Re: [Qemu-devel] [RFC][PATCH 06/16 v6] target-i386: Add API to write elf notes to core file

[Jan Kiszka]

On 2012-02-09 04:24, Wen Congyang wrote:
> The core file contains register's value. These APIs write registers to
> core file, and them will be called in the following patch.
> 
> Signed-off-by: Wen Congyang <address@hidden>
> ---
>  cpu-all.h               |    6 +
>  target-i386/arch-dump.c |  243 
> +++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 249 insertions(+), 0 deletions(-)
> 
> diff --git a/cpu-all.h b/cpu-all.h
> index 4cd7fbb..efb5ba3 100644
> --- a/cpu-all.h
> +++ b/cpu-all.h
> @@ -526,8 +526,14 @@ int cpu_memory_rw_debug(CPUState *env, target_ulong addr,
>  
>  #if defined(TARGET_I386)
>  void cpu_get_memory_mapping(MemoryMappingList *list, CPUState *env);
> +int cpu_write_elf64_note(int fd, CPUState *env, int cpuid,
> +                         target_phys_addr_t *offset);
> +int cpu_write_elf32_note(int fd, CPUState *env, int cpuid,
> +                         target_phys_addr_t *offset);

Again, some HAVE_XXX would be nicer. Maybe you put the whole block under
HAVE_GUEST_CORE_DUMP or so.

Is writing to file descriptor generic enough? What if we want to dump
via QMP, letting the receiver side decide about where to write it?

>  #else
>  #define cpu_get_memory_mapping(list, env)
> +#define cpu_write_elf64_note(fd, env, cpuid, offset) ({ -1; })
> +#define cpu_write_elf32_note(fd, env, cpuid, offset) ({ -1; })
>  #endif
>  
>  #endif /* CPU_ALL_H */
> diff --git a/target-i386/arch-dump.c b/target-i386/arch-dump.c
> index 2e921c7..4c0ff77 100644
> --- a/target-i386/arch-dump.c
> +++ b/target-i386/arch-dump.c
> @@ -11,8 +11,11 @@
>   *
>   */
>  
> +#include <elf.h>

Does this create a new dependency and break non-Linux hosts? Can you
pull the required bits into qemu's elf.h then?

> +
>  #include "cpu.h"
>  #include "cpu-all.h"
> +#include "monitor.h"
>  
>  /* PAE Paging or IA-32e Paging */
>  static void walk_pte(MemoryMappingList *list, target_phys_addr_t 
> pte_start_addr,
> @@ -252,3 +255,243 @@ void cpu_get_memory_mapping(MemoryMappingList *list, 
> CPUState *env)
>          walk_pde2(list, pde_addr, env->a20_mask, pse);
>      }
>  }
> +
> +#ifdef TARGET_X86_64
> +typedef struct {
> +    target_ulong r15, r14, r13, r12, rbp, rbx, r11, r10;
> +    target_ulong r9, r8, rax, rcx, rdx, rsi, rdi, orig_rax;
> +    target_ulong rip, cs, eflags;
> +    target_ulong rsp, ss;
> +    target_ulong fs_base, gs_base;
> +    target_ulong ds, es, fs, gs;
> +} x86_64_user_regs_struct;
> +
> +static int x86_64_write_elf64_note(int fd, CPUState *env, int id,
> +                                   target_phys_addr_t *offset)
> +{
> +    x86_64_user_regs_struct regs;
> +    Elf64_Nhdr *note;
> +    char *buf;
> +    int descsz, note_size, name_size = 5;
> +    const char *name = "CORE";
> +    int ret;
> +
> +    regs.r15 = env->regs[15];
> +    regs.r14 = env->regs[14];
> +    regs.r13 = env->regs[13];
> +    regs.r12 = env->regs[12];
> +    regs.r11 = env->regs[11];
> +    regs.r10 = env->regs[10];
> +    regs.r9  = env->regs[9];
> +    regs.r8  = env->regs[8];
> +    regs.rbp = env->regs[R_EBP];
> +    regs.rsp = env->regs[R_ESP];
> +    regs.rdi = env->regs[R_EDI];
> +    regs.rsi = env->regs[R_ESI];
> +    regs.rdx = env->regs[R_EDX];
> +    regs.rcx = env->regs[R_ECX];
> +    regs.rbx = env->regs[R_EBX];
> +    regs.rax = env->regs[R_EAX];
> +    regs.rip = env->eip;
> +    regs.eflags = env->eflags;
> +
> +    regs.orig_rax = 0; /* FIXME */
> +    regs.cs = env->segs[R_CS].selector;
> +    regs.ss = env->segs[R_SS].selector;
> +    regs.fs_base = env->segs[R_FS].base;
> +    regs.gs_base = env->segs[R_GS].base;
> +    regs.ds = env->segs[R_DS].selector;
> +    regs.es = env->segs[R_ES].selector;
> +    regs.fs = env->segs[R_FS].selector;
> +    regs.gs = env->segs[R_GS].selector;
> +
> +    descsz = 336; /* sizeof(prstatus_t) is 336 on x86_64 box */
> +    note_size = ((sizeof(Elf64_Nhdr) + 3) / 4 + (name_size + 3) / 4 +
> +                (descsz + 3) / 4) * 4;
> +    note = g_malloc(note_size);
> +
> +    memset(note, 0, note_size);
> +    note->n_namesz = cpu_to_le32(name_size);
> +    note->n_descsz = cpu_to_le32(descsz);
> +    note->n_type = cpu_to_le32(NT_PRSTATUS);
> +    buf = (char *)note;
> +    buf += ((sizeof(Elf64_Nhdr) + 3) / 4) * 4;
> +    memcpy(buf, name, name_size);
> +    buf += ((name_size + 3) / 4) * 4;
> +    memcpy(buf + 32, &id, 4); /* pr_pid */
> +    buf += descsz - sizeof(x86_64_user_regs_struct)-sizeof(target_ulong);
> +    memcpy(buf, &regs, sizeof(x86_64_user_regs_struct));
> +
> +    lseek(fd, *offset, SEEK_SET);
> +    ret = write(fd, note, note_size);
> +    g_free(note);
> +    if (ret < 0) {
> +        return -1;
> +    }
> +
> +    *offset += note_size;
> +
> +    return 0;
> +}
> +#endif
> +
> +typedef struct {
> +    uint32_t ebx, ecx, edx, esi, edi, ebp, eax;
> +    unsigned short ds, __ds, es, __es;
> +    unsigned short fs, __fs, gs, __gs;
> +    uint32_t orig_eax, eip;
> +    unsigned short cs, __cs;
> +    uint32_t eflags, esp;
> +    unsigned short ss, __ss;
> +} x86_user_regs_struct;
> +
> +static int x86_write_elf64_note(int fd, CPUState *env, int id,
> +                                target_phys_addr_t *offset)
> +{
> +    x86_user_regs_struct regs;
> +    Elf64_Nhdr *note;
> +    char *buf;
> +    int descsz, note_size, name_size = 5;
> +    const char *name = "CORE";
> +    int ret;
> +
> +    regs.ebp = env->regs[R_EBP] & 0xffffffff;
> +    regs.esp = env->regs[R_ESP] & 0xffffffff;
> +    regs.edi = env->regs[R_EDI] & 0xffffffff;
> +    regs.esi = env->regs[R_ESI] & 0xffffffff;
> +    regs.edx = env->regs[R_EDX] & 0xffffffff;
> +    regs.ecx = env->regs[R_ECX] & 0xffffffff;
> +    regs.ebx = env->regs[R_EBX] & 0xffffffff;
> +    regs.eax = env->regs[R_EAX] & 0xffffffff;
> +    regs.eip = env->eip & 0xffffffff;
> +    regs.eflags = env->eflags & 0xffffffff;
> +
> +    regs.cs = env->segs[R_CS].selector;
> +    regs.__cs = 0;
> +    regs.ss = env->segs[R_SS].selector;
> +    regs.__ss = 0;
> +    regs.ds = env->segs[R_DS].selector;
> +    regs.__ds = 0;
> +    regs.es = env->segs[R_ES].selector;
> +    regs.__es = 0;
> +    regs.fs = env->segs[R_FS].selector;
> +    regs.__fs = 0;
> +    regs.gs = env->segs[R_GS].selector;
> +    regs.__gs = 0;
> +
> +    descsz = 144; /* sizeof(prstatus_t) is 144 on x86 box */
> +    note_size = ((sizeof(Elf64_Nhdr) + 3) / 4 + (name_size + 3) / 4 +
> +                (descsz + 3) / 4) * 4;
> +    note = g_malloc(note_size);
> +
> +    memset(note, 0, note_size);
> +    note->n_namesz = cpu_to_le32(name_size);
> +    note->n_descsz = cpu_to_le32(descsz);
> +    note->n_type = cpu_to_le32(NT_PRSTATUS);
> +    buf = (char *)note;
> +    buf += ((sizeof(Elf64_Nhdr) + 3) / 4) * 4;
> +    memcpy(buf, name, name_size);
> +    buf += ((name_size + 3) / 4) * 4;
> +    memcpy(buf + 24, &id, 4); /* pr_pid */
> +    buf += descsz - sizeof(x86_user_regs_struct)-4;
> +    memcpy(buf, &regs, sizeof(x86_user_regs_struct));
> +
> +    lseek(fd, *offset, SEEK_SET);
> +    ret = write(fd, note, note_size);
> +    g_free(note);
> +    if (ret < 0) {
> +        return -1;
> +    }
> +
> +    *offset += note_size;
> +
> +    return 0;
> +}
> +
> +static int x86_write_elf32_note(int fd, CPUState *env, int id,
> +                                target_phys_addr_t *offset)
> +{
> +    x86_user_regs_struct regs;
> +    Elf32_Nhdr *note;
> +    char *buf;
> +    int descsz, note_size, name_size = 5;
> +    const char *name = "CORE";
> +    int ret;
> +
> +    regs.ebp = env->regs[R_EBP] & 0xffffffff;
> +    regs.esp = env->regs[R_ESP] & 0xffffffff;
> +    regs.edi = env->regs[R_EDI] & 0xffffffff;
> +    regs.esi = env->regs[R_ESI] & 0xffffffff;
> +    regs.edx = env->regs[R_EDX] & 0xffffffff;
> +    regs.ecx = env->regs[R_ECX] & 0xffffffff;
> +    regs.ebx = env->regs[R_EBX] & 0xffffffff;
> +    regs.eax = env->regs[R_EAX] & 0xffffffff;
> +    regs.eip = env->eip & 0xffffffff;
> +    regs.eflags = env->eflags & 0xffffffff;
> +
> +    regs.cs = env->segs[R_CS].selector;
> +    regs.__cs = 0;
> +    regs.ss = env->segs[R_SS].selector;
> +    regs.__ss = 0;
> +    regs.ds = env->segs[R_DS].selector;
> +    regs.__ds = 0;
> +    regs.es = env->segs[R_ES].selector;
> +    regs.__es = 0;
> +    regs.fs = env->segs[R_FS].selector;
> +    regs.__fs = 0;
> +    regs.gs = env->segs[R_GS].selector;
> +    regs.__gs = 0;
> +
> +    descsz = 144; /* sizeof(prstatus_t) is 144 on x86 box */
> +    note_size = ((sizeof(Elf32_Nhdr) + 3) / 4 + (name_size + 3) / 4 +
> +                (descsz + 3) / 4) * 4;
> +    note = g_malloc(note_size);
> +
> +    memset(note, 0, note_size);
> +    note->n_namesz = cpu_to_le32(name_size);
> +    note->n_descsz = cpu_to_le32(descsz);
> +    note->n_type = cpu_to_le32(NT_PRSTATUS);
> +    buf = (char *)note;
> +    buf += ((sizeof(Elf32_Nhdr) + 3) / 4) * 4;
> +    memcpy(buf, name, name_size);
> +    buf += ((name_size + 3) / 4) * 4;
> +    memcpy(buf + 24, &id, 4); /* pr_pid */
> +    buf += descsz - sizeof(x86_user_regs_struct)-4;
> +    memcpy(buf, &regs, sizeof(x86_user_regs_struct));
> +
> +    lseek(fd, *offset, SEEK_SET);
> +    ret = write(fd, note, note_size);
> +    g_free(note);
> +    if (ret < 0) {
> +        return -1;
> +    }
> +
> +    *offset += note_size;
> +
> +    return 0;
> +}
> +
> +int cpu_write_elf64_note(int fd, CPUState *env, int cpuid,
> +                         target_phys_addr_t *offset)
> +{
> +    int ret;
> +#ifdef TARGET_X86_64
> +    bool lma = !!(first_cpu->hflags & HF_LMA_MASK);
> +
> +    if (lma) {
> +        ret = x86_64_write_elf64_note(fd, env, cpuid, offset);
> +    } else {
> +#endif
> +        ret = x86_write_elf64_note(fd, env, cpuid, offset);
> +#ifdef TARGET_X86_64
> +    }
> +#endif
> +
> +    return ret;
> +}
> +
> +int cpu_write_elf32_note(int fd, CPUState *env, int cpuid,
> +                         target_phys_addr_t *offset)
> +{
> +    return x86_write_elf32_note(fd, env, cpuid, offset);
> +}

Minor nit: I think this wrapping is not needed, just fold
x86_write_elf32_note into this function.

Jan

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