The logic to find the whole matching name was split needlessly between the reverse_strstr function and its caller. Fully contain it to make the interface for calling it more consistent.
Signed-off-by: Joe Hershberger joe.hershberger@ni.com
---
Changes in v2: -Fix bisectability issue -Fix corner case in reverse_name_search() where searched starts with ' '
common/env_attr.c | 87 ++++++++++++++++++++++++++++++------------------------- 1 file changed, 47 insertions(+), 40 deletions(-)
diff --git a/common/env_attr.c b/common/env_attr.c index e791f44..6e13184 100644 --- a/common/env_attr.c +++ b/common/env_attr.c @@ -109,33 +109,59 @@ int env_attr_walk(const char *attr_list, }
/* - * Search for the last matching string in another string with the option to - * start looking at a certain point (i.e. ignore anything beyond that point). + * Search for the last exactly matching name in an attribute list */ -static char *reverse_strstr(const char *searched, const char *search_for, - const char *searched_start) +static int reverse_name_search(const char *searched, const char *search_for, + const char **result) { - char *result = NULL; + int result_size = 0; + const char *cur_searched = searched;
- if (*search_for == '\0') - return (char *)searched; + if (result) + *result = NULL; + + if (*search_for == '\0') { + if (result) + *result = searched; + return strlen(searched); + }
for (;;) { - char *match = strstr(searched, search_for); - - /* - * Stop looking if no new match is found or looking past the - * searched_start pointer - */ - if (match == NULL || (searched_start != NULL && - match + strlen(search_for) > searched_start)) + const char *match = strstr(cur_searched, search_for); + const char *prevch; + const char *nextch; + + /* Stop looking if no new match is found */ + if (match == NULL) break;
- result = match; - searched = match + 1; + prevch = match - 1; + nextch = match + strlen(search_for); + + /* Skip spaces */ + while (*prevch == ' ' && prevch >= searched) + prevch--; + while (*nextch == ' ') + nextch++; + + /* Start looking past the current match so last is found */ + cur_searched = match + 1; + /* Check for an exact match */ + if (match != searched && + *prevch != ENV_ATTR_LIST_DELIM && + prevch != searched - 1) + continue; + if (*nextch != ENV_ATTR_SEP && + *nextch != ENV_ATTR_LIST_DELIM && + *nextch != '\0') + continue; + + if (result) + *result = match; + result_size = strlen(search_for); }
- return result; + return result_size; }
/* @@ -145,6 +171,7 @@ static char *reverse_strstr(const char *searched, const char *search_for, int env_attr_lookup(const char *attr_list, const char *name, char *attributes) { const char *entry = NULL; + int entry_len;
if (!attributes) /* bad parameter */ @@ -153,32 +180,12 @@ int env_attr_lookup(const char *attr_list, const char *name, char *attributes) /* list not found */ return -EINVAL;
- entry = reverse_strstr(attr_list, name, NULL); - while (entry != NULL) { - const char *prevch = entry - 1; - const char *nextch = entry + strlen(name); - - /* Skip spaces */ - while (*prevch == ' ') - prevch--; - while (*nextch == ' ') - nextch++; - - /* check for an exact match */ - if ((entry == attr_list || - *prevch == ENV_ATTR_LIST_DELIM) && - (*nextch == ENV_ATTR_SEP || - *nextch == ENV_ATTR_LIST_DELIM || - *nextch == '\0')) - break; - - entry = reverse_strstr(attr_list, name, entry); - } + entry_len = reverse_name_search(attr_list, name, &entry); if (entry != NULL) { int len;
/* skip the name */ - entry += strlen(name); + entry += entry_len; /* skip spaces */ while (*entry == ' ') entry++;