From 8e62a71738bcbefdbb76435d94be5d455b9ee192 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 27 Jul 2010 10:25:37 -0700 Subject: linux-user: Extract load_elf_image from load_elf_interp. Moving toward a single copy of the elf binary loading code. Fill in the details of the loaded image into a struct image_info. Adjust create_elf_tables to read from such structures instead of from a collection of passed arguments. Don't return error values from load_elf_interp; always exit(-1) with a message to stderr. Collect elf_interpreter handling in load_elf_binary to a common spot. Signed-off-by: Richard Henderson Signed-off-by: Edgar E. Iglesias --- linux-user/elfload.c | 341 +++++++++++++++++++++++++-------------------------- 1 file changed, 167 insertions(+), 174 deletions(-) (limited to 'linux-user/elfload.c') diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 61167cdcb..0a3d0844b 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1079,11 +1079,9 @@ static void zero_bss(abi_ulong elf_bss, abi_ulong last_bss, int prot) } static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, - struct elfhdr * exec, - abi_ulong load_addr, - abi_ulong load_bias, - abi_ulong interp_load_addr, - struct image_info *info) + struct elfhdr *exec, + struct image_info *info, + struct image_info *interp_info) { abi_ulong sp; int size; @@ -1128,13 +1126,13 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, NEW_AUX_ENT (AT_NULL, 0); /* There must be exactly DLINFO_ITEMS entries here. */ - NEW_AUX_ENT(AT_PHDR, (abi_ulong)(load_addr + exec->e_phoff)); + NEW_AUX_ENT(AT_PHDR, (abi_ulong)(info->load_addr + exec->e_phoff)); NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof (struct elf_phdr))); NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum)); NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(TARGET_PAGE_SIZE)); - NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_load_addr)); + NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_info ? interp_info->load_addr : 0)); NEW_AUX_ENT(AT_FLAGS, (abi_ulong)0); - NEW_AUX_ENT(AT_ENTRY, load_bias + exec->e_entry); + NEW_AUX_ENT(AT_ENTRY, info->entry); NEW_AUX_ENT(AT_UID, (abi_ulong) getuid()); NEW_AUX_ENT(AT_EUID, (abi_ulong) geteuid()); NEW_AUX_ENT(AT_GID, (abi_ulong) getgid()); @@ -1158,51 +1156,60 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, return sp; } +/* Load an ELF image into the address space. -static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, - int interpreter_fd, - abi_ulong *interp_load_addr, - char bprm_buf[BPRM_BUF_SIZE]) + IMAGE_NAME is the filename of the image, to use in error messages. + IMAGE_FD is the open file descriptor for the image. + + BPRM_BUF is a copy of the beginning of the file; this of course + contains the elf file header at offset 0. It is assumed that this + buffer is sufficiently aligned to present no problems to the host + in accessing data at aligned offsets within the buffer. + + On return: INFO values will be filled in, as necessary or available. */ + +static void load_elf_image(const char *image_name, int image_fd, + struct image_info *info, + char bprm_buf[BPRM_BUF_SIZE]) { - struct elf_phdr *elf_phdata = NULL; - abi_ulong load_addr, load_bias, loaddr, hiaddr; - int retval; - abi_ulong error; - int i; + struct elfhdr *ehdr = (struct elfhdr *)bprm_buf; + struct elf_phdr *phdr; + abi_ulong load_addr, load_bias, loaddr, hiaddr, error; + int i, retval; + const char *errmsg; - bswap_ehdr(interp_elf_ex); - if (!elf_check_ehdr(interp_elf_ex)) { - return ~((abi_ulong)0UL); + /* First of all, some simple consistency checks */ + errmsg = "Invalid ELF image for this architecture"; + if (!elf_check_ident(ehdr)) { + goto exit_errmsg; + } + bswap_ehdr(ehdr); + if (!elf_check_ehdr(ehdr)) { + goto exit_errmsg; } - /* Now read in all of the header information */ - elf_phdata = (struct elf_phdr *) - malloc(sizeof(struct elf_phdr) * interp_elf_ex->e_phnum); - if (!elf_phdata) - return ~((abi_ulong)0UL); - - i = interp_elf_ex->e_phnum * sizeof(struct elf_phdr); - if (interp_elf_ex->e_phoff + i <= BPRM_BUF_SIZE) { - memcpy(elf_phdata, bprm_buf + interp_elf_ex->e_phoff, i); + i = ehdr->e_phnum * sizeof(struct elf_phdr); + if (ehdr->e_phoff + i <= BPRM_BUF_SIZE) { + phdr = (struct elf_phdr *)(bprm_buf + ehdr->e_phoff); } else { - retval = pread(interpreter_fd, elf_phdata, i, interp_elf_ex->e_phoff); + phdr = (struct elf_phdr *) alloca(i); + retval = pread(image_fd, phdr, i, ehdr->e_phoff); if (retval != i) { - perror("load_elf_interp"); - exit(-1); + goto exit_read; } } - bswap_phdr(elf_phdata, interp_elf_ex->e_phnum); + bswap_phdr(phdr, ehdr->e_phnum); /* Find the maximum size of the image and allocate an appropriate amount of memory to handle that. */ loaddr = -1, hiaddr = 0; - for (i = 0; i < interp_elf_ex->e_phnum; ++i) { - if (elf_phdata[i].p_type == PT_LOAD) { - abi_ulong a = elf_phdata[i].p_vaddr; + for (i = 0; i < ehdr->e_phnum; ++i) { + if (phdr[i].p_type == PT_LOAD) { + abi_ulong a = phdr[i].p_vaddr; if (a < loaddr) { loaddr = a; } - a += elf_phdata[i].p_memsz; + a += phdr[i].p_memsz; if (a > hiaddr) { hiaddr = a; } @@ -1210,7 +1217,7 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, } load_addr = loaddr; - if (interp_elf_ex->e_type == ET_DYN) { + if (ehdr->e_type == ET_DYN) { /* The image indicates that it can be loaded anywhere. Find a location that can hold the memory space required. If the image is pre-linked, LOADDR will be non-zero. Since we do @@ -1220,14 +1227,22 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, MAP_PRIVATE | MAP_ANON | MAP_NORESERVE, -1, 0); if (load_addr == -1) { - perror("mmap"); - exit(-1); + goto exit_perror; } } load_bias = load_addr - loaddr; - for (i = 0; i < interp_elf_ex->e_phnum; i++) { - struct elf_phdr *eppnt = elf_phdata + i; + info->load_bias = load_bias; + info->load_addr = load_addr; + info->entry = ehdr->e_entry + load_bias; + info->start_code = -1; + info->end_code = 0; + info->start_data = -1; + info->end_data = 0; + info->brk = 0; + + for (i = 0; i < ehdr->e_phnum; i++) { + struct elf_phdr *eppnt = phdr + i; if (eppnt->p_type == PT_LOAD) { abi_ulong vaddr, vaddr_po, vaddr_ps, vaddr_ef, vaddr_em; int elf_prot = 0; @@ -1242,12 +1257,9 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, error = target_mmap(vaddr_ps, eppnt->p_filesz + vaddr_po, elf_prot, MAP_PRIVATE | MAP_FIXED, - interpreter_fd, eppnt->p_offset - vaddr_po); + image_fd, eppnt->p_offset - vaddr_po); if (error == -1) { - /* Real error */ - close(interpreter_fd); - free(elf_phdata); - return ~((abi_ulong)0UL); + goto exit_perror; } vaddr_ef = vaddr + eppnt->p_filesz; @@ -1257,18 +1269,79 @@ static abi_ulong load_elf_interp(struct elfhdr * interp_elf_ex, if (vaddr_ef < vaddr_em) { zero_bss(vaddr_ef, vaddr_em, elf_prot); } + + /* Find the full program boundaries. */ + if (elf_prot & PROT_EXEC) { + if (vaddr < info->start_code) { + info->start_code = vaddr; + } + if (vaddr_ef > info->end_code) { + info->end_code = vaddr_ef; + } + } + if (elf_prot & PROT_WRITE) { + if (vaddr < info->start_data) { + info->start_data = vaddr; + } + if (vaddr_ef > info->end_data) { + info->end_data = vaddr_ef; + } + if (vaddr_em > info->brk) { + info->brk = vaddr_em; + } + } } } + if (info->end_data == 0) { + info->start_data = info->end_code; + info->end_data = info->end_code; + info->brk = info->end_code; + } + if (qemu_log_enabled()) { - load_symbols(interp_elf_ex, interpreter_fd, load_bias); + load_symbols(ehdr, image_fd, load_bias); } - close(interpreter_fd); - free(elf_phdata); + close(image_fd); + return; + + exit_read: + if (retval >= 0) { + errmsg = "Incomplete read of file header"; + goto exit_errmsg; + } + exit_perror: + errmsg = strerror(errno); + exit_errmsg: + fprintf(stderr, "%s: %s\n", image_name, errmsg); + exit(-1); +} + +static void load_elf_interp(const char *filename, struct image_info *info, + char bprm_buf[BPRM_BUF_SIZE]) +{ + int fd, retval; + + fd = open(path(filename), O_RDONLY); + if (fd < 0) { + goto exit_perror; + } + + retval = read(fd, bprm_buf, BPRM_BUF_SIZE); + if (retval < 0) { + goto exit_perror; + } + if (retval < BPRM_BUF_SIZE) { + memset(bprm_buf + retval, 0, BPRM_BUF_SIZE - retval); + } + + load_elf_image(filename, fd, info, bprm_buf); + return; - *interp_load_addr = load_addr; - return ((abi_ulong) interp_elf_ex->e_entry) + load_bias; + exit_perror: + fprintf(stderr, "%s: %s\n", filename, strerror(errno)); + exit(-1); } static int symfind(const void *s0, const void *s1) @@ -1405,26 +1478,21 @@ static void load_symbols(struct elfhdr *hdr, int fd, abi_ulong load_bias) int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, struct image_info * info) { + struct image_info interp_info; struct elfhdr elf_ex; - struct elfhdr interp_elf_ex; - int interpreter_fd = -1; /* avoid warning */ abi_ulong load_addr, load_bias; int load_addr_set = 0; - unsigned char ibcs2_interpreter; int i; - abi_ulong mapped_addr; struct elf_phdr * elf_ppnt; struct elf_phdr *elf_phdata; abi_ulong k, elf_brk; int retval; - char * elf_interpreter; - abi_ulong elf_entry, interp_load_addr = 0; + char *elf_interpreter = NULL; + abi_ulong elf_entry; int status; abi_ulong start_code, end_code, start_data, end_data; - abi_ulong reloc_func_desc = 0; abi_ulong elf_stack; - ibcs2_interpreter = 0; status = 0; load_addr = 0; load_bias = 0; @@ -1467,7 +1535,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, elf_brk = 0; elf_stack = ~((abi_ulong)0UL); - elf_interpreter = NULL; start_code = ~((abi_ulong)0UL); end_code = 0; start_data = 0; @@ -1476,82 +1543,21 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, elf_ppnt = elf_phdata; for(i=0;i < elf_ex.e_phnum; i++) { if (elf_ppnt->p_type == PT_INTERP) { - if ( elf_interpreter != NULL ) - { - free (elf_phdata); - free(elf_interpreter); - close(bprm->fd); - return -EINVAL; - } - - /* This is the program interpreter used for - * shared libraries - for now assume that this - * is an a.out format binary - */ - - elf_interpreter = (char *)malloc(elf_ppnt->p_filesz); - - if (elf_interpreter == NULL) { - free (elf_phdata); - close(bprm->fd); - return -ENOMEM; - } - if (elf_ppnt->p_offset + elf_ppnt->p_filesz <= BPRM_BUF_SIZE) { - memcpy(elf_interpreter, bprm->buf + elf_ppnt->p_offset, - elf_ppnt->p_filesz); + elf_interpreter = bprm->buf + elf_ppnt->p_offset; } else { + elf_interpreter = alloca(elf_ppnt->p_filesz); retval = pread(bprm->fd, elf_interpreter, elf_ppnt->p_filesz, elf_ppnt->p_offset); if (retval != elf_ppnt->p_filesz) { - perror("load_elf_binary2"); + perror("load_elf_binary"); exit(-1); } } - - /* If the program interpreter is one of these two, - then assume an iBCS2 image. Otherwise assume - a native linux image. */ - - /* JRP - Need to add X86 lib dir stuff here... */ - - if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 || - strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0) { - ibcs2_interpreter = 1; - } - - retval = open(path(elf_interpreter), O_RDONLY); - if (retval < 0) { - perror(elf_interpreter); - exit(-1); - } - interpreter_fd = retval; - - retval = read(interpreter_fd, bprm->buf, BPRM_BUF_SIZE); - if (retval < 0) { - perror("load_elf_binary3"); - exit(-1); - } - if (retval < BPRM_BUF_SIZE) { - memset(bprm->buf, 0, BPRM_BUF_SIZE - retval); - } - - interp_elf_ex = *((struct elfhdr *) bprm->buf); } elf_ppnt++; } - /* Some simple consistency checks for the interpreter */ - if (elf_interpreter) { - if (!elf_check_ident(&interp_elf_ex)) { - free(elf_interpreter); - free(elf_phdata); - close(bprm->fd); - close(interpreter_fd); - return -ELIBBAD; - } - } - /* OK, This is the point of no return */ info->end_data = 0; info->end_code = 0; @@ -1710,7 +1716,6 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, load_bias += error - TARGET_ELF_PAGESTART(load_bias + elf_ppnt->p_vaddr); load_addr += load_bias; - reloc_func_desc = load_bias; } } k = elf_ppnt->p_vaddr; @@ -1743,19 +1748,15 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, start_data += load_bias; end_data += load_bias; - if (elf_interpreter) { - elf_entry = load_elf_interp(&interp_elf_ex, interpreter_fd, - &interp_load_addr, bprm->buf); - reloc_func_desc = interp_load_addr; - free(elf_interpreter); - - if (elf_entry == ~((abi_ulong)0UL)) { - printf("Unable to load interpreter\n"); - free(elf_phdata); - exit(-1); - return 0; - } - } + info->load_bias = load_bias; + info->load_addr = load_addr; + info->entry = elf_entry; + info->start_brk = info->brk = elf_brk; + info->end_code = end_code; + info->start_code = start_code; + info->start_data = start_data; + info->end_data = end_data; + info->personality = PER_LINUX; free(elf_phdata); @@ -1764,46 +1765,38 @@ int load_elf_binary(struct linux_binprm * bprm, struct target_pt_regs * regs, } close(bprm->fd); - info->personality = (ibcs2_interpreter ? PER_SVR4 : PER_LINUX); -#ifdef LOW_ELF_STACK - info->start_stack = bprm->p = elf_stack - 4; -#endif - bprm->p = create_elf_tables(bprm->p, - bprm->argc, - bprm->envc, - &elf_ex, - load_addr, load_bias, - interp_load_addr, - info); - info->load_addr = reloc_func_desc; - info->start_brk = info->brk = elf_brk; - info->end_code = end_code; - info->start_code = start_code; - info->start_data = start_data; - info->end_data = end_data; - info->start_stack = bprm->p; + if (elf_interpreter) { + load_elf_interp(elf_interpreter, &interp_info, bprm->buf); -#if 0 - printf("(start_brk) %x\n" , info->start_brk); - printf("(end_code) %x\n" , info->end_code); - printf("(start_code) %x\n" , info->start_code); - printf("(end_data) %x\n" , info->end_data); - printf("(start_stack) %x\n" , info->start_stack); - printf("(brk) %x\n" , info->brk); -#endif + /* If the program interpreter is one of these two, then assume + an iBCS2 image. Otherwise assume a native linux image. */ + + if (strcmp(elf_interpreter, "/usr/lib/libc.so.1") == 0 + || strcmp(elf_interpreter, "/usr/lib/ld.so.1") == 0) { + info->personality = PER_SVR4; - if ( info->personality == PER_SVR4 ) - { - /* Why this, you ask??? Well SVr4 maps page 0 as read-only, - and some applications "depend" upon this behavior. - Since we do not have the power to recompile these, we - emulate the SVr4 behavior. Sigh. */ - mapped_addr = target_mmap(0, qemu_host_page_size, PROT_READ | PROT_EXEC, - MAP_FIXED | MAP_PRIVATE, -1, 0); + /* Why this, you ask??? Well SVr4 maps page 0 as read-only, + and some applications "depend" upon this behavior. Since + we do not have the power to recompile these, we emulate + the SVr4 behavior. Sigh. */ + target_mmap(0, qemu_host_page_size, PROT_READ | PROT_EXEC, + MAP_FIXED | MAP_PRIVATE, -1, 0); + } } - info->entry = elf_entry; + bprm->p = create_elf_tables(bprm->p, bprm->argc, bprm->envc, &elf_ex, + info, (elf_interpreter ? &interp_info : NULL)); + info->start_stack = bprm->p; + + /* If we have an interpreter, set that as the program's entry point. + Copy the load_addr as well, to help PPC64 interpret the entry + point as a function descriptor. Do this after creating elf tables + so that we copy the original program entry point into the AUXV. */ + if (elf_interpreter) { + info->load_addr = interp_info.load_addr; + info->entry = interp_info.entry; + } #ifdef USE_ELF_CORE_DUMP bprm->core_dump = &elf_core_dump; -- cgit v1.2.3