diff options
Diffstat (limited to 'sys/boot/common/load_elf_obj.c')
| -rw-r--r-- | sys/boot/common/load_elf_obj.c | 537 |
1 files changed, 537 insertions, 0 deletions
diff --git a/sys/boot/common/load_elf_obj.c b/sys/boot/common/load_elf_obj.c new file mode 100644 index 000000000000..a32b9fde4b75 --- /dev/null +++ b/sys/boot/common/load_elf_obj.c @@ -0,0 +1,537 @@ +/*- + * Copyright (c) 2004 Ian Dowse <iedowse@freebsd.org> + * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> + * Copyright (c) 1998 Peter Wemm <peter@freebsd.org> + * 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 <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> +#include <sys/exec.h> +#include <sys/linker.h> +#include <sys/module.h> +#include <inttypes.h> +#include <string.h> +#include <machine/elf.h> +#include <stand.h> +#define FREEBSD_ELF +#include <link.h> + +#include "bootstrap.h" + +#define COPYOUT(s,d,l) archsw.arch_copyout((vm_offset_t)(s), d, l) + +#if defined(__i386__) && __ELF_WORD_SIZE == 64 +#undef ELF_TARG_CLASS +#undef ELF_TARG_MACH +#define ELF_TARG_CLASS ELFCLASS64 +#define ELF_TARG_MACH EM_X86_64 +#endif + +typedef struct elf_file { + Elf_Ehdr hdr; + Elf_Shdr *e_shdr; + + int symtabindex; /* Index of symbol table */ + int shstrindex; /* Index of section name string table */ + + int fd; + vm_offset_t off; +} *elf_file_t; + +static int __elfN(obj_loadimage)(struct preloaded_file *mp, elf_file_t ef, + u_int64_t loadaddr); +static int __elfN(obj_lookup_set)(struct preloaded_file *mp, elf_file_t ef, + const char *name, Elf_Addr *startp, Elf_Addr *stopp, int *countp); +static int __elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, + Elf_Addr p, void *val, size_t len); +static int __elfN(obj_parse_modmetadata)(struct preloaded_file *mp, + elf_file_t ef); +static Elf_Addr __elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx); + +const char *__elfN(obj_kerneltype) = "elf kernel"; +const char *__elfN(obj_moduletype) = "elf obj module"; + +/* + * Attempt to load the file (file) as an ELF module. It will be stored at + * (dest), and a pointer to a module structure describing the loaded object + * will be saved in (result). + */ +int +__elfN(obj_loadfile)(char *filename, u_int64_t dest, + struct preloaded_file **result) +{ + struct preloaded_file *fp, *kfp; + struct elf_file ef; + Elf_Ehdr *hdr; + int err; + ssize_t bytes_read; + + fp = NULL; + bzero(&ef, sizeof(struct elf_file)); + + /* + * Open the image, read and validate the ELF header + */ + if (filename == NULL) /* can't handle nameless */ + return(EFTYPE); + if ((ef.fd = open(filename, O_RDONLY)) == -1) + return(errno); + + hdr = &ef.hdr; + bytes_read = read(ef.fd, hdr, sizeof(*hdr)); + if (bytes_read != sizeof(*hdr)) { + err = EFTYPE; /* could be EIO, but may be small file */ + goto oerr; + } + + /* Is it ELF? */ + if (!IS_ELF(*hdr)) { + err = EFTYPE; + goto oerr; + } + if (hdr->e_ident[EI_CLASS] != ELF_TARG_CLASS || /* Layout ? */ + hdr->e_ident[EI_DATA] != ELF_TARG_DATA || + hdr->e_ident[EI_VERSION] != EV_CURRENT || /* Version ? */ + hdr->e_version != EV_CURRENT || + hdr->e_machine != ELF_TARG_MACH || /* Machine ? */ + hdr->e_type != ET_REL) { + err = EFTYPE; + goto oerr; + } + + if (hdr->e_shnum * hdr->e_shentsize == 0 || hdr->e_shoff == 0 || + hdr->e_shentsize != sizeof(Elf_Shdr)) { + err = EFTYPE; + goto oerr; + } + + kfp = file_findfile(NULL, __elfN(obj_kerneltype)); + if (kfp == NULL) { + printf("elf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadfile: can't load module before kernel\n"); + err = EPERM; + goto oerr; + } + + if (archsw.arch_loadaddr != NULL) + dest = archsw.arch_loadaddr(LOAD_ELF, hdr, dest); + else + dest = roundup(dest, PAGE_SIZE); + + /* + * Ok, we think we should handle this. + */ + fp = file_alloc(); + if (fp == NULL) { + printf("elf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadfile: cannot allocate module info\n"); + err = EPERM; + goto out; + } + fp->f_name = strdup(filename); + fp->f_type = strdup(__elfN(obj_moduletype)); + + printf("%s ", filename); + + fp->f_size = __elfN(obj_loadimage)(fp, &ef, dest); + if (fp->f_size == 0 || fp->f_addr == 0) + goto ioerr; + + /* save exec header as metadata */ + file_addmetadata(fp, MODINFOMD_ELFHDR, sizeof(*hdr), hdr); + + /* Load OK, return module pointer */ + *result = (struct preloaded_file *)fp; + err = 0; + goto out; + +ioerr: + err = EIO; +oerr: + file_discard(fp); +out: + close(ef.fd); + if (ef.e_shdr != NULL) + free(ef.e_shdr); + + return(err); +} + +/* + * With the file (fd) open on the image, and (ehdr) containing + * the Elf header, load the image at (off) + */ +static int +__elfN(obj_loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off) +{ + Elf_Ehdr *hdr; + Elf_Shdr *shdr, *cshdr, *lshdr; + vm_offset_t firstaddr, lastaddr; + int i, nsym, res, ret, shdrbytes, symstrindex; + + ret = 0; + firstaddr = lastaddr = (vm_offset_t)off; + hdr = &ef->hdr; + ef->off = (vm_offset_t)off; + + /* Read in the section headers. */ + shdrbytes = hdr->e_shnum * hdr->e_shentsize; + shdr = alloc_pread(ef->fd, (off_t)hdr->e_shoff, shdrbytes); + if (shdr == NULL) { + printf("\nelf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadimage: read section headers failed\n"); + goto out; + } + ef->e_shdr = shdr; + + /* + * Decide where to load everything, but don't read it yet. + * We store the load address as a non-zero sh_addr value. + * Start with the code/data and bss. + */ + for (i = 0; i < hdr->e_shnum; i++) + shdr[i].sh_addr = 0; + for (i = 0; i < hdr->e_shnum; i++) { + if (shdr[i].sh_size == 0) + continue; + switch (shdr[i].sh_type) { + case SHT_PROGBITS: + case SHT_NOBITS: +#if defined(__i386__) || defined(__amd64__) + case SHT_X86_64_UNWIND: +#endif + lastaddr = roundup(lastaddr, shdr[i].sh_addralign); + shdr[i].sh_addr = (Elf_Addr)lastaddr; + lastaddr += shdr[i].sh_size; + break; + } + } + + /* Symbols. */ + nsym = 0; + for (i = 0; i < hdr->e_shnum; i++) { + switch (shdr[i].sh_type) { + case SHT_SYMTAB: + nsym++; + ef->symtabindex = i; + shdr[i].sh_addr = (Elf_Addr)lastaddr; + lastaddr += shdr[i].sh_size; + break; + } + } + if (nsym != 1) { + printf("\nelf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadimage: file has no valid symbol table\n"); + goto out; + } + lastaddr = roundup(lastaddr, shdr[ef->symtabindex].sh_addralign); + shdr[ef->symtabindex].sh_addr = (Elf_Addr)lastaddr; + lastaddr += shdr[ef->symtabindex].sh_size; + + symstrindex = shdr[ef->symtabindex].sh_link; + if (symstrindex < 0 || symstrindex >= hdr->e_shnum || + shdr[symstrindex].sh_type != SHT_STRTAB) { + printf("\nelf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadimage: file has invalid symbol strings\n"); + goto out; + } + lastaddr = roundup(lastaddr, shdr[symstrindex].sh_addralign); + shdr[symstrindex].sh_addr = (Elf_Addr)lastaddr; + lastaddr += shdr[symstrindex].sh_size; + + /* Section names. */ + if (hdr->e_shstrndx == 0 || hdr->e_shstrndx >= hdr->e_shnum || + shdr[hdr->e_shstrndx].sh_type != SHT_STRTAB) { + printf("\nelf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadimage: file has no section names\n"); + goto out; + } + ef->shstrindex = hdr->e_shstrndx; + lastaddr = roundup(lastaddr, shdr[ef->shstrindex].sh_addralign); + shdr[ef->shstrindex].sh_addr = (Elf_Addr)lastaddr; + lastaddr += shdr[ef->shstrindex].sh_size; + + /* Relocation tables. */ + for (i = 0; i < hdr->e_shnum; i++) { + switch (shdr[i].sh_type) { + case SHT_REL: + case SHT_RELA: + lastaddr = roundup(lastaddr, shdr[i].sh_addralign); + shdr[i].sh_addr = (Elf_Addr)lastaddr; + lastaddr += shdr[i].sh_size; + break; + } + } + + /* Clear the whole area, including bss regions. */ + kern_bzero(firstaddr, lastaddr - firstaddr); + + /* Figure section with the lowest file offset we haven't loaded yet. */ + for (cshdr = NULL; /* none */; /* none */) + { + /* + * Find next section to load. The complexity of this loop is + * O(n^2), but with the number of sections being typically + * small, we do not care. + */ + lshdr = cshdr; + + for (i = 0; i < hdr->e_shnum; i++) { + if (shdr[i].sh_addr == 0 || + shdr[i].sh_type == SHT_NOBITS) + continue; + /* Skip sections that were loaded already. */ + if (lshdr != NULL && + lshdr->sh_offset >= shdr[i].sh_offset) + continue; + /* Find section with smallest offset. */ + if (cshdr == lshdr || + cshdr->sh_offset > shdr[i].sh_offset) + cshdr = &shdr[i]; + } + + if (cshdr == lshdr) + break; + + if (kern_pread(ef->fd, (vm_offset_t)cshdr->sh_addr, + cshdr->sh_size, (off_t)cshdr->sh_offset) != 0) { + printf("\nelf" __XSTRING(__ELF_WORD_SIZE) + "_obj_loadimage: read failed\n"); + goto out; + } + } + + file_addmetadata(fp, MODINFOMD_SHDR, shdrbytes, shdr); + + res = __elfN(obj_parse_modmetadata)(fp, ef); + if (res != 0) + goto out; + + ret = lastaddr - firstaddr; + fp->f_addr = firstaddr; + + printf("size 0x%lx at 0x%lx", (u_long)ret, (u_long)firstaddr); + +out: + printf("\n"); + return ret; +} + +#if defined(__i386__) && __ELF_WORD_SIZE == 64 +struct mod_metadata64 { + int md_version; /* structure version MDTV_* */ + int md_type; /* type of entry MDT_* */ + u_int64_t md_data; /* specific data */ + u_int64_t md_cval; /* common string label */ +}; +#endif + +int +__elfN(obj_parse_modmetadata)(struct preloaded_file *fp, elf_file_t ef) +{ + struct mod_metadata md; +#if defined(__i386__) && __ELF_WORD_SIZE == 64 + struct mod_metadata64 md64; +#endif + struct mod_depend *mdepend; + struct mod_version mver; + char *s; + int error, modcnt, minfolen; + Elf_Addr v, p, p_stop; + + if (__elfN(obj_lookup_set)(fp, ef, "modmetadata_set", &p, &p_stop, + &modcnt) != 0) + return 0; + + modcnt = 0; + while (p < p_stop) { + COPYOUT(p, &v, sizeof(v)); + error = __elfN(obj_reloc_ptr)(fp, ef, p, &v, sizeof(v)); + if (error != 0) + return (error); +#if defined(__i386__) && __ELF_WORD_SIZE == 64 + COPYOUT(v, &md64, sizeof(md64)); + error = __elfN(obj_reloc_ptr)(fp, ef, v, &md64, sizeof(md64)); + if (error != 0) + return (error); + md.md_version = md64.md_version; + md.md_type = md64.md_type; + md.md_cval = (const char *)(uintptr_t)md64.md_cval; + md.md_data = (void *)(uintptr_t)md64.md_data; +#else + COPYOUT(v, &md, sizeof(md)); + error = __elfN(obj_reloc_ptr)(fp, ef, v, &md, sizeof(md)); + if (error != 0) + return (error); +#endif + p += sizeof(Elf_Addr); + switch(md.md_type) { + case MDT_DEPEND: + s = strdupout((vm_offset_t)md.md_cval); + minfolen = sizeof(*mdepend) + strlen(s) + 1; + mdepend = malloc(minfolen); + if (mdepend == NULL) + return ENOMEM; + COPYOUT((vm_offset_t)md.md_data, mdepend, + sizeof(*mdepend)); + strcpy((char*)(mdepend + 1), s); + free(s); + file_addmetadata(fp, MODINFOMD_DEPLIST, minfolen, + mdepend); + free(mdepend); + break; + case MDT_VERSION: + s = strdupout((vm_offset_t)md.md_cval); + COPYOUT((vm_offset_t)md.md_data, &mver, sizeof(mver)); + file_addmodule(fp, s, mver.mv_version, NULL); + free(s); + modcnt++; + break; + case MDT_MODULE: + case MDT_PNP_INFO: + break; + default: + printf("unknown type %d\n", md.md_type); + break; + } + } + return 0; +} + +static int +__elfN(obj_lookup_set)(struct preloaded_file *fp, elf_file_t ef, + const char* name, Elf_Addr *startp, Elf_Addr *stopp, int *countp) +{ + Elf_Ehdr *hdr; + Elf_Shdr *shdr; + char *p; + vm_offset_t shstrtab; + int i; + + hdr = &ef->hdr; + shdr = ef->e_shdr; + shstrtab = shdr[ef->shstrindex].sh_addr; + + for (i = 0; i < hdr->e_shnum; i++) { + if (shdr[i].sh_type != SHT_PROGBITS) + continue; + if (shdr[i].sh_name == 0) + continue; + p = strdupout(shstrtab + shdr[i].sh_name); + if (strncmp(p, "set_", 4) == 0 && strcmp(p + 4, name) == 0) { + *startp = shdr[i].sh_addr; + *stopp = shdr[i].sh_addr + shdr[i].sh_size; + *countp = (*stopp - *startp) / sizeof(Elf_Addr); + free(p); + return (0); + } + free(p); + } + + return (ESRCH); +} + +/* + * Apply any intra-module relocations to the value. p is the load address + * of the value and val/len is the value to be modified. This does NOT modify + * the image in-place, because this is done by kern_linker later on. + */ +static int +__elfN(obj_reloc_ptr)(struct preloaded_file *mp, elf_file_t ef, Elf_Addr p, + void *val, size_t len) +{ + Elf_Ehdr *hdr; + Elf_Shdr *shdr; + Elf_Addr off = p; + Elf_Addr base; + Elf_Rela a, *abase; + Elf_Rel r, *rbase; + int error, i, j, nrel, nrela; + + hdr = &ef->hdr; + shdr = ef->e_shdr; + + for (i = 0; i < hdr->e_shnum; i++) { + if (shdr[i].sh_type != SHT_RELA && shdr[i].sh_type != SHT_REL) + continue; + base = shdr[shdr[i].sh_info].sh_addr; + if (base == 0 || shdr[i].sh_addr == 0) + continue; + if (off < base || off + len > base + + shdr[shdr[i].sh_info].sh_size) + continue; + + switch (shdr[i].sh_type) { + case SHT_RELA: + abase = (Elf_Rela *)(intptr_t)shdr[i].sh_addr; + + nrela = shdr[i].sh_size / sizeof(Elf_Rela); + for (j = 0; j < nrela; j++) { + COPYOUT(abase + j, &a, sizeof(a)); + + error = __elfN(reloc)(ef, __elfN(obj_symaddr), + &a, ELF_RELOC_RELA, base, off, val, len); + if (error != 0) + return (error); + } + break; + case SHT_REL: + rbase = (Elf_Rel *)(intptr_t)shdr[i].sh_addr; + + nrel = shdr[i].sh_size / sizeof(Elf_Rel); + for (j = 0; j < nrel; j++) { + COPYOUT(rbase + j, &r, sizeof(r)); + + error = __elfN(reloc)(ef, __elfN(obj_symaddr), + &r, ELF_RELOC_REL, base, off, val, len); + if (error != 0) + return (error); + } + break; + } + } + return (0); +} + +/* Look up the address of a specified symbol. */ +static Elf_Addr +__elfN(obj_symaddr)(struct elf_file *ef, Elf_Size symidx) +{ + Elf_Sym sym; + Elf_Addr base; + + if (symidx >= ef->e_shdr[ef->symtabindex].sh_size / sizeof(Elf_Sym)) + return (0); + COPYOUT(ef->e_shdr[ef->symtabindex].sh_addr + symidx * sizeof(Elf_Sym), + &sym, sizeof(sym)); + if (sym.st_shndx == SHN_UNDEF || sym.st_shndx >= ef->hdr.e_shnum) + return (0); + base = ef->e_shdr[sym.st_shndx].sh_addr; + if (base == 0) + return (0); + return (base + sym.st_value); +} |