/*
* Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
#undef _LARGEFILE64_SOURCE
#define _LARGEFILE64_SOURCE 1
#include "jni.h"
#include "jvm.h"
#include "jvm_md.h"
#include "jni_util.h"
#include "io_util.h"
#include "JNIHelp.h"
#define NATIVE_METHOD(className, functionName, signature) \
{ #functionName, signature, (void*)(className ## _ ## functionName) }
/*
* Platform-specific support for java.lang.Process
*/
#include <assert.h>
#include <stddef.h>
#include <stdlib.h>
#include <sys/types.h>
#include <ctype.h>
#ifdef _ALLBSD_SOURCE
#include <wait.h>
#else
#include <sys/wait.h>
#endif
#include <signal.h>
#include <string.h>
#include <errno.h>
#include <dirent.h>
#include <unistd.h>
#include <fcntl.h>
#include <limits.h>
#ifdef __APPLE__
#include <crt_externs.h>
#define environ (*_NSGetEnviron())
#endif
/*
* There are 3 possible strategies we might use to "fork":
*
* - fork(2). Very portable and reliable but subject to
* failure due to overcommit (see the documentation on
* /proc/sys/vm/overcommit_memory in Linux proc(5)).
* This is the ancient problem of spurious failure whenever a large
* process starts a small subprocess.
*
* - vfork(). Using this is scary because all relevant man pages
* contain dire warnings, e.g. Linux vfork(2). But at least it's
* documented in the glibc docs and is standardized by XPG4.
* http://www.opengroup.org/onlinepubs/000095399/functions/vfork.html
* On Linux, one might think that vfork() would be implemented using
* the clone system call with flag CLONE_VFORK, but in fact vfork is
* a separate system call (which is a good sign, suggesting that
* vfork will continue to be supported at least on Linux).
* Another good sign is that glibc implements posix_spawn using
* vfork whenever possible. Note that we cannot use posix_spawn
* ourselves because there's no reliable way to close all inherited
* file descriptors.
*
* - clone() with flags CLONE_VM but not CLONE_THREAD. clone() is
* Linux-specific, but this ought to work - at least the glibc
* sources contain code to handle different combinations of CLONE_VM
* and CLONE_THREAD. However, when this was implemented, it
* appeared to fail on 32-bit i386 (but not 64-bit x86_64) Linux with
* the simple program
* Runtime.getRuntime().exec("/bin/true").waitFor();
* with:
* # Internal Error (os_linux_x86.cpp:683), pid=19940, tid=2934639536
* # Error: pthread_getattr_np failed with errno = 3 (ESRCH)
* We believe this is a glibc bug, reported here:
* http://sources.redhat.com/bugzilla/show_bug.cgi?id=10311
* but the glibc maintainers closed it as WONTFIX.
*
* Based on the above analysis, we are currently using vfork() on
* Linux and fork() on other Unix systems, but the code to use clone()
* remains.
*/
#define START_CHILD_USE_CLONE 0 /* clone() currently disabled; see above. */
#ifndef START_CHILD_USE_CLONE
#ifdef __linux__
#define START_CHILD_USE_CLONE 1
#else
#define START_CHILD_USE_CLONE 0
#endif
#endif
/* By default, use vfork() on Linux. */
#ifndef START_CHILD_USE_VFORK
#ifdef __linux__
#define START_CHILD_USE_VFORK 1
#else
#define START_CHILD_USE_VFORK 0
#endif
#endif
#if START_CHILD_USE_CLONE
#include <sched.h>
#define START_CHILD_SYSTEM_CALL "clone"
#elif START_CHILD_USE_VFORK
#define START_CHILD_SYSTEM_CALL "vfork"
#else
#define START_CHILD_SYSTEM_CALL "fork"
#endif
#ifndef STDIN_FILENO
#define STDIN_FILENO 0
#endif
#ifndef STDOUT_FILENO
#define STDOUT_FILENO 1
#endif
#ifndef STDERR_FILENO
#define STDERR_FILENO 2
#endif
#ifndef SA_NOCLDSTOP
#define SA_NOCLDSTOP 0
#endif
#ifndef SA_RESTART
#define SA_RESTART 0
#endif
#define FAIL_FILENO (STDERR_FILENO + 1)
/* TODO: Refactor. */
#define RESTARTABLE(_cmd, _result) do { \
do { \
_result = _cmd; \
} while((_result == -1) && (errno == EINTR)); \
} while(0)
/* This is one of the rare times it's more portable to declare an
* external symbol explicitly, rather than via a system header.
* The declaration is standardized as part of UNIX98, but there is
* no standard (not even de-facto) header file where the
* declaration is to be found. See:
* http://www.opengroup.org/onlinepubs/009695399/functions/environ.html
* http://www.opengroup.org/onlinepubs/009695399/functions/xsh_chap02_02.html
*
* "All identifiers in this volume of IEEE Std 1003.1-2001, except
* environ, are defined in at least one of the headers" (!)
*/
extern char **environ;
static void
setSIGCHLDHandler(JNIEnv *env)
{
/* There is a subtle difference between having the signal handler
* for SIGCHLD be SIG_DFL and SIG_IGN. We cannot obtain process
* termination information for child processes if the signal
* handler is SIG_IGN. It must be SIG_DFL.
*
* We used to set the SIGCHLD handler only on Linux, but it's
* safest to set it unconditionally.
*
* Consider what happens if java's parent process sets the SIGCHLD
* handler to SIG_IGN. Normally signal handlers are inherited by
* children, but SIGCHLD is a controversial case. Solaris appears
* to always reset it to SIG_DFL, but this behavior may be
* non-standard-compliant, and we shouldn't rely on it.
*
* References:
* http://www.opengroup.org/onlinepubs/7908799/xsh/exec.html
* http://www.pasc.org/interps/unofficial/db/p1003.1/pasc-1003.1-132.html
*/
struct sigaction sa;
sa.sa_handler = SIG_DFL;
sigemptyset(&sa.sa_mask);
sa.sa_flags = SA_NOCLDSTOP | SA_RESTART;
if (sigaction(SIGCHLD, &sa, NULL) < 0)
JNU_ThrowInternalError(env, "Can't set SIGCHLD handler");
}
static void*
xmalloc(JNIEnv *env, size_t size)
{
void *p = malloc(size);
if (p == NULL)
JNU_ThrowOutOfMemoryError(env, NULL);
return p;
}
#define NEW(type, n) ((type *) xmalloc(env, (n) * sizeof(type)))
/**
* If PATH is not defined, the OS provides some default value.
* Unfortunately, there's no portable way to get this value.
* Fortunately, it's only needed if the child has PATH while we do not.
*/
static const char*
defaultPath(void)
{
#ifdef __solaris__
/* These really are the Solaris defaults! */
return (geteuid() == 0 || getuid() == 0) ?
"/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin:/usr/sbin" :
"/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin:";
#else
return ":/bin:/usr/bin"; /* glibc */
#endif
}
static const char*
effectivePath(void)
{
const char *s = getenv("PATH");
return (s != NULL) ? s : defaultPath();
}
static int
countOccurrences(const char *s, char c)
{
int count;
for (count = 0; *s != '\0'; s++)
count += (*s == c);
return count;
}
static const char * const *
splitPath(JNIEnv *env, const char *path)
{
const char *p, *q;
char **pathv;
int i;
int count = countOccurrences(path, ':') + 1;
pathv = NEW(char*, count+1);
pathv[count] = NULL;
for (p = path, i = 0; i < count; i++, p = q + 1) {
for (q = p; (*q != ':') && (*q != '\0'); q++)
;
if (q == p) /* empty PATH component => "." */
pathv[i] = "./";
else {
int addSlash = ((*(q - 1)) != '/');
pathv[i] = NEW(char, q - p + addSlash + 1);
memcpy(pathv[i], p, q - p);
if (addSlash)
pathv[i][q - p] = '/';
pathv[i][q - p + addSlash] = '\0';
}
}
return (const char * const *) pathv;
}
/**
* Cached value of JVM's effective PATH.
* (We don't support putenv("PATH=...") in native code)
*/
static const char *parentPath;
/**
* Split, canonicalized version of parentPath
*/
static const char * const *parentPathv;
static jfieldID field_exitcode;
JNIEXPORT void JNICALL
UNIXProcess_initIDs(JNIEnv *env, jclass clazz)
{
field_exitcode = (*env)->GetFieldID(env, clazz, "exitcode", "I");
parentPath = effectivePath();
parentPathv = splitPath(env, parentPath);
setSIGCHLDHandler(env);
}
#ifndef WIFEXITED
#define WIFEXITED(status) (((status)&0xFF) == 0)
#endif
#ifndef WEXITSTATUS
#define WEXITSTATUS(status) (((status)>>8)&0xFF)
#endif
#ifndef WIFSIGNALED
#define WIFSIGNALED(status) (((status)&0xFF) > 0 && ((status)&0xFF00) == 0)
#endif
#ifndef WTERMSIG
#define WTERMSIG(status) ((status)&0x7F)
#endif
/* Block until a child process exits and return its exit code.
Note, can only be called once for any given pid. */
JNIEXPORT jint JNICALL
UNIXProcess_waitForProcessExit(JNIEnv* env,
jobject junk,
jint pid)
{
/* We used to use waitid() on Solaris, waitpid() on Linux, but
* waitpid() is more standard, so use it on all POSIX platforms. */
int status;
/* Wait for the child process to exit. This returns immediately if
the child has already exited. */
while (waitpid(pid, &status, 0) < 0) {
switch (errno) {
case ECHILD: return 0;
case EINTR: break;
default: return -1;
}
}
if (WIFEXITED(status)) {
/*
* The child exited normally; get its exit code.
*/
return WEXITSTATUS(status);
} else if (WIFSIGNALED(status)) {
/* The child exited because of a signal.
* The best value to return is 0x80 + signal number,
* because that is what all Unix shells do, and because
* it allows callers to distinguish between process exit and
* process death by signal.
* Unfortunately, the historical behavior on Solaris is to return
* the signal number, and we preserve this for compatibility. */
#ifdef __solaris__
return WTERMSIG(status);
#else
return 0x80 + WTERMSIG(status);
#endif
} else {
/*
* Unknown exit code; pass it through.
*/
return status;
}
}
static ssize_t
restartableWrite(int fd, const void *buf, size_t count)
{
ssize_t result;
RESTARTABLE(write(fd, buf, count), result);
return result;
}
static int
restartableDup2(int fd_from, int fd_to)
{
int err;
RESTARTABLE(dup2(fd_from, fd_to), err);
return err;
}
static int
restartableClose(int fd)
{
int err;
RESTARTABLE(close(fd), err);
return err;
}
static int
closeSafely(int fd)
{
return (fd == -1) ? 0 : restartableClose(fd);
}
static int
isAsciiDigit(char c)
{
return c >= '0' && c <= '9';
}
#ifdef _ALLBSD_SOURCE
#define FD_DIR "/dev/fd"
#define dirent64 dirent
#define readdir64 readdir
#else
#define FD_DIR "/proc/self/fd"
#endif
static int
closeDescriptors(void)
{
DIR *dp;
struct dirent64 *dirp;
int from_fd = FAIL_FILENO + 1;
/* We're trying to close all file descriptors, but opendir() might
* itself be implemented using a file descriptor, and we certainly
* don't want to close that while it's in use. We assume that if
* opendir() is implemented using a file descriptor, then it uses
* the lowest numbered file descriptor, just like open(). So we
* close a couple explicitly. */
restartableClose(from_fd); /* for possible use by opendir() */
restartableClose(from_fd + 1); /* another one for good luck */
if ((dp = opendir(FD_DIR)) == NULL)
return 0;
/* We use readdir64 instead of readdir to work around Solaris bug
* 6395699: /proc/self/fd fails to report file descriptors >= 1024 on Solaris 9
*/
while ((dirp = readdir64(dp)) != NULL) {
int fd;
if (isAsciiDigit(dirp->d_name[0]) &&
(fd = strtol(dirp->d_name, NULL, 10)) >= from_fd + 2)
restartableClose(fd);
}
closedir(dp);
return 1;
}
static int
moveDescriptor(int fd_from, int fd_to)
{
if (fd_from != fd_to) {
if ((restartableDup2(fd_from, fd_to) == -1) ||
(restartableClose(fd_from) == -1))
return -1;
}
return 0;
}
static const char *
getBytes(JNIEnv *env, jbyteArray arr)
{
return arr == NULL ? NULL :
(const char*) (*env)->GetByteArrayElements(env, arr, NULL);
}
static void
releaseBytes(JNIEnv *env, jbyteArray arr, const char* parr)
{
if (parr != NULL)
(*env)->ReleaseByteArrayElements(env, arr, (jbyte*) parr, JNI_ABORT);
}
static void
initVectorFromBlock(const char**vector, const char* block, int count)
{
int i;
const char *p;
for (i = 0, p = block; i < count; i++) {
/* Invariant: p always points to the start of a C string. */
vector[i] = p;
while (*(p++));
}
vector[count] = NULL;
}
static void
throwIOException(JNIEnv *env, int errnum, const char *defaultDetail)
{
static const char * const format = "error=%d, %s";
const char *detail = defaultDetail;
char *errmsg;
jstring s;
if (errnum != 0) {
const char *s = strerror(errnum);
if (strcmp(s, "Unknown error") != 0)
detail = s;
}
/* ASCII Decimal representation uses 2.4 times as many bits as binary. */
size_t newsize = strlen(format) + strlen(detail) + 3 * sizeof(errnum);
errmsg = NEW(char, newsize);
snprintf(errmsg, newsize, format, errnum, detail);
s = JNU_NewStringPlatform(env, errmsg);
if (s != NULL) {
jobject x = JNU_NewObjectByName(env, "java/io/IOException",
"(Ljava/lang/String;)V", s);
if (x != NULL)
(*env)->Throw(env, x);
}
free(errmsg);
}
#ifdef DEBUG_PROCESS
/* Debugging process code is difficult; where to write debug output? */
static void
debugPrint(char *format, ...)
{
FILE *tty = fopen("/dev/tty", "w");
va_list ap;
va_start(ap, format);
vfprintf(tty, format, ap);
va_end(ap);
fclose(tty);
}
#endif /* DEBUG_PROCESS */
/**
* Exec FILE as a traditional Bourne shell script (i.e. one without #!).
* If we could do it over again, we would probably not support such an ancient
* misfeature, but compatibility wins over sanity. The original support for
* this was imported accidentally from execvp().
*/
static void
execve_as_traditional_shell_script(const char *file,
const char *argv[],
const char *const envp[])
{
/* Use the extra word of space provided for us in argv by caller. */
const char *argv0 = argv[0];
const char *const *end = argv;
while (*end != NULL)
++end;
memmove(argv+2, argv+1, (end-argv) * sizeof (*end));
argv[0] = "/bin/sh";
argv[1] = file;
execve(argv[0], (char **) argv, (char **) envp);
/* Can't even exec /bin/sh? Big trouble, but let's soldier on... */
memmove(argv+1, argv+2, (end-argv) * sizeof (*end));
argv[0] = argv0;
}
/**
* Like execve(2), except that in case of ENOEXEC, FILE is assumed to
* be a shell script and the system default shell is invoked to run it.
*/
static void
execve_with_shell_fallback(const char *file,
const char *argv[],
const char *const envp[])
{
#if START_CHILD_USE_CLONE || START_CHILD_USE_VFORK
/* shared address space; be very careful. */
execve(file, (char **) argv, (char **) envp);
if (errno == ENOEXEC)
execve_as_traditional_shell_script(file, argv, envp);
#else
/* unshared address space; we can mutate environ. */
environ = (char **) envp;
execvp(file, (char **) argv);
#endif
}
/**
* 'execvpe' should have been included in the Unix standards,
* and is a GNU extension in glibc 2.10.
*
* JDK_execvpe is identical to execvp, except that the child environment is
* specified via the 3rd argument instead of being inherited from environ.
*/
static void
JDK_execvpe(const char *file,
const char *argv[],
const char *const envp[])
{
if (envp == NULL || (char **) envp == environ) {
execvp(file, (char **) argv);
return;
}
if (*file == '\0') {
errno = ENOENT;
return;
}
if (strchr(file, '/') != NULL) {
execve_with_shell_fallback(file, argv, envp);
} else {
/* We must search PATH (parent's, not child's) */
char expanded_file[PATH_MAX];
int filelen = strlen(file);
int sticky_errno = 0;
const char * const * dirs;
for (dirs = parentPathv; *dirs; dirs++) {
const char * dir = *dirs;
int dirlen = strlen(dir);
if (filelen + dirlen + 1 >= PATH_MAX) {
errno = ENAMETOOLONG;
continue;
}
memcpy(expanded_file, dir, dirlen);
memcpy(expanded_file + dirlen, file, filelen);
expanded_file[dirlen + filelen] = '\0';
execve_with_shell_fallback(expanded_file, argv, envp);
/* There are 3 responses to various classes of errno:
* return immediately, continue (especially for ENOENT),
* or continue with "sticky" errno.
*
* From exec(3):
*
* If permission is denied for a file (the attempted
* execve returned EACCES), these functions will continue
* searching the rest of the search path. If no other
* file is found, however, they will return with the
* global variable errno set to EACCES.
*/
switch (errno) {
case EACCES:
sticky_errno = errno;
/* FALLTHRU */
case ENOENT:
case ENOTDIR:
#ifdef ELOOP
case ELOOP:
#endif
#ifdef ESTALE
case ESTALE:
#endif
#ifdef ENODEV
case ENODEV:
#endif
#ifdef ETIMEDOUT
case ETIMEDOUT:
#endif
break; /* Try other directories in PATH */
default:
return;
}
}
if (sticky_errno != 0)
errno = sticky_errno;
}
}
/*
* Reads nbyte bytes from file descriptor fd into buf,
* The read operation is retried in case of EINTR or partial reads.
*
* Returns number of bytes read (normally nbyte, but may be less in
* case of EOF). In case of read errors, returns -1 and sets errno.
*/
static ssize_t
readFully(int fd, void *buf, size_t nbyte)
{
ssize_t remaining = nbyte;
for (;;) {
ssize_t n = read(fd, buf, remaining);
if (n == 0) {
return nbyte - remaining;
} else if (n > 0) {
remaining -= n;
if (remaining <= 0)
return nbyte;
/* We were interrupted in the middle of reading the bytes.
* Unlikely, but possible. */
buf = (void *) (((char *)buf) + n);
} else if (errno == EINTR) {
/* Strange signals like SIGJVM1 are possible at any time.
* See http://www.dreamsongs.com/WorseIsBetter.html */
} else {
return -1;
}
}
}
typedef struct _ChildStuff
{
int in[2];
int out[2];
int err[2];
int fail[2];
int fds[3];
const char **argv;
const char **envv;
const char *pdir;
jboolean redirectErrorStream;
#if START_CHILD_USE_CLONE
void *clone_stack;
#endif
} ChildStuff;
static void
copyPipe(int from[2], int to[2])
{
to[0] = from[0];
to[1] = from[1];
}
/**
* Child process after a successful fork() or clone().
* This function must not return, and must be prepared for either all
* of its address space to be shared with its parent, or to be a copy.
* It must not modify global variables such as "environ".
*/
static int
childProcess(void *arg)
{
const ChildStuff* p = (const ChildStuff*) arg;
/* Close the parent sides of the pipes.
Closing pipe fds here is redundant, since closeDescriptors()
would do it anyways, but a little paranoia is a good thing. */
if ((closeSafely(p->in[1]) == -1) ||
(closeSafely(p->out[0]) == -1) ||
(closeSafely(p->err[0]) == -1) ||
(closeSafely(p->fail[0]) == -1))
goto WhyCantJohnnyExec;
/* Give the child sides of the pipes the right fileno's. */
/* Note: it is possible for in[0] == 0 */
if ((moveDescriptor(p->in[0] != -1 ? p->in[0] : p->fds[0],
STDIN_FILENO) == -1) ||
(moveDescriptor(p->out[1]!= -1 ? p->out[1] : p->fds[1],
STDOUT_FILENO) == -1))
goto WhyCantJohnnyExec;
if (p->redirectErrorStream) {
if ((closeSafely(p->err[1]) == -1) ||
(restartableDup2(STDOUT_FILENO, STDERR_FILENO) == -1))
goto WhyCantJohnnyExec;
} else {
if (moveDescriptor(p->err[1] != -1 ? p->err[1] : p->fds[2],
STDERR_FILENO) == -1)
goto WhyCantJohnnyExec;
}
if (moveDescriptor(p->fail[1], FAIL_FILENO) == -1)
goto WhyCantJohnnyExec;
/* close everything */
if (closeDescriptors() == 0) { /* failed, close the old way */
int max_fd = (int)sysconf(_SC_OPEN_MAX);
int fd;
for (fd = FAIL_FILENO + 1; fd < max_fd; fd++)
if (restartableClose(fd) == -1 && errno != EBADF)
goto WhyCantJohnnyExec;
}
/* change to the new working directory */
if (p->pdir != NULL && chdir(p->pdir) < 0)
goto WhyCantJohnnyExec;
if (fcntl(FAIL_FILENO, F_SETFD, FD_CLOEXEC) == -1)
goto WhyCantJohnnyExec;
JDK_execvpe(p->argv[0], p->argv, p->envv);
WhyCantJohnnyExec:
/* We used to go to an awful lot of trouble to predict whether the
* child would fail, but there is no reliable way to predict the
* success of an operation without *trying* it, and there's no way
* to try a chdir or exec in the parent. Instead, all we need is a
* way to communicate any failure back to the parent. Easy; we just
* send the errno back to the parent over a pipe in case of failure.
* The tricky thing is, how do we communicate the *success* of exec?
* We use FD_CLOEXEC together with the fact that a read() on a pipe
* yields EOF when the write ends (we have two of them!) are closed.
*/
{
int errnum = errno;
restartableWrite(FAIL_FILENO, &errnum, sizeof(errnum));
}
restartableClose(FAIL_FILENO);
_exit(-1);
return 0; /* Suppress warning "no return value from function" */
}
/**
* Start a child process running function childProcess.
* This function only returns in the parent.
* We are unusually paranoid; use of clone/vfork is
* especially likely to tickle gcc/glibc bugs.
*/
#ifdef __attribute_noinline__ /* See: sys/cdefs.h */
__attribute_noinline__
#endif
static pid_t
startChild(ChildStuff *c) {
#if START_CHILD_USE_CLONE
#define START_CHILD_CLONE_STACK_SIZE (64 * 1024)
/*
* See clone(2).
* Instead of worrying about which direction the stack grows, just
* allocate twice as much and start the stack in the middle.
*/
if ((c->clone_stack = malloc(2 * START_CHILD_CLONE_STACK_SIZE)) == NULL)
/* errno will be set to ENOMEM */
return -1;
return clone(childProcess,
c->clone_stack + START_CHILD_CLONE_STACK_SIZE,
CLONE_VFORK | CLONE_VM | SIGCHLD, c);
#else
#if START_CHILD_USE_VFORK
/*
* We separate the call to vfork into a separate function to make
* very sure to keep stack of child from corrupting stack of parent,
* as suggested by the scary gcc warning:
* warning: variable 'foo' might be clobbered by 'longjmp' or 'vfork'
*/
volatile pid_t resultPid = vfork();
#else
/*
* From Solaris fork(2): In Solaris 10, a call to fork() is
* identical to a call to fork1(); only the calling thread is
* replicated in the child process. This is the POSIX-specified
* behavior for fork().
*/
pid_t resultPid = fork();
#endif
if (resultPid == 0)
childProcess(c);
assert(resultPid != 0); /* childProcess never returns */
return resultPid;
#endif /* ! START_CHILD_USE_CLONE */
}
JNIEXPORT jint JNICALL
UNIXProcess_forkAndExec(JNIEnv *env,
jobject process,
jbyteArray prog,
jbyteArray argBlock, jint argc,
jbyteArray envBlock, jint envc,
jbyteArray dir,
jintArray std_fds,
jboolean redirectErrorStream)
{
int errnum;
int resultPid = -1;
int in[2], out[2], err[2], fail[2];
jint *fds = NULL;
const char *pprog = NULL;
const char *pargBlock = NULL;
const char *penvBlock = NULL;
ChildStuff *c;
in[0] = in[1] = out[0] = out[1] = err[0] = err[1] = fail[0] = fail[1] = -1;
if ((c = NEW(ChildStuff, 1)) == NULL) return -1;
c->argv = NULL;
c->envv = NULL;
c->pdir = NULL;
#if START_CHILD_USE_CLONE
c->clone_stack = NULL;
#endif
/* Convert prog + argBlock into a char ** argv.
* Add one word room for expansion of argv for use by
* execve_as_traditional_shell_script.
*/
assert(prog != NULL && argBlock != NULL);
if ((pprog = getBytes(env, prog)) == NULL) goto Catch;
if ((pargBlock = getBytes(env, argBlock)) == NULL) goto Catch;
if ((c->argv = NEW(const char *, argc + 3)) == NULL) goto Catch;
c->argv[0] = pprog;
initVectorFromBlock(c->argv+1, pargBlock, argc);
if (envBlock != NULL) {
/* Convert envBlock into a char ** envv */
if ((penvBlock = getBytes(env, envBlock)) == NULL) goto Catch;
if ((c->envv = NEW(const char *, envc + 1)) == NULL) goto Catch;
initVectorFromBlock(c->envv, penvBlock, envc);
}
if (dir != NULL) {
if ((c->pdir = getBytes(env, dir)) == NULL) goto Catch;
}
assert(std_fds != NULL);
fds = (*env)->GetIntArrayElements(env, std_fds, NULL);
if (fds == NULL) goto Catch;
if ((fds[0] == -1 && pipe(in) < 0) ||
(fds[1] == -1 && pipe(out) < 0) ||
(fds[2] == -1 && pipe(err) < 0) ||
(pipe(fail) < 0)) {
throwIOException(env, errno, "Bad file descriptor");
goto Catch;
}
c->fds[0] = fds[0];
c->fds[1] = fds[1];
c->fds[2] = fds[2];
copyPipe(in, c->in);
copyPipe(out, c->out);
copyPipe(err, c->err);
copyPipe(fail, c->fail);
c->redirectErrorStream = redirectErrorStream;
resultPid = startChild(c);
assert(resultPid != 0);
if (resultPid < 0) {
throwIOException(env, errno, START_CHILD_SYSTEM_CALL " failed");
goto Catch;
}
restartableClose(fail[1]); fail[1] = -1; /* See: WhyCantJohnnyExec */
switch (readFully(fail[0], &errnum, sizeof(errnum))) {
case 0: break; /* Exec succeeded */
case sizeof(errnum):
waitpid(resultPid, NULL, 0);
throwIOException(env, errnum, "Exec failed");
goto Catch;
default:
throwIOException(env, errno, "Read failed");
goto Catch;
}
fds[0] = (in [1] != -1) ? in [1] : -1;
fds[1] = (out[0] != -1) ? out[0] : -1;
fds[2] = (err[0] != -1) ? err[0] : -1;
Finally:
#if START_CHILD_USE_CLONE
free(c->clone_stack);
#endif
/* Always clean up the child's side of the pipes */
closeSafely(in [0]);
closeSafely(out[1]);
closeSafely(err[1]);
/* Always clean up fail descriptors */
closeSafely(fail[0]);
closeSafely(fail[1]);
releaseBytes(env, prog, pprog);
releaseBytes(env, argBlock, pargBlock);
releaseBytes(env, envBlock, penvBlock);
releaseBytes(env, dir, c->pdir);
free(c->argv);
free(c->envv);
free(c);
if (fds != NULL)
(*env)->ReleaseIntArrayElements(env, std_fds, fds, 0);
return resultPid;
Catch:
/* Clean up the parent's side of the pipes in case of failure only */
closeSafely(in [1]);
closeSafely(out[0]);
closeSafely(err[0]);
goto Finally;
}
JNIEXPORT void JNICALL
UNIXProcess_destroyProcess(JNIEnv *env, jobject junk, jint pid)
{
kill(pid, SIGTERM);
}
static JNINativeMethod gMethods[] = {
NATIVE_METHOD(UNIXProcess, destroyProcess, "(I)V"),
NATIVE_METHOD(UNIXProcess, forkAndExec, "([B[BI[BI[B[IZ)I"),
NATIVE_METHOD(UNIXProcess, waitForProcessExit, "(I)I"),
NATIVE_METHOD(UNIXProcess, initIDs, "()V"),
};
void register_java_lang_UNIXProcess(JNIEnv* env) {
jniRegisterNativeMethods(env, "java/lang/UNIXProcess", gMethods, NELEM(gMethods));
}