[Devel] [PATCH 2/3] define function to print error messages to user log
Serge E. Hallyn
serue at us.ibm.com
Thu Oct 22 21:13:49 PDT 2009
Error messages are both sent to an optional user-provided logfile,
and, if CONFIG_CHECKPOINT_DEBUG=y, sent to syslog.
Signed-off-by: Serge E. Hallyn <serue at us.ibm.com>
---
checkpoint/objhash.c | 2 +
checkpoint/sys.c | 61 ++++++++++++++++++++++++++++++++++---
include/linux/checkpoint.h | 2 +-
include/linux/checkpoint_types.h | 1 +
include/linux/syscalls.h | 5 ++-
5 files changed, 63 insertions(+), 8 deletions(-)
diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index 730dd82..c441ce6 100644
--- a/checkpoint/objhash.c
+++ b/checkpoint/objhash.c
@@ -858,6 +858,8 @@ int ckpt_obj_contained(struct ckpt_ctx *ctx)
/* account for ctx->file reference (if in the table already) */
ckpt_obj_users_inc(ctx, ctx->file, 1);
+ if (ctx->logfile)
+ ckpt_obj_users_inc(ctx, ctx->logfile, 1);
/* account for ctx->root_nsproxy reference (if in the table already) */
ckpt_obj_users_inc(ctx, ctx->root_nsproxy, 1);
diff --git a/checkpoint/sys.c b/checkpoint/sys.c
index 260a1ee..1840f90 100644
--- a/checkpoint/sys.c
+++ b/checkpoint/sys.c
@@ -204,6 +204,8 @@ static void ckpt_ctx_free(struct ckpt_ctx *ctx)
if (ctx->file)
fput(ctx->file);
+ if (ctx->logfile)
+ fput(ctx->logfile);
ckpt_obj_hash_free(ctx);
path_put(&ctx->fs_mnt);
@@ -225,7 +227,7 @@ static void ckpt_ctx_free(struct ckpt_ctx *ctx)
}
static struct ckpt_ctx *ckpt_ctx_alloc(int fd, unsigned long uflags,
- unsigned long kflags)
+ unsigned long kflags, int logfd)
{
struct ckpt_ctx *ctx;
int err;
@@ -238,6 +240,9 @@ static struct ckpt_ctx *ckpt_ctx_alloc(int fd, unsigned long uflags,
ctx->kflags = kflags;
ctx->ktime_begin = ktime_get();
+ /* If logfd's a bad fd that's fine, no log output required... */
+ ctx->logfile = fget(logfd);
+
atomic_set(&ctx->refcount, 0);
INIT_LIST_HEAD(&ctx->pgarr_list);
INIT_LIST_HEAD(&ctx->pgarr_pool);
@@ -339,6 +344,51 @@ int walk_task_subtree(struct task_struct *root,
return (ret < 0 ? ret : total);
}
+/*
+ * currentpid:targetpid fmt%args
+ */
+void ckpt_log_error(struct ckpt_ctx *ctx, char *fmt, ...)
+{
+ mm_segment_t fs;
+ struct file *file;
+ int count;
+ char buf[200], *bufp = buf;
+ int mypid = current->pid;
+ int tpid = current->nsproxy ? task_pid_vnr(current) : -1;
+ va_list args;
+
+ if (!ctx || !ctx->logfile)
+ return;
+ file = ctx->logfile;
+
+ count = snprintf(buf, 200, "%d:%d ", mypid, tpid);
+ if (count > 200)
+ return; /* not possible */
+ fs = get_fs();
+ set_fs(KERNEL_DS);
+ _ckpt_kwrite(file, bufp, count);
+ set_fs(fs);
+
+ va_start(args, fmt);
+ count = vsnprintf(bufp, 200, fmt, args);
+ va_end(args);
+ if (count > 200) {
+ bufp = kmalloc(count, GFP_KERNEL);
+ if (!bufp)
+ return;
+ va_start(args, fmt);
+ vsnprintf(bufp, count, fmt, args);
+ va_end(args);
+ }
+
+ fs = get_fs();
+ set_fs(KERNEL_DS);
+ _ckpt_kwrite(file, bufp, count);
+ set_fs(fs);
+
+ if (bufp != buf)
+ kfree(bufp);
+}
/**
* sys_checkpoint - checkpoint a container
@@ -349,7 +399,8 @@ int walk_task_subtree(struct task_struct *root,
* Returns positive identifier on success, 0 when returning from restart
* or negative value on error
*/
-SYSCALL_DEFINE3(checkpoint, pid_t, pid, int, fd, unsigned long, flags)
+SYSCALL_DEFINE4(checkpoint, pid_t, pid, int, fd, unsigned long, flags,
+ int, logfd)
{
struct ckpt_ctx *ctx;
long ret;
@@ -362,7 +413,7 @@ SYSCALL_DEFINE3(checkpoint, pid_t, pid, int, fd, unsigned long, flags)
if (pid == 0)
pid = task_pid_vnr(current);
- ctx = ckpt_ctx_alloc(fd, flags, CKPT_CTX_CHECKPOINT);
+ ctx = ckpt_ctx_alloc(fd, flags, CKPT_CTX_CHECKPOINT, logfd);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
@@ -384,7 +435,7 @@ SYSCALL_DEFINE3(checkpoint, pid_t, pid, int, fd, unsigned long, flags)
* Returns negative value on error, or otherwise returns in the realm
* of the original checkpoint
*/
-SYSCALL_DEFINE3(restart, pid_t, pid, int, fd, unsigned long, flags)
+SYSCALL_DEFINE4(restart, pid_t, pid, int, fd, unsigned long, flags, int, logfd)
{
struct ckpt_ctx *ctx = NULL;
long ret;
@@ -397,7 +448,7 @@ SYSCALL_DEFINE3(restart, pid_t, pid, int, fd, unsigned long, flags)
return -EPERM;
if (pid)
- ctx = ckpt_ctx_alloc(fd, flags, CKPT_CTX_RESTART);
+ ctx = ckpt_ctx_alloc(fd, flags, CKPT_CTX_RESTART, logfd);
if (IS_ERR(ctx))
return PTR_ERR(ctx);
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 351f9ac..daba68c 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -371,7 +371,7 @@ static inline void restore_debug_free(struct ckpt_ctx *ctx) {}
#endif /* CONFIG_CHECKPOINT_DEBUG */
-#define ckpt_log_error(ctx, fmt, args...) do { } while (0)
+extern void ckpt_log_error(struct ckpt_ctx *ctx, char *fmt, ...);
#define ckpt_error(ctx, fmt, args...) \
do { \
diff --git a/include/linux/checkpoint_types.h b/include/linux/checkpoint_types.h
index fa57cdc..264afbd 100644
--- a/include/linux/checkpoint_types.h
+++ b/include/linux/checkpoint_types.h
@@ -48,6 +48,7 @@ struct ckpt_ctx {
unsigned long oflags; /* restart: uflags from checkpoint */
struct file *file; /* input/output file */
+ struct file *logfile; /* debug log file */
int total; /* total read/written */
atomic_t refcount;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 33bce6e..4fce331 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -754,8 +754,9 @@ asmlinkage long sys_pselect6(int, fd_set __user *, fd_set __user *,
asmlinkage long sys_ppoll(struct pollfd __user *, unsigned int,
struct timespec __user *, const sigset_t __user *,
size_t);
-asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags);
-asmlinkage long sys_restart(pid_t pid, int fd, unsigned long flags);
+asmlinkage long sys_checkpoint(pid_t pid, int fd, unsigned long flags,
+ int logfd);
+asmlinkage long sys_restart(pid_t pid, int fd, unsigned long flags, int logfd);
int kernel_execve(const char *filename, char *const argv[], char *const envp[]);
--
1.6.1
_______________________________________________
Containers mailing list
Containers at lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/containers
More information about the Devel
mailing list