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+ GNU GENERAL PUBLIC LICENSE
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+
+ END OF TERMS AND CONDITIONS
+
+ How to Apply These Terms to Your New Programs
+
+ If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+ To do so, attach the following notices to the program. It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+ <one line to give the program's name and a brief idea of what it does.>
+ Copyright (C) <year> <name of author>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+ If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+ <program> Copyright (C) <year> <name of author>
+ This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+ This is free software, and you are welcome to redistribute it
+ under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License. Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+ You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+ The GNU General Public License does not permit incorporating your program
+into proprietary programs. If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library. If this is what you want to do, use the GNU Lesser General
+Public License instead of this License. But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
--- /dev/null
+/*
+ * Simple LD_PRELOAD wrapper to "convert" network sockets to UNIX sockets;
+ * works for clients and servers. See README for details.
+ *
+ * Copyright (C) 2013 Simon Ruderich
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/* Necessary for RTLD_NEXT. */
+#define _GNU_SOURCE
+
+#include <assert.h>
+#include <dlfcn.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/un.h>
+#include <unistd.h>
+
+
+/* CONSTANTS */
+
+#define LOG_LEVEL_ERROR 1
+#define LOG_LEVEL_WARNING 2
+#define LOG_LEVEL_DEBUG 3
+#define LOG_LEVEL_MASK LOG_LEVEL_DEBUG
+
+#define LOG_LEVEL_PERROR 42
+
+
+/* GLOBAL VARIABLES */
+
+struct list {
+ int unix_sockfd;
+
+ int orig_domain;
+ int orig_type;
+
+ struct list *next;
+};
+
+static struct list socket_list = {
+ .unix_sockfd = -1, /* must not match a valid sockfd */
+};
+
+
+/* LOG FUNCTIONS/MACROS */
+
+static int get_log_level(void);
+
+static void log_helper(int action, const char *file, int line, const char *format, va_list ap) {
+ int saved_errno = errno;
+
+ static int log_level;
+ if (!log_level) {
+ log_level = get_log_level();
+ }
+
+ int level = action & LOG_LEVEL_MASK;
+ if (level > log_level) {
+ return;
+ }
+
+ const char *prefix;
+ if (level == LOG_LEVEL_DEBUG) {
+ prefix = "DEBUG";
+ } else if (level == LOG_LEVEL_WARNING) {
+ prefix = "WARN ";
+ } else if (level == LOG_LEVEL_ERROR) {
+ prefix = "ERROR";
+ } else {
+ prefix = "UNKNOWN";
+ }
+
+ /* Prevent other threads from interrupting the printf()s. */
+ flockfile(stderr);
+
+ fprintf(stderr, "socket2unix [%s] ", prefix);
+ fprintf(stderr, "[%s:%3d] ", file, line);
+ vfprintf(stderr, format, ap);
+
+ if ((action & ~LOG_LEVEL_MASK) == LOG_LEVEL_PERROR) {
+ fprintf(stderr, ": ");
+
+ errno = saved_errno;
+ perror("");
+ }
+
+ funlockfile(stderr);
+
+ if (level == LOG_LEVEL_ERROR) {
+ fprintf(stderr, "Aborting.\n");
+ exit(EXIT_FAILURE);
+ }
+}
+
+static void log_(int level, const char *file, int line, const char *format, ...)
+ __attribute__((format(printf, 4, 5)));
+static void log_(int level, const char *file, int line, const char *format, ...) {
+ va_list ap;
+
+ va_start(ap, format);
+ log_helper(level, file, line, format, ap);
+ va_end(ap);
+}
+
+#define ERROR(...) \
+ log_(LOG_LEVEL_ERROR, __FILE__, __LINE__, __VA_ARGS__)
+#define WARN(...) \
+ log_(LOG_LEVEL_WARNING, __FILE__, __LINE__, __VA_ARGS__)
+#define DEBUG(...) \
+ log_(LOG_LEVEL_DEBUG, __FILE__, __LINE__, __VA_ARGS__)
+
+#define DIE(...) \
+ log_(LOG_LEVEL_ERROR | LOG_LEVEL_PERROR, __FILE__, __LINE__, __VA_ARGS__)
+
+
+/* LD_PRELOAD */
+
+/* Load the function name using dlsym() if necessary and store it in pointer.
+ * Terminate program on failure. */
+#define LOAD_FUNCTION(pointer, name) \
+ if ((pointer) == NULL) { \
+ char *error; \
+ dlerror(); /* Clear possibly existing error. */ \
+ \
+ *(void **) (&(pointer)) = dlsym(RTLD_NEXT, (name)); \
+ \
+ if ((error = dlerror()) != NULL) { \
+ ERROR("%s\n", error); \
+ } \
+ }
+
+
+/* OTHER FUNCTIONS */
+
+static struct list *find_sockfd(int sockfd) {
+ struct list *e;
+
+ if (sockfd == socket_list.unix_sockfd) {
+ return NULL;
+ }
+
+ for (e = &socket_list; e != NULL; e = e->next) {
+ if (e->unix_sockfd == sockfd) {
+ return e;
+ }
+ }
+ return NULL;
+}
+static struct list *remove_sockfd(int sockfd) {
+ struct list *e, *p;
+
+ if (sockfd == socket_list.unix_sockfd) {
+ return NULL;
+ }
+
+ for (e = &socket_list, p = NULL; e != NULL; p = e, e = e->next) {
+ if (e->unix_sockfd == sockfd) {
+ p->next = e->next;
+ return e;
+ }
+ }
+ return NULL;
+}
+
+static const char *get_socket_path(void) {
+ const char *path = getenv("SOCKET2UNIX_PATH");
+ if (!path) {
+ ERROR("SOCKET2UNIX_PATH environment variable not defined\n");
+ }
+ if (path[0] != '/') {
+ ERROR("SOCKET2UNIX_PATH '%s' must be an absolute path\n", path);
+ }
+ return path;
+}
+static int get_log_level(void) {
+ const char *level = getenv("SOCKET2UNIX_DEBUG");
+ if (!level) {
+ return LOG_LEVEL_WARNING;
+ }
+ int number = atoi(level);
+ if (number <= 0 || number > LOG_LEVEL_DEBUG) {
+ number = LOG_LEVEL_DEBUG;
+ }
+ return number;
+}
+
+static const char *af_to_name(int af) {
+ if (af == AF_UNIX) {
+ return "AF_UNIX";
+ } else if (af == AF_LOCAL) {
+ return "AF_LOCAL";
+ } else if (af == AF_INET) {
+ return "AF_INET";
+ } else if (af == AF_INET6) {
+ return "AF_INET6";
+ } else if (af == AF_IPX) {
+ return "AF_IPX";
+ } else if (af == AF_NETLINK) {
+ return "AF_NETLINK";
+ } else if (af == AF_X25) {
+ return "AF_X25";
+ } else if (af == AF_AX25) {
+ return "AF_AX25";
+ } else if (af == AF_ATMPVC) {
+ return "AF_ATMPVC";
+ } else if (af == AF_APPLETALK) {
+ return "AF_APPLETALK";
+ } else if (af == AF_PACKET) {
+ return "AF_PACKET";
+ } else {
+ return "AF_UNKNOWN";
+ }
+}
+static const char *sock_to_name(int sock) {
+ if (sock & SOCK_STREAM) {
+ return "SOCK_STREAM";
+ } else if (sock & SOCK_DGRAM) {
+ return "SOCK_DGRAM";
+ } else if (sock & SOCK_SEQPACKET) {
+ return "SOCK_SEQPACKET";
+ } else if (sock & SOCK_RAW) {
+ return "SOCK_RAW";
+ } else if (sock & SOCK_RDM) {
+ return "SOCK_RDM";
+ } else if (sock & SOCK_PACKET) {
+ return "SOCK_PACKET";
+ } else {
+ return "SOCK_UNKNOWN";
+ }
+}
+/* for getsockopt()/setsockopt(). */
+static const char *level_to_name(int level) {
+ if (level == SOL_SOCKET) {
+ return "SOL_SOCKET";
+ } else if (level == SOL_IP) {
+ return "SOL_IP";
+ } else if (level == SOL_IPV6) {
+ return "SOL_IPV6";
+ } else if (level == IPPROTO_TCP) {
+ return "IPPROTO_TCP";
+ } else if (level == IPPROTO_UDP) {
+ return "IPPROTO_UDP";
+ } else {
+ return "SOL_UNKNOWN";
+ }
+}
+
+
+static int set_sockaddr_un(struct sockaddr_un *sockaddr,
+ const struct sockaddr *addr, socklen_t addrlen) {
+ /* Just in case ... */
+ if ((addr->sa_family == AF_INET
+ && addrlen < sizeof(struct sockaddr_in))
+ || (addr->sa_family == AF_INET6
+ && addrlen < sizeof(struct sockaddr_in6))) {
+ WARN("invalid addrlen from program\n");
+ return -1;
+ }
+
+ const char *socket_path = get_socket_path();
+
+ /* The program may open multiple sockets, e.g. IPv4 and IPv6 and on
+ * multiple ports. Create unique paths. */
+ const char *af;
+ int port;
+ if (addr->sa_family == AF_INET) {
+ af = "v4";
+ port = ntohs(((struct sockaddr_in *)addr)->sin_port);
+ } else if (addr->sa_family == AF_INET6) {
+ af = "v6";
+ port = ntohs(((struct sockaddr_in6 *)addr)->sin6_port);
+ } else {
+ af = "unknown";
+ port = 0;
+ WARN("unknown sa_family '%s' (%d)\n",
+ af_to_name(addr->sa_family), addr->sa_family);
+ }
+
+ /* Initialize sockaddr_un. */
+ sockaddr->sun_family = AF_UNIX;
+ int written = snprintf(sockaddr->sun_path, sizeof(sockaddr->sun_path),
+ "%s-%s-%d", socket_path, af, port);
+ /* The maximum length is quite short, check it. */
+ if (written >= (int)sizeof(sockaddr->sun_path)) {
+ ERROR("path '%s-%s-%d' too long for UNIX socket",
+ socket_path, af, port);
+ }
+
+ return 0;
+}
+
+
+/* FUNCTIONS OVERWRITTEN BY LD_PRELOAD */
+
+int socket(int domain, int type, int protocol) {
+ static int (*real_socket)(int, int, int);
+ LOAD_FUNCTION(real_socket, "socket");
+
+ if (domain == AF_UNIX || domain == AF_LOCAL) {
+ return real_socket(domain, type, protocol);
+ }
+
+ DEBUG("socket(%s, %s, %d)\n",
+ af_to_name(domain), sock_to_name(type), protocol);
+
+ /* We must return the replacement socket in case the program uses select()
+ * or similar on it. */
+
+ int unix_sockfd = real_socket(AF_UNIX, type, 0);
+ if (unix_sockfd < 0) {
+ DIE("bind(): failed to create UNIX socket");
+ }
+
+ struct list *entry = malloc(sizeof(*entry));
+ if (!entry) {
+ DIE("socket(): malloc");
+ }
+ memset(entry, 0, sizeof(*entry));
+
+ entry->unix_sockfd = unix_sockfd;
+ entry->orig_domain = domain;
+ entry->orig_type = type;
+
+ entry->next = socket_list.next;
+ socket_list.next = entry;
+
+ return unix_sockfd;
+}
+
+int close(int fd) {
+ static int (*real_close)(int);
+ LOAD_FUNCTION(real_close, "close");
+
+ DEBUG("close(%d)\n", fd);
+
+ struct list *entry = remove_sockfd(fd);
+ if (entry == NULL) {
+ DEBUG("close(%d): sockfd not found\n", fd);
+ return real_close(fd);
+ }
+ assert(fd == entry->unix_sockfd);
+ free(entry);
+
+ return real_close(fd);
+}
+
+int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
+ static int (*real_bind)(int, const struct sockaddr *, socklen_t);
+ LOAD_FUNCTION(real_bind, "bind");
+
+ DEBUG("bind(%d, ..)\n", sockfd);
+
+ if (addr == NULL || addrlen < sizeof(addr->sa_family)
+ || addr->sa_family == AF_UNIX
+ || addr->sa_family == AF_LOCAL) {
+ return real_bind(sockfd, addr, addrlen);
+ }
+
+ struct list *entry = find_sockfd(sockfd);
+ if (!entry) {
+ DEBUG("bind(%d, ..): sockfd not found\n", sockfd);
+ return real_bind(sockfd, addr, addrlen);
+ }
+ assert(sockfd == entry->unix_sockfd);
+ DEBUG("bind(%d, ..): %s %s\n",
+ sockfd,
+ af_to_name(entry->orig_domain),
+ sock_to_name(entry->orig_type));
+
+ struct sockaddr_un sockaddr;
+ if (set_sockaddr_un(&sockaddr, addr, addrlen) != 0) {
+ ERROR("connect(%d, ..) failed\n", sockfd);
+ }
+
+ DEBUG("bind(%d, ..): using path '%s'\n", sockfd, sockaddr.sun_path);
+
+ int attempts = 0;
+ while (attempts < 10) {
+ if (real_bind(entry->unix_sockfd, (struct sockaddr *)&sockaddr,
+ sizeof(sockaddr)) == 0) {
+ /* Success. */
+ return 0;
+ }
+ if (errno != EADDRINUSE) {
+ DIE("bind(%d, ..): failed to bind to '%s'",
+ sockfd, sockaddr.sun_path);
+ }
+
+ /* File already exists, unlink it if it's a socket. This has a race
+ * condition, but the worst case is that we delete a file created by
+ * the user at the path he told us to use. Tough luck .. */
+
+ struct stat buf;
+ if (lstat(sockaddr.sun_path, &buf) != 0) {
+ /* Looks like a race, better abort. */
+ DIE("bind(%d, ..): lstat on UNIX socket '%s' failed",
+ sockfd, sockaddr.sun_path);
+ }
+
+ if (!S_ISSOCK(buf.st_mode)) {
+ ERROR("bind(%d, ..): path '%s' exits and is no socket\n",
+ sockfd, sockaddr.sun_path);
+ }
+
+ WARN("bind(%d, ..): unlinking '%s'\n", sockfd, sockaddr.sun_path);
+ if (unlink(sockaddr.sun_path) != 0) {
+ DIE("bind(%d, ..): unlink '%s' failed",
+ sockfd, sockaddr.sun_path);
+ }
+
+ attempts++;
+ }
+
+ ERROR("bind(%d, ..): failed to create UNIX socket file\n", sockfd);
+ return -1; /* never reached */
+}
+
+int listen(int sockfd, int backlog) {
+ static int (*real_listen)(int, int);
+ LOAD_FUNCTION(real_listen, "listen");
+
+ DEBUG("listen(%d, %d)\n", sockfd, backlog);
+
+ struct list *entry = find_sockfd(sockfd);
+ if (!entry) {
+ DEBUG("listen(%d, %d): sockfd not found\n", sockfd, backlog);
+ return real_listen(sockfd, backlog);
+ }
+ assert(sockfd == entry->unix_sockfd);
+ DEBUG("listen(%d, %d): %s %s\n",
+ sockfd, backlog,
+ af_to_name(entry->orig_domain),
+ sock_to_name(entry->orig_type));
+
+ if (real_listen(entry->unix_sockfd, backlog) != 0) {
+ DIE("listen(): failed to listen");
+ }
+
+ return 0;
+}
+
+int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen) {
+ static int (*real_accept)(int, struct sockaddr *, socklen_t *);
+ LOAD_FUNCTION(real_accept, "accept");
+
+ DEBUG("accept(%d, ..)\n", sockfd);
+
+ struct list *entry = find_sockfd(sockfd);
+ if (!entry) {
+ DEBUG("accept(%d, ..): sockfd not found\n", sockfd);
+ return real_accept(sockfd, addr, addrlen);
+ }
+ assert(sockfd == entry->unix_sockfd);
+ DEBUG("accept(%d, ..): %s %s\n",
+ sockfd,
+ af_to_name(entry->orig_domain),
+ sock_to_name(entry->orig_type));
+
+ struct sockaddr_un sockaddr;
+ socklen_t size = sizeof(sockaddr);
+ int sock = real_accept(entry->unix_sockfd, (struct sockaddr *)&sockaddr,
+ &size);
+ if (sock < 0) {
+ DIE("accept(%d, ..): failed to accept", sockfd);
+ }
+
+ if (addr == NULL || addrlen == NULL) {
+ return sock;
+ }
+ DEBUG("accept(%d, ..): caller requested sockaddr\n", sockfd);
+
+ if (*addrlen < size) {
+ WARN("accept(%d, ..): invalid addrlen from program", sockfd);
+ errno = EINVAL;
+ return -1;
+ }
+
+ /* This is not the protocol the program asked for (AF_* vs. AF_UNIX), but
+ * it should work most of the time. */
+ memcpy(addr, &sockaddr, size);
+ *addrlen = size;
+
+ /* TODO: is this enough? */
+
+ return sock;
+}
+
+int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen) {
+ static int (*real_connect)(int, const struct sockaddr *, socklen_t);
+ LOAD_FUNCTION(real_connect, "connect");
+
+ DEBUG("connect(%d, ..)\n", sockfd);
+
+ if (addr == NULL || addrlen < sizeof(addr->sa_family)
+ || addr->sa_family == AF_UNIX
+ || addr->sa_family == AF_LOCAL) {
+ return real_connect(sockfd, addr, addrlen);
+ }
+
+ struct list *entry = find_sockfd(sockfd);
+ if (!entry) {
+ DEBUG("connect(%d, ..): sockfd not found\n", sockfd);
+ return real_connect(sockfd, addr, addrlen);
+ }
+ assert(sockfd == entry->unix_sockfd);
+ DEBUG("connect(%d, ..): %s %s\n",
+ sockfd,
+ af_to_name(entry->orig_domain),
+ sock_to_name(entry->orig_type));
+
+ struct sockaddr_un sockaddr;
+ if (set_sockaddr_un(&sockaddr, addr, addrlen) != 0) {
+ ERROR("connect(%d, ..) failed\n", sockfd);
+ }
+
+ DEBUG("connect(%d, ..): using path '%s'\n", sockfd, sockaddr.sun_path);
+
+ if (real_connect(entry->unix_sockfd, (struct sockaddr *)&sockaddr,
+ sizeof(sockaddr)) != 0) {
+ DIE("connect(%d, ..): failed to connect", sockfd);
+ }
+
+ return 0;
+}
+
+
+int getsockname(int sockfd, struct sockaddr *addr, socklen_t *addrlen) {
+ static int (*real_getsockname)(int, struct sockaddr *, socklen_t *);
+ LOAD_FUNCTION(real_getsockname, "getsockname");
+
+ DEBUG("getsockname(%d, ..)\n", sockfd);
+
+ return real_getsockname(sockfd, addr, addrlen);
+}
+
+int getpeername(int sockfd, struct sockaddr *addr, socklen_t *addrlen) {
+ static int (*real_getpeername)(int, struct sockaddr *, socklen_t *);
+ LOAD_FUNCTION(real_getpeername, "getpeername");
+
+ DEBUG("getpeername(%d, ..)\n", sockfd);
+
+ return real_getpeername(sockfd, addr, addrlen);
+}
+
+int getsockopt(int sockfd, int level, int optname, void *optval, socklen_t *optlen) {
+ static int (*real_getsockopt)(int, int, int, void *, socklen_t *);
+ LOAD_FUNCTION(real_getsockopt, "getsockopt");
+
+ DEBUG("getsockopt(%d, %d %s, %d, ..)\n",
+ sockfd,
+ level, level_to_name(level),
+ optname);
+
+ return real_getsockopt(sockfd, level, optname, optval, optlen);
+}
+int setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t optlen) {
+ static int (*real_setsockopt)(int, int, int, const void *, socklen_t);
+ LOAD_FUNCTION(real_setsockopt, "setsockopt");
+
+ DEBUG("setsockopt(%d, %d %s, %d, ..)\n",
+ sockfd,
+ level, level_to_name(level),
+ optname);
+
+ return real_setsockopt(sockfd, level, optname, optval, optlen);
+}
ruderich.org/simon / socket2unix / socket2unix.git / commitdiff