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[Qemu-devel] [PATCH v3 2/5] elf-ops.h: Add get_elf_note_type()
From: |
Liam Merwick |
Subject: |
[Qemu-devel] [PATCH v3 2/5] elf-ops.h: Add get_elf_note_type() |
Date: |
Tue, 15 Jan 2019 12:18:04 +0000 |
Introduce a routine which, given a pointer to a range of ELF Notes,
searches through them looking for a note matching the type specified
and returns a pointer to the matching ELF note.
get_elf_note_type() is used by elf_load[32|64]() to find the
specified note type required by the 'elf_note_fn' parameter
added in the previous commit.
Signed-off-by: Liam Merwick <address@hidden>
---
include/hw/elf_ops.h | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
index 3438d6f69e8d..690f9238c8cc 100644
--- a/include/hw/elf_ops.h
+++ b/include/hw/elf_ops.h
@@ -265,6 +265,51 @@ fail:
return ret;
}
+/*
+ * Given 'nhdr', a pointer to a range of ELF Notes, search through them
+ * for a note matching type 'elf_note_type' and return a pointer to
+ * the matching ELF note.
+ */
+static struct elf_note *glue(get_elf_note_type, SZ)(struct elf_note *nhdr,
+ elf_word note_size,
+ elf_word phdr_align,
+ elf_word elf_note_type)
+{
+ elf_word nhdr_size = sizeof(struct elf_note);
+ elf_word elf_note_entry_offset = 0;
+ elf_word note_type;
+ elf_word nhdr_namesz;
+ elf_word nhdr_descsz;
+
+ if (nhdr == NULL) {
+ return NULL;
+ }
+
+ note_type = nhdr->n_type;
+ while (note_type != elf_note_type) {
+ nhdr_namesz = nhdr->n_namesz;
+ nhdr_descsz = nhdr->n_descsz;
+
+ elf_note_entry_offset = nhdr_size +
+ QEMU_ALIGN_UP(nhdr_namesz, phdr_align) +
+ QEMU_ALIGN_UP(nhdr_descsz, phdr_align);
+
+ /*
+ * If the offset calculated in this iteration exceeds the
+ * supplied size, we are done and no matching note was found.
+ */
+ if (elf_note_entry_offset > note_size) {
+ return NULL;
+ }
+
+ /* skip to the next ELF Note entry */
+ nhdr = (void *)nhdr + elf_note_entry_offset;
+ note_type = nhdr->n_type;
+ }
+
+ return nhdr;
+}
+
static int glue(load_elf, SZ)(const char *name, int fd,
uint64_t (*elf_note_fn)(void *, void *, bool),
uint64_t (*translate_fn)(void *, uint64_t),
@@ -497,6 +542,36 @@ static int glue(load_elf, SZ)(const char *name, int fd,
high = addr + mem_size;
data = NULL;
+
+ } else if (ph->p_type == PT_NOTE && elf_note_fn) {
+ struct elf_note *nhdr = NULL;
+
+ file_size = ph->p_filesz; /* Size of the range of ELF notes */
+ data = g_malloc0(file_size);
+ if (ph->p_filesz > 0) {
+ if (lseek(fd, ph->p_offset, SEEK_SET) < 0) {
+ goto fail;
+ }
+ if (read(fd, data, file_size) != file_size) {
+ goto fail;
+ }
+ }
+
+ /*
+ * Search the ELF notes to find one with a type matching the
+ * value passed in via 'translate_opaque'
+ */
+ nhdr = (struct elf_note *)data;
+ assert(translate_opaque != NULL);
+ nhdr = glue(get_elf_note_type, SZ)(nhdr, file_size, ph->p_align,
+ *(uint64_t *)translate_opaque);
+ if (nhdr != NULL) {
+ bool is64 =
+ sizeof(struct elf_note) == sizeof(struct elf64_note);
+ elf_note_fn((void *)nhdr, (void *)&ph->p_align, is64);
+ }
+ g_free(data);
+ data = NULL;
}
}
--
1.8.3.1
- [Qemu-devel] [PATCH v3 0/4] QEMU changes to do PVH boot, Liam Merwick, 2019/01/15
- [Qemu-devel] [PATCH v3 2/5] elf-ops.h: Add get_elf_note_type(),
Liam Merwick <=
- [Qemu-devel] [PATCH v3 3/5] pvh: Add x86/HVM direct boot ABI header file, Liam Merwick, 2019/01/15
- [Qemu-devel] [PATCH v3 1/5] elf: Add optional function ptr to load_elf() to parse ELF notes, Liam Merwick, 2019/01/15
- [Qemu-devel] [PATCH v3 4/5] pvh: Boot uncompressed kernel using direct boot ABI, Liam Merwick, 2019/01/15
- [Qemu-devel] [PATCH v3 5/5] pvh: load initrd and expose it through fw_cfg, Liam Merwick, 2019/01/15
- Re: [Qemu-devel] [PATCH v3 0/4] QEMU changes to do PVH boot, Paolo Bonzini, 2019/01/15
- Re: [Qemu-devel] [PATCH v3 0/4] QEMU changes to do PVH boot, no-reply, 2019/01/20