io_gdb: gdb://host:port/pid support; Add gdbr_{attach,detach,detach_pid,kill_pid} to gdbclient. (#7759)

Try to activate extended mode; Attach helper function requires extended mode to actually do something.

Tries to attach to the given pid in io_gdb.
This isn't proper, but it's better than running into the two-pid-vals-no-sync issue.

libr/debug/p/debug_gdb.c

@@ -206,9 +206,7 @@ static int r_debug_gdb_attach(RDebug *dbg, int pid) {
 }
 
 static int r_debug_gdb_detach(RDebug *dbg, int pid) {
-	gdbr_disconnect (desc);
-	free (reg_buf);
-	return true;
+	return gdbr_detach_pid (desc, pid);
 }
 
 static const char *r_debug_gdb_reg_profile(RDebug *dbg) {

libr/io/p/io_gdb.c

@@ -75,7 +75,7 @@ static int debug_gdb_write_at(const ut8 *buf, int sz, ut64 addr) {
 
 static RIODesc *__open(RIO *io, const char *file, int rw, int mode) {
 	RIOGdb *riog;
-	char host[128], *port, *p;
+	char host[128], *port, *pid;
 
 	if (!__plugin_open (io, file, 0))
 		return NULL;
@@ -87,13 +87,17 @@ static RIODesc *__open(RIO *io, const char *file, int rw, int mode) {
 	host [sizeof (host)-1] = '\0';
 	port = strchr (host , ':');
 	if (!port) {
-		eprintf ("Port not specified. Please use gdb://[host]:[port]\n");
+		eprintf ("Port not specified. Please use gdb://host:port[/port]\n");
 		return NULL;
 	}
 	*port = '\0';
 	port++;
-	p = strchr (port, '/');
-	if (p) *p = 0;
+
+	pid = strchr (port, '/');
+	if (pid) {
+		*pid = 0;
+		pid++;
+	}
 
 	if (r_sandbox_enable (0)) {
 		eprintf ("sandbox: Cannot use network\n");
@@ -102,8 +106,18 @@ static RIODesc *__open(RIO *io, const char *file, int rw, int mode) {
 	riog = R_NEW0 (RIOGdb);
 	gdbr_init (&riog->desc, false);
 	int i_port = atoi(port);
+	int i_pid = -1;
+	if (pid)
+		i_pid = atoi(pid);
+
 	if (gdbr_connect (&riog->desc, host, i_port) == 0) {
 		desc = &riog->desc;
+		desc->pid = i_pid;
+		if (pid) { // FIXME this is here for now because RDebug's pid and libgdbr's aren't properly synced.
+			int ret = gdbr_attach (desc, i_pid);
+			if (ret < 0)
+				eprintf ("gdbr: Failed to attach to PID %i\n", i_pid);
+		}
 		riogdb = r_io_desc_new (&r_io_plugin_gdb, riog->desc.sock->fd, file, rw, mode, riog);
 		return riogdb;
 	}

shlr/gdb/include/gdbclient/commands.h

@@ -19,12 +19,34 @@ int gdbr_connect(libgdbr_t *g, const char *server, int port);
  */
 int gdbr_disconnect(libgdbr_t *g);
 
+/*!
+ * \brief checks for extended mode availability
+ * \returns a failure code (currently -1) or 0 if call successfully
+ */
+int gdbr_check_extended_mode(libgdbr_t *g);
+
+/*!
+ * \brief attaches to a process
+ * \param pid of the process to attach to
+ * \returns a failure code (currently -1) or 0 if call successfully
+ */
+int gdbr_attach(libgdbr_t *g, int pid);
+
+/*!
+ * \brief detaches from a process
+ * \param pid of the process to detach from (only the multiprocess/pid variant)
+ * \returns a failure code (currently -1) or 0 if call successfully
+ */
+int gdbr_detach(libgdbr_t *g);
+int gdbr_detach_pid(libgdbr_t *g, int pid);
+
 /*!
  * \brief kills the process the remote gdbserver is debugging (TODO: handle pid)
+ * \param pid of the process to detach from (only the multiprocess/pid variant)
  * \retuns a failure code (currently -1) or 0 if call successfully
  */
 bool gdbr_kill(libgdbr_t *g);
-
+bool gdbr_kill_pid(libgdbr_t *g, int pid);
 
 // Commands
 int gdbr_continue(libgdbr_t *g, int thread_id);

shlr/gdb/include/gdbclient/core.h

@@ -13,6 +13,10 @@
 #include "../utils.h"
 #include "../arch.h"
 
+#define CMD_ATTACH	"vAttach;"
+#define CMD_DETACH_MP	"D;"
+#define CMD_KILL_MP	"vKill;"
+
 #define CMD_READREGS	"g"
 #define CMD_WRITEREGS	"G"
 #define CMD_READREG		"p"

shlr/gdb/include/gdbclient/responses.h

@@ -28,5 +28,6 @@ int handle_fstat(libgdbr_t* g);
 int handle_qSupported(libgdbr_t* g);
 int handle_setbp(libgdbr_t* g);
 int handle_removebp(libgdbr_t* g);
+int handle_attach(libgdbr_t* g);
 
 #endif  // RESPONSES_H

shlr/gdb/include/libgdbr.h

@@ -83,6 +83,8 @@ typedef struct libgdbr_stub_features_t {
 	bool BreakpointCommands;
 	// Cannot be determined with qSupported, found out on query
 	bool qC;
+
+	bool extended_mode;
 } libgdbr_stub_features_t;
 
 /*!

shlr/gdb/src/gdbclient/core.c

@@ -139,6 +139,9 @@ int gdbr_connect(libgdbr_t *g, const char *host, int port) {
 	if (strncmp (g->data, "OK", 2)) {
 		// return -1;
 	}
+
+	gdbr_check_extended_mode (g);
+
 	return ret;
 }
 
@@ -151,26 +154,170 @@ int gdbr_disconnect(libgdbr_t *g) {
 	return 0;
 }
 
-bool gdbr_kill(libgdbr_t *g) {
-	char buf[20];
+
+int gdbr_check_extended_mode(libgdbr_t *g) {
 	int ret;
+
+	// Activate extended mode if possible.
+	ret = send_msg (g, "!");
+	if (ret < 0) {
+		g->stub_features.extended_mode = false;
+		return ret;
+	}
+	read_packet (g);
+	ret = send_ack (g);
+	if (strncmp (g->data, "OK", 2)) {
+		g->stub_features.extended_mode = false;
+		return -1;
+	}
+
+	g->stub_features.extended_mode = true;
+	return 0;
+}
+
+
+int gdbr_attach(libgdbr_t *g, int pid) {
+	int ret;
+	char *cmd;
+	size_t buffer_size;
+
+	if (!g || !g->sock || !g->stub_features.multiprocess) {
+		return -1;
+	}
+
+	if (!g->stub_features.extended_mode) {
+		// vAttach needs extended mode to do anything.
+		return -2;
+	}
+
+	buffer_size = strlen (CMD_ATTACH) + (sizeof (int) * 2) + 1;
+	cmd = calloc (buffer_size, sizeof (char));
+	if (!cmd) {
+		return -1;
+	}
+
+	ret = snprintf (cmd, buffer_size, "%s%x", CMD_ATTACH, pid);
+	if (ret < 0) {
+		free(cmd);
+		return ret;
+	}
+
+	ret = send_msg (g, cmd);
+	free(cmd);
+	if (ret < 0) {
+		return ret;
+	}
+
+	if (read_packet (g) >= 0) {
+		return handle_attach (g);
+	}
+	return -1;
+}
+
+int gdbr_detach(libgdbr_t *g) {
+	int ret;
+
 	if (!g || !g->sock) {
+		return -1;
+	}
+
+	if (g->stub_features.multiprocess) {
+		if (!g->pid) {
+			return -1;
+		}
+		return gdbr_detach_pid (g, g->pid);
+	}
+
+	ret = send_msg (g, "D");
+	if (ret < 0) {
+		return -1;
+	}
+	return 0;
+}
+
+int gdbr_detach_pid(libgdbr_t *g, int pid) {
+	char *cmd;
+	int ret;
+	size_t buffer_size;
+
+	if (!g || !g->sock || !g->stub_features.multiprocess) {
+		return -1;
+	}
+
+	buffer_size = strlen (CMD_DETACH_MP) + (sizeof (pid) * 2) + 1;
+	cmd = calloc(buffer_size, sizeof (char));
+	if (!cmd) {
+		return -1;
+	}
+
+	if ((snprintf (cmd, buffer_size, "%s%x", CMD_DETACH_MP, g->pid)) < 0) {
+		free(cmd);
+		return -1;
+	}
+
+	ret = send_msg (g, cmd);
+	free(cmd);
+	if (ret < 0) {
+		return ret;
+	}
+
+	read_packet (g);
+	if ((ret = send_ack (g)) < 0) {
+		return ret;
+	}
+
+	if (strncmp (g->data, "OK", 2)) {
+		return -1;
+	}
+	return 0;
+}
+
+bool gdbr_kill(libgdbr_t *g) {
+	int ret;
+
+	if (!g || g->sock) {
 		return false;
 	}
+
 	if (g->stub_features.multiprocess) {
 		if (!g->pid) {
 			return false;
 		}
-		snprintf (buf, sizeof (buf) - 1, "vKill;%x", g->pid);
-	} else {
-		snprintf (buf, sizeof (buf) - 1, "k");
+		return gdbr_kill_pid (g, g->pid);
 	}
-	if ((ret = send_msg (g, buf)) < 0) {
+
+	ret = send_msg (g, "k");
+	if (ret < 0) {
 		return false;
 	}
-	if (!g->stub_features.multiprocess) {
-		return true;
+	return true;
+}
+
+bool gdbr_kill_pid(libgdbr_t *g, int pid) {
+	char *cmd;
+	int ret;
+	size_t buffer_size;
+
+	if (!g || !g->sock || !g->stub_features.multiprocess) {
+		return false;
 	}
+
+	buffer_size = strlen(CMD_KILL_MP) + (sizeof(pid) * 2) + 1;
+	cmd = calloc(buffer_size, sizeof (char));
+	if (!cmd) {
+		return false;
+	}
+
+	if ((snprintf (cmd, buffer_size, "%s%x", CMD_KILL_MP, g->pid)) < 0) {
+		free(cmd);
+		return false;
+	}
+	ret = send_msg (g, cmd);
+	free(cmd);
+	if (ret < 0) {
+		return false;
+	}
+
 	read_packet (g);
 	if ((ret = send_ack (g)) < 0) {
 		return false;

shlr/gdb/src/gdbclient/responses.c

@@ -170,3 +170,11 @@ int handle_setbp(libgdbr_t *g) {
 int handle_removebp(libgdbr_t *g) {
 	return send_ack (g);
 }
+
+int handle_attach(libgdbr_t *g) {
+	if (g->data_len == 3 && g->data[0] == 'E') {
+		send_ack (g);
+		return -1;
+	}
+	return send_ack (g);
+}

sys/rebuild.sh

@@ -1,5 +1,8 @@
 #!/bin/sh
 
+# Requires GNU Make, but some distros probably don't have the gmake symlink.
+[ -z "$MAKE" ] && MAKE=make
+
 while : ; do
 	if [ -f sys/rebuild.sh ]; then
 		break
@@ -13,14 +16,14 @@ done
 
 Rebuild() {
 	cd "$1" || exit 1
-	make clean
-	make -j8 || exit 1
+	$MAKE clean
+	$MAKE -j8 || exit 1
 	cd -
 }
 
 Build() {
 	cd "$1" || exit 1
-	make -j8 || exit 1
+	$MAKE -j8 || exit 1
 	cd -
 }
 
@@ -29,7 +32,7 @@ RebuildIOSDebug() {
 	# Rebuild libr/util
 	# Rebuild libr/core
 	Rebuild binr/radare2
-	make -C binr/radare2 ios-sign
+	$MAKE -C binr/radare2 ios-sign
 	if [ -n "${IOSIP}" ]; then
 		scp binr/radare2/radare2 root@"${IOSIP}:."
 	else