lazysphere/command/id.c

#include "args.h"
#include "command.h"
#include "lslib.h"

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

static void help (void) {
    printf("Usage: id [USER]\n\n");
    printf("Print information about the USER\n");
}

COMMAND(user_id) {
    
    uid_t uid;
    gid_t gid, *groups;
    int ngroups, i;
    struct passwd* pw;
    struct group* ugr;

    parse_help(argc, argv, help);
    
    if (argc < 1) {
        uid = getuid();
        pw = getpwuid(uid);
    } else {
        pw = getpwnam(argv[0]);
    }

    if(pw == NULL){
        if (errno == 0) {
            error("user not found");
        } else {
            error("failed to fetch groups: %s", strerror(errno));
        }
    }

    uid = pw->pw_uid;
    
    ngroups = 0;
    getgrouplist(pw->pw_name, pw->pw_gid, NULL, &ngroups);
    
    groups = malloc(sizeof(gid_t) * ngroups);
    getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
   
    gid = pw->pw_gid;
    ugr = getgrgid(gid);
    printf("uid=%d(%s) gid=%d(%s) ",
           uid, ugr->gr_name, gid, ugr->gr_name);
    
    if (ngroups > 0) {
        printf("groups=");
    }

    for (i = 0; i < ngroups; i++){
        struct group* gr = getgrgid(groups[i]);
        if(gr == NULL) {
            free(groups);
            error("failed to fetch groups: %s", strerror(errno));
        }
        
        printf("%d(%s)", gr->gr_gid, gr->gr_name);
        
        if (i + 1 < ngroups) putchar(',');
    }

    printf("\b\n");

    free(groups);

    return EXIT_SUCCESS;
}