bsd-user: add stubbed out core dump support

Add a stubbed-out version of the bsd-user fork's core dump support. This
allows elfload.c to be almost the same between what's upstream and
what's in qemu-project upstream w/o the burden of reviewing the core
dump support.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

bsd-user/elfcore.c

@@ -0,0 +1,10 @@
+/* Stubbed out version of core dump support, explicitly in public domain */
+
+static int elf_core_dump(int signr, CPUArchState *env)
+{
+    struct elf_note en = { 0 };
+
+    bswap_note(&en);
+
+    return 0;
+}

bsd-user/elfload.c

@@ -26,15 +26,17 @@
 static abi_ulong target_auxents;   /* Where the AUX entries are in target */
 static size_t target_auxents_sz;   /* Size of AUX entries including AT_NULL */
 
+#include "target_arch_reg.h"
 #include "target_os_elf.h"
 #include "target_os_stack.h"
 #include "target_os_thread.h"
-
-#include "elf.h"
+#include "target_os_user.h"
 
 abi_ulong target_stksiz;
 abi_ulong target_stkbas;
 
+static int elf_core_dump(int signr, CPUArchState *env);
+
 static inline void memcpy_fromfs(void *to, const void *from, unsigned long n)
 {
     memcpy(to, from, n);
@@ -100,15 +102,25 @@ static void bswap_sym(struct elf_sym *sym)
     bswap16s(&sym->st_shndx);
 }
 
+static void bswap_note(struct elf_note *en)
+{
+    bswap32s(&en->n_namesz);
+    bswap32s(&en->n_descsz);
+    bswap32s(&en->n_type);
+}
+
 #else /* ! BSWAP_NEEDED */
 
 static void bswap_ehdr(struct elfhdr *ehdr) { }
 static void bswap_phdr(struct elf_phdr *phdr, int phnum) { }
 static void bswap_shdr(struct elf_shdr *shdr, int shnum) { }
 static void bswap_sym(struct elf_sym *sym) { }
+static void bswap_note(struct elf_note *en) { }
 
 #endif /* ! BSWAP_NEEDED */
 
+#include "elfcore.c"
+
 /*
  * 'copy_elf_strings()' copies argument/envelope strings from user
  * memory to free pages in kernel mem. These are in a format ready
@@ -834,6 +846,12 @@ int load_elf_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
 
     info->entry = elf_entry;
 
+#ifdef USE_ELF_CORE_DUMP
+    bprm->core_dump = &elf_core_dump;
+#else
+    bprm->core_dump = NULL;
+#endif
+
     return 0;
 }
 

bsd-user/qemu.h

@@ -51,6 +51,7 @@ extern enum BSDType bsd_type;
  * kernel
  */
 struct image_info {
+    abi_ulong load_bias;
     abi_ulong load_addr;
     abi_ulong start_code;
     abi_ulong end_code;
@@ -65,6 +66,9 @@ struct image_info {
     abi_ulong entry;
     abi_ulong code_offset;
     abi_ulong data_offset;
+    abi_ulong arg_start;
+    abi_ulong arg_end;
+    uint32_t  elf_flags;
 };
 
 #define MAX_SIGQUEUE_SIZE 1024
@@ -132,6 +136,7 @@ struct bsd_binprm {
         char **envp;
         char *filename;         /* (Given) Name of binary */
         char *fullpath;         /* Full path of binary */
+        int (*core_dump)(int, CPUArchState *);
 };
 
 void do_init_thread(struct target_pt_regs *regs, struct image_info *infop);
@@ -145,6 +150,7 @@ int load_elf_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
                     struct image_info *info);
 int load_flt_binary(struct bsd_binprm *bprm, struct target_pt_regs *regs,
                     struct image_info *info);
+int is_target_elf_binary(int fd);
 
 abi_long memcpy_to_target(abi_ulong dest, const void *src,
                           unsigned long len);