Messages in this thread Patch in this message | | | Date | Tue, 28 Sep 2004 19:19:34 -0700 | From | Roland Dreier <> | Subject | [PATCH][1/2] [take 2] kobject: add add_hotplug_env_var |
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Add a (non-inlined) add_hotplug_env_var() function to <linux/kobject.h> and lib/kobject.c. There's a lot of boilerplate code involved in setting environment variables in a hotplug method, so we should have a convenience function to consolidate it (and avoid subtle bugs).
Signed-off-by: Roland Dreier <roland@topspin.com>
Index: linux-bk/include/linux/kobject.h =================================================================== --- linux-bk.orig/include/linux/kobject.h 2004-09-28 09:51:09.000000000 -0700 +++ linux-bk/include/linux/kobject.h 2004-09-28 09:50:49.000000000 -0700 @@ -136,6 +136,32 @@ /** + * add_hotplug_env_var - helper for creating hotplug environment variables + * @envp: Pointer to table of environment variables, as passed into + * hotplug() method. + * @num_envp: Number of environment variable slots available, as + * passed into hotplug() method. + * @cur_index: Pointer to current index into @envp. It should be + * initialized to 0 before the first call to add_hotplug_env_var(), + * and will be incremented on success. + * @buffer: Pointer to buffer for environment variables, as passed + * into hotplug() method. + * @buffer_size: Length of @buffer, as passed into hotplug() method. + * @cur_len: Pointer to current length of space used in @buffer. + * Should be initialized to 0 before the first call to + * add_hotplug_env_var(), and will be incremented on success. + * @format: Format for creating environment variable (of the form + * "XXX=%x") for snprintf(). + * + * Returns 0 if environment variable was added successfully or -ENOMEM + * if no space was available. + */ +extern int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, + char *buffer, int buffer_size, int *cur_len, + const char *format, ...) + __attribute__((format (printf, 7, 8))); + +/** * Use this when initializing an embedded kset with no other * fields to initialize. */ Index: linux-bk/lib/kobject.c =================================================================== --- linux-bk.orig/lib/kobject.c 2004-09-28 09:30:17.000000000 -0700 +++ linux-bk/lib/kobject.c 2004-09-28 10:45:49.000000000 -0700 @@ -232,11 +232,51 @@ if (top_kobj->kset && top_kobj->kset->hotplug_ops) kset_hotplug(action, top_kobj->kset, kobj); } -#else + +int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, + char *buffer, int buffer_size, int *cur_len, + const char *format, ...) +{ + va_list args; + + /* + * We check against num_envp - 1 to make sure there is at + * least one slot left after we return, since the hotplug + * method needs to set the last slot to NULL. + */ + if (*cur_index >= num_envp - 1) + return -ENOMEM; + + envp[*cur_index] = buffer + *cur_len; + + va_start(args, format); + *cur_len += vsnprintf(envp[*cur_index], + max(buffer_size - *cur_len, 0), + format, args) + 1; + va_end(args); + + if (*cur_len > buffer_size) + return -ENOMEM; + + (*cur_index)++; + return 0; +} +EXPORT_SYMBOL(add_hotplug_env_var); + +#else /* CONFIG_HOTPLUG */ + void kobject_hotplug(const char *action, struct kobject *kobj) { return; } + +int add_hotplug_env_var(char **envp, int num_envp, int *cur_index, + char *buffer, int buffer_size, int *cur_len, + const char *format, ...) +{ + return 0; +} +EXPORT_SYMBOL(add_hotplug_env_var); #endif /* CONFIG_HOTPLUG */ /** - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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