1 /*

     2  * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 #undef  _LARGEFILE64_SOURCE

    27 #define _LARGEFILE64_SOURCE 1

    28 

    29 #include "jni.h"

    30 #include "jvm.h"

    31 #include "jvm_md.h"

    32 #include "jni_util.h"

    33 #include "io_util.h"

    34 

    35 /*

    36  * Platform-specific support for java.lang.Process

    37  */

    38 #include <assert.h>

    39 #include <stddef.h>

    40 #include <stdlib.h>

    41 #include <sys/types.h>

    42 #include <ctype.h>

    43 #include <sys/wait.h>

    44 #include <signal.h>

    45 #include <string.h>

    46 

    47 #if defined(__solaris__) || defined(_ALLBSD_SOURCE) || defined(_AIX)

    48 #include <spawn.h>

    49 #endif

    50 

    51 #include "childproc.h"

    52 

    53 /*

    54  * There are 4 possible strategies we might use to "fork":

    55  *

    56  * - fork(2).  Very portable and reliable but subject to

    57  *   failure due to overcommit (see the documentation on

    58  *   /proc/sys/vm/overcommit_memory in Linux proc(5)).

    59  *   This is the ancient problem of spurious failure whenever a large

    60  *   process starts a small subprocess.

    61  *

    62  * - vfork().  Using this is scary because all relevant man pages

    63  *   contain dire warnings, e.g. Linux vfork(2).  But at least it's

    64  *   documented in the glibc docs and is standardized by XPG4.

    65  *   http://www.opengroup.org/onlinepubs/000095399/functions/vfork.html

    66  *   On Linux, one might think that vfork() would be implemented using

    67  *   the clone system call with flag CLONE_VFORK, but in fact vfork is

    68  *   a separate system call (which is a good sign, suggesting that

    69  *   vfork will continue to be supported at least on Linux).

    70  *   Another good sign is that glibc implements posix_spawn using

    71  *   vfork whenever possible.  Note that we cannot use posix_spawn

    72  *   ourselves because there's no reliable way to close all inherited

    73  *   file descriptors.

    74  *

    75  * - clone() with flags CLONE_VM but not CLONE_THREAD.  clone() is

    76  *   Linux-specific, but this ought to work - at least the glibc

    77  *   sources contain code to handle different combinations of CLONE_VM

    78  *   and CLONE_THREAD.  However, when this was implemented, it

    79  *   appeared to fail on 32-bit i386 (but not 64-bit x86_64) Linux with

    80  *   the simple program

    81  *     Runtime.getRuntime().exec("/bin/true").waitFor();

    82  *   with:

    83  *     #  Internal Error (os_linux_x86.cpp:683), pid=19940, tid=2934639536

    84  *     #  Error: pthread_getattr_np failed with errno = 3 (ESRCH)

    85  *   We believe this is a glibc bug, reported here:

    86  *     http://sources.redhat.com/bugzilla/show_bug.cgi?id=10311

    87  *   but the glibc maintainers closed it as WONTFIX.

    88  *

    89  * - posix_spawn(). While posix_spawn() is a fairly elaborate and

    90  *   complicated system call, it can't quite do everything that the old

    91  *   fork()/exec() combination can do, so the only feasible way to do

    92  *   this, is to use posix_spawn to launch a new helper executable

    93  *   "jprochelper", which in turn execs the target (after cleaning

    94  *   up file-descriptors etc.) The end result is the same as before,

    95  *   a child process linked to the parent in the same way, but it

    96  *   avoids the problem of duplicating the parent (VM) process

    97  *   address space temporarily, before launching the target command.

    98  *

    99  * Based on the above analysis, we are currently using vfork() on

   100  * Linux and spawn() on other Unix systems, but the code to use clone()

   101  * and fork() remains.

   102  */

   103 

   104 

   105 static void

   106 setSIGCHLDHandler(JNIEnv *env)

   107 {

   108     /* There is a subtle difference between having the signal handler

   109      * for SIGCHLD be SIG_DFL and SIG_IGN.  We cannot obtain process

   110      * termination information for child processes if the signal

   111      * handler is SIG_IGN.  It must be SIG_DFL.

   112      *

   113      * We used to set the SIGCHLD handler only on Linux, but it's

   114      * safest to set it unconditionally.

   115      *

   116      * Consider what happens if java's parent process sets the SIGCHLD

   117      * handler to SIG_IGN.  Normally signal handlers are inherited by

   118      * children, but SIGCHLD is a controversial case.  Solaris appears

   119      * to always reset it to SIG_DFL, but this behavior may be

   120      * non-standard-compliant, and we shouldn't rely on it.

   121      *

   122      * References:

   123      * http://www.opengroup.org/onlinepubs/7908799/xsh/exec.html

   124      * http://www.pasc.org/interps/unofficial/db/p1003.1/pasc-1003.1-132.html

   125      */

   126     struct sigaction sa;

   127     sa.sa_handler = SIG_DFL;

   128     sigemptyset(&sa.sa_mask);

   129     sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;

   130     if (sigaction(SIGCHLD, &sa, NULL) < 0)

   131         JNU_ThrowInternalError(env, "Can't set SIGCHLD handler");

   132 }

   133 

   134 static void*

   135 xmalloc(JNIEnv *env, size_t size)

   136 {

   137     void *p = malloc(size);

   138     if (p == NULL)

   139         JNU_ThrowOutOfMemoryError(env, NULL);

   140     return p;

   141 }

   142 

   143 #define NEW(type, n) ((type *) xmalloc(env, (n) * sizeof(type)))

   144 

   145 /**

   146  * If PATH is not defined, the OS provides some default value.

   147  * Unfortunately, there's no portable way to get this value.

   148  * Fortunately, it's only needed if the child has PATH while we do not.

   149  */

   150 static const char*

   151 defaultPath(void)

   152 {

   153 #ifdef __solaris__

   154     /* These really are the Solaris defaults! */

   155     return (geteuid() == 0 || getuid() == 0) ?

   156         "/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin:/usr/sbin" :

   157         "/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin:";

   158 #else

   159     return ":/bin:/usr/bin";    /* glibc */

   160 #endif

   161 }

   162 

   163 static const char*

   164 effectivePath(void)

   165 {

   166     const char *s = getenv("PATH");

   167     return (s != NULL) ? s : defaultPath();

   168 }

   169 

   170 static int

   171 countOccurrences(const char *s, char c)

   172 {

   173     int count;

   174     for (count = 0; *s != '\0'; s++)

   175         count += (*s == c);

   176     return count;

   177 }

   178 

   179 static const char * const *

   180 effectivePathv(JNIEnv *env)

   181 {

   182     char *p;

   183     int i;

   184     const char *path = effectivePath();

   185     int count = countOccurrences(path, ':') + 1;

   186     size_t pathvsize = sizeof(const char *) * (count+1);

   187     size_t pathsize = strlen(path) + 1;

   188     const char **pathv = (const char **) xmalloc(env, pathvsize + pathsize);

   189 

   190     if (pathv == NULL)

   191         return NULL;

   192     p = (char *) pathv + pathvsize;

   193     memcpy(p, path, pathsize);

   194     /* split PATH by replacing ':' with NULs; empty components => "." */

   195     for (i = 0; i < count; i++) {

   196         char *q = p + strcspn(p, ":");

   197         pathv[i] = (p == q) ? "." : p;

   198         *q = '\0';

   199         p = q + 1;

   200     }

   201     pathv[count] = NULL;

   202     return pathv;

   203 }

   204 

   205 JNIEXPORT void JNICALL

   206 Java_java_lang_UNIXProcess_init(JNIEnv *env, jclass clazz)

   207 {

   208     parentPathv = effectivePathv(env);

   209     CHECK_NULL(parentPathv);

   210     setSIGCHLDHandler(env);

   211 }

   212 

   213 

   214 #ifndef WIFEXITED

   215 #define WIFEXITED(status) (((status)&0xFF) == 0)

   216 #endif

   217 

   218 #ifndef WEXITSTATUS

   219 #define WEXITSTATUS(status) (((status)>>8)&0xFF)

   220 #endif

   221 

   222 #ifndef WIFSIGNALED

   223 #define WIFSIGNALED(status) (((status)&0xFF) > 0 && ((status)&0xFF00) == 0)

   224 #endif

   225 

   226 #ifndef WTERMSIG

   227 #define WTERMSIG(status) ((status)&0x7F)

   228 #endif

   229 

   230 /* Block until a child process exits and return its exit code.

   231    Note, can only be called once for any given pid. */

   232 JNIEXPORT jint JNICALL

   233 Java_java_lang_UNIXProcess_waitForProcessExit(JNIEnv* env,

   234                                               jobject junk,

   235                                               jint pid)

   236 {

   237     /* We used to use waitid() on Solaris, waitpid() on Linux, but

   238      * waitpid() is more standard, so use it on all POSIX platforms. */

   239     int status;

   240     /* Wait for the child process to exit.  This returns immediately if

   241        the child has already exited. */

   242     while (waitpid(pid, &status, 0) < 0) {

   243         switch (errno) {

   244         case ECHILD: return 0;

   245         case EINTR: break;

   246         default: return -1;

   247         }

   248     }

   249 

   250     if (WIFEXITED(status)) {

   251         /*

   252          * The child exited normally; get its exit code.

   253          */

   254         return WEXITSTATUS(status);

   255     } else if (WIFSIGNALED(status)) {

   256         /* The child exited because of a signal.

   257          * The best value to return is 0x80 + signal number,

   258          * because that is what all Unix shells do, and because

   259          * it allows callers to distinguish between process exit and

   260          * process death by signal.

   261          * Unfortunately, the historical behavior on Solaris is to return

   262          * the signal number, and we preserve this for compatibility. */

   263 #ifdef __solaris__

   264         return WTERMSIG(status);

   265 #else

   266         return 0x80 + WTERMSIG(status);

   267 #endif

   268     } else {

   269         /*

   270          * Unknown exit code; pass it through.

   271          */

   272         return status;

   273     }

   274 }

   275 

   276 static const char *

   277 getBytes(JNIEnv *env, jbyteArray arr)

   278 {

   279     return arr == NULL ? NULL :

   280         (const char*) (*env)->GetByteArrayElements(env, arr, NULL);

   281 }

   282 

   283 static void

   284 releaseBytes(JNIEnv *env, jbyteArray arr, const char* parr)

   285 {

   286     if (parr != NULL)

   287         (*env)->ReleaseByteArrayElements(env, arr, (jbyte*) parr, JNI_ABORT);

   288 }

   289 

   290 static void

   291 throwIOException(JNIEnv *env, int errnum, const char *defaultDetail)

   292 {

   293     static const char * const format = "error=%d, %s";

   294     const char *detail = defaultDetail;

   295     char *errmsg;

   296     jstring s;

   297 

   298     if (errnum != 0) {

   299         const char *s = strerror(errnum);

   300         if (strcmp(s, "Unknown error") != 0)

   301             detail = s;

   302     }

   303     /* ASCII Decimal representation uses 2.4 times as many bits as binary. */

   304     errmsg = NEW(char, strlen(format) + strlen(detail) + 3 * sizeof(errnum));

   305     if (errmsg == NULL)

   306         return;

   307 

   308     sprintf(errmsg, format, errnum, detail);

   309     s = JNU_NewStringPlatform(env, errmsg);

   310     if (s != NULL) {

   311         jobject x = JNU_NewObjectByName(env, "java/io/IOException",

   312                                         "(Ljava/lang/String;)V", s);

   313         if (x != NULL)

   314             (*env)->Throw(env, x);

   315     }

   316     free(errmsg);

   317 }

   318 

   319 #ifdef DEBUG_PROCESS

   320 /* Debugging process code is difficult; where to write debug output? */

   321 static void

   322 debugPrint(char *format, ...)

   323 {

   324     FILE *tty = fopen("/dev/tty", "w");

   325     va_list ap;

   326     va_start(ap, format);

   327     vfprintf(tty, format, ap);

   328     va_end(ap);

   329     fclose(tty);

   330 }

   331 #endif /* DEBUG_PROCESS */

   332 

   333 static void

   334 copyPipe(int from[2], int to[2])

   335 {

   336     to[0] = from[0];

   337     to[1] = from[1];

   338 }

   339 

   340 /* arg is an array of pointers to 0 terminated strings. array is terminated

   341  * by a null element.

   342  *

   343  * *nelems and *nbytes receive the number of elements of array (incl 0)

   344  * and total number of bytes (incl. 0)

   345  * Note. An empty array will have one null element

   346  * But if arg is null, then *nelems set to 0, and *nbytes to 0

   347  */

   348 static void arraysize(const char * const *arg, int *nelems, int *nbytes)

   349 {

   350     int i, bytes, count;

   351     const char * const *a = arg;

   352     char *p;

   353     int *q;

   354     if (arg == 0) {

   355         *nelems = 0;

   356         *nbytes = 0;

   357         return;

   358     }

   359     /* count the array elements and number of bytes */

   360     for (count=0, bytes=0; *a != 0; count++, a++) {

   361         bytes += strlen(*a)+1;

   362     }

   363     *nbytes = bytes;

   364     *nelems = count+1;

   365 }

   366 

   367 /* copy the strings from arg[] into buf, starting at given offset

   368  * return new offset to next free byte

   369  */

   370 static int copystrings(char *buf, int offset, const char * const *arg) {

   371     char *p;

   372     const char * const *a;

   373     int count=0;

   374 

   375     if (arg == 0) {

   376         return offset;

   377     }

   378     for (p=buf+offset, a=arg; *a != 0; a++) {

   379         int len = strlen(*a) +1;

   380         memcpy(p, *a, len);

   381         p += len;

   382         count += len;

   383     }

   384     return offset+count;

   385 }

   386 

   387 /**

   388  * We are unusually paranoid; use of clone/vfork is

   389  * especially likely to tickle gcc/glibc bugs.

   390  */

   391 #ifdef __attribute_noinline__  /* See: sys/cdefs.h */

   392 __attribute_noinline__

   393 #endif

   394 

   395 #define START_CHILD_USE_CLONE 0  /* clone() currently disabled; see above. */

   396 

   397 #ifdef START_CHILD_USE_CLONE

   398 static pid_t

   399 cloneChild(ChildStuff *c) {

   400 #ifdef __linux__

   401 #define START_CHILD_CLONE_STACK_SIZE (64 * 1024)

   402     /*

   403      * See clone(2).

   404      * Instead of worrying about which direction the stack grows, just

   405      * allocate twice as much and start the stack in the middle.

   406      */

   407     if ((c->clone_stack = malloc(2 * START_CHILD_CLONE_STACK_SIZE)) == NULL)

   408         /* errno will be set to ENOMEM */

   409         return -1;

   410     return clone(childProcess,

   411                  c->clone_stack + START_CHILD_CLONE_STACK_SIZE,

   412                  CLONE_VFORK | CLONE_VM | SIGCHLD, c);

   413 #else

   414 /* not available on Solaris / Mac */

   415     assert(0);

   416     return -1;

   417 #endif

   418 }

   419 #endif

   420 

   421 static pid_t

   422 vforkChild(ChildStuff *c) {

   423     volatile pid_t resultPid;

   424 

   425     /*

   426      * We separate the call to vfork into a separate function to make

   427      * very sure to keep stack of child from corrupting stack of parent,

   428      * as suggested by the scary gcc warning:

   429      *  warning: variable 'foo' might be clobbered by 'longjmp' or 'vfork'

   430      */

   431     resultPid = vfork();

   432 

   433     if (resultPid == 0) {

   434         childProcess(c);

   435     }

   436     assert(resultPid != 0);  /* childProcess never returns */

   437     return resultPid;

   438 }

   439 

   440 static pid_t

   441 forkChild(ChildStuff *c) {

   442     pid_t resultPid;

   443 

   444     /*

   445      * From Solaris fork(2): In Solaris 10, a call to fork() is

   446      * identical to a call to fork1(); only the calling thread is

   447      * replicated in the child process. This is the POSIX-specified

   448      * behavior for fork().

   449      */

   450     resultPid = fork();

   451 

   452     if (resultPid == 0) {

   453         childProcess(c);

   454     }

   455     assert(resultPid != 0);  /* childProcess never returns */

   456     return resultPid;

   457 }

   458 

   459 #if defined(__solaris__) || defined(_ALLBSD_SOURCE) || defined(_AIX)

   460 static pid_t

   461 spawnChild(JNIEnv *env, jobject process, ChildStuff *c, const char *helperpath) {

   462     pid_t resultPid;

   463     jboolean isCopy;

   464     int i, offset, rval, bufsize, magic;

   465     char *buf, buf1[16];

   466     char *hlpargs[2];

   467     SpawnInfo sp;

   468 

   469     /* need to tell helper which fd is for receiving the childstuff

   470      * and which fd to send response back on

   471      */

   472     snprintf(buf1, sizeof(buf1), "%d:%d", c->childenv[0], c->fail[1]);

   473     /* put the fd string as argument to the helper cmd */

   474     hlpargs[0] = buf1;

   475     hlpargs[1] = 0;

   476 

   477     /* Following items are sent down the pipe to the helper

   478      * after it is spawned.

   479      * All strings are null terminated. All arrays of strings

   480      * have an empty string for termination.

   481      * - the ChildStuff struct

   482      * - the SpawnInfo struct

   483      * - the argv strings array

   484      * - the envv strings array

   485      * - the home directory string

   486      * - the parentPath string

   487      * - the parentPathv array

   488      */

   489     /* First calculate the sizes */

   490     arraysize(c->argv, &sp.nargv, &sp.argvBytes);

   491     bufsize = sp.argvBytes;

   492     arraysize(c->envv, &sp.nenvv, &sp.envvBytes);

   493     bufsize += sp.envvBytes;

   494     sp.dirlen = c->pdir == 0 ? 0 : strlen(c->pdir)+1;

   495     bufsize += sp.dirlen;

   496     arraysize(parentPathv, &sp.nparentPathv, &sp.parentPathvBytes);

   497     bufsize += sp.parentPathvBytes;

   498     /* We need to clear FD_CLOEXEC if set in the fds[].

   499      * Files are created FD_CLOEXEC in Java.

   500      * Otherwise, they will be closed when the target gets exec'd */

   501     for (i=0; i<3; i++) {

   502         if (c->fds[i] != -1) {

   503             int flags = fcntl(c->fds[i], F_GETFD);

   504             if (flags & FD_CLOEXEC) {

   505                 fcntl(c->fds[i], F_SETFD, flags & (~1));

   506             }

   507         }

   508     }

   509 

   510     rval = posix_spawn(&resultPid, helperpath, 0, 0, (char * const *) hlpargs, environ);

   511 

   512     if (rval != 0) {

   513         return -1;

   514     }

   515 

   516     /* now the lengths are known, copy the data */

   517     buf = NEW(char, bufsize);

   518     if (buf == 0) {

   519         return -1;

   520     }

   521     offset = copystrings(buf, 0, &c->argv[0]);

   522     offset = copystrings(buf, offset, &c->envv[0]);

   523     memcpy(buf+offset, c->pdir, sp.dirlen);

   524     offset += sp.dirlen;

   525     offset = copystrings(buf, offset, parentPathv);

   526     assert(offset == bufsize);

   527 

   528     magic = magicNumber();

   529 

   530     /* write the two structs and the data buffer */

   531     write(c->childenv[1], (char *)&magic, sizeof(magic)); // magic number first

   532     write(c->childenv[1], (char *)c, sizeof(*c));

   533     write(c->childenv[1], (char *)&sp, sizeof(sp));

   534     write(c->childenv[1], buf, bufsize);

   535     free(buf);

   536 

   537     /* In this mode an external main() in invoked which calls back into

   538      * childProcess() in this file, rather than directly

   539      * via the statement below */

   540     return resultPid;

   541 }

   542 #endif

   543 

   544 /*

   545  * Start a child process running function childProcess.

   546  * This function only returns in the parent.

   547  */

   548 static pid_t

   549 startChild(JNIEnv *env, jobject process, ChildStuff *c, const char *helperpath) {

   550     switch (c->mode) {

   551       case MODE_VFORK:

   552         return vforkChild(c);

   553       case MODE_FORK:

   554         return forkChild(c);

   555 #if defined(__solaris__) || defined(_ALLBSD_SOURCE) || defined(_AIX)

   556       case MODE_POSIX_SPAWN:

   557         return spawnChild(env, process, c, helperpath);

   558 #endif

   559       default:

   560         return -1;

   561     }

   562 }

   563 

   564 JNIEXPORT jint JNICALL

   565 Java_java_lang_UNIXProcess_forkAndExec(JNIEnv *env,

   566                                        jobject process,

   567                                        jint mode,

   568                                        jbyteArray helperpath,

   569                                        jbyteArray prog,

   570                                        jbyteArray argBlock, jint argc,

   571                                        jbyteArray envBlock, jint envc,

   572                                        jbyteArray dir,

   573                                        jintArray std_fds,

   574                                        jboolean redirectErrorStream)

   575 {

   576     int errnum;

   577     int resultPid = -1;

   578     int in[2], out[2], err[2], fail[2], childenv[2];

   579     jint *fds = NULL;

   580     const char *phelperpath = NULL;

   581     const char *pprog = NULL;

   582     const char *pargBlock = NULL;

   583     const char *penvBlock = NULL;

   584     ChildStuff *c;

   585 

   586     in[0] = in[1] = out[0] = out[1] = err[0] = err[1] = fail[0] = fail[1] = -1;

   587     childenv[0] = childenv[1] = -1;

   588 

   589     if ((c = NEW(ChildStuff, 1)) == NULL) return -1;

   590     c->argv = NULL;

   591     c->envv = NULL;

   592     c->pdir = NULL;

   593     c->clone_stack = NULL;

   594 

   595     /* Convert prog + argBlock into a char ** argv.

   596      * Add one word room for expansion of argv for use by

   597      * execve_as_traditional_shell_script.

   598      * This word is also used when using spawn mode

   599      */

   600     assert(prog != NULL && argBlock != NULL);

   601     if ((phelperpath = getBytes(env, helperpath))   == NULL) goto Catch;

   602     if ((pprog       = getBytes(env, prog))         == NULL) goto Catch;

   603     if ((pargBlock   = getBytes(env, argBlock))     == NULL) goto Catch;

   604     if ((c->argv     = NEW(const char *, argc + 3)) == NULL) goto Catch;

   605     c->argv[0] = pprog;

   606     c->argc = argc + 2;

   607     initVectorFromBlock(c->argv+1, pargBlock, argc);

   608 

   609     if (envBlock != NULL) {

   610         /* Convert envBlock into a char ** envv */

   611         if ((penvBlock = getBytes(env, envBlock))   == NULL) goto Catch;

   612         if ((c->envv = NEW(const char *, envc + 1)) == NULL) goto Catch;

   613         initVectorFromBlock(c->envv, penvBlock, envc);

   614     }

   615 

   616     if (dir != NULL) {

   617         if ((c->pdir = getBytes(env, dir)) == NULL) goto Catch;

   618     }

   619 

   620     assert(std_fds != NULL);

   621     fds = (*env)->GetIntArrayElements(env, std_fds, NULL);

   622     if (fds == NULL) goto Catch;

   623 

   624     if ((fds[0] == -1 && pipe(in)  < 0) ||

   625         (fds[1] == -1 && pipe(out) < 0) ||

   626         (fds[2] == -1 && pipe(err) < 0) ||

   627         (pipe(childenv) < 0) ||

   628         (pipe(fail) < 0)) {

   629         throwIOException(env, errno, "Bad file descriptor");

   630         goto Catch;

   631     }

   632     c->fds[0] = fds[0];

   633     c->fds[1] = fds[1];

   634     c->fds[2] = fds[2];

   635 

   636     copyPipe(in,   c->in);

   637     copyPipe(out,  c->out);

   638     copyPipe(err,  c->err);

   639     copyPipe(fail, c->fail);

   640     copyPipe(childenv, c->childenv);

   641 

   642     c->redirectErrorStream = redirectErrorStream;

   643     c->mode = mode;

   644 

   645     resultPid = startChild(env, process, c, phelperpath);

   646     assert(resultPid != 0);

   647 

   648     if (resultPid < 0) {

   649         switch (c->mode) {

   650           case MODE_VFORK:

   651             throwIOException(env, errno, "vfork failed");

   652             break;

   653           case MODE_FORK:

   654             throwIOException(env, errno, "fork failed");

   655             break;

   656           case MODE_POSIX_SPAWN:

   657             throwIOException(env, errno, "spawn failed");

   658             break;

   659         }

   660         goto Catch;

   661     }

   662     close(fail[1]); fail[1] = -1; /* See: WhyCantJohnnyExec  (childproc.c)  */

   663 

   664     switch (readFully(fail[0], &errnum, sizeof(errnum))) {

   665     case 0: break; /* Exec succeeded */

   666     case sizeof(errnum):

   667         waitpid(resultPid, NULL, 0);

   668         throwIOException(env, errnum, "Exec failed");

   669         goto Catch;

   670     default:

   671         throwIOException(env, errno, "Read failed");

   672         goto Catch;

   673     }

   674 

   675     fds[0] = (in [1] != -1) ? in [1] : -1;

   676     fds[1] = (out[0] != -1) ? out[0] : -1;

   677     fds[2] = (err[0] != -1) ? err[0] : -1;

   678 

   679  Finally:

   680     free(c->clone_stack);

   681 

   682     /* Always clean up the child's side of the pipes */

   683     closeSafely(in [0]);

   684     closeSafely(out[1]);

   685     closeSafely(err[1]);

   686 

   687     /* Always clean up fail and childEnv descriptors */

   688     closeSafely(fail[0]);

   689     closeSafely(fail[1]);

   690     closeSafely(childenv[0]);

   691     closeSafely(childenv[1]);

   692 

   693     releaseBytes(env, helperpath, phelperpath);

   694     releaseBytes(env, prog,       pprog);

   695     releaseBytes(env, argBlock,   pargBlock);

   696     releaseBytes(env, envBlock,   penvBlock);

   697     releaseBytes(env, dir,        c->pdir);

   698 

   699     free(c->argv);

   700     free(c->envv);

   701     free(c);

   702 

   703     if (fds != NULL)

   704         (*env)->ReleaseIntArrayElements(env, std_fds, fds, 0);

   705 

   706     return resultPid;

   707 

   708  Catch:

   709     /* Clean up the parent's side of the pipes in case of failure only */

   710     closeSafely(in [1]); in[1] = -1;

   711     closeSafely(out[0]); out[0] = -1;

   712     closeSafely(err[0]); err[0] = -1;

   713     goto Finally;

   714 }

   715 

   716 JNIEXPORT void JNICALL

   717 Java_java_lang_UNIXProcess_destroyProcess(JNIEnv *env,

   718                                           jobject junk,

   719                                           jint pid,

   720                                           jboolean force)

   721 {

   722     int sig = (force == JNI_TRUE) ? SIGKILL : SIGTERM;

   723     kill(pid, sig);

   724 }