[Devel] [RFC PATCH 11/17] define function to print error messages to user log
Serge Hallyn
serge at us.ibm.com
Tue Oct 27 15:48:04 PDT 2009
From: Serge E. Hallyn <serue at us.ibm.com>
Error messages are both sent to an optional user-provided logfile,
and, if CONFIG_CHECKPOINT_DEBUG=y, sent to syslog.
Changelog:
Oct 27: add %(C) for ctx->total.
Oct 26: Per Oren suggestion, return -EBADF for bad
logfile in ckpt_ctx_alloc().
Signed-off-by: Serge E. Hallyn <serue at us.ibm.com>
---
checkpoint/objhash.c | 2 +
checkpoint/sys.c | 67 +++++++++++++++++++++++++++++++++++---
include/linux/checkpoint.h | 5 +++
include/linux/checkpoint_types.h | 1 +
include/linux/syscalls.h | 5 ++-
5 files changed, 73 insertions(+), 7 deletions(-)
diff --git a/checkpoint/objhash.c b/checkpoint/objhash.c
index a152e69..25b9c10 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 38e65e4..ab0f294 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;
@@ -254,6 +256,12 @@ static struct ckpt_ctx *ckpt_ctx_alloc(int fd, unsigned long uflags,
if (!ctx->file)
goto err;
+ if (logfd != -1) {
+ ctx->logfile = fget(logfd);
+ if (!ctx->logfile)
+ goto err;
+ }
+
err = -ENOMEM;
if (ckpt_obj_hash_alloc(ctx) < 0)
goto err;
@@ -401,6 +409,9 @@ char *ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt)
case 'E':
len += sprintf(format+len, "[%s]", "err %d");
break;
+ case 'C': /* count of bytes read/written to checkpoint image */
+ len += sprintf(format+len, "[%s]", "pos %d");
+ break;
case 'O':
len += sprintf(format+len, "[%s]", "obj %d");
break;
@@ -435,6 +446,51 @@ char *ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt)
return format;
}
+void ckpt_log_error(struct ckpt_ctx *ctx, char *fmt, ...)
+{
+ mm_segment_t fs;
+ struct file *file;
+ int count;
+ va_list ap, aq, az;
+ char *format;
+ char buf[200], *bufp = buf;
+
+ if (!ctx || !ctx->logfile)
+ return;
+ file = ctx->logfile;
+
+ va_start(ap, fmt);
+ format = ckpt_generate_fmt(ctx, fmt);
+ va_copy(aq, ap);
+ va_copy(az, ap);
+ /* I'm not clear here - can I re-use aq, or do i need
+ * a third copy? */
+ count = vsnprintf(bufp, 200, format ? : fmt, aq);
+ if (count > 200) {
+ bufp = kmalloc(count, GFP_KERNEL);
+ if (!bufp)
+ goto out_free;
+ vsnprintf(bufp, count, format ? : fmt, az);
+ }
+
+ fs = get_fs();
+ set_fs(KERNEL_DS);
+ _ckpt_kwrite(file, bufp, count);
+ set_fs(fs);
+
+#ifdef CONFIG_CHECKPOINT_DEBUG
+ vprintk(format, aq);
+#endif
+
+out_free:
+ kfree(format);
+ va_end(aq);
+ va_end(ap);
+ va_end(az);
+ if (bufp != buf)
+ kfree(bufp);
+}
+
/**
* sys_checkpoint - checkpoint a container
* @pid: pid of the container init(1) process
@@ -444,7 +500,8 @@ char *ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt)
* 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;
@@ -457,7 +514,7 @@ 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);
@@ -479,7 +536,7 @@ 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;
@@ -492,7 +549,7 @@ 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 8a1eaa7..91e0066 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -372,6 +372,11 @@ static inline void restore_debug_free(struct ckpt_ctx *ctx) {}
#endif /* CONFIG_CHECKPOINT_DEBUG */
extern char *ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt);
+extern void ckpt_log_error(struct ckpt_ctx *ctx, char *fmt, ...);
+
+#define ckpt_error(ctx, fmt, args...) \
+ ckpt_log_error(ctx, "%s:%d %(C)" fmt, __func__, __LINE__, \
+ ctx ? ctx->total : -1, ## args);
#endif /* CONFIG_CHECKPOINT */
#endif /* __KERNEL__ */
diff --git a/include/linux/checkpoint_types.h b/include/linux/checkpoint_types.h
index 5cc11d9..c6dcd4f 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 */
loff_t 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
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