How to make the strtok working when reading the pathnames? - c

Question

In this code, I am trying to split the pathnames with the help of strtok(). I am watching the \n sign to differentiate different pathnames. Although when I print the path variable, it gives all the pathnames.
But when I split them and print the token[1] variable, it gives me the segmentation fault. I used token[0], but it gave me all the pathnames as it was printed with the path variable but without \n sign concatenated with pathnames.
int watch(char *dirname) {
DIR *dir;
struct dirent *entity;
char path[500] = { 0 };
char *token[2];
dir = opendir(dirname);
if (dir != NULL) {
while (entity = readdir(dir)) {
snprintf(path, sizeof(path), "%s%s", dirname, entity->d_name);
strcat(path, "\n");
token[0] = strtok(path, "\n");
token[1] = strtok(NULL, "\n");
printf("%s\n", token[1]);
}
closedir(dir);
} else {
perror("Couldn't open the directory");
}
}

Answer 1

The given code does not make sense and it is unclear what the real purpose is.
As it stands token[1] will always be NULL. As the string to tokenize is something like "dirfilename\n" and then split on \n. The second call to strtok always returns NULL.
So the question remains, what is the purpose of this code?

Answer 2

When concatenating the dirname and filename, you do not insert a / between them. Use "%s/%s" to make it a pathname.
It is unclear why there should be any ; in the pathname. This might be a confusion with the PATH variable.
Here is a simple program to enumerate files from the directories in the PATH variable:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <dirent.h>
int list_path(const char *p, int len) {
char path[1024];
DIR *dir;
struct dirent *entity;
int count = 0;
if (len + 2 > (int)sizeof(path))
return -1;
snprintf(path, sizeof(path), "%.*s", len, p);
dir = opendir(path);
if (dir != NULL) {
while ((entity = readdir(dir)) != NULL) {
if (!strcmp(entity->d_name, ".") || !strcmp(entity->d_name, ".."))
continue;
count++;
snprintf(path + len, sizeof(path) - len, "/%s", entity->d_name);
printf("%s\n", path);
}
closedir(dir);
}
return count;
}
int main() {
char *path = getenv("PATH");
const char *pathsep = ":"; // use `;` for Windows
int len;
if (path) {
while (*path) {
len = strcspn(path, pathsep);
list_path(path, len);
path += len + (path[len] != '\0');
}
}
return 0;
}