/dev/ksyms; kernel symbols pseudo-device that masquerades as an a.out binary for ports that copy the symbol table to the end of kernel space (all that use DDB do this)

1 files changed, 187 insertions, 0 deletions

diff --git a/sys/dev/ksyms.c b/sys/dev/ksyms.c
new file mode 100644
index 00000000000..61792499b2a
--- /dev/null
+++ b/sys/dev/ksyms.c
@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 1998 Todd C. Miller <Todd.Miller@courtesan.com>
+ * All rights reserved.
+ *
+ * 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.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED ``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 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.
+ */
+
+/*
+ * kernel symbols special file (masquerades as a ZMAGIC a.out file)
+ *
+ * TODO: get boot loaders to put symbols on a page boundary so we
+ *       can mmap them too (also requires minor change to db_aout.c).
+ */
+
+#include <sys/param.h>
+#include <sys/buf.h>
+#include <sys/exec.h>
+#include <sys/systm.h>
+#include <sys/uio.h>
+#include <sys/malloc.h>
+#include <sys/fcntl.h>
+
+#include <machine/cpu.h>
+
+#include <vm/vm.h>
+
+extern char *esym;				/* end of symbol table */
+extern long end;				/* end of kernel */
+
+static struct exec *k1;				/* first page of /dev/ksyms */
+static caddr_t symtab = (caddr_t)(&end + 1);	/* start of symbol table */
+
+void	ksymsattach __P((int));
+int	ksymsopen __P((dev_t, int, int));
+int	ksymsclose __P((dev_t, int, int));
+int	ksymsread __P((dev_t, struct uio *, int));
+
+/*ARGSUSED*/
+void
+ksymsattach(num)
+	int num;
+{
+
+	if (esym > (char *)&end) {
+		/*
+		 * If we have a symbol table, fake up a struct exec.
+		 * We only fill in the following non-zero entries:
+		 *	a_text - fake text sement (struct exec only)
+		 *	a_syms - size of symbol table
+		 *
+		 * We assume __LDPGSZ is a multiple of NBPG (it is)
+		 */
+		k1 = (struct exec *)malloc(__LDPGSZ, M_TEMP, M_WAITOK);
+		bzero(k1, __LDPGSZ);
+		N_SETMAGIC(*k1, ZMAGIC, MID_MACHINE, 0);
+		k1->a_text = __LDPGSZ;
+		k1->a_syms = end;
+	}
+	return;
+}
+
+/*ARGSUSED*/
+int
+ksymsopen(dev, flag, mode)
+	dev_t dev;
+	int flag, mode;
+{
+
+	/* There are no non-zero minor devices */
+	if (minor(dev) != 0)
+		return (ENXIO);
+
+	/* This device is read-only */
+	if ((flag & FWRITE))
+		return (EPERM);
+		
+	/* Must have symbols at the end of the kernel to work */
+	if (esym <= (char *)&end)
+		return (ENXIO);
+
+	return (0);
+}
+
+/*ARGSUSED*/
+int
+ksymsclose(dev, flag, mode)
+	dev_t dev;
+	int flag, mode;
+{
+
+	return (0);
+}
+
+/*ARGSUSED*/
+int
+ksymsread(dev, uio, flags)
+	dev_t dev;
+	struct uio *uio;
+	int flags;
+{
+	register vm_offset_t v;
+	register size_t c, len;
+	int error = 0;
+
+#define iov	(uio->uio_iov)
+	while (uio->uio_resid > 0 && error == 0) {
+		/* Done with this iov?  Fill the next one... */
+		if (iov->iov_len == 0) {
+			uio->uio_iov++;
+			uio->uio_iovcnt--;
+			if (uio->uio_iovcnt < 0)
+				panic("ksymread");
+		}
+
+		/* Can't read past size of symbol table... */
+		if (uio->uio_offset >= (vm_offset_t)(esym - symtab) +
+		    k1->a_text)
+			break;
+
+		if (uio->uio_offset < k1->a_text) {
+			/*
+			 * If they asked for more that a_text,
+			 * read the part of k1 first, then the
+			 * part of symtab next time throug the loop.
+			 */
+			if (iov->iov_len + (size_t)uio->uio_offset >
+			    k1->a_text)
+				len = k1->a_text;
+			else
+				len = iov->iov_len;
+
+			/* Make offset relative to struct exec */
+			v = uio->uio_offset + (vm_offset_t)k1;
+			c = min(len, MAXPHYS);
+			error = uiomove((caddr_t)v, c, uio);
+		} else {
+			/* Make offset relative to symtab */
+			v = uio->uio_offset - k1->a_text +
+			    (vm_offset_t)symtab;
+			c = min(iov->iov_len, MAXPHYS);
+
+			/* Don't read past esym, truncate. */
+			if (v + c > (vm_offset_t)esym)
+				c = (vm_offset_t)esym - v;
+			error = uiomove((caddr_t)v, c, uio);
+		}
+	}
+	return (error);
+}
+
+/* XXX - can't do mmap until boot loaders make the symbol table page aligned */
+#if 0
+int
+ksymsmmap(dev, off, prot)
+	dev_t dev;
+	int off, prot;
+{
+#define ksyms_btop(x)	((vm_offset_t)(x) >> PGSHIFT
+	if ((unsigned)off >= (unsigned)(esym - symtab) + k1->a_text)
+		return (-1);
+
+	if ((unsigned)off < k1->a_text)
+		return (ksyms_btop(off + (unsigned)k1));
+	else
+		return (ksyms_btop(off + (unsigned)symtab - k1->a_text));
+}
+#endif