int main(int argc, char **argv) {
int fd = -1;
char magicbuf[MAGIC_LEN], *restorename;
char *version = PACKAGE_VERSION;
restorename = argv[1];
if (argc == 1 || (strcmp(argv[1], "--help") == 0 && argc == 2)) {
printf("%s", theUsage);
return 1;
} else if (strcmp (argv[1], "--version") == 0 && argc == 2) {
printf("%s\n", (version[0] == '\0' ? "Standalone MTCP" : version));
return 1;
} else if (restorename[0] == '-' && restorename[1] == '\0') {
fd = 0; /* read from stdin */
} else { /* argv[1] should be a real filename */
if (-1 == (fd = open(restorename, O_RDONLY))) {
perror("open");
return 1; }
}
memset(magicbuf, 0, sizeof magicbuf);
readall(fd, magicbuf, MAGIC_LEN);
if (memcmp (magicbuf, "DMTCP_CHECKPOINT", MAGIC_LEN) == 0) {
while (memcmp(magicbuf, MAGIC, MAGIC_LEN) != 0) {
int i;
for (i = 0; i < MAGIC_LEN-1; i++)
magicbuf[i] = magicbuf[i+1];
magicbuf[MAGIC_LEN-1] = '\0'; /* MAGIC should be a string w/o '\0' */
if (0 == readall(fd, magicbuf+(MAGIC_LEN-1), 1)) /* if EOF */
break;
}
}
if (memcmp (magicbuf, MAGIC, MAGIC_LEN) != 0) {
char command[512];
fprintf (stderr, "readmtcp: Not an mtcp image; trying it as dmtcp image\n");
sprintf (command, "gzip -dc %s | %s -", restorename, argv[0]);
exit( system(command) );
}
/* Find where the restore image goes */
VA restore_begin;
size_t restore_size;
void *restore_start; /* will be bound to fnc, mtcp_restore_start */
void (*finishrestore) (void);
/* Set the resource limits for stack from saved values */
struct rlimit stack_rlimit;
#ifdef FAST_CKPT_RST_VIA_MMAP
Area area;
fastckpt_read_header(fd, &stack_rlimit, &area, (VA*) &restore_start);
restore_begin = area.addr;
restore_size = area.size;
finishrestore = (void*) fastckpt_get_finishrestore();
printf("mtcp_restart: saved stack resource limit:" \
" soft_lim: %lu, hard_lim: %lu\n",
stack_rlimit.rlim_cur, stack_rlimit.rlim_max);
printf("*** restored libmtcp.so\n");
printf("%p-%p rwxp %p 00:00 0 [libmtcp.so]\n",
restore_begin, restore_begin + restore_size, restore_begin);
printf("restore_start routine: %p\n", restore_start);
printf("*** finishrestore\n");
printf("finishrestore routine: %p\n", finishrestore);
#else
readcs (fd, CS_STACKRLIMIT); /* resource limit for stack */
readall(fd, &stack_rlimit, sizeof stack_rlimit);
printf("mtcp_restart: saved stack resource limit:" \
" soft_lim: %lu, hard_lim: %lu\n",
stack_rlimit.rlim_cur, stack_rlimit.rlim_max);
printf("*** restored libmtcp.so\n");
readcs (fd, CS_RESTOREBEGIN); /* beginning of checkpointed libmtcp.so image */
readall(fd, &restore_begin, sizeof restore_begin);
readcs (fd, CS_RESTORESIZE); /* size of checkpointed libmtcp.so image */
readall(fd, &restore_size, sizeof restore_size);
readcs (fd, CS_RESTORESTART);
readall(fd, &restore_start, sizeof restore_start);
readcs (fd, CS_RESTOREIMAGE);
skipfile (fd, restore_size);
printf("%p-%p rwxp %p 00:00 0 [libmtcp.so]\n",
restore_begin, restore_begin + restore_size, restore_begin);
printf("restore_start routine: %p\n", restore_start);
printf("*** finishrestore\n");
readcs (fd, CS_FINISHRESTORE);
readall(fd, &finishrestore, sizeof finishrestore);
printf("finishrestore routine: %p\n", finishrestore);
char linkbuf[FILENAMESIZE];
int fdnum, linklen ;
struct stat statbuf;
off_t offset;
printf("*** file descriptors\n");
readcs (fd, CS_FILEDESCRS);
while (1) {
/* Read parameters of next file to restore */
readall(fd, &fdnum, sizeof fdnum);
if (fdnum < 0) break;
readall(fd, &statbuf, sizeof statbuf);
readall(fd, &offset, sizeof offset);
readall(fd, &linklen, sizeof linklen);
if ((size_t)linklen >= sizeof linkbuf) {
printf ("filename too long %d\n", linklen);
exit(1);
}
readall(fd, linkbuf, linklen);
linkbuf[linklen] = '\0';
}
#endif
printf("*** memory sections\n");
while(1) {
Area area;
char cstype;
#ifdef FAST_CKPT_RST_VIA_MMAP
if (fastckpt_get_next_area_dscr(&area) == 0) break;
#else
readall(fd, &cstype, sizeof cstype);
if (cstype == CS_THEEND) break;
if (cstype != CS_AREADESCRIP) {
printf ("readmtcp: expected CS_AREADESCRIP but had %d\n", cstype);
exit(1);
}
readall(fd, &area, sizeof area);
readcs (fd, CS_AREACONTENTS);
#ifdef ANDROID
if ((area.prot & MTCP_PROT_SKIP_PAGE) != 0) {
printf("%p-%p %s skipped\n", area.addr, area.addr + area.size, area.name);
} else
#endif
if ((area.prot & MTCP_PROT_ZERO_PAGE) == 0) {
skipfile (fd, area.size);
}
#endif
printf("%p-%p %c%c%c%c %8x 00:00 0 %s\n",
area.addr, area.addr + area.size,
( area.prot & PROT_READ ? 'r' : '-' ),
( area.prot & PROT_WRITE ? 'w' : '-' ),
( area.prot & PROT_EXEC ? 'x' : '-' ),
( area.flags & MAP_SHARED ? 's'
: ( area.flags & MAP_ANONYMOUS ? 'p' : '-' ) ),
0, area.name);
}
printf("*** done\n");
close (fd);
mtcp_restore_cpfd = -1;
return 0;
}
int main (int argc, char *argv[], char *envp[])
{
char magicbuf[MAGIC_LEN], *restorename;
int fd, verify;
size_t restore_size, offset=0;
void *restore_begin, *restore_mmap;
void (*restore_start) (int fd, int verify, pid_t decomp_child_pid,
char *ckpt_newname, char *cmd_file,
char *argv[], char *envp[]);
char cmd_file[PATH_MAX+1];
char ckpt_newname[PATH_MAX+1] = "";
char **orig_argv = argv;
int orig_argc = argc;
environ = envp;
if (mtcp_sys_getuid() == 0 || mtcp_sys_geteuid() == 0) {
mtcp_printf("Running mtcp_restart as root is dangerous. Aborting.\n" \
"If you still want to do this (at your own risk)," \
" then modify mtcp/%s:%d and re-compile.\n",
__FILE__, __LINE__ - 4);
mtcp_abort();
}
// Turn off randomize_va (by re-exec'ing) or warn user if vdso_enabled is on.
mtcp_check_vdso_enabled();
fd = decomp_child_pid = -1;
verify = 0;
shift;
while (1) {
if (argc == 0 || (mtcp_strcmp(argv[0], "--help") == 0 && argc == 1)) {
mtcp_printf("%s", theUsage);
return (-1);
} else if (mtcp_strcmp (argv[0], "--version") == 0 && argc == 1) {
mtcp_printf("%s", VERSION_AND_COPYRIGHT_INFO);
return (-1);
} else if (mtcp_strcmp (argv[0], "--verify") == 0 && argc == 2) {
verify = 1;
restorename = argv[1];
break;
} else if (mtcp_strcmp (argv[0], "--offset") == 0 && argc >= 3) {
offset = mtcp_atoi(argv[1]);
shift; shift;
} else if (mtcp_strcmp (argv[0], "--fd") == 0 && argc >= 2) {
fd = mtcp_atoi(argv[1]);
shift; shift;
} else if (mtcp_strcmp (argv[0], "--gzip-child-pid") == 0 && argc >= 2) {
decomp_child_pid = mtcp_atoi(argv[1]);
shift; shift;
} else if (mtcp_strcmp (argv[0], "--rename-ckpt") == 0 && argc >= 2) {
mtcp_strncpy(ckpt_newname, argv[1], PATH_MAX);
shift; shift;
} else if (mtcp_strcmp (argv[0], "--stderr-fd") == 0 && argc >= 2) {
// If using with DMTCP/jassert, Pass in a non-standard stderr
dmtcp_info_stderr_fd = mtcp_atoi(argv[1]);
shift; shift;
} else if (mtcp_strcmp (argv[0], "--") == 0 && argc == 2) {
restorename = argv[1];
break;
} else if (argc == 1) {
restorename = argv[0];
break;
} else {
mtcp_printf("%s", theUsage);
return (-1);
}
}
// Restore argc and argv pointer
argv = orig_argv;
argc = orig_argc;
/* XXX XXX XXX:
* DO NOT USE mtcp_printf OR DPRINTF BEFORE THIS BLOCK, IT'S DANGEROUS AND
* CAN MESS UP YOUR PROCESSES BY WRITING GARBAGE TO THEIR STDERR FD,
* IF THEY ARE NOT USING IT AS STDERR.
* --Kapil
*/
if (fd != -1 && decomp_child_pid != -1) {
restorename = NULL;
} else if ((fd == -1 && decomp_child_pid != -1) ||
(offset != 0 && fd != -1)) {
mtcp_printf("%s", theUsage);
return (-1);
}
if (restorename) {
#if 1
if (mtcp_sys_access(restorename, R_OK) != 0 && mtcp_sys_errno == EACCES) {
MTCP_PRINTF("\nProcess does not have read permission for\n" \
" checkpoint image (%s).\n" \
" (Check file permissions, UIDs etc.)\n",
restorename);
mtcp_abort();
}
#else
struct stat buf;
int rc = mtcp_sys_stat(restorename, &buf);
if (rc == -1) {
MTCP_PRINTF("Error %d stat()'ing ckpt image %s.",
mtcp_sys_errno, restorename);
mtcp_abort();
} else if (buf.st_uid != mtcp_sys_getuid()) { /*Could also run if geteuid()
matches*/
MTCP_PRINTF("\nProcess uid (%d) doesn't match uid (%d) of\n" \
" checkpoint image (%s).\n" \
"This is dangerous. Aborting for security reasons.\n" \
"If you still want to do this, modify mtcp/%s:%d and"
" re-compile.\n",
mtcp_sys_getuid(), buf.st_uid, restorename,
__FILE__, __LINE__ - 5);
mtcp_abort();
}
#endif
}
if (mtcp_strlen(ckpt_newname) == 0 && restorename != NULL && offset != 0) {
mtcp_strncpy(ckpt_newname, restorename, PATH_MAX);
}
if (restorename!=NULL) fd = open_ckpt_to_read(restorename, envp);
if (offset>0) {
//skip into the file a bit
VA addr = (VA) mtcp_sys_mmap(0, offset, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (addr == MAP_FAILED) {
MTCP_PRINTF("mmap failed with error %d\n", mtcp_sys_errno);
mtcp_abort();
}
mtcp_readfile(fd, addr, offset);
if (mtcp_sys_munmap(addr, offset) == -1) {
MTCP_PRINTF("munmap failed with error %d\n", mtcp_sys_errno);
mtcp_abort();
}
}
mtcp_memset(magicbuf, 0, sizeof magicbuf);
mtcp_readfile (fd, magicbuf, MAGIC_LEN);
if (mtcp_memcmp (magicbuf, MAGIC, MAGIC_LEN) != 0) {
MTCP_PRINTF("'%s' is '%s', but this restore is '%s' (fd=%d)\n",
restorename, magicbuf, MAGIC, fd);
return (-1);
}
/* Set the resource limits for stack from saved values */
struct rlimit stack_rlimit;
#ifdef FAST_CKPT_RST_VIA_MMAP
Area area;
fastckpt_read_header(fd, &stack_rlimit, &area, (VA*) &restore_start);
restore_begin = area.addr;
restore_size = area.size;
#else
mtcp_readcs (fd, CS_STACKRLIMIT); /* resource limit for stack */
mtcp_readfile (fd, &stack_rlimit, sizeof stack_rlimit);
/* Find where the restore image goes */
mtcp_readcs (fd, CS_RESTOREBEGIN); /* beginning of checkpointed libmtcp.so image */
mtcp_readfile (fd, &restore_begin, sizeof restore_begin);
mtcp_readcs (fd, CS_RESTORESIZE); /* size of checkpointed libmtcp.so image */
mtcp_readfile (fd, &restore_size, sizeof restore_size);
mtcp_readcs (fd, CS_RESTORESTART);
mtcp_readfile (fd, &restore_start, sizeof restore_start);
DPRINTF("saved stack resource limit: soft_lim:%p, hard_lim:%p\n",
stack_rlimit.rlim_cur, stack_rlimit.rlim_max);
#endif // FAST_CKPT_RST_VIA_MMAP
mtcp_sys_setrlimit(RLIMIT_STACK, &stack_rlimit);
/* Read in the restore image to same address where it was loaded at time
* of checkpoint. This is libmtcp.so, including both text and data sections
* as a single section. Hence, we need both write and exec permission,
* and MAP_ANONYMOUS, since the data could have changed.
*/
DPRINTF("restoring anonymous area %p at %p\n", restore_size, restore_begin);
if (mtcp_sys_munmap(restore_begin, restore_size) < 0) {
MTCP_PRINTF("failed to unmap region at %p\n", restore_begin);
mtcp_abort ();
}
#ifdef FAST_CKPT_RST_VIA_MMAP
fastckpt_load_restore_image(fd, &area);
#else
restore_mmap = mtcp_safemmap (restore_begin, restore_size,
PROT_READ | PROT_WRITE | PROT_EXEC,
MAP_ANONYMOUS | MAP_FIXED | MAP_PRIVATE, -1, 0);
if (restore_mmap == MAP_FAILED) {
#ifndef _XOPEN_UNIX
MTCP_PRINTF("Does mmap here support MAP_FIXED?\n");
#endif
if (mtcp_sys_errno != EBUSY) {
MTCP_PRINTF("Error %d creating %p byte restore region at %p.\n",
mtcp_sys_errno, restore_size, restore_begin);
mtcp_abort ();
} else {
MTCP_PRINTF("restarting due to address conflict...\n");
mtcp_sys_close (fd);
mtcp_sys_execve (argv[0], argv, envp);
}
}
if (restore_mmap != restore_begin) {
MTCP_PRINTF("%p byte restore region at %p got mapped at %p\n",
restore_size, restore_begin, restore_mmap);
mtcp_abort ();
}
mtcp_readcs (fd, CS_RESTOREIMAGE);
mtcp_readfile (fd, restore_begin, restore_size);
#endif
#ifndef __x86_64__
// Copy command line to libmtcp.so, so that we can re-exec if randomized vdso
// steps on us. This won't be needed when we use the linker to map areas.
cmd_file[0] = '\0';
{ int cmd_len = mtcp_sys_readlink("/proc/self/exe", cmd_file, PATH_MAX);
if (cmd_len == -1)
MTCP_PRINTF("WARNING: Couldn't find /proc/self/exe."
" Trying to continue anyway.\n");
else
cmd_file[cmd_len] = '\0';
}
#endif
#ifdef LIBC_STATIC_AVAILABLE
/********************************************************************
* Apparently, there is no consistent way to define LIBC_STATIC_AVAILABLE.
* The purpose of the code below is to be able to use a symbolic debugger
* like gdb when dmtcp_restart calls MTCP. It would print a command that
* you can paste into gdb to allow debugging inside the function restore_start.
* When "ifdef LIBC_STATIC_AVAILABLE" was added, mtcp/Makefile was modified
* to forbid using functions from libc.a like popen. If you want to debug
* restore_start(), you should read the code below and manually calculate
* by hand what this used to automatically calculate. For a semi-automated
* substitute, when you reach restore_start(), call it with (gdb) si
* Then try: (gdb) shell ../utils/gdb-add-libmtcp-symbol-file.py
* where ADDR will be restore_start or an arb. address in restore_start()
********************************************************************/
# ifdef DEBUG
char *p, symbolbuff[256];
FILE *symbolfile;
long textbase; /* offset */
MTCP_PRINTF("restore_begin=%p, restore_start=%p\n",
restore_begin, restore_start);
textbase = 0;
symbolfile = popen ("readelf -S libmtcp.so", "r");
if (symbolfile != NULL) {
while (fgets (symbolbuff, sizeof symbolbuff, symbolfile) != NULL) {
if (memcmp (symbolbuff + 5, "] .text ", 8) == 0) {
textbase = strtoul (symbolbuff + 41, &p, 16);
}
}
pclose (symbolfile);
if (textbase != 0) {
mtcp_printf("\n**********\nmtcp_restart*: The symbol table of the"
" checkpointed file can be\nmade available to gdb."
" Just type the command below in gdb:\n");
mtcp_printf(" add-symbol-file libmtcp.so %p\n",
restore_begin + textbase);
mtcp_printf("Then type \"continue\" to continue debugging.\n");
mtcp_printf("**********\n");
}
}
mtcp_maybebpt ();
# endif
#endif
/* Now call it - it shouldn't return */
(*restore_start) (fd, verify, decomp_child_pid, ckpt_newname, cmd_file, argv, envp);
MTCP_PRINTF("restore routine returned (it should never do this!)\n");
mtcp_abort ();
return (0);
}