %5d Calling fini_array @ 0x%08x [%d] for '%s' ]\n", pid, - (unsigned)si->fini_array, si->fini_array_count, si->name); - call_array(si->fini_array, si->fini_array_count); - TRACE("[ %5d Done calling fini_array for '%s' ]\n", pid, si->name); - } - - // If we have an fini section, then we should call it now, to make sure - // that all the funcs in the .dtors section get run. - // Note: For ARM, we shouldn't have a .dtor section (should be empty) - // when we have an fini_array section, but let's be compatible with - // old (non-eabi) binaries and try the _fini (DT_FINI) anyway. - if (si->fini_func) { - TRACE("[ %5d Calling fini_func @ 0x%08x for '%s' ]\n", pid, - (unsigned)si->fini_func, si->name); - si->fini_func(); - TRACE("[ %5d Done calling fini_func for '%s' ]\n", pid, si->name); - } -} - -/* Force any of the closed stdin, stdout and stderr to be associated with - /dev/null. */ -static int nullify_closed_stdio (void) -{ - int dev_null, i, status; - int return_value = 0; - - dev_null = open("/dev/null", O_RDWR); - if (dev_null < 0) { - ERROR("Cannot open /dev/null.\n"); - return -1; - } - TRACE("[ %5d Opened /dev/null file-descriptor=%d]\n", pid, dev_null); - - /* If any of the stdio file descriptors is valid and not associated - with /dev/null, dup /dev/null to it. */ - for (i = 0; i < 3; i++) { - /* If it is /dev/null already, we are done. */ - if (i == dev_null) - continue; - - TRACE("[ %5d Nullifying stdio file descriptor %d]\n", pid, i); - /* The man page of fcntl does not say that fcntl(..,F_GETFL) - can be interrupted but we do this just to be safe. */ - do { - status = fcntl(i, F_GETFL); - } while (status < 0 && errno == EINTR); - - /* If file is openned, we are good. */ - if (status >= 0) - continue; - - /* The only error we allow is that the file descriptor does not - exist, in which case we dup /dev/null to it. */ - if (errno != EBADF) { - ERROR("nullify_stdio: unhandled error %s\n", strerror(errno)); - return_value = -1; - continue; - } - - /* Try dupping /dev/null to this stdio file descriptor and - repeat if there is a signal. Note that any errors in closing - the stdio descriptor are lost. */ - do { - status = dup2(dev_null, i); - } while (status < 0 && errno == EINTR); - - if (status < 0) { - ERROR("nullify_stdio: dup2 error %s\n", strerror(errno)); - return_value = -1; - continue; - } - } - - /* If /dev/null is not one of the stdio file descriptors, close it. */ - if (dev_null > 2) { - TRACE("[ %5d Closing /dev/null file-descriptor=%d]\n", pid, dev_null); - do { - status = close(dev_null); - } while (status < 0 && errno == EINTR); - - if (status < 0) { - ERROR("nullify_stdio: close error %s\n", strerror(errno)); - return_value = -1; - } - } - - return return_value; -} - -static int link_image(soinfo *si, unsigned wr_offset) -{ - unsigned *d; - Elf32_Phdr *phdr = si->phdr; - int phnum = si->phnum; - - INFO("[ %5d linking %s ]\n", pid, si->name); - DEBUG("%5d si->base = 0x%08x si->flags = 0x%08x\n", pid, - si->base, si->flags); - - if (si->flags & FLAG_EXE) { - /* Locate the needed program segments (DYNAMIC/ARM_EXIDX) for - * linkage info if this is the executable. If this was a - * dynamic lib, that would have been done at load time. - * - * TODO: It's unfortunate that small pieces of this are - * repeated from the load_library routine. Refactor this just - * slightly to reuse these bits. - */ - si->size = 0; - for(; phnum > 0; --phnum, ++phdr) { -#ifdef ANDROID_ARM_LINKER - if(phdr->p_type == PT_ARM_EXIDX) { - /* exidx entries (used for stack unwinding) are 8 bytes each. - */ - si->ARM_exidx = (unsigned *)phdr->p_vaddr; - si->ARM_exidx_count = phdr->p_memsz / 8; - } -#endif - if (phdr->p_type == PT_LOAD) { - /* For the executable, we use the si->size field only in - dl_unwind_find_exidx(), so the meaning of si->size - is not the size of the executable; it is the last - virtual address of the loadable part of the executable; - since si->base == 0 for an executable, we use the - range [0, si->size) to determine whether a PC value - falls within the executable section. Of course, if - a value is below phdr->p_vaddr, it's not in the - executable section, but a) we shouldn't be asking for - such a value anyway, and b) if we have to provide - an EXIDX for such a value, then the executable's - EXIDX is probably the better choice. - */ - DEBUG_DUMP_PHDR(phdr, "PT_LOAD", pid); - if (phdr->p_vaddr + phdr->p_memsz > si->size) - si->size = phdr->p_vaddr + phdr->p_memsz; - /* try to remember what range of addresses should be write - * protected */ - if (!(phdr->p_flags & PF_W)) { - unsigned _end; - - if (phdr->p_vaddr < si->wrprotect_start) - si->wrprotect_start = phdr->p_vaddr; - _end = (((phdr->p_vaddr + phdr->p_memsz + PAGE_SIZE - 1) & - (~PAGE_MASK))); - if (_end > si->wrprotect_end) - si->wrprotect_end = _end; - } - } else if (phdr->p_type == PT_DYNAMIC) { - if (si->dynamic != (unsigned *)-1) { - ERROR("%5d multiple PT_DYNAMIC segments found in '%s'. " - "Segment at 0x%08x, previously one found at 0x%08x\n", - pid, si->name, si->base + phdr->p_vaddr, - (unsigned)si->dynamic); - goto fail; - } - DEBUG_DUMP_PHDR(phdr, "PT_DYNAMIC", pid); - si->dynamic = (unsigned *) (si->base + phdr->p_vaddr); - } - } - } - - if (si->dynamic == (unsigned *)-1) { - ERROR("%5d missing PT_DYNAMIC?!\n", pid); - goto fail; - } - - DEBUG("%5d dynamic = %p\n", pid, si->dynamic); - - /* extract useful information from dynamic section */ - for(d = si->dynamic; *d; d++){ - DEBUG("%5d d = %p, d[0] = 0x%08x d[1] = 0x%08x\n", pid, d, d[0], d[1]); - switch(*d++){ - case DT_HASH: - si->nbucket = ((unsigned *) (si->base + *d))[0]; - si->nchain = ((unsigned *) (si->base + *d))[1]; - si->bucket = (unsigned *) (si->base + *d + 8); - si->chain = (unsigned *) (si->base + *d + 8 + si->nbucket * 4); - break; - case DT_STRTAB: - si->strtab = (const char *) (si->base + *d); - break; - case DT_SYMTAB: - si->symtab = (Elf32_Sym *) (si->base + *d); - break; - case DT_PLTREL: - if(*d != DT_REL) { - ERROR("DT_RELA not supported\n"); - goto fail; - } - break; - case DT_JMPREL: - si->plt_rel = (Elf32_Rel*) (si->base + *d); - break; - case DT_PLTRELSZ: - si->plt_rel_count = *d / 8; - break; - case DT_REL: - si->rel = (Elf32_Rel*) (si->base + *d); - break; - case DT_RELSZ: - si->rel_count = *d / 8; - break; - case DT_PLTGOT: - /* Save this in case we decide to do lazy binding. We don't yet. */ - si->plt_got = (unsigned *)(si->base + *d); - break; - case DT_DEBUG: - // Set the DT_DEBUG entry to the addres of _r_debug for GDB - *d = (int) &_r_debug; - break; - case DT_RELA: - ERROR("%5d DT_RELA not supported\n", pid); - goto fail; - case DT_INIT: - si->init_func = (void (*)(void))(si->base + *d); - DEBUG("%5d %s constructors (init func) found at %p\n", - pid, si->name, si->init_func); - break; - case DT_FINI: - si->fini_func = (void (*)(void))(si->base + *d); - DEBUG("%5d %s destructors (fini func) found at %p\n", - pid, si->name, si->fini_func); - break; - case DT_INIT_ARRAY: - si->init_array = (unsigned *)(si->base + *d); - DEBUG("%5d %s constructors (init_array) found at %p\n", - pid, si->name, si->init_array); - break; - case DT_INIT_ARRAYSZ: - si->init_array_count = ((unsigned)*d) / sizeof(Elf32_Addr); - break; - case DT_FINI_ARRAY: - si->fini_array = (unsigned *)(si->base + *d); - DEBUG("%5d %s destructors (fini_array) found at %p\n", - pid, si->name, si->fini_array); - break; - case DT_FINI_ARRAYSZ: - si->fini_array_count = ((unsigned)*d) / sizeof(Elf32_Addr); - break; - case DT_PREINIT_ARRAY: - si->preinit_array = (unsigned *)(si->base + *d); - DEBUG("%5d %s constructors (preinit_array) found at %p\n", - pid, si->name, si->preinit_array); - break; - case DT_PREINIT_ARRAYSZ: - si->preinit_array_count = ((unsigned)*d) / sizeof(Elf32_Addr); - break; - case DT_TEXTREL: - /* TODO: make use of this. */ - /* this means that we might have to write into where the text - * segment was loaded during relocation... Do something with - * it. - */ - DEBUG("%5d Text segment should be writable during relocation.\n", - pid); - break; - } - } - - DEBUG("%5d si->base = 0x%08x, si->strtab = %p, si->symtab = %p\n", - pid, si->base, si->strtab, si->symtab); - - if((si->strtab == 0) || (si->symtab == 0)) { - ERROR("%5d missing essential tables\n", pid); - goto fail; - } - - for(d = si->dynamic; *d; d += 2) { - if(d[0] == DT_NEEDED){ - DEBUG("%5d %s needs %s\n", pid, si->name, si->strtab + d[1]); - soinfo *lsi = find_library(si->strtab + d[1]); - if(lsi == 0) { - ERROR("%5d could not load '%s'\n", pid, si->strtab + d[1]); - goto fail; - } - lsi->refcount++; - } - } - - if(si->plt_rel) { - DEBUG("[ %5d relocating %s plt ]\n", pid, si->name ); - if(reloc_library(si, si->plt_rel, si->plt_rel_count)) - goto fail; - } - if(si->rel) { - DEBUG("[ %5d relocating %s ]\n", pid, si->name ); - if(reloc_library(si, si->rel, si->rel_count)) - goto fail; - } - - si->flags |= FLAG_LINKED; - DEBUG("[ %5d finished linking %s ]\n", pid, si->name); - -#if 0 - /* This is the way that the old dynamic linker did protection of - * non-writable areas. It would scan section headers and find where - * .text ended (rather where .data/.bss began) and assume that this is - * the upper range of the non-writable area. This is too coarse, - * and is kept here for reference until we fully move away from single - * segment elf objects. See the code in get_wr_offset (also #if'd 0) - * that made this possible. - */ - if(wr_offset < 0xffffffff){ - mprotect((void*) si->base, wr_offset, PROT_READ | PROT_EXEC); - } -#else - /* TODO: Verify that this does the right thing in all cases, as it - * presently probably does not. It is possible that an ELF image will - * come with multiple read-only segments. What we ought to do is scan - * the program headers again and mprotect all the read-only segments. - * To prevent re-scanning the program header, we would have to build a - * list of loadable segments in si, and then scan that instead. */ - if (si->wrprotect_start != 0xffffffff && si->wrprotect_end != 0) { - mprotect((void *)si->wrprotect_start, - si->wrprotect_end - si->wrprotect_start, - PROT_READ | PROT_EXEC); - } -#endif - - /* If this is a SET?ID program, dup /dev/null to opened stdin, - stdout and stderr to close a security hole described in: - - ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-02:23.stdio.asc - - */ - if (getuid() != geteuid() || getgid() != getegid()) - nullify_closed_stdio (); - call_constructors(si); - notify_gdb_of_load(si); - return 0; - -fail: - ERROR("failed to link %s\n", si->name); - si->flags |= FLAG_ERROR; - return -1; -} - -int main(int argc, char **argv) -{ - return 0; -} - -#define ANDROID_TLS_SLOTS BIONIC_TLS_SLOTS - -static void * __tls_area[ANDROID_TLS_SLOTS]; - -unsigned __linker_init(unsigned **elfdata) -{ - static soinfo linker_soinfo; - - int argc = (int) *elfdata; - char **argv = (char**) (elfdata + 1); - unsigned *vecs = (unsigned*) (argv + argc + 1); - soinfo *si; - struct link_map * map; - - pid = getpid(); - -#if TIMING - struct timeval t0, t1; - gettimeofday(&t0, 0); -#endif - - __set_tls(__tls_area); - ((unsigned *)__get_tls())[TLS_SLOT_THREAD_ID] = gettid(); - - debugger_init(); - - /* skip past the environment */ - while(vecs[0] != 0) { - if(!strncmp((char*) vecs[0], "DEBUG=", 6)) { - debug_verbosity = atoi(((char*) vecs[0]) + 6); - } - vecs++; - } - vecs++; - - INFO("[ android linker & debugger ]\n"); - DEBUG("%5d elfdata @ 0x%08x\n", pid, (unsigned)elfdata); - - si = alloc_info(argv[0]); - if(si == 0) { - exit(-1); - } - - /* bootstrap the link map, the main exe always needs to be first */ - si->flags |= FLAG_EXE; - map = &(si->linkmap); - - map->l_addr = 0; - map->l_name = argv[0]; - map->l_prev = NULL; - map->l_next = NULL; - - _r_debug.r_map = map; - r_debug_tail = map; - - /* gdb expects the linker to be in the debug shared object list, - * and we need to make sure that the reported load address is zero. - * Without this, gdb gets the wrong idea of where rtld_db_dlactivity() - * is. Don't use alloc_info(), because the linker shouldn't - * be on the soinfo list. - */ - strcpy((char*) linker_soinfo.name, "/system/bin/linker"); - linker_soinfo.flags = 0; - linker_soinfo.base = 0; // This is the important part; must be zero. - insert_soinfo_into_debug_map(&linker_soinfo); - - /* extract information passed from the kernel */ - while(vecs[0] != 0){ - switch(vecs[0]){ - case AT_PHDR: - si->phdr = (Elf32_Phdr*) vecs[1]; - break; - case AT_PHNUM: - si->phnum = (int) vecs[1]; - break; - case AT_ENTRY: - si->entry = vecs[1]; - break; - } - vecs += 2; - } - - si->base = 0; - si->dynamic = (unsigned *)-1; - si->wrprotect_start = 0xffffffff; - si->wrprotect_end = 0; - - if(link_image(si, 0)){ - ERROR("CANNOT LINK EXECUTABLE '%s'\n", argv[0]); - exit(-1); - } - -#if TIMING - gettimeofday(&t1,NULL); - PRINT("LINKER TIME: %s: %d microseconds\n", argv[0], (int) ( - (((long long)t1.tv_sec * 1000000LL) + (long long)t1.tv_usec) - - (((long long)t0.tv_sec * 1000000LL) + (long long)t0.tv_usec) - )); -#endif -#if STATS - PRINT("RELO STATS: %s: %d abs, %d rel, %d copy, %d symbol\n", argv[0], - linker_stats.reloc[RELOC_ABSOLUTE], - linker_stats.reloc[RELOC_RELATIVE], - linker_stats.reloc[RELOC_COPY], - linker_stats.reloc[RELOC_SYMBOL]); -#endif -#if COUNT_PAGES - { - unsigned n; - unsigned i; - unsigned count = 0; - for(n = 0; n < 4096; n++){ - if(bitmask[n]){ - unsigned x = bitmask[n]; - for(i = 0; i < 8; i++){ - if(x & 1) count++; - x >>= 1; - } - } - } - PRINT("PAGES MODIFIED: %s: %d (%dKB)\n", argv[0], count, count * 4); - } -#endif - -#if TIMING || STATS || COUNT_PAGES - fflush(stdout); -#endif - - TRACE("[ %5d Ready to execute '%s' @ 0x%08x ]\n", pid, si->name, - si->entry); - return si->entry; -} |