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#include <stdio.h>
#include <limits.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <grp.h>
#include <pwd.h>
#include <pwdb/pwdb_public.h>
/*
* prototype to shut off compiler warnings
*/
void pgroup(gid_t gid);
void puser(uid_t uid);
void pallg(void);
/* grp numbers in decimal with name */
void pgroup(gid_t gid)
{
struct group *grp;
grp = getgrgid(gid);
if (grp == NULL) {
fprintf(stderr, "gid(%ld) is an unknown group\n", (long int) gid);
} else {
printf("gid(%ld) = %s\nmembers:\n"
, (long int) grp->gr_gid, grp->gr_name);
while (grp->gr_mem && *grp->gr_mem) {
printf("\t%s\n", *grp->gr_mem);
(grp->gr_mem)++;
}
}
}
/* uid in decimal with name */
void puser(uid_t uid)
{
struct passwd *pwd;
pwd = getpwuid(uid);
if (pwd == NULL) {
fprintf(stderr, "uid(%ld) is not known\n", (long int) uid);
} else {
printf("uid(%ld) = %s runs %s from %s\n"
, (long int) pwd->pw_uid, pwd->pw_name
, pwd->pw_shell, pwd->pw_dir);
pgroup(pwd->pw_gid);
}
}
/* list all groups */
void pallg(void)
{
int ngs, i;
gid_t *gids=NULL;
ngs = getgroups(0, NULL);
gids = calloc(ngs, sizeof(*gids));
ngs = getgroups(ngs, gids);
printf("Supplementary groups:\n");
for (i=0; i<ngs; ++i) {
pgroup(gids[i]);
}
printf("---------\n");
free(gids);
}
void main(void)
{
const char *user;
struct passwd *pwd;
/* identify user invoking this program */
/* - logname */
user = getlogin();
pwd = getpwnam(user);
if (pwd == NULL) {
fprintf(stderr, "cannot identify log-name user %s\n", user);
} else {
printf("log-name = %s >\n", user);
puser(pwd->pw_uid);
printf("--\n");
}
/* - current user */
printf("Invoking user >\n");
puser(getuid());
/* - (e)uid and (e)user */
printf("Effective user >\n");
puser(geteuid());
exit(0);
}
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