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Commit c857021b authored by Terraneo Federico's avatar Terraneo Federico
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Finished implementing waitpid, needs testing

parent c48166bd
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main.cpp
+ 5
− 3
View file @ c857021b
......@@ -25,12 +25,14 @@ int main()
Thread::create(ledThread,STACK_MIN);
ElfProgram prog(reinterpret_cast<const unsigned int*>(main_elf),main_elf_len);
for(;;)
for(int i=0;;i++)
{
getchar();
Process::create(prog);
pid_t child=Process::create(prog);
int ec;
pid_t pid=Process::wait(&ec);
pid_t pid;
if(i%2==0) pid=Process::wait(&ec);
else pid=Process::waitpid(child,&ec,0);
iprintf("Process %d terminated\n",pid);
if(WIFEXITED(ec))
{
......
miosix/kernel/process.cpp
+ 115
− 46
View file @ c857021b
......@@ -79,8 +79,13 @@ pid_t Process::create(const ElfProgram& program)
Lock<Mutex> l(procMutex);
proc->pid=getNewPid();
if(Thread::getCurrentThread()->proc!=0)
{
proc->ppid=Thread::getCurrentThread()->proc->pid;
else proc->ppid=0;
Thread::getCurrentThread()->proc->childs.push_back(proc.get());
} else {
proc->ppid=0;
kernelChilds.push_back(proc.get());
}
processes[proc->pid]=proc.get();
}
Thread *thr=Thread::createUserspace(Process::start,0,Thread::DEFAULT,
......@@ -89,6 +94,10 @@ pid_t Process::create(const ElfProgram& program)
{
Lock<Mutex> l(procMutex);
processes.erase(proc->pid);
if(Thread::getCurrentThread()->proc!=0)
{
Thread::getCurrentThread()->proc->childs.remove(proc.get());
} else kernelChilds.remove(proc.get());
throw runtime_error("Thread creation failed");
}
//Cannot throw bad_alloc due to the reserve in Process's constructor.
......@@ -113,61 +122,103 @@ pid_t Process::getppid(pid_t proc)
pid_t Process::waitpid(pid_t pid, int* exit, int options)
{
Lock<Mutex> l(procMutex);
pid_t result=-1;
Process *self=Thread::getCurrentThread()->proc;
if(self==0)
{
//The wait is performed by the kernel
if(pid<=0)
{
//Wait for a generic child process
Process *self=Thread::getCurrentThread()->proc;
pid_t ppid=self==0 ? 0 : self->pid;
multimap<pid_t,Process *>::iterator it=zombies.find(ppid);
if((options & WNOHANG) && it==zombies.end()) return 0;
while(it==zombies.end())
if(kernelZombies.empty() && (options & WNOHANG)) return 0;
while(kernelZombies.empty())
{
if(kernelChilds.empty()) return -1;
genericWaiting.wait(l);
it=zombies.find(ppid);
}
Process *joined=it->second;
Process *joined=kernelZombies.front();
kernelZombies.pop_front();
processes.erase(joined->pid);
if(joined->waitCount!=0) errorHandler(UNEXPECTED);
result=joined->pid;
if(exit!=0) *exit=joined->exitCode;
zombies.erase(it);
processes.erase(result);
pid_t result=joined->pid;
delete joined;
return result;
} else {
//Wait on a specific process
//Wait on a specific child process
map<pid_t,Process *>::iterator it=processes.find(pid);
if(it!=processes.end())
{
if(it==processes.end() || it->second->ppid!=0) return -1;
Process *joined=it->second;
if(joined->exitCode==-1)
if(joined->zombie==false)
{
//Process hasn't terminated yet
if(options & WNOHANG) return 0;
joined->waitCount++;
joined->waiting.wait(l);
joined->waitCount--;
if(joined->waitCount<0 || joined->exitCode==-1)
if(joined->waitCount<0 || joined->zombie==false)
errorHandler(UNEXPECTED);
}
result=joined->pid;
if(exit!=0) *exit=joined->exitCode;
//If multiple threads call waitpid on the same child, the last
//gets the return value, the other -1
pid_t result=-1;
if(joined->waitCount==0)
{
typedef typename multimap<pid_t,Process *>::iterator iterator;
pair<iterator,iterator> p=zombies.equal_range(joined->ppid);
for(iterator it=p.first;it!=p.second;++it)
if(exit!=0) *exit=joined->exitCode;
result=joined->pid;
kernelZombies.remove(joined);
processes.erase(joined->pid);
delete joined;
}
return result;
}
} else {
//The wait is performed by a process
if(pid<=0)
{
//Wait for a generic child process
if(self->zombies.empty() && (options & WNOHANG)) return 0;
while(self->zombies.empty())
{
if(it->second!=joined) continue;
zombies.erase(it);
break;
if(self->childs.empty()) return -1;
genericWaiting.wait(l);
}
processes.erase(result);
Process *joined=self->zombies.front();
self->zombies.pop_front();
processes.erase(joined->pid);
if(joined->waitCount!=0) errorHandler(UNEXPECTED);
if(exit!=0) *exit=joined->exitCode;
pid_t result=joined->pid;
delete joined;
return result;
} else {
//Wait on a specific child process
map<pid_t,Process *>::iterator it=processes.find(pid);
if(it==processes.end() || it->second->ppid!=self->pid
|| pid==self->pid) return -1;
Process *joined=it->second;
if(joined->zombie==false)
{
//Process hasn't terminated yet
if(options & WNOHANG) return 0;
joined->waitCount++;
joined->waiting.wait(l);
joined->waitCount--;
if(joined->waitCount<0 || joined->zombie==false)
errorHandler(UNEXPECTED);
}
}
pid_t result=-1;
if(joined->waitCount==0)
{
result=joined->pid;
if(exit!=0) *exit=joined->exitCode;
self->zombies.remove(joined);
processes.erase(joined->pid);
delete joined;
}
return result;
}
}
}
Process::~Process()
{
......@@ -177,7 +228,7 @@ Process::~Process()
}
Process::Process(const ElfProgram& program) : program(program), waitCount(0),
exitCode(-1)
zombie(false)
{
//This is required so that bad_alloc can never be thrown when the first
//thread of the process will be stored in this vector
......@@ -222,14 +273,13 @@ void *Process::start(void *argv)
#endif //__CODE_IN_XRAM
Thread::setupUserspaceContext(entry,proc->image.getProcessBasePointer(),
proc->image.getProcessImageSize());
int returnValue=0;
bool running=true;
do {
miosix_private::SyscallParameters sp=Thread::switchToUserspace();
if(proc->fault.faultHappened())
{
running=false;
returnValue=SIGSEGV; //Segfault
proc->exitCode=SIGSEGV; //Segfault
#ifdef WITH_ERRLOG
iprintf("Process %d terminated due to a fault\n"
"* Code base address was 0x%x\n"
......@@ -248,7 +298,7 @@ void *Process::start(void *argv)
{
case 2:
running=false;
returnValue=(sp.getFirstParameter() & 0xff)<<8;
proc->exitCode=(sp.getFirstParameter() & 0xff)<<8;
break;
case 3:
//FIXME: check that the pointer belongs to the process
......@@ -267,7 +317,7 @@ void *Process::start(void *argv)
break;
default:
running=false;
returnValue=SIGSYS; //Bad syscall
proc->exitCode=SIGSYS; //Bad syscall
#ifdef WITH_ERRLOG
iprintf("Unexpected syscall number %d\n",sp.getSyscallId());
#endif //WITH_ERRLOG
......@@ -278,12 +328,30 @@ void *Process::start(void *argv)
} while(running);
{
Lock<Mutex> l(procMutex);
proc->exitCode=returnValue;
proc->zombie=true;
list<Process*>::iterator it;
for(it=proc->childs.begin();it!=proc->childs.end();++it) (*it)->ppid=0;
for(it=proc->zombies.begin();it!=proc->zombies.end();++it) (*it)->ppid=0;
kernelChilds.splice(kernelChilds.begin(),proc->childs);
kernelZombies.splice(kernelZombies.begin(),proc->zombies);
if(proc->ppid!=0)
{
map<pid_t,Process *>::iterator it=processes.find(proc->ppid);
if(it==processes.end()) errorHandler(UNEXPECTED);
it->second->childs.remove(proc);
if(proc->waitCount>0) proc->waiting.broadcast();
else {
zombies.insert(make_pair(proc->ppid,proc));
it->second->zombies.push_back(proc);
genericWaiting.broadcast();
}
} else {
kernelChilds.remove(proc);
if(proc->waitCount>0) proc->waiting.broadcast();
else {
kernelZombies.push_back(proc);
genericWaiting.broadcast();
}
}
}
return 0;
}
......@@ -301,7 +369,8 @@ pid_t Process::getNewPid()
}
map<pid_t,Process*> Process::processes;
multimap<pid_t,Process *> Process::zombies;
std::list<Process *> Process::kernelChilds;
std::list<Process *> Process::kernelZombies;
pid_t Process::pidCounter=1;
Mutex Process::procMutex;
ConditionVariable Process::genericWaiting;
......
miosix/kernel/process.h
+ 7
− 3
View file @ c857021b
......@@ -30,6 +30,7 @@
#include <vector>
#include <map>
#include <list>
#include <sys/types.h>
#include "kernel.h"
#include "sync.h"
......@@ -122,6 +123,8 @@ private:
miosix_private::MPUConfiguration mpu; ///<Memory protection data
std::vector<Thread *> threads; ///<Threads that belong to the process
std::list<Process *> childs; ///<Living child processes are stored here
std::list<Process *> zombies; ///<Dead child processes are stored here
pid_t pid; ///<The pid of this process
pid_t ppid; ///<The parent pid of this process
///Contains the count of active wait calls which specifically requested
......@@ -130,12 +133,13 @@ private:
///Active wait calls which specifically requested to wait on this process
///wait on this condition variable
ConditionVariable waiting;
int exitCode; ///< Contains -1 if process is running, or the exit code
bool zombie; ///< True for terminated not yet joined processes
short int exitCode; ///< Contains the exit code
///Maps the pid to the Process instance. Includes zombie processes
static std::map<pid_t,Process *> processes;
///Terminated but not joined processes, the key is the parent's pid
static std::multimap<pid_t,Process *> zombies;
static std::list<Process *> kernelChilds;
static std::list<Process *> kernelZombies;
///Used to assign a new pid to a process
static pid_t pidCounter;
///Uset to guard access to processes and pidCounter
......
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