PyFCGI/src/ipc.c

#include "ipc.h"

static const char *semnames[] = PYFCGI_SEMNAMES;
static const pyfcgi_ipc_flag_t semflg[PYFCGI_NSEM] = {
	IPC_WSTATE, IPC_WREQS, IPC_SEMST};

void pyfcgi_name_IPC(pid_t master_pid)
{
	short i;
	for(i=0; i<PYFCGI_NSEM; i++)
	{
		if(snprintf(PyFCGI_conf.sems[i].name, NAME_MAX - 4,
			PYFCGI_IPCNAME_FMT, master_pid, semnames[i]) < 0)
		{
			perror("Error allocating semaphore names");
			exit(PYFCGI_FATAL);
		}
	}
	if(snprintf(PyFCGI_conf.shm.name, NAME_MAX, PYFCGI_IPCNAME_FMT,
		master_pid, "SHMstats") < 0)
	{
		perror("Error setting shm name");
		exit(PYFCGI_FATAL);
	}
	PyFCGI_conf.shm.len = sizeof(pyfcgi_stats_shm_t);
}

int pyfcgi_IPC_create(pyfcgi_ipc_flag_t flag)
{
	short i;
	int res, err;
	
	res = 0;
	for(i=0; i<PYFCGI_NSEM; i++)
	{
		if(flag & semflg[i])
		{
			flag ^= semflg[i];
			PyFCGI_SEM(i).sem = sem_open(PyFCGI_SEM(i).name,
				O_CREAT | O_EXCL, 0770, 0);
			if(PyFCGI_SEM(i).sem == SEM_FAILED)
			{
				err = errno;
				pyfcgi_log(LOG_ALERT,
					"Unable to create semaphore %s(named '%s') : %s",
					semnames[i], PyFCGI_SEM(i).name,
					strerror(err));
				PyFCGI_SEM(i).sem = NULL;
				res = -1;
			}
			else
			{
				PyFCGI_conf.context.ipc_flag |= semflg[i];
			}
		}
	}
	if(flag & IPC_SHMST)
	{
		flag ^= IPC_SHMST;
		PyFCGI_conf.shm.fd = shm_open(PyFCGI_conf.shm.name,
			O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
		if(PyFCGI_conf.shm.fd == -1)
		{
			err = errno;
			pyfcgi_log(LOG_ALERT,
				"Unable to create SHM '%s' : %s",
				PyFCGI_conf.shm.name, strerror(errno));
			PyFCGI_conf.shm.fd = 0;
			return -1;
		}
		PyFCGI_conf.context.ipc_flag |= IPC_SHMST;
		if(ftruncate(PyFCGI_conf.shm.fd,
			sizeof(pyfcgi_stats_shm_t)) < 0)
		{
			pyfcgi_log(LOG_ALERT,
				"Unable to truncate SHM to wanted size %ld : %s",
				sizeof(pyfcgi_stats_shm_t),
				strerror(errno));
			pyfcgi_IPC_destroy(IPC_SHMST);
			return -1;
		}
		PyFCGI_conf.shm.ptr = mmap(NULL, PyFCGI_conf.shm.len,
			PROT_READ | PROT_WRITE, MAP_SHARED, PyFCGI_conf.shm.fd,
			0);
		if(PyFCGI_conf.shm.ptr == (void*)-1)
		{
			pyfcgi_log(LOG_ALERT,
				"Unable to mmap SHM : %s", strerror(errno));
			pyfcgi_IPC_destroy(IPC_SHMST);
			return -1;
		}
		memset(PyFCGI_conf.shm.ptr, 0, PyFCGI_conf.shm.len);
	}
	return res;
}

int pyfcgi_IPC_init(pyfcgi_ipc_flag_t flag)
{
	short i;
	int res, err;
	
	res = 0;
	for(i=0; i<PYFCGI_NSEM; i++)
	{
		if(flag & semflg[i])
		{
			flag ^= semflg[i];
			PyFCGI_SEM(i).sem = sem_open(PyFCGI_SEM(i).name, 0);
			if(PyFCGI_SEM(i).sem == SEM_FAILED)
			{
				err = errno;
				pyfcgi_log(LOG_ALERT,
					"Unable to open semaphore %s(named '%s') : %s",
					semnames[i], PyFCGI_SEM(i).name,
					strerror(err));
				PyFCGI_SEM(i).sem = NULL;
				res = -1;
			}
			else
			{
				PyFCGI_conf.context.ipc_flag |= semflg[i];
			}
		}
	}
	if(flag & IPC_SHMST)
	{
		flag ^= IPC_SHMST;
		PyFCGI_conf.shm.fd = shm_open(PyFCGI_conf.shm.name, O_RDONLY,
			S_IRUSR | S_IWUSR);
		if(PyFCGI_conf.shm.fd == -1)
		{
			err = errno;
			pyfcgi_log(LOG_ALERT,
				"Unable to open SHM '%s' : %s",
				PyFCGI_conf.shm.name, strerror(errno));
			PyFCGI_conf.shm.fd = 0;
			return -1;
		}

		PyFCGI_conf.context.ipc_flag |= IPC_SHMST;
		PyFCGI_conf.shm.ptr = mmap(NULL, PyFCGI_conf.shm.len,
			PROT_READ, MAP_SHARED, PyFCGI_conf.shm.fd, 0);
		if(PyFCGI_conf.shm.ptr == (void*)-1)
		{
			pyfcgi_log(LOG_ALERT,
				"Unable to mmap SHM : %s", strerror(errno));
			pyfcgi_IPC_destroy(IPC_SHMST);
			return -1;
		}
	}
	return res;
}

int pyfcgi_IPC_close()
{
	short i;
	int res, err;
	pyfcgi_ipc_flag_t flag;

	flag = PyFCGI_conf.context.ipc_flag;
	res = 0;
	for(i=0; i<PYFCGI_NSEM; i++)
	{
		if(flag & semflg[i])
		{
			if(sem_close(PyFCGI_SEM(i).sem) < 0)
			{
				err = errno;
				pyfcgi_log(LOG_ALERT,
					"Unable to close semaphore %s('%s') : %s",
					semnames[i], PyFCGI_SEM(i).name,
					strerror(err));
				PyFCGI_SEM(i).sem = NULL;
			}
			PyFCGI_SEM(i).sem = NULL;
		}
	}
	if(flag & IPC_SHMST)
	{
		if(PyFCGI_conf.shm.ptr &&
			munmap(PyFCGI_conf.shm.ptr, PyFCGI_conf.shm.len) < 0)
		{
			pyfcgi_log(LOG_WARNING, "Unable to unmap SHM : %s",
				strerror(errno));
		}
		if(close(PyFCGI_conf.shm.fd) < 0)
		{
			pyfcgi_log(LOG_WARNING, "Unable to close SHM : %s",
				strerror(errno));
		}
		PyFCGI_conf.shm.fd = 0;
		PyFCGI_conf.shm.ptr = NULL;
		PyFCGI_conf.context.ipc_flag ^= IPC_SHMST;
	}

	return res;
}

int pyfcgi_IPC_destroy(pyfcgi_ipc_flag_t flag)
{
	short i;
	int err, res;
	
	res = 0;
	for(i=0; i<PYFCGI_NSEM; i++)
	{
		if(flag & semflg[i])
		{
			if(sem_unlink(PyFCGI_SEM(i).name) < 0)
			{
				err = errno;
				pyfcgi_log(LOG_ALERT,
					"Unable to unlink %s semaphore (%s) : %s",
					semnames[i], PyFCGI_SEM(i).name,
					strerror(err));
				res = -1;
			}
			PyFCGI_SEM(i).sem = NULL;
		}
	}
	if(flag & IPC_SHMST)
	{

		if(PyFCGI_conf.shm.ptr &&
			munmap(PyFCGI_conf.shm.ptr, PyFCGI_conf.shm.len) < 0)
		{
			pyfcgi_log(LOG_WARNING, "Unable to unmap SHM : %s",
				strerror(errno));
		}
		if(close(PyFCGI_conf.shm.fd) < 0)
		{
			pyfcgi_log(LOG_WARNING, "Unable to close SHM : %s",
				strerror(errno));
		}
		if(shm_unlink(PyFCGI_conf.shm.name) < 0)
		{
			pyfcgi_log(LOG_WARNING, "Unabe to unlink SHM : %s",
				strerror(errno));
		}
		PyFCGI_conf.shm.fd = 0;
		PyFCGI_conf.shm.ptr = NULL;
		PyFCGI_conf.context.ipc_flag ^= IPC_SHMST;
	}
	return res;
}