jdk/src/solaris/native/java/lang/childproc.c
changeset 19399 e2e5122cd62e
child 22597 7515a991bb37
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/solaris/native/java/lang/childproc.c	Tue Aug 13 19:10:54 2013 +0100
@@ -0,0 +1,376 @@
+/*
+ * Copyright (c) 2013, 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.
+ */
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <limits.h>
+
+#include "childproc.h"
+
+
+ssize_t
+restartableWrite(int fd, const void *buf, size_t count)
+{
+    ssize_t result;
+    RESTARTABLE(write(fd, buf, count), result);
+    return result;
+}
+
+int
+restartableDup2(int fd_from, int fd_to)
+{
+    int err;
+    RESTARTABLE(dup2(fd_from, fd_to), err);
+    return err;
+}
+
+int
+closeSafely(int fd)
+{
+    return (fd == -1) ? 0 : close(fd);
+}
+
+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
+
+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.  */
+
+    close(from_fd);          /* for possible use by opendir() */
+    close(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)
+            close(fd);
+    }
+
+    closedir(dp);
+
+    return 1;
+}
+
+int
+moveDescriptor(int fd_from, int fd_to)
+{
+    if (fd_from != fd_to) {
+        if ((restartableDup2(fd_from, fd_to) == -1) ||
+            (close(fd_from) == -1))
+            return -1;
+    }
+    return 0;
+}
+
+int
+magicNumber() {
+    return 43110;
+}
+
+/*
+ * 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.
+ */
+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;
+        }
+    }
+}
+
+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;
+}
+
+/**
+ * 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().
+ */
+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.
+ */
+void
+execve_with_shell_fallback(int mode, const char *file,
+                           const char *argv[],
+                           const char *const envp[])
+{
+    if (mode == MODE_CLONE || mode == MODE_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);
+    }
+}
+
+/**
+ * '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.
+ */
+void
+JDK_execvpe(int mode, 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(mode, 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 + 2 >= PATH_MAX) {
+                errno = ENAMETOOLONG;
+                continue;
+            }
+            memcpy(expanded_file, dir, dirlen);
+            if (expanded_file[dirlen - 1] != '/')
+                expanded_file[dirlen++] = '/';
+            memcpy(expanded_file + dirlen, file, filelen);
+            expanded_file[dirlen + filelen] = '\0';
+            execve_with_shell_fallback(mode, 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;
+    }
+}
+
+/**
+ * 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".
+ */
+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->childenv[0])  == -1) ||
+        (closeSafely(p->childenv[1])  == -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 (close(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->mode, 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));
+    }
+    close(FAIL_FILENO);
+    _exit(-1);
+    return 0;  /* Suppress warning "no return value from function" */
+}