binfmt_elf.c: core file shrinking

PATCH In review Thanh-Lam NGUYEN 2 participants 5 messages Oct 11, 2011 – Oct 18, 2011

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Thanh-Lam NGUYEN

author

2011-10-11 15:36 UTC #0 lore raw

PATCH 1/1 binfmt_elf.c: core file shrinking

The vma_shrink function looks for the 1st allocated and the last allocated page. Only this part is dumped to the disk (the virual start address and the size are dupdated to reflect the new dumped information).

Signed-off-by Thanh Lam NGUYEN <[email protected]>

Signed-off-by Benjamin ZORES <[email protected]>

---
 linux/fs/binfmt_elf.c |   54
++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 4 deletions(-)

fs/binfmt_elf.c +42 -0

@@ -1085,6 +1085,48 @@
  * Jeremy Fitzhardinge <[email protected]>
  */
 
+/*
+ * Search for 1st and last allocated page from vma_start to vma_end.
+ * Update vma_start and vma_end to reflect the result.
+ */
+void vma_shrink(struct vm_area_struct *vma, unsigned long *vma_start,
+		unsigned long *vma_end)
+{
+	int allocated;
+	unsigned long start, addr, end;
+
+	allocated = 0;
+	start = end = *vma_start;
+	for (addr = *vma_start; _addr < *vma_end; addr += PAGE_SIZE) {
+		struct page *page;
+		if (get_user_pages(current, current->mm, addr, 1, 0, 1,
+				   &page, NULL) <= 0) {
+			/* NO PAGE */
+			if (!allocated)
+				start = addr;
+		} else {
+			if (page == ZERO_PAGE(0)) {
+				/* ZERO PAGE */
+				if (!allocated)
+					start = addr;
+			} else {
+				/* ALLOCATED PAGE */
+				if (!allocated)
+					start = addr;
+				end = addr;
+				allocated = 1;
+			}
+			page_cache_release(page);
+		}
+	}
+	if (end < start)
+		end = start;
+	if (allocated)
+		end += PAGE_SIZE;
+	*vma_start = start;
+	*vma_end = end;
+}
+
 /*
  * Decide what to dump of a segment, part, all or none.
  */

@@ -1980,13 +2022,19 @@ static int elf_core_dump(struct coredump_params

*cprm)
for (vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
struct elf_phdr phdr;
+ unsigned long start = vma->vm_start;
+ unsigned long end = vma->vm_end;
phdr.p_type = PT_LOAD;
phdr.p_offset = offset;
- phdr.p_vaddr = vma->vm_start;
phdr.p_paddr = 0;
phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags);
- phdr.p_memsz = vma->vm_end - vma->vm_start;
+ if (phdr.p_filesz) {
+ vma_shrink(vma, &start, &end);
+ phdr.p_filesz = end-start;
+ }
+ phdr.p_vaddr = start;
+ phdr.p_memsz = vma->vm_end - phdr.p_vaddr;
offset += phdr.p_filesz;
phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0; if (vma->vm_flags & VM_WRITE)
@@ -2018,11 +2066,15 @@ static int elf_core_dump(struct coredump_params *cprm)
for (vma = first_vma(current, gate_vma); vma != NULL;
vma = next_vma(vma, gate_vma)) {
unsigned long addr;
+ unsigned long start;
unsigned long end;
- end = vma->vm_start + vma_dump_size(vma, cprm->mm_flags);
+ start = vma->vm_start;
+ end = start + vma_dump_size(vma, cprm->mm_flags);
+ if (start < end)
+ vma_shrink(vma, &start, &end);
- for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
+ for (addr = start; addr < end; addr += PAGE_SIZE) {
struct page *page;
int stop;

---
=~=~=~=~=~=~=~=~=~=~=~=~==~=~=~=~=~=~=~=~=~=~=~=~=~=~=
Thanh lam NGUYEN
Prestataire externe ALTEN | ALTEN Subcontractor
pour ALCATEL-LUCENT | in ALCATEL-LUCENT

email: [email protected]

Thanh-Lam NGUYEN

author

2011-10-14 08:52 UTC #1 lore raw

Sorry for upping the patch,
as it is my first contribution I would like to know if there is any problem with it.

Best regard
Thanh lam NGUYEN

Quoted 116 lines · Thanh-Lam NGUYEN

Signed-off-by Thanh Lam NGUYEN <[email protected]>

Signed-off-by Benjamin ZORES <[email protected]>

---
 linux/fs/binfmt_elf.c |   54
++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 4 deletions(-)

fs/binfmt_elf.c +56 -3

@@ -1085,6 +1085,48 @@
  * Jeremy Fitzhardinge <[email protected]>
  */
 
+/*
+ * Search for 1st and last allocated page from vma_start to vma_end.
+ * Update vma_start and vma_end to reflect the result.
+ */
+void vma_shrink(struct vm_area_struct *vma, unsigned long *vma_start,
+		unsigned long *vma_end)
+{
+	int allocated;
+	unsigned long start, addr, end;
+
+	allocated = 0;
+	start = end = *vma_start;
+	for (addr = *vma_start; _addr < *vma_end; addr += PAGE_SIZE) {
+		struct page *page;
+		if (get_user_pages(current, current->mm, addr, 1, 0, 1,
+				   &page, NULL) <= 0) {
+			/* NO PAGE */
+			if (!allocated)
+				start = addr;
+		} else {
+			if (page == ZERO_PAGE(0)) {
+				/* ZERO PAGE */
+				if (!allocated)
+					start = addr;
+			} else {
+				/* ALLOCATED PAGE */
+				if (!allocated)
+					start = addr;
+				end = addr;
+				allocated = 1;
+			}
+			page_cache_release(page);
+		}
+	}
+	if (end < start)
+		end = start;
+	if (allocated)
+		end += PAGE_SIZE;
+	*vma_start = start;
+	*vma_end = end;
+}
+
 /*
  * Decide what to dump of a segment, part, all or none.
  */

@@ -1980,13 +2022,19 @@ static int elf_core_dump(struct coredump_params
 *cprm)
 	for (vma = first_vma(current, gate_vma); vma != NULL;
 			vma = next_vma(vma, gate_vma)) {
 		struct elf_phdr phdr;
+		unsigned long start = vma->vm_start;
+		unsigned long end = vma->vm_end;
  		phdr.p_type = PT_LOAD;
 		phdr.p_offset = offset;
-		phdr.p_vaddr = vma->vm_start;
 		phdr.p_paddr = 0;
 		phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags);
-		phdr.p_memsz = vma->vm_end - vma->vm_start;
+		if (phdr.p_filesz) {
+			vma_shrink(vma, &start, &end);
+			phdr.p_filesz = end-start;
+		}
+		phdr.p_vaddr = start;
+		phdr.p_memsz = vma->vm_end - phdr.p_vaddr;
 		offset += phdr.p_filesz;
 		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
 		if (vma->vm_flags & VM_WRITE)

@@ -2018,11 +2066,15 @@ static int elf_core_dump(struct coredump_params
 *cprm)
 	for (vma = first_vma(current, gate_vma); vma != NULL;
 			vma = next_vma(vma, gate_vma)) {
 		unsigned long addr;
+		unsigned long start;
 		unsigned long end;
 -		end = vma->vm_start + vma_dump_size(vma, cprm->mm_flags);
+		start = vma->vm_start;
+		end = start + vma_dump_size(vma, cprm->mm_flags);
+		if (start < end)
+			vma_shrink(vma, &start, &end);
 -		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
+		for (addr = start; addr < end; addr += PAGE_SIZE) {
 			struct page *page;
 			int stop;
 
---

=~=~=~=~=~=~=~=~=~=~=~=~==~=~=~=~=~=~=~=~=~=~=~=~=~=~=
Thanh lam NGUYEN
Prestataire externe ALTEN | ALTEN Subcontractor
pour ALCATEL-LUCENT | in ALCATEL-LUCENT

email: [email protected]

--
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Signature · 9 lines

=~=~=~=~=~=~=~=~=~=~=~=~==~=~=~=~=~=~=~=~=~=~=~=~=~=~=
Thanh lam NGUYEN
Prestataire externe ALTEN        | ALTEN Subcontractor
pour ALCATEL-LUCENT              | in ALCATEL-LUCENT

Tel: +333906 77095

Equipe/Team: SWINT
email: [email protected]

Hillf Danton

2011-10-14 14:45 UTC #2 lore raw

Quoted 4 lines · Thanh-Lam NGUYEN

Sorry for upping the patch,
as it is my first contribution I would like to know if there is any problem with it.

Quoted 15 lines

Best regard
Thanh lam NGUYEN
Quoted 10 lines · Thanh-Lam NGUYEN
The vma_shrink function looks for the 1st allocated and the last allocated page. Only this part is dumped to the disk (the virual start address and the size are dupdated to reflect the new dumped information).
Signed-off-by Thanh Lam NGUYEN <[email protected]>
Signed-off-by Benjamin ZORES <[email protected]>
---
linux/fs/binfmt_elf.c | 54
++++++++++++++++++++++++++++++++++++++++++++++----

corrupted message?

Quoted 8 lines

 1 file changed, 55 insertions(+), 4 deletions(-)

fs/binfmt_elf.c +0 -0

@@ -1085,6 +1085,48 @@
   * Jeremy Fitzhardinge <[email protected]>
   */

Quoted 13 lines

fs/binfmt_elf.c line 1100

Quoted 13 lines

fs/binfmt_elf.c +13 -0

+/*
+ * Search for 1st and last allocated page from vma_start to vma_end.
+ * Update vma_start and vma_end to reflect the result.
+ */
+void vma_shrink(struct vm_area_struct *vma, unsigned long *vma_start,
+             unsigned long *vma_end)
+{
+     int allocated;
+     unsigned long start, addr, end;
+
+     allocated = 0;
+     start = end = *vma_start;
+     for (addr = *vma_start; _addr < *vma_end; addr += PAGE_SIZE) {

-----^ where is _addr from?

Quoted 4 lines

fs/binfmt_elf.c +4 -0

+             struct page *page;
+             if (get_user_pages(current, current->mm, addr, 1, 0, 1,
+                                &page, NULL) <= 0) {
+                     /* NO PAGE */

Thanh-Lam NGUYEN

author

2011-10-14 15:04 UTC #3 lore raw

Quoted 32 lines · Hillf Danton

Quoted 4 lines · Thanh-Lam NGUYEN
Sorry for upping the patch,
as it is my first contribution I would like to know if there is any problem with it.
Quoted 15 lines
Best regard
Thanh lam NGUYEN
Quoted 10 lines · Thanh-Lam NGUYEN
The vma_shrink function looks for the 1st allocated and the last allocated page. Only this part is dumped to the disk (the virual start address and the size are dupdated to reflect the new dumped information).
Signed-off-by Thanh Lam NGUYEN <[email protected]>
Signed-off-by Benjamin ZORES <[email protected]>
---
 linux/fs/binfmt_elf.c |   54
++++++++++++++++++++++++++++++++++++++++++++++----
corrupted message?
Quoted 8 lines
Quoted 8 lines
 1 file changed, 55 insertions(+), 4 deletions(-)
fs/binfmt_elf.c +0 -0
@@ -1085,6 +1085,48 @@
  * Jeremy Fitzhardinge <[email protected]>
  */
 

Quoted 16 lines

Quoted 5 lines

fs/binfmt_elf.c +5 -0

+/*
+ * Search for 1st and last allocated page from vma_start to vma_end.
+ * Update vma_start and vma_end to reflect the result.
+ */
+void vma_shrink(struct vm_area_struct *vma, unsigned long *vma_start,

Quoted 8 lines

fs/binfmt_elf.c line 1100

Quoted 8 lines

fs/binfmt_elf.c +8 -0

+             unsigned long *vma_end)
+{
+     int allocated;
+     unsigned long start, addr, end;
+
+     allocated = 0;
+     start = end = *vma_start;
+     for (addr = *vma_start; _addr < *vma_end; addr += PAGE_SIZE) {

-----^ where is _addr from?

My bad, it's addr and not _addr.

Quoted 9 lines

Quoted 4 lines
fs/binfmt_elf.c line 1104
Quoted 4 lines
fs/binfmt_elf.c +4 -0
+             struct page *page;
+             if (get_user_pages(current, current->mm, addr, 1, 0, 1,
+                                &page, NULL) <= 0) {
+                     /* NO PAGE */
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Signature · 9 lines

=~=~=~=~=~=~=~=~=~=~=~=~==~=~=~=~=~=~=~=~=~=~=~=~=~=~=
Thanh lam NGUYEN
Prestataire externe ALTEN        | ALTEN Subcontractor
pour ALCATEL-LUCENT              | in ALCATEL-LUCENT

Tel: +333906 77095

Equipe/Team: SWINT
email: [email protected]

Thanh-Lam NGUYEN

author

2011-10-18 07:52 UTC #4 lore raw

In reply to Thanh-Lam NGUYEN

Here is the patch with the fix on the variable name.
To be sure that the mailer does not screw the patch, it is attached and not inlined.

Signature · 7 lines

=~=~=~=~=~=~=~=~=~=~=~=~==~=~=~=~=~=~=~=~=~=~=~=~=~=~=
Thanh lam NGUYEN
Prestataire externe ALTEN        | ALTEN Subcontractor
pour ALCATEL-LUCENT              | in ALCATEL-LUCENT

Equipe/Team: SWINT
email: [email protected]

The vma_shrink function looks for the 1st allocated and the last allocated page. Only this part is dumped to the disk (the virual start address and the size are updated to reflect the new dumped information).

Signed-off-by Thanh Lam NGUYEN <[email protected]>

Signed-off-by Benjamin ZORES <[email protected]>

---
 linux/fs/binfmt_elf.c |   54 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 55 insertions(+), 4 deletions(-)

fs/binfmt_elf.c +56 -4

@@ -1085,6 +1085,48 @@
  * Jeremy Fitzhardinge <[email protected]>
  */
 
+/*
+ * Search for 1st and last allocated page from vma_start to vma_end.
+ * Update vma_start and vma_end to reflect the result.
+ */
+void vma_shrink(struct vm_area_struct *vma, unsigned long *vma_start,
+		unsigned long *vma_end)
+{
+	int allocated;
+	unsigned long start, addr, end;
+
+	allocated = 0;
+	start = end = *vma_start;
+	for (addr = *vma_start; addr < *vma_end; addr += PAGE_SIZE) {
+		struct page *page;
+		if (get_user_pages(current, current->mm, addr, 1, 0, 1,
+				   &page, NULL) <= 0) {
+			/* NO PAGE */
+			if (!allocated)
+				start = addr;
+		} else {
+			if (page == ZERO_PAGE(0)) {
+				/* ZERO PAGE */
+				if (!allocated)
+					start = addr;
+			} else {
+				/* ALLOCATED PAGE */
+				if (!allocated)
+					start = addr;
+				end = addr;
+				allocated = 1;
+			}
+			page_cache_release(page);
+		}
+	}
+	if (end < start)
+		end = start;
+	if (allocated)
+		end += PAGE_SIZE;
+	*vma_start = start;
+	*vma_end = end;
+}
+
 /*
  * Decide what to dump of a segment, part, all or none.
  */

@@ -1980,13 +2022,19 @@ static int elf_core_dump(struct coredump_params *cprm)
 	for (vma = first_vma(current, gate_vma); vma != NULL;
 			vma = next_vma(vma, gate_vma)) {
 		struct elf_phdr phdr;
+		unsigned long start = vma->vm_start;
+		unsigned long end = vma->vm_end;
 
 		phdr.p_type = PT_LOAD;
 		phdr.p_offset = offset;
-		phdr.p_vaddr = vma->vm_start;
 		phdr.p_paddr = 0;
 		phdr.p_filesz = vma_dump_size(vma, cprm->mm_flags);
-		phdr.p_memsz = vma->vm_end - vma->vm_start;
+		if (phdr.p_filesz) {
+			vma_shrink(vma, &start, &end);
+			phdr.p_filesz = end-start;
+		}
+		phdr.p_vaddr = start;
+		phdr.p_memsz = vma->vm_end - phdr.p_vaddr;
 		offset += phdr.p_filesz;
 		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
 		if (vma->vm_flags & VM_WRITE)

@@ -2018,11 +2066,15 @@ static int elf_core_dump(struct coredump_params *cprm)
 	for (vma = first_vma(current, gate_vma); vma != NULL;
 			vma = next_vma(vma, gate_vma)) {
 		unsigned long addr;
+		unsigned long start;
 		unsigned long end;
 
-		end = vma->vm_start + vma_dump_size(vma, cprm->mm_flags);
+		start = vma->vm_start;
+		end = start + vma_dump_size(vma, cprm->mm_flags);
+		if (start < end)
+			vma_shrink(vma, &start, &end);
 
-		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
+		for (addr = start; addr < end; addr += PAGE_SIZE) {
 			struct page *page;
 			int stop;