fix(klibc\kstdio): vsnprinf size_t can not exceed INT32_MAX, don't u…

[liuyangzys]

…se (rt_size_t -1)

拉取/合并请求描述：(PR description)

[

开启RT_KLIBC_USING_LIBC_VSNPRINTF后，rt_vsprintf 执行异常。排查原因为 vsnprinf 的 size 参数不能超过 INT32 最大值。

编译器

arm-none-eabi-gcc v10.3.1

mcu

stm32h7xx

]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

• 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
• 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
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• 代码是高质量的 Code in this PR is of high quality
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[Copilot]

Pull Request Overview

This PR addresses an issue with rt_vsprintf by ensuring that the size parameter passed to rt_vsnprintf does not exceed the maximum allowed value. The change replaces the previously used (rt_size_t)-1 with INT32_MAX to enforce the correct upper limit.

• Changes rt_vsprintf to call rt_vsnprintf with INT32_MAX
• Aligns the size parameter with the constraints of vsnprintf on target platforms

Comments suppressed due to low confidence (1)

src/klibc/kstdio.c:54

• Replacing (rt_size_t)-1 with INT32_MAX enforces the correct maximum size for rt_vsnprintf. Please ensure that INT32_MAX is defined and available on all target platforms.

return rt_vsnprintf(buf, INT32_MAX, format, arg_ptr);

[liuyangzys]

这个问题完全可以复现的，编译器直接就会警告。所有相关的rt_vsprintf数都会执行失败返回-1。感觉应该尽快修复

[supperthomas]

rt_vsprintf

可否具体讲讲复现方法吗？这边ci检测看起来没有报warning。
https://github.com/RT-Thread/rt-thread/actions/runs/14599436945/job/40953639237

[supperthomas]

rt_vsprintf

可否具体讲讲复现方法吗？这边ci检测看起来没有报warning。 https://github.com/RT-Thread/rt-thread/actions/runs/14599436945/job/40953639237

或者也可以把报错截图发出来

[liuyangzys]

rt_vsprintf

可否具体讲讲复现方法吗？这边ci检测看起来没有报warning。 https://github.com/RT-Thread/rt-thread/actions/runs/14599436945/job/40953639237

或者也可以把报错截图发出来

需要使能使用 libc的 vsnprintf

[lianux-mm]

lgtm