[patch 7/8] process filtering for fault-injection capabilities
From: Akinobu Mita
Date: Thu Sep 14 2006 - 06:22:41 EST
This patch provides process filtering feature.
The process filter allows failing only permitted processes
by /proc/<pid>/make-it-fail
Please see the example that demostrates how to inject slab allocation
failures into module init/cleanup code
in Documentation/fault-injection/fault-injection.txt
Signed-off-by: Akinobu Mita <mita@xxxxxxxxxxxxxxxx>
fs/proc/base.c | 77 +++++++++++++++++++++++++++++++++++++++++++
include/linux/fault-inject.h | 3 +
include/linux/sched.h | 3 +
lib/fault-inject.c | 13 +++++++
4 files changed, 96 insertions(+)
Index: work-shouldfail/fs/proc/base.c
===================================================================
--- work-shouldfail.orig/fs/proc/base.c
+++ work-shouldfail/fs/proc/base.c
@@ -138,6 +138,9 @@ enum pid_directory_inos {
#endif
PROC_TGID_OOM_SCORE,
PROC_TGID_OOM_ADJUST,
+#ifdef CONFIG_FAULT_INJECTION
+ PROC_TGID_FAULT_INJECTION,
+#endif
PROC_TID_INO,
PROC_TID_STATUS,
PROC_TID_MEM,
@@ -181,6 +184,9 @@ enum pid_directory_inos {
#endif
PROC_TID_OOM_SCORE,
PROC_TID_OOM_ADJUST,
+#ifdef CONFIG_FAULT_INJECTION
+ PROC_TID_FAULT_INJECTION,
+#endif
/* Add new entries before this */
PROC_TID_FD_DIR = 0x8000, /* 0x8000-0xffff */
@@ -240,6 +246,9 @@ static struct pid_entry tgid_base_stuff[
#ifdef CONFIG_AUDITSYSCALL
E(PROC_TGID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
+#ifdef CONFIG_FAULT_INJECTION
+ E(PROC_TGID_FAULT_INJECTION, "make-it-fail", S_IFREG|S_IWUSR|S_IRUGO),
+#endif
{0,0,NULL,0}
};
static struct pid_entry tid_base_stuff[] = {
@@ -282,6 +291,9 @@ static struct pid_entry tid_base_stuff[]
#ifdef CONFIG_AUDITSYSCALL
E(PROC_TID_LOGINUID, "loginuid", S_IFREG|S_IWUSR|S_IRUGO),
#endif
+#ifdef CONFIG_FAULT_INJECTION
+ E(PROC_TID_FAULT_INJECTION, "make-it-fail", S_IFREG|S_IWUSR|S_IRUGO),
+#endif
{0,0,NULL,0}
};
@@ -992,6 +1004,65 @@ static struct file_operations proc_login
};
#endif
+#ifdef CONFIG_FAULT_INJECTION
+static ssize_t proc_fault_inject_read(struct file * file, char __user * buf,
+ size_t count, loff_t *ppos)
+{
+ struct task_struct *task = get_proc_task(file->f_dentry->d_inode);
+ char buffer[PROC_NUMBUF];
+ size_t len;
+ int make_it_fail;
+ loff_t __ppos = *ppos;
+
+ if (!task)
+ return -ESRCH;
+ make_it_fail = task->make_it_fail;
+ put_task_struct(task);
+
+ len = snprintf(buffer, sizeof(buffer), "%i\n", make_it_fail);
+ if (__ppos >= len)
+ return 0;
+ if (count > len-__ppos)
+ count = len-__ppos;
+ if (copy_to_user(buf, buffer + __ppos, count))
+ return -EFAULT;
+ *ppos = __ppos + count;
+ return count;
+}
+
+static ssize_t proc_fault_inject_write(struct file * file,
+ const char __user * buf, size_t count, loff_t *ppos)
+{
+ struct task_struct *task;
+ char buffer[PROC_NUMBUF], *end;
+ int make_it_fail;
+
+ if (!capable(CAP_SYS_RESOURCE))
+ return -EPERM;
+ memset(buffer, 0, sizeof(buffer));
+ if (count > sizeof(buffer) - 1)
+ count = sizeof(buffer) - 1;
+ if (copy_from_user(buffer, buf, count))
+ return -EFAULT;
+ make_it_fail = simple_strtol(buffer, &end, 0);
+ if (*end == '\n')
+ end++;
+ task = get_proc_task(file->f_dentry->d_inode);
+ if (!task)
+ return -ESRCH;
+ task->make_it_fail = make_it_fail;
+ put_task_struct(task);
+ if (end - buffer == 0)
+ return -EIO;
+ return end - buffer;
+}
+
+static struct file_operations proc_fault_inject_operations = {
+ .read = proc_fault_inject_read,
+ .write = proc_fault_inject_write,
+};
+#endif
+
#ifdef CONFIG_SECCOMP
static ssize_t seccomp_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
@@ -1834,6 +1905,12 @@ static struct dentry *proc_pident_lookup
inode->i_fop = &proc_loginuid_operations;
break;
#endif
+#ifdef CONFIG_FAULT_INJECTION
+ case PROC_TID_FAULT_INJECTION:
+ case PROC_TGID_FAULT_INJECTION:
+ inode->i_fop = &proc_fault_inject_operations;
+ break;
+#endif
default:
printk("procfs: impossible type (%d)",p->type);
iput(inode);
Index: work-shouldfail/include/linux/sched.h
===================================================================
--- work-shouldfail.orig/include/linux/sched.h
+++ work-shouldfail/include/linux/sched.h
@@ -996,6 +996,9 @@ struct task_struct {
#ifdef CONFIG_TASK_DELAY_ACCT
struct task_delay_info *delays;
#endif
+#ifdef CONFIG_FAULT_INJECTION
+ int make_it_fail;
+#endif
};
static inline pid_t process_group(struct task_struct *tsk)
Index: work-shouldfail/include/linux/fault-inject.h
===================================================================
--- work-shouldfail.orig/include/linux/fault-inject.h
+++ work-shouldfail/include/linux/fault-inject.h
@@ -27,6 +27,9 @@ struct fault_attr {
atomic_t space;
unsigned long count;
+
+ /* A value of '0' means process filter is disabled. */
+ u32 process_filter;
};
#define DEFINE_FAULT_ATTR(name) \
Index: work-shouldfail/lib/fault-inject.c
===================================================================
--- work-shouldfail.orig/lib/fault-inject.c
+++ work-shouldfail/lib/fault-inject.c
@@ -5,6 +5,7 @@
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/module.h>
+#include <linux/interrupt.h>
#include <linux/fault-inject.h>
int setup_fault_attr(struct fault_attr *attr, char *str)
@@ -49,6 +50,15 @@ void should_fail_srandom(unsigned long e
should_fail_random();
}
+static int fail_process(struct fault_attr *attr, struct task_struct *task)
+{
+ /* process filter is disabled */
+ if (!attr->process_filter)
+ return 1;
+
+ return !in_interrupt() && task->make_it_fail;
+}
+
/*
* This code is stolen from failmalloc-1.0
* http://www.nongnu.org/failmalloc/
@@ -56,6 +66,9 @@ void should_fail_srandom(unsigned long e
int should_fail(struct fault_attr *attr, ssize_t size)
{
+ if (!fail_process(attr, current))
+ return 0;
+
if (atomic_read(&max_failures(attr)) == 0)
return 0;
--
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/