/*
 * Copyright (C) by Argonne National Laboratory
 *     See COPYRIGHT in top-level directory
 */

/* OWNER=gropp */

/* An example mpiexec program that simply forks new processes on the
   same host.  This provides a simple way to run MPI programs without
   requiring any special services.

   This code also shows how to use the pmutil routines (in ../util)
   to provide many of the services required by mpiexec

   Steps:
   1. Read and process that command line.  Build a ProcessList.  (A ProcessList
   may have one entry for a request to create n separate processes)

   2. Convert the ProcessList into a ProcessTable.  In the forker mpiexec,
   this simply expands the requested number of processes into an
   array with one entry per process.  These entries contain information
   on both the setup of the processes and the file descriptors used for
   stdin,out,err, and for the PMI calls.

   3. (Optionally) allow the forked processes to use a host:port to
   contact this program, rather than just sharing a pipe.  This also allows the
   forker to start other programs, such as debuggers.  To enable this feature,
   both the compile-time definition MPIEXEC_ALLOW_PORT and the environment
   variable MPIEXEC_USE_PORT must be set.

   4. Establish a signal handler for SIGCHLD.  This will allow us to
   get information about process termination; in particular, the exit
   status.

   5. Start the programs.

   6. Process input from the programs; send stdin given to this process
   to the selected processes (usually rank 0 or everyone).  Handle all
   PMI commands, including spawn.  Another "input" is the expiration of the
   specified timelimit for the run, if any.

   7. Process rundown commands and handle any abnormal termination.

   8. Wait for any processes to exit; gather the exit status and reason
   for exit (if abnormal, such as signaled with SEGV or BUS)

   9. Release all resources and compute the exit status for this program
   (using one of several approaches, such as taking the maximum of the
   exit statuses).

  Special Case to support Singleton Init:
  To support a singleton init of a process that then wants to
  create processes with MPI_Comm_spawn(_multiple), a special form of
  mpiexec is supported:

     mpiexec -pmi_args <port> <interfacename> <securitykey> <pid>

  The singleton process (in a routine in simple_pmi.c) forks a process and
  execs mpiexe with these arguments, where port is the port to which
  mpiexec should connect, interfacename is the name of the network interface, securitykey
  is a place-holder for a key used by the singleton init process to verify
  that the process connecting on the port is the one that was intended, and
  pid is the pid of the singleton init process.

  FIXME: The above has not been implemented yet.

*/

#include "mpichconf.h"
#include <stdio.h>
#include <string.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <stdlib.h>

#include "pmutil.h"
#include "process.h"
#include "cmnargs.h"
#include "pmiserv.h"
#include "ioloop.h"
#include "labelout.h"
#include "env.h"
#include "simple_pmiutil.h"

/* We can't use mpir_mem.h, because the memory routines are no longer available
   as utility routines, and instead now import properties from the device
   and other parts of the code */
/* mpir_mem.h contains prototypes for MPL_strncpy etc. */
/* #include "mpir_mem.h" */

typedef struct {
    PMISetup pmiinfo;
    IOLabelSetup labelinfo;
} SetupInfo;

/* Forward declarations */
int mypreamble(void *, ProcessState *);
int mypostfork(void *, void *, ProcessState *);
int mypostamble(void *, void *, ProcessState *);
int myspawn(ProcessWorld *, void *);

/* Set printFailure to 1 to get an explanation of the failure reason
   for each process when a process fails */
static int printFailure = 0;
/* Set usePort to 1 if a host:port should be used insted of inheriting
   an FD to a socketpair.  Meaningful only if code is compilete with
   -DMPIEXEC_ALLOW_PORT */
static int usePort = 0;

/* Note that envp is common but not standard */
int main(int argc, char *argv[], char *envp[])
{
    int rc;
    int erc = 0;                /* Other (exceptional) return codes */
    int reason, signaled = 0;
    SetupInfo s;

    /* MPIE_ProcessInit initializes the global pUniv */
    MPIE_ProcessInit();
    /* Set a default for the universe size */
    pUniv.size = 64;
    /* Tell the PMI untility routines that we are the server */
    PMIU_SetServer();

    /* Set defaults for any arguments that are options.  Also check the
     * environment for special options, such as debugging.  Set
     * some defaults in pUniv */
    MPIE_CheckEnv(&pUniv, 0, 0);
    IOLabelCheckEnv();

    /* Handle the command line arguments.  Use the routine from util/cmnargs.c
     * to fill in the universe */
    MPIE_Args(argc, argv, &pUniv, 0, 0);
    /* If there were any soft arguments, we need to handle them now */
    rc = MPIE_InitWorldWithSoft(&pUniv.worlds[0], pUniv.size);
    if (!rc) {
        MPL_error_printf("Unable to process soft arguments\n");
        exit(1);
    }

    if (pUniv.fromSingleton) {
        /* The MPI process is already running.  We create a simple entry
         * for a single process rather than creating the process */
        MPIE_SetupSingleton(&pUniv);
        /* The handshake to synchronize with the process happens below */
    }

    /* Here is where we would choose the hosts for the job; as gforker
     * uses same machine on which it runs, we don't perform this step */

    if (MPIE_Debug)
        MPIE_PrintProcessUniverse(stdout, &pUniv);

    DBG_PRINTF(("timeout_seconds = %d\n", pUniv.timeout));

    /* Note that a port is required if the singleton init approach
     * is supported */
#ifdef MPIEXEC_ALLOW_PORT
    /* Establish a host:port for use with the created processes.
     * In this code, the major use is to illustrate the use of a port for
     * connecting to processes rather than an FD that is inherited through the
     * fork and exec.  This could allow gforker to support the "singleton"
     * init, allowing an MPI process to contact a waiting mpiexec that
     * would serve as a process manager.  This option is not implemented */
    if (getenv("MPIEXEC_USE_PORT")) {
        s.pmiinfo.portName = (char *) MPL_malloc(1024, MPL_MEM_PM);
        if (!s.pmiinfo.portName) {
            MPL_error_printf("Failed to allocate storage for portName");
        }
        if (PMIServSetupPort(&pUniv, s.pmiinfo.portName, 1024)) {
            MPL_error_printf("Failed to setup a host:port\n");
        } else {
            usePort = 1;
        }
    } else {
        s.pmiinfo.portName = 0;
    }
#endif

    PMIServInit(myspawn, &s);
    s.pmiinfo.pWorld = &pUniv.worlds[0];
    PMISetupNewGroup(pUniv.worlds[0].nProcess, 0);
    /* PMISetupNewGroup will create a kvs space */
    MPIE_ForwardCommonSignals();
    MPIE_IgnoreSigPipe();

    if (!pUniv.fromSingleton) {
        MPIE_ForkProcesses(&pUniv.worlds[0], envp, mypreamble, &s, mypostfork, 0, mypostamble, 0);
        MPIE_InitForDebugger(&pUniv.worlds[0]);
    } else {
        int newfd;
        PMIProcess *pmiprocess = 0;
        ProcessState *pState = 0;
        /* We need to setup the connection to the provided process port */
        /* In the ForkProcesses version, the routine "mypreamble"
         * manages the creation of the PMI listener socket for
         * a connection back from the created process.  In this
         * version, we complete that connection by connecting directly
         * to the already-running process */
        newfd = MPIE_ConnectToPort(pUniv.singletonIfname, pUniv.singletonPort);
        if (newfd < 0) {
            /* Unable to connect */
            MPL_error_printf("Unable to connect to singleton process");
            exit(1);
        }
        pState = pUniv.worlds[0].apps->pState;
        /* FIXME: The following should be a single routine in pmiport */
        pmiprocess = PMISetupNewProcess(newfd, pState);

        PMI_InitSingletonConnection(newfd, pmiprocess);
        /* PMI_Init_port_connection is used with regular (as opposed to
         * singleton init) and is used to get the pmiid among other
         * items.  It isn't needed (and the commands aren't sent by the
         * client) in the singleton case */
        /*      PMI_Init_port_connection(newfd); */

        /* Init_remote_proc initiates the process of setting the rank and
         * debug flags.  This also isn't needed for the singleton init
         * case */
        /* PMI_Init_remote_proc(newfd, pmiprocess); */
        /* Ready to handle new input */
        MPIE_IORegister(newfd, IO_READ, PMIServHandleInput, pmiprocess);
    }

    /* Print out the proctable that is available to the debugger, through
     * the "MPIR" debugger interface. */
    if (MPIE_Debug) {
        MPIE_PrintDebuggerInfo(stdout);
    }

    reason = MPIE_IOLoop(pUniv.timeout);

    if (reason == IOLOOP_TIMEOUT) {
        /* Exited due to timeout.  Generate an error message and
         * terminate the children */
        if (pUniv.timeout > 60) {
            MPL_error_printf("Timeout of %d minutes expired; job aborted\n", pUniv.timeout / 60);
        } else {
            MPL_error_printf("Timeout of %d seconds expired; job aborted\n", pUniv.timeout);
        }
        erc = 1;
        MPIE_KillUniverse(&pUniv);
    }

    /* Wait for all processes to exit and gather information on them.
     * We do this through the SIGCHLD handler. We also bound the length
     * of time that we wait to 2 seconds.
     */
    MPIE_WaitForProcesses(&pUniv, 2);

    /* Compute the return code (max for now) */
    rc = MPIE_ProcessGetExitStatus(&signaled);

    /* Optionally provide detailed information about failed processes */
    /* For now, always print if a process died on an uncaught signal */
    if ((rc && printFailure) || signaled)
        MPIE_PrintFailureReasons(stderr);

    /* If the processes exited normally (or were already gone) but we
     * had an exceptional exit, such as a timeout, use the erc value */
    if (!rc && erc)
        rc = erc;

    /* In case you are running this under a memory analyzer, this call
     * will free any space allocated by the debugger interface */
    MPIE_FreeFromDebugger();

    return (rc);
}

void mpiexec_usage(const char *msg)
{
    if (msg) {
        MPL_error_printf("%s", msg);
        if (msg[strlen(msg) - 1] != '\n') {
            MPL_error_printf("\n");
        }
    }
    MPL_usage_printf("Usage: mpiexec %s\n", MPIE_ArgDescription());
    exit(-1);
}

/* ------------------------------------------------------------------------- */
/* Redirect stdout and stderr to a handler */
int mypreamble(void *data, ProcessState * pState)
{
    SetupInfo *s = (SetupInfo *) data;

    IOLabelSetupFDs(&s->labelinfo);
    /* In the inherit-FD case, this routine creates the FD that will
     * be used for PMI commands between the mpiexec process and the
     * fork/exec'ed process */
    PMISetupSockets(usePort, &s->pmiinfo);

    /* Tell MPIE_ForkProcesses not to include the PMI environment if
     * we are using a port, and use the PMI_PORT and ID instead */
    if (usePort)
        pState->initWithEnv = 0;

    /* Add clique information */
    {
        int i, size = pState->app->nProcess;
        char digits[10], ranks[1024];
        char key[256];

        /* Create the string of ranks.  These are ranks in comm_world */
        ranks[0] = 0;
        for (i = 0; i < size; i++) {
            MPL_snprintf(digits, sizeof(digits), "%d,", i);
            MPL_strnapp(ranks, digits, sizeof(ranks));
        }
        /* Remove the trailing comma */
        if (size > 0)
            ranks[strlen(ranks) - 1] = 0;
        /* Add this to the predefined keys */
        MPL_snprintf(key, sizeof(key), "pmiPrivateLocalRanks_%d", pState->wRank);
        /* printf("%s = %s\n", key, ranks); */

        pmix_preput(key, ranks);
    }

    return 0;
}

/* Close one side of each pipe pair and replace stdout/err with the pipes */
int mypostfork(void *predata, void *data, ProcessState * pState)
{
    SetupInfo *s = (SetupInfo *) predata;

    IOLabelSetupInClient(&s->labelinfo);
    PMISetupInClient(usePort, &s->pmiinfo);

    return 0;
}

/* Close one side of the pipe pair and register a handler for the I/O */
int mypostamble(void *predata, void *data, ProcessState * pState)
{
    SetupInfo *s = (SetupInfo *) predata;

    IOLabelSetupFinishInServer(&s->labelinfo, pState);
    PMISetupFinishInServer(usePort, &s->pmiinfo, pState);

    return 0;
}

int myspawn(ProcessWorld * pWorld, void *data)
{
    SetupInfo *s = (SetupInfo *) data;
    ProcessWorld *p, **pPtr;

    p = pUniv.worlds;
    pPtr = &(pUniv.worlds);
    while (p) {
        pPtr = &p->nextWorld;
        p = *pPtr;
    }
    *pPtr = pWorld;

    /* Fork Processes may call a routine that is passed s but not pWorld;
     * this makes sure that all routines can access the current world */
    s->pmiinfo.pWorld = pWorld;

    /* FIXME: This should be part of the PMI initialization in the clients */
    MPIE_Putenv(pWorld, "PMI_SPAWNED=1");
    MPIE_ForkProcesses(pWorld, 0, mypreamble, s, mypostfork, 0, mypostamble, 0);
    return 0;
}
