/
parent.cpp
1239 lines (1045 loc) · 41.4 KB
/
parent.cpp
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/*
Fakeroot Next Generation - run command with fake root privileges
This program is copyrighted. Copyright information is available at the
AUTHORS file at the root of the source tree for the fakeroot-ng project
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "config.h"
#include <unordered_map>
#include <string.h>
#include <limits.h>
#include <sys/types.h>
#include <sys/ptrace.h>
#include <signal.h>
#include <fcntl.h>
#include <unistd.h>
#include "arch/platform.h"
#include "parent.h"
#include "syscalls.h"
#include "process.h"
#include "daemon.h"
// forward declaration of function
static bool handle_memory_allocation( int sc_num, pid_t pid, pid_state *state );
// Keep track of handled syscalls
static std::unordered_map<int, syscall_hook> syscalls;
// Keep track of the states for the various processes
template <class key, class data> class map_class : public std::unordered_map<key, data>
{
// Inherit everything, just disable the dangerous operator[]
public:
data &operator[] (const key &k)
{
return std::unordered_map<key,data>::operator[] (k);
}
const data &operator[] ( const key &k) const
{
return std::unordered_map<key,data>::operator[] (k);
}
};
static map_class<pid_t, pid_state> state;
size_t static_mem_size, shared_mem_size;
static std::unordered_map<pid_t, int> root_children; // Map of all root children
static int num_processes; // Number of running processes
// Definitions of some methods
pid_state::process_memory::~process_memory()
{
if( shared_mem_local!=MAP_FAILED ) {
if( munmap( (void*)(((int_ptr)shared_mem_local)-shared_overhead), shared_size )<0 ) {
// Log the error, but do not otherwise do anything interesting ...
dlog("~process_memory: munmap( %p, %lu ) failed with %s\n", (void*)(((int_ptr)shared_mem_local)-shared_overhead),
(unsigned long)shared_size, strerror(errno) );
// ... unless we're in debug mode :-)
dlog(NULL);
assert(false);
}
shared_mem_local=MAP_FAILED;
}
}
static void init_handlers()
{
// A macro for defining a system call with different syscall and handler names
#define DEF_SYS2( syscall, function ) syscalls[SYS_##syscall]=syscall_hook(sys_##function, #syscall)
// A macro fro defining a system call with the same syscall and handler names
#define DEF_SYS1( syscall ) DEF_SYS2( syscall, syscall )
DEF_SYS1(geteuid);
#if defined(SYS_geteuid32)
DEF_SYS2(geteuid32, geteuid);
#endif
DEF_SYS1(getuid);
#if defined(SYS_getuid32)
DEF_SYS2(getuid32, getuid);
#endif
DEF_SYS1(getegid);
#if defined(SYS_getegid32)
DEF_SYS2(getegid32, getegid);
#endif
DEF_SYS1(getgid);
#if defined(SYS_getgid32)
DEF_SYS2(getgid32, getgid);
#endif
DEF_SYS1(getresuid);
#if defined(SYS_getresuid32)
DEF_SYS2(getresuid32, getresuid);
#endif
DEF_SYS1(getresgid);
#if defined(SYS_getresgid32)
DEF_SYS2(getresgid32, getresgid);
#endif
DEF_SYS1(getgroups);
#if defined(SYS_getgroups32)
DEF_SYS2(getgroups32, getgroups);
#endif
DEF_SYS1(setuid);
#ifdef SYS_seteuid
DEF_SYS1(seteuid);
#endif
#ifdef SYS_seteuid32
DEF_SYS2(seteuid32, seteuid);
#endif
#ifdef SYS_setfsuid
DEF_SYS1(setfsuid);
#endif
#ifdef SYS_setfsuid32
DEF_SYS2(setfsuid32, setfsuid);
#endif
#ifdef SYS_setresuid
DEF_SYS1(setresuid);
#endif
#ifdef SYS_setresuid32
DEF_SYS2(setresuid32, setresuid);
#endif
DEF_SYS1(setreuid);
#ifdef SYS_setreuid32
DEF_SYS2(setreuid32, setreuid);
#endif
DEF_SYS1(setgid);
#ifdef SYS_setegid
DEF_SYS1(setegid);
#endif
#ifdef SYS_setegid32
DEF_SYS2(setegid32, setegid);
#endif
#ifdef SYS_setfsgid
DEF_SYS1(setfsgid);
#endif
#ifdef SYS_setfsgid32
DEF_SYS2(setfsgid32, setfsgid);
#endif
#ifdef SYS_setresgid
DEF_SYS1(setresgid);
#endif
#ifdef SYS_setresgid32
DEF_SYS2(setresgid32, setresgid);
#endif
DEF_SYS1(setregid);
#ifdef SYS_setregid32
DEF_SYS2(setregid32, setregid);
#endif
DEF_SYS1(setgroups);
#if defined(SYS_setgroups32)
DEF_SYS2(setgroups32, setgroups);
#endif
DEF_SYS1(fork);
DEF_SYS1(vfork);
#if defined(SYS_clone)
DEF_SYS1(clone);
#endif
// Execve is special cased
// DEF_SYS1(execve);
#if defined(SYS_sigreturn)
DEF_SYS1(sigreturn);
#endif
#if defined(SYS_rt_sigreturn)
DEF_SYS2(rt_sigreturn, sigreturn);
#endif
DEF_SYS1(setsid);
#if defined(SYS_wait4)
DEF_SYS1(wait4);
#endif
#if defined(SYS_waitpid)
DEF_SYS1(waitpid);
#endif
DEF_SYS1(ptrace);
DEF_SYS1(kill);
DEF_SYS1(stat);
#ifdef SYS_stat64
DEF_SYS2(stat64, stat);
#endif
DEF_SYS2(fstat, stat);
#ifdef SYS_fstat64
DEF_SYS2(fstat64, stat);
#endif
DEF_SYS2(lstat, stat);
#ifdef SYS_lstat64
DEF_SYS2(lstat64, stat);
#endif
#if defined(SYS_newfstatat) && HAVE_OPENAT
DEF_SYS2(newfstatat, fstatat64);
#endif
#if defined(SYS_fstatat64) && HAVE_OPENAT
DEF_SYS1(fstatat64);
#endif
DEF_SYS1(chown);
#if defined(SYS_chown32)
DEF_SYS2(chown32, chown);
#endif
DEF_SYS1(fchown);
#if defined(SYS_fchown32)
DEF_SYS2(fchown32, fchown);
#endif
DEF_SYS1(lchown);
#if defined(SYS_lchown32)
DEF_SYS2(lchown32, lchown);
#endif
#if defined(SYS_fchownat) && HAVE_OPENAT
DEF_SYS1(fchownat);
#endif
DEF_SYS1(chmod);
DEF_SYS1(fchmod);
#if defined(SYS_fchmodat) && HAVE_OPENAT
DEF_SYS1(fchmodat);
#endif
DEF_SYS1(mknod);
#if defined(SYS_mknodat) && HAVE_OPENAT
DEF_SYS1(mknodat);
#endif
DEF_SYS1(open);
#if defined(SYS_openat) && HAVE_OPENAT
DEF_SYS1(openat);
#endif
DEF_SYS1(mkdir);
#if defined(SYS_mkdirat) && HAVE_OPENAT
DEF_SYS1(mkdirat);
#endif
DEF_SYS1(symlink);
#if defined(SYS_mkdirat) && HAVE_OPENAT
DEF_SYS1(symlinkat);
#endif
DEF_SYS1(link);
#if defined(SYS_linkat) && HAVE_OPENAT
DEF_SYS1(linkat);
#endif
DEF_SYS1(unlink);
#if defined(SYS_unlinkat) && HAVE_OPENAT
DEF_SYS1(unlinkat);
#endif
DEF_SYS1(rename);
#if defined(SYS_renameat) && HAVE_OPENAT
DEF_SYS1(renameat);
#endif
DEF_SYS1(rmdir);
DEF_SYS2(readlink, generic_chroot_support_link_param1);
#if defined(SYS_renameat) && HAVE_OPENAT
DEF_SYS2(readlinkat, generic_chroot_link_at);
#endif
DEF_SYS2(truncate, generic_chroot_support_param1);
#ifdef SYS_truncate64
DEF_SYS2(truncate64, generic_chroot_support_param1);
#endif
DEF_SYS2(statfs, generic_chroot_support_param1); // XXX Should last link be resolved?
#ifdef SYS_statfs64
DEF_SYS2(statfs64, generic_chroot_support_param1); // XXX Should last link be resolved?
#endif
DEF_SYS2(chdir, generic_chroot_support_param1);
DEF_SYS2(access, generic_chroot_support_param1);
#if defined(SYS_faccessat) && HAVE_OPENAT
DEF_SYS2(faccessat, generic_chroot_at_link4);
#endif
DEF_SYS2(utime, generic_chroot_support_param1);
DEF_SYS2(utimes, generic_chroot_support_param1);
#ifdef SYS_setxattr
DEF_SYS2(setxattr, generic_chroot_support_param1);
DEF_SYS2(getxattr, generic_chroot_support_param1);
DEF_SYS2(listxattr, generic_chroot_support_param1);
DEF_SYS2(removexattr, generic_chroot_support_param1);
#endif
#ifdef SYS_lsetxattr
DEF_SYS2(lsetxattr, generic_chroot_support_link_param1);
DEF_SYS2(lgetxattr, generic_chroot_support_link_param1);
DEF_SYS2(llistxattr, generic_chroot_support_link_param1);
DEF_SYS2(lremovexattr, generic_chroot_support_link_param1);
#endif
#ifdef SYS_uselib
DEF_SYS2(uselib, generic_chroot_support_param1);
#endif
#ifdef SYS_inotify_add_watch
DEF_SYS2(inotify_add_watch, generic_chroot_support_param1);
#endif
#if defined(SYS_futimesat) && HAVE_OPENAT
DEF_SYS2(futimesat, generic_chroot_at);
#endif
#if defined(SYS_utimensat) && HAVE_OPENAT
DEF_SYS2(utimensat, generic_chroot_at_link4);
#endif
DEF_SYS1(chroot);
DEF_SYS1(getcwd);
DEF_SYS1(mmap);
#ifdef SYS_mmap2
DEF_SYS2(mmap2, mmap);
#endif
DEF_SYS1(munmap);
}
void init_globals()
{
size_t page_size=sysconf(_SC_PAGESIZE);
static_mem_size=page_size;
shared_mem_size=2*PATH_MAX+ptlib_prepare_memory_len();
// Round this to the higher page size
shared_mem_size+=page_size-1;
shared_mem_size-=shared_mem_size%page_size;
}
// Debug related functions
static const char *sig2str( int signum )
{
static char buffer[64];
switch(signum) {
#define SIGNAME(a) case a: return #a;
SIGNAME(SIGHUP);
SIGNAME(SIGINT);
SIGNAME(SIGQUIT);
SIGNAME(SIGILL);
SIGNAME(SIGTRAP);
SIGNAME(SIGABRT);
SIGNAME(SIGBUS);
SIGNAME(SIGFPE);
SIGNAME(SIGKILL);
SIGNAME(SIGSEGV);
SIGNAME(SIGPIPE);
SIGNAME(SIGALRM);
SIGNAME(SIGTERM);
SIGNAME(SIGCHLD);
SIGNAME(SIGCONT);
SIGNAME(SIGSTOP);
#undef SIGNAME
default:
sprintf(buffer, "signal %d", signum);
}
return buffer;
}
static const char *state2str( pid_state::states state )
{
static char buffer[64];
switch(state) {
#define STATENAME(a) case pid_state::a: return #a;
STATENAME(INIT)
STATENAME(NONE)
STATENAME(RETURN)
STATENAME(REDIRECT1)
STATENAME(REDIRECT2)
STATENAME(REDIRECT3)
STATENAME(ALLOCATE)
STATENAME(ALLOC_RETURN)
STATENAME(WAITING)
STATENAME(ZOMBIE)
#undef STATENAME
}
sprintf(buffer, "Unknown state %d", state);
return buffer;
}
void dump_registers( pid_t pid )
{
if( log_level>0 ) {
void *state[PTLIB_STATE_SIZE];
ptlib_save_state( pid, state );
for( unsigned int i=0; i<PTLIB_STATE_SIZE; ++i )
dlog("state[%d]=%p\n", i, state[i]);
}
}
// State handling functions
static void notify_parent( pid_t parent, const pid_state::wait_state &waiting )
{
if( parent==1 || parent==0 ) {
// This process has no parent, or had a parent that already quit
return;
}
dlog("notify_parent: " PID_F " sent a notify about " PID_F "(%x)\n", parent, waiting.pid(), waiting.status());
pid_state *proc_state=lookup_state(parent);
assert(proc_state!=NULL);
proc_state->waiting_signals.push_back( waiting );
// Is the parent currently waiting?
if( proc_state->state==pid_state::WAITING ) {
// Call the original function handler, now that it has something to do
if( syscalls[proc_state->orig_sc].func( -1, parent, proc_state ) ) {
dlog("notify_parent: " PID_F " released from wait\n", parent);
ptlib_continue(PTRACE_SYSCALL, parent, 0);
}
}
}
static void handle_exit( pid_t pid, int status, const struct rusage &usage )
{
// Let's see if the process doing the exiting is even registered
pid_state *proc_state=lookup_state(pid);
dlog(NULL);
assert(proc_state!=NULL);
// Set the process state to ZOMBIE with usage count of 1
proc_state->state=pid_state::ZOMBIE;
proc_state->context_state[0]=1;
dlog("%s: " PID_F " is now a zombie\n", __func__, pid );
pid_state *parent_state=lookup_state(proc_state->parent);
// Notify the parent
#if PTLIB_PARENT_CAN_WAIT
// If a parent can wait on a debugged child we need to notify it even if the child is being debugged,
// but only if it actually has a parent (i.e. - was not reparented to init)
// Of course, if the debugger IS the parent, there is no need to notify it twice
if( proc_state->parent!=0 && proc_state->parent!=1 )
#else
// If a parent cannot wait, we need to let it know ourselves only if it's not being debugged
if( (proc_state->debugger==0 || proc_state->debugger==proc_state->parent) && proc_state->parent!=0 && proc_state->parent!=1 )
#endif
{
proc_state->context_state[0]++; // Update use count
notify_parent( proc_state->parent, pid_state::wait_state( pid, status, &usage, false ) );
}
// Regardless of whether it is being notified or not, the parent's child num needs to be decreased
if( parent_state!=NULL ) {
parent_state->num_children--;
}
if( proc_state->debugger!=0 && proc_state->debugger!=proc_state->parent ) {
// The process was being debugged - notify the debugger as well
proc_state->context_state[0]++; // Update use count
notify_parent( proc_state->parent, pid_state::wait_state( pid, status, &usage, true ) );
state[proc_state->debugger].num_debugees--;
}
// Is any process a child of this process?
// We need to delete all child zombie processes. This means changing the list while scanning it.
// Instead, create a list of pids to delete
std::set<pid_t> need_delete;
for( std::unordered_map<pid_t, pid_state>::iterator i=state.begin(); i!=state.end(); ++i ) {
if( i->second.parent==pid ) {
dlog("Reparenting process %d to init from %d\n", i->first, pid);
i->second.parent=1;
if( i->second.state==pid_state::ZOMBIE ) {
// "init" should release it
need_delete.insert(i->first);
}
}
if( i->second.debugger==pid ) {
dlog("Detaching process %d from recursive debugger %d\n", i->first, pid );
i->second.debugger=0;
if( i->second.state==pid_state::ZOMBIE && i->second.parent!=pid ) {
// The process is in zombie state, pid is its debugger but not parent
need_delete.insert(i->first);
}
}
}
for( std::set<pid_t>::iterator i=need_delete.begin(); i!=need_delete.end(); ++i ) {
delete_state(*i);
}
// Delete the state from our end. The state is reference counted, so it may not actually be deleted just yet
delete_state(pid);
}
void handle_new_process( pid_t parent_id, pid_t child_id )
{
// Copy the session information
pid_state *child=&state[child_id]; // We actually want to create the state if it did not already exist
if( child->state!=pid_state::INIT ) {
// Due to platform incompatibilities and other issues, we may be called several times over the same
// child. Don't make a fuss - just return.
dlog("%s: Process " PID_F " already registered - not performing any operation\n", __FUNCTION__, child_id );
return;
}
dlog("%s: Registering " PID_F " with parent " PID_F "\n", __FUNCTION__, child_id, parent_id );
// The platform may want to init the process in some way
ptlib_prepare(child_id);
// If this is a new root process, we do not actually start monitoring it just yet.
if( parent_id!=-1 )
child->state=pid_state::NONE;
pid_state *parent=lookup_state(parent_id);
if( parent!=NULL ) {
// If this assert fails, we somehow created a -1 process - not good
dlog(NULL);
assert(parent_id!=-1);
// This process is not a root process - it has a parent
// Copy everything from the parent, except what you don't copy
*child=*parent;
int_ptr process_type=parent->context_state[0];
if( (process_type&NEW_PROCESS_SAME_PARENT)==0 )
child->parent=parent_id;
pid_state *child_parent=lookup_state(child->parent);
if( child_parent!=NULL ) {
child_parent->num_children++;
}
child->num_children=0;
child->num_debugees=0;
// Whether the VM was copied or shared, the new process has the same static and shared memory
// If the VM is not shared, setting shared_memory but not shared_mem_local is an indication that the
// old memory needs to be freed
if( (process_type&NEW_PROCESS_SAME_VM)==0 ) {
// The processes do not share the same VM
child->mem=ref_count<pid_state::process_memory>(new pid_state::process_memory);
child->mem->set_remote_static(parent->mem->get_mem());
/*
The remote shared pointer for the parent is also valid for the child, but it is the same memory,
not a copy.
Keep the "shared_memory" pointer valid, but the "shared_mem_local" will be NULL to signify this is
memory we need to munmap.
*/
child->mem->set_remote_shared( parent->mem->get_shared() );
}
if( (process_type&NEW_PROCESS_SAME_DEBUGGER)==0 ) {
// The process inherits the debugger from the parent
child->debugger=0;
child->trace_mode=TRACE_DETACHED;
}
} else {
// This is a root process - no parent. Set it with the real session ID
child->session_id=getsid(child_id);
child->root=ref_count<std::string>(new std::string());
}
num_processes++;
}
int process_sigchld( pid_t pid, enum PTLIB_WAIT_RET wait_state, int status, long ret )
{
long sig=0;
pid_state *proc_state=lookup_state(pid);
if( wait_state!=NEWPROCESS && proc_state==NULL ) {
// The process does not exist!
// Register it
pid_t parent_pid=ptlib_get_parent(pid);
dlog("Caught unknown new process " PID_F ", detected parent " PID_F "\n", pid, parent_pid );
dlog(NULL);
assert( parent_pid==0 || parent_pid==1 || state.find(parent_pid)!=state.end() ); // Make sure the parent is, indeed, ours
// Handle the process creation before handling the syscall return
process_sigchld( parent_pid, NEWPROCESS, status, pid );
// Handle the rest of the syscall as a return from a syscall
wait_state=SYSCALL;
proc_state=lookup_state(pid);
assert(proc_state!=NULL);
ret=proc_state->orig_sc;
}
switch(wait_state) {
case SYSCALL:
{
bool posttrap_always=false;
if( proc_state->state==pid_state::REDIRECT1 ) {
// REDIRECT1 is just a filler state between the previous call, where the arguments were set up and
// the call initiated, and the call's return (REDIRECT2). No need to actually call the handler
dlog(PID_F ": Calling syscall %ld redirected from %s\n", pid, ret, syscalls[proc_state->orig_sc].name );
proc_state->state=pid_state::REDIRECT2;
} else if( proc_state->state==pid_state::REDIRECT2 || proc_state->state==pid_state::REDIRECT3 ) {
// REDIRECT2 means a return from a syscall generated by us.
// REDIRECT3 means entering a syscall generated by us, but for which the handler function would like
// to be notified (unlike REDIRECT1 above, which is short circuited)
if( proc_state->orig_sc!=SYS_execve ) {
dlog(PID_F ": Called syscall %ld, redirected from %s\n", pid, ret, syscalls[proc_state->orig_sc].name );
if( !syscalls[proc_state->orig_sc].func( ret, pid, proc_state ) )
sig=-1; // Mark for ptrace not to continue the process
} else {
// Special handling of the execve case
dlog(PID_F ": Called syscall %ld, redirected from execve\n", pid, ret );
if( !sys_execve( ret, pid, proc_state, posttrap_always ) )
sig=-1;
}
} else {
if( proc_state->state==pid_state::ALLOCATE ) {
if( !handle_memory_allocation( ret, pid, proc_state ) )
sig=-1;
}
if( proc_state->state!=pid_state::ALLOCATE ) {
// Sanity check - returning from same syscall that got us in
if( proc_state->state==pid_state::RETURN && ret!=proc_state->orig_sc ) {
dlog("process " PID_F " orig_sc=%d actual sc=%ld state=%s\n", pid, proc_state->orig_sc, ret,
state2str(proc_state->state));
dlog(NULL);
assert( proc_state->state!=pid_state::RETURN || ret==proc_state->orig_sc );
}
if( proc_state->state==pid_state::NONE && proc_state->debugger!=0 && proc_state->trace_mode==TRACE_SYSCALL ) {
dlog(PID_F ": pre-syscall hook called for debugger " PID_F "\n", pid, proc_state->debugger );
// Notify the debugger before the syscall
proc_state->context_state[0]=wait_state;
proc_state->context_state[1]=status;
proc_state->context_state[2]=ret;
proc_state->trace_mode=TRACE_STOPPED1;
pid_state::wait_state waiting;
waiting.pid()=pid;
waiting.status()=status;
getrusage( RUSAGE_CHILDREN, &waiting.usage() ); // XXX BUG This is the wrong function!
waiting.debugonly()=true;
notify_parent( proc_state->debugger, waiting );
sig=-1; // We'll halt the program until the "debugger" decides what to do with it
} else if( !proc_state->mem->get_loc() && proc_state->state==pid_state::NONE && ret!=SYS_execve && ret!=SYS_exit ) {
// We need to allocate memory
// No point in allocating memory when we are just entering an execve that will get rid of it
if( !allocate_process_mem( pid, proc_state, ret ) )
sig=-1;
} else {
// No debugger or otherwise we need to go ahead with this syscall
if( (proc_state->trace_mode&TRACE_MASK2)==TRACE_STOPPED1 ) {
proc_state->trace_mode&=TRACE_MASK1;
// The debugger may have changed the system call to execute - we will respect it
ret=ptlib_get_syscall( pid );
}
if( proc_state->state==pid_state::NONE )
// Store the syscall type here (we are not in override)
proc_state->orig_sc=ret;
if( syscalls.find(ret)!=syscalls.end() ) {
dlog(PID_F ": Called %s(%s)\n", pid, syscalls[ret].name, state2str(proc_state->state));
if( !syscalls[ret].func( ret, pid, proc_state ) ) {
sig=-1; // Mark for ptrace not to continue the process
}
} else if( ret==SYS_execve ) {
dlog(PID_F ": Called execve(%s)\n", pid, state2str(proc_state->state));
if( !sys_execve(ret, pid, proc_state, posttrap_always ) )
sig=-1;
} else {
dlog(PID_F ": Unknown syscall %ld(%s)\n", pid, ret, state2str(proc_state->state));
if( proc_state->state==pid_state::NONE ) {
proc_state->state=pid_state::RETURN;
} else if( proc_state->state==pid_state::RETURN ) {
proc_state->state=pid_state::NONE;
}
}
}
}
}
// Check for post-syscall debugger callback
// If the system sends a SIGTRAP after a successful execve, the logic is entirely different
if( proc_state->debugger!=0 && (
(proc_state->state==pid_state::NONE && proc_state->trace_mode==TRACE_SYSCALL) ||
posttrap_always )
)
{
dlog(PID_F ": notify debugger " PID_F " about post-syscall hook\n", pid, proc_state->debugger );
proc_state->trace_mode=TRACE_STOPPED2;
pid_state::wait_state waiting;
waiting.pid()=pid;
waiting.status()=status;
getrusage( RUSAGE_CHILDREN, &waiting.usage() ); // XXX BUG This is the wrong function!
waiting.debugonly()=true;
notify_parent( proc_state->debugger, waiting );
sig=-1; // Halt process until "debugger" decides it can keep on going
}
}
break;
case SIGNAL:
dlog(PID_F ": Signal %s\n", pid, sig2str(ret));
if( proc_state->debugger==0 ) {
if( proc_state->state==pid_state::INIT ) {
// When a process is being debugged, it appears to receive a SIGSTOP after the PTRACE_ATTACH. We use
// that signal to synchronize the states of the debugee and us
if( ret==SIGSTOP ) {
dlog(PID_F ": initial signal of process\n", pid );
sig=0;
proc_state->state=pid_state::NONE;
} else {
dlog(PID_F ": received unexpected signal while in INIT mode\n", pid);
// Deliver the signal and continue the process - the SIGSTOP may yet be coming
ptrace( PTRACE_CONT, pid, ret, 0 );
sig=-1;
}
} else {
sig=ret;
}
} else {
// Pass the signal to the debugger
pid_state::wait_state waiting;
waiting.pid()=pid;
waiting.status()=status;
getrusage( RUSAGE_CHILDREN, &waiting.usage() ); // XXX BUG this is the wrong function!
waiting.debugonly()=true;
proc_state->trace_mode=TRACE_STOPPED2;
notify_parent( proc_state->debugger, waiting );
sig=-1;
}
break;
case EXIT:
case SIGEXIT:
{
if( wait_state==EXIT ) {
dlog(PID_F ": Exit with return code %ld\n", pid, ret);
} else {
dlog(PID_F ": Exit with %s\n", pid, sig2str(ret));
}
struct rusage rusage;
getrusage( RUSAGE_CHILDREN, &rusage );
handle_exit(pid, status, rusage );
// If this was a root child, we may need to perform notification of exit status
std::unordered_map<pid_t, int>::iterator root_child=root_children.find(pid);
if( root_child!=root_children.end() ) {
if( root_child->second!=-1 ) {
write( root_child->second, &status, sizeof(status) );
close( root_child->second );
}
root_children.erase(root_child);
}
num_processes--;
}
break;
case NEWPROCESS:
{
dlog(PID_F ": Created new child process %ld\n", pid, ret);
handle_new_process( pid, ret );
}
}
return sig;
}
bool attach_debugger( pid_t child )
{
dlog(NULL);
// Attach a debugger to the child
if( ptrace(PTRACE_ATTACH, child, 0, 0)!=0 ) {
dlog("Could not start trace of process " PID_F ": %s\n", child, strerror(errno) );
throw errno_exception( "Could not start trace of process" );
}
dlog("Debugger successfully attached to process " PID_F "\n", child );
// Child has started, and is debugged
// root_children[child]=socket; // Mark this as a root child
// XXX Above line disabled pending rewrite of "parent can't wait" code
handle_new_process( -1, child ); // No parent - a root process
return true;
}
// Do nothing signal handler for sigchld
static void sigchld_handler(int signum)
{
}
// Signify whether an alarm was received while we were waiting
static bool alarm_happened=false;
static void sigalrm_handler(int signum)
{
alarm_happened=true;
}
int process_children( daemonProcess *daemon )
{
// Initialize the ptlib library
ptlib_init();
init_handlers();
init_globals();
dlog( "Begin the process loop\n" );
// Prepare the signal masks so we do not lose SIGCHLD while we wait
struct sigaction action;
memset( &action, 0, sizeof( action ) );
action.sa_handler=sigchld_handler;
sigemptyset( &action.sa_mask );
action.sa_flags=0;
sigaction( SIGCHLD, &action, NULL );
action.sa_handler=sigalrm_handler;
sigaction( SIGALRM, &action, NULL );
sigset_t orig_signals, child_signals;
sigemptyset( &child_signals );
sigaddset( &child_signals, SIGCHLD );
sigaddset( &child_signals, SIGALRM );
sigprocmask( SIG_BLOCK, &child_signals, &orig_signals );
sigdelset( &orig_signals, SIGCHLD );
sigdelset( &orig_signals, SIGALRM );
bool clientsockets=true;
while(num_processes>0 || clientsockets) {
int status;
pid_t pid;
long ret;
ptlib_extra_data data;
enum PTLIB_WAIT_RET wait_state;
if( !ptlib_wait( &pid, &status, &data, true ) ) {
if( errno==EAGAIN || (errno==ECHILD && num_processes==0) ) {
clientsockets=daemon->handle_request( &orig_signals, num_processes>0 );
// Did an alarm signal arrive?
if( alarm_happened ) {
alarm_happened=false;
dump_states();
}
} else if( errno==ECHILD ) {
// We should never get here. If we have no more children, we should have known about it already
dlog( "BUG - ptlib_wait failed with %s while numchildren is still %d\n", strerror(errno), num_processes );
dlog(NULL);
num_processes=0;
} else {
dlog("ptlib_wait failed %d: %s\n", errno, strerror(errno) );
}
continue;
}
ret=ptlib_parse_wait( pid, status, &wait_state );
long sig=process_sigchld( pid, wait_state, status, ret );
// The show must go on
if( sig>=0 )
ptlib_continue(PTRACE_SYSCALL, pid, sig);
}
return 0;
}
bool allocate_process_mem( pid_t pid, pid_state *state, int sc_num )
{
dlog("allocate_process_mem: " PID_F " running syscall %d needs process memory\n", pid, sc_num );
state->orig_sc=sc_num;
// Save the old state
ptlib_save_state( pid, state->saved_state );
state->state=pid_state::ALLOCATE;
if( state->mem->get_shared()!=0 )
state->context_state[0]=20; // Internal allocation state
else
state->context_state[0]=0; // Internal allocation state
return handle_memory_allocation( sc_num, pid, state );
}
static bool allocate_shared_mem( pid_t pid, pid_state *state )
{
char filename[PATH_MAX];
const char *tmpdir=getenv("FAKEROOT_TMPDIR");
if( tmpdir==NULL )
tmpdir=getenv("TMPDIR");
if( tmpdir==NULL || strlen(tmpdir)>=PATH_MAX-sizeof("/fakeroot-ng.XXXXXX") )
tmpdir=DEFAULT_TMPDIR;
sprintf(filename, "%s/fakeroot-ng.XXXXXX", tmpdir);
int fd=mkstemp(filename);
if( fd==-1 ) {
dlog("allocate_shared_mem: " PID_F " Failed to create file %s: %s\n", pid, filename, strerror(errno) );
// We'll kill the process
ptlib_continue( PTRACE_KILL, pid, 0 );
return false; // Freeze the process until the signal arrives
}
// Make sure that the file is big enough, but create it sparse
ftruncate( fd, shared_mem_size );
// Map the file into the local address space
char *memory=(char *)mmap( NULL, shared_mem_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0 );
if( memory==MAP_FAILED ) {
dlog("allocate_shared_mem: " PID_F " filed to map file %s into memory: %s\n", pid, filename, strerror(errno) );
// Cleanup
close(fd);
unlink(filename);
ptlib_continue( PTRACE_KILL, pid, 0 );
return false;
}
// Fill in the memory with necessary commands and adjust the pointer
memcpy( memory, ptlib_prepare_memory(), ptlib_prepare_memory_len() );
// We need to remember the name of the temporary file so we can unlink it
strcpy(memory+ptlib_prepare_memory_len(), filename);
// Cleanup
close(fd);
// Set the shared memory class to know who we are
state->mem->set_local_addr(memory, shared_mem_size, ptlib_prepare_memory_len());
// The local shared memory is mapped. Now we need to map the remote end
// Generate a new system call
// Copy the instructions for generating a syscall to the newly created memory
ptlib_set_mem( pid, ptlib_prepare_memory(), state->mem->get_mem(), ptlib_prepare_memory_len() );
// Fill in the parameters to open the same file
ptlib_set_argument( pid, 1, state->mem->get_mem()+ptlib_prepare_memory_len() );
ptlib_set_string( pid, state->mem->get_loc_c(), state->mem->get_mem()+ptlib_prepare_memory_len() );
ptlib_set_argument( pid, 2, O_RDONLY );
return true;
}
// Table of states:
// Start states - if have nothing - 0
// if have static buffer and old shared buffer - 20
// First we define the various stages of the state machine:
static bool hma_state0( int sc_num, pid_t pid, pid_state *state )
{
// Translate the whatever call into an mmap to allocate the process local memory
ptlib_set_syscall( pid, PREF_MMAP );
ptlib_set_argument( pid, 1, 0 ); // start pointer
ptlib_set_argument( pid, 2, static_mem_size ); // Length of page(s)
ptlib_set_argument( pid, 3, (PROT_EXEC|PROT_READ|PROT_WRITE) ); // Protection - allow execute
ptlib_set_argument( pid, 4, (MAP_PRIVATE|MAP_ANONYMOUS) ); // Flags - anonymous memory allocation
ptlib_set_argument( pid, 5, -1 ); // File descriptor
ptlib_set_argument( pid, 6, 0 ); // Offset
return true;
}
static bool hma_state1( int sc_num, pid_t pid, pid_state *state )
{
// First step - mmap just returned