uxproces.c

Netscape NSPR库源码

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is the Netscape Portable Runtime (NSPR).
 * 
 * The Initial Developer of the Original Code is Netscape
 * Communications Corporation.  Portions created by Netscape are 
 * Copyright (C) 1998-2000 Netscape Communications Corporation.  All
 * Rights Reserved.
 * 
 * Contributor(s):
 * 
 * Alternatively, the contents of this file may be used under the
 * terms of the GNU General Public License Version 2 or later (the
 * "GPL"), in which case the provisions of the GPL are applicable 
 * instead of those above.  If you wish to allow use of your 
 * version of this file only under the terms of the GPL and not to
 * allow others to use your version of this file under the MPL,
 * indicate your decision by deleting the provisions above and
 * replace them with the notice and other provisions required by
 * the GPL.  If you do not delete the provisions above, a recipient
 * may use your version of this file under either the MPL or the
 * GPL.
 */

#include "primpl.h"

#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <signal.h>
#include <sys/wait.h>
#if defined(AIX)
#include <dlfcn.h>  /* For dlopen, dlsym, dlclose */
#endif

#if defined(DARWIN)
#include <crt_externs.h>
#else
extern char **environ;
#endif

/*
 * HP-UX 9 doesn't have the SA_RESTART flag.
 */
#ifndef SA_RESTART
#define SA_RESTART 0
#endif

#if defined(VMS)
static PRLock *_pr_vms_fork_lock = NULL;
#endif

/*
 **********************************************************************
 *
 * The Unix process routines
 *
 **********************************************************************
 */

#define _PR_SIGNALED_EXITSTATUS 256

typedef enum pr_PidState {
    _PR_PID_DETACHED,
    _PR_PID_REAPED,
    _PR_PID_WAITING
} pr_PidState;

typedef struct pr_PidRecord {
    pid_t pid;
    int exitStatus;
    pr_PidState state;
    PRCondVar *reapedCV;
    struct pr_PidRecord *next;
} pr_PidRecord;

/*
 * Irix sprocs and LinuxThreads are actually a kind of processes
 * that can share the virtual address space and file descriptors.
 */
#if (defined(IRIX) && !defined(_PR_PTHREADS)) \
        || (defined(LINUX) && defined(_PR_PTHREADS))
#define _PR_SHARE_CLONES
#endif

/*
 * The macro _PR_NATIVE_THREADS indicates that we are
 * using native threads only, so waitpid() blocks just the
 * calling thread, not the process.  In this case, the waitpid
 * daemon thread can safely block in waitpid().  So we don't
 * need to catch SIGCHLD, and the pipe to unblock PR_Poll() is
 * also not necessary.
 */

#if defined(_PR_GLOBAL_THREADS_ONLY) \
	|| (defined(_PR_PTHREADS) && !defined(LINUX))
#define _PR_NATIVE_THREADS
#endif

/*
 * All the static variables used by the Unix process routines are
 * collected in this structure.
 */

static struct {
    PRCallOnceType once;
    PRThread *thread;
    PRLock *ml;
#if defined(_PR_NATIVE_THREADS)
    PRInt32 numProcs;
    PRCondVar *cv;
#else
    int pipefd[2];
#endif
    pr_PidRecord **pidTable;

#ifdef _PR_SHARE_CLONES
    struct pr_CreateProcOp *opHead, *opTail;
#endif

#ifdef AIX
    pid_t (*forkptr)(void);  /* Newer versions of AIX (starting in 4.3.2)
                              * have f_fork, which is faster than the
                              * regular fork in a multithreaded process
                              * because it skips calling the fork handlers.
                              * So we look up the f_fork symbol to see if
                              * it's available and fall back on fork.
                              */
#endif /* AIX */
} pr_wp;

#ifdef _PR_SHARE_CLONES
static int pr_waitpid_daemon_exit;

void
_MD_unix_terminate_waitpid_daemon(void)
{
    if (pr_wp.thread) {
        pr_waitpid_daemon_exit = 1;
        write(pr_wp.pipefd[1], "", 1);
        PR_JoinThread(pr_wp.thread);
    }
}
#endif

static PRStatus _MD_InitProcesses(void);
#if !defined(_PR_NATIVE_THREADS)
static void pr_InstallSigchldHandler(void);
#endif

static PRProcess *
ForkAndExec(
    const char *path,
    char *const *argv,
    char *const *envp,
    const PRProcessAttr *attr)
{
    PRProcess *process;
    int nEnv, idx;
    char *const *childEnvp;
    char **newEnvp = NULL;
    int flags;
#ifdef VMS
    char VMScurdir[FILENAME_MAX+1] = { '\0' } ;
#endif	

    process = PR_NEW(PRProcess);
    if (!process) {
        PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
        return NULL;
    }

    childEnvp = envp;
    if (attr && attr->fdInheritBuffer) {
        if (NULL == childEnvp) {
#ifdef DARWIN
            childEnvp = *(_NSGetEnviron());
#else
            childEnvp = environ;
#endif
        }
        for (nEnv = 0; childEnvp[nEnv]; nEnv++) {
        }
        newEnvp = (char **) PR_MALLOC((nEnv + 2) * sizeof(char *));
        if (NULL == newEnvp) {
            PR_DELETE(process);
            PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
            return NULL;
        }
        for (idx = 0; idx < nEnv; idx++) {
            newEnvp[idx] = childEnvp[idx];
        }
        newEnvp[idx++] = attr->fdInheritBuffer;
        newEnvp[idx] = NULL;
        childEnvp = newEnvp;
    }

#ifdef VMS
/*
** Since vfork/exec is implemented VERY differently on OpenVMS, we have to
** handle the setting up of the standard streams very differently. And since
** none of this code can ever execute in the context of the child, we have
** to perform the chdir in the parent so the child is born into the correct
** directory (and then switch the parent back again).
*/
{
    int decc$set_child_standard_streams(int,int,int);
    int n, fd_stdin=0, fd_stdout=1, fd_stderr=2;

    /* Set up any standard streams we are given, assuming defaults */
    if (attr) {
       if (attr->stdinFd)
           fd_stdin = attr->stdinFd->secret->md.osfd;
       if (attr->stdoutFd)
           fd_stdout = attr->stdoutFd->secret->md.osfd;
       if (attr->stderrFd)
           fd_stderr = attr->stderrFd->secret->md.osfd;
    }

    /*
    ** Put a lock around anything that isn't going to be thread-safe.
    */
    PR_Lock(_pr_vms_fork_lock);

    /*
    ** Prepare the child's streams. We always do this in case a previous fork
    ** has left the stream assignments in some non-standard way.
    */
    n = decc$set_child_standard_streams(fd_stdin,fd_stdout,fd_stderr);
    if (n == -1) {
       PR_SetError(PR_BAD_DESCRIPTOR_ERROR, errno);
       PR_DELETE(process);
       if (newEnvp) {
           PR_DELETE(newEnvp);
       }
       PR_Unlock(_pr_vms_fork_lock);
       return NULL;
    }

    /* Switch directory if we have to */
    if (attr) {
       if (attr->currentDirectory) {
           if ( (getcwd(VMScurdir,sizeof(VMScurdir)) == NULL) ||
                (chdir(attr->currentDirectory) < 0) ) {
               PR_SetError(PR_DIRECTORY_OPEN_ERROR, errno);
               PR_DELETE(process);
               if (newEnvp) {
                   PR_DELETE(newEnvp);
               }
               PR_Unlock(_pr_vms_fork_lock);
               return NULL;
           }
       }
    }
}
#endif /* VMS */

#ifdef AIX
    process->md.pid = (*pr_wp.forkptr)();
#elif defined(NTO)
    /*
     * fork() & exec() does not work in a multithreaded process.
     * Use spawn() instead.
     */
    {
        int fd_map[3] = { 0, 1, 2 };

        if (attr) {
            if (attr->stdinFd && attr->stdinFd->secret->md.osfd != 0) {
                fd_map[0] = dup(attr->stdinFd->secret->md.osfd);
                flags = fcntl(fd_map[0], F_GETFL, 0);
                if (flags & O_NONBLOCK)
                    fcntl(fd_map[0], F_SETFL, flags & ~O_NONBLOCK);
            }
            if (attr->stdoutFd && attr->stdoutFd->secret->md.osfd != 1) {
                fd_map[1] = dup(attr->stdoutFd->secret->md.osfd);
                flags = fcntl(fd_map[1], F_GETFL, 0);
                if (flags & O_NONBLOCK)
                    fcntl(fd_map[1], F_SETFL, flags & ~O_NONBLOCK);
            }
            if (attr->stderrFd && attr->stderrFd->secret->md.osfd != 2) {
                fd_map[2] = dup(attr->stderrFd->secret->md.osfd);
                flags = fcntl(fd_map[2], F_GETFL, 0);
                if (flags & O_NONBLOCK)
                    fcntl(fd_map[2], F_SETFL, flags & ~O_NONBLOCK);
            }

            PR_ASSERT(attr->currentDirectory == NULL);  /* not implemented */
        }

        process->md.pid = spawn(path, 3, fd_map, NULL, argv, childEnvp);

        if (fd_map[0] != 0)
            close(fd_map[0]);
        if (fd_map[1] != 1)
            close(fd_map[1]);
        if (fd_map[2] != 2)
            close(fd_map[2]);
    }
#else
    process->md.pid = fork();
#endif
    if ((pid_t) -1 == process->md.pid) {
        PR_SetError(PR_INSUFFICIENT_RESOURCES_ERROR, errno);
        PR_DELETE(process);
        if (newEnvp) {
            PR_DELETE(newEnvp);
        }
        return NULL;
    } else if (0 == process->md.pid) {  /* the child process */
        /*
         * If the child process needs to exit, it must call _exit().
         * Do not call exit(), because exit() will flush and close
         * the standard I/O file descriptors, and hence corrupt
         * the parent process's standard I/O data structures.
         */

#if !defined(NTO)
#ifdef VMS
       /* OpenVMS has already handled all this above */
#else
        if (attr) {
            /* the osfd's to redirect stdin, stdout, and stderr to */
            int in_osfd = -1, out_osfd = -1, err_osfd = -1;

            if (attr->stdinFd
                    && attr->stdinFd->secret->md.osfd != 0) {
                in_osfd = attr->stdinFd->secret->md.osfd;
                if (dup2(in_osfd, 0) != 0) {
                    _exit(1);  /* failed */
                }
                flags = fcntl(0, F_GETFL, 0);
                if (flags & O_NONBLOCK) {
                    fcntl(0, F_SETFL, flags & ~O_NONBLOCK);
                }
            }
            if (attr->stdoutFd
                    && attr->stdoutFd->secret->md.osfd != 1) {
                out_osfd = attr->stdoutFd->secret->md.osfd;
                if (dup2(out_osfd, 1) != 1) {
                    _exit(1);  /* failed */
                }
                flags = fcntl(1, F_GETFL, 0);
                if (flags & O_NONBLOCK) {
                    fcntl(1, F_SETFL, flags & ~O_NONBLOCK);
                }
            }
            if (attr->stderrFd
                    && attr->stderrFd->secret->md.osfd != 2) {
                err_osfd = attr->stderrFd->secret->md.osfd;
                if (dup2(err_osfd, 2) != 2) {
                    _exit(1);  /* failed */
                }
                flags = fcntl(2, F_GETFL, 0);
                if (flags & O_NONBLOCK) {
                    fcntl(2, F_SETFL, flags & ~O_NONBLOCK);
                }
            }
            if (in_osfd != -1) {
                close(in_osfd);
            }
            if (out_osfd != -1 && out_osfd != in_osfd) {
                close(out_osfd);
            }
            if (err_osfd != -1 && err_osfd != in_osfd
                    && err_osfd != out_osfd) {
                close(err_osfd);
            }
            if (attr->currentDirectory) {
                if (chdir(attr->currentDirectory) < 0) {
                    _exit(1);  /* failed */
                }
            }
        }
#endif /* !VMS */

        if (childEnvp) {
            (void)execve(path, argv, childEnvp);
        } else {
            /* Inherit the environment of the parent. */
            (void)execv(path, argv);
        }
        /* Whoops! It returned. That's a bad sign. */
#ifdef VMS
       /*
       ** On OpenVMS we are still in the context of the parent, and so we
       ** can (and should!) perform normal error handling.
       */
       PR_SetError(PR_UNKNOWN_ERROR, errno);
       PR_DELETE(process);
       if (newEnvp) {
           PR_DELETE(newEnvp);
       }
       if (VMScurdir[0] != '\0')
           chdir(VMScurdir);
       PR_Unlock(_pr_vms_fork_lock);
       return NULL;
#else
        _exit(1);
#endif /* VMS */
#endif /* !NTO */
    }

    if (newEnvp) {
        PR_DELETE(newEnvp);
    }
#ifdef VMS
    /* If we switched directories, then remember to switch back */
    if (VMScurdir[0] != '\0') {
       chdir(VMScurdir); /* can't do much if it fails */
    }
    PR_Unlock(_pr_vms_fork_lock);
#endif /* VMS */

#if defined(_PR_NATIVE_THREADS)
    PR_Lock(pr_wp.ml);
    if (0 == pr_wp.numProcs++) {
        PR_NotifyCondVar(pr_wp.cv);
    }
    PR_Unlock(pr_wp.ml);
#endif
    return process;
}

#ifdef _PR_SHARE_CLONES

struct pr_CreateProcOp {
    const char *path;
    char *const *argv;
    char *const *envp;
    const PRProcessAttr *attr;
    PRProcess *process;
    PRErrorCode prerror;
    PRInt32 oserror;
    PRBool done;
    PRCondVar *doneCV;
    struct pr_CreateProcOp *next;
};

PRProcess *
_MD_CreateUnixProcess(
    const char *path,
    char *const *argv,
    char *const *envp,
    const PRProcessAttr *attr)
{
    struct pr_CreateProcOp *op;
    PRProcess *proc;
    int rv;

    if (PR_CallOnce(&pr_wp.once, _MD_InitProcesses) == PR_FAILURE) {
	return NULL;
    }

    op = PR_NEW(struct pr_CreateProcOp);
    if (NULL == op) {
	PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
	return NULL;
    }
    op->path = path;
    op->argv = argv;
    op->envp = envp;
    op->attr = attr;
    op->done = PR_FALSE;
    op->doneCV = PR_NewCondVar(pr_wp.ml);
    if (NULL == op->doneCV) {
	PR_DELETE(op);
	return NULL;
    }
    PR_Lock(pr_wp.ml);

    /* add to the tail of op queue */
    op->next = NULL;
    if (pr_wp.opTail) {
	pr_wp.opTail->next = op;
	pr_wp.opTail = op;
    } else {
	PR_ASSERT(NULL == pr_wp.opHead);
	pr_wp.opHead = pr_wp.opTail = op;
    }

    /* wake up the daemon thread */
    do {
        rv = write(pr_wp.pipefd[1], "", 1);