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lib.c
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lib.c
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#include "common.c"
static void getProfileName(char *p, size_t size)
{
readlink("/proc/self/exe", p, size);
char *end = p + size;
// Remove leading '/', replace remaining '/' to '\'
for (; *p && p<end; p++)
p[0] = p[1] == '/' ? '\\' : p[1];
}
#include <sys/un.h>
#include <pthread.h>
#include <sys/resource.h>
#include <sys/wait.h>
#include <errno.h>
#define NEXT(handle, path, func) ({ \
static typeof(&func) pfunc = NULL; \
if (!pfunc) \
pfunc = (typeof(&func))dlsym(RTLD_NEXT, #func); \
if (!pfunc) { \
if (!handle) { \
handle = dlopen(path, RTLD_LAZY); \
} \
if (!handle) { \
needConfig(); \
log_error("Ack, dlopen of '%s' failed: %s\n", \
path, dlerror()); \
} \
pfunc = (typeof(&func))dlsym(handle, #func); \
} \
if (!pfunc) { \
needConfig(); \
log_error("Ack, dlsym of '%s' (from '%s') failed: %s\n", \
#func, path, dlerror()); \
} \
pfunc; \
})
static void fail(int err, const char* func)
{
log_error("%s failed (%d / %s)!\n",
func, err, strerror(err));
exit(1);
}
#define CHECKRET(expr, cond, err, func) ({ \
int ret = (expr); \
if (!(cond)) \
fail((err), (func)); \
ret; \
})
static void* libc = NULL;
static void* pthread = NULL;
int connect(int socket, const struct sockaddr *address,
socklen_t address_len)
{
int connect_result = NEXT(libc, LIBC_SO, connect)
(socket, address, address_len);
if (connect_result == 0)
{
if (address->sa_family == AF_UNIX)
{
struct sockaddr_un *ua = (struct sockaddr_un*)address;
const char* path = ua->sun_path;
if (!*path)
path++;
//log_debug("connect(%s,%d)\n", path, address_len);
if (!strncmp(path, "/tmp/.X11-unix/X", 16))
{
needConfig();
log_debug("Found X connection!\n");
if (config.enable)
{
log_debug("Intercepting X connection!\n");
int pair[2];
CHECKRET(socketpair(AF_UNIX, SOCK_STREAM, 0, pair),
ret == 0, ret, "socketpair");
X11ConnData* data = calloc(1, sizeof(X11ConnData));
static int index = 0;
data->index = index++;
data->server = dup(socket);
data->client = pair[0];
CHECKRET(dup2(pair[1], socket),
ret >= 0, errno, "dup2");
CHECKRET(close(pair[1]),
ret == 0, errno, "close");
if (config.fork)
{
log_debug("Forking...\n");
pid_t pid = fork();
CHECKRET(pid, ret >= 0, errno, "fork");
if (pid == 0)
{
pid = getpid();
log_debug("In child (%d), forking again\n", pid);
pid_t pid2 = fork();
CHECKRET(pid2, ret >= 0, errno, "fork");
if (pid2)
{
log_debug("Second fork is %d\n", pid2);
exit(0);
}
log_debug("In child, double-fork OK\n");
struct rlimit r;
CHECKRET(getrlimit(RLIMIT_NOFILE, &r),
ret >= 0, errno, "getrlimit");
for (int n=3; n<(int)r.rlim_cur; n++)
if (n != data->server && n != data->client)
close(n); // Ignore error
log_debug("Running main loop.\n");
workThreadProc(data);
log_debug("Fork is exiting.\n");
exit(0);
}
else
{
close(data->server);
close(data->client);
free(data);
log_debug("In parent! Child is %d\n", pid);
CHECKRET(waitpid(pid, NULL, 0),
ret >= 0, errno, "waitpid");
return connect_result;
}
}
pthread_attr_t attr = {};
CHECKRET(NEXT(pthread, LIBPTHREAD_SO, pthread_attr_init)(&attr),
ret == 0, ret, "pthread_attr_init");
CHECKRET(NEXT(pthread, LIBPTHREAD_SO, pthread_attr_setdetachstate)(&attr, PTHREAD_CREATE_DETACHED),
ret == 0, ret, "pthread_attr_setdetachstate");
pthread_t workThread;
CHECKRET(NEXT(pthread, LIBPTHREAD_SO, pthread_create)
(&workThread, &attr, workThreadProc, data),
ret == 0, ret, "pthread_create");
NEXT(pthread, LIBPTHREAD_SO, pthread_attr_destroy)(&attr);
}
}
}
}
return connect_result;
}