From: Serge E. Hallyn <serue@xxxxxxxxxx>
Matt Helsley originally suggested this to avoid having two
format strings. This is not bisect-safe and therefore not
even compile-tested. Every call to ckpt_write_err must be
updated to use a single format.
Changelog:
Oct 29: merge with the next patch, moving ckpt_generate_fmt()
into checkpoing/sys.c and making it non-static so that
we can use it in ckpt_error().
Oct 28: also fix comment above ckpt_generate_fmt()
Oct 27: ensure %(T) has a closing paren
Signed-off-by: Serge E. Hallyn <serue@xxxxxxxxxx>
---
checkpoint/checkpoint.c | 105 +++-----------------------------------------
checkpoint/sys.c | 95 +++++++++++++++++++++++++++++++++++++++
include/linux/checkpoint.h | 13 +++--
3 files changed, 110 insertions(+), 103 deletions(-)
diff --git a/checkpoint/checkpoint.c b/checkpoint/checkpoint.c
index 6eb8f3b..c6be4f9 100644
--- a/checkpoint/checkpoint.c
+++ b/checkpoint/checkpoint.c
@@ -96,104 +96,15 @@ int ckpt_write_string(struct ckpt_ctx *ctx, char *str, int len)
return ckpt_write_obj_type(ctx, str, len, CKPT_HDR_STRING);
}
-/*
- * __ckpt_generate_fmt - generate standard checkpoint error message
- * @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".
- *
- * 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).
- *
- * The caller of ckpt_write_err() and _ckpt_write_err() must provide
- * the additional variabes, in order, to match the @fmt0 (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.
- */
-static char *__ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt0, char *fmt)
-{
- static int warn_notask = 0;
- static int warn_prefmt = 0;
- char *format;
- 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" },
- };
-
- /*
- * 17 for "pid %d" (plus space)
- * 21 for "tsk %s" (tsk->comm)
- * up to 8 per varfmt entry
- */
- format = kzalloc(37 + 8 * strlen(fmt0) + strlen(fmt), GFP_KERNEL);
- if (!format)
- return NULL;
-
- format[len++] = '[';
-
- if (fmt0[0] == 'T') {
- if (ctx->tsk)
- len = sprintf(format, "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++;
- }
-
- 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);
- }
-
- if (len > 1)
- sprintf(&format[len-1], "]: %s", fmt); /* erase last space */
- else
- sprintf(format, "%s", fmt);
-
- return format;
-}
-
-/* see _ckpt_generate_fmt for information on @fmt0 */
-static void __ckpt_generate_err(struct ckpt_ctx *ctx, char *fmt0,
- char *fmt, va_list ap)
+/* see ckpt_generate_fmt for information on @fmt extensions */
+static void __ckpt_generate_err(struct ckpt_ctx *ctx, char *fmt, va_list ap)
{
va_list aq;
char *format;
char *str;
int len;
- format = __ckpt_generate_fmt(ctx, fmt0, fmt);
+ format = ckpt_generate_fmt(ctx, fmt);
va_copy(aq, ap);
/*
@@ -223,15 +134,14 @@ static void __ckpt_generate_err(struct ckpt_ctx *ctx, char *fmt0,
* @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;
va_start(ap, fmt);
- __ckpt_generate_err(ctx, fmt0, fmt, ap);
+ __ckpt_generate_err(ctx, fmt, ap);
va_end(ap);
}
@@ -242,10 +152,9 @@ void __ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...)
* @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;
char *str;
@@ -253,7 +162,7 @@ int ckpt_write_err(struct ckpt_ctx *ctx, char *fmt0, char *fmt, ...)
if (fmt) {
va_start(ap, fmt);
- __ckpt_generate_err(ctx, fmt0, fmt, ap);
+ __ckpt_generate_err(ctx, fmt, ap);
va_end(ap);
}
diff --git a/checkpoint/sys.c b/checkpoint/sys.c
index 260a1ee..9b2de18 100644
--- a/checkpoint/sys.c
+++ b/checkpoint/sys.c
@@ -339,6 +339,101 @@ int walk_task_subtree(struct task_struct *root,
return (ret < 0 ? ret : total);
}
+/*
+ * ckpt_generate_fmt - generate standard checkpoint error message
+ * @ctx: checkpoint context
+ * @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".
+ *
+ * PREFMT is constructed from @fmt by subtituting format snippets
+ * according to the contents of @fmt. The format characters in
+ * @fmt can be %(E) (error), %(O) (objref), %(P) (pointer), %(S) (string),
+ * %(C) (bytes read/written out of checkpoint image so far), * and %(V)
+ * (variable/symbol). For example, %(E) will generate a "err %d"
+ * in PREFMT.
+ *
+ * If @fmt 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).
+ *
+ * The caller of ckpt_write_err() and _ckpt_write_err() must provide
+ * the additional variabes, in order, to match the @fmt0 (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.
+ *
+ * XXX Do we want 'T' and 'C' to simply always be prepended?
+ */
+char *ckpt_generate_fmt(struct ckpt_ctx *ctx, char *fmt)
+{
+ char *format;
+ int alloclen, len = 0;
+ int first = 1;
+
+ /*
+ * 17 for "pid %d" (plus space)
+ * 21 for "tsk %s" (tsk->comm)
+ * up to 8 per varfmt entry
+ */
+ alloclen = 37 + 8 * strlen(fmt);
+ format = kzalloc(alloclen, GFP_KERNEL);
+ if (!format)
+ return NULL;
+
+ for (; *fmt; fmt++) {
+ BUG_ON(len > alloclen);
+ if (*fmt != '%' || fmt[1] != '(' || fmt[3] != ')') {
+ format[len++] = *fmt;
+ continue;
+ }
+ if (!first)
+ format[len++] = ' ';
+ else
+ first = 0;
+ switch (fmt[2]) {
+ case 'E':
+ len += sprintf(format+len, "[%s]", "err %d");
+ break;
+ case 'O':
+ len += sprintf(format+len, "[%s]", "obj %d");
+ break;
+ case 'P':
+ len += sprintf(format+len, "[%s]", "ptr %p");
+ break;
+ case 'V':
+ len += sprintf(format+len, "[%s]", "sym %pS");
+ break;
+ case 'S':
+ len += sprintf(format+len, "[%s]", "str %s");
+ break;
+ case 'T':
+ if (ctx->tsk)
+ len += sprintf(format+len, "[pid %d tsk %s]",
+ task_pid_vnr(ctx->tsk), ctx->tsk->comm);
+ else
+ len += sprintf(format+len, "[pid -1 tsk NULL]");
+ break;
+ default:
+ printk(KERN_ERR "c/r: bad format specifier %c\n",
+ fmt[2]);
+ BUG();
+ }
+
+ fmt += 3;
+ }
+ format[len] = '\0';
+
+ return format;
+}
/**
* sys_checkpoint - checkpoint a container
diff --git a/include/linux/checkpoint.h b/include/linux/checkpoint.h
index dfcb59b..8a1eaa7 100644
--- a/include/linux/checkpoint.h
+++ b/include/linux/checkpoint.h
@@ -70,12 +70,13 @@ 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 %(T) for checkpoint-specific arguments,
+ * which must come before non-checkpoint-specific ones.
+ * See checkpoint/checkpoint.c:__ckpt_generate_fmt() for details.
*/
-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);
@@ -370,6 +371,8 @@ 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);
+
#endif /* CONFIG_CHECKPOINT */
#endif /* __KERNEL__ */
--
1.6.1
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