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Date: Thu, 30 Dec 2010 06:23:17 +0900
From: HATAYAMA Daisuke <d.hatayama@...il.com>
To: linux-kernel@...r.kernel.org
Cc: tony.luck@...el.com, jdike@...toit.com, dhowells@...hat.com,
gerg@...pgear.com, roland@...hat.com, oleg@...hat.com,
mingo@...e.hu, viro@...iv.linux.org.uk, andi@...stfloor.org,
alan@...rguk.ukuu.org.uk, akpm@...ux-foundation.org,
kosaki.motohiro@...fujitsu.com, kamezawa.hiroyu@...fujitsu.com,
suzuki@...ibm.com, linux-arch@...r.kernel.org
Subject: [PATCH 3/4] elf core: Cleanup ELF handling
Cleanup ELF handling.
- Move all ELF header initialization in fill_extnum_info() into
fill_elf_header() and fill_elf_fdpic_header(), respectively.
- Rename fill_extnum_info() fill_section_header0(); the first entry
of section header table is reserved and used to record three kinds
of extensions. Extended numbering is here used to refer to the
extension for e_phnum only. Thus, we should use more general name
fill_section_header0().
- Use elf->e_shoff to determine whether to write section header
table. ELF specification defines elf->e_shoff is equal to 0 iff
there's no section header table.
Signed-off-by: HATAYAMA Daisuke <d.hatayama@...fujitsu.com>
---
fs/binfmt_elf.c | 64 ++++++++++++++++++-------------------------
fs/binfmt_elf_fdpic.c | 71 +++++++++++++++++++++---------------------------
2 files changed, 58 insertions(+), 77 deletions(-)
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index f311276..3ba6838 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1238,11 +1238,18 @@ static void fill_elf_header(struct elfhdr
*elf, int segs,
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
+ /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
+ * this, kernel supports extended numbering. Have a look at
+ * include/linux/elf.h for further information. */
if (segs < PN_XNUM) {
elf->e_phoff = sizeof(struct elfhdr);
elf->e_phnum = segs;
} else {
- elf->e_phoff = sizeof(struct elfhdr) + sizeof(struct elf_shdr);
+ elf->e_shoff = sizeof(struct elfhdr);
+ elf->e_shentsize = sizeof(struct elf_shdr);
+ elf->e_shnum = 1;
+ elf->e_shstrndx = SHN_UNDEF;
+ elf->e_phoff = elf->e_shoff + elf->e_shnum * elf->e_shentsize;
elf->e_phnum = PN_XNUM;
}
@@ -1844,21 +1851,15 @@ static struct vm_area_struct *next_vma(struct
vm_area_struct *this_vma,
return gate_vma;
}
-static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
- int segs)
+static void fill_section_header0(struct elfhdr *elf, struct elf_shdr *shdr0,
+ int segs)
{
- elf->e_shoff = sizeof(*elf);
- elf->e_shentsize = sizeof(*shdr4extnum);
- elf->e_shnum = 1;
- elf->e_shstrndx = SHN_UNDEF;
- elf->e_phoff = elf->e_shoff + elf->e_shnum * elf->e_shentsize;
-
- memset(shdr4extnum, 0, sizeof(*shdr4extnum));
-
- shdr4extnum->sh_type = SHT_NULL;
- shdr4extnum->sh_size = elf->e_shnum;
- shdr4extnum->sh_link = elf->e_shstrndx;
- shdr4extnum->sh_info = segs;
+ memset(shdr0, 0, sizeof(*shdr0));
+
+ shdr0->sh_type = SHT_NULL;
+ shdr0->sh_size = elf->e_shnum;
+ shdr0->sh_link = elf->e_shstrndx;
+ shdr0->sh_info = segs;
}
/*
@@ -1879,8 +1880,7 @@ static int elf_core_dump(struct coredump_params *cprm)
loff_t offset = 0, dataoff, foffset;
struct elf_note_info info;
struct elf_phdr *phdr4note = NULL;
- struct elf_shdr *shdr4extnum = NULL;
- Elf_Half e_phnum;
+ struct elf_shdr *shdr0 = NULL;
/*
* We no longer stop all VM operations.
@@ -1912,16 +1912,11 @@ static int elf_core_dump(struct coredump_params *cprm)
/* for notes section */
segs++;
- /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
- * this, kernel supports extended numbering. Have a look at
- * include/linux/elf.h for further information. */
- e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
-
/*
* Collect all the non-memory information about the process for the
* notes. This also sets up the file header.
*/
- if (!fill_note_info(elf, e_phnum, &info, cprm->signr, cprm->regs))
+ if (!fill_note_info(elf, segs, &info, cprm->signr, cprm->regs))
goto cleanup;
has_dumped = 1;
@@ -1930,11 +1925,7 @@ static int elf_core_dump(struct coredump_params *cprm)
fs = get_fs();
set_fs(KERNEL_DS);
- offset += sizeof(*elf); /* Elf header */
- if (e_phnum == PN_XNUM) /* Section header */
- offset += sizeof(struct elf_shdr);
- offset += segs * sizeof(struct elf_phdr); /* Program headers */
- foffset = offset;
+ foffset = offset = elf->e_phoff + segs * elf->e_phentsize;
/* Write notes phdr entry */
{
@@ -1952,22 +1943,21 @@ static int elf_core_dump(struct coredump_params *cprm)
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- if (e_phnum == PN_XNUM) {
- shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
- if (!shdr4extnum)
+ if (elf->e_shoff) {
+ shdr0 = kmalloc(sizeof(*shdr0), GFP_KERNEL);
+ if (!shdr0)
goto end_coredump;
- fill_extnum_info(elf, shdr4extnum, segs);
+ fill_section_header0(elf, shdr0, segs);
}
size += sizeof(*elf);
if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
goto end_coredump;
- if (e_phnum == PN_XNUM) {
- size += sizeof(*shdr4extnum);
+ if (elf->e_shoff) {
+ size += sizeof(*shdr0);
if (size > cprm->limit
- || !dump_write(cprm->file, shdr4extnum,
- sizeof(*shdr4extnum)))
+ || !dump_write(cprm->file, shdr0, sizeof(*shdr0)))
goto end_coredump;
}
@@ -2049,7 +2039,7 @@ end_coredump:
cleanup:
free_note_info(&info);
- kfree(shdr4extnum);
+ kfree(shdr0);
kfree(phdr4note);
kfree(elf);
out:
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 715d12d..59c7284 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1326,19 +1326,26 @@ static inline void
fill_elf_fdpic_header(struct elfhdr *elf, int segs)
elf->e_machine = ELF_ARCH;
elf->e_version = EV_CURRENT;
elf->e_entry = 0;
- elf->e_shoff = 0;
elf->e_flags = ELF_FDPIC_CORE_EFLAGS;
elf->e_ehsize = sizeof(struct elfhdr);
elf->e_phentsize = sizeof(struct elf_phdr);
- elf->e_shentsize = 0;
- elf->e_shnum = 0;
- elf->e_shstrndx = 0;
+ /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
+ * this, kernel supports extended numbering. Have a look at
+ * include/linux/elf.h for further information. */
if (segs < PN_XNUM) {
+ elf->e_shoff = 0;
+ elf->e_shentsize = 0;
+ elf->e_shnum = 0;
+ elf->e_shstrndx = 0;
elf->e_phoff = sizeof(struct elfhdr);
elf->e_phnum = segs;
} else {
- elf->e_phoff = sizeof(struct elfhdr) + sizeof(struct elf_shdr);
+ elf->e_shoff = sizeof(struct elfhdr);
+ elf->e_shentsize = sizeof(struct elf_shdr);
+ elf->e_shnum = 1;
+ elf->e_shstrndx = SHN_UNDEF;
+ elf->e_phoff = elf->e_shoff + elf->e_shnum * elf->e_shentsize;
elf->e_phnum = PN_XNUM;
}
@@ -1501,21 +1508,15 @@ static int elf_dump_thread_status(long signr,
struct elf_thread_status *t)
return sz;
}
-static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
- int segs)
+static void fill_section_header0(struct elfhdr *elf, struct elf_shdr *shdr0,
+ int segs)
{
- elf->e_shoff = sizeof(*elf);
- elf->e_shentsize = sizeof(*shdr4extnum);
- elf->e_shnum = 1;
- elf->e_shstrndx = SHN_UNDEF;
- elf->e_phoff = elf->e_shoff + elf->e_shnum * elf->e_shentsize;
-
- memset(shdr4extnum, 0, sizeof(*shdr4extnum));
-
- shdr4extnum->sh_type = SHT_NULL;
- shdr4extnum->sh_size = elf->e_shnum;
- shdr4extnum->sh_link = elf->e_shstrndx;
- shdr4extnum->sh_info = segs;
+ memset(shdr0, 0, sizeof(*shdr0));
+
+ shdr0->sh_type = SHT_NULL;
+ shdr0->sh_size = elf->e_shnum;
+ shdr0->sh_link = elf->e_shstrndx;
+ shdr0->sh_info = segs;
}
/*
@@ -1613,8 +1614,7 @@ static int elf_fdpic_core_dump(struct
coredump_params *cprm)
int thread_status_size = 0;
elf_addr_t *auxv;
struct elf_phdr *phdr4note = NULL;
- struct elf_shdr *shdr4extnum = NULL;
- Elf_Half e_phnum;
+ struct elf_shdr *shdr0 = NULL;
/*
* We no longer stop all VM operations.
@@ -1684,13 +1684,8 @@ static int elf_fdpic_core_dump(struct
coredump_params *cprm)
/* for notes section */
segs++;
- /* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
- * this, kernel supports extended numbering. Have a look at
- * include/linux/elf.h for further information. */
- e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
-
/* Set up header */
- fill_elf_fdpic_header(elf, e_phnum);
+ fill_elf_fdpic_header(elf, segs);
has_dumped = 1;
current->flags |= PF_DUMPCORE;
@@ -1729,11 +1724,7 @@ static int elf_fdpic_core_dump(struct
coredump_params *cprm)
fs = get_fs();
set_fs(KERNEL_DS);
- offset += sizeof(*elf); /* Elf header */
- if (e_phnum == PN_XNUM) /* Section header */
- offset += sizeof(struct elf_shdr);
- offset += segs * sizeof(struct elf_phdr); /* Program headers */
- foffset = offset;
+ foffset = offset = elf->e_phoff + segs * elf->e_phentsize;
/* Write notes phdr entry */
{
@@ -1755,22 +1746,22 @@ static int elf_fdpic_core_dump(struct
coredump_params *cprm)
/* Page-align dumped data */
dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
- if (e_phnum == PN_XNUM) {
- shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
- if (!shdr4extnum)
+ if (elf->e_shoff) {
+ shdr0 = kmalloc(sizeof(*shdr0), GFP_KERNEL);
+ if (!shdr0)
goto end_coredump;
- fill_extnum_info(elf, shdr4extnum, segs);
+ fill_section_header0(elf, shdr0, segs);
}
size += sizeof(*elf);
if (size > cprm->limit || !dump_write(cprm->file, elf, sizeof(*elf)))
goto end_coredump;
- if (e_phnum == PN_XNUM) {
- size += sizeof(*shdr4extnum);
+ if (elf->e_shoff) {
+ size += sizeof(*shdr0);
if (size > cprm->limit
- || !dump_write(cprm->file, shdr4extnum,
- sizeof(*shdr4extnum)))
+ || !dump_write(cprm->file, shdr0,
+ sizeof(*shdr0)))
goto end_coredump;
}
--
1.7.1
--
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