busybox/libpwdgrp/uidgid_get.c

#include "busybox.h"

int get_uidgid(struct bb_uidgid_t *u, const char *ug, int numeric_ok)
{
	struct passwd *pwd;
	struct group *gr;
	char *user, *group;
	unsigned n;

	user = (char*)ug;
	group = strchr(ug, ':');
	if (group) {
		int sz = (++group) - ug;
		user = alloca(sz);
		/* copies sz-1 bytes, stores terminating '\0' */
		safe_strncpy(user, ug, sz);
	}
	if (numeric_ok) {
		n = bb_strtou(user, NULL, 10);
		if (!errno) {
			u->uid = n;
			pwd = getpwuid(n);
			/* If we have e.g. "500" string without user */
			/* with uid 500 in /etc/passwd, we set gid == uid */
			u->gid = pwd ? pwd->pw_gid : n;
			goto skip;
		}
	}
	pwd = getpwnam(user);
	if (!pwd)
		return 0;
	u->uid = pwd->pw_uid;
	u->gid = pwd->pw_gid;

 skip:
	if (group) {
		if (numeric_ok) {
			n = bb_strtou(group, NULL, 10);
			if (!errno) {
				u->gid = n;
				return 1;
			}
		}
		gr = getgrnam(group);
		if (!gr) return 0;
		u->gid = gr->gr_gid;
	}
	return 1;
}

#if 0
#include <stdio.h>
int main()
{
	unsigned u;
	struct bb_uidgid_t ug;
	u = get_uidgid(&ug, "apache", 0);
	printf("%u = %u:%u\n", u, ug.uid, ug.gid);
	ug.uid = ug.gid = 1111;
	u = get_uidgid(&ug, "apache", 0);
	printf("%u = %u:%u\n", u, ug.uid, ug.gid);
	ug.uid = ug.gid = 1111;
	u = get_uidgid(&ug, "apache:users", 0);
	printf("%u = %u:%u\n", u, ug.uid, ug.gid);
	ug.uid = ug.gid = 1111;
	u = get_uidgid(&ug, "apache:users", 0);
	printf("%u = %u:%u\n", u, ug.uid, ug.gid);
	return 0;
}
#endif