1 files changed, 164 insertions, 0 deletions
diff --git a/contrib/elf2dmp/qemu_elf.c b/contrib/elf2dmp/qemu_elf.c
new file mode 100644
index 0000000000..e9c0d2534a
--- /dev/null
+++ b/contrib/elf2dmp/qemu_elf.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright (c) 2018 Virtuozzo International GmbH
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "err.h"
+#include "qemu_elf.h"
+
+#define QEMU_NOTE_NAME "QEMU"
+
+#ifndef ROUND_UP
+#define ROUND_UP(n, d) (((n) + (d) - 1) & -(0 ? (n) : (d)))
+#endif
+
+#ifndef DIV_ROUND_UP
+#define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
+#endif
+
+#define ELF_NOTE_SIZE(hdr_size, name_size, desc_size)   \
+    ((DIV_ROUND_UP((hdr_size), 4) +                     \
+      DIV_ROUND_UP((name_size), 4) +                    \
+      DIV_ROUND_UP((desc_size), 4)) * 4)
+
+int is_system(QEMUCPUState *s)
+{
+    return s->gs.base >> 63;
+}
+
+static char *nhdr_get_name(Elf64_Nhdr *nhdr)
+{
+    return (char *)nhdr + ROUND_UP(sizeof(*nhdr), 4);
+}
+
+static void *nhdr_get_desc(Elf64_Nhdr *nhdr)
+{
+    return nhdr_get_name(nhdr) + ROUND_UP(nhdr->n_namesz, 4);
+}
+
+static Elf64_Nhdr *nhdr_get_next(Elf64_Nhdr *nhdr)
+{
+    return (void *)((uint8_t *)nhdr + ELF_NOTE_SIZE(sizeof(*nhdr),
+                nhdr->n_namesz, nhdr->n_descsz));
+}
+
+Elf64_Phdr *elf64_getphdr(void *map)
+{
+    Elf64_Ehdr *ehdr = map;
+    Elf64_Phdr *phdr = (void *)((uint8_t *)map + ehdr->e_phoff);
+
+    return phdr;
+}
+
+Elf64_Half elf_getphdrnum(void *map)
+{
+    Elf64_Ehdr *ehdr = map;
+
+    return ehdr->e_phnum;
+}
+
+static int init_states(QEMU_Elf *qe)
+{
+    Elf64_Phdr *phdr = elf64_getphdr(qe->map);
+    Elf64_Nhdr *start = (void *)((uint8_t *)qe->map + phdr[0].p_offset);
+    Elf64_Nhdr *end = (void *)((uint8_t *)start + phdr[0].p_memsz);
+    Elf64_Nhdr *nhdr;
+    size_t cpu_nr = 0;
+
+    if (phdr[0].p_type != PT_NOTE) {
+        eprintf("Failed to find PT_NOTE\n");
+        return 1;
+    }
+
+    qe->has_kernel_gs_base = 1;
+
+    for (nhdr = start; nhdr < end; nhdr = nhdr_get_next(nhdr)) {
+        if (!strcmp(nhdr_get_name(nhdr), QEMU_NOTE_NAME)) {
+            QEMUCPUState *state = nhdr_get_desc(nhdr);
+
+            if (state->size < sizeof(*state)) {
+                eprintf("CPU #%zu: QEMU CPU state size %u doesn't match\n",
+                        cpu_nr, state->size);
+                /*
+                 * We assume either every QEMU CPU state has KERNEL_GS_BASE or
+                 * no one has.
+                 */
+                qe->has_kernel_gs_base = 0;
+            }
+            cpu_nr++;
+        }
+    }
+
+    printf("%zu CPU states has been found\n", cpu_nr);
+
+    qe->state = malloc(sizeof(*qe->state) * cpu_nr);
+    if (!qe->state) {
+        return 1;
+    }
+
+    cpu_nr = 0;
+
+    for (nhdr = start; nhdr < end; nhdr = nhdr_get_next(nhdr)) {
+        if (!strcmp(nhdr_get_name(nhdr), QEMU_NOTE_NAME)) {
+            qe->state[cpu_nr] = nhdr_get_desc(nhdr);
+            cpu_nr++;
+        }
+    }
+
+    qe->state_nr = cpu_nr;
+
+    return 0;
+}
+
+static void exit_states(QEMU_Elf *qe)
+{
+    free(qe->state);
+}
+
+int QEMU_Elf_init(QEMU_Elf *qe, const char *filename)
+{
+    int err = 0;
+    struct stat st;
+
+    qe->fd = open(filename, O_RDONLY, 0);
+    if (qe->fd == -1) {
+        eprintf("Failed to open ELF dump file \'%s\'\n", filename);
+        return 1;
+    }
+
+    fstat(qe->fd, &st);
+    qe->size = st.st_size;
+
+    qe->map = mmap(NULL, qe->size, PROT_READ | PROT_WRITE,
+            MAP_PRIVATE, qe->fd, 0);
+    if (qe->map == MAP_FAILED) {
+        eprintf("Failed to map ELF file\n");
+        err = 1;
+        goto out_fd;
+    }
+
+    if (init_states(qe)) {
+        eprintf("Failed to extract QEMU CPU states\n");
+        err = 1;
+        goto out_unmap;
+    }
+
+    return 0;
+
+out_unmap:
+    munmap(qe->map, qe->size);
+out_fd:
+    close(qe->fd);
+
+    return err;
+}
+
+void QEMU_Elf_exit(QEMU_Elf *qe)
+{
+    exit_states(qe);
+    munmap(qe->map, qe->size);
+    close(qe->fd);
+}