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Add extended segment support to gcore

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A follow-up to r303099, D7255.  Basically, apply the exact same change, with
the exact same rationale, to gcore.  gcore's elfcore.c is largely a clone of
the kernel imgact_elf coredump facility.

Reviewed by:	emaste (earlier version, not substantially different)
Requested by:	jhb
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D7265
This commit is contained in:
Conrad Meyer 2016-07-20 22:03:45 +00:00
parent 56e807d918
commit bd0371c964
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=303114
1 changed files with 31 additions and 3 deletions
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34
usr.bin/gcore/elfcore.c
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@ -213,6 +213,8 @@ elf_coredump(int efd __unused, int fd, pid_t pid)
*/
sb = sbuf_new_auto();
hdrsize = sizeof(Elf_Ehdr) + sizeof(Elf_Phdr) * (1 + seginfo.count);
if (seginfo.count + 1 >= PN_XNUM)
hdrsize += sizeof(Elf_Shdr);
/* Start header + notes section. */
sbuf_start_section(sb, NULL);
/* Make empty header subsection. */
@ -423,10 +425,10 @@ elf_puthdr(pid_t pid, vm_map_entry_t map, void *hdr, size_t hdrsize,
{
Elf_Ehdr *ehdr;
Elf_Phdr *phdr;
Elf_Shdr *shdr;
struct phdr_closure phc;
ehdr = (Elf_Ehdr *)hdr;
phdr = (Elf_Phdr *)((char *)hdr + sizeof(Elf_Ehdr));
ehdr->e_ident[EI_MAG0] = ELFMAG0;
ehdr->e_ident[EI_MAG1] = ELFMAG1;
@ -446,14 +448,40 @@ elf_puthdr(pid_t pid, vm_map_entry_t map, void *hdr, size_t hdrsize,
ehdr->e_flags = 0;
ehdr->e_ehsize = sizeof(Elf_Ehdr);
ehdr->e_phentsize = sizeof(Elf_Phdr);
ehdr->e_phnum = numsegs + 1;
ehdr->e_shentsize = sizeof(Elf_Shdr);
ehdr->e_shnum = 0;
ehdr->e_shstrndx = SHN_UNDEF;
if (numsegs + 1 < PN_XNUM) {
ehdr->e_phnum = numsegs + 1;
ehdr->e_shnum = 0;
} else {
ehdr->e_phnum = PN_XNUM;
ehdr->e_shnum = 1;
ehdr->e_shoff = ehdr->e_phoff +
(numsegs + 1) * ehdr->e_phentsize;
shdr = (Elf_Shdr *)((char *)hdr + ehdr->e_shoff);
memset(shdr, 0, sizeof(*shdr));
/*
* A special first section is used to hold large segment and
* section counts. This was proposed by Sun Microsystems in
* Solaris and has been adopted by Linux; the standard ELF
* tools are already familiar with the technique.
*
* See table 7-7 of the Solaris "Linker and Libraries Guide"
* (or 12-7 depending on the version of the document) for more
* details.
*/
shdr->sh_type = SHT_NULL;
shdr->sh_size = ehdr->e_shnum;
shdr->sh_link = ehdr->e_shstrndx;
shdr->sh_info = numsegs + 1;
}
/*
* Fill in the program header entries.
*/
phdr = (Elf_Phdr *)((char *)hdr + ehdr->e_phoff);
/* The note segement. */
phdr->p_type = PT_NOTE;