curl/tests/libtest/lib537.c

/*****************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * $Id$
 */

#include "test.h"

#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_RESOURCE_H
#include <sys/resource.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif

#define SAFETY_MARGIN (10)

#if defined(WIN32) || defined(_WIN32) || defined(MSDOS)
#define DEV_NULL "NUL"
#else
#define DEV_NULL "/dev/null"
#endif

#if defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT)

static int *fd = NULL;
static struct rlimit num_open;
static char msgbuff[256];

/*
 * our_errno() returns the NOT *socket-related* errno (or equivalent)
 * on this platform to hide platform specific for the calling function.
 */

static int our_errno(void)
{
#ifdef WIN32
  return (int)GetLastError();
#else
  return errno;
#endif
}

static void store_errmsg(const char *msg, int err)
{
  if (!err)
    sprintf(msgbuff, "%s", msg);
  else
    sprintf(msgbuff, "%s, errno %d, %s", msg, err, strerror(err));
}

static void close_file_descriptors(void)
{
  for (num_open.rlim_cur = 0;
       num_open.rlim_cur < num_open.rlim_max;
       num_open.rlim_cur++)
    if (fd[num_open.rlim_cur] > 0)
      close(fd[num_open.rlim_cur]);
  free(fd);
  fd = NULL;
}

static int rlimit(int keep_open)
{
  int *tmpfd;
  int nitems, i;
  int *memchunk = NULL;
  char *fmt;
  struct rlimit rl;
  char strbuff[256];
  char strbuff1[81];
  char fmt_u[] = "%u";
  char fmt_lu[] = "%lu";
#ifdef HAVE_LONGLONG
  char fmt_llu[] = "%llu";

  if (sizeof(rl.rlim_max) > sizeof(long))
    fmt = fmt_llu;
  else
#endif
    fmt = (sizeof(rl.rlim_max) < sizeof(long))?fmt_u:fmt_lu;

  /* get initial open file limits */

  if (getrlimit(RLIMIT_NOFILE, &rl) != 0) {
    store_errmsg("getrlimit() failed", our_errno());
    fprintf(stderr, "%s\n", msgbuff);
    return -1;
  }

  /* show initial open file limits */

#ifdef RLIM_INFINITY
  if (rl.rlim_cur == RLIM_INFINITY)
    strcpy(strbuff, "INFINITY");
  else
#endif
    sprintf(strbuff, fmt, rl.rlim_cur);
  fprintf(stderr, "initial soft limit: %s\n", strbuff);

#ifdef RLIM_INFINITY
  if (rl.rlim_max == RLIM_INFINITY)
    strcpy(strbuff, "INFINITY");
  else
#endif
    sprintf(strbuff, fmt, rl.rlim_max);
  fprintf(stderr, "initial hard limit: %s\n", strbuff);

  /*
   * if soft limit and hard limit are different we ask the
   * system to raise soft limit all the way up to the hard
   * limit. Due to some other system limit the soft limit
   * might not be raised up to the hard limit. So from this
   * point the resulting soft limit is our limit. Trying to
   * open more than soft limit file descriptors will fail.
   */

  if (rl.rlim_cur != rl.rlim_max) {

    fprintf(stderr, "raising soft limit up to hard limit\n");
    rl.rlim_cur = rl.rlim_max;
    if (setrlimit(RLIMIT_NOFILE, &rl) != 0) {
      store_errmsg("setrlimit() failed", our_errno());
      fprintf(stderr, "%s\n", msgbuff);
      return -2;
    }

    /* get current open file limits */

    if (getrlimit(RLIMIT_NOFILE, &rl) != 0) {
      store_errmsg("getrlimit() failed", our_errno());
      fprintf(stderr, "%s\n", msgbuff);
      return -3;
    }

    /* show current open file limits */

#ifdef RLIM_INFINITY
    if (rl.rlim_cur == RLIM_INFINITY)
      strcpy(strbuff, "INFINITY");
    else
#endif
      sprintf(strbuff, fmt, rl.rlim_cur);
    fprintf(stderr, "current soft limit: %s\n", strbuff);

#ifdef RLIM_INFINITY
    if (rl.rlim_max == RLIM_INFINITY)
      strcpy(strbuff, "INFINITY");
    else
#endif
      sprintf(strbuff, fmt, rl.rlim_max);
    fprintf(stderr, "current hard limit: %s\n", strbuff);

  } /* (rl.rlim_cur != rl.rlim_max) */

  /*
   * test 537 is all about testing libcurl functionality
   * when the system has nearly exhausted the number of
   * available file descriptors. Test 537 will try to run 
   * with a very small number of file descriptors available.
   * This implies that any file descriptor which is open
   * when the test runs will have a number in the high range
   * of whatever the system supports.
   */

  /*
   * reserve a chunk of memory before opening file descriptors to
   * avoid a low memory condition once the file descriptors are
   * open. System conditions that could make the test fail should
   * be addressed in the precheck phase. This chunk of memory shall
   * be always free()ed before exiting the rlimit() function so
   * that it becomes available to the test.
   */

  nitems = INT_MAX / sizeof(*memchunk);
  do {
    memchunk = malloc(sizeof(*memchunk) * (size_t)nitems);
    if (!memchunk)
      nitems /= 2;
  } while (nitems && !memchunk);
  if (!memchunk) {
    store_errmsg("memchunk, malloc() failed", our_errno());
    fprintf(stderr, "%s\n", msgbuff);
    return -4;
  }

  /* initialize it to fight lazy allocation */

  for (i = 0; i < nitems; i++)
    memchunk[i] = -1;

  /* set the number of file descriptors we will try to open */

#ifdef RLIM_INFINITY
  if ((rl.rlim_cur > 0) && (rl.rlim_cur != RLIM_INFINITY)) {
#else
  if (rl.rlim_cur > 0) {
#endif
    /* soft limit minus SAFETY_MARGIN */
    num_open.rlim_max = rl.rlim_cur - SAFETY_MARGIN;
  }
  else {
    /* a huge number of file descriptors */
    num_open.rlim_max = INT_MAX / sizeof(*fd);
  }

  /* verify that we won't overflow size_t in malloc() */

  if (num_open.rlim_max > ((size_t)-1) / sizeof(*fd)) {
    sprintf(strbuff1, fmt, num_open.rlim_max);
    sprintf(strbuff, "unable to allocate an array for %s "
            "file descriptors, would overflow size_t", strbuff1);
    store_errmsg(strbuff, 0);
    fprintf(stderr, "%s\n", msgbuff);
    free(memchunk);
    return -5;
  }

  /* allocate array for file descriptors */

  do {
    sprintf(strbuff, fmt, num_open.rlim_max);
    fprintf(stderr, "allocating array for %s file descriptors\n", strbuff);
    fd = malloc(sizeof(*fd) * (size_t)(num_open.rlim_max));
    if (!fd) {
      fprintf(stderr, "fd, malloc() failed\n");
      num_open.rlim_max /= 2;
    }
  } while (num_open.rlim_max && !fd);
  if (!fd) {
    store_errmsg("fd, malloc() failed", our_errno());
    fprintf(stderr, "%s\n", msgbuff);
    free(memchunk);
    return -6;
  }

  /* initialize it to fight lazy allocation */

  for (num_open.rlim_cur = 0;
       num_open.rlim_cur < num_open.rlim_max;
       num_open.rlim_cur++)
    fd[num_open.rlim_cur] = -1;

  sprintf(strbuff, fmt, num_open.rlim_max);
  fprintf(stderr, "trying to open %s file descriptors\n", strbuff);

  /* open a dummy descriptor */

  fd[0] = open(DEV_NULL, O_RDONLY);
  if (fd[0] < 0) {
    sprintf(strbuff, "opening of %s failed", DEV_NULL);
    store_errmsg(strbuff, our_errno());
    fprintf(stderr, "%s\n", msgbuff);
    free(fd);
    fd = NULL;
    free(memchunk);
    return -7;
  }

  /* create a bunch of file descriptors */

  for (num_open.rlim_cur = 1; 
       num_open.rlim_cur < num_open.rlim_max; 
       num_open.rlim_cur++) {

    fd[num_open.rlim_cur] = dup(fd[0]);

    if (fd[num_open.rlim_cur] < 0) {

      fd[num_open.rlim_cur] = -1;

      sprintf(strbuff1, fmt, num_open.rlim_cur);
      sprintf(strbuff, "dup() attempt %s failed", strbuff1);
      fprintf(stderr, "%s\n", strbuff);

      sprintf(strbuff1, fmt, num_open.rlim_cur);
      sprintf(strbuff, "fd system limit seems close to %s", strbuff1);
      fprintf(stderr, "%s\n", strbuff);

      num_open.rlim_max = num_open.rlim_cur - SAFETY_MARGIN;

      num_open.rlim_cur -= num_open.rlim_max;
      sprintf(strbuff1, fmt, num_open.rlim_cur);
      sprintf(strbuff, "closing %s file descriptors", strbuff1);
      fprintf(stderr, "%s\n", strbuff);

      for (num_open.rlim_cur = num_open.rlim_max;
           fd[num_open.rlim_cur] >= 0;
           num_open.rlim_cur++) {
        close(fd[num_open.rlim_cur]);
        fd[num_open.rlim_cur] = -1;
      }

      sprintf(strbuff, fmt, num_open.rlim_max);
      fprintf(stderr, "shrinking array for %s file descriptors\n", strbuff);

      /* we don't care if we can't shrink it */

      tmpfd = realloc(fd, sizeof(*fd) * (size_t)(num_open.rlim_max));
      if (tmpfd) {
        fd = tmpfd;
        tmpfd = NULL;
      }

      break;

    }

  }

  sprintf(strbuff, fmt, num_open.rlim_max);
  fprintf(stderr, "%s file descriptors open\n", strbuff);

  /* free the chunk of memory we were reserving so that it
     becomes becomes available to the test */

  free(memchunk);

  /* close file descriptors unless instructed to keep them */

  if (!keep_open) {
    close_file_descriptors();
  }

  return 0;
}

int test(char *URL)
{
  CURLcode res;
  CURL *curl;

  if(!strcmp(URL, "check")) {
    /* used by the test script to ask if we can run this test or not */
    if(rlimit(FALSE)) {
      fprintf(stdout, "rlimit problem: %s\n", msgbuff);
      return 1;
    }
    return 0; /* sure, run this! */
  }

  if (rlimit(TRUE)) {
    /* failure */
    return TEST_ERR_MAJOR_BAD;
  }

  /* run the test with the bunch of open file descriptors 
     and close them all once the test is over */

  if (curl_global_init(CURL_GLOBAL_ALL) != CURLE_OK) {
    fprintf(stderr, "curl_global_init() failed\n");
    close_file_descriptors();
    return TEST_ERR_MAJOR_BAD;
  }

  if ((curl = curl_easy_init()) == NULL) {
    fprintf(stderr, "curl_easy_init() failed\n");
    close_file_descriptors();
    curl_global_cleanup();
    return TEST_ERR_MAJOR_BAD;
  }

  curl_easy_setopt(curl, CURLOPT_URL, URL);
  curl_easy_setopt(curl, CURLOPT_HEADER, TRUE);

  res = curl_easy_perform(curl);

  close_file_descriptors();
  curl_easy_cleanup(curl);
  curl_global_cleanup();

  return (int)res;
}

#else /* defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT) */

int test(char *URL)
{
  (void)URL;
  printf("system lacks necessary system function(s)");
  return 1; /* skip test */
}

#endif /* defined(HAVE_GETRLIMIT) && defined(HAVE_SETRLIMIT) */