Skip to content

Commit

Permalink
ccan: import ccan/daemonize.
Browse files Browse the repository at this point in the history
Signed-off-by: Rusty Russell <[email protected]>
  • Loading branch information
rustyrussell authored and cdecker committed Feb 16, 2018
1 parent ccd0e5d commit c5cc5c5
Show file tree
Hide file tree
Showing 6 changed files with 201 additions and 0 deletions.
4 changes: 4 additions & 0 deletions Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -47,6 +47,7 @@ CCAN_OBJS := \
ccan-crypto-sha256.o \
ccan-crypto-shachain.o \
ccan-crypto-siphash24.o \
ccan-daemonize.o \
ccan-err.o \
ccan-fdpass.o \
ccan-htable.o \
Expand Down Expand Up @@ -97,6 +98,7 @@ CCAN_HEADERS := \
$(CCANDIR)/ccan/crypto/sha256/sha256.h \
$(CCANDIR)/ccan/crypto/shachain/shachain.h \
$(CCANDIR)/ccan/crypto/siphash24/siphash24.h \
$(CCANDIR)/ccan/daemonize/daemonize.h \
$(CCANDIR)/ccan/endian/endian.h \
$(CCANDIR)/ccan/err/err.h \
$(CCANDIR)/ccan/fdpass/fdpass.h \
Expand Down Expand Up @@ -450,6 +452,8 @@ ccan-opt-parse.o: $(CCANDIR)/ccan/opt/parse.c
$(CC) $(CFLAGS) -c -o $@ $<
ccan-opt-usage.o: $(CCANDIR)/ccan/opt/usage.c
$(CC) $(CFLAGS) -c -o $@ $<
ccan-daemonize.o: $(CCANDIR)/ccan/daemonize/daemonize.c
$(CC) $(CFLAGS) -c -o $@ $<
ccan-err.o: $(CCANDIR)/ccan/err/err.c
$(CC) $(CFLAGS) -c -o $@ $<
ccan-noerr.o: $(CCANDIR)/ccan/noerr/noerr.c
Expand Down
1 change: 1 addition & 0 deletions ccan/ccan/daemonize/LICENSE
54 changes: 54 additions & 0 deletions ccan/ccan/daemonize/_info
Original file line number Diff line number Diff line change
@@ -0,0 +1,54 @@
#include "config.h"
#include <stdio.h>
#include <string.h>

/**
* daemonize - routine to turn a process into a well-behaved daemon.
*
* Daemons should detach themselves thoroughly from the process which launched
* them, and not prevent any filesystems from being unmounted. daemonize()
* helps with the process.
*
* Example:
* #include <ccan/daemonize/daemonize.h>
* #include <ccan/str/str.h>
* #include <err.h>
* #include <unistd.h>
* #include <stdlib.h>
*
* static void usage(const char *name)
* {
* errx(1, "Usage: %s [--daemonize]\n", name);
* }
*
* // Wait for a minute, possibly as a daemon.
* int main(int argc, char *argv[])
* {
* if (argc != 1) {
* if (argc == 2 && streq(argv[1], "--daemonize")) {
* if (!daemonize())
* err(1, "Failed to become daemon");
* } else
* usage(argv[1]);
* }
* sleep(60);
* exit(0);
* }
*
* License: BSD-MIT
*/
int main(int argc, char *argv[])
{
if (argc != 2)
return 1;

if (strcmp(argv[1], "depends") == 0) {
return 0;
}

if (strcmp(argv[1], "libs") == 0) {
return 0;
}

return 1;
}
45 changes: 45 additions & 0 deletions ccan/ccan/daemonize/daemonize.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
/* Licensed under BSD-MIT - see LICENSE file for details */
#include <ccan/daemonize/daemonize.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

/* This code is based on Stevens Advanced Programming in the UNIX
* Environment. */
bool daemonize(void)
{
pid_t pid;

/* Separate from our parent via fork, so init inherits us. */
if ((pid = fork()) < 0)
return false;
/* use _exit() to avoid triggering atexit() processing */
if (pid != 0)
_exit(0);

/* Don't hold files open. */
close(STDIN_FILENO);
close(STDOUT_FILENO);
close(STDERR_FILENO);

/* Many routines write to stderr; that can cause chaos if used
* for something else, so set it here. */
if (open("/dev/null", O_WRONLY) != 0)
return false;
if (dup2(0, STDERR_FILENO) != STDERR_FILENO)
return false;
close(0);

/* Session leader so ^C doesn't whack us. */
if (setsid() == (pid_t)-1)
return false;
/* Move off any mount points we might be in. */
if (chdir("/") != 0)
return false;

/* Discard our parent's old-fashioned umask prejudices. */
umask(0);
return true;
}
21 changes: 21 additions & 0 deletions ccan/ccan/daemonize/daemonize.h
Original file line number Diff line number Diff line change
@@ -0,0 +1,21 @@
/* Licensed under BSD-MIT - see LICENSE file for details */
#ifndef CCAN_DAEMONIZE_H
#define CCAN_DAEMONIZE_H
#include <stdbool.h>

/**
* daemonize - turn this process into a daemon.
*
* This routine forks us off to become a daemon. It returns false on failure
* (eg. fork(), chdir or open failed) and sets errno.
*
* Side effects for programmers to be aware of:
* - PID changes (our parent exits, we become child of init)
* - stdin and stdout file descriptors are closed
* - stderr is reopened to /dev/null so you don't reuse it
* - Current working directory changes to /
* - Umask is set to 0.
*/
bool daemonize(void);

#endif /* CCAN_DAEMONIZE_H */
76 changes: 76 additions & 0 deletions ccan/ccan/daemonize/test/run.c
Original file line number Diff line number Diff line change
@@ -0,0 +1,76 @@
#include <ccan/daemonize/daemonize.h>
#include <ccan/daemonize/daemonize.c>
#include <ccan/tap/tap.h>
#include <stdlib.h>
#include <unistd.h>
#include <err.h>
#include <errno.h>
#include <string.h>

struct child_data {
pid_t pid;
pid_t ppid;
bool in_root_dir;
int read_from_stdin, write_to_stdout, write_to_stderr;
};

int main(int argc, char *argv[])
{
int fds[2];
struct child_data daemonized;
pid_t pid;

plan_tests(5);

if (pipe(fds) != 0)
err(1, "Failed pipe");

/* Since daemonize forks and parent exits, we need to fork
* that parent. */
pid = fork();
if (pid == -1)
err(1, "Failed fork");

if (pid == 0) {
char buffer[2];
pid = getpid();
daemonize();
/* Keep valgrind happy about uninitialized bytes. */
memset(&daemonized, 0, sizeof(daemonized));
daemonized.pid = getpid();
daemonized.in_root_dir = (getcwd(buffer, 2) != NULL);
daemonized.read_from_stdin
= read(STDIN_FILENO, buffer, 1) == -1 ? errno : 0;
daemonized.write_to_stdout
= write(STDOUT_FILENO, buffer, 1) == -1 ? errno : 0;
if (write(STDERR_FILENO, buffer, 1) != 1) {
daemonized.write_to_stderr = errno;
if (daemonized.write_to_stderr == 0)
daemonized.write_to_stderr = -1;
} else
daemonized.write_to_stderr = 0;

/* Make sure parent exits. */
while (getppid() == pid)
sleep(1);
daemonized.ppid = getppid();
if (write(fds[1], &daemonized, sizeof(daemonized))
!= sizeof(daemonized))
exit(1);
exit(0);
}

if (read(fds[0], &daemonized, sizeof(daemonized)) != sizeof(daemonized))
err(1, "Failed read");

ok1(daemonized.pid != pid);
#if 0 /* Believe it or not, this fails under Ubuntu 13.10 (Upstart) */
ok1(daemonized.ppid == 1);
#endif
ok1(daemonized.in_root_dir);
ok1(daemonized.read_from_stdin == EBADF);
ok1(daemonized.write_to_stdout == EBADF);
ok1(daemonized.write_to_stderr == 0);

return exit_status();
}

0 comments on commit c5cc5c5

Please sign in to comment.