fusl/src/passwd/getgrouplist.c

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