J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * |
| 3 | * |
| 4 | * A simple launcher to launch a program as if it was launched by inetd. |
| 5 | */ |
| 6 | #include <stdio.h> |
| 7 | #include <stdlib.h> |
| 8 | #include <sys/types.h> |
| 9 | #include <sys/socket.h> |
| 10 | #include <unistd.h> |
| 11 | #include <dirent.h> |
| 12 | #include <sys/stat.h> |
| 13 | #include <fcntl.h> |
| 14 | #include <ctype.h> |
| 15 | |
| 16 | #include "jni.h" |
| 17 | |
| 18 | #include "Launcher.h" |
| 19 | |
| 20 | /* |
| 21 | * Throws the exception of the given class name and detail message |
| 22 | */ |
| 23 | static void ThrowException(JNIEnv *env, const char *name, const char *msg) { |
| 24 | jclass cls = (*env)->FindClass(env, name); |
| 25 | if (cls != NULL) { |
| 26 | (*env)->ThrowNew(env, cls, msg); |
| 27 | } |
| 28 | } |
| 29 | |
| 30 | /* |
| 31 | * Convert a jstring to an ISO 8859_1 encoded C string |
| 32 | */ |
| 33 | static char* getString8859_1Chars(JNIEnv *env, jstring jstr) { |
| 34 | int i; |
| 35 | char *result; |
| 36 | jint len = (*env)->GetStringLength(env, jstr); |
| 37 | const jchar *str = (*env)->GetStringCritical(env, jstr, 0); |
| 38 | if (str == 0) { |
| 39 | return NULL; |
| 40 | } |
| 41 | |
| 42 | result = (char*)malloc(len+1); |
| 43 | if (result == 0) { |
| 44 | (*env)->ReleaseStringCritical(env, jstr, str); |
| 45 | ThrowException(env, "java/lang/OutOfMemoryError", NULL); |
| 46 | return NULL; |
| 47 | } |
| 48 | |
| 49 | for (i=0; i<len; i++) { |
| 50 | jchar unicode = str[i]; |
| 51 | if (unicode <= 0x00ff) |
| 52 | result[i] = unicode; |
| 53 | else |
| 54 | result[i] = '?'; |
| 55 | } |
| 56 | |
| 57 | result[len] = 0; |
| 58 | (*env)->ReleaseStringCritical(env, jstr, str); |
| 59 | return result; |
| 60 | } |
| 61 | |
| 62 | |
| 63 | /* |
| 64 | * Class: Launcher |
| 65 | * Method: launch0 |
| 66 | * Signature: ([Ljava/lang/String;I)V |
| 67 | */ |
| 68 | JNIEXPORT void JNICALL Java_Launcher_launch0 |
| 69 | (JNIEnv *env, jclass cls, jobjectArray cmdarray, jint serviceFd) |
| 70 | { |
| 71 | pid_t pid; |
| 72 | DIR* dp; |
| 73 | struct dirent* dirp; |
| 74 | int thisFd; |
| 75 | char** cmdv; |
| 76 | int i, cmdlen; |
| 77 | |
| 78 | /* |
| 79 | * Argument 0 of the command array is the program name. |
| 80 | * Here we just extract the program name and any arguments into |
| 81 | * a command array suitable for use with execvp. |
| 82 | */ |
| 83 | cmdlen = (*env)->GetArrayLength(env, cmdarray); |
| 84 | if (cmdlen == 0) { |
| 85 | ThrowException(env, "java/lang/IllegalArgumentException", |
| 86 | "command array must at least include the program name"); |
| 87 | return; |
| 88 | } |
| 89 | cmdv = (char **)malloc((cmdlen + 1) * sizeof(char *)); |
| 90 | if (cmdv == NULL) { |
| 91 | ThrowException(env, "java/lang/OutOfMemoryError", NULL); |
| 92 | return; |
| 93 | } |
| 94 | |
| 95 | for (i=0; i<cmdlen; i++) { |
| 96 | jstring str = (*env)->GetObjectArrayElement(env, cmdarray, i); |
| 97 | cmdv[i] = (char *) getString8859_1Chars(env, str); |
| 98 | if (cmdv[i] == NULL) { |
| 99 | return; |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | /* |
| 104 | * Command array must have NULL as the last entry |
| 105 | */ |
| 106 | cmdv[cmdlen] = NULL; |
| 107 | |
| 108 | /* |
| 109 | * Launch the program. As this isn't a complete inetd or Runtime.exec |
| 110 | * implementation we don't have a reaper to pick up child exit status. |
| 111 | */ |
| 112 | #ifdef __solaris__ |
| 113 | pid = fork1(); |
| 114 | #else |
| 115 | pid = fork(); |
| 116 | #endif |
| 117 | if (pid != 0) { |
| 118 | if (pid < 0) { |
| 119 | ThrowException(env, "java/io/IOException", "fork failed"); |
| 120 | } |
| 121 | return; |
| 122 | } |
| 123 | |
| 124 | /* |
| 125 | * We need to close all file descriptors except for serviceFd. To |
| 126 | * get the list of open file descriptos we read through /proc/self/fd |
| 127 | * but to open this requires a file descriptor. We could use a specific |
| 128 | * file descriptor and fdopendir but Linux doesn't seem to support |
| 129 | * fdopendir. Instead we use opendir and make an assumption on the |
| 130 | * file descriptor that is used (by opening & closing a file). |
| 131 | */ |
| 132 | thisFd = open("/dev/null", O_RDONLY); |
| 133 | if (thisFd < 0) { |
| 134 | _exit(-1); |
| 135 | } |
| 136 | close(thisFd); |
| 137 | |
| 138 | if ((dp = opendir("/proc/self/fd")) == NULL) { |
| 139 | _exit(-1); |
| 140 | } |
| 141 | |
| 142 | while ((dirp = readdir(dp)) != NULL) { |
| 143 | if (isdigit(dirp->d_name[0])) { |
| 144 | int fd = strtol(dirp->d_name, NULL, 10); |
| 145 | if (fd != serviceFd && fd != thisFd) { |
| 146 | close(fd); |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | closedir(dp); |
| 151 | |
| 152 | /* |
| 153 | * At this point all file descriptors are closed except for |
| 154 | * serviceFd. We not dup 0,1,2 to this file descriptor and |
| 155 | * close serviceFd. This should leave us with only 0,1,2 |
| 156 | * open and all connected to the same socket. |
| 157 | */ |
| 158 | dup2(serviceFd, STDIN_FILENO); |
| 159 | dup2(serviceFd, STDOUT_FILENO); |
| 160 | dup2(serviceFd, STDERR_FILENO); |
| 161 | close(serviceFd); |
| 162 | |
| 163 | execvp(cmdv[0], cmdv); |
| 164 | _exit(-1); |
| 165 | } |