1 files changed, 385 insertions, 0 deletions

diff --git a/sys/kern/imgact_gzip.c b/sys/kern/imgact_gzip.c
new file mode 100644
index 0000000..57a5c1d
--- /dev/null
+++ b/sys/kern/imgact_gzip.c
@@ -0,0 +1,385 @@
+/*
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
+ * ----------------------------------------------------------------------------
+ *
+ * $FreeBSD$
+ *
+ * This module handles execution of a.out files which have been run through
+ * "gzip".  This saves diskspace, but wastes cpu-cycles and VM.
+ *
+ * TODO:
+ *	text-segments should be made R/O after being filled
+ *	is the vm-stuff safe ?
+ * 	should handle the entire header of gzip'ed stuff.
+ *	inflate isn't quite reentrant yet...
+ *	error-handling is a mess...
+ *	so is the rest...
+ *	tidy up unnecesary includes
+ */
+
+#include <sys/param.h>
+#include <sys/exec.h>
+#include <sys/imgact.h>
+#include <sys/imgact_aout.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/mman.h>
+#include <sys/mutex.h>
+#include <sys/proc.h>
+#include <sys/resourcevar.h>
+#include <sys/sysent.h>
+#include <sys/systm.h>
+#include <sys/vnode.h>
+#include <sys/inflate.h>
+
+#include <vm/vm.h>
+#include <vm/vm_param.h>
+#include <vm/pmap.h>
+#include <vm/vm_map.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_extern.h>
+
+struct imgact_gzip {
+	struct image_params *ip;
+	struct exec     a_out;
+	int             error;
+	int		gotheader;
+	int             where;
+	u_char         *inbuf;
+	u_long          offset;
+	u_long          output;
+	u_long          len;
+	int             idx;
+	u_long          virtual_offset, file_offset, file_end, bss_size;
+};
+
+static int exec_gzip_imgact(struct image_params *imgp);
+static int NextByte(void *vp);
+static int do_aout_hdr(struct imgact_gzip *);
+static int Flush(void *vp, u_char *, u_long siz);
+
+static int
+exec_gzip_imgact(imgp)
+	struct image_params *imgp;
+{
+	int             error, error2 = 0;
+	const u_char   *p = (const u_char *) imgp->image_header;
+	struct imgact_gzip igz;
+	struct inflate  infl;
+	struct vmspace *vmspace;
+
+	/* If these four are not OK, it isn't a gzip file */
+	if (p[0] != 0x1f)
+		return -1;	/* 0    Simply magic	 */
+	if (p[1] != 0x8b)
+		return -1;	/* 1    Simply magic	 */
+	if (p[2] != 0x08)
+		return -1;	/* 2    Compression method	 */
+	if (p[9] != 0x03)
+		return -1;	/* 9    OS compressed on	 */
+
+	/*
+	 * If this one contains anything but a comment or a filename marker,
+	 * we don't want to chew on it
+	 */
+	if (p[3] & ~(0x18))
+		return ENOEXEC;	/* 3    Flags		 */
+
+	/* These are of no use to us */
+	/* 4-7  Timestamp		 */
+	/* 8    Extra flags		 */
+
+	bzero(&igz, sizeof igz);
+	bzero(&infl, sizeof infl);
+	infl.gz_private = (void *) &igz;
+	infl.gz_input = NextByte;
+	infl.gz_output = Flush;
+
+	igz.ip = imgp;
+	igz.idx = 10;
+
+	if (p[3] & 0x08) {	/* skip a filename */
+		while (p[igz.idx++])
+			if (igz.idx >= PAGE_SIZE)
+				return ENOEXEC;
+	}
+	if (p[3] & 0x10) {	/* skip a comment */
+		while (p[igz.idx++])
+			if (igz.idx >= PAGE_SIZE)
+				return ENOEXEC;
+	}
+	igz.len = imgp->attr->va_size;
+
+	error = inflate(&infl);
+
+	/*
+	 * The unzipped file may not even have been long enough to contain
+	 * a header giving Flush() a chance to return error.  Check for this.
+	 */
+	if ( !igz.gotheader )
+		return ENOEXEC;
+
+	if ( !error ) {
+		vmspace = imgp->proc->p_vmspace;
+		error = vm_map_protect(&vmspace->vm_map,
+			(vm_offset_t) vmspace->vm_taddr,
+			(vm_offset_t) (vmspace->vm_taddr + 
+				      (vmspace->vm_tsize << PAGE_SHIFT)) ,
+			VM_PROT_READ|VM_PROT_EXECUTE,0);
+	}
+
+	if (igz.inbuf) {
+		error2 =
+			vm_map_remove(kernel_map, (vm_offset_t) igz.inbuf,
+			    (vm_offset_t) igz.inbuf + PAGE_SIZE);
+	}
+	if (igz.error || error || error2) {
+		printf("Output=%lu ", igz.output);
+		printf("Inflate_error=%d igz.error=%d error2=%d where=%d\n",
+		       error, igz.error, error2, igz.where);
+	}
+	if (igz.error)
+		return igz.error;
+	if (error)
+		return ENOEXEC;
+	if (error2)
+		return error2;
+	return 0;
+}
+
+static int
+do_aout_hdr(struct imgact_gzip * gz)
+{
+	int             error;
+	struct vmspace *vmspace;
+	vm_offset_t     vmaddr;
+
+	/*
+	 * Set file/virtual offset based on a.out variant. We do two cases:
+	 * host byte order and network byte order (for NetBSD compatibility)
+	 */
+	switch ((int) (gz->a_out.a_magic & 0xffff)) {
+	case ZMAGIC:
+		gz->virtual_offset = 0;
+		if (gz->a_out.a_text) {
+			gz->file_offset = PAGE_SIZE;
+		} else {
+			/* Bill's "screwball mode" */
+			gz->file_offset = 0;
+		}
+		break;
+	case QMAGIC:
+		gz->virtual_offset = PAGE_SIZE;
+		gz->file_offset = 0;
+		break;
+	default:
+		/* NetBSD compatibility */
+		switch ((int) (ntohl(gz->a_out.a_magic) & 0xffff)) {
+		case ZMAGIC:
+		case QMAGIC:
+			gz->virtual_offset = PAGE_SIZE;
+			gz->file_offset = 0;
+			break;
+		default:
+			gz->where = __LINE__;
+			return (-1);
+		}
+	}
+
+	gz->bss_size = roundup(gz->a_out.a_bss, PAGE_SIZE);
+
+	/*
+	 * Check various fields in header for validity/bounds.
+	 */
+	if (			/* entry point must lay with text region */
+	    gz->a_out.a_entry < gz->virtual_offset ||
+	    gz->a_out.a_entry >= gz->virtual_offset + gz->a_out.a_text ||
+
+	/* text and data size must each be page rounded */
+	    gz->a_out.a_text & PAGE_MASK || gz->a_out.a_data & PAGE_MASK) {
+		gz->where = __LINE__;
+		return (-1);
+	}
+	/*
+	 * text/data/bss must not exceed limits
+	 */
+	mtx_assert(&Giant, MA_OWNED);
+	if (			/* text can't exceed maximum text size */
+	    gz->a_out.a_text > maxtsiz ||
+
+	/* data + bss can't exceed rlimit */
+	    gz->a_out.a_data + gz->bss_size >
+	    gz->ip->proc->p_rlimit[RLIMIT_DATA].rlim_cur) {
+		gz->where = __LINE__;
+		return (ENOMEM);
+	}
+	/* Find out how far we should go */
+	gz->file_end = gz->file_offset + gz->a_out.a_text + gz->a_out.a_data;
+
+	/* copy in arguments and/or environment from old process */
+	error = exec_extract_strings(gz->ip);
+	if (error) {
+		gz->where = __LINE__;
+		return (error);
+	}
+	/*
+	 * Destroy old process VM and create a new one (with a new stack)
+	 */
+	exec_new_vmspace(gz->ip);
+
+	vmspace = gz->ip->proc->p_vmspace;
+
+	vmaddr = gz->virtual_offset;
+
+	error = vm_mmap(&vmspace->vm_map,
+			&vmaddr,
+			gz->a_out.a_text + gz->a_out.a_data,
+			VM_PROT_ALL, VM_PROT_ALL, MAP_ANON | MAP_FIXED,
+			0,
+			0);
+
+	if (error) {
+		gz->where = __LINE__;
+		return (error);
+	}
+
+	if (gz->bss_size != 0) {
+		/*
+		 * Allocate demand-zeroed area for uninitialized data.
+		 * "bss" = 'block started by symbol' - named after the 
+		 * IBM 7090 instruction of the same name.
+		 */
+		vmaddr = gz->virtual_offset + gz->a_out.a_text + 
+			gz->a_out.a_data;
+		error = vm_map_find(&vmspace->vm_map,
+				NULL,
+				0,
+				&vmaddr, 
+				gz->bss_size,
+				FALSE, VM_PROT_ALL, VM_PROT_ALL, 0);
+		if (error) {
+			gz->where = __LINE__;
+			return (error);
+		}
+	}
+	/* Fill in process VM information */
+	vmspace->vm_tsize = gz->a_out.a_text >> PAGE_SHIFT;
+	vmspace->vm_dsize = (gz->a_out.a_data + gz->bss_size) >> PAGE_SHIFT;
+	vmspace->vm_taddr = (caddr_t) (uintptr_t) gz->virtual_offset;
+	vmspace->vm_daddr = (caddr_t) (uintptr_t)
+			    (gz->virtual_offset + gz->a_out.a_text);
+
+	/* Fill in image_params */
+	gz->ip->interpreted = 0;
+	gz->ip->entry_addr = gz->a_out.a_entry;
+
+	gz->ip->proc->p_sysent = &aout_sysvec;
+
+	return 0;
+}
+
+static int
+NextByte(void *vp)
+{
+	int             error;
+	struct imgact_gzip *igz = (struct imgact_gzip *) vp;
+
+	if (igz->idx >= igz->len) {
+		igz->where = __LINE__;
+		return GZ_EOF;
+	}
+	if (igz->inbuf && igz->idx < (igz->offset + PAGE_SIZE)) {
+		return igz->inbuf[(igz->idx++) - igz->offset];
+	}
+	if (igz->inbuf) {
+		error = vm_map_remove(kernel_map, (vm_offset_t) igz->inbuf,
+			    (vm_offset_t) igz->inbuf + PAGE_SIZE);
+		if (error) {
+			igz->where = __LINE__;
+			igz->error = error;
+			return GZ_EOF;
+		}
+	}
+	igz->offset = igz->idx & ~PAGE_MASK;
+
+	error = vm_mmap(kernel_map,	/* map */
+			(vm_offset_t *) & igz->inbuf,	/* address */
+			PAGE_SIZE,	/* size */
+			VM_PROT_READ,	/* protection */
+			VM_PROT_READ,	/* max protection */
+			0,	/* flags */
+			(caddr_t) igz->ip->vp,	/* vnode */
+			igz->offset);	/* offset */
+	if (error) {
+		igz->where = __LINE__;
+		igz->error = error;
+		return GZ_EOF;
+	}
+	return igz->inbuf[(igz->idx++) - igz->offset];
+}
+
+static int
+Flush(void *vp, u_char * ptr, u_long siz)
+{
+	struct imgact_gzip *gz = (struct imgact_gzip *) vp;
+	u_char         *p = ptr, *q;
+	int             i;
+
+	/* First, find a a.out-header */
+	if (gz->output < sizeof gz->a_out) {
+		q = (u_char *) & gz->a_out;
+		i = min(siz, sizeof gz->a_out - gz->output);
+		bcopy(p, q + gz->output, i);
+		gz->output += i;
+		p += i;
+		siz -= i;
+		if (gz->output == sizeof gz->a_out) {
+			gz->gotheader = 1;
+			i = do_aout_hdr(gz);
+			if (i == -1) {
+				if (!gz->where)
+					gz->where = __LINE__;
+				gz->error = ENOEXEC;
+				return ENOEXEC;
+			} else if (i) {
+				gz->where = __LINE__;
+				gz->error = i;
+				return ENOEXEC;
+			}
+			if (gz->file_offset == 0) {
+				q = (u_char *) (uintptr_t) gz->virtual_offset;
+				copyout(&gz->a_out, q, sizeof gz->a_out);
+			}
+		}
+	}
+	/* Skip over zero-padded first PAGE if needed */
+	if (gz->output < gz->file_offset &&
+	    gz->output + siz > gz->file_offset) {
+		i = min(siz, gz->file_offset - gz->output);
+		gz->output += i;
+		p += i;
+		siz -= i;
+	}
+	if (gz->output >= gz->file_offset && gz->output < gz->file_end) {
+		i = min(siz, gz->file_end - gz->output);
+		q = (u_char *) (uintptr_t)
+		    (gz->virtual_offset + gz->output - gz->file_offset);
+		copyout(p, q, i);
+		gz->output += i;
+		p += i;
+		siz -= i;
+	}
+	gz->output += siz;
+	return 0;
+}
+
+
+/*
+ * Tell kern_execve.c about it, with a little help from the linker.
+ */
+static struct execsw gzip_execsw = {exec_gzip_imgact, "gzip"};
+EXEC_SET(execgzip, gzip_execsw);