gpgme/gpgme/posix-io.c

/* posix-io.c - Posix I/O functions
 *	Copyright (C) 2000 Werner Koch (dd9jn)
 *
 * This file is part of GPGME.
 *
 * GPGME 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.
 *
 * GPGME 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 */

#include <config.h>
#ifndef HAVE_DOSISH_SYSTEM

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <signal.h>
#include <fcntl.h>
#include "syshdr.h"

#include "io.h"

#define DEBUG_SELECT_ENABLED 0

#if DEBUG_SELECT_ENABLED
# define DEBUG_SELECT(a) fprintf a
#else
# define DEBUG_SELECT(a) do { } while(0)
#endif


int
_gpgme_io_read ( int fd, void *buffer, size_t count )
{
    int nread;

    do {
        nread = read (fd, buffer, count);
    } while (nread == -1 && errno == EINTR );
    return nread;
}


int
_gpgme_io_write ( int fd, const void *buffer, size_t count )
{
    int nwritten;

    do {
        nwritten = write (fd, buffer, count);
    } while (nwritten == -1 && errno == EINTR );
    return nwritten;
}

int
_gpgme_io_pipe ( int filedes[2], int inherit_idx )
{
    /* we don't need inherit_idx in this implementation */
    return pipe ( filedes );
}

int
_gpgme_io_close ( int fd )
{
    if ( fd == -1 )
        return -1;
    return close (fd);
}

int
_gpgme_io_set_nonblocking ( int fd )
{
    int flags;

    flags = fcntl (fd, F_GETFL, 0);
    if (flags == -1)
        return -1;
    flags |= O_NONBLOCK;
    return fcntl (fd, F_SETFL, flags);
}


int
_gpgme_io_spawn ( const char *path, char **argv,
                  struct spawn_fd_item_s *fd_child_list,
                  struct spawn_fd_item_s *fd_parent_list )
{
    static volatile int fixed_signals;
    pid_t pid;
    int i;

    if ( !fixed_signals ) { 
        struct sigaction act;
        
        sigaction( SIGPIPE, NULL, &act );
        if( act.sa_handler == SIG_DFL ) {
            act.sa_handler = SIG_IGN;
            sigemptyset( &act.sa_mask );
            act.sa_flags = 0;
            sigaction( SIGPIPE, &act, NULL);
        }
        fixed_signals = 1;
        /* fixme: This is not really MT safe */
    }

    
    pid = fork ();
    if (pid == -1) 
        return -1;

    if ( !pid ) { /* child */
        int duped_stdin = 0;
        int duped_stderr = 0;

        /* first close all fds which will not be duped */
        for (i=0; fd_child_list[i].fd != -1; i++ ) {
            if (fd_child_list[i].dup_to == -1 )
                close (fd_child_list[i].fd);
        }
        /* and now dup and close the rest */
        for (i=0; fd_child_list[i].fd != -1; i++ ) {
            if (fd_child_list[i].dup_to != -1 ) {
                if ( dup2 (fd_child_list[i].fd,
                           fd_child_list[i].dup_to ) == -1 ) {
                    fprintf (stderr, "dup2 failed in child: %s\n",
                             strerror (errno));
                    _exit (8);
                }
                if ( fd_child_list[i].dup_to == 0 )
                    duped_stdin=1;
                if ( fd_child_list[i].dup_to == 2 )
                    duped_stderr=1;
                close (fd_child_list[i].fd);
            }
        }

        if( !duped_stdin || !duped_stderr ) {
            int fd = open ( "/dev/null", O_RDWR );
            if ( fd == -1 ) {
                fprintf (stderr,"can't open `/dev/null': %s\n",
                         strerror (errno) );
                _exit (8);
            }
            /* Make sure that the process has a connected stdin */
            if ( !duped_stdin ) {
                if ( dup2 ( fd, 0 ) == -1 ) {
                    fprintf (stderr,"dup2(/dev/null, 0) failed: %s\n",
                             strerror (errno) );
                    _exit (8);
                }
            }
            /* We normally don't want all the normal output */
            if ( !duped_stderr ) {
                if (!getenv ("GPGME_DEBUG") ) {
                    if ( dup2 ( fd, 2 ) == -1 ) {
                        fprintf (stderr,"dup2(dev/null, 2) failed: %s\n",
                                 strerror (errno) );
                        _exit (8);
                    }
                }
            }
            close (fd);
        }

        execv ( path, argv );
        /* Hmm: in that case we could write a special status code to the
         * status-pipe */
        fprintf (stderr,"exec of `%s' failed\n", path );
        _exit (8);
    } /* end child */
    
    /* .dup_to is not used in the parent list */
    for (i=0; fd_parent_list[i].fd != -1; i++ ) {
        close (fd_parent_list[i].fd);
    }

    return (int)pid;
}


int
_gpgme_io_waitpid ( int pid, int hang, int *r_status, int *r_signal )
{
    int status;

    *r_status = 0;
    *r_signal = 0;
    if ( waitpid ( pid, &status, hang? 0 : WNOHANG ) == pid ) {
        if ( WIFSIGNALED (status) ) {
            *r_status = 4; /* Need some value here */
            *r_signal = WTERMSIG (status);
        }
        else if ( WIFEXITED (status) ) {
            *r_status = WEXITSTATUS (status);
        }
        else {
            *r_status = 4; /* oops */
        }
        return 1;
    }
    return 0;
}


/*
 * Select on the list of fds.
 * Returns: -1 = error
 *           0 = timeout or nothing to select
 *          >0 = number of signaled fds
 */
int
_gpgme_io_select ( struct io_select_fd_s *fds, size_t nfds )
{
    static fd_set readfds;
    static fd_set writefds;
    int any, i, max_fd, n, count;
    struct timeval timeout = { 0, 50 }; /* Use a 50ms timeout */
    
    FD_ZERO ( &readfds );
    FD_ZERO ( &writefds );
    max_fd = 0;

    DEBUG_SELECT ((stderr, "gpgme:select on [ "));
    any = 0;
    for ( i=0; i < nfds; i++ ) {
        if ( fds[i].fd == -1 ) 
            continue;
        if ( fds[i].for_read ) {
            assert ( !FD_ISSET ( fds[i].fd, &readfds ) );
            FD_SET ( fds[i].fd, &readfds );
            if ( fds[i].fd > max_fd )
                max_fd = fds[i].fd;
            DEBUG_SELECT ((stderr, "r%d ", fds[i].fd ));
            any = 1;
        }
        else if ( fds[i].for_write ) {
            assert ( !FD_ISSET ( fds[i].fd, &writefds ) );
            FD_SET ( fds[i].fd, &writefds );
            if ( fds[i].fd > max_fd )
                max_fd = fds[i].fd;
            DEBUG_SELECT ((stderr, "w%d ", fds[i].fd ));
            any = 1;
        }
        fds[i].signaled = 0;
    }
    DEBUG_SELECT ((stderr, "]\n" ));
    if ( !any )
        return 0;

    do {
        count = select ( max_fd+1, &readfds, &writefds, NULL, &timeout );
    } while ( count < 0 && errno == EINTR);
    if ( count < 0 ) {
        fprintf (stderr, "_gpgme_io_select failed: %s\n", strerror (errno) );
        return -1; /* error */
    }

#if DEBUG_SELECT_ENABLED
    fprintf (stderr, "gpgme:select OK [ " );
    for (i=0; i <= max_fd; i++ ) {
        if (FD_ISSET (i, &readfds) )
            fprintf (stderr, "r%d ", i );
        if (FD_ISSET (i, &writefds) )
            fprintf (stderr, "w%d ", i );
    }
    fprintf (stderr, "]\n" );
#endif
    
    /* n is used to optimize it a little bit */
    for ( n=count, i=0; i < nfds && n ; i++ ) {
        if ( fds[i].fd == -1 ) 
            ;
        else if ( fds[i].for_read ) {
            if ( FD_ISSET ( fds[i].fd, &readfds ) ) {
                fds[i].signaled = 1;
                n--;
            }
        }
        else if ( fds[i].for_write ) {
            if ( FD_ISSET ( fds[i].fd, &writefds ) ) {
                fds[i].signaled = 1;
                n--;
            }
        }
    }
    return count;
}


#endif /*!HAVE_DOSISH_SYSTEM*/