pidfiles again

[Denis Vlasenko]

Hello Stephane,

Thanks for your efforts to improve busybox.

On Monday 26 March 2007 23:26, Stephane Billiart wrote:
> With the patch, people who don't need pidfiles at all, because they're
> using runsv or simply don't care can get a smaller busybox with no pidfile
> at all and those, like me, who want them can enable them so that crond
> and syslogd behave like the traditional versions.

+int writepidfile(const char *path)
+{
+       FILE *pidf;
+
+       pidf = fopen_or_warn(path, "w");
+       if (pidf) {
+               fprintf(pidf, "%u\n", getpid());
+               fclose(pidf);
+               return 0;
+       }
+       return 1;
+}

Can we avoid using stdio.h here? Pseudocode:
open();
full_write(itoa(getpid()) + "\n");
close();

But minor issues aside, let's take a look at this:

+#define removepidfile(f) remove_file(f, FILEUTILS_FORCE)

Please take a good look into remove_file() function body:

int remove_file(const char *path, int flags)
{
...
        if (S_ISDIR(path_stat.st_mode)) {
...
                if ((!(flags & FILEUTILS_FORCE) && access(path, W_OK) < 0 &&
                                        isatty(0)) ||
                                (flags & FILEUTILS_INTERACTIVE)) {
                        fprintf(stderr, "%s: descend into directory '%s'? ", applet_name,
                                        path);
                        if (!bb_ask_confirmation())
                                return 0;

What, syslogd will start talking to user? Daemonized syslogd???
[Well, not really, we try hard to prevent that by closing stdio,
but still... can we just unlink the pidfile?]

> The patch does not address udhcpc/udhcpd which still have a distinct
> pidfile writing code.

I recently touched it a bit, while trying to improve chances that
udhcp will work on NOMMU.

> Could this be merged in the trunk?

I would prefer another iteration. Start from attached patch...
--
vda

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