New version of libproc. Changes are:

* breakpoint setup support
* register query
* symbol to address mapping and vice-versa
* more misc utility functions based on their Solaris counterpart

Also, I've written some test cases.

Sponsored by:	The FreeBSD Foundation

1 files changed, 183 insertions, 0 deletions

diff --git a/lib/libproc/proc_bkpt.c b/lib/libproc/proc_bkpt.c
new file mode 100644
index 0000000..862a1bb
--- /dev/null
+++ b/lib/libproc/proc_bkpt.c
@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2010 The FreeBSD Foundation 
+ * All rights reserved. 
+ * 
+ * This software was developed by Rui Paulo under sponsorship from the
+ * FreeBSD Foundation. 
+ *  
+ * Redistribution and use in source and binary forms, with or without 
+ * modification, are permitted provided that the following conditions 
+ * are met: 
+ * 1. Redistributions of source code must retain the above copyright 
+ *    notice, this list of conditions and the following disclaimer. 
+ * 2. Redistributions in binary form must reproduce the above copyright 
+ *    notice, this list of conditions and the following disclaimer in the 
+ *    documentation and/or other materials provided with the distribution. 
+ * 
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 
+ * SUCH DAMAGE. 
+ */ 
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/types.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <machine/_inttypes.h>
+
+#include <assert.h>
+#include <err.h>
+#include <stdio.h>
+#include <errno.h>
+#include "_libproc.h"
+
+#if defined(__i386__) || defined(__amd64__)
+#define BREAKPOINT_INSTR	0xcc	/* int 0x3 */
+#define	BREAKPOINT_INSTR_SZ	1
+#else
+#error "Add support for your architecture"
+#endif
+
+int
+proc_bkptset(struct proc_handle *phdl, uintptr_t address,
+    unsigned long *saved)
+{
+	struct ptrace_io_desc piod;
+	unsigned long paddr, caddr;
+
+	*saved = 0;
+	if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
+	    phdl->status == PS_IDLE) {
+		errno = ENOENT;
+		return (-1);
+	}
+
+	/*
+	 * Read the original instruction.
+	 */
+	caddr = address;
+	paddr = 0;
+	piod.piod_op = PIOD_READ_I;
+	piod.piod_offs = (void *)caddr;
+	piod.piod_addr = &paddr;
+	piod.piod_len  = BREAKPOINT_INSTR_SZ;
+	if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
+		DPRINTF("ERROR: couldn't read instruction at address 0x%" PRIuPTR,
+		    address);
+		return (-1);
+	}
+	*saved = paddr;
+	/*
+	 * Write a breakpoint instruction to that address.
+	 */
+	caddr = address;
+	paddr = BREAKPOINT_INSTR;
+	piod.piod_op = PIOD_WRITE_I;
+	piod.piod_offs = (void *)caddr;
+	piod.piod_addr = &paddr;
+	piod.piod_len  = BREAKPOINT_INSTR_SZ;
+	if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
+		warn("ERROR: couldn't write instruction at address 0x%" PRIuPTR,
+		    address);
+		return (-1);
+	}
+
+	return (0);
+}
+
+int
+proc_bkptdel(struct proc_handle *phdl, uintptr_t address,
+    unsigned long saved)
+{
+	struct ptrace_io_desc piod;
+	unsigned long paddr, caddr;
+
+	if (phdl->status == PS_DEAD || phdl->status == PS_UNDEAD ||
+	    phdl->status == PS_IDLE) {
+		errno = ENOENT;
+		return (-1);
+	}
+	DPRINTF("removing breakpoint at 0x%lx\n", address);
+	/*
+	 * Overwrite the breakpoint instruction that we setup previously.
+	 */
+	caddr = address;
+	paddr = saved;
+	piod.piod_op = PIOD_WRITE_I;
+	piod.piod_offs = (void *)caddr;
+	piod.piod_addr = &paddr;
+	piod.piod_len  = BREAKPOINT_INSTR_SZ;
+	if (ptrace(PT_IO, proc_getpid(phdl), (caddr_t)&piod, 0) < 0) {
+		DPRINTF("ERROR: couldn't write instruction at address 0x%" PRIuPTR,
+		    address);
+		return (-1);
+	}
+ 
+	return (0);
+}
+
+/*
+ * Decrement pc so that we delete the breakpoint at the correct
+ * address, i.e. at the BREAKPOINT_INSTR address.
+ */
+void
+proc_bkptregadj(unsigned long *pc)
+{
+	*pc = *pc - BREAKPOINT_INSTR_SZ;
+}
+
+/*
+ * Step over the breakpoint.
+ */
+int
+proc_bkptexec(struct proc_handle *phdl, unsigned long saved)
+{
+	unsigned long pc;
+	unsigned long samesaved;
+	int status;
+
+	if (proc_regget(phdl, REG_PC, &pc) < 0) {
+		warn("ERROR: couldn't get PC register");
+		return (-1);
+	}
+	proc_bkptregadj(&pc);
+	if (proc_bkptdel(phdl, pc, saved) < 0) {
+		warn("ERROR: couldn't delete breakpoint");
+		return (-1);
+	}
+	/*
+	 * Go back in time and step over the new instruction just
+	 * set up by proc_bkptdel().
+	 */
+	proc_regset(phdl, REG_PC, pc);
+	if (ptrace(PT_STEP, proc_getpid(phdl), (caddr_t)1, 0) < 0) {
+		warn("ERROR: ptrace step failed");
+		return (-1);
+	}
+	status = proc_wstatus(phdl);
+	if (!WIFSTOPPED(status)) {
+		warn("ERROR: don't know why process stopped");
+		return (-1);
+	}
+	/*
+	 * Restore the breakpoint. The saved instruction should be
+	 * the same as the one that we were passed in.
+	 */
+	if (proc_bkptset(phdl, pc, &samesaved) < 0) {
+		warn("ERROR: couldn't restore breakpoint");
+		return (-1);
+	}
+	assert(samesaved == saved);
+
+	return (0);
+}