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#include <stdlib.h>
#include <stdio.h>
#include <grp.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <stdbool.h>
void check_root_group(struct group *grp) {
assert(grp);
printf("group name: %s\n", grp->gr_name);
fflush(stdout);
assert(grp->gr_gid == 0);
assert(!strcmp(grp->gr_name, "root"));
// Depending on your system, the root group may or may not contain the root user.
if (grp->gr_mem[0] != NULL) {
bool found = false;
for (size_t i = 0; grp->gr_mem[i] != NULL; i++) {
printf("group member: %s\n", grp->gr_mem[i]);
fflush(stdout);
if (!strcmp(grp->gr_mem[i], "root")) {
found = true;
break;
}
}
assert(found);
}
}
int main()
{
struct group grp, *result = NULL;
char *buf;
size_t bufsize;
int s;
bool password = false;
bufsize = sysconf(_SC_GETGR_R_SIZE_MAX);
assert(bufsize > 0 && bufsize < 0x100000);
buf = malloc(bufsize);
assert(buf);
s = getgrnam_r("root", &grp, buf, bufsize, &result);
assert(!s);
check_root_group(result);
s = getgrgid_r(0, &grp, buf, bufsize, &result);
assert(!s);
check_root_group(result);
result = getgrnam("root");
check_root_group(result);
result = getgrgid(0);
check_root_group(result);
result = getgrnam("this_group_doesnt_exist");
assert(!result);
#ifndef USE_HOST_LIBC
// This is not guaranteed.
assert(errno == ESRCH);
#endif
s = getgrnam_r("this_group_doesnt_exist", &grp, buf, bufsize, &result);
assert(!result);
#ifndef USE_HOST_LIBC
// This is not guaranteed.
assert(s == ESRCH);
#endif
errno = 0;
setgrent();
assert(errno == 0);
result = getgrent();
assert(result);
grp.gr_name = strdup(result->gr_name);
if(result->gr_passwd) {
password = true;
}
grp.gr_passwd = strdup(result->gr_passwd);
grp.gr_gid = result->gr_gid;
assert(grp.gr_name);
if(password)
assert(grp.gr_passwd);
assert(grp.gr_name);
if(password)
assert(grp.gr_passwd);
endgrent();
result = getgrent();
assert(result);
assert(strcmp(result->gr_name, grp.gr_name) == 0);
if(password)
assert(strcmp(result->gr_passwd, grp.gr_passwd) == 0);
assert(result->gr_gid == grp.gr_gid);
free(grp.gr_name);
if(password)
free(grp.gr_passwd);
free(buf);
}
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