Add support for gdb's memory searching capabilities to our in-kernel gdb

server.

Submitted by:	Daniel O'Connor <daniel.oconnor@isilon.com>
Reviewed by:	jhb
Sponsored by:	EMC Isilon Storage Division

3 files changed, 71 insertions, 0 deletions

diff --git a/sys/gdb/gdb_int.h b/sys/gdb/gdb_int.h
index d06943a..aa89402 100644
--- a/sys/gdb/gdb_int.h
+++ b/sys/gdb/gdb_int.h
@@ -60,6 +60,9 @@ void gdb_tx_begin(char);
 int gdb_tx_end(void);
 int gdb_tx_mem(const unsigned char *, size_t);
 void gdb_tx_reg(int);
+int gdb_rx_bindata(unsigned char *data, size_t datalen, size_t *amt);
+int gdb_search_mem(const unsigned char *addr, size_t size,
+    const unsigned char *pat, size_t patlen, const unsigned char **found);
 
 static __inline void
 gdb_tx_char(char c)
diff --git a/sys/gdb/gdb_main.c b/sys/gdb/gdb_main.c
index 4ed3272..f8f3836 100644
--- a/sys/gdb/gdb_main.c
+++ b/sys/gdb/gdb_main.c
@@ -53,6 +53,8 @@ SET_DECLARE(gdb_dbgport_set, struct gdb_dbgport);
 struct gdb_dbgport *gdb_cur = NULL;
 int gdb_listening = 0;
 
+static unsigned char gdb_bindata[64];
+
 static int
 gdb_init(void)
 {
@@ -254,6 +256,28 @@ gdb_trap(int type, int code)
 					gdb_tx_begin('l');
 					gdb_tx_end();
 				}
+			} else if (gdb_rx_equal("Search:memory:")) {
+				size_t patlen;
+				intmax_t addr, size;
+				const unsigned char *found;
+				if (gdb_rx_varhex(&addr) || gdb_rx_char() != ';' ||
+				    gdb_rx_varhex(&size) || gdb_rx_char() != ';' ||
+				    gdb_rx_bindata(gdb_bindata, sizeof(gdb_bindata), &patlen)) {
+					gdb_tx_err(EINVAL);
+					break;
+				}
+				if (gdb_search_mem((char *)(uintptr_t)addr, size, gdb_bindata, patlen, &found)) {
+					if (found == 0ULL)
+						gdb_tx_begin('0');
+					else {
+						gdb_tx_begin('1');
+						gdb_tx_char(',');
+						gdb_tx_hex((intmax_t)(uintptr_t)found, 8);
+					}
+					gdb_tx_end();
+				} else
+					gdb_tx_err(EIO);
+				break;
 			} else if (!gdb_cpu_query())
 				gdb_tx_empty();
 			break;
diff --git a/sys/gdb/gdb_packet.c b/sys/gdb/gdb_packet.c
index a62cc8d..73ee74f 100644
--- a/sys/gdb/gdb_packet.c
+++ b/sys/gdb/gdb_packet.c
@@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/systm.h>
 #include <sys/ctype.h>
 #include <sys/kdb.h>
+#include <sys/libkern.h>
 #include <sys/ttydefaults.h>
 
 #include <machine/gdb_machdep.h>
@@ -320,3 +321,46 @@ gdb_tx_reg(int regnum)
 	} else
 		gdb_tx_mem(regp, regsz);
 }
+
+/* Read binary data up until the end of the packet or until we have datalen decoded bytes */
+int
+gdb_rx_bindata(unsigned char *data, size_t datalen, size_t *amt)
+{
+	int c;
+
+	*amt = 0;
+
+	while (*amt < datalen) {
+		c = gdb_rx_char();
+		/* End of packet? */
+		if (c == -1)
+			break;
+		/* Escaped character up next */
+		if (c == '}') {
+			/* Truncated packet? Bail out */
+			if ((c = gdb_rx_char()) == -1)
+				return (1);
+			c ^= 0x20;
+		}
+		*(data++) = c & 0xff;
+		(*amt)++;
+	}
+
+	return (0);
+}
+
+int
+gdb_search_mem(const unsigned char *addr, size_t size, const unsigned char *pat, size_t patlen, const unsigned char **found)
+{
+	void *prev;
+	jmp_buf jb;
+	int ret;
+
+	prev = kdb_jmpbuf(jb);
+	ret = setjmp(jb);
+	if (ret == 0)
+		*found = memmem(addr, size, pat, patlen);
+
+	(void)kdb_jmpbuf(prev);
+	return ((ret == 0) ? 1 : 0);
+}