libvirt/tests/commandhelper.c
Daniel P. Berrangé 946c815024 tests: don't mix FILE* and UNIX FD I/O on same stream
There is currently a hang in test27 that exhibits itself on FreeBSD 11.4
only. The behaviour is that virCommandProcessIO gets POLLIN on the
FD for stdout, but read() blocks. Meanwhile commandtest also blocks
in write for stderr because the pipe buffers are full.

This fix in commandhelper likely does not really address the root cause
just hides it due to the buffering done by FILE *. Mixing UNIX FD I/O
and FILE * I/O is bad practice regardless.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2020-09-22 10:45:33 +01:00

254 lines
6.5 KiB
C

/*
* commandhelper.c: Auxiliary program for commandtest
*
* Copyright (C) 2010-2014 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library. If not, see
* <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#define VIR_NO_GLIB_STDIO /* This file intentionally does not link to libvirt/glib */
#include "testutils.h"
#ifndef WIN32
# include <poll.h>
/* Some UNIX lack it in headers & it doesn't hurt to redeclare */
extern char **environ;
# define VIR_FROM_THIS VIR_FROM_NONE
static int envsort(const void *a, const void *b)
{
const char *const*astrptr = a;
const char *const*bstrptr = b;
const char *astr = *astrptr;
const char *bstr = *bstrptr;
char *aeq = strchr(astr, '=');
char *beq = strchr(bstr, '=');
char *akey;
char *bkey;
int ret;
if (!(akey = strndup(astr, aeq - astr)))
abort();
if (!(bkey = strndup(bstr, beq - bstr)))
abort();
ret = strcmp(akey, bkey);
free(akey);
free(bkey);
return ret;
}
int main(int argc, char **argv) {
size_t i, n;
int open_max;
char **origenv;
char **newenv = NULL;
char *cwd;
FILE *log = fopen(abs_builddir "/commandhelper.log", "w");
int ret = EXIT_FAILURE;
int readfds[3] = { STDIN_FILENO, };
int numreadfds = 1;
struct pollfd fds[3];
int numpollfds = 0;
char *buffers[3] = {NULL, NULL, NULL};
size_t buflen[3] = {0, 0, 0};
char c;
bool daemonize_check = false;
size_t daemonize_retries = 3;
char buf[1024];
ssize_t got;
if (!log)
return ret;
for (i = 1; i < argc; i++) {
fprintf(log, "ARG:%s\n", argv[i]);
if (STREQ(argv[i - 1], "--readfd") &&
sscanf(argv[i], "%u%c", &readfds[numreadfds++], &c) != 1) {
printf("Could not parse fd %s\n", argv[i]);
goto cleanup;
} else if (STREQ(argv[i], "--check-daemonize")) {
daemonize_check = true;
}
}
origenv = environ;
n = 0;
while (*origenv != NULL) {
n++;
origenv++;
}
if (!(newenv = malloc(sizeof(*newenv) * n)))
abort();
origenv = environ;
n = i = 0;
while (*origenv != NULL) {
newenv[i++] = *origenv;
n++;
origenv++;
}
qsort(newenv, n, sizeof(newenv[0]), envsort);
for (i = 0; i < n; i++) {
/* Ignore the variables used to instruct the loader into
* behaving differently, as they could throw the tests off. */
if (!STRPREFIX(newenv[i], "LD_"))
fprintf(log, "ENV:%s\n", newenv[i]);
}
open_max = sysconf(_SC_OPEN_MAX);
if (open_max < 0)
goto cleanup;
for (i = 0; i < open_max; i++) {
int f;
int closed;
if (i == fileno(log))
continue;
closed = fcntl(i, F_GETFD, &f) == -1 &&
errno == EBADF;
if (!closed)
fprintf(log, "FD:%zu\n", i);
}
while (true) {
bool daemonized = getpgrp() != getppid();
if (daemonize_check && !daemonized && daemonize_retries-- > 0) {
usleep(100*1000);
continue;
}
fprintf(log, "DAEMON:%s\n", daemonized ? "yes" : "no");
break;
}
if (!(cwd = getcwd(NULL, 0)))
goto cleanup;
if (strlen(cwd) > strlen(".../commanddata") &&
STREQ(cwd + strlen(cwd) - strlen("/commanddata"), "/commanddata"))
strcpy(cwd, ".../commanddata");
# ifdef __APPLE__
char *noprivateprefix = NULL;
if (strstr(cwd, "/private"))
noprivateprefix = cwd + strlen("/private");
else
noprivateprefix = cwd;
fprintf(log, "CWD:%s\n", noprivateprefix);
# else
fprintf(log, "CWD:%s\n", cwd);
# endif
free(cwd);
fprintf(log, "UMASK:%04o\n", umask(0));
if (argc > 1 && STREQ(argv[1], "--close-stdin")) {
if (freopen("/dev/null", "r", stdin) != stdin)
goto cleanup;
usleep(100*1000);
}
fprintf(stdout, "BEGIN STDOUT\n");
fflush(stdout);
fprintf(stderr, "BEGIN STDERR\n");
fflush(stderr);
for (i = 0; i < numreadfds; i++) {
fds[numpollfds].fd = readfds[i];
fds[numpollfds].events = POLLIN;
fds[numpollfds].revents = 0;
numpollfds++;
}
for (;;) {
unsigned ctr = 0;
if (poll(fds, numpollfds, -1) < 0) {
printf("poll failed: %s\n", strerror(errno));
goto cleanup;
}
for (i = 0; i < numpollfds; i++) {
if (fds[i].revents & (POLLIN | POLLHUP | POLLERR)) {
fds[i].revents = 0;
got = read(fds[i].fd, buf, sizeof(buf));
if (got < 0)
goto cleanup;
if (got == 0) {
/* do not want to hear from this fd anymore */
fds[i].events = 0;
} else {
buffers[i] = realloc(buffers[i], buflen[i] + got);
if (!buf[i]) {
fprintf(stdout, "Out of memory!\n");
goto cleanup;
}
memcpy(buffers[i] + buflen[i], buf, got);
buflen[i] += got;
}
}
}
for (i = 0; i < numpollfds; i++) {
if (fds[i].events) {
ctr++;
break;
}
}
if (ctr == 0)
break;
}
for (i = 0; i < numpollfds; i++) {
if (fwrite(buffers[i], 1, buflen[i], stdout) != buflen[i])
goto cleanup;
if (fwrite(buffers[i], 1, buflen[i], stderr) != buflen[i])
goto cleanup;
}
fprintf(stdout, "END STDOUT\n");
fflush(stdout);
fprintf(stderr, "END STDERR\n");
fflush(stderr);
ret = EXIT_SUCCESS;
cleanup:
for (i = 0; i < G_N_ELEMENTS(buffers); i++)
free(buffers[i]);
fclose(log);
free(newenv);
return ret;
}
#else
int
main(void)
{
return EXIT_AM_SKIP;
}
#endif