getgrouplist.c raw

   1  #define _GNU_SOURCE
   2  #include "pwf.h"
   3  #include <grp.h>
   4  #include <string.h>
   5  #include <limits.h>
   6  #include <stdio.h>
   7  #include <stdlib.h>
   8  #include <byteswap.h>
   9  #include <errno.h>
  10  #include "nscd.h"
  11  
  12  int getgrouplist(const char *user, gid_t gid, gid_t *groups, int *ngroups)
  13  {
  14  	int rv, nlim, ret = -1;
  15  	ssize_t i, n = 1;
  16  	struct group gr;
  17  	struct group *res;
  18  	FILE *f;
  19  	int swap = 0;
  20  	int32_t resp[INITGR_LEN];
  21  	uint32_t *nscdbuf = 0;
  22  	char *buf = 0;
  23  	char **mem = 0;
  24  	size_t nmem = 0;
  25  	size_t size;
  26  	nlim = *ngroups;
  27  	if (nlim >= 1) *groups++ = gid;
  28  
  29  	f = __nscd_query(GETINITGR, user, resp, sizeof resp, &swap);
  30  	if (!f) goto cleanup;
  31  	if (resp[INITGRFOUND]) {
  32  		nscdbuf = calloc(resp[INITGRNGRPS], sizeof(uint32_t));
  33  		if (!nscdbuf) goto cleanup;
  34  		size_t nbytes = sizeof(*nscdbuf)*resp[INITGRNGRPS];
  35  		if (nbytes && !fread(nscdbuf, nbytes, 1, f)) {
  36  			if (!ferror(f)) errno = EIO;
  37  			goto cleanup;
  38  		}
  39  		if (swap) {
  40  			for (i = 0; i < resp[INITGRNGRPS]; i++)
  41  				nscdbuf[i] = bswap_32(nscdbuf[i]);
  42  		}
  43  	}
  44  	fclose(f);
  45  
  46  	f = fopen("/etc/group", "rbe");
  47  	if (!f && errno != ENOENT && errno != ENOTDIR)
  48  		goto cleanup;
  49  
  50  	if (f) {
  51  		while (!(rv = __getgrent_a(f, &gr, &buf, &size, &mem, &nmem, &res)) && res) {
  52  			if (nscdbuf)
  53  				for (i=0; i < resp[INITGRNGRPS]; i++) {
  54  					if (nscdbuf[i] == gr.gr_gid) nscdbuf[i] = gid;
  55  				}
  56  			for (i=0; gr.gr_mem[i] && strcmp(user, gr.gr_mem[i]); i++);
  57  			if (!gr.gr_mem[i]) continue;
  58  			if (++n <= nlim) *groups++ = gr.gr_gid;
  59  		}
  60  		if (rv) {
  61  			errno = rv;
  62  			goto cleanup;
  63  		}
  64  	}
  65  	if (nscdbuf) {
  66  		for(i=0; i < resp[INITGRNGRPS]; i++) {
  67  			if (nscdbuf[i] != gid)
  68  				if(++n <= nlim) *groups++ = nscdbuf[i];
  69  		}
  70  	}
  71  
  72  	ret = n > nlim ? -1 : n;
  73  	*ngroups = n;
  74  
  75  cleanup:
  76  	if (f) fclose(f);
  77  	free(nscdbuf);
  78  	free(buf);
  79  	free(mem);
  80  	return ret;
  81  }
  82