Date: Fri, 25 Mar 2011 18:16:50 +0000 (UTC) From: Matthew D Fleming <mdf@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-7@freebsd.org Subject: svn commit: r220003 - in stable/7/sys: ddb gdb kern Message-ID: <201103251816.p2PIGo18089480@svn.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: mdf Date: Fri Mar 25 18:16:49 2011 New Revision: 220003 URL: http://svn.freebsd.org/changeset/base/220003 Log: MFC r218825. [The implementation change to kdb_sysctl_available() cannot be MFC'd as it requires a non-MFCable change (adding drains to sbuf)]. Modify kdb_trap() so that it re-calls the dbbe_trap function as long as the debugger back-end has changed. This means that switching from ddb to gdb no longer requires a "step" which can be dangerous on an already-crashed kernel. Also add a capability to get from the gdb back-end back to ddb, by typing ^C in the console window. While here, simplify kdb_sysctl_available() by using sbuf_new_for_sysctl(), and use strlcpy() instead of strncpy() since the strlcpy semantic is desired. Modified: stable/7/sys/ddb/db_command.c stable/7/sys/gdb/gdb_main.c stable/7/sys/gdb/gdb_packet.c stable/7/sys/kern/subr_kdb.c Directory Properties: stable/7/sys/ (props changed) stable/7/sys/cddl/contrib/opensolaris/ (props changed) stable/7/sys/contrib/dev/acpica/ (props changed) stable/7/sys/contrib/pf/ (props changed) Modified: stable/7/sys/ddb/db_command.c ============================================================================== --- stable/7/sys/ddb/db_command.c Fri Mar 25 18:16:36 2011 (r220002) +++ stable/7/sys/ddb/db_command.c Fri Mar 25 18:16:49 2011 (r220003) @@ -662,10 +662,16 @@ static void db_gdb(db_expr_t dummy1, boolean_t dummy2, db_expr_t dummy3, char *dummy4) { - if (kdb_dbbe_select("gdb") != 0) + if (kdb_dbbe_select("gdb") != 0) { db_printf("The remote GDB backend could not be selected.\n"); - else - db_printf("Step to enter the remote GDB backend.\n"); + return; + } + /* + * Mark that we are done in the debugger. kdb_trap() + * should re-enter with the new backend. + */ + db_cmd_loop_done = 1; + db_printf("(ctrl-c will return control to ddb)\n"); } static void Modified: stable/7/sys/gdb/gdb_main.c ============================================================================== --- stable/7/sys/gdb/gdb_main.c Fri Mar 25 18:16:36 2011 (r220002) +++ stable/7/sys/gdb/gdb_main.c Fri Mar 25 18:16:49 2011 (r220003) @@ -95,7 +95,17 @@ gdb_init(void) static int gdb_trap(int type, int code) { + jmp_buf jb; struct thread *thr_iter; + void *prev_jb; + + prev_jb = kdb_jmpbuf(jb); + if (setjmp(jb) != 0) { + printf("%s bailing, hopefully back to ddb!\n", __func__); + gdb_listening = 0; + (void)kdb_jmpbuf(prev_jb); + return (1); + } gdb_listening = 0; /* @@ -291,5 +301,6 @@ gdb_trap(int type, int code) break; } } + (void)kdb_jmpbuf(prev_jb); return (0); } Modified: stable/7/sys/gdb/gdb_packet.c ============================================================================== --- stable/7/sys/gdb/gdb_packet.c Fri Mar 25 18:16:36 2011 (r220002) +++ stable/7/sys/gdb/gdb_packet.c Fri Mar 25 18:16:49 2011 (r220003) @@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$"); #include <sys/systm.h> #include <sys/ctype.h> #include <sys/kdb.h> +#include <sys/ttydefaults.h> #include <machine/gdb_machdep.h> #include <machine/kdb.h> @@ -60,6 +61,17 @@ gdb_getc(void) do c = gdb_cur->gdb_getc(); while (c == -1); + + if (c == CTRL('C')) { + printf("Received ^C; trying to switch back to ddb.\n"); + + if (kdb_dbbe_select("ddb") != 0) + printf("The ddb backend could not be selected.\n"); + else { + printf("using longjmp, hope it works!\n"); + kdb_reenter(); + } + } return (c); } Modified: stable/7/sys/kern/subr_kdb.c ============================================================================== --- stable/7/sys/kern/subr_kdb.c Fri Mar 25 18:16:36 2011 (r220002) +++ stable/7/sys/kern/subr_kdb.c Fri Mar 25 18:16:49 2011 (r220003) @@ -141,10 +141,9 @@ kdb_sysctl_current(SYSCTL_HANDLER_ARGS) char buf[16]; int error; - if (kdb_dbbe != NULL) { - strncpy(buf, kdb_dbbe->dbbe_name, sizeof(buf)); - buf[sizeof(buf) - 1] = '\0'; - } else + if (kdb_dbbe != NULL) + strlcpy(buf, kdb_dbbe->dbbe_name, sizeof(buf)); + else *buf = '\0'; error = sysctl_handle_string(oidp, buf, sizeof(buf), req); if (error != 0 || req->newptr == NULL) @@ -491,13 +490,15 @@ kdb_thr_select(struct thread *thr) int kdb_trap(int type, int code, struct trapframe *tf) { + struct kdb_dbbe *be; register_t intr; #ifdef SMP int did_stop_cpus; #endif int handled; - if (kdb_dbbe == NULL || kdb_dbbe->dbbe_trap == NULL) + be = kdb_dbbe; + if (be == NULL || be->dbbe_trap == NULL) return (0); /* We reenter the debugger through kdb_reenter(). */ @@ -521,7 +522,15 @@ kdb_trap(int type, int code, struct trap makectx(tf, &kdb_pcb); kdb_thr_select(curthread); - handled = kdb_dbbe->dbbe_trap(type, code); + for (;;) { + handled = be->dbbe_trap(type, code); + if (be == kdb_dbbe) + break; + be = kdb_dbbe; + if (be == NULL || be->dbbe_trap == NULL) + break; + printf("Switching to %s back-end\n", be->dbbe_name); + } kdb_active--;
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201103251816.p2PIGo18089480>