diff --git a/sys/kern/link_elf.c b/sys/kern/link_elf.c index 5f0649d7540c..8e1495acee2b 100644 --- a/sys/kern/link_elf.c +++ b/sys/kern/link_elf.c @@ -1,1987 +1,1984 @@ /*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * * Copyright (c) 1998-2000 Doug Rabson * 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 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 AUTHOR 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 __FBSDID("$FreeBSD$"); #include "opt_ddb.h" #include "opt_gdb.h" #include #include #include #include #include #ifdef SPARSE_MAPPING #include #endif #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef SPARSE_MAPPING #include #include #include #endif #include #include #include #include "linker_if.h" #define MAXSEGS 4 typedef struct elf_file { struct linker_file lf; /* Common fields */ int preloaded; /* Was file pre-loaded */ caddr_t address; /* Relocation address */ #ifdef SPARSE_MAPPING vm_object_t object; /* VM object to hold file pages */ #endif Elf_Dyn *dynamic; /* Symbol table etc. */ Elf_Hashelt nbuckets; /* DT_HASH info */ Elf_Hashelt nchains; const Elf_Hashelt *buckets; const Elf_Hashelt *chains; caddr_t hash; caddr_t strtab; /* DT_STRTAB */ int strsz; /* DT_STRSZ */ const Elf_Sym *symtab; /* DT_SYMTAB */ Elf_Addr *got; /* DT_PLTGOT */ const Elf_Rel *pltrel; /* DT_JMPREL */ int pltrelsize; /* DT_PLTRELSZ */ const Elf_Rela *pltrela; /* DT_JMPREL */ int pltrelasize; /* DT_PLTRELSZ */ const Elf_Rel *rel; /* DT_REL */ int relsize; /* DT_RELSZ */ const Elf_Rela *rela; /* DT_RELA */ int relasize; /* DT_RELASZ */ caddr_t modptr; const Elf_Sym *ddbsymtab; /* The symbol table we are using */ long ddbsymcnt; /* Number of symbols */ caddr_t ddbstrtab; /* String table */ long ddbstrcnt; /* number of bytes in string table */ caddr_t symbase; /* malloc'ed symbold base */ caddr_t strbase; /* malloc'ed string base */ caddr_t ctftab; /* CTF table */ long ctfcnt; /* number of bytes in CTF table */ caddr_t ctfoff; /* CTF offset table */ caddr_t typoff; /* Type offset table */ long typlen; /* Number of type entries. */ Elf_Addr pcpu_start; /* Pre-relocation pcpu set start. */ Elf_Addr pcpu_stop; /* Pre-relocation pcpu set stop. */ Elf_Addr pcpu_base; /* Relocated pcpu set address. */ #ifdef VIMAGE Elf_Addr vnet_start; /* Pre-relocation vnet set start. */ Elf_Addr vnet_stop; /* Pre-relocation vnet set stop. */ Elf_Addr vnet_base; /* Relocated vnet set address. */ #endif #ifdef GDB struct link_map gdb; /* hooks for gdb */ #endif } *elf_file_t; struct elf_set { Elf_Addr es_start; Elf_Addr es_stop; Elf_Addr es_base; TAILQ_ENTRY(elf_set) es_link; }; TAILQ_HEAD(elf_set_head, elf_set); #include static int link_elf_link_common_finish(linker_file_t); static int link_elf_link_preload(linker_class_t cls, const char *, linker_file_t *); static int link_elf_link_preload_finish(linker_file_t); static int link_elf_load_file(linker_class_t, const char *, linker_file_t *); static int link_elf_lookup_symbol(linker_file_t, const char *, c_linker_sym_t *); static int link_elf_lookup_debug_symbol(linker_file_t, const char *, c_linker_sym_t *); static int link_elf_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t *); static int link_elf_debug_symbol_values(linker_file_t, c_linker_sym_t, linker_symval_t*); static int link_elf_search_symbol(linker_file_t, caddr_t, c_linker_sym_t *, long *); static void link_elf_unload_file(linker_file_t); static void link_elf_unload_preload(linker_file_t); static int link_elf_lookup_set(linker_file_t, const char *, void ***, void ***, int *); static int link_elf_each_function_name(linker_file_t, int (*)(const char *, void *), void *); static int link_elf_each_function_nameval(linker_file_t, linker_function_nameval_callback_t, void *); static void link_elf_reloc_local(linker_file_t); static long link_elf_symtab_get(linker_file_t, const Elf_Sym **); static long link_elf_strtab_get(linker_file_t, caddr_t *); static int elf_lookup(linker_file_t, Elf_Size, int, Elf_Addr *); static kobj_method_t link_elf_methods[] = { KOBJMETHOD(linker_lookup_symbol, link_elf_lookup_symbol), KOBJMETHOD(linker_lookup_debug_symbol, link_elf_lookup_debug_symbol), KOBJMETHOD(linker_symbol_values, link_elf_symbol_values), KOBJMETHOD(linker_debug_symbol_values, link_elf_debug_symbol_values), KOBJMETHOD(linker_search_symbol, link_elf_search_symbol), KOBJMETHOD(linker_unload, link_elf_unload_file), KOBJMETHOD(linker_load_file, link_elf_load_file), KOBJMETHOD(linker_link_preload, link_elf_link_preload), KOBJMETHOD(linker_link_preload_finish, link_elf_link_preload_finish), KOBJMETHOD(linker_lookup_set, link_elf_lookup_set), KOBJMETHOD(linker_each_function_name, link_elf_each_function_name), KOBJMETHOD(linker_each_function_nameval, link_elf_each_function_nameval), KOBJMETHOD(linker_ctf_get, link_elf_ctf_get), KOBJMETHOD(linker_symtab_get, link_elf_symtab_get), KOBJMETHOD(linker_strtab_get, link_elf_strtab_get), KOBJMETHOD_END }; static struct linker_class link_elf_class = { #if ELF_TARG_CLASS == ELFCLASS32 "elf32", #else "elf64", #endif link_elf_methods, sizeof(struct elf_file) }; static bool link_elf_leak_locals = true; SYSCTL_BOOL(_debug, OID_AUTO, link_elf_leak_locals, CTLFLAG_RWTUN, &link_elf_leak_locals, 0, "Allow local symbols to participate in global module symbol resolution"); typedef int (*elf_reloc_fn)(linker_file_t lf, Elf_Addr relocbase, const void *data, int type, elf_lookup_fn lookup); static int parse_dynamic(elf_file_t); static int relocate_file(elf_file_t); static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, bool ifuncs); static int link_elf_preload_parse_symbols(elf_file_t); static struct elf_set_head set_pcpu_list; #ifdef VIMAGE static struct elf_set_head set_vnet_list; #endif static void elf_set_add(struct elf_set_head *list, Elf_Addr start, Elf_Addr stop, Elf_Addr base) { struct elf_set *set, *iter; set = malloc(sizeof(*set), M_LINKER, M_WAITOK); set->es_start = start; set->es_stop = stop; set->es_base = base; TAILQ_FOREACH(iter, list, es_link) { KASSERT((set->es_start < iter->es_start && set->es_stop < iter->es_stop) || (set->es_start > iter->es_start && set->es_stop > iter->es_stop), ("linker sets intersection: to insert: 0x%jx-0x%jx; inserted: 0x%jx-0x%jx", (uintmax_t)set->es_start, (uintmax_t)set->es_stop, (uintmax_t)iter->es_start, (uintmax_t)iter->es_stop)); if (iter->es_start > set->es_start) { TAILQ_INSERT_BEFORE(iter, set, es_link); break; } } if (iter == NULL) TAILQ_INSERT_TAIL(list, set, es_link); } static int elf_set_find(struct elf_set_head *list, Elf_Addr addr, Elf_Addr *start, Elf_Addr *base) { struct elf_set *set; TAILQ_FOREACH(set, list, es_link) { if (addr < set->es_start) return (0); if (addr < set->es_stop) { *start = set->es_start; *base = set->es_base; return (1); } } return (0); } static void elf_set_delete(struct elf_set_head *list, Elf_Addr start) { struct elf_set *set; TAILQ_FOREACH(set, list, es_link) { if (start < set->es_start) break; if (start == set->es_start) { TAILQ_REMOVE(list, set, es_link); free(set, M_LINKER); return; } } KASSERT(0, ("deleting unknown linker set (start = 0x%jx)", (uintmax_t)start)); } #ifdef GDB static void r_debug_state(struct r_debug *, struct link_map *); /* * A list of loaded modules for GDB to use for loading symbols. */ struct r_debug r_debug; #define GDB_STATE(s) do { \ r_debug.r_state = s; r_debug_state(NULL, NULL); \ } while (0) /* * Function for the debugger to set a breakpoint on to gain control. */ static void r_debug_state(struct r_debug *dummy_one __unused, struct link_map *dummy_two __unused) { } static void link_elf_add_gdb(struct link_map *l) { struct link_map *prev; l->l_next = NULL; if (r_debug.r_map == NULL) { /* Add first. */ l->l_prev = NULL; r_debug.r_map = l; } else { /* Append to list. */ for (prev = r_debug.r_map; prev->l_next != NULL; prev = prev->l_next) ; l->l_prev = prev; prev->l_next = l; } } static void link_elf_delete_gdb(struct link_map *l) { if (l->l_prev == NULL) { /* Remove first. */ if ((r_debug.r_map = l->l_next) != NULL) l->l_next->l_prev = NULL; } else { /* Remove any but first. */ if ((l->l_prev->l_next = l->l_next) != NULL) l->l_next->l_prev = l->l_prev; } } #endif /* GDB */ /* * The kernel symbol table starts here. */ extern struct _dynamic _DYNAMIC; static void link_elf_error(const char *filename, const char *s) { if (filename == NULL) printf("kldload: %s\n", s); else printf("kldload: %s: %s\n", filename, s); } static void link_elf_invoke_ctors(caddr_t addr, size_t size) { void (**ctor)(void); size_t i, cnt; if (addr == NULL || size == 0) return; cnt = size / sizeof(*ctor); ctor = (void *)addr; for (i = 0; i < cnt; i++) { if (ctor[i] != NULL) (*ctor[i])(); } } /* * Actions performed after linking/loading both the preloaded kernel and any * modules; whether preloaded or dynamicly loaded. */ static int link_elf_link_common_finish(linker_file_t lf) { #ifdef GDB elf_file_t ef = (elf_file_t)lf; char *newfilename; #endif int error; /* Notify MD code that a module is being loaded. */ error = elf_cpu_load_file(lf); if (error != 0) return (error); #ifdef GDB GDB_STATE(RT_ADD); ef->gdb.l_addr = lf->address; newfilename = malloc(strlen(lf->filename) + 1, M_LINKER, M_WAITOK); strcpy(newfilename, lf->filename); ef->gdb.l_name = newfilename; ef->gdb.l_ld = ef->dynamic; link_elf_add_gdb(&ef->gdb); GDB_STATE(RT_CONSISTENT); #endif /* Invoke .ctors */ link_elf_invoke_ctors(lf->ctors_addr, lf->ctors_size); return (0); } #ifdef RELOCATABLE_KERNEL /* * __startkernel and __endkernel are symbols set up as relocation canaries. * * They are defined in locore to reference linker script symbols at the * beginning and end of the LOAD area. This has the desired side effect of * giving us variables that have relative relocations pointing at them, so * relocation of the kernel object will cause the variables to be updated * automatically by the runtime linker when we initialize. * * There are two main reasons to relocate the kernel: * 1) If the loader needed to load the kernel at an alternate load address. * 2) If the kernel is switching address spaces on machines like POWER9 * under Radix where the high bits of the effective address are used to * differentiate between hypervisor, host, guest, and problem state. */ extern vm_offset_t __startkernel, __endkernel; #endif static unsigned long kern_relbase = KERNBASE; SYSCTL_ULONG(_kern, OID_AUTO, base_address, CTLFLAG_RD, SYSCTL_NULL_ULONG_PTR, KERNBASE, "Kernel base address"); SYSCTL_ULONG(_kern, OID_AUTO, relbase_address, CTLFLAG_RD, &kern_relbase, 0, "Kernel relocated base address"); static void link_elf_init(void* arg) { Elf_Dyn *dp; Elf_Addr *ctors_addrp; Elf_Size *ctors_sizep; caddr_t modptr, baseptr, sizeptr; elf_file_t ef; const char *modname; linker_add_class(&link_elf_class); dp = (Elf_Dyn *)&_DYNAMIC; modname = NULL; modptr = preload_search_by_type("elf" __XSTRING(__ELF_WORD_SIZE) " kernel"); if (modptr == NULL) modptr = preload_search_by_type("elf kernel"); modname = (char *)preload_search_info(modptr, MODINFO_NAME); if (modname == NULL) modname = "kernel"; linker_kernel_file = linker_make_file(modname, &link_elf_class); if (linker_kernel_file == NULL) panic("%s: Can't create linker structures for kernel", __func__); ef = (elf_file_t) linker_kernel_file; ef->preloaded = 1; #ifdef RELOCATABLE_KERNEL /* Compute relative displacement */ ef->address = (caddr_t) (__startkernel - KERNBASE); #else ef->address = 0; #endif #ifdef SPARSE_MAPPING ef->object = NULL; #endif ef->dynamic = dp; if (dp != NULL) parse_dynamic(ef); #ifdef RELOCATABLE_KERNEL linker_kernel_file->address = (caddr_t)__startkernel; linker_kernel_file->size = (intptr_t)(__endkernel - __startkernel); kern_relbase = (unsigned long)__startkernel; #else linker_kernel_file->address += KERNBASE; linker_kernel_file->size = -(intptr_t)linker_kernel_file->address; #endif if (modptr != NULL) { ef->modptr = modptr; baseptr = preload_search_info(modptr, MODINFO_ADDR); if (baseptr != NULL) linker_kernel_file->address = *(caddr_t *)baseptr; sizeptr = preload_search_info(modptr, MODINFO_SIZE); if (sizeptr != NULL) linker_kernel_file->size = *(size_t *)sizeptr; ctors_addrp = (Elf_Addr *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_CTORS_ADDR); ctors_sizep = (Elf_Size *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_CTORS_SIZE); if (ctors_addrp != NULL && ctors_sizep != NULL) { linker_kernel_file->ctors_addr = ef->address + *ctors_addrp; linker_kernel_file->ctors_size = *ctors_sizep; } } (void)link_elf_preload_parse_symbols(ef); #ifdef GDB r_debug.r_map = NULL; r_debug.r_brk = r_debug_state; r_debug.r_state = RT_CONSISTENT; #endif (void)link_elf_link_common_finish(linker_kernel_file); linker_kernel_file->flags |= LINKER_FILE_LINKED; TAILQ_INIT(&set_pcpu_list); #ifdef VIMAGE TAILQ_INIT(&set_vnet_list); #endif } SYSINIT(link_elf, SI_SUB_KLD, SI_ORDER_THIRD, link_elf_init, NULL); static int link_elf_preload_parse_symbols(elf_file_t ef) { caddr_t pointer; caddr_t ssym, esym, base; caddr_t strtab; int strcnt; Elf_Sym *symtab; int symcnt; if (ef->modptr == NULL) return (0); pointer = preload_search_info(ef->modptr, MODINFO_METADATA | MODINFOMD_SSYM); if (pointer == NULL) return (0); ssym = *(caddr_t *)pointer; pointer = preload_search_info(ef->modptr, MODINFO_METADATA | MODINFOMD_ESYM); if (pointer == NULL) return (0); esym = *(caddr_t *)pointer; base = ssym; symcnt = *(long *)base; base += sizeof(long); symtab = (Elf_Sym *)base; base += roundup(symcnt, sizeof(long)); if (base > esym || base < ssym) { printf("Symbols are corrupt!\n"); return (EINVAL); } strcnt = *(long *)base; base += sizeof(long); strtab = base; base += roundup(strcnt, sizeof(long)); if (base > esym || base < ssym) { printf("Symbols are corrupt!\n"); return (EINVAL); } ef->ddbsymtab = symtab; ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); ef->ddbstrtab = strtab; ef->ddbstrcnt = strcnt; return (0); } static int parse_dynamic(elf_file_t ef) { Elf_Dyn *dp; int plttype = DT_REL; for (dp = ef->dynamic; dp->d_tag != DT_NULL; dp++) { switch (dp->d_tag) { case DT_HASH: { /* From src/libexec/rtld-elf/rtld.c */ const Elf_Hashelt *hashtab = (const Elf_Hashelt *) (ef->address + dp->d_un.d_ptr); ef->nbuckets = hashtab[0]; ef->nchains = hashtab[1]; ef->buckets = hashtab + 2; ef->chains = ef->buckets + ef->nbuckets; break; } case DT_STRTAB: ef->strtab = (caddr_t) (ef->address + dp->d_un.d_ptr); break; case DT_STRSZ: ef->strsz = dp->d_un.d_val; break; case DT_SYMTAB: ef->symtab = (Elf_Sym*) (ef->address + dp->d_un.d_ptr); break; case DT_SYMENT: if (dp->d_un.d_val != sizeof(Elf_Sym)) return (ENOEXEC); break; case DT_PLTGOT: ef->got = (Elf_Addr *) (ef->address + dp->d_un.d_ptr); break; case DT_REL: ef->rel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); break; case DT_RELSZ: ef->relsize = dp->d_un.d_val; break; case DT_RELENT: if (dp->d_un.d_val != sizeof(Elf_Rel)) return (ENOEXEC); break; case DT_JMPREL: ef->pltrel = (const Elf_Rel *) (ef->address + dp->d_un.d_ptr); break; case DT_PLTRELSZ: ef->pltrelsize = dp->d_un.d_val; break; case DT_RELA: ef->rela = (const Elf_Rela *) (ef->address + dp->d_un.d_ptr); break; case DT_RELASZ: ef->relasize = dp->d_un.d_val; break; case DT_RELAENT: if (dp->d_un.d_val != sizeof(Elf_Rela)) return (ENOEXEC); break; case DT_PLTREL: plttype = dp->d_un.d_val; if (plttype != DT_REL && plttype != DT_RELA) return (ENOEXEC); break; #ifdef GDB case DT_DEBUG: dp->d_un.d_ptr = (Elf_Addr)&r_debug; break; #endif } } if (plttype == DT_RELA) { ef->pltrela = (const Elf_Rela *)ef->pltrel; ef->pltrel = NULL; ef->pltrelasize = ef->pltrelsize; ef->pltrelsize = 0; } ef->ddbsymtab = ef->symtab; ef->ddbsymcnt = ef->nchains; ef->ddbstrtab = ef->strtab; ef->ddbstrcnt = ef->strsz; return elf_cpu_parse_dynamic(ef->address, ef->dynamic); } #define LS_PADDING 0x90909090 static int parse_dpcpu(elf_file_t ef) { int error, size; #if defined(__i386__) uint32_t pad; #endif ef->pcpu_start = 0; ef->pcpu_stop = 0; error = link_elf_lookup_set(&ef->lf, "pcpu", (void ***)&ef->pcpu_start, (void ***)&ef->pcpu_stop, NULL); /* Error just means there is no pcpu set to relocate. */ if (error != 0) return (0); size = (uintptr_t)ef->pcpu_stop - (uintptr_t)ef->pcpu_start; /* Empty set? */ if (size < 1) return (0); #if defined(__i386__) /* In case we do find __start/stop_set_ symbols double-check. */ if (size < 4) { uprintf("Kernel module '%s' must be recompiled with " "linker script\n", ef->lf.pathname); return (ENOEXEC); } /* Padding from linker-script correct? */ pad = *(uint32_t *)((uintptr_t)ef->pcpu_stop - sizeof(pad)); if (pad != LS_PADDING) { uprintf("Kernel module '%s' must be recompiled with " "linker script, invalid padding %#04x (%#04x)\n", ef->lf.pathname, pad, LS_PADDING); return (ENOEXEC); } /* If we only have valid padding, nothing to do. */ if (size == 4) return (0); #endif /* * Allocate space in the primary pcpu area. Copy in our * initialization from the data section and then initialize * all per-cpu storage from that. */ ef->pcpu_base = (Elf_Addr)(uintptr_t)dpcpu_alloc(size); if (ef->pcpu_base == 0) { printf("%s: pcpu module space is out of space; " "cannot allocate %d for %s\n", __func__, size, ef->lf.pathname); return (ENOSPC); } memcpy((void *)ef->pcpu_base, (void *)ef->pcpu_start, size); dpcpu_copy((void *)ef->pcpu_base, size); elf_set_add(&set_pcpu_list, ef->pcpu_start, ef->pcpu_stop, ef->pcpu_base); return (0); } #ifdef VIMAGE static int parse_vnet(elf_file_t ef) { int error, size; #if defined(__i386__) uint32_t pad; #endif ef->vnet_start = 0; ef->vnet_stop = 0; error = link_elf_lookup_set(&ef->lf, "vnet", (void ***)&ef->vnet_start, (void ***)&ef->vnet_stop, NULL); /* Error just means there is no vnet data set to relocate. */ if (error != 0) return (0); size = (uintptr_t)ef->vnet_stop - (uintptr_t)ef->vnet_start; /* Empty set? */ if (size < 1) return (0); #if defined(__i386__) /* In case we do find __start/stop_set_ symbols double-check. */ if (size < 4) { uprintf("Kernel module '%s' must be recompiled with " "linker script\n", ef->lf.pathname); return (ENOEXEC); } /* Padding from linker-script correct? */ pad = *(uint32_t *)((uintptr_t)ef->vnet_stop - sizeof(pad)); if (pad != LS_PADDING) { uprintf("Kernel module '%s' must be recompiled with " "linker script, invalid padding %#04x (%#04x)\n", ef->lf.pathname, pad, LS_PADDING); return (ENOEXEC); } /* If we only have valid padding, nothing to do. */ if (size == 4) return (0); #endif /* * Allocate space in the primary vnet area. Copy in our * initialization from the data section and then initialize * all per-vnet storage from that. */ ef->vnet_base = (Elf_Addr)(uintptr_t)vnet_data_alloc(size); if (ef->vnet_base == 0) { printf("%s: vnet module space is out of space; " "cannot allocate %d for %s\n", __func__, size, ef->lf.pathname); return (ENOSPC); } memcpy((void *)ef->vnet_base, (void *)ef->vnet_start, size); vnet_data_copy((void *)ef->vnet_base, size); elf_set_add(&set_vnet_list, ef->vnet_start, ef->vnet_stop, ef->vnet_base); return (0); } #endif #undef LS_PADDING /* * Apply the specified protection to the loadable segments of a preloaded linker * file. */ static int preload_protect(elf_file_t ef, vm_prot_t prot) { #if defined(__aarch64__) || defined(__amd64__) Elf_Ehdr *hdr; Elf_Phdr *phdr, *phlimit; vm_prot_t nprot; int error; error = 0; hdr = (Elf_Ehdr *)ef->address; phdr = (Elf_Phdr *)(ef->address + hdr->e_phoff); phlimit = phdr + hdr->e_phnum; for (; phdr < phlimit; phdr++) { if (phdr->p_type != PT_LOAD) continue; nprot = prot | VM_PROT_READ; if ((phdr->p_flags & PF_W) != 0) nprot |= VM_PROT_WRITE; if ((phdr->p_flags & PF_X) != 0) nprot |= VM_PROT_EXECUTE; error = pmap_change_prot((vm_offset_t)ef->address + phdr->p_vaddr, round_page(phdr->p_memsz), nprot); if (error != 0) break; } return (error); #else return (0); #endif } #ifdef __arm__ /* * Locate the ARM exception/unwind table info for DDB and stack(9) use by * searching for the section header that describes it. There may be no unwind * info, for example in a module containing only data. */ static void link_elf_locate_exidx(linker_file_t lf, Elf_Shdr *shdr, int nhdr) { int i; for (i = 0; i < nhdr; i++) { if (shdr[i].sh_type == SHT_ARM_EXIDX) { lf->exidx_addr = shdr[i].sh_addr + lf->address; lf->exidx_size = shdr[i].sh_size; break; } } } /* * Locate the section headers metadata in a preloaded module, then use it to * locate the exception/unwind table in the module. The size of the metadata * block is stored in a uint32 word immediately before the data itself, and a * comment in preload_search_info() says it is safe to rely on that. */ static void link_elf_locate_exidx_preload(struct linker_file *lf, caddr_t modptr) { uint32_t *modinfo; Elf_Shdr *shdr; uint32_t nhdr; modinfo = (uint32_t *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_SHDR); if (modinfo != NULL) { shdr = (Elf_Shdr *)modinfo; nhdr = modinfo[-1] / sizeof(Elf_Shdr); link_elf_locate_exidx(lf, shdr, nhdr); } } #endif /* __arm__ */ static int link_elf_link_preload(linker_class_t cls, const char *filename, linker_file_t *result) { Elf_Addr *ctors_addrp; Elf_Size *ctors_sizep; caddr_t modptr, baseptr, sizeptr, dynptr; char *type; elf_file_t ef; linker_file_t lf; int error; vm_offset_t dp; /* Look to see if we have the file preloaded */ modptr = preload_search_by_name(filename); if (modptr == NULL) return (ENOENT); type = (char *)preload_search_info(modptr, MODINFO_TYPE); baseptr = preload_search_info(modptr, MODINFO_ADDR); sizeptr = preload_search_info(modptr, MODINFO_SIZE); dynptr = preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_DYNAMIC); if (type == NULL || (strcmp(type, "elf" __XSTRING(__ELF_WORD_SIZE) " module") != 0 && strcmp(type, "elf module") != 0)) return (EFTYPE); if (baseptr == NULL || sizeptr == NULL || dynptr == NULL) return (EINVAL); lf = linker_make_file(filename, &link_elf_class); if (lf == NULL) return (ENOMEM); ef = (elf_file_t) lf; ef->preloaded = 1; ef->modptr = modptr; ef->address = *(caddr_t *)baseptr; #ifdef SPARSE_MAPPING ef->object = NULL; #endif dp = (vm_offset_t)ef->address + *(vm_offset_t *)dynptr; ef->dynamic = (Elf_Dyn *)dp; lf->address = ef->address; lf->size = *(size_t *)sizeptr; ctors_addrp = (Elf_Addr *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_CTORS_ADDR); ctors_sizep = (Elf_Size *)preload_search_info(modptr, MODINFO_METADATA | MODINFOMD_CTORS_SIZE); if (ctors_addrp != NULL && ctors_sizep != NULL) { lf->ctors_addr = ef->address + *ctors_addrp; lf->ctors_size = *ctors_sizep; } #ifdef __arm__ link_elf_locate_exidx_preload(lf, modptr); #endif error = parse_dynamic(ef); if (error == 0) error = parse_dpcpu(ef); #ifdef VIMAGE if (error == 0) error = parse_vnet(ef); #endif if (error == 0) error = preload_protect(ef, VM_PROT_ALL); if (error != 0) { linker_file_unload(lf, LINKER_UNLOAD_FORCE); return (error); } link_elf_reloc_local(lf); *result = lf; return (0); } static int link_elf_link_preload_finish(linker_file_t lf) { elf_file_t ef; int error; ef = (elf_file_t) lf; error = relocate_file(ef); if (error == 0) error = preload_protect(ef, VM_PROT_NONE); if (error != 0) return (error); (void)link_elf_preload_parse_symbols(ef); return (link_elf_link_common_finish(lf)); } static int link_elf_load_file(linker_class_t cls, const char* filename, linker_file_t* result) { struct nameidata nd; struct thread* td = curthread; /* XXX */ Elf_Ehdr *hdr; caddr_t firstpage, segbase; int nbytes, i; Elf_Phdr *phdr; Elf_Phdr *phlimit; Elf_Phdr *segs[MAXSEGS]; int nsegs; Elf_Phdr *phdyn; caddr_t mapbase; size_t mapsize; Elf_Addr base_vaddr; Elf_Addr base_vlimit; int error = 0; ssize_t resid; int flags; elf_file_t ef; linker_file_t lf; Elf_Shdr *shdr; int symtabindex; int symstrindex; int shstrindex; int symcnt; int strcnt; char *shstrs; shdr = NULL; lf = NULL; shstrs = NULL; NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, filename); flags = FREAD; error = vn_open(&nd, &flags, 0, NULL); if (error != 0) return (error); NDFREE_PNBUF(&nd); if (nd.ni_vp->v_type != VREG) { error = ENOEXEC; firstpage = NULL; goto out; } #ifdef MAC error = mac_kld_check_load(curthread->td_ucred, nd.ni_vp); if (error != 0) { firstpage = NULL; goto out; } #endif /* * Read the elf header from the file. */ firstpage = malloc(PAGE_SIZE, M_LINKER, M_WAITOK); hdr = (Elf_Ehdr *)firstpage; error = vn_rdwr(UIO_READ, nd.ni_vp, firstpage, PAGE_SIZE, 0, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); nbytes = PAGE_SIZE - resid; if (error != 0) goto out; if (!IS_ELF(*hdr)) { error = ENOEXEC; goto out; } if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || hdr->e_ident[EI_DATA] != ELF_TARG_DATA) { link_elf_error(filename, "Unsupported file layout"); error = ENOEXEC; goto out; } if (hdr->e_ident[EI_VERSION] != EV_CURRENT || hdr->e_version != EV_CURRENT) { link_elf_error(filename, "Unsupported file version"); error = ENOEXEC; goto out; } if (hdr->e_type != ET_EXEC && hdr->e_type != ET_DYN) { error = ENOSYS; goto out; } if (hdr->e_machine != ELF_TARG_MACH) { link_elf_error(filename, "Unsupported machine"); error = ENOEXEC; goto out; } /* * We rely on the program header being in the first page. * This is not strictly required by the ABI specification, but * it seems to always true in practice. And, it simplifies * things considerably. */ if (!((hdr->e_phentsize == sizeof(Elf_Phdr)) && (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= PAGE_SIZE) && (hdr->e_phoff + hdr->e_phnum*sizeof(Elf_Phdr) <= nbytes))) link_elf_error(filename, "Unreadable program headers"); /* * Scan the program header entries, and save key information. * * We rely on there being exactly two load segments, text and data, * in that order. */ phdr = (Elf_Phdr *) (firstpage + hdr->e_phoff); phlimit = phdr + hdr->e_phnum; nsegs = 0; phdyn = NULL; while (phdr < phlimit) { switch (phdr->p_type) { case PT_LOAD: if (nsegs == MAXSEGS) { link_elf_error(filename, "Too many sections"); error = ENOEXEC; goto out; } /* * XXX: We just trust they come in right order ?? */ segs[nsegs] = phdr; ++nsegs; break; case PT_DYNAMIC: phdyn = phdr; break; case PT_INTERP: error = ENOSYS; goto out; } ++phdr; } if (phdyn == NULL) { link_elf_error(filename, "Object is not dynamically-linked"); error = ENOEXEC; goto out; } if (nsegs == 0) { link_elf_error(filename, "No sections"); error = ENOEXEC; goto out; } /* * Allocate the entire address space of the object, to stake * out our contiguous region, and to establish the base * address for relocation. */ base_vaddr = trunc_page(segs[0]->p_vaddr); base_vlimit = round_page(segs[nsegs - 1]->p_vaddr + segs[nsegs - 1]->p_memsz); mapsize = base_vlimit - base_vaddr; lf = linker_make_file(filename, &link_elf_class); if (lf == NULL) { error = ENOMEM; goto out; } ef = (elf_file_t) lf; #ifdef SPARSE_MAPPING ef->object = vm_pager_allocate(OBJT_PHYS, NULL, mapsize, VM_PROT_ALL, 0, thread0.td_ucred); if (ef->object == NULL) { error = ENOMEM; goto out; } #ifdef __amd64__ mapbase = (caddr_t)KERNBASE; #else mapbase = (caddr_t)vm_map_min(kernel_map); #endif /* * Mapping protections are downgraded after relocation processing. */ error = vm_map_find(kernel_map, ef->object, 0, (vm_offset_t *)&mapbase, mapsize, 0, VMFS_OPTIMAL_SPACE, VM_PROT_ALL, VM_PROT_ALL, 0); if (error != 0) { vm_object_deallocate(ef->object); ef->object = NULL; goto out; } #else mapbase = malloc_exec(mapsize, M_LINKER, M_WAITOK); #endif ef->address = mapbase; /* * Read the text and data sections and zero the bss. */ for (i = 0; i < nsegs; i++) { segbase = mapbase + segs[i]->p_vaddr - base_vaddr; #ifdef SPARSE_MAPPING /* * Consecutive segments may have different mapping permissions, * so be strict and verify that their mappings do not overlap. */ if (((vm_offset_t)segbase & PAGE_MASK) != 0) { error = EINVAL; goto out; } error = vm_map_wire(kernel_map, (vm_offset_t)segbase, (vm_offset_t)segbase + round_page(segs[i]->p_memsz), VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); if (error != KERN_SUCCESS) { error = ENOMEM; goto out; } #endif error = vn_rdwr(UIO_READ, nd.ni_vp, segbase, segs[i]->p_filesz, segs[i]->p_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); if (error != 0) goto out; bzero(segbase + segs[i]->p_filesz, segs[i]->p_memsz - segs[i]->p_filesz); } ef->dynamic = (Elf_Dyn *) (mapbase + phdyn->p_vaddr - base_vaddr); lf->address = ef->address; lf->size = mapsize; error = parse_dynamic(ef); if (error != 0) goto out; error = parse_dpcpu(ef); if (error != 0) goto out; #ifdef VIMAGE error = parse_vnet(ef); if (error != 0) goto out; #endif link_elf_reloc_local(lf); VOP_UNLOCK(nd.ni_vp); error = linker_load_dependencies(lf); vn_lock(nd.ni_vp, LK_EXCLUSIVE | LK_RETRY); if (error != 0) goto out; error = relocate_file(ef); if (error != 0) goto out; #ifdef SPARSE_MAPPING /* * Downgrade permissions on text segment mappings now that relocation * processing is complete. Restrict permissions on read-only segments. */ for (i = 0; i < nsegs; i++) { vm_prot_t prot; if (segs[i]->p_type != PT_LOAD) continue; prot = VM_PROT_READ; if ((segs[i]->p_flags & PF_W) != 0) prot |= VM_PROT_WRITE; if ((segs[i]->p_flags & PF_X) != 0) prot |= VM_PROT_EXECUTE; segbase = mapbase + segs[i]->p_vaddr - base_vaddr; error = vm_map_protect(kernel_map, (vm_offset_t)segbase, (vm_offset_t)segbase + round_page(segs[i]->p_memsz), prot, 0, VM_MAP_PROTECT_SET_PROT); if (error != KERN_SUCCESS) { error = ENOMEM; goto out; } } #endif /* * Try and load the symbol table if it's present. (you can * strip it!) */ nbytes = hdr->e_shnum * hdr->e_shentsize; if (nbytes == 0 || hdr->e_shoff == 0) goto nosyms; shdr = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shdr, nbytes, hdr->e_shoff, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); if (error != 0) goto out; /* Read section string table */ shstrindex = hdr->e_shstrndx; if (shstrindex != 0 && shdr[shstrindex].sh_type == SHT_STRTAB && shdr[shstrindex].sh_size != 0) { nbytes = shdr[shstrindex].sh_size; shstrs = malloc(nbytes, M_LINKER, M_WAITOK | M_ZERO); error = vn_rdwr(UIO_READ, nd.ni_vp, (caddr_t)shstrs, nbytes, shdr[shstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); if (error) goto out; } symtabindex = -1; symstrindex = -1; for (i = 0; i < hdr->e_shnum; i++) { if (shdr[i].sh_type == SHT_SYMTAB) { symtabindex = i; symstrindex = shdr[i].sh_link; } else if (shstrs != NULL && shdr[i].sh_name != 0 && strcmp(shstrs + shdr[i].sh_name, ".ctors") == 0) { /* Record relocated address and size of .ctors. */ lf->ctors_addr = mapbase + shdr[i].sh_addr - base_vaddr; lf->ctors_size = shdr[i].sh_size; } } if (symtabindex < 0 || symstrindex < 0) goto nosyms; symcnt = shdr[symtabindex].sh_size; ef->symbase = malloc(symcnt, M_LINKER, M_WAITOK); strcnt = shdr[symstrindex].sh_size; ef->strbase = malloc(strcnt, M_LINKER, M_WAITOK); error = vn_rdwr(UIO_READ, nd.ni_vp, ef->symbase, symcnt, shdr[symtabindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); if (error != 0) goto out; error = vn_rdwr(UIO_READ, nd.ni_vp, ef->strbase, strcnt, shdr[symstrindex].sh_offset, UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred, NOCRED, &resid, td); if (error != 0) goto out; ef->ddbsymcnt = symcnt / sizeof(Elf_Sym); ef->ddbsymtab = (const Elf_Sym *)ef->symbase; ef->ddbstrcnt = strcnt; ef->ddbstrtab = ef->strbase; nosyms: #ifdef __arm__ link_elf_locate_exidx(lf, shdr, hdr->e_shnum); #endif error = link_elf_link_common_finish(lf); if (error != 0) goto out; *result = lf; out: VOP_UNLOCK(nd.ni_vp); vn_close(nd.ni_vp, FREAD, td->td_ucred, td); if (error != 0 && lf != NULL) linker_file_unload(lf, LINKER_UNLOAD_FORCE); free(shdr, M_LINKER); free(firstpage, M_LINKER); free(shstrs, M_LINKER); return (error); } Elf_Addr elf_relocaddr(linker_file_t lf, Elf_Addr x) { elf_file_t ef; KASSERT(lf->ops->cls == (kobj_class_t)&link_elf_class, ("elf_relocaddr: unexpected linker file %p", lf)); ef = (elf_file_t)lf; if (x >= ef->pcpu_start && x < ef->pcpu_stop) return ((x - ef->pcpu_start) + ef->pcpu_base); #ifdef VIMAGE if (x >= ef->vnet_start && x < ef->vnet_stop) return ((x - ef->vnet_start) + ef->vnet_base); #endif return (x); } static void link_elf_unload_file(linker_file_t file) { elf_file_t ef = (elf_file_t) file; if (ef->pcpu_base != 0) { dpcpu_free((void *)ef->pcpu_base, ef->pcpu_stop - ef->pcpu_start); elf_set_delete(&set_pcpu_list, ef->pcpu_start); } #ifdef VIMAGE if (ef->vnet_base != 0) { vnet_data_free((void *)ef->vnet_base, ef->vnet_stop - ef->vnet_start); elf_set_delete(&set_vnet_list, ef->vnet_start); } #endif #ifdef GDB if (ef->gdb.l_ld != NULL) { GDB_STATE(RT_DELETE); free((void *)(uintptr_t)ef->gdb.l_name, M_LINKER); link_elf_delete_gdb(&ef->gdb); GDB_STATE(RT_CONSISTENT); } #endif /* Notify MD code that a module is being unloaded. */ elf_cpu_unload_file(file); if (ef->preloaded) { link_elf_unload_preload(file); return; } #ifdef SPARSE_MAPPING if (ef->object != NULL) { vm_map_remove(kernel_map, (vm_offset_t) ef->address, (vm_offset_t) ef->address + (ef->object->size << PAGE_SHIFT)); } #else free(ef->address, M_LINKER); #endif free(ef->symbase, M_LINKER); free(ef->strbase, M_LINKER); free(ef->ctftab, M_LINKER); free(ef->ctfoff, M_LINKER); free(ef->typoff, M_LINKER); } static void link_elf_unload_preload(linker_file_t file) { if (file->pathname != NULL) preload_delete_name(file->pathname); } static const char * symbol_name(elf_file_t ef, Elf_Size r_info) { const Elf_Sym *ref; if (ELF_R_SYM(r_info)) { ref = ef->symtab + ELF_R_SYM(r_info); return (ef->strtab + ref->st_name); } return (NULL); } static int symbol_type(elf_file_t ef, Elf_Size r_info) { const Elf_Sym *ref; if (ELF_R_SYM(r_info)) { ref = ef->symtab + ELF_R_SYM(r_info); return (ELF_ST_TYPE(ref->st_info)); } return (STT_NOTYPE); } static int relocate_file1(elf_file_t ef, elf_lookup_fn lookup, elf_reloc_fn reloc, bool ifuncs) { const Elf_Rel *rel; const Elf_Rela *rela; const char *symname; #define APPLY_RELOCS(iter, tbl, tblsize, type) do { \ for ((iter) = (tbl); (iter) != NULL && \ (iter) < (tbl) + (tblsize) / sizeof(*(iter)); (iter)++) { \ if ((symbol_type(ef, (iter)->r_info) == \ STT_GNU_IFUNC || \ elf_is_ifunc_reloc((iter)->r_info)) != ifuncs) \ continue; \ if (reloc(&ef->lf, (Elf_Addr)ef->address, \ (iter), (type), lookup)) { \ symname = symbol_name(ef, (iter)->r_info); \ printf("link_elf: symbol %s undefined\n", \ symname); \ return (ENOENT); \ } \ } \ } while (0) APPLY_RELOCS(rel, ef->rel, ef->relsize, ELF_RELOC_REL); APPLY_RELOCS(rela, ef->rela, ef->relasize, ELF_RELOC_RELA); APPLY_RELOCS(rel, ef->pltrel, ef->pltrelsize, ELF_RELOC_REL); APPLY_RELOCS(rela, ef->pltrela, ef->pltrelasize, ELF_RELOC_RELA); #undef APPLY_RELOCS return (0); } static int relocate_file(elf_file_t ef) { int error; error = relocate_file1(ef, elf_lookup, elf_reloc, false); if (error == 0) error = relocate_file1(ef, elf_lookup, elf_reloc, true); return (error); } /* - * Hash function for symbol table lookup. Don't even think about changing - * this. It is specified by the System V ABI. + * SysV hash function for symbol table lookup. It is specified by the + * System V ABI. */ -static unsigned long +static Elf32_Word elf_hash(const char *name) { - const unsigned char *p = (const unsigned char *) name; - unsigned long h = 0; - unsigned long g; + const unsigned char *p = (const unsigned char *)name; + Elf32_Word h = 0; while (*p != '\0') { h = (h << 4) + *p++; - if ((g = h & 0xf0000000) != 0) - h ^= g >> 24; - h &= ~g; + h ^= (h >> 24) & 0xf0; } - return (h); + return (h & 0x0fffffff); } static int link_elf_lookup_symbol1(linker_file_t lf, const char *name, c_linker_sym_t *sym, bool see_local) { elf_file_t ef = (elf_file_t) lf; unsigned long symnum; const Elf_Sym* symp; const char *strp; - unsigned long hash; + Elf32_Word hash; /* If we don't have a hash, bail. */ if (ef->buckets == NULL || ef->nbuckets == 0) { printf("link_elf_lookup_symbol: missing symbol hash table\n"); return (ENOENT); } /* First, search hashed global symbols */ hash = elf_hash(name); symnum = ef->buckets[hash % ef->nbuckets]; while (symnum != STN_UNDEF) { if (symnum >= ef->nchains) { printf("%s: corrupt symbol table\n", __func__); return (ENOENT); } symp = ef->symtab + symnum; if (symp->st_name == 0) { printf("%s: corrupt symbol table\n", __func__); return (ENOENT); } strp = ef->strtab + symp->st_name; if (strcmp(name, strp) == 0) { if (symp->st_shndx != SHN_UNDEF || (symp->st_value != 0 && (ELF_ST_TYPE(symp->st_info) == STT_FUNC || ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { if (see_local || ELF_ST_BIND(symp->st_info) != STB_LOCAL) { *sym = (c_linker_sym_t) symp; return (0); } } return (ENOENT); } symnum = ef->chains[symnum]; } return (ENOENT); } static int link_elf_lookup_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) { if (link_elf_leak_locals) return (link_elf_lookup_debug_symbol(lf, name, sym)); return (link_elf_lookup_symbol1(lf, name, sym, false)); } static int link_elf_lookup_debug_symbol(linker_file_t lf, const char *name, c_linker_sym_t *sym) { elf_file_t ef = (elf_file_t)lf; const Elf_Sym* symp; const char *strp; int i; if (link_elf_lookup_symbol1(lf, name, sym, true) == 0) return (0); for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { strp = ef->ddbstrtab + symp->st_name; if (strcmp(name, strp) == 0) { if (symp->st_shndx != SHN_UNDEF || (symp->st_value != 0 && (ELF_ST_TYPE(symp->st_info) == STT_FUNC || ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC))) { *sym = (c_linker_sym_t) symp; return (0); } return (ENOENT); } } return (ENOENT); } static int link_elf_symbol_values1(linker_file_t lf, c_linker_sym_t sym, linker_symval_t *symval, bool see_local) { elf_file_t ef; const Elf_Sym *es; caddr_t val; ef = (elf_file_t)lf; es = (const Elf_Sym *)sym; if (es >= ef->symtab && es < ef->symtab + ef->nchains) { if (!see_local && ELF_ST_BIND(es->st_info) == STB_LOCAL) return (ENOENT); symval->name = ef->strtab + es->st_name; val = (caddr_t)ef->address + es->st_value; if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) val = ((caddr_t (*)(void))val)(); symval->value = val; symval->size = es->st_size; return (0); } return (ENOENT); } static int link_elf_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t *symval) { if (link_elf_leak_locals) return (link_elf_debug_symbol_values(lf, sym, symval)); return (link_elf_symbol_values1(lf, sym, symval, false)); } static int link_elf_debug_symbol_values(linker_file_t lf, c_linker_sym_t sym, linker_symval_t *symval) { elf_file_t ef = (elf_file_t)lf; const Elf_Sym *es = (const Elf_Sym *)sym; caddr_t val; if (link_elf_symbol_values1(lf, sym, symval, true) == 0) return (0); if (ef->symtab == ef->ddbsymtab) return (ENOENT); if (es >= ef->ddbsymtab && es < (ef->ddbsymtab + ef->ddbsymcnt)) { symval->name = ef->ddbstrtab + es->st_name; val = (caddr_t)ef->address + es->st_value; if (ELF_ST_TYPE(es->st_info) == STT_GNU_IFUNC) val = ((caddr_t (*)(void))val)(); symval->value = val; symval->size = es->st_size; return (0); } return (ENOENT); } static int link_elf_search_symbol(linker_file_t lf, caddr_t value, c_linker_sym_t *sym, long *diffp) { elf_file_t ef = (elf_file_t)lf; u_long off = (uintptr_t)(void *)value; u_long diff = off; u_long st_value; const Elf_Sym *es; const Elf_Sym *best = NULL; int i; for (i = 0, es = ef->ddbsymtab; i < ef->ddbsymcnt; i++, es++) { if (es->st_name == 0) continue; st_value = es->st_value + (uintptr_t) (void *) ef->address; if (off >= st_value) { if (off - st_value < diff) { diff = off - st_value; best = es; if (diff == 0) break; } else if (off - st_value == diff) { best = es; } } } if (best == NULL) *diffp = off; else *diffp = diff; *sym = (c_linker_sym_t) best; return (0); } /* * Look up a linker set on an ELF system. */ static int link_elf_lookup_set(linker_file_t lf, const char *name, void ***startp, void ***stopp, int *countp) { c_linker_sym_t sym; linker_symval_t symval; char *setsym; void **start, **stop; int len, error = 0, count; len = strlen(name) + sizeof("__start_set_"); /* sizeof includes \0 */ setsym = malloc(len, M_LINKER, M_WAITOK); /* get address of first entry */ snprintf(setsym, len, "%s%s", "__start_set_", name); error = link_elf_lookup_symbol(lf, setsym, &sym); if (error != 0) goto out; link_elf_symbol_values(lf, sym, &symval); if (symval.value == 0) { error = ESRCH; goto out; } start = (void **)symval.value; /* get address of last entry */ snprintf(setsym, len, "%s%s", "__stop_set_", name); error = link_elf_lookup_symbol(lf, setsym, &sym); if (error != 0) goto out; link_elf_symbol_values(lf, sym, &symval); if (symval.value == 0) { error = ESRCH; goto out; } stop = (void **)symval.value; /* and the number of entries */ count = stop - start; /* and copy out */ if (startp != NULL) *startp = start; if (stopp != NULL) *stopp = stop; if (countp != NULL) *countp = count; out: free(setsym, M_LINKER); return (error); } static int link_elf_each_function_name(linker_file_t file, int (*callback)(const char *, void *), void *opaque) { elf_file_t ef = (elf_file_t)file; const Elf_Sym *symp; int i, error; /* Exhaustive search */ for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { if (symp->st_value != 0 && (ELF_ST_TYPE(symp->st_info) == STT_FUNC || ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { error = callback(ef->ddbstrtab + symp->st_name, opaque); if (error != 0) return (error); } } return (0); } static int link_elf_each_function_nameval(linker_file_t file, linker_function_nameval_callback_t callback, void *opaque) { linker_symval_t symval; elf_file_t ef = (elf_file_t)file; const Elf_Sym *symp; int i, error; /* Exhaustive search */ for (i = 0, symp = ef->ddbsymtab; i < ef->ddbsymcnt; i++, symp++) { if (symp->st_value != 0 && (ELF_ST_TYPE(symp->st_info) == STT_FUNC || ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC)) { error = link_elf_debug_symbol_values(file, (c_linker_sym_t) symp, &symval); if (error == 0) error = callback(file, i, &symval, opaque); if (error != 0) return (error); } } return (0); } const Elf_Sym * elf_get_sym(linker_file_t lf, Elf_Size symidx) { elf_file_t ef = (elf_file_t)lf; if (symidx >= ef->nchains) return (NULL); return (ef->symtab + symidx); } const char * elf_get_symname(linker_file_t lf, Elf_Size symidx) { elf_file_t ef = (elf_file_t)lf; const Elf_Sym *sym; if (symidx >= ef->nchains) return (NULL); sym = ef->symtab + symidx; return (ef->strtab + sym->st_name); } /* * Symbol lookup function that can be used when the symbol index is known (ie * in relocations). It uses the symbol index instead of doing a fully fledged * hash table based lookup when such is valid. For example for local symbols. * This is not only more efficient, it's also more correct. It's not always * the case that the symbol can be found through the hash table. */ static int elf_lookup(linker_file_t lf, Elf_Size symidx, int deps, Elf_Addr *res) { elf_file_t ef = (elf_file_t)lf; const Elf_Sym *sym; const char *symbol; Elf_Addr addr, start, base; /* Don't even try to lookup the symbol if the index is bogus. */ if (symidx >= ef->nchains) { *res = 0; return (EINVAL); } sym = ef->symtab + symidx; /* * Don't do a full lookup when the symbol is local. It may even * fail because it may not be found through the hash table. */ if (ELF_ST_BIND(sym->st_info) == STB_LOCAL) { /* Force lookup failure when we have an insanity. */ if (sym->st_shndx == SHN_UNDEF || sym->st_value == 0) { *res = 0; return (EINVAL); } *res = ((Elf_Addr)ef->address + sym->st_value); return (0); } /* * XXX we can avoid doing a hash table based lookup for global * symbols as well. This however is not always valid, so we'll * just do it the hard way for now. Performance tweaks can * always be added. */ symbol = ef->strtab + sym->st_name; /* Force a lookup failure if the symbol name is bogus. */ if (*symbol == 0) { *res = 0; return (EINVAL); } addr = ((Elf_Addr)linker_file_lookup_symbol(lf, symbol, deps)); if (addr == 0 && ELF_ST_BIND(sym->st_info) != STB_WEAK) { *res = 0; return (EINVAL); } if (elf_set_find(&set_pcpu_list, addr, &start, &base)) addr = addr - start + base; #ifdef VIMAGE else if (elf_set_find(&set_vnet_list, addr, &start, &base)) addr = addr - start + base; #endif *res = addr; return (0); } static void link_elf_reloc_local(linker_file_t lf) { const Elf_Rel *rellim; const Elf_Rel *rel; const Elf_Rela *relalim; const Elf_Rela *rela; elf_file_t ef = (elf_file_t)lf; /* Perform relocations without addend if there are any: */ if ((rel = ef->rel) != NULL) { rellim = (const Elf_Rel *)((const char *)ef->rel + ef->relsize); while (rel < rellim) { elf_reloc_local(lf, (Elf_Addr)ef->address, rel, ELF_RELOC_REL, elf_lookup); rel++; } } /* Perform relocations with addend if there are any: */ if ((rela = ef->rela) != NULL) { relalim = (const Elf_Rela *) ((const char *)ef->rela + ef->relasize); while (rela < relalim) { elf_reloc_local(lf, (Elf_Addr)ef->address, rela, ELF_RELOC_RELA, elf_lookup); rela++; } } } static long link_elf_symtab_get(linker_file_t lf, const Elf_Sym **symtab) { elf_file_t ef = (elf_file_t)lf; *symtab = ef->ddbsymtab; if (*symtab == NULL) return (0); return (ef->ddbsymcnt); } static long link_elf_strtab_get(linker_file_t lf, caddr_t *strtab) { elf_file_t ef = (elf_file_t)lf; *strtab = ef->ddbstrtab; if (*strtab == NULL) return (0); return (ef->ddbstrcnt); } #if defined(__i386__) || defined(__amd64__) || defined(__aarch64__) || defined(__powerpc__) /* * Use this lookup routine when performing relocations early during boot. * The generic lookup routine depends on kobj, which is not initialized * at that point. */ static int elf_lookup_ifunc(linker_file_t lf, Elf_Size symidx, int deps __unused, Elf_Addr *res) { elf_file_t ef; const Elf_Sym *symp; caddr_t val; ef = (elf_file_t)lf; symp = ef->symtab + symidx; if (ELF_ST_TYPE(symp->st_info) == STT_GNU_IFUNC) { val = (caddr_t)ef->address + symp->st_value; *res = ((Elf_Addr (*)(void))val)(); return (0); } return (ENOENT); } void link_elf_ireloc(caddr_t kmdp) { struct elf_file eff; elf_file_t ef; ef = &eff; bzero_early(ef, sizeof(*ef)); ef->modptr = kmdp; ef->dynamic = (Elf_Dyn *)&_DYNAMIC; #ifdef RELOCATABLE_KERNEL ef->address = (caddr_t) (__startkernel - KERNBASE); #else ef->address = 0; #endif parse_dynamic(ef); link_elf_preload_parse_symbols(ef); relocate_file1(ef, elf_lookup_ifunc, elf_reloc, true); } #if defined(__aarch64__) || defined(__amd64__) void link_elf_late_ireloc(void) { elf_file_t ef; KASSERT(linker_kernel_file != NULL, ("link_elf_late_ireloc: No kernel linker file found")); ef = (elf_file_t)linker_kernel_file; relocate_file1(ef, elf_lookup_ifunc, elf_reloc_late, true); } #endif #endif