c - Recursive mkdir() system call on Unix

Question

After reading the mkdir(2) man page for the Unix system call with that name, it appears that the call doesn't create intermediate directories in a path, only the last directory in the path. Is there any way (or other function) to create all the directories in the path without resorting to manually parsing my directory string and individually creating each directory ?

Answer 1

There is not a system call to do it for you, unfortunately. I'm guessing that's because there isn't a way to have really well-defined semantics for what should happen in error cases. Should it leave the directories that have already been created? Delete them? What if the deletions fail? And so on...

It is pretty easy to roll your own, however, and a quick google for 'recursive mkdir' turned up a number of solutions. Here's one that was near the top:

http://nion.modprobe.de/blog/archives/357-Recursive-directory-creation.html

static void _mkdir(const char *dir) {
    char tmp[256];
    char *p = NULL;
    size_t len;

    snprintf(tmp, sizeof(tmp),"%s",dir);
    len = strlen(tmp);
    if (tmp[len - 1] == '/')
        tmp[len - 1] = 0;
    for (p = tmp + 1; *p; p++)
        if (*p == '/') {
            *p = 0;
            mkdir(tmp, S_IRWXU);
            *p = '/';
        }
    mkdir(tmp, S_IRWXU);
}