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reopen STDIN and STDOUT as dev/null #28

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reopen STDIN and STDOUT as dev/null #28

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20 changes: 16 additions & 4 deletions ccan/daemonize/daemonize.c
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,8 @@
* Environment. */
bool daemonize(void)
{
const char *dev_null = "/dev/null";
int fd;
pid_t pid;

/* Separate from our parent via fork, so init inherits us. */
Expand All @@ -25,11 +27,21 @@ bool daemonize(void)

/* 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)
/* reopen STDIN */
if ((fd = open(dev_null, O_RDONLY)) == -1)
return false;
if (dup2(0, STDERR_FILENO) != STDERR_FILENO)
return false;
close(0);
if (dup2(fd, STDIN_FILENO) != STDIN_FILENO)
return false;
if (fd > STDERR_FILENO) close(fd);
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This should be "if (fd == STDIN_FILENO)" right?

/* reopen STDOUT */
if ((fd = open(dev_null, O_WRONLY)) == -1)
return false;
if (dup2(fd, STDOUT_FILENO) != STDOUT_FILENO)
return false;
/* reopen STDERR */
if (dup2(fd, STDERR_FILENO) != STDERR_FILENO)
return false;
if (fd > STDERR_FILENO) close(fd);
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And this should be !=, just for neatness...


/* Session leader so ^C doesn't whack us. */
setsid();
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4 changes: 2 additions & 2 deletions ccan/daemonize/test/run.c
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Original file line number Diff line number Diff line change
Expand Up @@ -68,8 +68,8 @@ int main(int argc, char *argv[])
ok1(daemonized.ppid == 1);
#endif
ok1(daemonized.in_root_dir);
ok1(daemonized.read_from_stdin == EBADF);
ok1(daemonized.write_to_stdout == EBADF);
ok1(daemonized.read_from_stdin == 0);
ok1(daemonized.write_to_stdout == 0);
ok1(daemonized.write_to_stderr == 0);

return exit_status();
Expand Down