/* $OpenBSD: rdsetroot.c,v 1.9 2005/01/14 22:47:06 deraadt Exp $ */ /* $NetBSD: rdsetroot.c,v 1.2 1995/10/13 16:38:39 gwr Exp $ */ /* * Copyright (c) 1994 Gordon W. Ross * 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. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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. */ /* * Copy a ramdisk image into the space reserved for it. * Kernel variables: rd_root_size, rd_root_image */ #include <sys/types.h> #include <sys/file.h> #include <sys/mman.h> #include <stdio.h> #include <unistd.h> #include <a.out.h> struct exec head; char *file; /* Virtual addresses of the symbols we frob. */ long rd_root_image_va, rd_root_size_va; /* Offsets relative to start of data segment. */ long rd_root_image_off, rd_root_size_off; /* value in the location at rd_root_size_off */ int rd_root_size_val; /* pointers to pieces of mapped file */ char *dataseg; /* and lengths */ int data_len; int data_off; int data_pgoff; void find_rd_root_image(char *); __dead void usage(void); int main(int argc, char *argv[]) { int ch, fd, n, xflag; int *ip; xflag = 0; while ((ch = getopt(argc, argv, "x")) != -1) { switch (ch) { case 'x': xflag = 1; break; default: usage(); } } argc -= optind; argv += optind; if (argc != 1) usage(); file = argv[0]; fd = open(file, O_RDWR, 0644); if (fd < 0) { perror(file); exit(1); } n = read(fd, &head, sizeof(head)); if (n < sizeof(head)) { printf("%s: reading header\n", file); exit(1); } if (N_BADMAG(head)) { printf("%s: bad magic number\n", file); exit(1); } #ifdef DEBUG printf(" text: %9d\n", head.a_text); printf(" data: %9d\n", head.a_data); printf(" bss: %9d\n", head.a_bss); printf(" syms: %9d\n", head.a_syms); printf("entry: 0x%08X\n", head.a_entry); printf("trsiz: %9d\n", head.a_trsize); printf("drsiz: %9d\n", head.a_drsize); #endif if (head.a_syms <= 0) { printf("%s: no symbols\n", file); exit(1); } if (head.a_trsize || head.a_drsize) { printf("%s: has relocations\n", file); exit(1); } find_rd_root_image(file); /* * Map in the whole data segment. * The file offset needs to be page aligned. */ data_off = N_DATOFF(head); #ifdef BROKEN_NMAGIC /* * XXX it seems that our ld has a bug when generating NMAGIC files. * the data segment ends up one page too far into the file. */ if (N_GETMAGIC(head) == NMAGIC) data_off += __LDPGSZ; #endif data_len = head.a_data; /* align... */ data_pgoff = N_PAGSIZ(head) - 1; data_pgoff &= data_off; data_off -= data_pgoff; data_len += data_pgoff; /* map in in... */ dataseg = mmap(NULL, data_len, PROT_READ | PROT_WRITE, MAP_SHARED, fd, data_off); if (dataseg == MAP_FAILED) { printf("%s: can not map data seg\n", file); perror(file); exit(1); } dataseg += data_pgoff; /* * Find value in the location: rd_root_size */ ip = (int*) (dataseg + rd_root_size_off); rd_root_size_val = *ip; #ifdef DEBUG printf("rd_root_size val: 0x%08X (%d blocks)\n", rd_root_size_val, (rd_root_size_val >> 9)); #endif /* * Copy the symbol table and string table. */ #ifdef DEBUG printf("copying root image...\n"); #endif if (xflag) { n = write(STDOUT_FILENO, dataseg + rd_root_image_off, rd_root_size_val); if (n != rd_root_size_val) { perror("write"); exit(1); } } else { n = read(STDIN_FILENO, dataseg + rd_root_image_off, rd_root_size_val); if (n < 0) { perror("read"); exit(1); } msync(dataseg - data_pgoff, data_len, 0); } #ifdef DEBUG printf("...copied %d bytes\n", n); #endif close(fd); exit(0); } /* * Find locations of the symbols to patch. */ struct nlist wantsyms[] = { { "_rd_root_size", 0 }, { "_rd_root_image", 0 }, { NULL, 0 }, }; void find_rd_root_image(char *file) { int data_va, std_entry; if (nlist(file, wantsyms)) { printf("%s: no rd_root_image symbols?\n", file); exit(1); } std_entry = N_TXTADDR(head) + (head.a_entry & (N_PAGSIZ(head)-1)); data_va = N_DATADDR(head); if (head.a_entry != std_entry) { printf("%s: warning: non-standard entry point: 0x%08x\n", file, head.a_entry); printf("\texpecting entry=0x%X\n", std_entry); data_va += (head.a_entry - std_entry); } rd_root_size_off = wantsyms[0].n_value - data_va; rd_root_image_off = wantsyms[1].n_value - data_va; #ifdef DEBUG printf(".data segment va: 0x%08X\n", data_va); printf("rd_root_size va: 0x%08X\n", wantsyms[0].n_value); printf("rd_root_image va: 0x%08X\n", wantsyms[1].n_value); printf("rd_root_size off: 0x%08X\n", rd_root_size_off); printf("rd_root_image off: 0x%08X\n", rd_root_image_off); #endif /* * Sanity check locations of db_* symbols */ if (rd_root_image_off < 0 || rd_root_image_off >= head.a_data) { printf("%s: rd_root_image not in data segment?\n", file); exit(1); } if (rd_root_size_off < 0 || rd_root_size_off >= head.a_data) { printf("%s: rd_root_size not in data segment?\n", file); exit(1); } } __dead void usage(void) { extern char *__progname; fprintf(stderr, "usage: %s [-x] file_name\n", __progname); exit(1); }