This series introduces a family of generic string case conversion functions. This kind of functionality is needed in several places in the kernel. Right now, everybody seems to be implementing their own copy of this functionality.
Based on the discussion of the previous version of this series[1] and the use cases found in the kernel, it does look like having several flavours of case conversion functions is beneficial. The use cases fall into three categories: - copying a string and converting the case while specifying a maximum length to mimic strlcpy() - copying a string and converting the case without specifying a length to mimic strcpy() - converting the case of a string in-place (i.e. modifying the string that was passed in)
Consequently, I am proposing these new functions: int strlcpytoupper(char *dst, const char *src, size_t len); int strlcpytolower(char *dst, const char *src, size_t len); void strcpytoupper(char *dst, const char *src); void strcpytolower(char *dst, const char *src); void strtoupper(char *s); void strtolower(char *s);
Several drivers are being modified to make use of the functions above. Another driver that also makes use of this functionality will be submitted upstream shortly, which prompted this whole exercise.
The changes made here have been compile-tested, but not tried out, due to lack of required hardware.
Changes since v4: - rebased on 4.8-rc1; this only affects patch 6/7 (gk104) and only the patch context, not the patch itself - added an ACK to patch 4/7 (speakup) - added an ACK to patch 7/7 (power_supply)
Changes since v3: - strlcpytoupper() and strlcpytolower() return length of destination or -E2BIG (see [2]) - we use ~(size_t)0 instead of -1 to copy strings of arbitrary length in strcpyto*() and strto*() - A few ACKs added
Changes since v2: - use strlcpy() semantics not strncpy() semantics, i.e. guarantee NULL termination - as a result strncpyto<upper|lower> are now called strlcpyto<upper|lower> - make functions void - use len == -1 (SIZE_MAX) as no-limit indicator rather then len == 0 - change PATCH 2/7 to match strlcpy() semantics - change PATCH 4/7 to match strlcpy() semantics
Changes since v1: - expanded strtolower() into a family of functions that cover use cases when a length argument is or isn't required and that support copying the string into a new buffer or changing it in-place - changed the function semantics to return a pointer to the terminating '\0' character of the modified string - added strtoupper() functionality mirroring the above - dropped the ACPICA patch, since that code is OS independent and can't rely on a Linux library function (see [3]) - Added two new patches replacing strtoupper() implementations
[1] https://lkml.org/lkml/2016/6/30/727 [2] https://lkml.org/lkml/2016/7/10/4 [3] https://lkml.org/lkml/2016/7/1/9
Markus Mayer (7): lib: string: add functions to case-convert strings drm/nouveau/core: make use of new strlcpytolower() function ACPI / device_sysfs: make use of new strtolower() function staging: speakup: replace spk_strlwr() with strlcpytolower() iscsi-target: replace iscsi_initiatorname_tolower() with strtolower() drm/nouveau/fifo/gk104: make use of new strcpytoupper() function power_supply: make use of new strcpytoupper() function
drivers/acpi/device_sysfs.c | 4 +-- drivers/gpu/drm/nouveau/nvkm/core/firmware.c | 9 +---- drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c | 5 +-- drivers/power/power_supply_sysfs.c | 13 +++---- drivers/staging/speakup/kobjects.c | 3 +- drivers/staging/speakup/main.c | 3 +- drivers/staging/speakup/speakup.h | 1 - drivers/staging/speakup/varhandlers.c | 12 ------- drivers/target/iscsi/iscsi_target_nego.c | 17 +-------- include/linux/string.h | 40 +++++++++++++++++++++ lib/string.c | 46 ++++++++++++++++++++++++ 11 files changed, 98 insertions(+), 55 deletions(-)
Add a collection of generic functions to convert strings to lowercase or uppercase.
Changing the case of a string (with or without copying it first) seems to be a recurring requirement in the kernel that is currently being solved by several duplicated implementations doing the same thing. This change aims at reducing this code duplication.
The new functions are int strlcpytoupper(char *dst, const char *src, size_t len); int strlcpytolower(char *dst, const char *src, size_t len); void strcpytoupper(char *dst, const char *src); void strcpytolower(char *dst, const char *src); void strtoupper(char *s); void strtolower(char *s);
The "str[l]cpyto*" versions of the function take a destination string and a source string as arguments. The "strlcpyto*" versions additionally take a length argument like strlcpy() itself. Lastly, the strto* functions take a single string argument and modify the passed-in string.
strlcpytoupper() and strlcpytolower() return the number of characters copied or -E2BIG if the destination string was truncated.
Like strlcpy(), and unlike strncpy(), the functions guarantee NULL termination of the destination string.
Signed-off-by: Markus Mayer mmayer@broadcom.com --- include/linux/string.h | 40 ++++++++++++++++++++++++++++++++++++++++ lib/string.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+)
diff --git a/include/linux/string.h b/include/linux/string.h index 26b6f6a..257d797 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -116,6 +116,8 @@ extern void * memchr(const void *,int,__kernel_size_t); #endif void *memchr_inv(const void *s, int c, size_t n); char *strreplace(char *s, char old, char new); +extern int strlcpytoupper(char *dst, const char *src, size_t len); +extern int strlcpytolower(char *dst, const char *src, size_t len);
extern void kfree_const(const void *x);
@@ -169,4 +171,42 @@ static inline const char *kbasename(const char *path) return tail ? tail + 1 : path; }
+/** + * strcpytoupper - Copy string and convert to uppercase. + * @dst: The buffer to store the result. + * @src: The string to convert to uppercase. + */ +static inline void strcpytoupper(char *dst, const char *src) +{ + strlcpytoupper(dst, src, ~(size_t)0); +} + +/** + * strcpytolower - Copy string and convert to lowercase. + * @dst: The buffer to store the result. + * @src: The string to convert to lowercase. + */ +static inline void strcpytolower(char *dst, const char *src) +{ + strlcpytolower(dst, src, ~(size_t)0); +} + +/** + * strtoupper - Convert string to uppercase. + * @s: The string to operate on. + */ +static inline void strtoupper(char *s) +{ + strlcpytoupper(s, s, ~(size_t)0); +} + +/** + * strtolower - Convert string to lowercase. + * @s: The string to operate on. + */ +static inline void strtolower(char *s) +{ + strlcpytolower(s, s, ~(size_t)0); +} + #endif /* _LINUX_STRING_H_ */ diff --git a/lib/string.c b/lib/string.c index ed83562..d36d5fb2 100644 --- a/lib/string.c +++ b/lib/string.c @@ -952,3 +952,49 @@ char *strreplace(char *s, char old, char new) return s; } EXPORT_SYMBOL(strreplace); + +/** + * strlcpytoupper - Copy a length-limited string and convert to uppercase. + * @dst: The buffer to store the result. + * @src: The string to convert to uppercase. + * @len: Maximum string length. May be SIZE_MAX to set no limit. + * + * Returns the number of characters copied or -E2BIG if @dst wasn't big enough. + */ +int strlcpytoupper(char *dst, const char *src, size_t len) +{ + size_t i; + + if (!len) + return -E2BIG; + + for (i = 0; i < len && src[i]; ++i) + dst[i] = toupper(src[i]); + dst[i < len ? i : i - 1] = '\0'; + + return (i < len) ? i : -E2BIG; +} +EXPORT_SYMBOL(strlcpytoupper); + +/** + * strlcpytolower - Copy a length-limited string and convert to lowercase. + * @dst: The buffer to store the result. + * @src: The string to convert to lowercase. + * @len: Maximum string length. May be SIZE_MAX to set no limit. + * + * Returns the number of characters copied or -E2BIG if @dst wasn't big enough. + */ +int strlcpytolower(char *dst, const char *src, size_t len) +{ + size_t i; + + if (!len) + return -E2BIG; + + for (i = 0; i < len && src[i]; ++i) + dst[i] = tolower(src[i]); + dst[i < len ? i : i - 1] = '\0'; + + return (i < len) ? i : -E2BIG; +} +EXPORT_SYMBOL(strlcpytolower);
Call strlcpytolower() rather than copying the string explicitly and then walking it to convert it to lowercase.
Signed-off-by: Markus Mayer mmayer@broadcom.com --- drivers/gpu/drm/nouveau/nvkm/core/firmware.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c index 34ecd4a..982601e 100644 --- a/drivers/gpu/drm/nouveau/nvkm/core/firmware.c +++ b/drivers/gpu/drm/nouveau/nvkm/core/firmware.c @@ -36,16 +36,9 @@ nvkm_firmware_get(struct nvkm_device *device, const char *fwname, { char f[64]; char cname[16]; - int i;
/* Convert device name to lowercase */ - strncpy(cname, device->chip->name, sizeof(cname)); - cname[sizeof(cname) - 1] = '\0'; - i = strlen(cname); - while (i) { - --i; - cname[i] = tolower(cname[i]); - } + strlcpytolower(cname, device->chip->name, sizeof(cname));
snprintf(f, sizeof(f), "nvidia/%s/%s.bin", cname, fwname); return request_firmware(fw, f, device->dev);
Call strcpytoupper() rather than copying the string explicitly and then walking it to convert it to uppercase.
Signed-off-by: Markus Mayer mmayer@broadcom.com --- drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c index 103c0af..24f4c45 100644 --- a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c +++ b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c @@ -332,10 +332,7 @@ gk104_fifo_intr_fault(struct gk104_fifo *fifo, int unit) enum nvkm_devidx engidx = nvkm_top_fault(device, unit); if (engidx < NVKM_SUBDEV_NR) { const char *src = nvkm_subdev_name[engidx]; - char *dst = en; - do { - *dst++ = toupper(*src++); - } while(*src); + strcpytoupper(en, src); engine = nvkm_device_engine(device, engidx); } } else {
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Markus Mayer