[Qemu-devel] [PATCH 10/12 v15] target-i386: Add API to get note's size

[Wen Congyang <wency@cn.fujitsu.com>]

We should know where the note and memory is stored before writing
them to vmcore. If we know this, we can avoid using lseek() when
creating vmcore.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 cpu-all.h               |    6 ++++++
 target-i386/arch_dump.c |   33 +++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 0 deletions(-)

diff --git a/cpu-all.h b/cpu-all.h
index 7e07c91..2b77f66 100644
--- a/cpu-all.h
+++ b/cpu-all.h
@@ -553,6 +553,7 @@ int cpu_write_elf64_qemunote(write_core_dump_function f, CPUArchState *env,
 int cpu_write_elf32_qemunote(write_core_dump_function f, CPUArchState *env,
                              void *opaque);
 int cpu_get_dump_info(ArchDumpInfo *info);
+size_t cpu_get_note_size(int class, int machine, int nr_cpus);
 #else
 static inline int cpu_write_elf64_note(write_core_dump_function f,
                                        CPUArchState *env, int cpuid,
@@ -586,6 +587,11 @@ static inline int cpu_get_dump_info(ArchDumpInfo *info)
 {
     return -1;
 }
+
+static inline int cpu_get_note_size(int class, int machine, int nr_cpus)
+{
+    return -1;
+}
 #endif
 
 #endif /* CPU_ALL_H */
diff --git a/target-i386/arch_dump.c b/target-i386/arch_dump.c
index e378579..135d855 100644
--- a/target-i386/arch_dump.c
+++ b/target-i386/arch_dump.c
@@ -414,3 +414,36 @@ int cpu_get_dump_info(ArchDumpInfo *info)
 
     return 0;
 }
+
+size_t cpu_get_note_size(int class, int machine, int nr_cpus)
+{
+    int name_size = 5; /* "CORE" or "QEMU" */
+    size_t elf_note_size = 0;
+    size_t qemu_note_size = 0;
+    int elf_desc_size = 0;
+    int qemu_desc_size = 0;
+    int note_head_size;
+
+    if (class == ELFCLASS32) {
+        note_head_size = sizeof(Elf32_Nhdr);
+    } else {
+        note_head_size = sizeof(Elf64_Nhdr);
+    }
+
+    if (machine == EM_386) {
+        elf_desc_size = sizeof(x86_elf_prstatus);
+    }
+#ifdef TARGET_X86_64
+    else {
+        elf_desc_size = sizeof(x86_64_elf_prstatus);
+    }
+#endif
+    qemu_desc_size = sizeof(QEMUCPUState);
+
+    elf_note_size = ((note_head_size + 3) / 4 + (name_size + 3) / 4 +
+                     (elf_desc_size + 3) / 4) * 4;
+    qemu_note_size = ((note_head_size + 3) / 4 + (name_size + 3) / 4 +
+                      (qemu_desc_size + 3) / 4) * 4;
+
+    return (elf_note_size + qemu_note_size) * nr_cpus;
+}
-- 
1.7.1