diff -urP linux-2.5.4/fs/exec.c linux-2.5.4-patch/fs/exec.c
--- linux-2.5.4/fs/exec.c Sun Feb 10 20:50:15 2002
+++ linux-2.5.4-patch/fs/exec.c Thu Feb 14 12:45:00 2002
@@ -35,6 +35,7 @@
#include <linux/highmem.h>
#include <linux/spinlock.h>
#include <linux/personality.h>
+#include <linux/utsname.h>
#include <linux/binfmts.h>
#define __NO_VERSION__
#include <linux/module.h>
@@ -49,6 +50,12 @@
int core_uses_pid;
+/* The format string for the core file name...
+ We default to "core" such that past behavior
+ remains unchanged. The 64 character limit is
+ arbitrary but must match the sysctl table. */
+char core_name_format[64] = {"core"};
+
static struct linux_binfmt *formats;
static rwlock_t binfmt_lock = RW_LOCK_UNLOCKED;
@@ -934,14 +941,37 @@
__MOD_DEC_USE_COUNT(old->module);
}
+/* This is the maximum expanded core file name. We use
+ a reasonable number here since we use the stack to
+ do the expansion. However, the number should be big
+ enough to handle a reasonable command name plus PID
+ and/or UID in addition to the file name part that
+ is in the core_name_format string. */
+#define MAX_CORE_NAME (160)
+
int do_coredump(long signr, struct pt_regs * regs)
{
struct linux_binfmt * binfmt;
- char corename[6+sizeof(current->comm)+10];
struct file * file;
struct inode * inode;
int retval = 0;
+ int fmt_i;
+ int name_n;
+ int addPID;
+ char *cname;
+
+ /* The +11 is here to simplify the code path. What
+ we do is always check that we are less than MAX
+ but there are times when we also need to append
+ a number (such as the PID or UID). Rather than
+ using another temporary buffer, we provide for
+ enough extra space such that those numbers can
+ be added in one gulp even if we are just under
+ the MAX_CORE_NAME. Reduction in complexity of
+ the code path means a more reliable implementation. */
+ char corename[MAX_CORE_NAME + 1 + 11];
+
lock_kernel();
binfmt = current->binfmt;
if (!binfmt || !binfmt->core_dump)
@@ -952,10 +982,92 @@
if (current->rlim[RLIMIT_CORE].rlim_cur < binfmt->min_coredump)
goto fail;
- memcpy(corename,"core.", 5);
- corename[4] = '\0';
- if (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1)
- sprintf(&corename[4], ".%d", current->pid);
+ /* Set this to true if we are going to add the PID. If the PID
+ already is added in the format we will end up clearing this.
+ The purpose is to provide for the old behavior of adding the
+ PID to the core file name but to not add it if it already
+ was included via the file name format pattern. */
+ addPID = (core_uses_pid || atomic_read(¤t->mm->mm_users) != 1);
+
+ /* Build the core file name as needed from the format string */
+ for (fmt_i=0, name_n=0;
+ name_n < MAX_CORE_NAME && core_name_format[fmt_i];
+ fmt_i++)
+ {
+ switch (core_name_format[fmt_i])
+ {
+ case '%': /* A format character */
+ fmt_i++;
+ switch (core_name_format[fmt_i])
+ {
+ case '%': /* The way we get this character */
+ corename[name_n++] = '%';
+ break;
+
+ case 'N': /* Process name */
+ cname=current->comm;
+
+ /* Only copy as much as will fit within the
+ MAX_CORE_NAME */
+ while (*cname && (name_n < MAX_CORE_NAME))
+ {
+ if (*cname != '/')
+ corename[name_n++] = *cname;
+ cname++;
+ }
+ break;
+
+ case 'H': /* Node name */
+ cname=system_utsname.nodename;
+
+ /* Only copy as much as will fit within the
+ MAX_CORE_NAME */
+ while (*cname && (name_n < MAX_CORE_NAME))
+ {
+ if (*cname != '/')
+ corename[name_n++] = *cname;
+ cname++;
+ }
+ break;
+
+ case 'P': /* Process PID */
+ /* Since we are adding it here, don't append */
+ addPID=0;
+
+ /* We don't need to pre-check that the number
+ fits since we added a padding of 11
+ characters to the end of the string buffer
+ just so that we don't need to do an extra
+ check */
+ name_n += sprintf(&corename[name_n],"%d",current->pid);
+ break;
+
+ case 'U': /* UID of the process */
+ /* We don't need to pre-check that the number
+ fits since we added a padding of 11
+ characters to the end of the string buffer
+ just so that we don't need to do an extra
+ check */
+ name_n += sprintf(&corename[name_n],"%d",current->uid);
+ break;
+ }
+ break;
+
+ default: /* Anything else just pass along */
+ corename[name_n++] = core_name_format[fmt_i];
+ }
+ }
+
+ /* If we still want to append the PID and there is room, do so */
+ /* This is to preserve current behavior */
+ if (addPID && (name_n < MAX_CORE_NAME))
+ {
+ name_n += sprintf(&corename[name_n],".%d",current->pid);
+ }
+
+ /* And make sure to null terminate the string */
+ corename[name_n]='\0';
+
file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW, 0600);
if (IS_ERR(file))
goto fail;
diff -urP linux-2.5.4/include/linux/sysctl.h linux-2.5.4-patch/include/linux/sysctl.h
--- linux-2.5.4/include/linux/sysctl.h Sun Feb 10 20:50:07 2002
+++ linux-2.5.4-patch/include/linux/sysctl.h Thu Feb 14 12:43:52 2002
@@ -124,6 +124,7 @@
KERN_CORE_USES_PID=52, /* int: use core or core.%pid */
KERN_TAINTED=53, /* int: various kernel tainted flags */
KERN_CADPID=54, /* int: PID of the process to notify on CAD */
+ KERN_CORE_NAME_FORMAT=55, /* string: core file name format string */
};
diff -urP linux-2.5.4/kernel/sysctl.c linux-2.5.4-patch/kernel/sysctl.c
--- linux-2.5.4/kernel/sysctl.c Sun Feb 10 20:50:09 2002
+++ linux-2.5.4-patch/kernel/sysctl.c Thu Feb 14 12:43:52 2002
@@ -50,6 +50,7 @@
extern int max_queued_signals;
extern int sysrq_enabled;
extern int core_uses_pid;
+extern char core_name_format[];
extern int cad_pid;
/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
@@ -172,6 +173,8 @@
0644, NULL, &proc_dointvec},
{KERN_CORE_USES_PID, "core_uses_pid", &core_uses_pid, sizeof(int),
0644, NULL, &proc_dointvec},
+ {KERN_CORE_NAME_FORMAT, "core_name_format", core_name_format, 64,
+ 0644, NULL, &proc_doutsstring, &sysctl_string},
{KERN_TAINTED, "tainted", &tainted, sizeof(int),
0644, NULL, &proc_dointvec},
{KERN_CAP_BSET, "cap-bound", &cap_bset, sizeof(kernel_cap_t),
I don't know how this second posting showed up. Sorry about that.
--
Michael Sinz ---- Worldgate Communications ---- [email protected]
A master's secrets are only as good as
the master's ability to explain them to others.
Michael Sinz <[email protected]> said:
> I have, for a long time, wished that Linux had a way to specify where
> core dumps are stored
CWD (chdir(2))
> and what the name of the core dump is.
/proc/sys/kernel/core_uses_pid
--
Horst von Brand http://counter.li.org # 22616
Horst von Brand wrote:
>
> Michael Sinz <[email protected]> said:
> > I have, for a long time, wished that Linux had a way to specify where
> > core dumps are stored
>
> CWD (chdir(2))
So, all of my applications and support programs should run with their
CWD set to /coredumps? I don't want to flame here, but "get real".
That is almost as good as saying that to get security you just need to
make sure no one bad is using your system.
> > and what the name of the core dump is.
>
> /proc/sys/kernel/core_uses_pid
Well, this does make unique file names, almost. But it does not really
identify the file. Plus, in a cluster of machines, many of them have
the same PIDs. (Say, 100 machines, you get 100 of each PID)
--
Michael Sinz ---- Blackdown Java -- http://www.sinz.org/Michael.Sinz
Michael Sinz ---- Worldgate Communications ---- [email protected]
A master's secrets are only as good as
the master's ability to explain them to others.