1 /*
2 * Copyright (c) 2018-2021 Maxime Villard, m00nbsd.net
3 * All rights reserved.
4 *
5 * This code is part of the NVMM hypervisor.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/types.h>
30 #include <sys/stat.h>
31
32 #include <err.h>
33 #include <fcntl.h>
34 #include <stdint.h>
35 #include <stdio.h>
36 #include <stdlib.h>
37 #include <unistd.h>
38
39 #include "common.h"
40
41 #ifdef __NetBSD__
42 #define ELFSIZE 64
43 #include <sys/exec_elf.h>
44 #else /* DragonFly */
45 #include <sys/elf64.h>
46 #define Elf_Ehdr Elf64_Ehdr
47 #define Elf_Phdr Elf64_Phdr
48 #endif /* __NetBSD__ */
49
50 #define ELF_MAXPHNUM 128
51 #define ELF_MAXSHNUM 32768
52
53 static int
elf_check_header(Elf_Ehdr * eh)54 elf_check_header(Elf_Ehdr *eh)
55 {
56 if (eh->e_shnum > ELF_MAXSHNUM || eh->e_phnum > ELF_MAXPHNUM)
57 return -1;
58 return 0;
59 }
60
61 static uint64_t
elf_parse(struct nvmm_machine * mach,char * base)62 elf_parse(struct nvmm_machine *mach, char *base)
63 {
64 Elf_Ehdr *ehdr = (Elf_Ehdr *)base;
65 Elf_Phdr *phdr;
66 uintptr_t hva;
67 gpaddr_t lastgpa;
68 size_t i;
69
70 if (elf_check_header(ehdr) == -1)
71 errx(EXIT_FAILURE, "wrong ELF header");
72 phdr = (Elf_Phdr *)((char *)ehdr + ehdr->e_phoff);
73
74 for (i = 0; i < ehdr->e_phnum; i++) {
75 if (phdr[i].p_type != PT_LOAD) {
76 if (phdr[i].p_filesz == 0) {
77 /* Ignore zero-sized GNU_STACK segment
78 * (found on DragonFly) */
79 continue;
80 } else {
81 errx(EXIT_FAILURE, "unsupported ELF");
82 }
83 }
84
85 hva = toyvirt_mem_add(mach, phdr[i].p_vaddr,
86 roundup(phdr[i].p_filesz, PAGE_SIZE));
87 memcpy((void *)hva, base + phdr[i].p_offset, phdr[i].p_filesz);
88
89 lastgpa = phdr[i].p_vaddr +
90 roundup(phdr[i].p_filesz, PAGE_SIZE);
91 }
92
93 /* Add 128 pages after the kernel image. */
94 toyvirt_mem_add(mach, lastgpa, 128 * PAGE_SIZE);
95
96 return ehdr->e_entry;
97 }
98
99 int
elf_map(struct nvmm_machine * mach,const char * path,uint64_t * rip)100 elf_map(struct nvmm_machine *mach, const char *path, uint64_t *rip)
101 {
102 struct stat st;
103 char *base = NULL;
104 int fd, ret = -1;
105
106 fd = open(path, O_RDONLY);
107 if (fstat(fd, &st) == -1)
108 goto out;
109 if ((size_t)st.st_size < sizeof(Elf_Ehdr))
110 goto out;
111 base = malloc(st.st_size);
112 pread(fd, base, st.st_size, 0);
113
114 *rip = elf_parse(mach, base);
115 ret = 0;
116
117 out:
118 close(fd);
119 free(base);
120 return ret;
121 }
122