setgroups.c

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/*
setgroups.c
*/

#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <grp.h>

int setgroups(int ngroups, const gid_t *gidset)
{
        if(ngroups > 1) {
                /* Supplementary groups not implemented */
                errno= EINVAL;
                return -1;
        }

        if(ngroups == 1)
                return setgid(gidset[0]);

        return 0;
}

int initgroups(const char *name, gid_t basegid)
{
        struct group *gr;
        int r, found = 0;
        if((r = setgid(basegid)) < 0)
                return r;

        setgrent();
        while (!found && (gr = getgrent()) != NULL) {
                char **mem;
                for(mem = gr->gr_mem; mem && *mem; mem++) {
                        if(!strcmp(name, *mem)) {
                                found = 1;
                                break;
                        }
                }
        }
        endgrent();

        /* Because supplemental groups aren't implemented, this call
         * should fail if the user is in any supplemental groups.
         */
        if(found) {
                errno = EINVAL;
                return -1;
        }

        return 0;
}

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