Viewing: string.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
* Copyright (c) 2012, 2017, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
*
* String manipulation functions.
*
* Author: Nathan Rutman <nathan.rutman@sun.com>
*/
#include <ctype.h>
#include <errno.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <unistd.h>
#include <libcfs/util/string.h>
/**
* Extracts tokens from strings.
*
* Looks for \a delim in string \a next, sets \a res to point to
* substring before the delimiter, sets \a next right after the found
* delimiter.
*
* \retval 1 if \a res points to a string of non-whitespace characters
* \retval 0 otherwise
*/
int
cfs_gettok(struct cfs_lstr *next, char delim, struct cfs_lstr *res)
{
char *end;
if (next->ls_str == NULL)
return 0;
/* skip leading white spaces */
while (next->ls_len) {
if (!isspace(*next->ls_str))
break;
next->ls_str++;
next->ls_len--;
}
if (next->ls_len == 0) /* whitespaces only */
return 0;
if (*next->ls_str == delim) {
/* first non-writespace is the delimiter */
return 0;
}
res->ls_str = next->ls_str;
end = memchr(next->ls_str, delim, next->ls_len);
if (end == NULL) {
/* there is no the delimeter in the string */
end = next->ls_str + next->ls_len;
next->ls_str = NULL;
next->ls_len = 0;
} else {
next->ls_str = end + 1;
next->ls_len -= (end - res->ls_str + 1);
}
/* skip ending whitespaces */
while (--end != res->ls_str) {
if (!isspace(*end))
break;
}
res->ls_len = end - res->ls_str + 1;
return 1;
}
/**
* Converts string to integer.
*
* Accepts decimal and hexadecimal number recordings.
*
* \retval 1 if first \a nob chars of \a str convert to decimal or
* hexadecimal integer in the range [\a min, \a max]
* \retval 0 otherwise
*/
int
cfs_str2num_check(char *str, int nob, unsigned *num,
unsigned min, unsigned max)
{
char *endp;
*num = strtoul(str, &endp, 0);
if (endp == str)
return 0;
for (; endp < str + nob; endp++) {
if (!isspace(*endp))
return 0;
}
return (*num >= min && *num <= max);
}
/**
* Parses \<range_expr\> token of the syntax. If \a bracketed is false,
* \a src should only have a single token which can be \<number\> or \*
*
* \retval pointer to allocated range_expr and initialized
* range_expr::re_lo, range_expr::re_hi and range_expr:re_stride if \a
* src parses to
* \<number\> |
* \<number\> '-' \<number\> |
* \<number\> '-' \<number\> '/' \<number\>
* \retval 0 will be returned if it can be parsed, otherwise -EINVAL or
* -ENOMEM will be returned.
*/
static int
cfs_range_expr_parse(struct cfs_lstr *src, unsigned min, unsigned max,
int bracketed, struct cfs_range_expr **expr)
{
struct cfs_range_expr *re;
struct cfs_lstr tok;
re = calloc(1, sizeof(*re));
if (re == NULL)
return -ENOMEM;
if (src->ls_len == 1 && src->ls_str[0] == '*') {
re->re_lo = min;
re->re_hi = max;
re->re_stride = 1;
goto out;
}
if (cfs_str2num_check(src->ls_str, src->ls_len,
&re->re_lo, min, max)) {
/* <number> is parsed */
re->re_hi = re->re_lo;
re->re_stride = 1;
goto out;
}
if (!bracketed || !cfs_gettok(src, '-', &tok))
goto failed;
if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
&re->re_lo, min, max))
goto failed;
/* <number> - */
if (cfs_str2num_check(src->ls_str, src->ls_len,
&re->re_hi, min, max)) {
/* <number> - <number> is parsed */
re->re_stride = 1;
goto out;
}
/* go to check <number> '-' <number> '/' <number> */
if (cfs_gettok(src, '/', &tok)) {
if (!cfs_str2num_check(tok.ls_str, tok.ls_len,
&re->re_hi, min, max))
goto failed;
/* <number> - <number> / ... */
if (cfs_str2num_check(src->ls_str, src->ls_len,
&re->re_stride, min, max)) {
/* <number> - <number> / <number> is parsed */
goto out;
}
}
out:
if (re->re_lo > re->re_hi)
goto failed;
*expr = re;
return 0;
failed:
free(re);
return -EINVAL;
}
/**
* Print the range expression \a re into specified \a buffer.
* If \a bracketed is true, expression does not need additional
* brackets.
*
* \retval number of characters written
*/
static int
cfs_range_expr_print(char *buffer, int count, struct cfs_range_expr *expr,
bool bracketed)
{
int i;
char s[] = "[";
char e[] = "]";
if (bracketed)
s[0] = e[0] = '\0';
if (expr->re_lo == expr->re_hi)
i = snprintf(buffer, count, "%u", expr->re_lo);
else if (expr->re_stride == 1)
i = snprintf(buffer, count, "%s%u-%u%s",
s, expr->re_lo, expr->re_hi, e);
else
i = snprintf(buffer, count, "%s%u-%u/%u%s",
s, expr->re_lo, expr->re_hi,
expr->re_stride, e);
return i;
}
/**
* Print a list of range expressions (\a expr_list) into specified \a buffer.
* If the list contains several expressions, separate them with comma
* and surround the list with brackets.
*
* \retval number of characters written
*/
int
cfs_expr_list_print(char *buffer, int count, struct cfs_expr_list *expr_list)
{
struct cfs_range_expr *expr;
int i = 0, j = 0;
int numexprs = 0;
if (count <= 0)
return 0;
list_for_each_entry(expr, &expr_list->el_exprs, re_link)
numexprs++;
if (numexprs > 1)
i += scnprintf(buffer + i, count - i, "[");
list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
if (j++ != 0)
i += scnprintf(buffer + i, count - i, ",");
i += cfs_range_expr_print(buffer + i, count - i, expr,
numexprs > 1);
}
if (numexprs > 1)
i += scnprintf(buffer + i, count - i, "]");
return i;
}
/**
* Convert express list (\a expr_list) to an array of all matched values
*
* \retval N N is total number of all matched values
* \retval 0 if expression list is empty
* \retval < 0 for failure
*/
int
cfs_expr_list_values(struct cfs_expr_list *expr_list, int max, __u32 **valpp)
{
struct cfs_range_expr *expr;
__u32 *val;
int count = 0;
int i;
list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
for (i = expr->re_lo; i <= expr->re_hi; i++) {
if (((i - expr->re_lo) % expr->re_stride) == 0)
count++;
}
}
if (count == 0) /* empty expression list */
return 0;
if (count > max)
return -EINVAL;
val = calloc(sizeof(val[0]), count);
if (val == NULL)
return -ENOMEM;
count = 0;
list_for_each_entry(expr, &expr_list->el_exprs, re_link) {
for (i = expr->re_lo; i <= expr->re_hi; i++) {
if (((i - expr->re_lo) % expr->re_stride) == 0)
val[count++] = i;
}
}
*valpp = val;
return count;
}
/**
* Frees cfs_range_expr structures of \a expr_list.
*
* \retval none
*/
void
cfs_expr_list_free(struct cfs_expr_list *expr_list)
{
while (!list_empty(&expr_list->el_exprs)) {
struct cfs_range_expr *expr;
expr = list_entry(expr_list->el_exprs.next,
struct cfs_range_expr, re_link);
list_del(&expr->re_link);
free(expr);
}
free(expr_list);
}
/**
* Parses \<cfs_expr_list\> token of the syntax.
*
* \retval 0 if \a str parses to \<number\> | \<expr_list\>
* \retval -errno otherwise
*/
int
cfs_expr_list_parse(char *str, int len, unsigned min, unsigned max,
struct cfs_expr_list **elpp)
{
struct cfs_expr_list *expr_list;
struct cfs_range_expr *expr;
struct cfs_lstr src;
int rc;
expr_list = calloc(1, sizeof(*expr_list));
if (expr_list == NULL)
return -ENOMEM;
src.ls_str = str;
src.ls_len = len;
INIT_LIST_HEAD(&expr_list->el_exprs);
if (src.ls_str[0] == '[' &&
src.ls_str[src.ls_len - 1] == ']') {
src.ls_str++;
src.ls_len -= 2;
rc = -EINVAL;
while (src.ls_str != NULL) {
struct cfs_lstr tok;
if (!cfs_gettok(&src, ',', &tok)) {
rc = -EINVAL;
break;
}
rc = cfs_range_expr_parse(&tok, min, max, 1, &expr);
if (rc != 0)
break;
list_add_tail(&expr->re_link,
&expr_list->el_exprs);
}
} else {
rc = cfs_range_expr_parse(&src, min, max, 0, &expr);
if (rc == 0) {
list_add_tail(&expr->re_link,
&expr_list->el_exprs);
}
}
if (rc != 0)
cfs_expr_list_free(expr_list);
else
*elpp = expr_list;
return rc;
}
/**
* Frees cfs_expr_list structures of \a list.
*
* For each struct cfs_expr_list structure found on \a list it frees
* range_expr list attached to it and frees the cfs_expr_list itself.
*
* \retval none
*/
void
cfs_expr_list_free_list(struct list_head *list)
{
struct cfs_expr_list *el;
while (!list_empty(list)) {
el = list_first_entry(list,
struct cfs_expr_list, el_link);
list_del(&el->el_link);
cfs_expr_list_free(el);
}
}
/**
* cfs_abs_path() - Get the absolute path of a relative path
* @request_path: The relative path to be resolved
* @resolved_path: Set to the resolved absolute path
*
* Returns the canonicalized absolute pathname. This function is a wrapper to
* realpath, but will work even if the target file does not exist. All
* directories in the path must exist.
*
* Return: On success, 0 is returned and resolved_path points to an allocated
* string containing the absolute pathname. On error, errno is set
* appropriately, -errno is returned, and resolved_path points to NULL.
*/
int cfs_abs_path(const char *request_path, char **resolved_path)
{
char buf[PATH_MAX + 1] = "";
char *path;
char *ptr;
int len;
int rc = 0;
const char *fmt;
path = malloc(sizeof(buf));
if (path == NULL)
return -ENOMEM;
if (request_path[0] != '/') {
if (getcwd(path, sizeof(buf) - 1) == NULL) {
rc = -errno;
goto out;
}
len = snprintf(buf, sizeof(buf), "%s/%s", path, request_path);
if (len >= sizeof(buf)) {
rc = -ENAMETOOLONG;
goto out;
}
} else {
/* skip duplicate leading '/' */
len = snprintf(buf, sizeof(buf), "%s",
request_path + strspn(request_path, "/") - 1);
if (len >= sizeof(buf)) {
rc = -ENAMETOOLONG;
goto out;
}
}
/* if filename not in root directory, call realpath for parent path */
ptr = strrchr(buf, '/');
if (ptr != buf) {
*ptr = '\0';
if (path != realpath(buf, path)) {
rc = -errno;
goto out;
}
/* add the filename back */
len = strlen(path);
fmt = (path[len - 1] == '/') ? "%s" : "/%s";
len = snprintf(path + len, sizeof(buf) - len, fmt, ptr + 1);
if (len >= sizeof(buf) - len) {
rc = -ENAMETOOLONG;
goto out;
}
} else {
len = snprintf(path, sizeof(buf), "%s", buf);
if (len >= sizeof(buf)) {
rc = -ENAMETOOLONG;
goto out;
}
}
out:
if (rc == 0) {
*resolved_path = path;
} else {
*resolved_path = NULL;
free(path);
}
return rc;
}
static char *skip_spaces(const char *str)
{
while (isspace(*str))
++str;
return (char *)str;
}
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);
}
