greenplumn pg_mkdir_p_test 源码
greenplumn pg_mkdir_p_test 代码
文件路径:/src/backend/utils/misc/test/pg_mkdir_p_test.c
/*
* Validate a race condition issue in pg_mkdir_p().
*
* pg_mkdir_p() is used by tablespace, initdb and pg_basebackup to create a
* directory as well as its parent directories. The logic used to be like
* below:
*
* if (stat(path) < 0)
* {
* if (mkdir(path) < 0)
* retval = -1;
* }
*
* It first checks for the existence of the path, if path does not pre-exist
* then it creates the directory. However if two processes try to create path
* concurrently, then one possible execution order is as below:
*
* A: stat(path) returns -1, so decide to create it;
* B: stat(path) returns -1, so decide to create it;
* B: mkdir(path) returns 0, successfully created path;
* A: mkdir(path) returns -1, fail to create path as it already exist;
*
* It could be triggered easily with initdb:
*
* testdir=/tmp/testdir
* datadir=$testdir/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z
*
* rm -rf $testdir
* mkdir $testdir
*
* # init two databases with common parent directories
* initdb -D $datadir/db1 >$testdir/db1.log 2>&1 &
* initdb -D $datadir/db2 >$testdir/db2.log 2>&1 &
*
* # wait for them to finish and check for the error
* wait
* cd $testdir
* grep 'could not create directory' *.log
*
* The fail rate is not 100% but should be large enough to happen in 5 tries.
*
* This race condition could be fixed by swapping the order of stat() and
* mkdir(), this is also what the "mkdir -p" command does.
*
* In this test module we test concurrent calls to pg_mkdir_p() to ensure the
* race condition does not happen.
*/
#include <errno.h>
#include <pthread.h>
#include <sys/stat.h>
#include <stdarg.h>
#include <stddef.h>
#include <setjmp.h>
#include "cmockery.h"
#include "postgres.h"
#include "port.h"
#include "utils/memutils.h"
#define TESTDIR "/tmp/testdir_pg_mkdir_p"
#define DATADIR TESTDIR "/a/b/c/d/e/f/g/h/i/j/k/l/m/n/o/p/q/r/s/t/u/v/w/x/y/z"
/*
* A struct to pass arguments to the thread and return the results.
*/
typedef struct
{
pthread_t tid; /* thread id */
char path[MAXPGPATH]; /* the path to create */
int retcode; /* return code of pg_mkdir_p() */
int error; /* errno */
} Job;
static void *
job_thread(void *arg)
{
Job *job = (Job *) arg;
errno = 0;
job->retcode = pg_mkdir_p(job->path, S_IRWXU);
job->error = errno;
return NULL;
}
/*
* This function accepts in integer argument n, it will launch n concurrent
* threads to call pg_mkdir_p() to create the same dir and check for errors
* from them.
*/
static void
concurrent_pg_mkdir_p(int n)
{
Job *jobs = malloc(sizeof(Job) * n);
int failed = 0;
int i;
/* Create concurrent threads to execute pg_mkdir_p() */
for (i = 0; i < n; i++)
{
Job *job = &jobs[i];
strncpy(job->path, DATADIR, sizeof(job->path));
pthread_create(&job->tid, NULL, job_thread, job);
}
/* Check for the results */
for (i = 0; i < n; i++)
{
Job *job = &jobs[i];
pthread_join(job->tid, NULL);
if (job->retcode < 0)
{
/*
* Only show the message, do not error out until we joined all
* the threads.
*/
print_error("job %d: could not create directory \"%s\": %s\n",
i, job->path, strerror(job->error));
failed++;
}
}
assert_int_equal(failed, 0);
free(jobs);
}
static void
test__pgmkdirp__1(void **state)
{
concurrent_pg_mkdir_p(1);
}
static void
test__pgmkdirp__2(void **state)
{
concurrent_pg_mkdir_p(2);
}
static void
test__pgmkdirp__4(void **state)
{
concurrent_pg_mkdir_p(4);
}
static void
test__pgmkdirp__8(void **state)
{
concurrent_pg_mkdir_p(8);
}
static void
test__pgmkdirp__16(void **state)
{
concurrent_pg_mkdir_p(16);
}
static void
test__pgmkdirp__32(void **state)
{
concurrent_pg_mkdir_p(32);
}
static void
setup(void **state)
{
/* if the dir does not exist rmtree() would raise a warning, suppress it */
mkdir(TESTDIR, S_IRWXU);
rmtree(TESTDIR, true);
}
static void
teardown(void **state)
{
rmtree(TESTDIR, true);
}
int
main(int argc, char* argv[])
{
cmockery_parse_arguments(argc, argv);
const UnitTest tests[] = {
unit_test_setup_teardown(test__pgmkdirp__1, setup, teardown),
unit_test_setup_teardown(test__pgmkdirp__2, setup, teardown),
unit_test_setup_teardown(test__pgmkdirp__4, setup, teardown),
unit_test_setup_teardown(test__pgmkdirp__8, setup, teardown),
unit_test_setup_teardown(test__pgmkdirp__16, setup, teardown),
unit_test_setup_teardown(test__pgmkdirp__32, setup, teardown),
};
MemoryContextInit();
return run_tests(tests);
}
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