[Bug nss/26760] New: getaddrinfo_a blocks in a forked process after it was finished in the parent process

[Bug nss/26760] New: getaddrinfo_a blocks in a forked process after it was finished in the parent process

[nobu@ruby-lang.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26760

            Bug ID: 26760
           Summary: getaddrinfo_a blocks in a forked process after it was
                    finished in the parent process
           Product: glibc
           Version: 2.31
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: nss
          Assignee: unassigned at sourceware dot org
          Reporter: nobu@ruby-lang.org
  Target Milestone: ---

getaddrinfo_a hangs up when called in a process forked within 1 second after it
finished in the parent process.

// gaitest.c
#define _GNU_SOURCE
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/wait.h>

int
test_gai(const char *where, const char *name)
{
  printf("in %s: ", where);
  fflush(stdout);
  struct gaicb req = {.ar_name = name};
  struct gaicb *reqs[1] = {&req};
  int ret = getaddrinfo_a(GAI_NOWAIT, reqs, 1, NULL);
  if (ret) goto error;
  ret = gai_suspend((const struct gaicb **)reqs, 1, NULL);
  if (ret) goto error;
  ret = gai_error(reqs[0]);
  if (ret) goto error;
  struct addrinfo *ai = reqs[0]->ar_result;
  if (ai) {
    printf("%s\n", ai->ai_canonname ? ai->ai_canonname : "noname");
  }
  return 0;
 error:
  fprintf(stderr, "failed: %s\n", gai_strerror(ret));
  return ret;
}

int
main(int argc, char **argv)
{
  test_gai("parent", "localhost");
  if (argc > 1) {
    printf("sleeping...");
    fflush(stdout);
    usleep((useconds_t)(atof(argv[1])*1e6));
    printf("\n");
  }
  pid_t pid = fork();
  if (pid == 0) {
    test_gai("child", "localhost");
    return 0;
  }
  int status;
  waitpid(pid, &status, 0);
  return status;
}
// end of gaitest.c

$ gcc -o gaitest gaitest.c -lanl

$ ./gaitest 1
in parent: noname
sleeping...
in child: noname

$ ./gaitest 0.9
in parent: noname
sleeping...
in child: ^C

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[Bug nss/26760] getaddrinfo_a blocks in a forked process after it was finished in the parent process

[schwab@linux-m68k.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=26760

--- Comment #1 from Andreas Schwab <schwab@linux-m68k.org> ---
I don't think getaddrinfo_a is intented to be async-signal-safe.

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[Bug nss/26760] getaddrinfo_a blocks in a forked process after it was finished in the parent process

[yasuo.honda at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26760

Yasuo Honda <yasuo.honda at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |yasuo.honda at gmail dot com

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