Messages in this thread |  | | | Date | Thu, 25 May 2006 01:36:08 +0530 | | From | "vamsi krishna" <> | | Subject | Re: Program to convert core file to executable. |
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Hello Daniel,
> Look at the program headers. Many of them probably have a file size of
I checked the PHDRS (readelf --segments) the following are the PHDRS of the core.exe
===============<BEGIN>================== Elf file type is EXEC (Executable file) Entry point 0x8048364 There are 11 program headers, starting at offset 52 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align NOTE 0x000194 0x00000000 0x00000000 0x00a48 0x00000 0 **LOAD 0x001000 0x08048000 0x00000000 0x00000 0x01000 R E 0x1000 LOAD 0x001000 0x08049000 0x00000000 0x01000 0x01000 RWE 0x1000 LOAD 0x002000 0xf649b000 0x00000000 0x01000 0x01000 RWE 0x1000 **LOAD 0x003000 0xf649c000 0x00000000 0x00000 0x132000 R E 0x1000 LOAD 0x003000 0xf65ce000 0x00000000 0x03000 0x03000 RWE 0x1000 LOAD 0x006000 0xf65d1000 0x00000000 0x03000 0x03000 RWE 0x1000 LOAD 0x009000 0xf65e8000 0x00000000 0x01000 0x01000 RWE 0x1000 **LOAD 0x00a000 0xf65e9000 0x00000000 0x00000 0x15000 R E 0x1000 LOAD 0x00a000 0xf65fe000 0x00000000 0x01000 0x01000 RWE 0x1000 LOAD 0x00b000 0xfeffe000 0x00000000 0x02000 0x02000 RWE 0x1000 ======================<END>============= o As you said I see some of the PHDRS are having FileSiz as zero, the first (1st **ed ) PHDR which is having virtual address 0x08048000 (this is obviously) the start of the text of the program, and its not having any memory in the core file.
o Does the other PHDRS for which FileSiz is zero correspond to the dynamic shared objects (.so) text ?? example in the above we see (2 **ed ) PHDR with VirtAddr as 0xf649c000 , so this means the text of some shared .so has been mapped here right?
o I have question about the memory mapping with permissions r--s or r--p (gconv used by glibc gets mapped like this some time) , so does the core file contains this information of the memory mappings?
o Is there a way I can findout the standard which the OS follows to write the core file?
o Rather than depending on the OS core file, hows your opinion on writing out all the mappings form /proc/<pid>/maps as PT_LOAD into a elf formatted file of type ET_EXEC, do you think this works? rather than converting core file to exe?
> > Of course, the kernel shouldn't crash! It sounds like a bug. >
Yes I can reproduce this , is there a bugzilla for kernel? (or should we report this at the buzilla of the distribution?)
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