hook close() to prevent rude programs like ssh to close our pipes

those pipes are needed to talk with the dns-name allocator thread.

closes #9

src/allocator_thread.c

@@ -8,6 +8,7 @@
 #include <string.h>
 #include <stdint.h>
 #include <stddef.h>
+#include <errno.h>
 #include "allocator_thread.h"
 #include "shm.h"
 #include "debug.h"
@@ -147,8 +148,8 @@ struct at_msghdr {
 
 static pthread_t allocator_thread;
 static pthread_attr_t allocator_thread_attr;
-static int req_pipefd[2];
-static int resp_pipefd[2];
+int req_pipefd[2];
+int resp_pipefd[2];
 
 static int wait_data(int readfd) {
 	PFUNC();
@@ -158,7 +159,13 @@ static int wait_data(int readfd) {
 	int ret;
 	while((ret = select(readfd+1, &fds, NULL, NULL, NULL)) <= 0) {
 		if(ret < 0) {
-			perror("select2");
+			int e = errno;
+			if(e == EINTR) continue;
+#ifdef __GLIBC__
+			char emsg[1024];
+			char* x = strerror_r(errno, emsg, sizeof emsg);
+			dprintf(2, "select2: %s\n", x);
+#endif
 			return 0;
 		}
 	}

src/allocator_thread.h

@@ -6,6 +6,9 @@
 
 #define MSG_LEN_MAX 256
 
+extern int req_pipefd[2];
+extern int resp_pipefd[2];
+
 void at_init(void);
 void at_close(void);
 size_t at_get_host_for_ip(ip_type ip, char* readbuf);

src/core.h

@@ -82,6 +82,7 @@ int connect_proxy_chain (int sock, ip_type target_ip, unsigned short target_port
 
 void proxychains_write_log(char *str, ...);
 
+typedef int (*close_t)(int);
 typedef int (*connect_t)(int, const struct sockaddr *, socklen_t);
 typedef struct hostent* (*gethostbyname_t)(const char *);
 typedef int (*freeaddrinfo_t)(struct addrinfo *);

src/libproxychains.c

@@ -45,6 +45,7 @@
 #define     SOCKFAMILY(x)     (satosin(x)->sin_family)
 #define     MAX_CHAIN 512
 
+close_t true_close;
 connect_t true_connect;
 gethostbyname_t true_gethostbyname;
 getaddrinfo_t true_getaddrinfo;
@@ -113,6 +114,7 @@ static void do_init(void) {
 	SETUP_SYM(freeaddrinfo);
 	SETUP_SYM(gethostbyaddr);
 	SETUP_SYM(getnameinfo);
+	SETUP_SYM(close);
 	
 	init_l = 1;
 }
@@ -282,6 +284,16 @@ static void get_chain_data(proxy_data * pd, unsigned int *proxy_count, chain_typ
 
 /*******  HOOK FUNCTIONS  *******/
 
+int close(int fd) {
+	/* prevent rude programs (like ssh) from closing our pipes */
+	if(fd != req_pipefd[0]  && fd != req_pipefd[1] &&
+	   fd != resp_pipefd[0] && fd != resp_pipefd[1]) {
+		return true_close(fd);
+	}
+	errno = EINTR;
+	return -1;
+}
+
 int connect(int sock, const struct sockaddr *addr, unsigned int len) {
 	PFUNC();
 	int socktype = 0, flags = 0, ret = 0;