linux/Documentation/lguest/lguest.c

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/* Simple program to layout "physical" memory for new lguest guest.
* Linked high to avoid likely physical memory. */
#define _LARGEFILE64_SOURCE
#define _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <err.h>
#include <stdint.h>
#include <stdlib.h>
#include <elf.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <stdbool.h>
#include <errno.h>
#include <ctype.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <time.h>
#include <netinet/in.h>
#include <net/if.h>
#include <linux/sockios.h>
#include <linux/if_tun.h>
#include <sys/uio.h>
#include <termios.h>
#include <getopt.h>
#include <zlib.h>
typedef unsigned long long u64;
typedef uint32_t u32;
typedef uint16_t u16;
typedef uint8_t u8;
#include "../../include/linux/lguest_launcher.h"
#include "../../include/asm-i386/e820.h"
#define PAGE_PRESENT 0x7 /* Present, RW, Execute */
#define NET_PEERNUM 1
#define BRIDGE_PFX "bridge:"
#ifndef SIOCBRADDIF
#define SIOCBRADDIF 0x89a2 /* add interface to bridge */
#endif
static bool verbose;
#define verbose(args...) \
do { if (verbose) printf(args); } while(0)
static int waker_fd;
static u32 top;
struct device_list
{
fd_set infds;
int max_infd;
struct lguest_device_desc *descs;
struct device *dev;
struct device **lastdev;
};
struct device
{
struct device *next;
struct lguest_device_desc *desc;
void *mem;
/* Watch this fd if handle_input non-NULL. */
int fd;
bool (*handle_input)(int fd, struct device *me);
/* Watch DMA to this key if handle_input non-NULL. */
unsigned long watch_key;
u32 (*handle_output)(int fd, const struct iovec *iov,
unsigned int num, struct device *me);
/* Device-specific data. */
void *priv;
};
static int open_or_die(const char *name, int flags)
{
int fd = open(name, flags);
if (fd < 0)
err(1, "Failed to open %s", name);
return fd;
}
static void *map_zeroed_pages(unsigned long addr, unsigned int num)
{
static int fd = -1;
if (fd == -1)
fd = open_or_die("/dev/zero", O_RDONLY);
if (mmap((void *)addr, getpagesize() * num,
PROT_READ|PROT_WRITE|PROT_EXEC, MAP_FIXED|MAP_PRIVATE, fd, 0)
!= (void *)addr)
err(1, "Mmaping %u pages of /dev/zero @%p", num, (void *)addr);
return (void *)addr;
}
/* Find magic string marking entry point, return entry point. */
static unsigned long entry_point(void *start, void *end,
unsigned long page_offset)
{
void *p;
for (p = start; p < end; p++)
if (memcmp(p, "GenuineLguest", strlen("GenuineLguest")) == 0)
return (long)p + strlen("GenuineLguest") + page_offset;
err(1, "Is this image a genuine lguest?");
}
/* Returns the entry point */
static unsigned long map_elf(int elf_fd, const Elf32_Ehdr *ehdr,
unsigned long *page_offset)
{
void *addr;
Elf32_Phdr phdr[ehdr->e_phnum];
unsigned int i;
unsigned long start = -1UL, end = 0;
/* Sanity checks. */
if (ehdr->e_type != ET_EXEC
|| ehdr->e_machine != EM_386
|| ehdr->e_phentsize != sizeof(Elf32_Phdr)
|| ehdr->e_phnum < 1 || ehdr->e_phnum > 65536U/sizeof(Elf32_Phdr))
errx(1, "Malformed elf header");
if (lseek(elf_fd, ehdr->e_phoff, SEEK_SET) < 0)
err(1, "Seeking to program headers");
if (read(elf_fd, phdr, sizeof(phdr)) != sizeof(phdr))
err(1, "Reading program headers");
*page_offset = 0;
/* We map the loadable segments at virtual addresses corresponding
* to their physical addresses (our virtual == guest physical). */
for (i = 0; i < ehdr->e_phnum; i++) {
if (phdr[i].p_type != PT_LOAD)
continue;
verbose("Section %i: size %i addr %p\n",
i, phdr[i].p_memsz, (void *)phdr[i].p_paddr);
/* We expect linear address space. */
if (!*page_offset)
*page_offset = phdr[i].p_vaddr - phdr[i].p_paddr;
else if (*page_offset != phdr[i].p_vaddr - phdr[i].p_paddr)
errx(1, "Page offset of section %i different", i);
if (phdr[i].p_paddr < start)
start = phdr[i].p_paddr;
if (phdr[i].p_paddr + phdr[i].p_filesz > end)
end = phdr[i].p_paddr + phdr[i].p_filesz;
/* We map everything private, writable. */
addr = mmap((void *)phdr[i].p_paddr,
phdr[i].p_filesz,
PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_FIXED|MAP_PRIVATE,
elf_fd, phdr[i].p_offset);
if (addr != (void *)phdr[i].p_paddr)
err(1, "Mmaping vmlinux seg %i gave %p not %p",
i, addr, (void *)phdr[i].p_paddr);
}
return entry_point((void *)start, (void *)end, *page_offset);
}
/* This is amazingly reliable. */
static unsigned long intuit_page_offset(unsigned char *img, unsigned long len)
{
unsigned int i, possibilities[256] = { 0 };
for (i = 0; i + 4 < len; i++) {
/* mov 0xXXXXXXXX,%eax */
if (img[i] == 0xA1 && ++possibilities[img[i+4]] > 3)
return (unsigned long)img[i+4] << 24;
}
errx(1, "could not determine page offset");
}
static unsigned long unpack_bzimage(int fd, unsigned long *page_offset)
{
gzFile f;
int ret, len = 0;
void *img = (void *)0x100000;
f = gzdopen(fd, "rb");
while ((ret = gzread(f, img + len, 65536)) > 0)
len += ret;
if (ret < 0)
err(1, "reading image from bzImage");
verbose("Unpacked size %i addr %p\n", len, img);
*page_offset = intuit_page_offset(img, len);
return entry_point(img, img + len, *page_offset);
}
static unsigned long load_bzimage(int fd, unsigned long *page_offset)
{
unsigned char c;
int state = 0;
/* Ugly brute force search for gzip header. */
while (read(fd, &c, 1) == 1) {
switch (state) {
case 0:
if (c == 0x1F)
state++;
break;
case 1:
if (c == 0x8B)
state++;
else
state = 0;
break;
case 2 ... 8:
state++;
break;
case 9:
lseek(fd, -10, SEEK_CUR);
if (c != 0x03) /* Compressed under UNIX. */
state = -1;
else
return unpack_bzimage(fd, page_offset);
}
}
errx(1, "Could not find kernel in bzImage");
}
static unsigned long load_kernel(int fd, unsigned long *page_offset)
{
Elf32_Ehdr hdr;
if (read(fd, &hdr, sizeof(hdr)) != sizeof(hdr))
err(1, "Reading kernel");
if (memcmp(hdr.e_ident, ELFMAG, SELFMAG) == 0)
return map_elf(fd, &hdr, page_offset);
return load_bzimage(fd, page_offset);
}
static inline unsigned long page_align(unsigned long addr)
{
return ((addr + getpagesize()-1) & ~(getpagesize()-1));
}
/* initrd gets loaded at top of memory: return length. */
static unsigned long load_initrd(const char *name, unsigned long mem)
{
int ifd;
struct stat st;
unsigned long len;
void *iaddr;
ifd = open_or_die(name, O_RDONLY);
if (fstat(ifd, &st) < 0)
err(1, "fstat() on initrd '%s'", name);
len = page_align(st.st_size);
iaddr = mmap((void *)mem - len, st.st_size,
PROT_READ|PROT_EXEC|PROT_WRITE,
MAP_FIXED|MAP_PRIVATE, ifd, 0);
if (iaddr != (void *)mem - len)
err(1, "Mmaping initrd '%s' returned %p not %p",
name, iaddr, (void *)mem - len);
close(ifd);
verbose("mapped initrd %s size=%lu @ %p\n", name, st.st_size, iaddr);
return len;
}
static unsigned long setup_pagetables(unsigned long mem,
unsigned long initrd_size,
unsigned long page_offset)
{
u32 *pgdir, *linear;
unsigned int mapped_pages, i, linear_pages;
unsigned int ptes_per_page = getpagesize()/sizeof(u32);
/* If we can map all of memory above page_offset, we do so. */
if (mem <= -page_offset)
mapped_pages = mem/getpagesize();
else
mapped_pages = -page_offset/getpagesize();
/* Each linear PTE page can map ptes_per_page pages. */
linear_pages = (mapped_pages + ptes_per_page-1)/ptes_per_page;
/* We lay out top-level then linear mapping immediately below initrd */
pgdir = (void *)mem - initrd_size - getpagesize();
linear = (void *)pgdir - linear_pages*getpagesize();
for (i = 0; i < mapped_pages; i++)
linear[i] = ((i * getpagesize()) | PAGE_PRESENT);
/* Now set up pgd so that this memory is at page_offset */
for (i = 0; i < mapped_pages; i += ptes_per_page) {
pgdir[(i + page_offset/getpagesize())/ptes_per_page]
= (((u32)linear + i*sizeof(u32)) | PAGE_PRESENT);
}
verbose("Linear mapping of %u pages in %u pte pages at %p\n",
mapped_pages, linear_pages, linear);
return (unsigned long)pgdir;
}
static void concat(char *dst, char *args[])
{
unsigned int i, len = 0;
for (i = 0; args[i]; i++) {
strcpy(dst+len, args[i]);
strcat(dst+len, " ");
len += strlen(args[i]) + 1;
}
/* In case it's empty. */
dst[len] = '\0';
}
static int tell_kernel(u32 pgdir, u32 start, u32 page_offset)
{
u32 args[] = { LHREQ_INITIALIZE,
top/getpagesize(), pgdir, start, page_offset };
int fd;
fd = open_or_die("/dev/lguest", O_RDWR);
if (write(fd, args, sizeof(args)) < 0)
err(1, "Writing to /dev/lguest");
return fd;
}
static void set_fd(int fd, struct device_list *devices)
{
FD_SET(fd, &devices->infds);
if (fd > devices->max_infd)
devices->max_infd = fd;
}
/* When input arrives, we tell the kernel to kick lguest out with -EAGAIN. */
static void wake_parent(int pipefd, int lguest_fd, struct device_list *devices)
{
set_fd(pipefd, devices);
for (;;) {
fd_set rfds = devices->infds;
u32 args[] = { LHREQ_BREAK, 1 };
select(devices->max_infd+1, &rfds, NULL, NULL, NULL);
if (FD_ISSET(pipefd, &rfds)) {
int ignorefd;
if (read(pipefd, &ignorefd, sizeof(ignorefd)) == 0)
exit(0);
FD_CLR(ignorefd, &devices->infds);
} else
write(lguest_fd, args, sizeof(args));
}
}
static int setup_waker(int lguest_fd, struct device_list *device_list)
{
int pipefd[2], child;
pipe(pipefd);
child = fork();
if (child == -1)
err(1, "forking");
if (child == 0) {
close(pipefd[1]);
wake_parent(pipefd[0], lguest_fd, device_list);
}
close(pipefd[0]);
return pipefd[1];
}
static void *_check_pointer(unsigned long addr, unsigned int size,
unsigned int line)
{
if (addr >= top || addr + size >= top)
errx(1, "%s:%i: Invalid address %li", __FILE__, line, addr);
return (void *)addr;
}
#define check_pointer(addr,size) _check_pointer(addr, size, __LINE__)
/* Returns pointer to dma->used_len */
static u32 *dma2iov(unsigned long dma, struct iovec iov[], unsigned *num)
{
unsigned int i;
struct lguest_dma *udma;
udma = check_pointer(dma, sizeof(*udma));
for (i = 0; i < LGUEST_MAX_DMA_SECTIONS; i++) {
if (!udma->len[i])
break;
iov[i].iov_base = check_pointer(udma->addr[i], udma->len[i]);
iov[i].iov_len = udma->len[i];
}
*num = i;
return &udma->used_len;
}
static u32 *get_dma_buffer(int fd, void *key,
struct iovec iov[], unsigned int *num, u32 *irq)
{
u32 buf[] = { LHREQ_GETDMA, (u32)key };
unsigned long udma;
u32 *res;
udma = write(fd, buf, sizeof(buf));
if (udma == (unsigned long)-1)
return NULL;
/* Kernel stashes irq in ->used_len. */
res = dma2iov(udma, iov, num);
*irq = *res;
return res;
}
static void trigger_irq(int fd, u32 irq)
{
u32 buf[] = { LHREQ_IRQ, irq };
if (write(fd, buf, sizeof(buf)) != 0)
err(1, "Triggering irq %i", irq);
}
static void discard_iovec(struct iovec *iov, unsigned int *num)
{
static char discard_buf[1024];
*num = 1;
iov->iov_base = discard_buf;
iov->iov_len = sizeof(discard_buf);
}
static struct termios orig_term;
static void restore_term(void)
{
tcsetattr(STDIN_FILENO, TCSANOW, &orig_term);
}
struct console_abort
{
int count;
struct timeval start;
};
/* We DMA input to buffer bound at start of console page. */
static bool handle_console_input(int fd, struct device *dev)
{
u32 irq = 0, *lenp;
int len;
unsigned int num;
struct iovec iov[LGUEST_MAX_DMA_SECTIONS];
struct console_abort *abort = dev->priv;
lenp = get_dma_buffer(fd, dev->mem, iov, &num, &irq);
if (!lenp) {
warn("console: no dma buffer!");
discard_iovec(iov, &num);
}
len = readv(dev->fd, iov, num);
if (len <= 0) {
warnx("Failed to get console input, ignoring console.");
len = 0;
}
if (lenp) {
*lenp = len;
trigger_irq(fd, irq);
}
/* Three ^C within one second? Exit. */
if (len == 1 && ((char *)iov[0].iov_base)[0] == 3) {
if (!abort->count++)
gettimeofday(&abort->start, NULL);
else if (abort->count == 3) {
struct timeval now;
gettimeofday(&now, NULL);
if (now.tv_sec <= abort->start.tv_sec+1) {
/* Make sure waker is not blocked in BREAK */
u32 args[] = { LHREQ_BREAK, 0 };
close(waker_fd);
write(fd, args, sizeof(args));
exit(2);
}
abort->count = 0;
}
} else
abort->count = 0;
if (!len) {
restore_term();
return false;
}
return true;
}
static u32 handle_console_output(int fd, const struct iovec *iov,
unsigned num, struct device*dev)
{
return writev(STDOUT_FILENO, iov, num);
}
static u32 handle_tun_output(int fd, const struct iovec *iov,
unsigned num, struct device *dev)
{
/* Now we've seen output, we should warn if we can't get buffers. */
*(bool *)dev->priv = true;
return writev(dev->fd, iov, num);
}
static unsigned long peer_offset(unsigned int peernum)
{
return 4 * peernum;
}
static bool handle_tun_input(int fd, struct device *dev)
{
u32 irq = 0, *lenp;
int len;
unsigned num;
struct iovec iov[LGUEST_MAX_DMA_SECTIONS];
lenp = get_dma_buffer(fd, dev->mem+peer_offset(NET_PEERNUM), iov, &num,
&irq);
if (!lenp) {
if (*(bool *)dev->priv)
warn("network: no dma buffer!");
discard_iovec(iov, &num);
}
len = readv(dev->fd, iov, num);
if (len <= 0)
err(1, "reading network");
if (lenp) {
*lenp = len;
trigger_irq(fd, irq);
}
verbose("tun input packet len %i [%02x %02x] (%s)\n", len,
((u8 *)iov[0].iov_base)[0], ((u8 *)iov[0].iov_base)[1],
lenp ? "sent" : "discarded");
return true;
}
static u32 handle_block_output(int fd, const struct iovec *iov,
unsigned num, struct device *dev)
{
struct lguest_block_page *p = dev->mem;
u32 irq, *lenp;
unsigned int len, reply_num;
struct iovec reply[LGUEST_MAX_DMA_SECTIONS];
off64_t device_len, off = (off64_t)p->sector * 512;
device_len = *(off64_t *)dev->priv;
if (off >= device_len)
err(1, "Bad offset %llu vs %llu", off, device_len);
if (lseek64(dev->fd, off, SEEK_SET) != off)
err(1, "Bad seek to sector %i", p->sector);
verbose("Block: %s at offset %llu\n", p->type ? "WRITE" : "READ", off);
lenp = get_dma_buffer(fd, dev->mem, reply, &reply_num, &irq);
if (!lenp)
err(1, "Block request didn't give us a dma buffer");
if (p->type) {
len = writev(dev->fd, iov, num);
if (off + len > device_len) {
ftruncate(dev->fd, device_len);
errx(1, "Write past end %llu+%u", off, len);
}
*lenp = 0;
} else {
len = readv(dev->fd, reply, reply_num);
*lenp = len;
}
p->result = 1 + (p->bytes != len);
trigger_irq(fd, irq);
return 0;
}
static void handle_output(int fd, unsigned long dma, unsigned long key,
struct device_list *devices)
{
struct device *i;
u32 *lenp;
struct iovec iov[LGUEST_MAX_DMA_SECTIONS];
unsigned num = 0;
lenp = dma2iov(dma, iov, &num);
for (i = devices->dev; i; i = i->next) {
if (i->handle_output && key == i->watch_key) {
*lenp = i->handle_output(fd, iov, num, i);
return;
}
}
warnx("Pending dma %p, key %p", (void *)dma, (void *)key);
}
static void handle_input(int fd, struct device_list *devices)
{
struct timeval poll = { .tv_sec = 0, .tv_usec = 0 };
for (;;) {
struct device *i;
fd_set fds = devices->infds;
if (select(devices->max_infd+1, &fds, NULL, NULL, &poll) == 0)
break;
for (i = devices->dev; i; i = i->next) {
if (i->handle_input && FD_ISSET(i->fd, &fds)) {
if (!i->handle_input(fd, i)) {
FD_CLR(i->fd, &devices->infds);
/* Tell waker to ignore it too... */
write(waker_fd, &i->fd, sizeof(i->fd));
}
}
}
}
}
static struct lguest_device_desc *
new_dev_desc(struct lguest_device_desc *descs,
u16 type, u16 features, u16 num_pages)
{
unsigned int i;
for (i = 0; i < LGUEST_MAX_DEVICES; i++) {
if (!descs[i].type) {
descs[i].type = type;
descs[i].features = features;
descs[i].num_pages = num_pages;
if (num_pages) {
map_zeroed_pages(top, num_pages);
descs[i].pfn = top/getpagesize();
top += num_pages*getpagesize();
}
return &descs[i];
}
}
errx(1, "too many devices");
}
static struct device *new_device(struct device_list *devices,
u16 type, u16 num_pages, u16 features,
int fd,
bool (*handle_input)(int, struct device *),
unsigned long watch_off,
u32 (*handle_output)(int,
const struct iovec *,
unsigned,
struct device *))
{
struct device *dev = malloc(sizeof(*dev));
/* Append to device list. */
*devices->lastdev = dev;
dev->next = NULL;
devices->lastdev = &dev->next;
dev->fd = fd;
if (handle_input)
set_fd(dev->fd, devices);
dev->desc = new_dev_desc(devices->descs, type, features, num_pages);
dev->mem = (void *)(dev->desc->pfn * getpagesize());
dev->handle_input = handle_input;
dev->watch_key = (unsigned long)dev->mem + watch_off;
dev->handle_output = handle_output;
return dev;
}
static void setup_console(struct device_list *devices)
{
struct device *dev;
if (tcgetattr(STDIN_FILENO, &orig_term) == 0) {
struct termios term = orig_term;
term.c_lflag &= ~(ISIG|ICANON|ECHO);
tcsetattr(STDIN_FILENO, TCSANOW, &term);
atexit(restore_term);
}
/* We don't currently require a page for the console. */
dev = new_device(devices, LGUEST_DEVICE_T_CONSOLE, 0, 0,
STDIN_FILENO, handle_console_input,
LGUEST_CONSOLE_DMA_KEY, handle_console_output);
dev->priv = malloc(sizeof(struct console_abort));
((struct console_abort *)dev->priv)->count = 0;
verbose("device %p: console\n",
(void *)(dev->desc->pfn * getpagesize()));
}
static void setup_block_file(const char *filename, struct device_list *devices)
{
int fd;
struct device *dev;
off64_t *device_len;
struct lguest_block_page *p;
fd = open_or_die(filename, O_RDWR|O_LARGEFILE|O_DIRECT);
dev = new_device(devices, LGUEST_DEVICE_T_BLOCK, 1,
LGUEST_DEVICE_F_RANDOMNESS,
fd, NULL, 0, handle_block_output);
device_len = dev->priv = malloc(sizeof(*device_len));
*device_len = lseek64(fd, 0, SEEK_END);
p = dev->mem;
p->num_sectors = *device_len/512;
verbose("device %p: block %i sectors\n",
(void *)(dev->desc->pfn * getpagesize()), p->num_sectors);
}
/* We use fnctl locks to reserve network slots (autocleanup!) */
static unsigned int find_slot(int netfd, const char *filename)
{
struct flock fl;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_len = 1;
for (fl.l_start = 0;
fl.l_start < getpagesize()/sizeof(struct lguest_net);
fl.l_start++) {
if (fcntl(netfd, F_SETLK, &fl) == 0)
return fl.l_start;
}
errx(1, "No free slots in network file %s", filename);
}
static void setup_net_file(const char *filename,
struct device_list *devices)
{
int netfd;
struct device *dev;
netfd = open(filename, O_RDWR, 0);
if (netfd < 0) {
if (errno == ENOENT) {
netfd = open(filename, O_RDWR|O_CREAT, 0600);
if (netfd >= 0) {
char page[getpagesize()];
memset(page, 0, sizeof(page));
write(netfd, page, sizeof(page));
}
}
if (netfd < 0)
err(1, "cannot open net file '%s'", filename);
}
dev = new_device(devices, LGUEST_DEVICE_T_NET, 1,
find_slot(netfd, filename)|LGUEST_NET_F_NOCSUM,
-1, NULL, 0, NULL);
/* We overwrite the /dev/zero mapping with the actual file. */
if (mmap(dev->mem, getpagesize(), PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_SHARED, netfd, 0) != dev->mem)
err(1, "could not mmap '%s'", filename);
verbose("device %p: shared net %s, peer %i\n",
(void *)(dev->desc->pfn * getpagesize()), filename,
dev->desc->features & ~LGUEST_NET_F_NOCSUM);
}
static u32 str2ip(const char *ipaddr)
{
unsigned int byte[4];
sscanf(ipaddr, "%u.%u.%u.%u", &byte[0], &byte[1], &byte[2], &byte[3]);
return (byte[0] << 24) | (byte[1] << 16) | (byte[2] << 8) | byte[3];
}
/* adapted from libbridge */
static void add_to_bridge(int fd, const char *if_name, const char *br_name)
{
int ifidx;
struct ifreq ifr;
if (!*br_name)
errx(1, "must specify bridge name");
ifidx = if_nametoindex(if_name);
if (!ifidx)
errx(1, "interface %s does not exist!", if_name);
strncpy(ifr.ifr_name, br_name, IFNAMSIZ);
ifr.ifr_ifindex = ifidx;
if (ioctl(fd, SIOCBRADDIF, &ifr) < 0)
err(1, "can't add %s to bridge %s", if_name, br_name);
}
static void configure_device(int fd, const char *devname, u32 ipaddr,
unsigned char hwaddr[6])
{
struct ifreq ifr;
struct sockaddr_in *sin = (struct sockaddr_in *)&ifr.ifr_addr;
memset(&ifr, 0, sizeof(ifr));
strcpy(ifr.ifr_name, devname);
sin->sin_family = AF_INET;
sin->sin_addr.s_addr = htonl(ipaddr);
if (ioctl(fd, SIOCSIFADDR, &ifr) != 0)
err(1, "Setting %s interface address", devname);
ifr.ifr_flags = IFF_UP;
if (ioctl(fd, SIOCSIFFLAGS, &ifr) != 0)
err(1, "Bringing interface %s up", devname);
if (ioctl(fd, SIOCGIFHWADDR, &ifr) != 0)
err(1, "getting hw address for %s", devname);
memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, 6);
}
static void setup_tun_net(const char *arg, struct device_list *devices)
{
struct device *dev;
struct ifreq ifr;
int netfd, ipfd;
u32 ip;
const char *br_name = NULL;
netfd = open_or_die("/dev/net/tun", O_RDWR);
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strcpy(ifr.ifr_name, "tap%d");
if (ioctl(netfd, TUNSETIFF, &ifr) != 0)
err(1, "configuring /dev/net/tun");
ioctl(netfd, TUNSETNOCSUM, 1);
/* You will be peer 1: we should create enough jitter to randomize */
dev = new_device(devices, LGUEST_DEVICE_T_NET, 1,
NET_PEERNUM|LGUEST_DEVICE_F_RANDOMNESS, netfd,
handle_tun_input, peer_offset(0), handle_tun_output);
dev->priv = malloc(sizeof(bool));
*(bool *)dev->priv = false;
ipfd = socket(PF_INET, SOCK_DGRAM, IPPROTO_IP);
if (ipfd < 0)
err(1, "opening IP socket");
if (!strncmp(BRIDGE_PFX, arg, strlen(BRIDGE_PFX))) {
ip = INADDR_ANY;
br_name = arg + strlen(BRIDGE_PFX);
add_to_bridge(ipfd, ifr.ifr_name, br_name);
} else
ip = str2ip(arg);
/* We are peer 0, ie. first slot. */
configure_device(ipfd, ifr.ifr_name, ip, dev->mem);
/* Set "promisc" bit: we want every single packet. */
*((u8 *)dev->mem) |= 0x1;
close(ipfd);
verbose("device %p: tun net %u.%u.%u.%u\n",
(void *)(dev->desc->pfn * getpagesize()),
(u8)(ip>>24), (u8)(ip>>16), (u8)(ip>>8), (u8)ip);
if (br_name)
verbose("attached to bridge: %s\n", br_name);
}
static void __attribute__((noreturn))
run_guest(int lguest_fd, struct device_list *device_list)
{
for (;;) {
u32 args[] = { LHREQ_BREAK, 0 };
unsigned long arr[2];
int readval;
/* We read from the /dev/lguest device to run the Guest. */
readval = read(lguest_fd, arr, sizeof(arr));
if (readval == sizeof(arr)) {
handle_output(lguest_fd, arr[0], arr[1], device_list);
continue;
} else if (errno == ENOENT) {
char reason[1024] = { 0 };
read(lguest_fd, reason, sizeof(reason)-1);
errx(1, "%s", reason);
} else if (errno != EAGAIN)
err(1, "Running guest failed");
handle_input(lguest_fd, device_list);
if (write(lguest_fd, args, sizeof(args)) < 0)
err(1, "Resetting break");
}
}
static struct option opts[] = {
{ "verbose", 0, NULL, 'v' },
{ "sharenet", 1, NULL, 's' },
{ "tunnet", 1, NULL, 't' },
{ "block", 1, NULL, 'b' },
{ "initrd", 1, NULL, 'i' },
{ NULL },
};
static void usage(void)
{
errx(1, "Usage: lguest [--verbose] "
"[--sharenet=<filename>|--tunnet=(<ipaddr>|bridge:<bridgename>)\n"
"|--block=<filename>|--initrd=<filename>]...\n"
"<mem-in-mb> vmlinux [args...]");
}
int main(int argc, char *argv[])
{
unsigned long mem = 0, pgdir, start, page_offset, initrd_size = 0;
int i, c, lguest_fd;
struct device_list device_list;
void *boot = (void *)0;
const char *initrd_name = NULL;
device_list.max_infd = -1;
device_list.dev = NULL;
device_list.lastdev = &device_list.dev;
FD_ZERO(&device_list.infds);
/* We need to know how much memory so we can allocate devices. */
for (i = 1; i < argc; i++) {
if (argv[i][0] != '-') {
mem = top = atoi(argv[i]) * 1024 * 1024;
device_list.descs = map_zeroed_pages(top, 1);
top += getpagesize();
break;
}
}
while ((c = getopt_long(argc, argv, "v", opts, NULL)) != EOF) {
switch (c) {
case 'v':
verbose = true;
break;
case 's':
setup_net_file(optarg, &device_list);
break;
case 't':
setup_tun_net(optarg, &device_list);
break;
case 'b':
setup_block_file(optarg, &device_list);
break;
case 'i':
initrd_name = optarg;
break;
default:
warnx("Unknown argument %s", argv[optind]);
usage();
}
}
if (optind + 2 > argc)
usage();
/* We need a console device */
setup_console(&device_list);
/* First we map /dev/zero over all of guest-physical memory. */
map_zeroed_pages(0, mem / getpagesize());
/* Now we load the kernel */
start = load_kernel(open_or_die(argv[optind+1], O_RDONLY),
&page_offset);
/* Map the initrd image if requested */
if (initrd_name) {
initrd_size = load_initrd(initrd_name, mem);
*(unsigned long *)(boot+0x218) = mem - initrd_size;
*(unsigned long *)(boot+0x21c) = initrd_size;
*(unsigned char *)(boot+0x210) = 0xFF;
}
/* Set up the initial linar pagetables. */
pgdir = setup_pagetables(mem, initrd_size, page_offset);
/* E820 memory map: ours is a simple, single region. */
*(char*)(boot+E820NR) = 1;
*((struct e820entry *)(boot+E820MAP))
= ((struct e820entry) { 0, mem, E820_RAM });
/* Command line pointer and command line (at 4096) */
*(void **)(boot + 0x228) = boot + 4096;
concat(boot + 4096, argv+optind+2);
/* Paravirt type: 1 == lguest */
*(int *)(boot + 0x23c) = 1;
lguest_fd = tell_kernel(pgdir, start, page_offset);
waker_fd = setup_waker(lguest_fd, &device_list);
run_guest(lguest_fd, &device_list);
}