diff options
Diffstat (limited to 'lib/string_helpers.c')
| -rw-r--r-- | lib/string_helpers.c | 538 |
1 files changed, 480 insertions, 58 deletions
diff --git a/lib/string_helpers.c b/lib/string_helpers.c index 4403e1924f73..7713f73e66b0 100644 --- a/lib/string_helpers.c +++ b/lib/string_helpers.c @@ -10,6 +10,7 @@ #include <linux/math64.h> #include <linux/export.h> #include <linux/ctype.h> +#include <linux/device.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/limits.h> @@ -30,9 +31,11 @@ * giving the size in the required units. @buf should have room for * at least 9 bytes and will always be zero terminated. * + * Return value: number of characters of output that would have been written + * (which may be greater than len, if output was truncated). */ -void string_get_size(u64 size, u64 blk_size, const enum string_size_units units, - char *buf, int len) +int string_get_size(u64 size, u64 blk_size, const enum string_size_units units, + char *buf, int len) { static const char *const units_10[] = { "B", "kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB" @@ -125,11 +128,55 @@ void string_get_size(u64 size, u64 blk_size, const enum string_size_units units, else unit = units_str[units][i]; - snprintf(buf, len, "%u%s %s", (u32)size, - tmp, unit); + return snprintf(buf, len, "%u%s %s", (u32)size, + tmp, unit); } EXPORT_SYMBOL(string_get_size); +/** + * parse_int_array_user - Split string into a sequence of integers + * @from: The user space buffer to read from + * @count: The maximum number of bytes to read + * @array: Returned pointer to sequence of integers + * + * On success @array is allocated and initialized with a sequence of + * integers extracted from the @from plus an additional element that + * begins the sequence and specifies the integers count. + * + * Caller takes responsibility for freeing @array when it is no longer + * needed. + */ +int parse_int_array_user(const char __user *from, size_t count, int **array) +{ + int *ints, nints; + char *buf; + int ret = 0; + + buf = memdup_user_nul(from, count); + if (IS_ERR(buf)) + return PTR_ERR(buf); + + get_options(buf, 0, &nints); + if (!nints) { + ret = -ENOENT; + goto free_buf; + } + + ints = kcalloc(nints + 1, sizeof(*ints), GFP_KERNEL); + if (!ints) { + ret = -ENOMEM; + goto free_buf; + } + + get_options(buf, nints + 1, ints); + *array = ints; + +free_buf: + kfree(buf); + return ret; +} +EXPORT_SYMBOL(parse_int_array_user); + static bool unescape_space(char **src, char **dst) { char *p = *dst, *q = *src; @@ -231,35 +278,36 @@ static bool unescape_special(char **src, char **dst) * @src: source buffer (escaped) * @dst: destination buffer (unescaped) * @size: size of the destination buffer (0 to unlimit) - * @flags: combination of the flags (bitwise OR): - * %UNESCAPE_SPACE: + * @flags: combination of the flags. + * + * Description: + * The function unquotes characters in the given string. + * + * Because the size of the output will be the same as or less than the size of + * the input, the transformation may be performed in place. + * + * Caller must provide valid source and destination pointers. Be aware that + * destination buffer will always be NULL-terminated. Source string must be + * NULL-terminated as well. The supported flags are:: + * + * UNESCAPE_SPACE: * '\f' - form feed * '\n' - new line * '\r' - carriage return * '\t' - horizontal tab * '\v' - vertical tab - * %UNESCAPE_OCTAL: + * UNESCAPE_OCTAL: * '\NNN' - byte with octal value NNN (1 to 3 digits) - * %UNESCAPE_HEX: + * UNESCAPE_HEX: * '\xHH' - byte with hexadecimal value HH (1 to 2 digits) - * %UNESCAPE_SPECIAL: + * UNESCAPE_SPECIAL: * '\"' - double quote * '\\' - backslash * '\a' - alert (BEL) * '\e' - escape - * %UNESCAPE_ANY: + * UNESCAPE_ANY: * all previous together * - * Description: - * The function unquotes characters in the given string. - * - * Because the size of the output will be the same as or less than the size of - * the input, the transformation may be performed in place. - * - * Caller must provide valid source and destination pointers. Be aware that - * destination buffer will always be NULL-terminated. Source string must be - * NULL-terminated as well. - * * Return: * The amount of the characters processed to the destination buffer excluding * trailing '\0' is returned. @@ -360,6 +408,9 @@ static bool escape_special(unsigned char c, char **dst, char *end) case '\e': to = 'e'; break; + case '"': + to = '"'; + break; default: return false; } @@ -441,7 +492,31 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * @isz: source buffer size * @dst: destination buffer (escaped) * @osz: destination buffer size - * @flags: combination of the flags (bitwise OR): + * @flags: combination of the flags + * @only: NULL-terminated string containing characters used to limit + * the selected escape class. If characters are included in @only + * that would not normally be escaped by the classes selected + * in @flags, they will be copied to @dst unescaped. + * + * Description: + * The process of escaping byte buffer includes several parts. They are applied + * in the following sequence. + * + * 1. The character is not matched to the one from @only string and thus + * must go as-is to the output. + * 2. The character is matched to the printable and ASCII classes, if asked, + * and in case of match it passes through to the output. + * 3. The character is matched to the printable or ASCII class, if asked, + * and in case of match it passes through to the output. + * 4. The character is checked if it falls into the class given by @flags. + * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any + * character. Note that they actually can't go together, otherwise + * %ESCAPE_HEX will be ignored. + * + * Caller must provide valid source and destination pointers. Be aware that + * destination buffer will not be NULL-terminated, thus caller have to append + * it if needs. The supported flags are:: + * * %ESCAPE_SPACE: (special white space, not space itself) * '\f' - form feed * '\n' - new line @@ -449,6 +524,7 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * '\t' - horizontal tab * '\v' - vertical tab * %ESCAPE_SPECIAL: + * '\"' - double quote * '\\' - backslash * '\a' - alert (BEL) * '\e' - escape @@ -459,31 +535,27 @@ static bool escape_hex(unsigned char c, char **dst, char *end) * %ESCAPE_ANY: * all previous together * %ESCAPE_NP: - * escape only non-printable characters (checked by isprint) + * escape only non-printable characters, checked by isprint() * %ESCAPE_ANY_NP: * all previous together * %ESCAPE_HEX: * '\xHH' - byte with hexadecimal value HH (2 digits) - * @only: NULL-terminated string containing characters used to limit - * the selected escape class. If characters are included in @only - * that would not normally be escaped by the classes selected - * in @flags, they will be copied to @dst unescaped. + * %ESCAPE_NA: + * escape only non-ascii characters, checked by isascii() + * %ESCAPE_NAP: + * escape only non-printable or non-ascii characters + * %ESCAPE_APPEND: + * append characters from @only to be escaped by the given classes * - * Description: - * The process of escaping byte buffer includes several parts. They are applied - * in the following sequence. - * 1. The character is matched to the printable class, if asked, and in - * case of match it passes through to the output. - * 2. The character is not matched to the one from @only string and thus - * must go as-is to the output. - * 3. The character is checked if it falls into the class given by @flags. - * %ESCAPE_OCTAL and %ESCAPE_HEX are going last since they cover any - * character. Note that they actually can't go together, otherwise - * %ESCAPE_HEX will be ignored. + * %ESCAPE_APPEND would help to pass additional characters to the escaped, when + * one of %ESCAPE_NP, %ESCAPE_NA, or %ESCAPE_NAP is provided. * - * Caller must provide valid source and destination pointers. Be aware that - * destination buffer will not be NULL-terminated, thus caller have to append - * it if needs. + * One notable caveat, the %ESCAPE_NAP, %ESCAPE_NP and %ESCAPE_NA have the + * higher priority than the rest of the flags (%ESCAPE_NAP is the highest). + * It doesn't make much sense to use either of them without %ESCAPE_OCTAL + * or %ESCAPE_HEX, because they cover most of the other character classes. + * %ESCAPE_NAP can utilize %ESCAPE_SPACE or %ESCAPE_SPECIAL in addition to + * the above. * * Return: * The total size of the escaped output that would be generated for @@ -497,41 +569,62 @@ int string_escape_mem(const char *src, size_t isz, char *dst, size_t osz, char *p = dst; char *end = p + osz; bool is_dict = only && *only; + bool is_append = flags & ESCAPE_APPEND; while (isz--) { unsigned char c = *src++; + bool in_dict = is_dict && strchr(only, c); /* * Apply rules in the following sequence: - * - the character is printable, when @flags has - * %ESCAPE_NP bit set * - the @only string is supplied and does not contain a * character under question + * - the character is printable and ASCII, when @flags has + * %ESCAPE_NAP bit set + * - the character is printable, when @flags has + * %ESCAPE_NP bit set + * - the character is ASCII, when @flags has + * %ESCAPE_NA bit set * - the character doesn't fall into a class of symbols * defined by given @flags * In these cases we just pass through a character to the * output buffer. + * + * When %ESCAPE_APPEND is passed, the characters from @only + * have been excluded from the %ESCAPE_NAP, %ESCAPE_NP, and + * %ESCAPE_NA cases. */ - if ((flags & ESCAPE_NP && isprint(c)) || - (is_dict && !strchr(only, c))) { - /* do nothing */ - } else { - if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) - continue; + if (!(is_append || in_dict) && is_dict && + escape_passthrough(c, &p, end)) + continue; - if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end)) - continue; + if (!(is_append && in_dict) && isascii(c) && isprint(c) && + flags & ESCAPE_NAP && escape_passthrough(c, &p, end)) + continue; - if (flags & ESCAPE_NULL && escape_null(c, &p, end)) - continue; + if (!(is_append && in_dict) && isprint(c) && + flags & ESCAPE_NP && escape_passthrough(c, &p, end)) + continue; - /* ESCAPE_OCTAL and ESCAPE_HEX always go last */ - if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) - continue; + if (!(is_append && in_dict) && isascii(c) && + flags & ESCAPE_NA && escape_passthrough(c, &p, end)) + continue; - if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) - continue; - } + if (flags & ESCAPE_SPACE && escape_space(c, &p, end)) + continue; + + if (flags & ESCAPE_SPECIAL && escape_special(c, &p, end)) + continue; + + if (flags & ESCAPE_NULL && escape_null(c, &p, end)) + continue; + + /* ESCAPE_OCTAL and ESCAPE_HEX always go last */ + if (flags & ESCAPE_OCTAL && escape_octal(c, &p, end)) + continue; + + if (flags & ESCAPE_HEX && escape_hex(c, &p, end)) + continue; escape_passthrough(c, &p, end); } @@ -627,3 +720,332 @@ char *kstrdup_quotable_file(struct file *file, gfp_t gfp) return pathname; } EXPORT_SYMBOL_GPL(kstrdup_quotable_file); + +/* + * Returns duplicate string in which the @old characters are replaced by @new. + */ +char *kstrdup_and_replace(const char *src, char old, char new, gfp_t gfp) +{ + char *dst; + + dst = kstrdup(src, gfp); + if (!dst) + return NULL; + + return strreplace(dst, old, new); +} +EXPORT_SYMBOL_GPL(kstrdup_and_replace); + +/** + * kasprintf_strarray - allocate and fill array of sequential strings + * @gfp: flags for the slab allocator + * @prefix: prefix to be used + * @n: amount of lines to be allocated and filled + * + * Allocates and fills @n strings using pattern "%s-%zu", where prefix + * is provided by caller. The caller is responsible to free them with + * kfree_strarray() after use. + * + * Returns array of strings or NULL when memory can't be allocated. + */ +char **kasprintf_strarray(gfp_t gfp, const char *prefix, size_t n) +{ + char **names; + size_t i; + + names = kcalloc(n + 1, sizeof(char *), gfp); + if (!names) + return NULL; + + for (i = 0; i < n; i++) { + names[i] = kasprintf(gfp, "%s-%zu", prefix, i); + if (!names[i]) { + kfree_strarray(names, i); + return NULL; + } + } + + return names; +} +EXPORT_SYMBOL_GPL(kasprintf_strarray); + +/** + * kfree_strarray - free a number of dynamically allocated strings contained + * in an array and the array itself + * + * @array: Dynamically allocated array of strings to free. + * @n: Number of strings (starting from the beginning of the array) to free. + * + * Passing a non-NULL @array and @n == 0 as well as NULL @array are valid + * use-cases. If @array is NULL, the function does nothing. + */ +void kfree_strarray(char **array, size_t n) +{ + unsigned int i; + + if (!array) + return; + + for (i = 0; i < n; i++) + kfree(array[i]); + kfree(array); +} +EXPORT_SYMBOL_GPL(kfree_strarray); + +struct strarray { + char **array; + size_t n; +}; + +static void devm_kfree_strarray(struct device *dev, void *res) +{ + struct strarray *array = res; + + kfree_strarray(array->array, array->n); +} + +char **devm_kasprintf_strarray(struct device *dev, const char *prefix, size_t n) +{ + struct strarray *ptr; + + ptr = devres_alloc(devm_kfree_strarray, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return ERR_PTR(-ENOMEM); + + ptr->array = kasprintf_strarray(GFP_KERNEL, prefix, n); + if (!ptr->array) { + devres_free(ptr); + return ERR_PTR(-ENOMEM); + } + + ptr->n = n; + devres_add(dev, ptr); + + return ptr->array; +} +EXPORT_SYMBOL_GPL(devm_kasprintf_strarray); + +/** + * strscpy_pad() - Copy a C-string into a sized buffer + * @dest: Where to copy the string to + * @src: Where to copy the string from + * @count: Size of destination buffer + * + * Copy the string, or as much of it as fits, into the dest buffer. The + * behavior is undefined if the string buffers overlap. The destination + * buffer is always %NUL terminated, unless it's zero-sized. + * + * If the source string is shorter than the destination buffer, zeros + * the tail of the destination buffer. + * + * For full explanation of why you may want to consider using the + * 'strscpy' functions please see the function docstring for strscpy(). + * + * Returns: + * * The number of characters copied (not including the trailing %NUL) + * * -E2BIG if count is 0 or @src was truncated. + */ +ssize_t strscpy_pad(char *dest, const char *src, size_t count) +{ + ssize_t written; + + written = strscpy(dest, src, count); + if (written < 0 || written == count - 1) + return written; + + memset(dest + written + 1, 0, count - written - 1); + + return written; +} +EXPORT_SYMBOL(strscpy_pad); + +/** + * skip_spaces - Removes leading whitespace from @str. + * @str: The string to be stripped. + * + * Returns a pointer to the first non-whitespace character in @str. + */ +char *skip_spaces(const char *str) +{ + while (isspace(*str)) + ++str; + return (char *)str; +} +EXPORT_SYMBOL(skip_spaces); + +/** + * strim - Removes leading and trailing whitespace from @s. + * @s: The string to be stripped. + * + * Note that the first trailing whitespace is replaced with a %NUL-terminator + * in the given string @s. Returns a pointer to the first non-whitespace + * character in @s. + */ +char *strim(char *s) +{ + size_t size; + char *end; + + size = strlen(s); + if (!size) + return s; + + end = s + size - 1; + while (end >= s && isspace(*end)) + end--; + *(end + 1) = '\0'; + + return skip_spaces(s); +} +EXPORT_SYMBOL(strim); + +/** + * sysfs_streq - return true if strings are equal, modulo trailing newline + * @s1: one string + * @s2: another string + * + * This routine returns true iff two strings are equal, treating both + * NUL and newline-then-NUL as equivalent string terminations. It's + * geared for use with sysfs input strings, which generally terminate + * with newlines but are compared against values without newlines. + */ +bool sysfs_streq(const char *s1, const char *s2) +{ + while (*s1 && *s1 == *s2) { + s1++; + s2++; + } + + if (*s1 == *s2) + return true; + if (!*s1 && *s2 == '\n' && !s2[1]) + return true; + if (*s1 == '\n' && !s1[1] && !*s2) + return true; + return false; +} +EXPORT_SYMBOL(sysfs_streq); + +/** + * match_string - matches given string in an array + * @array: array of strings + * @n: number of strings in the array or -1 for NULL terminated arrays + * @string: string to match with + * + * This routine will look for a string in an array of strings up to the + * n-th element in the array or until the first NULL element. + * + * Historically the value of -1 for @n, was used to search in arrays that + * are NULL terminated. However, the function does not make a distinction + * when finishing the search: either @n elements have been compared OR + * the first NULL element was found. + * + * Return: + * index of a @string in the @array if matches, or %-EINVAL otherwise. + */ +int match_string(const char * const *array, size_t n, const char *string) +{ + int index; + const char *item; + + for (index = 0; index < n; index++) { + item = array[index]; + if (!item) + break; + if (!strcmp(item, string)) + return index; + } + + return -EINVAL; +} +EXPORT_SYMBOL(match_string); + +/** + * __sysfs_match_string - matches given string in an array + * @array: array of strings + * @n: number of strings in the array or -1 for NULL terminated arrays + * @str: string to match with + * + * Returns index of @str in the @array or -EINVAL, just like match_string(). + * Uses sysfs_streq instead of strcmp for matching. + * + * This routine will look for a string in an array of strings up to the + * n-th element in the array or until the first NULL element. + * + * Historically the value of -1 for @n, was used to search in arrays that + * are NULL terminated. However, the function does not make a distinction + * when finishing the search: either @n elements have been compared OR + * the first NULL element was found. + */ +int __sysfs_match_string(const char * const *array, size_t n, const char *str) +{ + const char *item; + int index; + + for (index = 0; index < n; index++) { + item = array[index]; + if (!item) + break; + if (sysfs_streq(item, str)) + return index; + } + + return -EINVAL; +} +EXPORT_SYMBOL(__sysfs_match_string); + +/** + * strreplace - Replace all occurrences of character in string. + * @str: The string to operate on. + * @old: The character being replaced. + * @new: The character @old is replaced with. + * + * Replaces the each @old character with a @new one in the given string @str. + * + * Return: pointer to the string @str itself. + */ +char *strreplace(char *str, char old, char new) +{ + char *s = str; + + for (; *s; ++s) + if (*s == old) + *s = new; + return str; +} +EXPORT_SYMBOL(strreplace); + +/** + * memcpy_and_pad - Copy one buffer to another with padding + * @dest: Where to copy to + * @dest_len: The destination buffer size + * @src: Where to copy from + * @count: The number of bytes to copy + * @pad: Character to use for padding if space is left in destination. + */ +void memcpy_and_pad(void *dest, size_t dest_len, const void *src, size_t count, + int pad) +{ + if (dest_len > count) { + memcpy(dest, src, count); + memset(dest + count, pad, dest_len - count); + } else { + memcpy(dest, src, dest_len); + } +} +EXPORT_SYMBOL(memcpy_and_pad); + +#ifdef CONFIG_FORTIFY_SOURCE +/* These are placeholders for fortify compile-time warnings. */ +void __read_overflow2_field(size_t avail, size_t wanted) { } +EXPORT_SYMBOL(__read_overflow2_field); +void __write_overflow_field(size_t avail, size_t wanted) { } +EXPORT_SYMBOL(__write_overflow_field); + +void fortify_panic(const char *name) +{ + pr_emerg("detected buffer overflow in %s\n", name); + BUG(); +} +EXPORT_SYMBOL(fortify_panic); +#endif /* CONFIG_FORTIFY_SOURCE */ |