third_party/ulib/musl/src/passwd/getgrouplist.c

#define _GNU_SOURCE
#include "nscd.h"
#include "pwf.h"
#include <byteswap.h>
#include <errno.h>
#include <grp.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int getgrouplist(const char* user, gid_t gid, gid_t* groups, int* ngroups) {
    int rv, nlim, ret = -1;
    ssize_t i, n = 1;
    struct group gr;
    struct group* res;
    FILE* f;
    int swap = 0;
    int32_t resp[INITGR_LEN];
    uint32_t* nscdbuf = 0;
    char* buf = 0;
    char** mem = 0;
    size_t nmem = 0;
    size_t size;
    nlim = *ngroups;
    if (nlim >= 1)
        *groups++ = gid;

    f = __nscd_query(GETINITGR, user, resp, sizeof resp, &swap);
    if (!f)
        goto cleanup;
    if (resp[INITGRFOUND]) {
        nscdbuf = calloc(resp[INITGRNGRPS], sizeof(uint32_t));
        if (!nscdbuf)
            goto cleanup;
        if (!fread(nscdbuf, sizeof(*nscdbuf) * resp[INITGRNGRPS], 1, f)) {
            if (!ferror(f))
                errno = EIO;
            goto cleanup;
        }
        if (swap) {
            for (i = 0; i < resp[INITGRNGRPS]; i++)
                nscdbuf[i] = bswap_32(nscdbuf[i]);
        }
    }
    fclose(f);

    f = fopen("/etc/group", "rbe");
    if (!f && errno != ENOENT && errno != ENOTDIR)
        goto cleanup;

    if (f) {
        while (!(rv = __getgrent_a(f, &gr, &buf, &size, &mem, &nmem, &res)) && res) {
            if (nscdbuf)
                for (i = 0; i < resp[INITGRNGRPS]; i++) {
                    if (nscdbuf[i] == gr.gr_gid)
                        nscdbuf[i] = gid;
                }
            for (i = 0; gr.gr_mem[i] && strcmp(user, gr.gr_mem[i]); i++)
                ;
            if (!gr.gr_mem[i])
                continue;
            if (++n <= nlim)
                *groups++ = gr.gr_gid;
        }
        if (rv) {
            errno = rv;
            goto cleanup;
        }
    }
    if (nscdbuf) {
        for (i = 0; i < resp[INITGRNGRPS]; i++) {
            if (nscdbuf[i] != gid)
                if (++n <= nlim)
                    *groups++ = nscdbuf[i];
        }
    }

    ret = n > nlim ? -1 : n;
    *ngroups = n;

cleanup:
    if (f)
        fclose(f);
    free(nscdbuf);
    free(buf);
    free(mem);
    return ret;
}