qemu/qemu-io.c
Chrysostomos Nanakos 2f78e491d7 async: aio_context_new(): Handle event_notifier_init failure
On a system with a low limit of open files the initialization
of the event notifier could fail and QEMU exits without printing any
error information to the user.

The problem can be easily reproduced by enforcing a low limit of open
files and start QEMU with enough I/O threads to hit this limit.

The same problem raises, without the creation of I/O threads, while
QEMU initializes the main event loop by enforcing an even lower limit of
open files.

This commit adds an error message on failure:

 # qemu [...] -object iothread,id=iothread0 -object iothread,id=iothread1
 qemu: Failed to initialize event notifier: Too many open files in system

Signed-off-by: Chrysostomos Nanakos <cnanakos@grnet.gr>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:39:48 +01:00

490 lines
12 KiB
C

/*
* Command line utility to exercise the QEMU I/O path.
*
* Copyright (C) 2009 Red Hat, Inc.
* Copyright (c) 2003-2005 Silicon Graphics, Inc.
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include <sys/time.h>
#include <sys/types.h>
#include <stdarg.h>
#include <stdio.h>
#include <getopt.h>
#include <libgen.h>
#include "qemu-io.h"
#include "qemu/main-loop.h"
#include "qemu/option.h"
#include "qemu/config-file.h"
#include "qemu/readline.h"
#include "block/block_int.h"
#include "trace/control.h"
#define CMD_NOFILE_OK 0x01
static char *progname;
static BlockDriverState *qemuio_bs;
/* qemu-io commands passed using -c */
static int ncmdline;
static char **cmdline;
static ReadLineState *readline_state;
static int close_f(BlockDriverState *bs, int argc, char **argv)
{
bdrv_unref(bs);
qemuio_bs = NULL;
return 0;
}
static const cmdinfo_t close_cmd = {
.name = "close",
.altname = "c",
.cfunc = close_f,
.oneline = "close the current open file",
};
static int openfile(char *name, int flags, int growable, QDict *opts)
{
Error *local_err = NULL;
if (qemuio_bs) {
fprintf(stderr, "file open already, try 'help close'\n");
QDECREF(opts);
return 1;
}
qemuio_bs = bdrv_new("hda", &error_abort);
if (growable) {
flags |= BDRV_O_PROTOCOL;
}
if (bdrv_open(&qemuio_bs, name, NULL, opts, flags, NULL, &local_err) < 0) {
fprintf(stderr, "%s: can't open%s%s: %s\n", progname,
name ? " device " : "", name ?: "",
error_get_pretty(local_err));
error_free(local_err);
bdrv_unref(qemuio_bs);
qemuio_bs = NULL;
return 1;
}
return 0;
}
static void open_help(void)
{
printf(
"\n"
" opens a new file in the requested mode\n"
"\n"
" Example:\n"
" 'open -Cn /tmp/data' - creates/opens data file read-write and uncached\n"
"\n"
" Opens a file for subsequent use by all of the other qemu-io commands.\n"
" -r, -- open file read-only\n"
" -s, -- use snapshot file\n"
" -n, -- disable host cache\n"
" -g, -- allow file to grow (only applies to protocols)\n"
" -o, -- options to be given to the block driver"
"\n");
}
static int open_f(BlockDriverState *bs, int argc, char **argv);
static const cmdinfo_t open_cmd = {
.name = "open",
.altname = "o",
.cfunc = open_f,
.argmin = 1,
.argmax = -1,
.flags = CMD_NOFILE_OK,
.args = "[-Crsn] [-o options] [path]",
.oneline = "open the file specified by path",
.help = open_help,
};
static QemuOptsList empty_opts = {
.name = "drive",
.merge_lists = true,
.head = QTAILQ_HEAD_INITIALIZER(empty_opts.head),
.desc = {
/* no elements => accept any params */
{ /* end of list */ }
},
};
static int open_f(BlockDriverState *bs, int argc, char **argv)
{
int flags = 0;
int readonly = 0;
int growable = 0;
int c;
QemuOpts *qopts;
QDict *opts;
while ((c = getopt(argc, argv, "snrgo:")) != EOF) {
switch (c) {
case 's':
flags |= BDRV_O_SNAPSHOT;
break;
case 'n':
flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
break;
case 'r':
readonly = 1;
break;
case 'g':
growable = 1;
break;
case 'o':
if (!qemu_opts_parse(&empty_opts, optarg, 0)) {
printf("could not parse option list -- %s\n", optarg);
qemu_opts_reset(&empty_opts);
return 0;
}
break;
default:
qemu_opts_reset(&empty_opts);
return qemuio_command_usage(&open_cmd);
}
}
if (!readonly) {
flags |= BDRV_O_RDWR;
}
qopts = qemu_opts_find(&empty_opts, NULL);
opts = qopts ? qemu_opts_to_qdict(qopts, NULL) : NULL;
qemu_opts_reset(&empty_opts);
if (optind == argc - 1) {
return openfile(argv[optind], flags, growable, opts);
} else if (optind == argc) {
return openfile(NULL, flags, growable, opts);
} else {
QDECREF(opts);
return qemuio_command_usage(&open_cmd);
}
}
static int quit_f(BlockDriverState *bs, int argc, char **argv)
{
return 1;
}
static const cmdinfo_t quit_cmd = {
.name = "quit",
.altname = "q",
.cfunc = quit_f,
.argmin = -1,
.argmax = -1,
.flags = CMD_FLAG_GLOBAL,
.oneline = "exit the program",
};
static void usage(const char *name)
{
printf(
"Usage: %s [-h] [-V] [-rsnm] [-c STRING] ... [file]\n"
"QEMU Disk exerciser\n"
"\n"
" -c, --cmd STRING execute command with its arguments\n"
" from the given string\n"
" -r, --read-only export read-only\n"
" -s, --snapshot use snapshot file\n"
" -n, --nocache disable host cache\n"
" -g, --growable allow file to grow (only applies to protocols)\n"
" -m, --misalign misalign allocations for O_DIRECT\n"
" -k, --native-aio use kernel AIO implementation (on Linux only)\n"
" -t, --cache=MODE use the given cache mode for the image\n"
" -T, --trace FILE enable trace events listed in the given file\n"
" -h, --help display this help and exit\n"
" -V, --version output version information and exit\n"
"\n"
"See '%s -c help' for information on available commands."
"\n",
name, name);
}
static char *get_prompt(void)
{
static char prompt[FILENAME_MAX + 2 /*"> "*/ + 1 /*"\0"*/ ];
if (!prompt[0]) {
snprintf(prompt, sizeof(prompt), "%s> ", progname);
}
return prompt;
}
static void GCC_FMT_ATTR(2, 3) readline_printf_func(void *opaque,
const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
vprintf(fmt, ap);
va_end(ap);
}
static void readline_flush_func(void *opaque)
{
fflush(stdout);
}
static void readline_func(void *opaque, const char *str, void *readline_opaque)
{
char **line = readline_opaque;
*line = g_strdup(str);
}
static void completion_match(const char *cmd, void *opaque)
{
readline_add_completion(readline_state, cmd);
}
static void readline_completion_func(void *opaque, const char *str)
{
readline_set_completion_index(readline_state, strlen(str));
qemuio_complete_command(str, completion_match, NULL);
}
static char *fetchline_readline(void)
{
char *line = NULL;
readline_start(readline_state, get_prompt(), 0, readline_func, &line);
while (!line) {
int ch = getchar();
if (ch == EOF) {
break;
}
readline_handle_byte(readline_state, ch);
}
return line;
}
#define MAXREADLINESZ 1024
static char *fetchline_fgets(void)
{
char *p, *line = g_malloc(MAXREADLINESZ);
if (!fgets(line, MAXREADLINESZ, stdin)) {
g_free(line);
return NULL;
}
p = line + strlen(line);
if (p != line && p[-1] == '\n') {
p[-1] = '\0';
}
return line;
}
static char *fetchline(void)
{
if (readline_state) {
return fetchline_readline();
} else {
return fetchline_fgets();
}
}
static void prep_fetchline(void *opaque)
{
int *fetchable = opaque;
qemu_set_fd_handler(STDIN_FILENO, NULL, NULL, NULL);
*fetchable= 1;
}
static void command_loop(void)
{
int i, done = 0, fetchable = 0, prompted = 0;
char *input;
for (i = 0; !done && i < ncmdline; i++) {
done = qemuio_command(qemuio_bs, cmdline[i]);
}
if (cmdline) {
g_free(cmdline);
return;
}
while (!done) {
if (!prompted) {
printf("%s", get_prompt());
fflush(stdout);
qemu_set_fd_handler(STDIN_FILENO, prep_fetchline, NULL, &fetchable);
prompted = 1;
}
main_loop_wait(false);
if (!fetchable) {
continue;
}
input = fetchline();
if (input == NULL) {
break;
}
done = qemuio_command(qemuio_bs, input);
g_free(input);
prompted = 0;
fetchable = 0;
}
qemu_set_fd_handler(STDIN_FILENO, NULL, NULL, NULL);
}
static void add_user_command(char *optarg)
{
cmdline = g_renew(char *, cmdline, ++ncmdline);
cmdline[ncmdline-1] = optarg;
}
static void reenable_tty_echo(void)
{
qemu_set_tty_echo(STDIN_FILENO, true);
}
int main(int argc, char **argv)
{
int readonly = 0;
int growable = 0;
const char *sopt = "hVc:d:rsnmgkt:T:";
const struct option lopt[] = {
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ "offset", 1, NULL, 'o' },
{ "cmd", 1, NULL, 'c' },
{ "read-only", 0, NULL, 'r' },
{ "snapshot", 0, NULL, 's' },
{ "nocache", 0, NULL, 'n' },
{ "misalign", 0, NULL, 'm' },
{ "growable", 0, NULL, 'g' },
{ "native-aio", 0, NULL, 'k' },
{ "discard", 1, NULL, 'd' },
{ "cache", 1, NULL, 't' },
{ "trace", 1, NULL, 'T' },
{ NULL, 0, NULL, 0 }
};
int c;
int opt_index = 0;
int flags = BDRV_O_UNMAP;
Error *local_error = NULL;
#ifdef CONFIG_POSIX
signal(SIGPIPE, SIG_IGN);
#endif
progname = basename(argv[0]);
qemu_init_exec_dir(argv[0]);
while ((c = getopt_long(argc, argv, sopt, lopt, &opt_index)) != -1) {
switch (c) {
case 's':
flags |= BDRV_O_SNAPSHOT;
break;
case 'n':
flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB;
break;
case 'd':
if (bdrv_parse_discard_flags(optarg, &flags) < 0) {
error_report("Invalid discard option: %s", optarg);
exit(1);
}
break;
case 'c':
add_user_command(optarg);
break;
case 'r':
readonly = 1;
break;
case 'm':
qemuio_misalign = true;
break;
case 'g':
growable = 1;
break;
case 'k':
flags |= BDRV_O_NATIVE_AIO;
break;
case 't':
if (bdrv_parse_cache_flags(optarg, &flags) < 0) {
error_report("Invalid cache option: %s", optarg);
exit(1);
}
break;
case 'T':
if (!trace_init_backends(optarg, NULL)) {
exit(1); /* error message will have been printed */
}
break;
case 'V':
printf("%s version %s\n", progname, QEMU_VERSION);
exit(0);
case 'h':
usage(progname);
exit(0);
default:
usage(progname);
exit(1);
}
}
if ((argc - optind) > 1) {
usage(progname);
exit(1);
}
if (qemu_init_main_loop(&local_error)) {
error_report("%s", error_get_pretty(local_error));
error_free(local_error);
exit(1);
}
bdrv_init();
/* initialize commands */
qemuio_add_command(&quit_cmd);
qemuio_add_command(&open_cmd);
qemuio_add_command(&close_cmd);
if (isatty(STDIN_FILENO)) {
readline_state = readline_init(readline_printf_func,
readline_flush_func,
NULL,
readline_completion_func);
qemu_set_tty_echo(STDIN_FILENO, false);
atexit(reenable_tty_echo);
}
/* open the device */
if (!readonly) {
flags |= BDRV_O_RDWR;
}
if ((argc - optind) == 1) {
openfile(argv[optind], flags, growable, NULL);
}
command_loop();
/*
* Make sure all outstanding requests complete before the program exits.
*/
bdrv_drain_all();
if (qemuio_bs) {
bdrv_unref(qemuio_bs);
}
g_free(readline_state);
return 0;
}