| /* |
| * 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" |
| |
| /* |
| * 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 <sys/wait.h> |
| #else |
| #include <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 |
| Java_java_lang_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 |
| Java_java_lang_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. */ |
| errmsg = NEW(char, strlen(format) + strlen(detail) + 3 * sizeof(errnum)); |
| sprintf(errmsg, 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 |
| Java_java_lang_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 |
| Java_java_lang_UNIXProcess_destroyProcess(JNIEnv *env, jobject junk, jint pid) |
| { |
| kill(pid, SIGTERM); |
| } |
