From: Maximilian Luz <luzmaximilian@gmail.com>
To: Bjorn Andersson <andersson@kernel.org>
Cc: Maximilian Luz <luzmaximilian@gmail.com>,
Kees Cook <keescook@chromium.org>, Andy Gross <agross@kernel.org>,
Konrad Dybcio <konrad.dybcio@linaro.org>,
Ard Biesheuvel <ardb@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Sudeep Holla <sudeep.holla@arm.com>,
Johan Hovold <johan@kernel.org>,
Steev Klimaszewski <steev@kali.org>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v6 1/3] lib/ucs2_string: Add UCS-2 strscpy function
Date: Sun, 27 Aug 2023 23:14:04 +0200 [thread overview]
Message-ID: <20230827211408.689076-2-luzmaximilian@gmail.com> (raw)
In-Reply-To: <20230827211408.689076-1-luzmaximilian@gmail.com>
Add a ucs2_strscpy() function for UCS-2 strings. The behavior is
equivalent to the standard strscpy() function, just for 16-bit character
UCS-2 strings.
Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
---
Changes in v6:
- Add function documentation
- Clarify that we're copying/working in terms of characters, not bytes
- Change size warning to be INT_MAX bytes, not INT_MAX characters
Changes in v5:
- Add ucs2_strscpy() instead of ucs2_strlcpy()
Patch introduced in v4.
---
include/linux/ucs2_string.h | 1 +
lib/ucs2_string.c | 52 +++++++++++++++++++++++++++++++++++++
2 files changed, 53 insertions(+)
diff --git a/include/linux/ucs2_string.h b/include/linux/ucs2_string.h
index cf3ada3e820e..c499ae809c7d 100644
--- a/include/linux/ucs2_string.h
+++ b/include/linux/ucs2_string.h
@@ -10,6 +10,7 @@ typedef u16 ucs2_char_t;
unsigned long ucs2_strnlen(const ucs2_char_t *s, size_t maxlength);
unsigned long ucs2_strlen(const ucs2_char_t *s);
unsigned long ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength);
+ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count);
int ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len);
unsigned long ucs2_utf8size(const ucs2_char_t *src);
diff --git a/lib/ucs2_string.c b/lib/ucs2_string.c
index 0a559a42359b..9308bcfb2ad5 100644
--- a/lib/ucs2_string.c
+++ b/lib/ucs2_string.c
@@ -32,6 +32,58 @@ ucs2_strsize(const ucs2_char_t *data, unsigned long maxlength)
}
EXPORT_SYMBOL(ucs2_strsize);
+/**
+ * ucs2_strscpy() - Copy a UCS2 string into a sized buffer.
+ *
+ * @dst: Pointer to the destination buffer where to copy the string to.
+ * @src: Pointer to the source buffer where to copy the string from.
+ * @count: Size of the destination buffer, in UCS2 (16-bit) characters.
+ *
+ * Like strscpy(), only for UCS2 strings.
+ *
+ * Copy the source string @src, or as much of it as fits, into the destination
+ * buffer @dst. The behavior is undefined if the string buffers overlap. The
+ * destination buffer @dst is always NUL-terminated, unless it's zero-sized.
+ *
+ * Return: The number of characters copied into @dst (excluding the trailing
+ * %NUL terminator) or -E2BIG if @count is 0 or @src was truncated due to the
+ * destination buffer being too small.
+ */
+ssize_t ucs2_strscpy(ucs2_char_t *dst, const ucs2_char_t *src, size_t count)
+{
+ long res;
+
+ /*
+ * Ensure that we have a valid amount of space. We need to store at
+ * least one NUL-character.
+ */
+ if (count == 0 || WARN_ON_ONCE(count > INT_MAX / sizeof(*dst)))
+ return -E2BIG;
+
+ /*
+ * Copy at most 'count' characters, return early if we find a
+ * NUL-terminator.
+ */
+ for (res = 0; res < count; res++) {
+ ucs2_char_t c;
+
+ c = src[res];
+ dst[res] = c;
+
+ if (!c)
+ return res;
+ }
+
+ /*
+ * The loop above terminated without finding a NUL-terminator,
+ * exceeding the 'count': Enforce proper NUL-termination and return
+ * error.
+ */
+ dst[count - 1] = 0;
+ return -E2BIG;
+}
+EXPORT_SYMBOL(ucs2_strscpy);
+
int
ucs2_strncmp(const ucs2_char_t *a, const ucs2_char_t *b, size_t len)
{
--
2.42.0
next prev parent reply other threads:[~2023-08-27 21:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-27 21:14 [PATCH v6 0/3] firmware: Add support for Qualcomm UEFI Secure Application Maximilian Luz
2023-08-27 21:14 ` Maximilian Luz [this message]
2023-08-27 21:14 ` [PATCH v6 2/3] firmware: qcom_scm: Add support for Qualcomm Secure Execution Environment SCM interface Maximilian Luz
2023-08-27 21:14 ` [PATCH v6 3/3] firmware: Add support for Qualcomm UEFI Secure Application Maximilian Luz
2023-08-27 21:26 ` Trilok Soni
2023-08-27 21:53 ` Maximilian Luz
2023-08-27 21:59 ` Trilok Soni
2023-09-07 20:52 ` Maximilian Luz
2023-09-07 22:05 ` Trilok Soni
2023-09-07 20:40 ` Bjorn Andersson
2023-09-14 16:04 ` [PATCH v6 0/3] " Bjorn Andersson
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