Limit the number of simultanious children
Make sure minidlna cannot fork more than 5 children, to avoid becoming a fork bomb. Reported-by: Rinat Ibragimov <ibragimovrinat@mail.ru>
This commit is contained in:
Benoît Knecht
parent
862f6b986c
commit
3995cbdac4
@ -6,7 +6,7 @@ sbin_PROGRAMS = minidlnad
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check_PROGRAMS = testupnpdescgen
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minidlnad_SOURCES = minidlna.c upnphttp.c upnpdescgen.c upnpsoap.c \
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upnpreplyparse.c minixml.c clients.c \
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getifaddr.c daemonize.c upnpglobalvars.c \
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getifaddr.c process.c upnpglobalvars.c \
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options.c minissdp.c uuid.c upnpevents.c \
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sql.c utils.c metadata.c scanner.c inotify.c \
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tivo_utils.c tivo_beacon.c tivo_commands.c \
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26
minidlna.c
26
minidlna.c
@ -86,7 +86,7 @@
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#include "utils.h"
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#include "minissdp.h"
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#include "minidlnatypes.h"
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#include "daemonize.h"
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#include "process.h"
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#include "upnpevents.h"
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#include "scanner.h"
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#include "inotify.h"
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@ -155,14 +155,6 @@ sigterm(int sig)
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quitting = 1;
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}
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static void
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sigchld(int sig)
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{
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if (!scanning)
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signal(SIGCHLD, SIG_IGN);
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waitpid(-1, NULL, WNOHANG);
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}
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static void
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sighup(int sig)
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{
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@ -369,9 +361,9 @@ rescan:
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#if USE_FORK
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scanning = 1;
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sqlite3_close(db);
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*scanner_pid = fork();
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*scanner_pid = process_fork();
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open_db(&db);
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if (!(*scanner_pid)) /* child (scanner) process */
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if (*scanner_pid == 0) /* child (scanner) process */
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{
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start_scanner();
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sqlite3_close(db);
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@ -379,6 +371,10 @@ rescan:
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freeoptions();
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exit(EXIT_SUCCESS);
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}
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else if (*scanner_pid < 0)
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{
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start_scanner();
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}
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#else
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start_scanner();
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#endif
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@ -884,7 +880,7 @@ init(int argc, char **argv)
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}
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else
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{
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pid = daemonize();
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pid = process_daemonize();
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#ifdef READYNAS
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unlink("/ramfs/.upnp-av_scan");
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path = "/var/log/upnp-av.log";
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@ -897,7 +893,7 @@ init(int argc, char **argv)
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}
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log_init(path, log_level);
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if (checkforrunning(pidfilename) < 0)
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if (process_check_if_running(pidfilename) < 0)
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{
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DPRINTF(E_ERROR, L_GENERAL, "MiniDLNA is already running. EXITING.\n");
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return 1;
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@ -923,6 +919,9 @@ init(int argc, char **argv)
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DPRINTF(E_FATAL, L_GENERAL, "Failed to set %s handler. EXITING.\n", "SIGPIPE");
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if (signal(SIGHUP, &sighup) == SIG_ERR)
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DPRINTF(E_FATAL, L_GENERAL, "Failed to set %s handler. EXITING.\n", "SIGHUP");
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sa.sa_handler = process_handle_child_termination;
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if (sigaction(SIGCHLD, &sa, NULL))
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DPRINTF(E_FATAL, L_GENERAL, "Failed to set %s handler. EXITING.\n", "SIGCHLD");
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if (writepidfile(pidfilename, pid, uid) != 0)
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pidfilename = NULL;
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@ -989,7 +988,6 @@ main(int argc, char **argv)
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ret = -1;
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}
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check_db(db, ret, &scanner_pid);
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signal(SIGCHLD, &sigchld);
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#ifdef HAVE_INOTIFY
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if( GETFLAG(INOTIFY_MASK) )
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{
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@ -1,7 +1,8 @@
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/* MiniUPnP project
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* http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
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/* Process handling
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*
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* Copyright © 2006, Thomas Bernard
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* Copyright © 2013, Benoît Knecht <benoit.knecht@fsfe.org>
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*
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* Copyright (c) 2006, Thomas Bernard
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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@ -35,48 +36,74 @@
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#include <errno.h>
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#include <string.h>
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#include <signal.h>
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#include <sys/wait.h>
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#include "daemonize.h"
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#include "process.h"
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#include "config.h"
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#include "log.h"
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static const int max_number_of_children = 5;
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static int number_of_children = 0;
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pid_t
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process_fork(void)
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{
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if (number_of_children >= max_number_of_children)
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{
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errno = EAGAIN;
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return -1;
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}
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pid_t pid = fork();
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if (pid > 0)
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++number_of_children;
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return pid;
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}
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void
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process_handle_child_termination(int signal)
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{
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waitpid(-1, NULL, WNOHANG);
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--number_of_children;
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}
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int
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daemonize(void)
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process_daemonize(void)
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{
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int pid;
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#ifndef USE_DAEMON
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int i;
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switch(fork())
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switch(process_fork())
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{
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/* fork error */
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case -1:
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perror("fork()");
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exit(1);
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/* child process */
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case 0:
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/* obtain a new process group */
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if( (pid = setsid()) < 0)
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{
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perror("setsid()");
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/* fork error */
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case -1:
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perror("fork()");
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exit(1);
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}
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/* close all descriptors */
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for (i=getdtablesize();i>=0;--i) close(i);
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/* child process */
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case 0:
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/* obtain a new process group */
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if( (pid = setsid()) < 0)
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{
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perror("setsid()");
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exit(1);
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}
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i = open("/dev/null",O_RDWR); /* open stdin */
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dup(i); /* stdout */
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dup(i); /* stderr */
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/* close all descriptors */
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for (i=getdtablesize();i>=0;--i) close(i);
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umask(027);
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chdir("/");
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i = open("/dev/null",O_RDWR); /* open stdin */
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dup(i); /* stdout */
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dup(i); /* stderr */
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break;
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/* parent process */
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default:
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exit(0);
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umask(027);
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chdir("/");
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break;
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/* parent process */
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default:
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exit(0);
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}
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#else
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if( daemon(0, 0) < 0 )
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@ -87,7 +114,7 @@ daemonize(void)
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}
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int
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checkforrunning(const char * fname)
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process_check_if_running(const char *fname)
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{
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char buffer[64];
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int pidfile;
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@ -98,9 +125,9 @@ checkforrunning(const char * fname)
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if( (pidfile = open(fname, O_RDONLY)) < 0)
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return 0;
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memset(buffer, 0, 64);
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if(read(pidfile, buffer, 63))
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{
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if( (pid = atol(buffer)) > 0)
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@ -112,9 +139,8 @@ checkforrunning(const char * fname)
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}
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}
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}
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close(pidfile);
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return 0;
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}
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@ -1,7 +1,7 @@
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/* MiniUPnP project
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* http://miniupnp.free.fr/ or http://miniupnp.tuxfamily.org/
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/* Process handling
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*
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* Copyright © 2013, Benoît Knecht <benoit.knecht@fsfe.org>
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*
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* Copyright (c) 2006, Thomas Bernard
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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@ -26,24 +26,41 @@
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef __DAEMONIZE_H__
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#define __DAEMONIZE_H__
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#ifndef __PROCESS_H__
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#define __PROCESS_H__
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#include "config.h"
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#include <unistd.h>
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/* daemonize()
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* "fork" to background, detach from terminal, etc...
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* returns: pid of the daemon, exits upon failure */
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int
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daemonize(void);
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/**
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* Fork a new child (just like fork()) but keep track of how many childs are
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* already running, and refuse fo fork if there are too many.
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* @return -1 if it couldn't fork, 0 in the child process, the pid of the
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* child process in the parent process.
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*/
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pid_t process_fork(void);
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/* checkforrunning()
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* check for another instance running
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* returns: 0 only instance
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* -1 invalid filename
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* -2 another instance running */
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int
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checkforrunning(const char * fname);
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/**
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* Handler to be called upon receiving SIGCHLD. This signal is received by the
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* parent process when a child terminates, and this handler updates the number
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* of running childs accordingly.
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* @param signal The signal number.
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*/
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void process_handle_child_termination(int signal);
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#endif
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/**
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* Daemonize the current process by forking itself and redirecting standard
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* input, standard output and standard error to /dev/null.
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* @return The pid of the process.
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*/
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int process_daemonize(void);
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/**
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* Check if the process corresponding to the pid found in the pid file is
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* running.
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* @param fname The path to the pid file.
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* @return 0 if no other instance is running, -1 if the file name is invalid,
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* -2 if another instance is running.
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*/
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int process_check_if_running(const char *fname);
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#endif // __PROCESS_H__
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13
upnphttp.c
13
upnphttp.c
@ -78,6 +78,7 @@
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#include "tivo_utils.h"
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#include "tivo_commands.h"
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#include "clients.h"
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#include "process.h"
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#include "sendfile.h"
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@ -1574,8 +1575,8 @@ SendResp_resizedimg(struct upnphttp * h, char * object)
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#if USE_FORK
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pid_t newpid = 0;
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newpid = fork();
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if( newpid )
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newpid = process_fork();
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if( newpid > 0 )
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{
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CloseSocket_upnphttp(h);
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goto resized_error;
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@ -1716,7 +1717,7 @@ SendResp_resizedimg(struct upnphttp * h, char * object)
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resized_error:
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sqlite3_free_table(result);
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#if USE_FORK
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if( !newpid )
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if( newpid == 0 )
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_exit(0);
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#endif
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}
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@ -1809,8 +1810,8 @@ SendResp_dlnafile(struct upnphttp *h, char *object)
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sqlite3_free_table(result);
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}
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#if USE_FORK
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newpid = fork();
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if( newpid )
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newpid = process_fork();
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if( newpid > 0 )
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{
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CloseSocket_upnphttp(h);
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goto error;
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@ -1951,7 +1952,7 @@ SendResp_dlnafile(struct upnphttp *h, char *object)
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CloseSocket_upnphttp(h);
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error:
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#if USE_FORK
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if( !newpid )
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if( newpid == 0 )
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_exit(0);
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#endif
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return;
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