Add a few helper functions for zeroing kernel space and reading

from specified file offsets. Make use of these in load_elf.c.

3 files changed, 82 insertions, 37 deletions

diff --git a/sys/boot/common/bootstrap.h b/sys/boot/common/bootstrap.h
index 6e17be7..21845ce 100644
--- a/sys/boot/common/bootstrap.h
+++ b/sys/boot/common/bootstrap.h
@@ -76,6 +76,9 @@ char	*unargv(int argc, char *argv[]);
 void	hexdump(caddr_t region, size_t len);
 size_t	strlenout(vm_offset_t str);
 char	*strdupout(vm_offset_t str);
+void	kern_bzero(vm_offset_t dest, size_t len);
+int	kern_pread(int fd, vm_offset_t dest, size_t len, off_t off);
+void	*alloc_pread(int fd, off_t off, size_t len);
 
 /* bcache.c */
 int	bcache_init(u_int nblks, size_t bsize);
diff --git a/sys/boot/common/load_elf.c b/sys/boot/common/load_elf.c
index dd163a8..27cc527 100644
--- a/sys/boot/common/load_elf.c
+++ b/sys/boot/common/load_elf.c
@@ -241,10 +241,8 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
     int		ret;
     vm_offset_t firstaddr;
     vm_offset_t lastaddr;
-    void	*buf;
-    size_t	resid, chunk;
+    size_t	chunk;
     ssize_t	result;
-    vm_offset_t	dest;
     Elf_Addr	ssym, esym;
     Elf_Dyn	*dp;
     Elf_Addr	adp;
@@ -305,14 +303,10 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
 			       phdr[i].p_vaddr + off, fpcopy);
 	}
 	if (phdr[i].p_filesz > fpcopy) {
-	    if (lseek(ef->fd, (off_t)(phdr[i].p_offset + fpcopy),
-		      SEEK_SET) == -1) {
-		printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadexec: cannot seek\n");
-		goto out;
-	    }
-	    if (archsw.arch_readin(ef->fd, phdr[i].p_vaddr + off + fpcopy,
-		phdr[i].p_filesz - fpcopy) != (ssize_t)(phdr[i].p_filesz - fpcopy)) {
-		printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadexec: archsw.readin failed\n");
+	    if (kern_pread(ef->fd, phdr[i].p_vaddr + off + fpcopy,
+		phdr[i].p_filesz - fpcopy, phdr[i].p_offset + fpcopy) != 0) {
+		printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
+		    "_loadimage: read failed\n");
 		goto out;
 	    }
 	}
@@ -324,22 +318,8 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
 		(long)(phdr[i].p_vaddr + off + phdr[i].p_memsz - 1));
 #endif
 
-	    /* no archsw.arch_bzero */
-	    buf = malloc(PAGE_SIZE);
-	    if (buf == NULL) {
-		printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadimage: malloc() failed\n");
-		goto out;
-	    }
-	    bzero(buf, PAGE_SIZE);
-	    resid = phdr[i].p_memsz - phdr[i].p_filesz;
-	    dest = phdr[i].p_vaddr + off + phdr[i].p_filesz;
-	    while (resid > 0) {
-		chunk = min(PAGE_SIZE, resid);
-		archsw.arch_copyin(buf, dest, chunk);
-		resid -= chunk;
-		dest += chunk;
-	    }
-	    free(buf);
+	    kern_bzero(phdr[i].p_vaddr + off + phdr[i].p_filesz,
+		phdr[i].p_memsz - phdr[i].p_filesz);
 	}
 #ifdef ELF_VERBOSE
 	printf("\n");
@@ -361,16 +341,10 @@ __elfN(loadimage)(struct preloaded_file *fp, elf_file_t ef, u_int64_t off)
     chunk = ehdr->e_shnum * ehdr->e_shentsize;
     if (chunk == 0 || ehdr->e_shoff == 0)
 	goto nosyms;
-    shdr = malloc(chunk);
-    if (shdr == NULL)
-	goto nosyms;
-    if (lseek(ef->fd, (off_t)ehdr->e_shoff, SEEK_SET) == -1) {
-	printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadimage: cannot lseek() to section headers");
-	goto nosyms;
-    }
-    result = read(ef->fd, shdr, chunk);
-    if (result < 0 || (size_t)result != chunk) {
-	printf("\nelf" __XSTRING(__ELF_WORD_SIZE) "_loadimage: read section headers failed");
+    shdr = alloc_pread(ef->fd, ehdr->e_shoff, chunk);
+    if (shdr == NULL) {
+	printf("\nelf" __XSTRING(__ELF_WORD_SIZE)
+	    "_loadimage: failed to read section headers");
 	goto nosyms;
     }
     symtabindex = -1;
diff --git a/sys/boot/common/misc.c b/sys/boot/common/misc.c
index 9f38b60..f1a0491 100644
--- a/sys/boot/common/misc.c
+++ b/sys/boot/common/misc.c
@@ -93,6 +93,74 @@ strdupout(vm_offset_t str)
     return(result);
 }
 
+/* Zero a region in kernel space. */
+void
+kern_bzero(vm_offset_t dest, size_t len)
+{
+	char buf[256];
+	size_t chunk, resid;
+
+	bzero(buf, sizeof(buf));
+	resid = len;
+	while (resid > 0) {
+		chunk = min(sizeof(buf), resid);
+		archsw.arch_copyin(buf, dest, chunk);
+		resid -= chunk;
+		dest += chunk;
+	}
+}
+
+/*
+ * Read the specified part of a file to kernel space.  Unlike regular
+ * pread, the file pointer is advanced to the end of the read data,
+ * and it just returns 0 if successful.
+ */
+int
+kern_pread(int fd, vm_offset_t dest, size_t len, off_t off)
+{
+	ssize_t nread;
+
+	if (lseek(fd, off, SEEK_SET) == -1) {
+		printf("\nlseek failed\n");
+		return (-1);
+	}
+	nread = archsw.arch_readin(fd, dest, len);
+	if (nread != len) {
+		printf("\nreadin failed\n");
+		return (-1);
+	}
+	return (0);
+}
+
+/*
+ * Read the specified part of a file to a malloced buffer.  The file
+ * pointer is advanced to the end of the read data.
+ */
+void *
+alloc_pread(int fd, off_t off, size_t len)
+{
+	void *buf;
+	ssize_t nread;
+
+	buf = malloc(len);
+	if (buf == NULL) {
+		printf("\nmalloc(%d) failed\n", (int)len);
+		return (NULL);
+	}
+	if (lseek(fd, off, SEEK_SET) == -1) {
+		printf("\nlseek failed\n");
+		free(buf);
+		return (NULL);
+	}
+	nread = read(fd, buf, len);
+	if (nread != len) {
+		printf("\nread failed\n");
+		free(buf);
+		return (NULL);
+	}
+	return (buf);
+}
+
 /*
  * Display a region in traditional hexdump format.
  */