serue@xxxxxxxxxx [serue@xxxxxxxxxx] wrote:
| 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.
It maybe easier to review this patch if this is broken up into smaller
patches:
- move the code to new place
- leave the fmt0 parameter to ckpt_generate_fmt() but ensure it
is unused.
- finally remove the unused parameters from ckpt_generate_fmt()
and the callers.
|
| 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.
Its a little confusing on what PREFMT is and how it differs from @fmt0.
The [] with all upper case makes it look like the P, R, E etc are the
only valid characters for fmt0. Can we s/[PREFMT]/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);
s/writ/write/
| + *
| + * 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?
I think it would make sense to.
| + */
| +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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