@@ -73,3 +73,4 @@ subdir-y += libelf
subdir-$(CONFIG_HAS_DEVICE_TREE) += libfdt
obj-$(CONFIG_XSPLICE) += xsplice.o
+obj-$(CONFIG_XSPLICE) += xsplice_elf.o
new file mode 100644
@@ -0,0 +1,201 @@
+#include <xen/lib.h>
+#include <xen/errno.h>
+#include <xen/xsplice.h>
+#include <xen/xsplice_elf.h>
+
+#define return_(x) { printk(XENLOG_DEBUG "%s:%d rc: %d\n", \
+ __func__,__LINE__, x); return x; }
+
+struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
+ const char *name)
+{
+ unsigned int i;
+
+ for ( i = 0; i < elf->hdr->e_shnum; i++ )
+ {
+ if ( !strcmp(name, elf->sec[i].name) )
+ return &elf->sec[i];
+ }
+
+ return NULL;
+}
+
+static int elf_resolve_sections(struct xsplice_elf *elf, uint8_t *data)
+{
+ struct xsplice_elf_sec *sec;
+ unsigned int i;
+
+ sec = xmalloc_array(struct xsplice_elf_sec, elf->hdr->e_shnum);
+ if ( !sec )
+ {
+ printk(XENLOG_ERR "Could not allocate memory for section table!\n");
+ return_(-ENOMEM);
+ }
+
+ /* N.B. We also will ingest SHN_UNDEF sections. */
+ for ( i = 0; i < elf->hdr->e_shnum; i++ )
+ {
+ ssize_t delta = elf->hdr->e_shoff + i * elf->hdr->e_shentsize;
+
+ if ( delta + sizeof(Elf_Shdr) > elf->len )
+ return_(-EINVAL);
+
+ sec[i].sec = (Elf_Shdr *)(data + delta);
+ delta = sec[i].sec->sh_offset;
+
+ if ( delta > elf->len )
+ return_(-EINVAL);
+
+ sec[i].data = data + delta;
+ /* Name is populated in xsplice_elf_sections_name. */
+ sec[i].name = NULL;
+
+ if ( sec[i].sec->sh_type == SHT_SYMTAB )
+ {
+ if ( elf->symtab )
+ return_(-EINVAL);
+ elf->symtab = &sec[i];
+ /* elf->symtab->sec->sh_link would point to the right section
+ * but we hadn't finished parsing all the sections. */
+ if ( elf->symtab->sec->sh_link > elf->hdr->e_shnum )
+ return_(-EINVAL);
+ }
+ }
+ elf->sec = sec;
+ if ( !elf->symtab )
+ return_(-EINVAL);
+
+ /* There can be multiple SHT_STRTAB so pick the right one. */
+ elf->strtab = &sec[elf->symtab->sec->sh_link];
+
+ if ( elf->symtab->sec->sh_size == 0 || elf->symtab->sec->sh_entsize == 0 )
+ return_(-EINVAL);
+
+ if ( elf->symtab->sec->sh_entsize != sizeof(Elf_Sym) )
+ return_(-EINVAL);
+
+ return 0;
+}
+
+static int elf_resolve_section_names(struct xsplice_elf *elf, uint8_t *data)
+{
+ const char *shstrtab;
+ unsigned int i;
+ unsigned int offset, delta;
+
+ /* The elf->sec[0 -> e_shnum] structures have been verified by elf_resolve_sections */
+ /* Find file offset for section string table. */
+ offset = elf->sec[elf->hdr->e_shstrndx].sec->sh_offset;
+
+ if ( offset > elf->len )
+ return_(-EINVAL);
+
+ shstrtab = (const char *)(data + offset);
+
+ /* We could ignore the first as it is reserved.. */
+ for ( i = 0; i < elf->hdr->e_shnum; i++ )
+ {
+ delta = elf->sec[i].sec->sh_name;
+
+ if ( offset + delta > elf->len )
+ return_(-EINVAL);
+
+ elf->sec[i].name = shstrtab + delta;
+ }
+ return 0;
+}
+
+static int elf_get_sym(struct xsplice_elf *elf, uint8_t *data)
+{
+ struct xsplice_elf_sec *symtab_sec, *strtab_sec;
+ struct xsplice_elf_sym *sym;
+ unsigned int i, delta, offset;
+
+ symtab_sec = elf->symtab;
+
+ strtab_sec = elf->strtab;
+
+ /* Pointers arithmetic to get file offset. */
+ offset = strtab_sec->data - data;
+
+ ASSERT( offset == strtab_sec->sec->sh_offset );
+ /* symtab_sec->data was computed in elf_resolve_sections. */
+ ASSERT((symtab_sec->sec->sh_offset + data) == symtab_sec->data );
+
+ /* No need to check values as elf_resolve_sections did it. */
+ elf->nsym = symtab_sec->sec->sh_size / symtab_sec->sec->sh_entsize;
+
+ sym = xmalloc_array(struct xsplice_elf_sym, elf->nsym);
+ if ( !sym )
+ {
+ printk(XENLOG_ERR "%s: Could not allocate memory for symbols\n", elf->name);
+ return_(-ENOMEM);
+ }
+
+ for ( i = 0; i < elf->nsym; i++ )
+ {
+ Elf_Sym *s;
+
+ if ( i * sizeof(Elf_Sym) > elf->len )
+ return_(-EINVAL);
+
+ s = &((Elf_Sym *)symtab_sec->data)[i];
+
+ /* If st->name is STN_UNDEF it is zero, so the check will always be true. */
+ delta = s->st_name;
+ /* Offset has been computed earlier. */
+ if ( offset + delta > elf->len )
+ return_(-EINVAL);
+
+ sym[i].sym = s;
+ if ( s->st_name == STN_UNDEF )
+ sym[i].name = NULL;
+ else
+ sym[i].name = (const char *)data + ( delta + offset );
+ }
+ elf->sym = sym;
+
+ return 0;
+}
+
+int xsplice_elf_load(struct xsplice_elf *elf, uint8_t *data)
+{
+ int rc;
+
+ elf->hdr = (Elf_Ehdr *)data;
+
+ if ( sizeof(*elf->hdr) >= elf->len )
+ return_(-EINVAL);
+
+ if ( elf->hdr->e_shstrndx == SHN_UNDEF )
+ return_(-EINVAL);
+
+ /* Check that section name index is within the sections. */
+ if ( elf->hdr->e_shstrndx > elf->hdr->e_shnum )
+ return_(-EINVAL);
+
+ rc = elf_resolve_sections(elf, data);
+ if ( rc )
+ return rc;
+
+ rc = elf_resolve_section_names(elf, data);
+ if ( rc )
+ return rc;
+
+ rc = elf_get_sym(elf, data);
+ if ( rc )
+ return rc;
+
+ return 0;
+}
+
+void xsplice_elf_free(struct xsplice_elf *elf)
+{
+ xfree(elf->sec);
+ elf->sec = NULL;
+ xfree(elf->sym);
+ elf->sym = NULL;
+ elf->nsym = 0;
+ elf->name = NULL;
+ elf->len = 0;
+}
new file mode 100644
@@ -0,0 +1,37 @@
+#ifndef __XEN_XSPLICE_ELF_H__
+#define __XEN_XSPLICE_ELF_H__
+
+#include <xen/types.h>
+#include <xen/elfstructs.h>
+
+/* The following describes an Elf file as consumed by xSplice. */
+struct xsplice_elf_sec {
+ Elf_Shdr *sec; /* Hooked up in elf_resolve_sections. */
+ const char *name; /* Human readable name hooked in
+ elf_resolve_section_names. */
+ const char uint8_t *data; /* Pointer to the section (done by
+ elf_resolve_sections). */
+};
+
+struct xsplice_elf_sym {
+ Elf_Sym *sym;
+ const char *name;
+};
+
+struct xsplice_elf {
+ const char *name; /* Pointer to payload->name. */
+ ssize_t len; /* Length of the ELF file. */
+ Elf_Ehdr *hdr; /* ELF file. */
+ struct xsplice_elf_sec *sec; /* Array of sections, allocated by us. */
+ struct xsplice_elf_sym *sym; /* Array of symbols , allocated by us. */
+ unsigned int nsym;
+ struct xsplice_elf_sec *symtab;/* Pointer to .symtab section - aka to sec[x]. */
+ struct xsplice_elf_sec *strtab;/* Pointer to .strtab section - aka to sec[y]. */
+};
+
+struct xsplice_elf_sec *xsplice_elf_sec_by_name(const struct xsplice_elf *elf,
+ const char *name);
+int xsplice_elf_load(struct xsplice_elf *elf, uint8_t *data);
+void xsplice_elf_free(struct xsplice_elf *elf);
+
+#endif /* __XEN_XSPLICE_ELF_H__ */