/* Copyright (C) 2004-2018 J.F.Dockes
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef BUILDING_RECOLL
#include "autoconfig.h"
#else
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/select.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <fcntl.h>
#include <errno.h>
#include <signal.h>
#include <time.h>
#include <string.h>
#include <map>
#include <vector>
#include <string>
#include <stdexcept>
#ifdef HAVE_SPAWN_H
#ifndef __USE_GNU
#define __USE_GNU
#define undef__USE_GNU
#endif
#include <spawn.h>
#ifdef undef__USE_GNU
#undef __USE_GNU
#endif
#endif
#include "execmd.h"
#include "netcon.h"
#include "closefrom.h"
#include "smallut.h"
#include "log.h"
using namespace std;
extern char **environ;
class ExecCmd::Internal {
public:
Internal() {
sigemptyset(&m_blkcld);
}
static bool o_useVfork;
vector<string> m_env;
ExecCmdAdvise *m_advise{0};
ExecCmdProvide *m_provide{0};
bool m_killRequest{false};
int m_timeoutMs{1000};
int m_killTimeoutMs{2000};
int m_rlimit_as_mbytes{0};
string m_stderrFile;
// Pipe for data going to the command
int m_pipein[2]{-1,-1};
std::shared_ptr<NetconCli> m_tocmd;
// Pipe for data coming out
int m_pipeout[2]{-1,-1};
std::shared_ptr<NetconCli> m_fromcmd;
// Subprocess id
pid_t m_pid{-1};
// Saved sigmask
sigset_t m_blkcld;
// Reset internal state indicators. Any resources should have been
// previously freed
void reset() {
m_killRequest = false;
m_pipein[0] = m_pipein[1] = m_pipeout[0] = m_pipeout[1] = -1;
m_pid = -1;
sigemptyset(&m_blkcld);
}
// Child process code
inline void dochild(const std::string& cmd, const char **argv,
const char **envv, bool has_input, bool has_output);
};
bool ExecCmd::Internal::o_useVfork{false};
ExecCmd::ExecCmd(int)
{
m = new Internal();
if (m) {
m->reset();
}
}
void ExecCmd::setAdvise(ExecCmdAdvise *adv)
{
m->m_advise = adv;
}
void ExecCmd::setProvide(ExecCmdProvide *p)
{
m->m_provide = p;
}
void ExecCmd::setTimeout(int mS)
{
if (mS > 30) {
m->m_timeoutMs = mS;
}
}
void ExecCmd::setKillTimeout(int mS)
{
m->m_killTimeoutMs = mS;
}
void ExecCmd::setStderr(const std::string& stderrFile)
{
m->m_stderrFile = stderrFile;
}
pid_t ExecCmd::getChildPid()
{
return m->m_pid;
}
void ExecCmd::setKill()
{
m->m_killRequest = true;
}
void ExecCmd::zapChild()
{
setKill();
(void)wait();
}
bool ExecCmd::requestChildExit()
{
if (m->m_pid > 0) {
if (kill(m->m_pid, SIGTERM) == 0) {
return true;
}
}
return false;
}
/* From FreeBSD's which command */
static bool exec_is_there(const char *candidate)
{
struct stat fin;
/* XXX work around access(2) false positives for superuser */
if (access(candidate, X_OK) == 0 &&
stat(candidate, &fin) == 0 &&
S_ISREG(fin.st_mode) &&
(getuid() != 0 ||
(fin.st_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0)) {
return true;
}
return false;
}
bool ExecCmd::which(const string& cmd, string& exepath, const char* path)
{
if (cmd.empty()) {
return false;
}
if (cmd[0] == '/') {
if (exec_is_there(cmd.c_str())) {
exepath = cmd;
return true;
} else {
return false;
}
}
const char *pp;
if (path) {
pp = path;
} else {
pp = getenv("PATH");
}
if (pp == 0) {
return false;
}
vector<string> pels;
stringToTokens(pp, pels, ":");
for (vector<string>::iterator it = pels.begin(); it != pels.end(); it++) {
if (it->empty()) {
*it = ".";
}
string candidate = (it->empty() ? string(".") : *it) + "/" + cmd;
if (exec_is_there(candidate.c_str())) {
exepath = candidate;
return true;
}
}
return false;
}
void ExecCmd::useVfork(bool on)
{
// Just in case: there are competent people who believe that the
// dynamic linker can sometimes deadlock if execve() is resolved
// inside the vfork/exec window. Make sure it's done now. If "/" is
// an executable file, we have a problem.
const char *argv[] = {"/", 0};
execve("/", (char *const *)argv, environ);
Internal::o_useVfork = on;
}
void ExecCmd::putenv(const string& ea)
{
m->m_env.push_back(ea);
}
void ExecCmd::putenv(const string& name, const string& value)
{
string ea = name + "=" + value;
putenv(ea);
}
static void msleep(int millis)
{
struct timespec spec;
spec.tv_sec = millis / 1000;
spec.tv_nsec = (millis % 1000) * 1000000;
nanosleep(&spec, 0);
}
/** A resource manager to ensure that execcmd cleans up if an exception is
* raised in the callback, or at different places on errors occurring
* during method executions */
class ExecCmdRsrc {
public:
ExecCmdRsrc(ExecCmd::Internal *parent)
: m_parent(parent), m_active(true) {
}
void inactivate() {
m_active = false;
}
~ExecCmdRsrc() {
if (!m_active || !m_parent) {
return;
}
LOGDEB1("~ExecCmdRsrc: working. mypid: " << getpid() << "\n");
// Better to close the descs first in case the child is waiting in read
if (m_parent->m_pipein[0] >= 0) {
close(m_parent->m_pipein[0]);
}
if (m_parent->m_pipein[1] >= 0) {
close(m_parent->m_pipein[1]);
}
if (m_parent->m_pipeout[0] >= 0) {
close(m_parent->m_pipeout[0]);
}
if (m_parent->m_pipeout[1] >= 0) {
close(m_parent->m_pipeout[1]);
}
// It's apparently possible for m_pid to be > 0 and getpgid to fail. In
// this case, we have to conclude that the child process does
// not exist. Not too sure what causes this, but the previous code
// definitely tried to call killpg(-1,) from time to time.
pid_t grp;
if (m_parent->m_pid > 0 && (grp = getpgid(m_parent->m_pid)) > 0) {
LOGDEB("ExecCmd: pid " << m_parent->m_pid << " killpg(" << grp <<
", SIGTERM)\n");
int ret = killpg(grp, SIGTERM);
if (ret == 0) {
int ms_slept{0};
for (int i = 0; ; i++) {
int tosleep = i == 0 ? 5 : (i == 1 ? 100 : 1000);
msleep(tosleep);
ms_slept += tosleep;
int status;
(void)waitpid(m_parent->m_pid, &status, WNOHANG);
if (kill(m_parent->m_pid, 0) != 0) {
break;
}
// killtimeout == -1 -> never KILL
if (m_parent->m_killTimeoutMs >= 0 &&
ms_slept >= m_parent->m_killTimeoutMs) {
LOGDEB("ExecCmd: killpg(" << grp << ", SIGKILL)\n");
killpg(grp, SIGKILL);
(void)waitpid(m_parent->m_pid, &status, WNOHANG);
break;
}
}
} else {
LOGERR("ExecCmd: error killing process group " << (grp) <<
": " << errno << "\n");
}
}
m_parent->m_tocmd.reset();
m_parent->m_fromcmd.reset();
pthread_sigmask(SIG_UNBLOCK, &m_parent->m_blkcld, 0);
m_parent->reset();
}
private:
ExecCmd::Internal *m_parent{nullptr};
bool m_active{false};
};
ExecCmd::~ExecCmd()
{
if (m) {
ExecCmdRsrc r(m);
}
if (m) {
delete m;
m = nullptr;
}
}
// In child process. Set up pipes and exec command.
// This must not return. _exit() on error.
// *** This can be called after a vfork, so no modification of the
// process memory at all is allowed ***
// The LOGXX calls should not be there, but they occur only after "impossible"
// errors, which we would most definitely want to have a hint about.
//
// Note that any of the LOGXX calls could block on a mutex set in the
// father process, so that only absolutely exceptional conditions,
// should be logged, for debugging and post-mortem purposes
// If one of the calls block, the problem manifests itself by 20mn
// (filter timeout) of looping on "ExecCmd::doexec: selectloop
// returned 1', because the father is waiting on the read descriptor
inline void ExecCmd::Internal::dochild(const string& cmd, const char **argv,
const char **envv,
bool has_input, bool has_output)
{
// Start our own process group
if (setpgid(0, 0)) {
LOGINFO("ExecCmd::DOCHILD: setpgid(0, 0) failed: errno " << errno <<
"\n");
}
// Restore SIGTERM to default. Really, signal handling should be
// specified when creating the execmd, there might be other
// signals to reset. Resetting SIGTERM helps Recoll get rid of its
// filter children for now though. To be fixed one day...
// Note that resetting to SIG_DFL is a portable use of
// signal(). No need for sigaction() here.
// There is supposedely a risk of problems if another thread was
// calling a signal-affecting function when vfork was called. This
// seems acceptable though as no self-respecting thread is going
// to mess with the global process signal disposition.
if (signal(SIGTERM, SIG_DFL) == SIG_ERR) {
//LOGERR("ExecCmd::DOCHILD: signal() failed, errno " << errno << "\n");
}
sigset_t sset;
sigfillset(&sset);
pthread_sigmask(SIG_UNBLOCK, &sset, 0);
sigprocmask(SIG_UNBLOCK, &sset, 0);
#ifdef HAVE_SETRLIMIT
#if defined RLIMIT_AS || defined RLIMIT_VMEM || defined RLIMIT_DATA
if (m_rlimit_as_mbytes > 2000 && sizeof(rlim_t) < 8) {
// Impossible limit, don't use it
m_rlimit_as_mbytes = 0;
}
if (m_rlimit_as_mbytes > 0) {
struct rlimit ram_limit = {
static_cast<rlim_t>(m_rlimit_as_mbytes * 1024 * 1024),
RLIM_INFINITY
};
int resource;
// RLIMIT_AS and RLIMIT_VMEM are usually synonyms when VMEM is
// defined. RLIMIT_AS is Posix. Both don't really do what we
// want, because they count e.g. shared lib mappings, which we
// don't really care about.
// RLIMIT_DATA only limits the data segment. Modern mallocs
// use mmap and will not be bound. (Otoh if we only have this,
// we're probably not modern).
// So we're unsatisfied either way.
#ifdef RLIMIT_AS
resource = RLIMIT_AS;
#elif defined RLIMIT_VMEM
resource = RLIMIT_VMEM;
#else
resource = RLIMIT_DATA;
#endif
setrlimit(resource, &ram_limit);
}
#endif
#endif // have_setrlimit
if (has_input) {
close(m_pipein[1]);
if (m_pipein[0] != 0) {
dup2(m_pipein[0], 0);
close(m_pipein[0]);
}
}
if (has_output) {
close(m_pipeout[0]);
if (m_pipeout[1] != 1) {
if (dup2(m_pipeout[1], 1) < 0) {
LOGERR("ExecCmd::DOCHILD: dup2() failed. errno " <<
errno << "\n");
}
if (close(m_pipeout[1]) < 0) {
LOGERR("ExecCmd::DOCHILD: close() failed. errno " <<
errno << "\n");
}
}
}
// Do we need to redirect stderr ?
if (!m_stderrFile.empty()) {
int fd = open(m_stderrFile.c_str(), O_WRONLY | O_CREAT
#ifdef O_APPEND
| O_APPEND
#endif
, 0600);
if (fd < 0) {
close(2);
} else {
if (fd != 2) {
dup2(fd, 2);
}
lseek(2, 0, 2);
}
}
// Close all descriptors except 0,1,2
libclf_closefrom(3);
execve(cmd.c_str(), (char *const*)argv, (char *const*)envv);
// Hu ho. This should never have happened as we checked the
// existence of the executable before calling dochild... Until we
// did this check, this was the chief cause of LOG mutex deadlock
LOGERR("ExecCmd::DOCHILD: execve(" << cmd << ") failed. errno " <<
errno << "\n");
_exit(127);
}
void ExecCmd::setrlimit_as(int mbytes)
{
m->m_rlimit_as_mbytes = mbytes;
}
int ExecCmd::startExec(const string& cmd, const vector<string>& args,
bool has_input, bool has_output)
{
{
// Debug and logging
string command = cmd + " ";
for (vector<string>::const_iterator it = args.begin();
it != args.end(); it++) {
command += "{" + *it + "} ";
}
LOGDEB("ExecCmd::startExec: (" << has_input << "|" << has_output <<
") " << command << "\n");
}
// The resource manager ensures resources are freed if we return early
ExecCmdRsrc e(m);
if (has_input && pipe(m->m_pipein) < 0) {
LOGERR("ExecCmd::startExec: pipe(2) failed. errno " << errno << "\n" );
return -1;
}
if (has_output && pipe(m->m_pipeout) < 0) {
LOGERR("ExecCmd::startExec: pipe(2) failed. errno " << errno << "\n");
return -1;
}
//////////// vfork setup section
// We do here things that we could/should do after a fork(), but
// not a vfork(). Does no harm to do it here in both cases, except
// that it needs cleanup (as compared to doing it just before
// exec()).
// Allocate arg vector (2 more for arg0 + final 0)
typedef const char *Ccharp;
Ccharp *argv;
argv = (Ccharp *)malloc((args.size() + 2) * sizeof(char *));
if (argv == 0) {
LOGERR("ExecCmd::doexec: malloc() failed. errno " << errno << "\n");
return -1;
}
// Fill up argv
argv[0] = cmd.c_str();
int i = 1;
vector<string>::const_iterator it;
for (it = args.begin(); it != args.end(); it++) {
argv[i++] = it->c_str();
}
argv[i] = 0;
// Environment. We first merge our environment and the specified
// variables in a map<string,string>, overriding existing values,
// then generate an appropriate char*[]
Ccharp *envv;
map<string, string> envmap;
for (int i = 0; environ[i] != 0; i++) {
string entry(environ[i]);
string::size_type eqpos = entry.find_first_of("=");
if (eqpos == string::npos) {
continue;
}
envmap[entry.substr(0, eqpos)] = entry.substr(eqpos+1);
}
for (const auto& entry : m->m_env) {
string::size_type eqpos = entry.find_first_of("=");
if (eqpos == string::npos) {
continue;
}
envmap[entry.substr(0, eqpos)] = entry.substr(eqpos+1);
}
// Allocate space for the array + string storage in one block.
unsigned int allocsize = (envmap.size() + 2) * sizeof(char *);
for (const auto& it : envmap) {
allocsize += it.first.size() + 1 + it.second.size() + 1;
}
envv = (Ccharp *)malloc(allocsize);
if (envv == 0) {
LOGERR("ExecCmd::doexec: malloc() failed. errno " << errno << "\n");
free(argv);
return -1;
}
// Copy to new env array
i = 0;
char *cp = ((char *)envv) + (envmap.size() + 2) * sizeof(char *);
for (const auto& it : envmap) {
strcpy(cp, (it.first + "=" + it.second).c_str());
envv[i++] = cp;
cp += it.first.size() + 1 + it.second.size() + 1;
}
envv[i++] = 0;
// As we are going to use execve, not execvp, do the PATH thing.
string exe;
if (!which(cmd, exe)) {
LOGERR("ExecCmd::startExec: " << cmd << " not found\n");
free(argv);
free(envv);
return 127 << 8;
}
//////////////////////////////// End vfork child prepare section.
#if HAVE_POSIX_SPAWN && USE_POSIX_SPAWN
// Note that posix_spawn provides no way to setrlimit() the child.
{
posix_spawnattr_t attrs;
posix_spawnattr_init(&attrs);
short flags;
posix_spawnattr_getflags(&attrs, &flags);
flags |= POSIX_SPAWN_USEVFORK;
posix_spawnattr_setpgroup(&attrs, 0);
flags |= POSIX_SPAWN_SETPGROUP;
sigset_t sset;
sigemptyset(&sset);
posix_spawnattr_setsigmask(&attrs, &sset);
flags |= POSIX_SPAWN_SETSIGMASK;
sigemptyset(&sset);
sigaddset(&sset, SIGTERM);
posix_spawnattr_setsigdefault(&attrs, &sset);
flags |= POSIX_SPAWN_SETSIGDEF;
posix_spawnattr_setflags(&attrs, flags);
posix_spawn_file_actions_t facts;
posix_spawn_file_actions_init(&facts);
if (has_input) {
posix_spawn_file_actions_addclose(&facts, m->m_pipein[1]);
if (m->m_pipein[0] != 0) {
posix_spawn_file_actions_adddup2(&facts, m->m_pipein[0], 0);
posix_spawn_file_actions_addclose(&facts, m->m_pipein[0]);
}
}
if (has_output) {
posix_spawn_file_actions_addclose(&facts, m->m_pipeout[0]);
if (m->m_pipeout[1] != 1) {
posix_spawn_file_actions_adddup2(&facts, m->m_pipeout[1], 1);
posix_spawn_file_actions_addclose(&facts, m->m_pipeout[1]);
}
}
// Do we need to redirect stderr ?
if (!m->m_stderrFile.empty()) {
int oflags = O_WRONLY | O_CREAT;
#ifdef O_APPEND
oflags |= O_APPEND;
#endif
posix_spawn_file_actions_addopen(&facts, 2, m->m_stderrFile.c_str(),
oflags, 0600);
}
LOGDEB1("using SPAWN\n");
// posix_spawn() does not have any standard way to ask for
// calling closefrom(). Afaik there is a solaris extension for this,
// but let's just add all fds
for (int i = 3; i < libclf_maxfd(); i++) {
posix_spawn_file_actions_addclose(&facts, i);
}
int ret = posix_spawn(&m->m_pid, exe.c_str(), &facts, &attrs,
(char *const *)argv, (char *const *)envv);
posix_spawnattr_destroy(&attrs);
posix_spawn_file_actions_destroy(&facts);
if (ret) {
LOGERR("ExecCmd::startExec: posix_spawn() failed. errno " << ret <<
"\n");
return -1;
}
}
#else
if (Internal::o_useVfork) {
LOGDEB1("using VFORK\n");
m->m_pid = vfork();
} else {
LOGDEB1("using FORK\n");
m->m_pid = fork();
}
if (m->m_pid < 0) {
LOGERR("ExecCmd::startExec: fork(2) failed. errno " << errno << "\n");
return -1;
}
if (m->m_pid == 0) {
// e.inactivate() is not needed. As we do not return, the call
// stack won't be unwound and destructors of local objects
// won't be called.
m->dochild(exe, argv, envv, has_input, has_output);
// dochild does not return. Just in case...
_exit(1);
}
#endif
// Father process
////////////////////
// Vfork cleanup section
free(argv);
free(envv);
///////////////////
// Set the process group for the child. This is also done in the
// child process see wikipedia(Process_group)
if (setpgid(m->m_pid, m->m_pid)) {
// This can fail with EACCES if the son has already done execve
// (linux at least)
LOGDEB2("ExecCmd: father setpgid(son)(" << m->m_pid << "," <<
m->m_pid << ") errno " << errno << " (ok)\n");
}
sigemptyset(&m->m_blkcld);
sigaddset(&m->m_blkcld, SIGCHLD);
pthread_sigmask(SIG_BLOCK, &m->m_blkcld, 0);
if (has_input) {
close(m->m_pipein[0]);
m->m_pipein[0] = -1;
NetconCli *iclicon = new NetconCli();
iclicon->setconn(m->m_pipein[1]);
m->m_tocmd = std::shared_ptr<NetconCli>(iclicon);
}
if (has_output) {
close(m->m_pipeout[1]);
m->m_pipeout[1] = -1;
NetconCli *oclicon = new NetconCli();
oclicon->setconn(m->m_pipeout[0]);
m->m_fromcmd = std::shared_ptr<NetconCli>(oclicon);
}
/* Don't want to undo what we just did ! */
e.inactivate();
return 0;
}
// Netcon callback. Send data to the command's input
class ExecWriter : public NetconWorker {
public:
ExecWriter(const string *input, ExecCmdProvide *provide,
ExecCmd::Internal *parent)
: m_cmd(parent), m_input(input), m_cnt(0), m_provide(provide) {
}
void shutdown() {
close(m_cmd->m_pipein[1]);
m_cmd->m_pipein[1] = -1;
m_cmd->m_tocmd.reset();
}
virtual int data(NetconData *con, Netcon::Event reason) {
if (!m_input) {
return -1;
}
LOGDEB1("ExecWriter: input m_cnt " << m_cnt << " input length " <<
m_input->length() << "\n");
if (m_cnt >= m_input->length()) {
// Fd ready for more but we got none. Try to get data, else
// shutdown;
if (!m_provide) {
shutdown();
return 0;
}
m_provide->newData();
if (m_input->empty()) {
shutdown();
return 0;
} else {
// Ready with new buffer, reset use count
m_cnt = 0;
}
LOGDEB2("ExecWriter: provide m_cnt " << m_cnt <<
" input length " << m_input->length() << "\n");
}
int ret = con->send(m_input->c_str() + m_cnt,
m_input->length() - m_cnt);
LOGDEB2("ExecWriter: wrote " << (ret) << " to command\n");
if (ret <= 0) {
LOGERR("ExecWriter: data: can't write\n");
return -1;
}
m_cnt += ret;
return ret;
}
private:
ExecCmd::Internal *m_cmd;
const string *m_input;
unsigned int m_cnt; // Current offset inside m_input
ExecCmdProvide *m_provide;
};
// Netcon callback. Get data from the command output.
class ExecReader : public NetconWorker {
public:
ExecReader(string *output, ExecCmdAdvise *advise)
: m_output(output), m_advise(advise) {
}
virtual int data(NetconData *con, Netcon::Event reason) {
char buf[8192];
int n = con->receive(buf, 8192);
LOGDEB1("ExecReader: got " << (n) << " from command\n");
if (n < 0) {
LOGERR("ExecCmd::doexec: receive failed. errno " << errno << "\n");
} else if (n > 0) {
m_output->append(buf, n);
if (m_advise) {
m_advise->newData(n);
}
} // else n == 0, just return
return n;
}
private:
string *m_output;
ExecCmdAdvise *m_advise;
};
int ExecCmd::doexec(const string& cmd, const vector<string>& args,
const string *input, string *output)
{
int status = startExec(cmd, args, input != 0, output != 0);
if (status) {
return status;
}
// Cleanup in case we return early
ExecCmdRsrc e(m);
SelectLoop myloop;
int ret = 0;
if (input || output) {
// Setup output
if (output) {
NetconCli *oclicon = m->m_fromcmd.get();
if (!oclicon) {
LOGERR("ExecCmd::doexec: no connection from command\n");
return -1;
}
oclicon->setcallback(std::shared_ptr<NetconWorker>
(new ExecReader(output, m->m_advise)));
myloop.addselcon(m->m_fromcmd, Netcon::NETCONPOLL_READ);
// Give up ownership
m->m_fromcmd.reset();
}
// Setup input
if (input) {
NetconCli *iclicon = m->m_tocmd.get();
if (!iclicon) {
LOGERR("ExecCmd::doexec: no connection from command\n");
return -1;
}
iclicon->setcallback(std::shared_ptr<NetconWorker>
(new ExecWriter(input, m->m_provide, m)));
myloop.addselcon(m->m_tocmd, Netcon::NETCONPOLL_WRITE);
// Give up ownership
m->m_tocmd.reset();
}
// Do the actual reading/writing/waiting
myloop.setperiodichandler(0, 0, m->m_timeoutMs);
while ((ret = myloop.doLoop()) > 0) {
LOGDEB("ExecCmd::doexec: selectloop returned " << (ret) << "\n");
if (m->m_advise) {
m->m_advise->newData(0);
}
if (m->m_killRequest) {
LOGINFO("ExecCmd::doexec: cancel request\n");
break;
}
}
LOGDEB0("ExecCmd::doexec: selectloop returned " << (ret) << "\n");
// Check for interrupt request: we won't want to waitpid()
if (m->m_advise) {
m->m_advise->newData(0);
}
// The netcons don't take ownership of the fds: we have to close them
// (have to do it before wait, this may be the signal the child is
// waiting for exiting).
if (input) {
close(m->m_pipein[1]);
m->m_pipein[1] = -1;
}
if (output) {
close(m->m_pipeout[0]);
m->m_pipeout[0] = -1;
}
}
// Normal return: deactivate cleaner, wait() will do the cleanup
e.inactivate();
int ret1 = ExecCmd::wait();
if (ret) {
return -1;
}
return ret1;
}
int ExecCmd::send(const string& data)
{
NetconCli *con = m->m_tocmd.get();
if (con == 0) {
LOGERR("ExecCmd::send: outpipe is closed\n");
return -1;
}
unsigned int nwritten = 0;
while (nwritten < data.length()) {
if (m->m_killRequest) {
break;
}
int n = con->send(data.c_str() + nwritten, data.length() - nwritten);
if (n < 0) {
LOGERR("ExecCmd::send: send failed\n");
return -1;
}
nwritten += n;
}
return nwritten;
}
int ExecCmd::receive(string& data, int cnt)
{
NetconCli *con = m->m_fromcmd.get();
if (con == 0) {
LOGERR("ExecCmd::receive: inpipe is closed\n");
return -1;
}
const int BS = 4096;
char buf[BS];
int ntot = 0;
do {
int toread = cnt > 0 ? MIN(cnt - ntot, BS) : BS;
int n = con->receive(buf, toread);
if (n < 0) {
LOGERR("ExecCmd::receive: error\n");
return -1;
} else if (n > 0) {
ntot += n;
data.append(buf, n);
} else {
LOGDEB("ExecCmd::receive: got 0\n");
break;
}
} while (cnt > 0 && ntot < cnt);
return ntot;
}
int ExecCmd::getline(string& data)
{
NetconCli *con = m->m_fromcmd.get();
if (con == 0) {
LOGERR("ExecCmd::receive: inpipe is closed\n");
return -1;
}
const int BS = 1024;
char buf[BS];
int timeosecs = m->m_timeoutMs / 1000;
if (timeosecs == 0) {
timeosecs = 1;
}
// Note that we only go once through here, except in case of
// timeout, which is why I think that the goto is more expressive
// than a loop
again:
int n = con->getline(buf, BS, timeosecs);
if (n < 0) {
if (con->timedout()) {
LOGDEB0("ExecCmd::getline: select timeout, report and retry\n");
if (m->m_advise) {
m->m_advise->newData(0);
}
goto again;
}
LOGERR("ExecCmd::getline: error\n");
} else if (n > 0) {
data.append(buf, n);
} else {
LOGDEB("ExecCmd::getline: got 0\n");
}
return n;
}
class GetlineWatchdog : public ExecCmdAdvise {
public:
GetlineWatchdog(int secs) : m_secs(secs), tstart(time(0)) {}
void newData(int cnt) {
if (time(0) - tstart >= m_secs) {
throw std::runtime_error("getline timeout");
}
}
int m_secs;
time_t tstart;
};
int ExecCmd::getline(string& data, int timeosecs)
{
GetlineWatchdog gwd(timeosecs);
setAdvise(&gwd);
try {
return getline(data);
} catch (...) {
return -1;
}
}
// Wait for command status and clean up all resources.
// We would like to avoid blocking here too, but there is no simple
// way to do this. The 2 possible approaches would be to:
// - Use signals (alarm), waitpid() is interruptible. but signals and
// threads... This would need a specialized thread, inter-thread comms etc.
// - Use an intermediary process when starting the command. The
// process forks a timer process, and the real command, then calls
// a blocking waitpid on all at the end, and is guaranteed to get
// at least the timer process status, thus yielding a select()
// equivalent. This is bad too, because the timeout is on the whole
// exec, not just the wait
// Just calling waitpid() with WNOHANG with a sleep() between tries
// does not work: the first waitpid() usually comes too early and
// reaps nothing, resulting in almost always one sleep() or more.
//
// So no timeout here. This has not been a problem in practise inside recoll.
// In case of need, using a semi-busy loop with short sleeps
// increasing from a few mS might work without creating too much
// overhead.
int ExecCmd::wait()
{
ExecCmdRsrc e(m);
int status = -1;
if (!m->m_killRequest && m->m_pid > 0) {
if (waitpid(m->m_pid, &status, 0) < 0) {
LOGERR("ExecCmd::waitpid: returned -1 errno " << errno << "\n");
status = -1;
}
LOGDEB("ExecCmd::wait: got status 0x" << (status) << "\n");
m->m_pid = -1;
}
// Let the ExecCmdRsrc cleanup, it will do the killing/waiting if needed
return status;
}
bool ExecCmd::maybereap(int *status)
{
ExecCmdRsrc e(m);
*status = -1;
if (m->m_pid <= 0) {
// Already waited for ??
return true;
}
pid_t pid = waitpid(m->m_pid, status, WNOHANG);
if (pid < 0) {
LOGERR("ExecCmd::maybereap: returned -1 errno " << errno << "\n");
m->m_pid = -1;
return true;
} else if (pid == 0) {
LOGDEB1("ExecCmd::maybereap: not exited yet\n");
e.inactivate();
return false;
} else {
LOGDEB("ExecCmd::maybereap: got status 0x" << (status) << "\n");
m->m_pid = -1;
return true;
}
}
// Static
bool ExecCmd::backtick(const vector<string> cmd, string& out)
{
if (cmd.empty()) {
LOGERR("ExecCmd::backtick: empty command\n");
return false;
}
vector<string>::const_iterator it = cmd.begin();
it++;
vector<string> args(it, cmd.end());
ExecCmd mexec;
int status = mexec.doexec(*cmd.begin(), args, 0, &out);
return status == 0;
}
/// ReExec class methods ///////////////////////////////////////////////////
ReExec::ReExec(int argc, char *args[])
{
init(argc, args);
}
void ReExec::init(int argc, char *args[])
{
for (int i = 0; i < argc; i++) {
m_argv.push_back(args[i]);
}
m_cfd = open(".", 0);
char *cd = getcwd(0, 0);
if (cd) {
m_curdir = cd;
}
free(cd);
}
void ReExec::insertArgs(const vector<string>& args, int idx)
{
vector<string>::iterator it, cit;
unsigned int cmpoffset = (unsigned int) - 1;
if (idx == -1 || string::size_type(idx) >= m_argv.size()) {
it = m_argv.end();
if (m_argv.size() >= args.size()) {
cmpoffset = m_argv.size() - args.size();
}
} else {
it = m_argv.begin() + idx;
if (idx + args.size() <= m_argv.size()) {
cmpoffset = idx;
}
}
// Check that the option is not already there
if (cmpoffset != (unsigned int) - 1) {
bool allsame = true;
for (unsigned int i = 0; i < args.size(); i++) {
if (m_argv[cmpoffset + i] != args[i]) {
allsame = false;
break;
}
}
if (allsame) {
return;
}
}
m_argv.insert(it, args.begin(), args.end());
}
void ReExec::removeArg(const string& arg)
{
for (vector<string>::iterator it = m_argv.begin();
it != m_argv.end(); it++) {
if (*it == arg) {
it = m_argv.erase(it);
}
}
}
// Reexecute myself, as close as possible to the initial exec
void ReExec::reexec()
{
#if 0
char *cwd;
cwd = getcwd(0, 0);
FILE *fp = stdout; //fopen("/tmp/exectrace", "w");
if (fp) {
fprintf(fp, "reexec: pwd: [%s] args: ", cwd ? cwd : "getcwd failed");
for (vector<string>::const_iterator it = m_argv.begin();
it != m_argv.end(); it++) {
fprintf(fp, "[%s] ", it->c_str());
}
fprintf(fp, "\n");
}
#endif
// Execute the atexit funcs
while (!m_atexitfuncs.empty()) {
(m_atexitfuncs.top())();
m_atexitfuncs.pop();
}
// Try to get back to the initial working directory
if (m_cfd < 0 || fchdir(m_cfd) < 0) {
LOGINFO("ReExec::reexec: fchdir failed, trying chdir\n");
if (!m_curdir.empty() && chdir(m_curdir.c_str())) {
LOGERR("ReExec::reexec: chdir failed\n");
}
}
// Close all descriptors except 0,1,2
libclf_closefrom(3);
// Allocate arg vector (1 more for final 0)
typedef const char *Ccharp;
Ccharp *argv;
argv = (Ccharp *)malloc((m_argv.size() + 1) * sizeof(char *));
if (argv == 0) {
LOGERR("ExecCmd::doexec: malloc() failed. errno " << errno << "\n");
return;
}
// Fill up argv
int i = 0;
vector<string>::const_iterator it;
for (it = m_argv.begin(); it != m_argv.end(); it++) {
argv[i++] = it->c_str();
}
argv[i] = 0;
execvp(m_argv[0].c_str(), (char *const*)argv);
}