diff options
Diffstat (limited to 'lib/libc/gen/nlist.c')
| -rw-r--r-- | lib/libc/gen/nlist.c | 411 |
1 files changed, 411 insertions, 0 deletions
diff --git a/lib/libc/gen/nlist.c b/lib/libc/gen/nlist.c new file mode 100644 index 000000000000..159731c4337b --- /dev/null +++ b/lib/libc/gen/nlist.c @@ -0,0 +1,411 @@ +/* + * Copyright (c) 1989, 1993 + * The Regents of the University of California. 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. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. + */ + +#if defined(LIBC_SCCS) && !defined(lint) +static char sccsid[] = "@(#)nlist.c 8.1 (Berkeley) 6/4/93"; +#endif /* LIBC_SCCS and not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "namespace.h" +#include <sys/param.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/file.h> +#include <arpa/inet.h> + +#include <errno.h> +#include <a.out.h> +#include <stdio.h> +#include <string.h> +#include <unistd.h> +#include "un-namespace.h" + +#define _NLIST_DO_AOUT +#define _NLIST_DO_ELF + +#ifdef _NLIST_DO_ELF +#include <machine/elf.h> +#include <elf-hints.h> +#endif + +int __fdnlist(int, struct nlist *); +int __aout_fdnlist(int, struct nlist *); +int __elf_fdnlist(int, struct nlist *); + +int +nlist(name, list) + const char *name; + struct nlist *list; +{ + int fd, n; + + fd = _open(name, O_RDONLY | O_CLOEXEC, 0); + if (fd < 0) + return (-1); + n = __fdnlist(fd, list); + (void)_close(fd); + return (n); +} + +static struct nlist_handlers { + int (*fn)(int fd, struct nlist *list); +} nlist_fn[] = { +#ifdef _NLIST_DO_AOUT + { __aout_fdnlist }, +#endif +#ifdef _NLIST_DO_ELF + { __elf_fdnlist }, +#endif +}; + +int +__fdnlist(fd, list) + int fd; + struct nlist *list; +{ + int n = -1, i; + + for (i = 0; i < sizeof(nlist_fn) / sizeof(nlist_fn[0]); i++) { + n = (nlist_fn[i].fn)(fd, list); + if (n != -1) + break; + } + return (n); +} + +#define ISLAST(p) (p->n_un.n_name == 0 || p->n_un.n_name[0] == 0) + +#ifdef _NLIST_DO_AOUT +int +__aout_fdnlist(fd, list) + int fd; + struct nlist *list; +{ + struct nlist *p, *symtab; + caddr_t strtab, a_out_mmap; + off_t stroff, symoff; + u_long symsize; + int nent; + struct exec * exec; + struct stat st; + + /* check that file is at least as large as struct exec! */ + if ((_fstat(fd, &st) < 0) || (st.st_size < sizeof(struct exec))) + return (-1); + + /* Check for files too large to mmap. */ + if (st.st_size > SIZE_T_MAX) { + errno = EFBIG; + return (-1); + } + + /* + * Map the whole a.out file into our address space. + * We then find the string table withing this area. + * We do not just mmap the string table, as it probably + * does not start at a page boundary - we save ourselves a + * lot of nastiness by mmapping the whole file. + * + * This gives us an easy way to randomly access all the strings, + * without making the memory allocation permanent as with + * malloc/free (i.e., munmap will return it to the system). + */ + a_out_mmap = mmap(NULL, (size_t)st.st_size, PROT_READ, MAP_PRIVATE, fd, (off_t)0); + if (a_out_mmap == MAP_FAILED) + return (-1); + + exec = (struct exec *)a_out_mmap; + if (N_BADMAG(*exec)) { + munmap(a_out_mmap, (size_t)st.st_size); + return (-1); + } + + symoff = N_SYMOFF(*exec); + symsize = exec->a_syms; + stroff = symoff + symsize; + + /* find the string table in our mmapped area */ + strtab = a_out_mmap + stroff; + symtab = (struct nlist *)(a_out_mmap + symoff); + + /* + * clean out any left-over information for all valid entries. + * Type and value defined to be 0 if not found; historical + * versions cleared other and desc as well. Also figure out + * the largest string length so don't read any more of the + * string table than we have to. + * + * XXX clearing anything other than n_type and n_value violates + * the semantics given in the man page. + */ + nent = 0; + for (p = list; !ISLAST(p); ++p) { + p->n_type = 0; + p->n_other = 0; + p->n_desc = 0; + p->n_value = 0; + ++nent; + } + + while (symsize > 0) { + int soff; + + symsize-= sizeof(struct nlist); + soff = symtab->n_un.n_strx; + + + if (soff != 0 && (symtab->n_type & N_STAB) == 0) + for (p = list; !ISLAST(p); p++) + if (!strcmp(&strtab[soff], p->n_un.n_name)) { + p->n_value = symtab->n_value; + p->n_type = symtab->n_type; + p->n_desc = symtab->n_desc; + p->n_other = symtab->n_other; + if (--nent <= 0) + break; + } + symtab++; + } + munmap(a_out_mmap, (size_t)st.st_size); + return (nent); +} +#endif + +#ifdef _NLIST_DO_ELF +static void elf_sym_to_nlist(struct nlist *, Elf_Sym *, Elf_Shdr *, int); + +/* + * __elf_is_okay__ - Determine if ehdr really + * is ELF and valid for the target platform. + * + * WARNING: This is NOT an ELF ABI function and + * as such its use should be restricted. + */ +int +__elf_is_okay__(Elf_Ehdr *ehdr) +{ + int retval = 0; + /* + * We need to check magic, class size, endianess, + * and version before we look at the rest of the + * Elf_Ehdr structure. These few elements are + * represented in a machine independant fashion. + */ + if (IS_ELF(*ehdr) && + ehdr->e_ident[EI_CLASS] == ELF_TARG_CLASS && + ehdr->e_ident[EI_DATA] == ELF_TARG_DATA && + ehdr->e_ident[EI_VERSION] == ELF_TARG_VER) { + + /* Now check the machine dependant header */ + if (ehdr->e_machine == ELF_TARG_MACH && + ehdr->e_version == ELF_TARG_VER) + retval = 1; + } + return retval; +} + +int +__elf_fdnlist(fd, list) + int fd; + struct nlist *list; +{ + struct nlist *p; + Elf_Off symoff = 0, symstroff = 0; + Elf_Size symsize = 0, symstrsize = 0; + Elf_Ssize cc, i; + int nent = -1; + int errsave; + Elf_Sym sbuf[1024]; + Elf_Sym *s; + Elf_Ehdr ehdr; + char *strtab = NULL; + Elf_Shdr *shdr = NULL; + Elf_Size shdr_size; + void *base; + struct stat st; + + /* Make sure obj is OK */ + if (lseek(fd, (off_t)0, SEEK_SET) == -1 || + _read(fd, &ehdr, sizeof(Elf_Ehdr)) != sizeof(Elf_Ehdr) || + !__elf_is_okay__(&ehdr) || + _fstat(fd, &st) < 0) + return (-1); + + /* calculate section header table size */ + shdr_size = ehdr.e_shentsize * ehdr.e_shnum; + + /* Make sure it's not too big to mmap */ + if (shdr_size > SIZE_T_MAX) { + errno = EFBIG; + return (-1); + } + + /* mmap section header table */ + base = mmap(NULL, (size_t)shdr_size, PROT_READ, 0, fd, + (off_t)ehdr.e_shoff); + if (base == MAP_FAILED) + return (-1); + shdr = (Elf_Shdr *)base; + + /* + * Find the symbol table entry and it's corresponding + * string table entry. Version 1.1 of the ABI states + * that there is only one symbol table but that this + * could change in the future. + */ + for (i = 0; i < ehdr.e_shnum; i++) { + if (shdr[i].sh_type == SHT_SYMTAB) { + symoff = shdr[i].sh_offset; + symsize = shdr[i].sh_size; + symstroff = shdr[shdr[i].sh_link].sh_offset; + symstrsize = shdr[shdr[i].sh_link].sh_size; + break; + } + } + + /* Check for files too large to mmap. */ + if (symstrsize > SIZE_T_MAX) { + errno = EFBIG; + goto done; + } + /* + * Map string table into our address space. This gives us + * an easy way to randomly access all the strings, without + * making the memory allocation permanent as with malloc/free + * (i.e., munmap will return it to the system). + */ + base = mmap(NULL, (size_t)symstrsize, PROT_READ, 0, fd, + (off_t)symstroff); + if (base == MAP_FAILED) + goto done; + strtab = (char *)base; + + /* + * clean out any left-over information for all valid entries. + * Type and value defined to be 0 if not found; historical + * versions cleared other and desc as well. Also figure out + * the largest string length so don't read any more of the + * string table than we have to. + * + * XXX clearing anything other than n_type and n_value violates + * the semantics given in the man page. + */ + nent = 0; + for (p = list; !ISLAST(p); ++p) { + p->n_type = 0; + p->n_other = 0; + p->n_desc = 0; + p->n_value = 0; + ++nent; + } + + /* Don't process any further if object is stripped. */ + if (symoff == 0) + goto done; + + if (lseek(fd, (off_t) symoff, SEEK_SET) == -1) { + nent = -1; + goto done; + } + + while (symsize > 0 && nent > 0) { + cc = MIN(symsize, sizeof(sbuf)); + if (_read(fd, sbuf, cc) != cc) + break; + symsize -= cc; + for (s = sbuf; cc > 0 && nent > 0; ++s, cc -= sizeof(*s)) { + char *name; + struct nlist *p; + + name = strtab + s->st_name; + if (name[0] == '\0') + continue; + for (p = list; !ISLAST(p); p++) { + if ((p->n_un.n_name[0] == '_' && + strcmp(name, p->n_un.n_name+1) == 0) + || strcmp(name, p->n_un.n_name) == 0) { + elf_sym_to_nlist(p, s, shdr, + ehdr.e_shnum); + if (--nent <= 0) + break; + } + } + } + } + done: + errsave = errno; + if (strtab != NULL) + munmap(strtab, symstrsize); + if (shdr != NULL) + munmap(shdr, shdr_size); + errno = errsave; + return (nent); +} + +/* + * Convert an Elf_Sym into an nlist structure. This fills in only the + * n_value and n_type members. + */ +static void +elf_sym_to_nlist(nl, s, shdr, shnum) + struct nlist *nl; + Elf_Sym *s; + Elf_Shdr *shdr; + int shnum; +{ + nl->n_value = s->st_value; + + switch (s->st_shndx) { + case SHN_UNDEF: + case SHN_COMMON: + nl->n_type = N_UNDF; + break; + case SHN_ABS: + nl->n_type = ELF_ST_TYPE(s->st_info) == STT_FILE ? + N_FN : N_ABS; + break; + default: + if (s->st_shndx >= shnum) + nl->n_type = N_UNDF; + else { + Elf_Shdr *sh = shdr + s->st_shndx; + + nl->n_type = sh->sh_type == SHT_PROGBITS ? + (sh->sh_flags & SHF_WRITE ? N_DATA : N_TEXT) : + (sh->sh_type == SHT_NOBITS ? N_BSS : N_UNDF); + } + break; + } + + if (ELF_ST_BIND(s->st_info) == STB_GLOBAL || + ELF_ST_BIND(s->st_info) == STB_WEAK) + nl->n_type |= N_EXT; +} +#endif /* _NLIST_DO_ELF */ |