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#include "env_info.h" #include <pwd.h>     // for getpwuid_r, passwd#include <stdlib.h>  // for rand, free, mblen, size_t, exit#include <string.h>#include <unistd.h>  // for gethostname, getuid, read, sysconf #include "logging.h"#include "mlock_page.h"#include "util.h" int GetHostName(char* hostname_buf, size_t hostname_buflen) {  if (gethostname(hostname_buf, hostname_buflen)) {    LogErrno("gethostname");    return 0;  }  hostname_buf[hostname_buflen - 1] = 0;  return 1;} int GetUserName(char* username_buf, size_t username_buflen) {  struct passwd* pwd = NULL;  struct passwd pwd_storage;  char* pwd_buf;  long pwd_bufsize = sysconf(_SC_GETPW_R_SIZE_MAX);  if (pwd_bufsize < 0) {    pwd_bufsize = 1 << 20;  }  pwd_buf = malloc((size_t)pwd_bufsize);  if (!pwd_buf) {    LogErrno("malloc(pwd_bufsize)");    return 0;  }  if (MLOCK_PAGE(pwd_buf, pwd_bufsize) < 0) {    // We continue anyway, as very likely getpwuid_r won't retrieve a password    // hash on modern systems.    LogErrno("mlock");  }  getpwuid_r(getuid(), &pwd_storage, pwd_buf, (size_t)pwd_bufsize, &pwd);  if (!pwd) {    LogErrno("getpwuid_r");    free(pwd_buf);    return 0;  }  if (strlen(pwd->pw_name) >= username_buflen) {    Log("Username too long: got %d, want < %d", (int)strlen(pwd->pw_name),        (int)username_buflen);    free(pwd_buf);    return 0;  }  strncpy(username_buf, pwd->pw_name, username_buflen);  username_buf[username_buflen - 1] = 0;  explicit_bzero(pwd_buf, pwd_bufsize);  free(pwd_buf);  return 1;}