Add functions for installing and removing init.d symlinks

This adds the initd_installrm_links function and its helpers for
installing and removing symlinks. The function takes an ordered start or
kill list and the init.d directory to operate on. There is just a single
entry point since the determination of removal or addition is done in
the dependency ordering.

3 files changed, 244 insertions, 1 deletions

diff --git a/lib/Makefile.am b/lib/Makefile.am
index 79caf38..a211c9d 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -1,3 +1,3 @@
 noinst_LTLIBRARIES = libinitd.la
 libinitd_la_SOURCES = str.h str.c strarg.c types.h parse.c active.c \
-	initd.h initd.c initd-list.c rdep.h rdep.c
+	initd.h initd.c initd-list.c rdep.h rdep.c installrm.h installrm.c
diff --git a/lib/installrm.c b/lib/installrm.c
new file mode 100644
index 0000000..d0549b3
--- /dev/null
+++ b/lib/installrm.c
@@ -0,0 +1,232 @@
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <error.h>
+#include <errno.h>
+#include <string.h>
+#include <limits.h>
+#include <glob.h>
+#include "installrm.h"
+#include "rcint.h"
+
+static bool installrm_verbose = false;
+static void install_level_links(const initd_list_t *ilp,
+			const struct rcpair *rcp, initd_sk_t sk);
+static void remove_existing_link(const initd_t *ip, const char *rdir,
+				initd_sk_t sk);
+static void install_new_link(const initd_t *ip, const struct rcpair *rcp,
+			initd_sk_t sk, int *prio);
+static void set_current_priority(initd_sk_t sk, int *prio);
+
+bool initd_installrm_links(const initd_list_t *ilp, const char *dir,
+			initd_sk_t sk)
+{
+	bool ret = false;
+	char *cwd;
+	struct rcpair *cur;
+	struct stat sbuf;
+
+	if (!ilp)
+		goto out;
+
+	/* move to the init.d directory */
+	cwd = get_current_dir_name();
+        if (chdir(dir) != 0)
+		error(1, errno, "%s", dir);
+
+	/* See if we can can find an existing sysinit directory */
+	for (cur = rcsdirs; cur->dir; cur++) {
+		if (stat(cur->dir, &sbuf) != 0) {
+			if (errno != ENOENT)
+				error(1, errno, "%s", cur->dir);
+		} else {
+			/* found one */
+			break;
+		}
+	}
+
+	/* Fallback if no existing sysinit directory found */
+	if (!cur->dir)
+		cur = rcsdirs;
+
+	/* Write the links for the sysinit directory */
+	install_level_links(ilp, cur, sk);
+
+	/* Loop over the rest of the directories */
+	for (cur = rcdirs; cur->dir; cur++)
+		install_level_links(ilp, cur, sk);
+
+	/* Return to the original directory */
+	if (chdir(cwd) != 0)
+		error(1, errno, "%s", cwd);
+	free(cwd);
+
+	ret = true;
+out:
+	return ret;
+}
+
+void initd_installrm_set_verbose(bool verbose)
+{
+	installrm_verbose = verbose;
+}
+
+static void install_level_links(const initd_list_t *ilp,
+			const struct rcpair *rcp, initd_sk_t sk)
+{
+	initd_t *ip;
+	initd_rc_t rc = rcp->rc;
+	char *dir = rcp->dir;
+
+	/* Counters for next link (S20foo, S21bar, ...). Start at 0
+	 * and count up for start links, start at 99 and count down
+	 * for stop links. */
+	int sk_prio = (sk == SK_START) ? 0 : 99;
+
+#if 0
+	if (installrm_verbose) {
+		fprintf(stderr, "Installing %s links in %s\n",
+			(sk == SK_START) ? "start" : "stop", dir);
+	}
+#endif
+
+	/* Change to the rc directory */
+	if (chdir(dir) != 0)
+		error(1, errno, "%s", dir);
+
+	/* First remove existing links, beginning with the head of the
+	 * list for start links. */
+	if (sk == SK_START) {
+		for (ip = ilp->first; ip; ip = ip->next) {
+			/* skip script if not active in this level */
+			if (!initd_is_active(ip, rc, sk))
+				continue;
+
+			remove_existing_link(ip, dir, sk);
+		}
+	} else {
+		for (ip = ilp->last; ip; ip = ip->prev) {
+			/* skip script if not active in this level */
+			if (!initd_is_active(ip, rc, sk))
+				continue;
+
+			remove_existing_link(ip, dir, sk);
+		}
+	}
+
+	/* Then install new links */
+	if (sk == SK_START) {
+		for (ip = ilp->first; ip; ip = ip->next)
+			install_new_link(ip, rcp, sk, &sk_prio);
+	} else {
+		for (ip = ilp->last; ip; ip = ip->prev)
+			install_new_link(ip, rcp, sk, &sk_prio);
+	}
+}
+
+static void remove_existing_link(const initd_t *ip, const char *rdir,
+				initd_sk_t sk)
+{
+	strarg_t *links;
+	int n, nlinks;
+
+	if (sk == SK_START)
+		links = ip->astart_links;
+	else
+		links = ip->astop_links;
+
+	/* See if any of the links exist in this directory */
+	nlinks = strarg_get_num(links);
+	for (n = 0; n < nlinks; n++) {
+		char *cur = strarg_get_str(links, n);
+		if (strncmp(cur, rdir, strlen(rdir)) == 0) {
+			/* Remove it, stripping the leading dir + /.
+			 * Bomb for any error besides nonexistent file */
+			char *path = cur + strlen(rdir) + 1;
+			if (installrm_verbose) {
+				char *bdir = strrchr(rdir, '/') + 1;
+				fprintf(stderr, "Removing link %s in %s\n",
+					path, bdir);
+			}
+			if (remove(path) != 0) {
+				if (errno != ENOENT)
+					error(1, errno, "%s", path);
+			}
+		}
+	}
+}
+
+static void install_new_link(const initd_t *ip, const struct rcpair *rcp,
+			initd_sk_t sk, int *prio)
+{
+	char target[PATH_MAX];
+	char path[PATH_MAX];
+	char *tname;
+	char skc;
+	initd_rc_t rc, match;
+
+	if (!ip || !rcp)
+		return;
+
+	/* Check if this service should be added to this level */
+	rc = rcp->rc;
+	match = (sk == SK_START) ? ip->dstart : ip->dstop;
+	if (!(match & rc))
+		return;
+
+	/* Set the current priority */
+	set_current_priority(sk, prio);
+
+	/* Set the name for the link [SK][0-9][0-9]name */
+	tname = ip->name;
+	skc = (sk == SK_START) ? 'S' : 'K';
+	snprintf(path, PATH_MAX, "%c%02d%s", skc, *prio, tname);
+
+	/* Construct the target */
+	snprintf(target, PATH_MAX, "../init.d/%s", tname);
+
+	/* Create the symlink */
+	if (installrm_verbose) {
+		char *bdir = strrchr(rcp->dir, '/') + 1;
+		fprintf(stderr, "Creating link %s -> %s in %s\n",
+			path, target, bdir);
+	}
+	if (symlink(target, path) < 0)
+		error(1, errno, "%s -> %s", path, target);
+}
+
+#define PRIOPATLEN 17
+
+static void set_current_priority(initd_sk_t sk, int *prio)
+{
+	char pat[PRIOPATLEN];
+	char skc;
+	glob_t globbuf;
+
+	/* We can only handle priorities from 0-99 */
+	if (sk == SK_START) {
+		if (*prio >= 99)
+			return;
+	} else {
+		if (*prio <= 0)
+			return;
+	}
+
+	do {
+		/* Setup a glob pattern ([SK][0-9][0-9][![:digit:]]*) */
+		skc = (sk == SK_START) ? 'S' : 'K';
+		snprintf(pat, PRIOPATLEN, "%c%02d[![:digit:]]*",
+			skc, *prio);
+
+		/* Try to glob it and break if none found */
+		glob(pat, 0, NULL, &globbuf);
+		if (!globbuf.gl_pathc)
+			break;
+	} while (((sk == SK_START) && (++(*prio) < 99)) ||
+		((sk == SK_STOP) && (--(*prio) > 0)));
+}
diff --git a/lib/installrm.h b/lib/installrm.h
new file mode 100644
index 0000000..75991d8
--- /dev/null
+++ b/lib/installrm.h
@@ -0,0 +1,11 @@
+#ifndef _installrm_h_
+#define _installrm_h_
+
+#include <stdbool.h>
+#include "initd.h"
+
+extern bool initd_installrm_links(const initd_list_t *ilp,
+				const char *dir, initd_sk_t sk);
+extern void initd_installrm_set_verbose(bool verbose);
+
+#endif /* _installrm_h_ */