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536 lines
14 KiB
C
536 lines
14 KiB
C
/*-
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* Copyright (c) 1998 John D. Polstra
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/procfs.h>
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#include <sys/queue.h>
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#include <sys/linker_set.h>
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#include <machine/elf.h>
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#include <vm/vm_param.h>
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#include <vm/vm.h>
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#include <vm/pmap.h>
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#include <vm/vm_map.h>
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#include <err.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "extern.h"
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/*
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* Code for generating ELF core dumps.
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*/
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typedef void (*segment_callback)(vm_map_entry_t, void *);
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/* Closure for cb_put_phdr(). */
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struct phdr_closure {
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Elf_Phdr *phdr; /* Program header to fill in */
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Elf_Off offset; /* Offset of segment in core file */
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};
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/* Closure for cb_size_segment(). */
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struct sseg_closure {
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int count; /* Count of writable segments. */
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size_t size; /* Total size of all writable segments. */
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};
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static void cb_put_phdr(vm_map_entry_t, void *);
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static void cb_size_segment(vm_map_entry_t, void *);
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static void each_writable_segment(vm_map_entry_t, segment_callback,
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void *closure);
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static void elf_corehdr(int fd, pid_t, vm_map_entry_t, int numsegs,
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void *hdr, size_t hdrsize);
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static void elf_puthdr(vm_map_entry_t, void *, size_t *,
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const prstatus_t *, const prfpregset_t *, const prpsinfo_t *, int numsegs);
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static void elf_putnote(void *dst, size_t *off, const char *name, int type,
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const void *desc, size_t descsz);
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static void freemap(vm_map_entry_t);
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static void readhdrinfo(pid_t, prstatus_t *, prfpregset_t *, prpsinfo_t *);
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static vm_map_entry_t readmap(pid_t);
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static int
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elf_ident(int efd, pid_t pid __unused, char *binfile __unused)
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{
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Elf_Ehdr hdr;
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int cnt;
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cnt = read(efd, &hdr, sizeof(hdr));
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if (cnt != sizeof(hdr))
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return (0);
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if (IS_ELF(hdr))
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return (1);
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return (0);
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}
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/*
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* Write an ELF coredump for the given pid to the given fd.
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*/
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static void
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elf_coredump(int efd __unused, int fd, pid_t pid)
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{
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vm_map_entry_t map;
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struct sseg_closure seginfo;
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void *hdr;
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size_t hdrsize;
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char memname[64];
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int memfd;
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Elf_Phdr *php;
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int i;
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/* Get the program's memory map. */
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map = readmap(pid);
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/* Size the program segments. */
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seginfo.count = 0;
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seginfo.size = 0;
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each_writable_segment(map, cb_size_segment, &seginfo);
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/*
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* Calculate the size of the core file header area by making
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* a dry run of generating it. Nothing is written, but the
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* size is calculated.
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*/
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hdrsize = 0;
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elf_puthdr(map, (void *)NULL, &hdrsize,
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(const prstatus_t *)NULL, (const prfpregset_t *)NULL,
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(const prpsinfo_t *)NULL, seginfo.count);
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/*
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* Allocate memory for building the header, fill it up,
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* and write it out.
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*/
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if ((hdr = malloc(hdrsize)) == NULL)
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errx(1, "out of memory");
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elf_corehdr(fd, pid, map, seginfo.count, hdr, hdrsize);
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/* Write the contents of all of the writable segments. */
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snprintf(memname, sizeof memname, "/proc/%d/mem", pid);
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if ((memfd = open(memname, O_RDONLY)) == -1)
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err(1, "cannot open %s", memname);
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php = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr)) + 1;
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for (i = 0; i < seginfo.count; i++) {
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uintmax_t nleft = php->p_filesz;
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lseek(memfd, (off_t)php->p_vaddr, SEEK_SET);
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while (nleft > 0) {
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char buf[8*1024];
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size_t nwant;
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ssize_t ngot;
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if (nleft > sizeof(buf))
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nwant = sizeof buf;
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else
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nwant = nleft;
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ngot = read(memfd, buf, nwant);
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if (ngot == -1)
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err(1, "read from %s", memname);
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if ((size_t)ngot < nwant)
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errx(1, "short read from %s:"
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" wanted %zd, got %zd", memname,
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nwant, ngot);
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ngot = write(fd, buf, nwant);
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if (ngot == -1)
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err(1, "write of segment %d failed", i);
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if ((size_t)ngot != nwant)
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errx(1, "short write");
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nleft -= nwant;
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}
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php++;
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}
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close(memfd);
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free(hdr);
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freemap(map);
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}
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/*
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* A callback for each_writable_segment() to write out the segment's
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* program header entry.
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*/
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static void
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cb_put_phdr(vm_map_entry_t entry, void *closure)
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{
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struct phdr_closure *phc = (struct phdr_closure *)closure;
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Elf_Phdr *phdr = phc->phdr;
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phc->offset = round_page(phc->offset);
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phdr->p_type = PT_LOAD;
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phdr->p_offset = phc->offset;
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phdr->p_vaddr = entry->start;
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phdr->p_paddr = 0;
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phdr->p_filesz = phdr->p_memsz = entry->end - entry->start;
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phdr->p_align = PAGE_SIZE;
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phdr->p_flags = 0;
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if (entry->protection & VM_PROT_READ)
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phdr->p_flags |= PF_R;
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if (entry->protection & VM_PROT_WRITE)
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phdr->p_flags |= PF_W;
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if (entry->protection & VM_PROT_EXECUTE)
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phdr->p_flags |= PF_X;
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phc->offset += phdr->p_filesz;
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phc->phdr++;
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}
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/*
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* A callback for each_writable_segment() to gather information about
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* the number of segments and their total size.
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*/
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static void
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cb_size_segment(vm_map_entry_t entry, void *closure)
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{
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struct sseg_closure *ssc = (struct sseg_closure *)closure;
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ssc->count++;
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ssc->size += entry->end - entry->start;
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}
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/*
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* For each segment in the given memory map, call the given function
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* with a pointer to the map entry and some arbitrary caller-supplied
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* data.
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*/
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static void
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each_writable_segment(vm_map_entry_t map, segment_callback func, void *closure)
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{
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vm_map_entry_t entry;
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for (entry = map; entry != NULL; entry = entry->next)
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(*func)(entry, closure);
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}
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/*
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* Write the core file header to the file, including padding up to
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* the page boundary.
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*/
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static void
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elf_corehdr(int fd, pid_t pid, vm_map_entry_t map, int numsegs, void *hdr,
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size_t hdrsize)
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{
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size_t off;
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prstatus_t status;
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prfpregset_t fpregset;
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prpsinfo_t psinfo;
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/* Gather the information for the header. */
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readhdrinfo(pid, &status, &fpregset, &psinfo);
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/* Fill in the header. */
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memset(hdr, 0, hdrsize);
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off = 0;
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elf_puthdr(map, hdr, &off, &status, &fpregset, &psinfo, numsegs);
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/* Write it to the core file. */
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if (write(fd, hdr, hdrsize) == -1)
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err(1, "write");
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}
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/*
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* Generate the ELF coredump header into the buffer at "dst". "dst" may
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* be NULL, in which case the header is sized but not actually generated.
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*/
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static void
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elf_puthdr(vm_map_entry_t map, void *dst, size_t *off, const prstatus_t *status,
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const prfpregset_t *fpregset, const prpsinfo_t *psinfo, int numsegs)
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{
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size_t ehoff;
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size_t phoff;
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size_t noteoff;
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size_t notesz;
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ehoff = *off;
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*off += sizeof(Elf_Ehdr);
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phoff = *off;
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*off += (numsegs + 1) * sizeof(Elf_Phdr);
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noteoff = *off;
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elf_putnote(dst, off, "FreeBSD", NT_PRSTATUS, status,
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sizeof *status);
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elf_putnote(dst, off, "FreeBSD", NT_FPREGSET, fpregset,
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sizeof *fpregset);
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elf_putnote(dst, off, "FreeBSD", NT_PRPSINFO, psinfo,
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sizeof *psinfo);
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notesz = *off - noteoff;
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/* Align up to a page boundary for the program segments. */
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*off = round_page(*off);
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if (dst != NULL) {
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Elf_Ehdr *ehdr;
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Elf_Phdr *phdr;
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struct phdr_closure phc;
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/*
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* Fill in the ELF header.
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*/
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ehdr = (Elf_Ehdr *)((char *)dst + ehoff);
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ehdr->e_ident[EI_MAG0] = ELFMAG0;
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ehdr->e_ident[EI_MAG1] = ELFMAG1;
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ehdr->e_ident[EI_MAG2] = ELFMAG2;
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ehdr->e_ident[EI_MAG3] = ELFMAG3;
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ehdr->e_ident[EI_CLASS] = ELF_CLASS;
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ehdr->e_ident[EI_DATA] = ELF_DATA;
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ehdr->e_ident[EI_VERSION] = EV_CURRENT;
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ehdr->e_ident[EI_OSABI] = ELFOSABI_FREEBSD;
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ehdr->e_ident[EI_ABIVERSION] = 0;
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ehdr->e_ident[EI_PAD] = 0;
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ehdr->e_type = ET_CORE;
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ehdr->e_machine = ELF_ARCH;
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ehdr->e_version = EV_CURRENT;
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ehdr->e_entry = 0;
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ehdr->e_phoff = phoff;
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ehdr->e_flags = 0;
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ehdr->e_ehsize = sizeof(Elf_Ehdr);
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ehdr->e_phentsize = sizeof(Elf_Phdr);
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ehdr->e_phnum = numsegs + 1;
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ehdr->e_shentsize = sizeof(Elf_Shdr);
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ehdr->e_shnum = 0;
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ehdr->e_shstrndx = SHN_UNDEF;
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/*
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* Fill in the program header entries.
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*/
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phdr = (Elf_Phdr *)((char *)dst + phoff);
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/* The note segment. */
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phdr->p_type = PT_NOTE;
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phdr->p_offset = noteoff;
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phdr->p_vaddr = 0;
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phdr->p_paddr = 0;
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phdr->p_filesz = notesz;
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phdr->p_memsz = 0;
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phdr->p_flags = 0;
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phdr->p_align = 0;
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phdr++;
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/* All the writable segments from the program. */
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phc.phdr = phdr;
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phc.offset = *off;
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each_writable_segment(map, cb_put_phdr, &phc);
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}
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}
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/*
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* Emit one note section to "dst", or just size it if "dst" is NULL.
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*/
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static void
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elf_putnote(void *dst, size_t *off, const char *name, int type,
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const void *desc, size_t descsz)
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{
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Elf_Note note;
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note.n_namesz = strlen(name) + 1;
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note.n_descsz = descsz;
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note.n_type = type;
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if (dst != NULL)
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bcopy(¬e, (char *)dst + *off, sizeof note);
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*off += sizeof note;
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if (dst != NULL)
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bcopy(name, (char *)dst + *off, note.n_namesz);
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*off += roundup2(note.n_namesz, sizeof(Elf_Size));
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if (dst != NULL)
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bcopy(desc, (char *)dst + *off, note.n_descsz);
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*off += roundup2(note.n_descsz, sizeof(Elf_Size));
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}
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/*
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* Free the memory map.
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*/
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static void
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freemap(vm_map_entry_t map)
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{
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while (map != NULL) {
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vm_map_entry_t next = map->next;
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free(map);
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map = next;
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}
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}
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/*
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* Read the process information necessary to fill in the core file's header.
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*/
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static void
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readhdrinfo(pid_t pid, prstatus_t *status, prfpregset_t *fpregset,
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prpsinfo_t *psinfo)
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{
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char name[64];
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char line[256];
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int fd;
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int i;
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int n;
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memset(status, 0, sizeof *status);
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status->pr_version = PRSTATUS_VERSION;
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status->pr_statussz = sizeof(prstatus_t);
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status->pr_gregsetsz = sizeof(gregset_t);
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status->pr_fpregsetsz = sizeof(fpregset_t);
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status->pr_osreldate = __FreeBSD_version;
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status->pr_pid = pid;
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memset(fpregset, 0, sizeof *fpregset);
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memset(psinfo, 0, sizeof *psinfo);
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psinfo->pr_version = PRPSINFO_VERSION;
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psinfo->pr_psinfosz = sizeof(prpsinfo_t);
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/* Read the general registers. */
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snprintf(name, sizeof name, "/proc/%d/regs", pid);
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if ((fd = open(name, O_RDONLY)) == -1)
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err(1, "cannot open %s", name);
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if ((n = read(fd, &status->pr_reg, sizeof status->pr_reg)) == -1)
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err(1, "read error from %s", name);
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if ((size_t)n < sizeof(status->pr_reg))
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errx(1, "short read from %s: wanted %zd, got %d", name,
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sizeof status->pr_reg, n);
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close(fd);
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/* Read the floating point registers. */
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snprintf(name, sizeof name, "/proc/%d/fpregs", pid);
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if ((fd = open(name, O_RDONLY)) == -1)
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err(1, "cannot open %s", name);
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if ((n = read(fd, fpregset, sizeof *fpregset)) == -1)
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err(1, "read error from %s", name);
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if ((size_t)n < sizeof(*fpregset))
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errx(1, "short read from %s: wanted %zd, got %d", name,
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sizeof *fpregset, n);
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close(fd);
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/* Read and parse the process status. */
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snprintf(name, sizeof name, "/proc/%d/status", pid);
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if ((fd = open(name, O_RDONLY)) == -1)
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err(1, "cannot open %s", name);
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if ((n = read(fd, line, sizeof line - 1)) == -1)
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err(1, "read error from %s", name);
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if (n > MAXCOMLEN)
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n = MAXCOMLEN;
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for (i = 0; i < n && line[i] != ' '; i++)
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psinfo->pr_fname[i] = line[i];
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strncpy(psinfo->pr_psargs, psinfo->pr_fname, PRARGSZ);
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close(fd);
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}
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/*
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* Read the process's memory map using procfs, and return a list of
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* VM map entries. Only the non-device read/writable segments are
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* returned. The map entries in the list aren't fully filled in; only
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* the items we need are present.
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*/
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static vm_map_entry_t
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readmap(pid_t pid)
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{
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char mapname[64];
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int mapfd;
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ssize_t mapsize;
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size_t bufsize;
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char *mapbuf;
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int pos;
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vm_map_entry_t map;
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vm_map_entry_t *linkp;
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snprintf(mapname, sizeof mapname, "/proc/%d/map", pid);
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if ((mapfd = open(mapname, O_RDONLY)) == -1)
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err(1, "cannot open %s", mapname);
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/*
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* Procfs requires (for consistency) that the entire memory map
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* be read with a single read() call. Start with a reasonably sized
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* buffer, and double it until it is big enough.
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*/
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bufsize = 8 * 1024;
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mapbuf = NULL;
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for ( ; ; ) {
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if ((mapbuf = realloc(mapbuf, bufsize + 1)) == NULL)
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errx(1, "out of memory");
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mapsize = read(mapfd, mapbuf, bufsize);
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if (mapsize != -1 || errno != EFBIG)
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break;
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bufsize *= 2;
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/* This lseek shouldn't be necessary, but it is. */
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lseek(mapfd, (off_t)0, SEEK_SET);
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}
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if (mapsize == -1)
|
|
err(1, "read error from %s", mapname);
|
|
if (mapsize == 0)
|
|
errx(1, "empty map file %s", mapname);
|
|
mapbuf[mapsize] = 0;
|
|
close(mapfd);
|
|
|
|
pos = 0;
|
|
map = NULL;
|
|
linkp = ↦
|
|
while (pos < mapsize) {
|
|
vm_map_entry_t ent;
|
|
u_long start;
|
|
u_long end;
|
|
char prot[4];
|
|
char type[16];
|
|
int n;
|
|
int len;
|
|
|
|
len = 0;
|
|
n = sscanf(mapbuf + pos, "%lx %lx %*d %*d %*x %3[-rwx]"
|
|
" %*d %*d %*x %*s %*s %16s %*s%*[\n]%n",
|
|
&start, &end, prot, type, &len);
|
|
if (n != 4 || len == 0)
|
|
errx(1, "ill-formed line in %s starting at character %d", mapname, pos + 1);
|
|
pos += len;
|
|
|
|
/* Ignore segments of the wrong kind, and unwritable ones */
|
|
if (strncmp(prot, "rw", 2) != 0 ||
|
|
(strcmp(type, "default") != 0 &&
|
|
strcmp(type, "vnode") != 0 &&
|
|
strcmp(type, "swap") != 0))
|
|
continue;
|
|
|
|
if ((ent = (vm_map_entry_t)calloc(1, sizeof *ent)) == NULL)
|
|
errx(1, "out of memory");
|
|
ent->start = start;
|
|
ent->end = end;
|
|
ent->protection = VM_PROT_READ | VM_PROT_WRITE;
|
|
if (prot[2] == 'x')
|
|
ent->protection |= VM_PROT_EXECUTE;
|
|
|
|
*linkp = ent;
|
|
linkp = &ent->next;
|
|
}
|
|
free(mapbuf);
|
|
return map;
|
|
}
|
|
|
|
struct dumpers elfdump = { elf_ident, elf_coredump };
|
|
TEXT_SET(dumpset, elfdump);
|