[Devel] [PATCH 04/22] Change to the new enhanced error string format
serue at us.ibm.com
serue at us.ibm.com
Fri Oct 30 16:00:26 PDT 2009
From: Serge E. Hallyn <serue at us.ibm.com>
Signed-off-by: Serge E. Hallyn <serue at us.ibm.com>
---
checkpoint/checkpoint.c | 15 ++----
checkpoint/sys.c | 122 ++++++++++++++++++++++----------------------
include/linux/checkpoint.h | 12 ++--
3 files changed, 72 insertions(+), 77 deletions(-)
diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index 49f6e9d..c835d82 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -96,8 +96,7 @@ int ckpt_write_string(struct ckpt_ctx *ctx, char *str, int len)
return ckpt_write_obj_type(ctx, str, len, CKPT_HDR_STRING);
}
-static void ckpt_fill_err_string(struct ckpt_ctx *ctx, char *fmt0,
- char *fmt, va_list ap)
+static void ckpt_fill_err_string(struct ckpt_ctx *ctx, char *fmt, va_list ap)
{
va_list aq;
int len;
@@ -105,7 +104,7 @@ static void ckpt_fill_err_string(struct ckpt_ctx *ctx, char *fmt0,
spin_lock_irqsave(&ctx->err_string_lock, flags);
spin_lock(&ctx->fmt_buf_lock);
- ckpt_generate_fmt(ctx, fmt0, fmt);
+ ckpt_generate_fmt(ctx, fmt);
va_copy(aq, ap);
if (ctx->err_string_len == CKPT_MSG_BUFSZ)
@@ -147,14 +146,12 @@ out_unlock:
/**
* __ckpt_write_err - save an error string on the ctx->err_string
* @ctx: checkpoint context
- * @fmt0: error pre-format
* @fmt: message format
* @...: arguments
*
- * See _ckpt_generate_fmt for information on @fmt0.
* Use this during checkpoint to report while holding a spinlock
*/
-void __ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...)
+void __ckpt_write_err(struct ckpt_ctx *ctx, char *fmt, ...)
{
va_list ap;
@@ -166,21 +163,19 @@ void __ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...)
/**
* ckpt_write_err - write an object describing an error
* @ctx: checkpoint context
- * @pre: string pre-format
* @fmt: error string format
* @...: error string arguments
*
- * See _ckpt_generate_fmt for information on @fmt0.
* If @fmt is null, the string in the ctx->err_string will be used (and freed)
*/
-int ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...)
+int ckpt_write_err(struct ckpt_ctx *ctx, char *fmt, ...)
{
va_list ap;
int i, len, ret = 0;
if (fmt) {
va_start(ap, fmt);
- ckpt_fill_err_string(ctx, fmt, ap);
+ ckpt_fill_err_string(ctx, fmt, ap);
va_end(ap);
}
diff --git a/checkpoint/sys.c b/checkpoint/sys.c
index 8810576..e2c01df 100644
--- a/checkpoint/sys.c
+++ b/checkpoint/sys.c
@@ -345,83 +345,83 @@ int walk_task_subtree(struct task_struct *root,
}
/*
- * ckpt_generate_fmt - generate standard checkpoint error message
+ * ckpt_generate_fmt - handle the special flags in the enhanced format
+ * strings used by checkpoint/restart error messages.
* @ctx: checkpoint context
- * @fmt0: c/r-format string
* @fmt: message format
*
- * This generates a unified format of checkpoint error messages, to
- * ease (after the failure) inspection by userspace tools. It converts
- * the (printf) message @fmt into a new format: "[PREFMT]: fmt".
+ * The special flags are surrounded by %() to help them visually stand
+ * out. For instance, %(O) means an objref. The following special
+ * flags are recognized:
+ * E: error
+ * O: objref
+ * P: pointer
+ * T: task
+ * S: string
+ * V: variable
*
- * PREFMT is constructed from @fmt0 by subtituting format snippets
- * according to the contents of @fmt0. The format characters in
- * @fmt0 can be E (error), O (objref), P (pointer), S (string) and
- * V (variable/symbol). For example, E will generate a "err %d" in
- * PREFMT (see prefmt_array below).
- *
- * If @fmt0 begins with T, PREFMT will begin with "pid %d tsk %s"
- * with the pid and the tsk->comm of the currently checkpointed task.
- * The latter is taken from ctx->tsk, and is it the responsbilility of
- * the caller to have a valid pointer there (in particular, functions
- * that iterate on the processes: collect_objects, checkpoint_task,
- * and tree_count_tasks).
+ * %(E) will be expanded to "[err %d]". Likewise O, P, S, and V, will
+ * also expand to format flags requiring an argument to the subsequent
+ * sprintf or printk. T will be expanded to a string with no flags,
+ * requiring no further arguments.
*
* The caller of ckpt_write_err() and _ckpt_write_err() must provide
- * the additional variabes, in order, to match the @fmt0 (except for
+ * the additional variabes, in order, to match the @fmt (except for
* the T key), e.g.:
*
- * ckpt_writ_err(ctx, "TEO", "FILE flags %d", err, objref, flags);
- *
- * Here, T is simply passed, E expects an integer (err), O expects an
- * integer (objref), and the last argument matches the format string.
+ * ckpt_write_err(ctx, "%(T)FILE flags %d %O %E\n", flags, objref, err);
*
* Must be called with ctx->fmt_buf_lock held. The expanded format
* will be placed in ctx->fmt_buf.
*/
-char *ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt0, char *fmt)
+void ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt)
{
- char *format = ctx->fmt_buf;
- int i, j, len = 0;
-
- static struct {
- char key;
- char *fmt;
- } prefmt_array[] = {
- { 'E', "err %d" },
- { 'O', "obj %d" },
- { 'P', "ptr %p" },
- { 'V', "sym %pS" },
- { 'S', "str %s" },
- { 0, "??? %pS" },
- };
-
- format[len++] = '[';
-
- if (fmt0[0] == 'T') {
- if (ctx->tsk)
- len = sprintf(format, "pid %d tsk %s ",
+ char *s = ctx->fmt_buf;
+ int len = 0;
+ int first = 1;
+
+ for (; *fmt && len < CKPT_MSG_BUFSZ; fmt++) {
+ if (*fmt != '%' || fmt[1] != '(' || fmt[2] == '\0' ||
+ fmt[3] != ')') {
+ s[len++] = *fmt;
+ continue;
+ }
+ if (!first)
+ s[len++] = ' ';
+ else
+ first = 0;
+ switch (fmt[2]) {
+ case 'E':
+ len += sprintf(s+len, "[%s]", "err %d");
+ break;
+ case 'O':
+ len += sprintf(s+len, "[%s]", "obj %d");
+ break;
+ case 'P':
+ len += sprintf(s+len, "[%s]", "ptr %p");
+ break;
+ case 'V':
+ len += sprintf(s+len, "[%s]", "sym %pS");
+ break;
+ case 'S':
+ len += sprintf(s+len, "[%s]", "str %s");
+ break;
+ case 'T':
+ if (ctx->tsk)
+ len += sprintf(s+len, "[pid %d tsk %s]",
task_pid_vnr(ctx->tsk), ctx->tsk->comm);
- else if (warn_notask++ < 5)
- printk(KERN_ERR "c/r: no target task set\n");
- fmt0++;
- }
+ else
+ len += sprintf(s+len, "[pid -1 tsk NULL]");
+ break;
+ default:
+ printk(KERN_ERR "c/r: bad format specifier %c\n",
+ fmt[2]);
+ BUG();
+ }
- for (i = 0; i < strlen(fmt0); i++) {
- for (j = 0; prefmt_array[j].key; j++)
- if (prefmt_array[j].key == fmt0[i])
- break;
- if (!prefmt_array[j].key && warn_prefmt++ < 5)
- printk(KERN_ERR "c/r: unknown prefmt %c\n", fmt0[i]);
- len += sprintf(&format[len], "%s ", prefmt_array[j].fmt);
+ fmt += 3;
}
-
- if (len > 1)
- sprintf(&format[len-1], "]: %s", fmt); /* erase last space */
- else
- sprintf(format, "%s", fmt);
-
- return format;
+ s[len] = '\0';
}
/**
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index 4cfd44b..6464851 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -70,12 +70,12 @@ extern int ckpt_write_buffer(struct ckpt_ctx *ctx, void *ptr, int len);
extern int ckpt_write_string(struct ckpt_ctx *ctx, char *str, int len);
/*
- * Generate a checkpoint error message with unified format, of the
- * form: "[PREFMT]: @fmt", where PREFMT is constructed from @fmt0. See
- * checkpoint/checkpoint.c:__ckpt_generate_fmt() for details.
+ * Generate a checkpoint error message with unified format. Format
+ * can include tokens like %(E) for checkpoint-specific arguments,
+ * which must come before non-checkpoint-specific ones.
*/
-extern void __ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...);
-extern int ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...);
+extern void __ckpt_write_err(struct ckpt_ctx *ctx, char *fmt, ...);
+extern int ckpt_write_err(struct ckpt_ctx *ctx, char *fmt, ...);
extern int _ckpt_read_obj_type(struct ckpt_ctx *ctx,
void *ptr, int len, int type);
@@ -370,7 +370,7 @@ static inline void restore_debug_free(struct ckpt_ctx *ctx) {}
#endif /* CONFIG_CHECKPOINT_DEBUG */
-extern void ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt0, char *fmt);
+extern void ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt);
static inline void ckpt_do_write_msg(struct ckpt_ctx *ctx) { }
#endif /* CONFIG_CHECKPOINT */
--
1.6.1
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