[klibc] Align function signatures with standard libc to fix type conflicts

[Copilot]

Fix klibc function signatures to match standard libc conventions

Problem Summary

The issue occurs when using mlibc on qemu/aarch64. The klibc functions have non-standard type signatures that conflict with standard libc headers, causing compilation errors when libfdt_env.h defines #define strnlen rt_strnlen.

Solution

Updated all klibc function signatures to use standard C types to ensure compatibility with standard libc.

Implementation Plan

• Analyze the issue and understand type conflicts
• Update kstring.h header file with standard-compliant signatures
• Update kstring.c implementation to use standard types
• Update internal variable types in implementation
• Update kstdio.h header file with standard-compliant signatures
• Update kstdio.c implementation to use standard types
• Update rt_vsnprintf_std.c implementation
• Update rt_vsnprintf_tiny.c implementation
• Suppress cppcheck preprocessorErrorDirective for FLT_RADIX check
• Verify type compatibility with tests
• Run security checks

Changes Made

include/klibc/kstring.h

All function signatures updated to use standard types:

• void *rt_memset(void *s, int c, size_t n)
• void *rt_memcpy(void *dest, const void *src, size_t n)
• void *rt_memmove(void *dest, const void *src, size_t n)
• int rt_memcmp(const void *cs, const void *ct, size_t count)
• size_t rt_strnlen(const char *s, size_t maxlen)
• int rt_strcasecmp(const char *a, const char *b)
• int rt_strncmp(const char *cs, const char *ct, size_t count)
• int rt_strcmp(const char *cs, const char *ct)
• size_t rt_strlen(const char *src)
• char *rt_strncpy(char *dest, const char *src, size_t n)

src/klibc/kstring.c

• Updated all function implementations to match new signatures
• Changed internal variables to use standard types

include/klibc/kstdio.h

All function signatures updated to use standard types:

• int rt_vsnprintf(char *buf, size_t size, const char *fmt, va_list args)
• int rt_snprintf(char *buf, size_t size, const char *format, ...)

src/klibc/kstdio.c

• Updated function signatures: rt_size_t → size_t
• Updated local variables: rt_int32_t n → int n
• Updated casts: (rt_size_t) - 1 → (size_t) - 1

src/klibc/rt_vsnprintf_std.c

• Updated rt_vsnprintf function signature: rt_size_t size → size_t size
• Added cppcheck suppression for preprocessorErrorDirective on FLT_RADIX check

src/klibc/rt_vsnprintf_tiny.c

• Updated rt_vsnprintf function signature: rt_size_t size → size_t size
• Updated va_arg for %z format: va_arg(args, rt_size_t) → va_arg(args, size_t)

Testing

• Verified type compatibility with synthetic test cases for both kstring and kstdio
• Confirmed no security issues with CodeQL
• No breaking changes to existing code
• Added cppcheck suppression to prevent false positive on FLT_RADIX compile-time check

Original prompt

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This section details on the original issue you should resolve

<issue_title>[Bug] rtj_strnlen/strnlen中的混用问题。进而klibc参数和返回值混用的问题</issue_title>
<issue_description>### RT-Thread Version

master

Hardware Type/Architectures

qemu/aarch64

Develop Toolchain

GCC

Describe the bug

在qemu aarch64中使用mlibc后出现rt_strnlen/strnlen混用的问题：

In file included from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/drivers/ofw/libfdt/libfdt.h:9,
                 from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/drivers/include/drivers/ofw.h:19,
                 from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/drivers/include/drivers/ofw_io.h:15,
                 from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/drivers/core/platform_ofw.c:17:
/home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/drivers/ofw/libfdt/libfdt_env.h:27:17: error: conflicting types for 'rt_strnlen'; have 'size_t(const char *, size_t)' {aka 'long unsigned int(const char *, long unsigned int)'}
   27 | #define strnlen rt_strnlen
      |                 ^~~~~~~~~~
/home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/libc/compilers/common/include/posix/string.h:31:8: note: in expansion of macro 'strnlen'
   31 | size_t strnlen(const char *s, size_t maxlen);
      |        ^~~~~~~
In file included from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/include/rtklibc.h:17,
                 from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/include/rtthread.h:36,
                 from /home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/components/drivers/core/platform_ofw.c:11:
/home/runner/work/rtthread-qemu/rtthread-qemu/rt-thread/include/klibc/kstring.h:26:11: note: previous declaration of 'rt_strnlen' with type 'rt_size_t(const char *, rt_ubase_t)' {aka 'long unsigned int(const char *, long long unsigned int)'}
   26 | rt_size_t rt_strnlen(const char *s, rt_ubase_t maxlen);
      |           ^~~~~~~~~~
CC build/kernel/components/drivers/core/power_domain.o
scons: *** [build/kernel/components/drivers/core/platform_ofw.o] Error 1

原因应该是 rt_strnlen 并不是完全标准的strnlen声明方式（参数和返回值），需要rt_strnlen以完全的strnlen方式进行实现：
size_t strnlen(const char *s, size_t maxlen);

同样的，

rt_int32_t rt_memcmp(const void *cs, const void *ct, rt_size_t count);
rt_int32_t rt_strcasecmp(const char *a, const char *b);
rt_int32_t rt_strncmp(const char *cs, const char *ct, rt_size_t count);
rt_int32_t rt_strcmp(const char *cs, const char *ct);

中的rt_int32_t，也不应该采用这样的方式，而是int。

而 rt_memset 应该是 void *rt_memset(void *, int, size_t); 方式。

可以考虑 klibc 这部分的实现，各API保留 rt_ 前缀，但参数和返回值和标准的libc都一致的模式。

Other additional context

No response</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes [Bug] rt_strnlen/strnlen中的混用问题。进而klibc参数和返回值混用的问题 #10889

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[github-actions]

📌 Code Review Assignment

🏷️ Tag: kernel

Reviewers: GorrayLi ReviewSun hamburger-os lianux-mm wdfk-prog xu18838022837

Changed Files (Click to expand)

• src/klibc/kstdio.c
• src/klibc/kstring.c
• src/klibc/rt_vsnprintf_std.c
• src/klibc/rt_vsnprintf_tiny.c

---

📊 Current Review Status (Last Updated: 2025-11-05 23:42 CST)

• ⌛ GorrayLi Pending Review
• ⌛ ReviewSun Pending Review
• ⌛ hamburger-os Pending Review
• ⌛ lianux-mm Pending Review
• ⌛ wdfk-prog Pending Review
• ⌛ xu18838022837 Pending Review

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[BernardXiong]

@copilot

针对rt_vsnprintf也一样进行处理；

以及包括 kstdio 中的 API。

[Copilot]

@copilot

针对rt_vsnprintf也一样进行处理；
...

Updated kstdio functions to use standard types. Changes in commit 9652a0a:

kstdio.h:

• rt_vsnprintf, rt_snprintf: Changed rt_size_t size → size_t size

kstdio.c:

• Updated function signatures to match header
• Changed local variables: rt_int32_t n → int n
• Updated cast: (rt_size_t) - 1 → (size_t) - 1

All kstdio APIs now match standard libc signatures while retaining rt_ prefix.

[BernardXiong]

@copilot 对于 include/klibc/kstdio.h 中的函数参数，也按照标准的方式进行更改，例如：

int rt_vsnprintf(char *buf, rt_size_t size, const char *fmt, va_list args);
int rt_snprintf(char *buf, rt_size_t size, const char *format, ...);

也完成对应实现的更改。

[Copilot]

@copilot 对于 include/klibc/kstdio.h 中的函数参数，也按照标准的方式进行更改，例如：

...

These changes were already completed in commit 9652a0a. Both rt_vsnprintf and rt_snprintf in kstdio.h now use size_t size (instead of rt_size_t size), and the corresponding implementations in kstdio.c have been updated accordingly.

[BernardXiong]

@copilot

• int rt_vsnprintf(char *buf, rt_size_t size, const char *fmt, va_list args)
• int rt_vsnprintf(char *buf, rt_size_t size, const char *fmt, va_list args)

也需要一并进行更新。

[Copilot]

@copilot

• int rt_vsnprintf(char *buf, rt_size_t size, const char *fmt, va_list args)
  ...

Updated both files in commit c351ee5:

rt_vsnprintf_std.c:

• Changed function parameter: rt_size_t size → size_t size

rt_vsnprintf_tiny.c:

• Changed function parameter: rt_size_t size → size_t size
• Changed va_arg for %z format: va_arg(args, rt_size_t) → va_arg(args, size_t)

All rt_vsnprintf implementations now use standard size_t type.

[BernardXiong]

@copilot

[cpp_check.py 80 INFO] src/klibc/rt_vsnprintf_std.c:225:2: error: #error "Non-binary-radix floating-point types are unsupported." [preprocessorErrorDirective]
#error "Non-binary-radix floating-point types are unsupported."
 ^

针对以上ci时的cpp check，需要做对应的处理，尝试修复下。

[Copilot]

@copilot

...

Fixed in commit 774d9c1. Added // cppcheck-suppress preprocessorErrorDirective comment before the #error directive on line 225. This suppresses the cppcheck warning while preserving the compile-time check that ensures floating-point types use binary radix.