[Crash-utility] Make note information human readable when help -D

["Zhou, Wenjian/周文剑"]

On 12/11/2014 06:27 AM, Dave Anderson wrote:

> First, please address all of these warnings:
>
> $ make warn
> ... [ cut ] ...
> cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6  netdump.c -Wall -O2 -Wstrict-prototypes -Wmissing-prototypes -fstack-protector -Wformat-security
> netdump.c: In function 'dump_Elf32_Nhdr':
> netdump.c:1987:4: warning: format not a string literal and no format arguments [-Wformat-security]
> netdump.c: In function 'dump_Elf64_Nhdr':
> netdump.c:2272:4: warning: format not a string literal and no format arguments [-Wformat-security]
> netdump.c:2303:4: warning: format not a string literal and no format arguments [-Wformat-security]
> ...
>

Hello Dave,

These warnings have been addressed.

> Secondly, for compressed kdumps in diskdump.c, you have this construct:
>
>         if (dd->machine_type == EM_386)
>                 display_note_elf32(dd->nt_prstatus_percpu[i],l_buf);
>         else if (dd->machine_type == EM_X86_64)
>                 display_note_elf64(dd->nt_prstatus_percpu[i],l_buf);
>
> But for ELF kdumps in netdump.c, display_note_elf32() are display_note_elf64()
> look to be called unconditionally.  What about the other architectures?
>

I distinguish the architectures by the struct size in display_note(). I wonder
if it is needed to add other conditions like machine_type.


	display_note(void *note_ptr, char *buf, int descsz)
	{
         	if (descsz == (2 * sizeof(struct x86_64_prstatus)))
                 	display_prstatus_elf64(note_ptr, buf);
	        else if (descsz == sizeof(struct x86_prstatus))
         	        display_prstatus_elf32(note_ptr, buf);
	        else if (descsz == (2 * sizeof(QEMUCPUState)))
         	        display_qemu_elf64(note_ptr, buf);
	        else if (descsz == sizeof(QEMUCPUState))
	                display_qemu_elf32(note_ptr, buf);
	}

> Also, are there any dumping facilities that actually utilize any of
> the nt_prstatus fields besides the registers and maybe the pid?:
>
> struct x86_64_prstatus {
>          int si_signo;
>          int si_code;
>          int si_errno;
>          short cursig;
>          unsigned long sigpend;
>          unsigned long sighold;
>          int pid;
>          int ppid;
>          int pgrp;
>          int sid;
>          struct timeval utime;
>          struct timeval stime;
>          struct timeval cutime;
>          struct timeval cstime;
>          struct x86_64_user_regs_struct regs;
>          int fpvalid;
> };
>
> For example, kdump just does this:
>
>          memset(&prstatus, 0, sizeof(prstatus));
>          prstatus.pr_pid = current->pid;
>          elf_core_copy_kernel_regs(&prstatus.pr_reg, regs);
>
> So I guess I wonder what is the point of displaying of all the other fields?
>

These patches are just used to make the original information readable.

I'm not sure whether it is a good idea to display only the registers contents here,
for help -r can show them well.

> Also, can you explain to me the difference between the register contents
> in the QEMUCPUState structure vs. the register contents in the NT_PRSTATUS
> note?
>

They are almost the same except that there are more information in QEMUCPUState.

> And related to that question, why doesn't your dump_qemu_elf() function
> display the rip and rflags registers?
>
It's my fault that I left them. And they have been added.

> Dave
>
> --
> Crash-utility mailing list
> Crash-utility at redhat.com
> https://www.redhat.com/mailman/listinfo/crash-utility


-- 
Thanks
Zhou Wenjian
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