source: downloads/boost_1_34_1/tools/jam/src/execunix.c @ 29

/*
 * Copyright 1993, 1995 Christopher Seiwald.
 *
 * This file is part of Jam - see jam.c for Copyright information.
 */

# include "jam.h"
# include "lists.h"
# include "execcmd.h"
# include <errno.h>
# include <time.h>
# include <unistd.h> /* needed for vfork(), _exit() prototypes */

#if defined(sun) || defined(__sun) || defined(linux)
#include <wait.h>
#endif

# ifdef USE_EXECUNIX
# include <sys/times.h>

# ifdef NO_VFORK
# define vfork() fork()
# endif

/*
 * execunix.c - execute a shell script on UNIX/WinNT/OS2/AmigaOS
 *
 * If $(JAMSHELL) is defined, uses that to formulate execvp()/spawnvp().
 * The default is:
 *
 *      /bin/sh -c %            [ on UNIX/AmigaOS ]
 *      cmd.exe /c %            [ on OS2/WinNT ]
 *
 * Each word must be an individual element in a jam variable value.
 *
 * In $(JAMSHELL), % expands to the command string and ! expands to 
 * the slot number (starting at 1) for multiprocess (-j) invocations.
 * If $(JAMSHELL) doesn't include a %, it is tacked on as the last
 * argument.
 *
 * Don't just set JAMSHELL to /bin/sh or cmd.exe - it won't work!
 *
 * External routines:
 *      execcmd() - launch an async command execution
 *      execwait() - wait and drive at most one execution completion
 *
 * Internal routines:
 *      onintr() - bump intr to note command interruption
 *
 * 04/08/94 (seiwald) - Coherent/386 support added.
 * 05/04/94 (seiwald) - async multiprocess interface
 * 01/22/95 (seiwald) - $(JAMSHELL) support
 * 06/02/97 (gsar)    - full async multiprocess support for Win32
 */

static int intr = 0;
static int cmdsrunning = 0;
static void (*istat)( int );

static struct
{
        int     pid; /* on win32, a real process handle */
        void    (*func)( void *closure, int status, timing_info* );
        void    *closure;
} cmdtab[ MAXJOBS ] = {{0}};

/*
 * onintr() - bump intr to note command interruption
 */

void
onintr( int disp )
{
        intr++;
        printf( "...interrupted\n" );
}

/*
 * execcmd() - launch an async command execution
 */

void
execcmd( 
        char *string,
        void (*func)( void *closure, int status, timing_info* ),
        void *closure,
        LIST *shell )
{
        int pid;
        int slot;
        char *argv[ MAXARGC + 1 ];      /* +1 for NULL */

        /* Find a slot in the running commands table for this one. */

        for( slot = 0; slot < MAXJOBS; slot++ )
            if( !cmdtab[ slot ].pid )
                break;

        if( slot == MAXJOBS )
        {
            printf( "no slots for child!\n" );
            exit( EXITBAD );
        }


        /* Forumulate argv */
        /* If shell was defined, be prepared for % and ! subs. */
        /* Otherwise, use stock /bin/sh (on unix) or cmd.exe (on NT). */

        if( shell )
        {
            int i;
            char jobno[4];
            int gotpercent = 0;

            sprintf( jobno, "%d", slot + 1 );

            for( i = 0; shell && i < MAXARGC; i++, shell = list_next( shell ) )
            {
                switch( shell->string[0] )
                {
                case '%':       argv[i] = string; gotpercent++; break;
                case '!':       argv[i] = jobno; break;
                default:        argv[i] = shell->string;
                }
                if( DEBUG_EXECCMD )
                    printf( "argv[%d] = '%s'\n", i, argv[i] );
            }

            if( !gotpercent )
                argv[i++] = string;

            argv[i] = 0;
        }
        else
        {
            argv[0] = "/bin/sh";
            argv[1] = "-c";
            argv[2] = string;
            argv[3] = 0;
        }

        /* Catch interrupts whenever commands are running. */

        if( !cmdsrunning++ )
            istat = signal( SIGINT, onintr );

        /* Start the command */

        if ((pid = vfork()) == 0) 
        {
                execvp( argv[0], argv );
                _exit(127);
        }

        if( pid == -1 )
        {
            perror( "vfork" );
            exit( EXITBAD );
        }

        /* Save the operation for execwait() to find. */

        cmdtab[ slot ].pid = pid;
        cmdtab[ slot ].func = func;
        cmdtab[ slot ].closure = closure;

        /* Wait until we're under the limit of concurrent commands. */
        /* Don't trust globs.jobs alone. */

        while( cmdsrunning >= MAXJOBS || cmdsrunning >= globs.jobs )
            if( !execwait() )
                break;
}

/*
 * execwait() - wait and drive at most one execution completion
 */

int
execwait()
{
        int i;
        int status, w;
        int rstat;
    timing_info time;
    struct tms old_time, new_time;
    
        /* Handle naive make1() which doesn't know if cmds are running. */

        if( !cmdsrunning )
            return 0;

    times(&old_time);
    
        /* Pick up process pid and status */
        while( ( w = wait( &status ) ) == -1 && errno == EINTR )
                ;

        if( w == -1 )
        {
            printf( "child process(es) lost!\n" );
            perror("wait");
            exit( EXITBAD );
        }

    times(&new_time);

    time.system = (double)(new_time.tms_cstime - old_time.tms_cstime) / CLOCKS_PER_SEC;
    time.user = (double)(new_time.tms_cutime - old_time.tms_cutime) / CLOCKS_PER_SEC;
    
        /* Find the process in the cmdtab. */

        for( i = 0; i < MAXJOBS; i++ )
            if( w == cmdtab[ i ].pid )
                break;

        if( i == MAXJOBS )
        {
            printf( "waif child found!\n" );
            exit( EXITBAD );
        }

    
        /* Drive the completion */

        if( !--cmdsrunning )
            signal( SIGINT, istat );

        if( intr )
            rstat = EXEC_CMD_INTR;
        else if( w == -1 || status != 0 )
            rstat = EXEC_CMD_FAIL;
        else
            rstat = EXEC_CMD_OK;

        cmdtab[ i ].pid = 0;

        (*cmdtab[ i ].func)( cmdtab[ i ].closure, rstat, &time );

        return 1;
}

# if defined( OS_NT ) && !defined( __BORLANDC__ )

# define WIN32_LEAN_AND_MEAN

# include <windows.h>           /* do the ugly deed */

static int
my_wait( int *status )
{
        int i, num_active = 0;
        DWORD exitcode, waitcode;
        static HANDLE *active_handles = 0;

        if (!active_handles)
    {
            active_handles = (HANDLE *)malloc(globs.jobs * sizeof(HANDLE) );
        if ( DEBUG_PROFILE )
            profile_memory( globs.jobs * sizeof(HANDLE) );
    }

        /* first see if any non-waited-for processes are dead,
         * and return if so.
         */
        for ( i = 0; i < globs.jobs; i++ ) {
            if ( cmdtab[i].pid ) {
                if ( GetExitCodeProcess((HANDLE)cmdtab[i].pid, &exitcode) ) {
                    if ( exitcode == STILL_ACTIVE )
                        active_handles[num_active++] = (HANDLE)cmdtab[i].pid;
                    else {
                        CloseHandle((HANDLE)cmdtab[i].pid);
                        *status = (int)((exitcode & 0xff) << 8);
                        return cmdtab[i].pid;
                    }
                }
                else
                    goto FAILED;
            }
        }

        /* if a child exists, wait for it to die */
        if ( !num_active ) {
            errno = ECHILD;
            return -1;
        }
        waitcode = WaitForMultipleObjects( num_active,
                                           active_handles,
                                           FALSE,
                                           INFINITE );
        if ( waitcode != WAIT_FAILED ) {
            if ( waitcode >= WAIT_ABANDONED_0
                && waitcode < WAIT_ABANDONED_0 + num_active )
                i = waitcode - WAIT_ABANDONED_0;
            else
                i = waitcode - WAIT_OBJECT_0;
            if ( GetExitCodeProcess(active_handles[i], &exitcode) ) {
                CloseHandle(active_handles[i]);
                *status = (int)((exitcode & 0xff) << 8);
                return (int)active_handles[i];
            }
        }

FAILED:
        errno = GetLastError();
        return -1;
    
}

# endif /* NT && !__BORLANDC__ */

# endif /* USE_EXECUNIX */