* [PATCH] linux-2.6.16.51 gzipped core dump patch
@ 2007-09-04 0:49 Pallewatta Mano-FPCD67
2007-09-04 1:38 ` Al Viro
0 siblings, 1 reply; 6+ messages in thread
From: Pallewatta Mano-FPCD67 @ 2007-09-04 0:49 UTC (permalink / raw)
To: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 429 bytes --]
Hi,
The attached patch is based on Jan Frey's previous patch posted in 2004
for the Linux 2.4 kernel. It has been tested on X86 and MIPS platforms.
If the core pattern doesn't end in ".gz" it will be added to the name of
the core file. It's offered under GPL v2 without any warranties. If you
have any questions, please contact me directly at Mano.Pallewatta "at"
motorola.com.
Regards,
Methlal (Mano) Pallewatta
[-- Attachment #2: gzipped_core_dump.patch --]
[-- Type: application/octet-stream, Size: 16713 bytes --]
--- linux-2.6.16.51/fs/binfmt_elf.c 2007-07-30 18:31:50.000000000 -0700
+++ linux-2.6.16.51/fs/binfmt_elf.c 2007-07-31 00:38:18.000000000 -0700
@@ -9,6 +9,7 @@
* Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
*/
+#include <linux/config.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
@@ -60,6 +61,20 @@
*/
#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
static int elf_core_dump(long signr, struct pt_regs * regs, struct file * file);
+
+#ifdef CONFIG_GZIP_COREDUMPS
+
+/*
+ * Functions added to support writing core files in gzipped format, 2004
+ * Jan Frey <jan.frey@nokia.com>
+ * Mano Pallewatta <Mano.Pallewatta@motorola.com>
+ */
+#include <linux/zlib.h>
+#include <linux/vmalloc.h>
+#include <linux/crc32.h>
+#endif
+
+
#else
#define elf_core_dump NULL
#endif
@@ -1122,18 +1137,67 @@
/*
* ELF core dumper
*
- * Modelled on fs/exec.c:aout_core_dump()
- * Jeremy Fitzhardinge <jeremy@sw.oz.au>
- */
-/*
- * These are the only things you should do on a core-file: use only these
- * functions to write out all the necessary info.
+ * gz writing support
+ * Jan Frey <jan.frey@nokia.com>
+ * Mano Pallewatta <Mano.Pallewatta@motorola.com>
*/
-static int dump_write(struct file *file, const void *addr, int nr)
+#ifdef CONFIG_GZIP_COREDUMPS
+
+#define OUT_BUF_SIZE 100*1024
+
+static int gz_dump_write(struct file *file, const void *addr, int nr, u32 *crc, z_streamp zstr, void *out_buf)
{
- return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+ int all_fine = 1;
+
+ *crc = crc32_le (*crc, addr, nr);
+
+ zstr->next_in = (void *)addr;
+ zstr->avail_in = nr;
+
+ do {
+ zstr->next_out = out_buf;
+ zstr->avail_out = OUT_BUF_SIZE;
+
+ if (zlib_deflate (zstr, Z_NO_FLUSH) == Z_OK) {
+ /* new output generated */
+ all_fine = (file->f_op->write (file,
+ out_buf,
+ OUT_BUF_SIZE - zstr->avail_out,
+ &file->f_pos)
+ == (OUT_BUF_SIZE - zstr->avail_out));
+ }
+ } while ((zstr->avail_out != OUT_BUF_SIZE) && all_fine);
+
+ return all_fine;
}
+static int gz_finish (struct file *file, z_streamp zstr, void *out_buf)
+{
+ int all_fine = 1;
+ int ret;
+
+ zstr->next_in = 0;
+ zstr->avail_in = 0;
+
+ do {
+ zstr->next_out = out_buf;
+ zstr->avail_out = OUT_BUF_SIZE;
+
+ ret = zlib_deflate (zstr, Z_FINISH);
+ if ((ret == Z_OK) || (ret == Z_STREAM_END)) {
+ /* new output generated */
+ all_fine = (file->f_op->write (file,
+ out_buf,
+ OUT_BUF_SIZE - zstr->avail_out,
+ &file->f_pos)
+ == (OUT_BUF_SIZE - zstr->avail_out));
+ }
+ } while ((zstr->avail_out != OUT_BUF_SIZE) && all_fine && (ret != Z_STREAM_END));
+
+ return all_fine;
+}
+
+#else
static int dump_seek(struct file *file, loff_t off)
{
if (file->f_op->llseek) {
@@ -1143,6 +1207,15 @@
file->f_pos = off;
return 1;
}
+#endif
+/*
+ * These are the only things you should do on a core-file: use only these
+ * functions to write out all the necessary info.
+ */
+static int dump_write(struct file *file, const void *addr, int nr)
+{
+ return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+}
/*
* Decide whether a segment is worth dumping; default is yes to be
@@ -1189,12 +1262,55 @@
return sz;
}
+#ifdef CONFIG_GZIP_COREDUMPS
+#define PAD_GZ(nr, buf, crc, str, out_buf) \
+ do { \
+ int cur=(nr); \
+ while (cur>1024) { \
+ gz_dump_write(file, (buf), 1024, (crc), (str), (out_buf)); \
+ cur-=1024; \
+ } \
+ if (cur) { \
+ gz_dump_write(file, (buf), cur, (crc), (str), (out_buf)); \
+ } \
+ } while(0)
-#define DUMP_WRITE(addr, nr) \
- do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
+#define DUMP_GZ(addr, nr, crc, str, out_buf) \
+ do { if (!gz_dump_write(file, (addr), (nr), (crc), (str), (out_buf))) return 0; } while(0)
+
+#else
#define DUMP_SEEK(off) \
do { if (!dump_seek(file, (off))) return 0; } while(0)
+#endif
+
+#define DUMP_WRITE(addr, nr) \
+ do { if (!dump_write(file, (addr), (nr))) return 0; } while(0)
+
+#ifdef CONFIG_GZIP_COREDUMPS
+static int writenote_gz(struct memelfnote *men, struct file *file, char *buf, u32 *crc, z_streamp zstr, void *out_buf)
+{
+ struct elf_note en;
+ int dummy_bytes;
+
+ en.n_namesz = strlen(men->name)+1;
+ en.n_descsz = men->datasz;
+ en.n_type = men->type;
+
+ DUMP_GZ(&en, sizeof(en), crc, zstr, out_buf);
+ DUMP_GZ(men->name, en.n_namesz, crc, zstr, out_buf);
+
+ dummy_bytes = roundup((unsigned long)zstr->total_in, 4) - zstr->total_in;
+ PAD_GZ(dummy_bytes, buf, crc, zstr, out_buf);
+
+ DUMP_GZ(men->data, men->datasz, crc, zstr, out_buf);
+
+ dummy_bytes = roundup((unsigned long)zstr->total_in, 4) - zstr->total_in;
+ PAD_GZ(dummy_bytes, buf, crc, zstr, out_buf);
+ return 1;
+}
+#undef DUMP_GZ
+#else
static int writenote(struct memelfnote *men, struct file *file)
{
struct elf_note en;
@@ -1214,13 +1330,20 @@
}
#undef DUMP_WRITE
#undef DUMP_SEEK
+#endif
+#ifdef CONFIG_GZIP_COREDUMPS
+#define DUMP_GZ(addr, nr, crc, str, out_buf) \
+ if ((size += (nr)) > limit || !gz_dump_write(file, (addr), (nr), (crc), (str), (out_buf))) \
+ goto end_coredump;
+#else
#define DUMP_WRITE(addr, nr) \
if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
goto end_coredump;
#define DUMP_SEEK(off) \
if (!dump_seek(file, (off))) \
goto end_coredump;
+#endif
static void fill_elf_header(struct elfhdr *elf, int segs)
{
@@ -1424,6 +1547,52 @@
#endif
int thread_status_size = 0;
elf_addr_t *auxv;
+#ifdef CONFIG_GZIP_COREDUMPS
+ z_stream gz_stream;
+ void *deflate_workspace;
+ u32 crc = ~0; /* init */
+ unsigned char gz_magic[10] = { /* gzip magic header */
+ 0x1f, 0x8b, Z_DEFLATED, 0, 0, 0, 0, 0, 0, 0x03 };
+ void *out_buf = NULL;
+ void *empty_buf = NULL;
+
+ out_buf = vmalloc(OUT_BUF_SIZE);
+ if (!out_buf) {
+ printk(KERN_WARNING "Failed to allocate deflate buffer");
+ return -ENOMEM;
+ }
+
+ empty_buf = vmalloc(1024);
+ if (!empty_buf) {
+ vfree(out_buf);
+ printk(KERN_WARNING "Failed to allocate memory for dummy buffer\n");
+ return -ENOMEM;
+ }
+
+ deflate_workspace = vmalloc(zlib_deflate_workspacesize());
+ if (!deflate_workspace) {
+ vfree(out_buf);
+ vfree(empty_buf);
+ printk(KERN_WARNING "Failed to allocate deflate workspace\n");
+ return -ENOMEM;
+ }
+
+ gz_stream.workspace = deflate_workspace;
+ if (Z_OK != zlib_deflateInit2(&gz_stream,
+ 7, /* compression level */
+ Z_DEFLATED,
+ -15, /* window bits */
+ 6, /* mem level */
+ Z_DEFAULT_STRATEGY)) {
+ printk(KERN_WARNING "deflateInit failed\n");
+ vfree(out_buf);
+ vfree(empty_buf);
+ vfree(deflate_workspace);
+ return -ENOMEM;
+ }
+
+ memset (empty_buf, 0, 1024);
+#endif
/*
* We no longer stop all VM operations.
@@ -1535,7 +1704,15 @@
fs = get_fs();
set_fs(KERNEL_DS);
+#ifdef CONFIG_GZIP_COREDUMPS
+ /* write gzip header */
+ DUMP_WRITE(gz_magic, 10);
+
+ /* write elf header */
+ DUMP_GZ(elf, sizeof(*elf), &crc, &gz_stream, out_buf);
+#else
DUMP_WRITE(elf, sizeof(*elf));
+#endif
offset += sizeof(*elf); /* Elf header */
offset += (segs+1) * sizeof(struct elf_phdr); /* Program headers */
@@ -1551,7 +1728,12 @@
fill_elf_note_phdr(&phdr, sz, offset);
offset += sz;
+
+#ifdef CONFIG_GZIP_COREDUMPS
+ DUMP_GZ(&phdr, sizeof(phdr), &crc, &gz_stream, out_buf);
+#else
DUMP_WRITE(&phdr, sizeof(phdr));
+#endif
}
/* Page-align dumped data */
@@ -1576,7 +1758,11 @@
if (vma->vm_flags & VM_EXEC) phdr.p_flags |= PF_X;
phdr.p_align = ELF_EXEC_PAGESIZE;
+#ifdef CONFIG_GZIP_COREDUMPS
+ DUMP_GZ(&phdr, sizeof(phdr), &crc, &gz_stream, out_buf);
+#else
DUMP_WRITE(&phdr, sizeof(phdr));
+#endif
}
#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
@@ -1585,18 +1771,30 @@
/* write out the notes section */
for (i = 0; i < numnote; i++)
+#ifdef CONFIG_GZIP_COREDUMPS
+ if (!writenote_gz(notes + i, file, empty_buf, &crc, &gz_stream, out_buf))
+#else
if (!writenote(notes + i, file))
+#endif
goto end_coredump;
/* write out the thread status notes section */
list_for_each(t, &thread_list) {
struct elf_thread_status *tmp = list_entry(t, struct elf_thread_status, list);
for (i = 0; i < tmp->num_notes; i++)
+#ifdef CONFIG_GZIP_COREDUMPS
+ if (!writenote_gz(&tmp->notes[i], file, empty_buf, &crc, &gz_stream, out_buf))
+#else
if (!writenote(&tmp->notes[i], file))
+#endif
goto end_coredump;
}
+#ifdef CONFIG_GZIP_COREDUMPS
+ PAD_GZ (dataoff-gz_stream.total_in, empty_buf, &crc, &gz_stream, out_buf);
+#else
DUMP_SEEK(dataoff);
+#endif
for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
unsigned long addr;
@@ -1612,17 +1810,30 @@
if (get_user_pages(current, current->mm, addr, 1, 0, 1,
&page, &vma) <= 0) {
+#ifdef CONFIG_GZIP_COREDUMPS
+ PAD_GZ(PAGE_SIZE, empty_buf, &crc, &gz_stream, out_buf);
+#else
DUMP_SEEK (file->f_pos + PAGE_SIZE);
+#endif
} else {
if (page == ZERO_PAGE(addr)) {
- DUMP_SEEK (file->f_pos + PAGE_SIZE);
+#ifdef CONFIG_GZIP_COREDUMPS
+ PAD_GZ(PAGE_SIZE, empty_buf, &crc, &gz_stream, out_buf);
+#else
+ DUMP_SEEK (file->f_pos + PAGE_SIZE);
+#endif
} else {
void *kaddr;
flush_cache_page(vma, addr, page_to_pfn(page));
kaddr = kmap(page);
if ((size += PAGE_SIZE) > limit ||
+#ifdef CONFIG_GZIP_COREDUMPS
+ !gz_dump_write(file, kaddr,
+ PAGE_SIZE, &crc, &gz_stream, out_buf)) {
+#else
!dump_write(file, kaddr,
PAGE_SIZE)) {
+#endif
kunmap(page);
page_cache_release(page);
goto end_coredump;
@@ -1638,13 +1849,29 @@
ELF_CORE_WRITE_EXTRA_DATA;
#endif
+#ifndef CONFIG_GZIP_COREDUMPS
if ((off_t)file->f_pos != offset) {
/* Sanity check */
printk(KERN_WARNING "elf_core_dump: file->f_pos (%ld) != offset (%ld)\n",
(off_t)file->f_pos, offset);
}
+#endif
end_coredump:
+#ifdef CONFIG_GZIP_COREDUMPS
+ gz_finish (file, &gz_stream, out_buf);
+ zlib_deflateEnd (&gz_stream);
+
+ gz_magic[0] = (~crc & 0x000000FF);
+ gz_magic[1] = (~crc & 0x0000FF00) >> 8;
+ gz_magic[2] = (~crc & 0x00FF0000) >> 16;
+ gz_magic[3] = (~crc & 0xFF000000) >> 24;
+ gz_magic[4] = (gz_stream.total_in & 0x000000FF);
+ gz_magic[5] = (gz_stream.total_in & 0x0000FF00) >> 8;
+ gz_magic[6] = (gz_stream.total_in & 0x00FF0000) >> 16;
+ gz_magic[7] = (gz_stream.total_in & 0xFF000000) >> 24;
+ dump_write (file, gz_magic, 8);
+ #endif
set_fs(fs);
cleanup:
@@ -1662,6 +1889,12 @@
#ifdef ELF_CORE_COPY_XFPREGS
kfree(xfpu);
#endif
+
+#ifdef CONFIG_GZIP_COREDUMPS
+ vfree (deflate_workspace);
+ vfree (empty_buf);
+ vfree (out_buf);
+#endif
return has_dumped;
#undef NUM_NOTES
}
--- linux-2.6.16.51/fs/exec.c 2007-07-30 18:31:51.000000000 -0700
+++ linux-2.6.16.51/fs/exec.c 2007-07-31 00:25:05.000000000 -0700
@@ -1366,6 +1366,15 @@
out_ptr += rc;
}
out:
+#ifdef CONFIG_GZIP_COREDUMPS
+ if (strncmp(out_ptr-3,".gz",3)) {
+ rc = snprintf(out_ptr, out_end - out_ptr,"%s",".gz");
+ if (rc > out_end - out_ptr)
+ goto out1;
+ out_ptr += rc;
+ }
+#endif
+ out1:
*out_ptr = 0;
}
--- linux-2.6.16.51/fs/Kconfig 2007-07-30 18:31:50.000000000 -0700
+++ linux-2.6.16.51/fs/Kconfig 2007-07-31 00:25:05.000000000 -0700
@@ -802,6 +802,12 @@
help
Exports the dump image of crashed kernel in ELF format.
+config GZIP_COREDUMPS
+ bool "Write gzipped core dump files"
+ default n
+ select ZLIB_DEFLATE
+ select CRC32
+
config SYSFS
bool "sysfs file system support" if EMBEDDED
default y
--- linux-2.6.16.51/include/asm-i386/elf.h 2007-08-15 00:59:49.000000000 -0700
+++ linux-2.6.16.51/include/asm-i386/elf.h 2007-08-15 09:39:12.000000000 -0700
@@ -149,6 +149,8 @@
* a debugger needs to easily find how the vsyscall DSO was being used.
*/
#define ELF_CORE_EXTRA_PHDRS (VSYSCALL_EHDR->e_phnum)
+
+#ifdef CONFIG_GZIP_COREDUMPS
#define ELF_CORE_WRITE_EXTRA_PHDRS \
do { \
const struct elf_phdr *const vsyscall_phdrs = \
@@ -168,9 +170,49 @@
else \
phdr.p_offset += ofs; \
phdr.p_paddr = 0; /* match other core phdrs */ \
- DUMP_WRITE(&phdr, sizeof(phdr)); \
+ DUMP_GZ(&phdr, sizeof(phdr), &crc, &gz_stream, out_buf); \
} \
} while (0)
+#else
+#define ELF_CORE_WRITE_EXTRA_PHDRS \
+do { \
+ const struct elf_phdr *const vsyscall_phdrs = \
+ (const struct elf_phdr *) (VSYSCALL_BASE \
+ + VSYSCALL_EHDR->e_phoff); \
+ int i; \
+ Elf32_Off ofs = 0; \
+ for (i = 0; i < VSYSCALL_EHDR->e_phnum; ++i) { \
+ struct elf_phdr phdr = vsyscall_phdrs[i]; \
+ if (phdr.p_type == PT_LOAD) { \
+ BUG_ON(ofs != 0); \
+ ofs = phdr.p_offset = offset; \
+ phdr.p_memsz = PAGE_ALIGN(phdr.p_memsz); \
+ phdr.p_filesz = phdr.p_memsz; \
+ offset += phdr.p_filesz; \
+ } \
+ else \
+ phdr.p_offset += ofs; \
+ phdr.p_paddr = 0; /* match other core phdrs */ \
+ DUMP_WRITE(&phdr, sizeof(phdr)); \
+ } \
+} while (0)
+#endif
+
+#ifdef CONFIG_GZIP_COREDUMPS
+#define ELF_CORE_WRITE_EXTRA_DATA \
+do { \
+ const struct elf_phdr *const vsyscall_phdrs = \
+ (const struct elf_phdr *) (VSYSCALL_BASE \
+ + VSYSCALL_EHDR->e_phoff); \
+ int i; \
+ for (i = 0; i < VSYSCALL_EHDR->e_phnum; ++i) { \
+ if (vsyscall_phdrs[i].p_type == PT_LOAD) \
+ DUMP_GZ((void *) vsyscall_phdrs[i].p_vaddr, \
+ PAGE_ALIGN(vsyscall_phdrs[i].p_memsz), \
+ &crc, &gz_stream, out_buf); \
+ } \
+} while (0)
+#else
#define ELF_CORE_WRITE_EXTRA_DATA \
do { \
const struct elf_phdr *const vsyscall_phdrs = \
@@ -183,6 +225,7 @@
PAGE_ALIGN(vsyscall_phdrs[i].p_memsz)); \
} \
} while (0)
+#endif
#endif
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] linux-2.6.16.51 gzipped core dump patch
2007-09-04 0:49 [PATCH] linux-2.6.16.51 gzipped core dump patch Pallewatta Mano-FPCD67
@ 2007-09-04 1:38 ` Al Viro
2007-09-04 2:32 ` Pallewatta Mano-FPCD67
0 siblings, 1 reply; 6+ messages in thread
From: Al Viro @ 2007-09-04 1:38 UTC (permalink / raw)
To: Pallewatta Mano-FPCD67; +Cc: linux-kernel
On Mon, Sep 03, 2007 at 08:49:00PM -0400, Pallewatta Mano-FPCD67 wrote:
> Hi,
> The attached patch is based on Jan Frey's previous patch posted in 2004
> for the Linux 2.4 kernel. It has been tested on X86 and MIPS platforms.
> If the core pattern doesn't end in ".gz" it will be added to the name of
> the core file. It's offered under GPL v2 without any warranties. If you
> have any questions, please contact me directly at Mano.Pallewatta "at"
> motorola.com.
This is silly, IMO - why do in kernel what can be done in userland? External
process can damn well gzip/bzip2/uuencode and post to alt.sex.cthulhu.binaries/
whatever. Just feed the usual data to its stdin...
^ permalink raw reply [flat|nested] 6+ messages in thread
* RE: [PATCH] linux-2.6.16.51 gzipped core dump patch
2007-09-04 1:38 ` Al Viro
@ 2007-09-04 2:32 ` Pallewatta Mano-FPCD67
2007-09-04 3:26 ` Al Viro
0 siblings, 1 reply; 6+ messages in thread
From: Pallewatta Mano-FPCD67 @ 2007-09-04 2:32 UTC (permalink / raw)
To: Al Viro; +Cc: linux-kernel
This patch was developed for embedded systems which had limited space
for file storage. If an external process is to compress core files you
will need to store those files somewhere first as core dump output
cannot be directly fed to the stdin of compression program. Imagine
storing a 40 Meg core file in an embedded system. A few core files will
fill up the file system and some core files can get corrupted too.
Mano
-----Original Message-----
From: Al Viro [mailto:viro@ftp.linux.org.uk]
Sent: Monday, September 03, 2007 6:38 PM
To: Pallewatta Mano-FPCD67
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] linux-2.6.16.51 gzipped core dump patch
On Mon, Sep 03, 2007 at 08:49:00PM -0400, Pallewatta Mano-FPCD67 wrote:
> Hi,
> The attached patch is based on Jan Frey's previous patch posted in
2004
> for the Linux 2.4 kernel. It has been tested on X86 and MIPS
platforms.
> If the core pattern doesn't end in ".gz" it will be added to the name
of
> the core file. It's offered under GPL v2 without any warranties. If
you
> have any questions, please contact me directly at Mano.Pallewatta "at"
> motorola.com.
This is silly, IMO - why do in kernel what can be done in userland?
External
process can damn well gzip/bzip2/uuencode and post to
alt.sex.cthulhu.binaries/
whatever. Just feed the usual data to its stdin...
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] linux-2.6.16.51 gzipped core dump patch
2007-09-04 2:32 ` Pallewatta Mano-FPCD67
@ 2007-09-04 3:26 ` Al Viro
2007-09-04 4:04 ` Pallewatta Mano-FPCD67
0 siblings, 1 reply; 6+ messages in thread
From: Al Viro @ 2007-09-04 3:26 UTC (permalink / raw)
To: Pallewatta Mano-FPCD67; +Cc: linux-kernel
On Mon, Sep 03, 2007 at 10:32:00PM -0400, Pallewatta Mano-FPCD67 wrote:
> This patch was developed for embedded systems which had limited space
> for file storage. If an external process is to compress core files you
> will need to store those files somewhere first as core dump output
> cannot be directly fed to the stdin of compression program.
Why? Create a pipe, start a new process, put the reader struct file
into its descriptor table as stdin, do execve in new process and
pass the writer struct file to ->core_dump().
As the matter of fact, it's already done - see
lock_kernel();
ispipe = format_corename(corename, core_pattern, signr);
unlock_kernel();
if (ispipe) {
/* SIGPIPE can happen, but it's just never processed */
if(call_usermodehelper_pipe(corename+1, NULL, NULL, &file)) {
printk(KERN_INFO "Core dump to %s pipe failed\n",
corename);
goto fail_unlock;
}
} else
file = filp_open(corename,
O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
0600);
in do_coredump(). So take a look at fs/exec.c:format_corename() and see
what to feed for it in order to get the equivalent of your patch.
core_patttern is set by sysctl (just say
echo [whatever] >/proc/sys/kernel/core_pattern
and don't forget quoting, since | should be the first character to indicate
that you want to pipe coredump through a helper).
I really don't see a reason to do that kind of work in the kernel, embedded
system or not.
^ permalink raw reply [flat|nested] 6+ messages in thread* RE: [PATCH] linux-2.6.16.51 gzipped core dump patch
2007-09-04 3:26 ` Al Viro
@ 2007-09-04 4:04 ` Pallewatta Mano-FPCD67
2007-09-04 4:12 ` Al Viro
0 siblings, 1 reply; 6+ messages in thread
From: Pallewatta Mano-FPCD67 @ 2007-09-04 4:04 UTC (permalink / raw)
To: Al Viro; +Cc: linux-kernel
This support was there in the 2.6.16.51 kernel. In fact there was no
call_usermodehelper_pipe().
Mano
-----Original Message-----
From: Al Viro [mailto:viro@ftp.linux.org.uk]
Sent: Monday, September 03, 2007 8:27 PM
To: Pallewatta Mano-FPCD67
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] linux-2.6.16.51 gzipped core dump patch
On Mon, Sep 03, 2007 at 10:32:00PM -0400, Pallewatta Mano-FPCD67 wrote:
> This patch was developed for embedded systems which had limited space
> for file storage. If an external process is to compress core files you
> will need to store those files somewhere first as core dump output
> cannot be directly fed to the stdin of compression program.
Why? Create a pipe, start a new process, put the reader struct file
into its descriptor table as stdin, do execve in new process and
pass the writer struct file to ->core_dump().
As the matter of fact, it's already done - see
lock_kernel();
ispipe = format_corename(corename, core_pattern, signr);
unlock_kernel();
if (ispipe) {
/* SIGPIPE can happen, but it's just never processed */
if(call_usermodehelper_pipe(corename+1, NULL, NULL,
&file)) {
printk(KERN_INFO "Core dump to %s pipe
failed\n",
corename);
goto fail_unlock;
}
} else
file = filp_open(corename,
O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE
| flag,
0600);
in do_coredump(). So take a look at fs/exec.c:format_corename() and see
what to feed for it in order to get the equivalent of your patch.
core_patttern is set by sysctl (just say
echo [whatever] >/proc/sys/kernel/core_pattern
and don't forget quoting, since | should be the first character to
indicate
that you want to pipe coredump through a helper).
I really don't see a reason to do that kind of work in the kernel,
embedded
system or not.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2007-09-04 4:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2007-09-04 0:49 [PATCH] linux-2.6.16.51 gzipped core dump patch Pallewatta Mano-FPCD67
2007-09-04 1:38 ` Al Viro
2007-09-04 2:32 ` Pallewatta Mano-FPCD67
2007-09-04 3:26 ` Al Viro
2007-09-04 4:04 ` Pallewatta Mano-FPCD67
2007-09-04 4:12 ` Al Viro
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