From 9d81146b015e8f4f611357c4cef17fbfb2f4bd54 Mon Sep 17 00:00:00 2001
From: Etienne Dechamps <etienne.dechamps@ovh.net>
Date: Thu, 4 Oct 2012 16:09:12 +0200
Subject: [PATCH] Use dynamic file descriptor numbers in ztest.
Currently, ztest expects to get 3 and 4 as the file descriptors for
data and random files, respectively. This is quite fragile and breaks
easily if ztest is run with these file descriptors already opened
(e.g. in a complex shell script).
This patch fixes the issue by removing the assumptions on the file
descriptor numbers that open() returns.
For the random file (/dev/urandom), the new code doesn't rely on a
shared file descriptor; instead, it reopens the file in the child.
For the data file, the new code writes the file descriptor number into
a "ZTEST_FD_DATA" environment variable so that it can be recovered
after the execv() call.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
---
cmd/ztest/ztest.c | 59 ++++++++++++++++++++++-------------------------
1 file changed, 28 insertions(+), 31 deletions(-)
diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 9da15a1859..973e7b2f6a 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -121,8 +121,8 @@
#include <sys/fs/zfs.h>
#include <libnvpair.h>
-#define ZTEST_FD_DATA 3
-#define ZTEST_FD_RAND 4
+static int ztest_fd_data = -1;
+static int ztest_fd_rand = -1;
typedef struct ztest_shared_hdr {
uint64_t zh_hdr_size;
@@ -783,10 +783,12 @@ ztest_random(uint64_t range)
{
uint64_t r;
+ ASSERT3S(ztest_fd_rand, >=, 0);
+
if (range == 0)
return (0);
- if (read(ZTEST_FD_RAND, &r, sizeof (r)) != sizeof (r))
+ if (read(ztest_fd_rand, &r, sizeof (r)) != sizeof (r))
fatal(1, "short read from /dev/urandom");
return (r % range);
@@ -5815,26 +5817,13 @@ ztest_init(ztest_shared_t *zs)
}
static void
-setup_fds(void)
+setup_data_fd(void)
{
- int fd;
-
char *tmp = tempnam(NULL, NULL);
- fd = open(tmp, O_RDWR | O_CREAT, 0700);
- ASSERT3S(fd, >=, 0);
- if (fd != ZTEST_FD_DATA) {
- VERIFY3S(dup2(fd, ZTEST_FD_DATA), ==, ZTEST_FD_DATA);
- close(fd);
- }
+ ztest_fd_data = open(tmp, O_RDWR | O_CREAT, 0700);
+ ASSERT3S(ztest_fd_data, >=, 0);
(void) unlink(tmp);
free(tmp);
-
- fd = open("/dev/urandom", O_RDONLY);
- ASSERT3S(fd, >=, 0);
- if (fd != ZTEST_FD_RAND) {
- VERIFY3S(dup2(fd, ZTEST_FD_RAND), ==, ZTEST_FD_RAND);
- close(fd);
- }
}
static int
@@ -5858,10 +5847,10 @@ setup_hdr(void)
ztest_shared_hdr_t *hdr;
hdr = (void *)mmap(0, P2ROUNDUP(sizeof (*hdr), getpagesize()),
- PROT_READ | PROT_WRITE, MAP_SHARED, ZTEST_FD_DATA, 0);
+ PROT_READ | PROT_WRITE, MAP_SHARED, ztest_fd_data, 0);
ASSERT(hdr != MAP_FAILED);
- VERIFY3U(0, ==, ftruncate(ZTEST_FD_DATA, sizeof (ztest_shared_hdr_t)));
+ VERIFY3U(0, ==, ftruncate(ztest_fd_data, sizeof (ztest_shared_hdr_t)));
hdr->zh_hdr_size = sizeof (ztest_shared_hdr_t);
hdr->zh_opts_size = sizeof (ztest_shared_opts_t);
@@ -5872,7 +5861,7 @@ setup_hdr(void)
hdr->zh_ds_count = ztest_opts.zo_datasets;
size = shared_data_size(hdr);
- VERIFY3U(0, ==, ftruncate(ZTEST_FD_DATA, size));
+ VERIFY3U(0, ==, ftruncate(ztest_fd_data, size));
(void) munmap((caddr_t)hdr, P2ROUNDUP(sizeof (*hdr), getpagesize()));
}
@@ -5885,14 +5874,14 @@ setup_data(void)
uint8_t *buf;
hdr = (void *)mmap(0, P2ROUNDUP(sizeof (*hdr), getpagesize()),
- PROT_READ, MAP_SHARED, ZTEST_FD_DATA, 0);
+ PROT_READ, MAP_SHARED, ztest_fd_data, 0);
ASSERT(hdr != MAP_FAILED);
size = shared_data_size(hdr);
(void) munmap((caddr_t)hdr, P2ROUNDUP(sizeof (*hdr), getpagesize()));
hdr = ztest_shared_hdr = (void *)mmap(0, P2ROUNDUP(size, getpagesize()),
- PROT_READ | PROT_WRITE, MAP_SHARED, ZTEST_FD_DATA, 0);
+ PROT_READ | PROT_WRITE, MAP_SHARED, ztest_fd_data, 0);
ASSERT(hdr != MAP_FAILED);
buf = (uint8_t *)hdr;
@@ -5925,9 +5914,15 @@ exec_child(char *cmd, char *libpath, boolean_t ignorekill, int *statusp)
if (pid == 0) { /* child */
char *emptyargv[2] = { cmd, NULL };
+ char fd_data_str[12];
struct rlimit rl = { 1024, 1024 };
(void) setrlimit(RLIMIT_NOFILE, &rl);
+
+ (void) close(ztest_fd_rand);
+ VERIFY(11 >= snprintf(fd_data_str, 12, "%d", ztest_fd_data));
+ VERIFY(0 == setenv("ZTEST_FD_DATA", fd_data_str, 1));
+
(void) enable_extended_FILE_stdio(-1, -1);
if (libpath != NULL)
VERIFY(0 == setenv("LD_LIBRARY_PATH", libpath, 1));
@@ -6005,22 +6000,24 @@ main(int argc, char **argv)
char cmd[MAXNAMELEN];
boolean_t hasalt;
int f;
- boolean_t ischild = (0 == lseek(ZTEST_FD_DATA, 0, SEEK_CUR));
-
- ASSERT(ischild || errno == EBADF || errno == ESPIPE);
+ char *fd_data_str = getenv("ZTEST_FD_DATA");
(void) setvbuf(stdout, NULL, _IOLBF, 0);
- if (!ischild) {
+ ztest_fd_rand = open("/dev/urandom", O_RDONLY);
+ ASSERT3S(ztest_fd_rand, >=, 0);
+
+ if (!fd_data_str) {
dprintf_setup(&argc, argv);
process_options(argc, argv);
- setup_fds();
+ setup_data_fd();
setup_hdr();
setup_data();
bcopy(&ztest_opts, ztest_shared_opts,
sizeof (*ztest_shared_opts));
} else {
+ ztest_fd_data = atoi(fd_data_str);
setup_data();
bcopy(ztest_shared_opts, &ztest_opts, sizeof (ztest_opts));
}
@@ -6029,12 +6026,12 @@ main(int argc, char **argv)
/* Override location of zpool.cache */
(void) asprintf((char **)&spa_config_path, "%s/zpool.cache",
ztest_opts.zo_dir);
-
+
ztest_ds = umem_alloc(ztest_opts.zo_datasets * sizeof (ztest_ds_t),
UMEM_NOFAIL);
zs = ztest_shared;
- if (ischild) {
+ if (fd_data_str) {
metaslab_gang_bang = ztest_opts.zo_metaslab_gang_bang;
metaslab_df_alloc_threshold =
zs->zs_metaslab_df_alloc_threshold;