diff options
Diffstat (limited to 'linkers/elftoolchain/libelf/elf_begin.c')
| -rw-r--r-- | linkers/elftoolchain/libelf/elf_begin.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/linkers/elftoolchain/libelf/elf_begin.c b/linkers/elftoolchain/libelf/elf_begin.c new file mode 100644 index 0000000..a6c9e4a --- /dev/null +++ b/linkers/elftoolchain/libelf/elf_begin.c @@ -0,0 +1,276 @@ +/*- + * Copyright (c) 2006,2008-2011 Joseph Koshy + * 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> + +#include <sys/types.h> +#include <sys/errno.h> +#include <sys/mman.h> +#include <sys/stat.h> + +#include <ar.h> +#include <assert.h> +#include <ctype.h> +#include <errno.h> +#include <libelf.h> +#include <stdlib.h> +#include <unistd.h> + +#include "_libelf.h" + +LIBELF_VCSID("$Id: elf_begin.c 1923 2011-09-23 09:01:13Z jkoshy $"); + +#define _LIBELF_INITSIZE (64*1024) + +/* + * Read from a device file, pipe or socket. + */ +static void * +_libelf_read_special_file(int fd, size_t *fsz) +{ + ssize_t readsz; + size_t bufsz, datasz; + unsigned char *buf, *t; + + datasz = 0; + readsz = 0; + bufsz = _LIBELF_INITSIZE; + if ((buf = malloc(bufsz)) == NULL) + goto resourceerror; + + /* + * Read data from the file descriptor till we reach EOF, or + * till an error is encountered. + */ + do { + /* Check if we need to expand the data buffer. */ + if (datasz == bufsz) { + bufsz *= 2; + if ((t = realloc(buf, bufsz)) == NULL) + goto resourceerror; + buf = t; + } + + do { + readsz = bufsz - datasz; + t = buf + datasz; + if ((readsz = read(fd, t, readsz)) <= 0) + break; + datasz += readsz; + } while (datasz < bufsz); + + } while (readsz > 0); + + if (readsz < 0) { + LIBELF_SET_ERROR(IO, errno); + goto error; + } + + assert(readsz == 0); + + /* + * Free up extra buffer space. + */ + if (bufsz > datasz) { + if (datasz > 0) { + if ((t = realloc(buf, datasz)) == NULL) + goto resourceerror; + buf = t; + } else { /* Zero bytes read. */ + LIBELF_SET_ERROR(ARGUMENT, 0); + free(buf); + buf = NULL; + } + } + + *fsz = datasz; + return (buf); + +resourceerror: + LIBELF_SET_ERROR(RESOURCE, 0); +error: + if (buf != NULL) + free(buf); + return (NULL); +} + + +static Elf * +_libelf_open_object(int fd, Elf_Cmd c) +{ + Elf *e; + void *m; + mode_t mode; + size_t fsize; + struct stat sb; + unsigned int flags; + + assert(c == ELF_C_READ || c == ELF_C_RDWR || c == ELF_C_WRITE); + + if (fstat(fd, &sb) < 0) { + LIBELF_SET_ERROR(IO, errno); + return (NULL); + } + + mode = sb.st_mode; + fsize = (size_t) sb.st_size; + + /* + * Reject unsupported file types. + */ + if (!S_ISREG(mode) && !S_ISCHR(mode) && !S_ISFIFO(mode) && + !S_ISSOCK(mode)) { + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + + /* + * For ELF_C_WRITE mode, allocate and return a descriptor. + */ + if (c == ELF_C_WRITE) { + if ((e = _libelf_allocate_elf()) != NULL) { + _libelf_init_elf(e, ELF_K_ELF); + e->e_byteorder = LIBELF_PRIVATE(byteorder); + e->e_fd = fd; + e->e_cmd = c; + if (!S_ISREG(mode)) + e->e_flags |= LIBELF_F_SPECIAL_FILE; + } + + return (e); + } + + + /* + * ELF_C_READ and ELF_C_RDWR mode. + */ + m = NULL; + flags = 0; + if (S_ISREG(mode)) { + /* + * Always map regular files in with 'PROT_READ' + * permissions. + * + * For objects opened in ELF_C_RDWR mode, when + * elf_update(3) is called, we remove this mapping, + * write file data out using write(2), and map the new + * contents back. + */ + if ((m = mmap(NULL, fsize, PROT_READ, MAP_PRIVATE, fd, + (off_t) 0)) == MAP_FAILED) { + LIBELF_SET_ERROR(IO, errno); + return (NULL); + } + + flags = LIBELF_F_RAWFILE_MMAP; + } else if ((m = _libelf_read_special_file(fd, &fsize)) != NULL) + flags = LIBELF_F_RAWFILE_MALLOC | LIBELF_F_SPECIAL_FILE; + else + return (NULL); + + if ((e = elf_memory(m, fsize)) == NULL) { + assert((flags & LIBELF_F_RAWFILE_MALLOC) || + (flags & LIBELF_F_RAWFILE_MMAP)); + if (flags & LIBELF_F_RAWFILE_MMAP) + (void) munmap(m, fsize); + else + free(m); + return (NULL); + } + + /* ar(1) archives aren't supported in RDWR mode. */ + if (c == ELF_C_RDWR && e->e_kind == ELF_K_AR) { + (void) elf_end(e); + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + + e->e_flags |= flags; + e->e_fd = fd; + e->e_cmd = c; + + return (e); +} + +Elf * +elf_begin(int fd, Elf_Cmd c, Elf *a) +{ + Elf *e; + + e = NULL; + + if (LIBELF_PRIVATE(version) == EV_NONE) { + LIBELF_SET_ERROR(SEQUENCE, 0); + return (NULL); + } + + switch (c) { + case ELF_C_NULL: + return (NULL); + + case ELF_C_WRITE: + /* + * The ELF_C_WRITE command is required to ignore the + * descriptor passed in. + */ + a = NULL; + break; + + case ELF_C_RDWR: + if (a != NULL) { /* not allowed for ar(1) archives. */ + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + /*FALLTHROUGH*/ + case ELF_C_READ: + /* + * Descriptor `a' could be for a regular ELF file, or + * for an ar(1) archive. If descriptor `a' was opened + * using a valid file descriptor, we need to check if + * the passed in `fd' value matches the original one. + */ + if (a && + ((a->e_fd != -1 && a->e_fd != fd) || c != a->e_cmd)) { + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + } + break; + + default: + LIBELF_SET_ERROR(ARGUMENT, 0); + return (NULL); + + } + + if (a == NULL) + e = _libelf_open_object(fd, c); + else if (a->e_kind == ELF_K_AR) + e = _libelf_ar_open_member(a->e_fd, c, a); + else + (e = a)->e_activations++; + + return (e); +} |