On 01/14/2016 09:47 PM, Konrad Rzeszutek Wilk wrote:
From: Ross Lagerwall <ross.lagerw...@citrix.com>
Add Elf routines and data structures in preparation for loading an
xSplice payload.
We also add an macro that will print where we failed during
the ELF parsing.
Signed-off-by: Ross Lagerwall <ross.lagerw...@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
---
v2: - With the #define ELFSIZE in the ARM file we can use the common
#defines instead of using #ifdef CONFIG_ARM_32.
- Add checks for ELF file.
- Add name to be printed.
- Add len for easier ELF checks.
- Expand on the checks. Add macro.
---
diff --git a/xen/common/xsplice_elf.c b/xen/common/xsplice_elf.c
new file mode 100644
index 0000000..a5e9d63
--- /dev/null
+++ b/xen/common/xsplice_elf.c
@@ -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");
Shouldn't this printk be removed if you're using return_?
+ 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;
+}
+
snip
+
+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);
Shouldn't this printk be removed if you're using return_?
--
Ross Lagerwall
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