kaguya
56 lines
1.1 KiB
C
56 lines
1.1 KiB
C
#include <assert.h>
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#include <errno.h>
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#include <grp.h>
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#include <pwd.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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int main() {
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int ngroups = 100;
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struct passwd *pw;
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struct group *gr;
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gid_t *groups;
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bool gid_checked = false;
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int e = 0;
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groups = malloc(sizeof(*groups) * ngroups);
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if(groups == NULL) {
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perror("malloc");
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exit(EXIT_FAILURE);
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}
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/* Fetch passwd structure */
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pw = getpwuid(geteuid());
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if(pw == NULL) {
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perror("getpwnam");
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exit(EXIT_FAILURE);
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}
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/* Retrieve group list */
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e = getgrouplist(pw->pw_name, pw->pw_gid, groups, &ngroups);
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assert(e > 0);
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if(e == -1) {
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fprintf(stderr, "getgrouplist() returned -1 (%s); ngroups = %d\n", strerror(errno), ngroups);
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exit(EXIT_FAILURE);
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}
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/* Display list of retrieved groups, along with group names */
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fprintf(stderr, "ngroups = %d\n", ngroups);
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for(int j = 0; j < ngroups; j++) {
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if(groups[j] == pw->pw_gid)
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gid_checked = true;
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printf("%d", groups[j]);
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gr = getgrgid(groups[j]);
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if(gr != NULL)
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printf(" (%s)", gr->gr_name);
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printf("\n");
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}
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assert(gid_checked);
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exit(EXIT_SUCCESS);
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}
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