xref: /aosp_15_r20/external/selinux/restorecond/watch.c (revision 2d543d20722ada2425b5bdab9d0d1d29470e7bba)

#define _GNU_SOURCE
#include <sys/inotify.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include <sys/types.h>
#include <syslog.h>
#include "restore.h"
#include <glob.h>
#include <libgen.h>
#include <sys/stat.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
#include <selinux/selinux.h>
#include "restorecond.h"
#include "stringslist.h"
#include "utmpwatcher.h"

#ifndef GLOB_TILDE
#define GLOB_TILDE 0
#endif

#ifndef GLOB_BRACE
#define GLOB_BRACE 0
#endif

/* size of the event structure, not counting name */
#define EVENT_SIZE  (sizeof (struct inotify_event))
/* reasonable guess as to size of 1024 events */
#define BUF_LEN        (1024 * (EVENT_SIZE + 16))

struct watchList {
	struct watchList *next;
	int wd;
	char *dir;
	struct stringsList *files;
};
struct watchList *firstDir = NULL;

int watch_list_isempty(void) {
	return firstDir == NULL;
}

void watch_list_add(int fd, const char *path)
{
	struct watchList *ptr = NULL;
	size_t i = 0;
	struct watchList *prev = NULL;
	glob_t globbuf;
	char *x = strdup(path);
	if (!x) exitApp("Out of Memory");
	char *file = basename(x);
	char *dir = dirname(x);
	ptr = firstDir;
	int len;

	globbuf.gl_offs = 1;
	if (glob(path,
		 GLOB_TILDE | GLOB_PERIOD,
		 NULL,
		 &globbuf) >= 0) {
		for (i = 0; i < globbuf.gl_pathc; i++) {
			len = strlen(globbuf.gl_pathv[i]) - 2;
			if (len > 0 &&
			    strcmp(&globbuf.gl_pathv[i][len--], "/.") == 0)
				continue;
			if (len > 0 &&
			    strcmp(&globbuf.gl_pathv[i][len], "/..") == 0)
				continue;
			selinux_restorecon(globbuf.gl_pathv[i],
					   r_opts.restorecon_flags);
		}
		globfree(&globbuf);
	}

	while (ptr != NULL) {
		if (strcmp(dir, ptr->dir) == 0) {
			strings_list_add(&ptr->files, file);
			goto end;
		}
		prev = ptr;
		ptr = ptr->next;
	}
	ptr = calloc(1, sizeof(struct watchList));

	if (!ptr) exitApp("Out of Memory");

	ptr->wd = inotify_add_watch(fd, dir, IN_CREATE | IN_MOVED_TO);
	if (ptr->wd == -1) {
		free(ptr);
		if (! run_as_user)
			syslog(LOG_ERR, "Unable to watch (%s) %s\n",
			       path, strerror(errno));
		goto end;
	}

	ptr->dir = strdup(dir);
	if (!ptr->dir)
		exitApp("Out of Memory");

	strings_list_add(&ptr->files, file);
	if (prev)
		prev->next = ptr;
	else
		firstDir = ptr;

	if (debug_mode)
		printf("%d: Dir=%s, File=%s\n", ptr->wd, ptr->dir, file);

end:
	free(x);
	return;
}

/*
   A file was in a direcroty has been created. This function checks to
   see if it is one that we are watching.
*/

int watch_list_find(int wd, const char *file)
{
	struct watchList *ptr = NULL;

	ptr = firstDir;

	if (debug_mode)
		printf("%d: File=%s\n", wd, file);
	while (ptr != NULL) {
		if (ptr->wd == wd) {
			int exact=0;
			if (strings_list_find(ptr->files, file, &exact) == 0) {
				char *path = NULL;
				if (asprintf(&path, "%s/%s", ptr->dir, file) <
				    0)
					exitApp("Error allocating memory.");

				selinux_restorecon(path,
						   r_opts.restorecon_flags);
				free(path);
				return 0;
			}
			if (debug_mode)
				strings_list_print(ptr->files);

			/* Not found in this directory */
			return -1;
		}
		ptr = ptr->next;
	}
	/* Did not find a directory */
	return -1;
}

void watch_list_free(int fd)
{
	struct watchList *ptr = NULL;
	struct watchList *prev = NULL;
	ptr = firstDir;

	while (ptr != NULL) {
		inotify_rm_watch(fd, ptr->wd);
		strings_list_free(ptr->files);
		free(ptr->dir);
		prev = ptr;
		ptr = ptr->next;
		free(prev);
	}
	firstDir = NULL;
}

/*
   Inotify watch loop
*/
int watch(int fd, const char *watch_file)
{
	char buf[BUF_LEN];
	int len, i = 0;
	if (firstDir == NULL) return 0;

	len = read(fd, buf, BUF_LEN);
	if (len < 0) {
		if (terminate == 0) {
			syslog(LOG_ERR, "Read error (%s)", strerror(errno));
			return 0;
		}
		syslog(LOG_INFO, "terminated");
		return -1;
	} else if (!len)
		/* BUF_LEN too small? */
		return -1;
	while (i < len) {
		struct inotify_event *event;
		event = (struct inotify_event *)&buf[i];
		if (debug_mode)
			printf("wd=%d mask=%u cookie=%u len=%u\n",
			       event->wd, event->mask,
			       event->cookie, event->len);
		if (event->mask & ~IN_IGNORED) {
			if (event->wd == master_wd)
				read_config(fd, watch_file);
			else {
				switch (utmpwatcher_handle(fd, event->wd)) {
				case -1:	/* Message was not for utmpwatcher */
					if (event->len)
						watch_list_find(event->wd, event->name);
					break;
				case 1:	/* utmp has changed need to reload */
					read_config(fd, watch_file);
					break;

				default:	/* No users logged in or out */
					break;
				}
			}
		}

		i += EVENT_SIZE + event->len;
	}
	return 0;
}

static void process_config(int fd, FILE * cfg)
{
	char *line_buf = NULL;
	size_t len = 0;

	while (getline(&line_buf, &len, cfg) > 0) {
		char *buffer = line_buf;
		while (isspace(*buffer))
			buffer++;
		if (buffer[0] == '#')
			continue;
		int l = strlen(buffer) - 1;
		if (l <= 0)
			continue;
		buffer[l] = 0;
		if (buffer[0] == '~') {
			if (run_as_user) {
				char *ptr=NULL;
				if (asprintf(&ptr, "%s%s", homedir, &buffer[1]) < 0)
					exitApp("Error allocating memory.");

				watch_list_add(fd, ptr);
				free(ptr);
			} else {
				utmpwatcher_add(fd, &buffer[1]);
			}
		} else {
			watch_list_add(fd, buffer);
		}
	}
	free(line_buf);
}

/*
   Read config file ignoring Comment lines
   Files specified one per line.  Files with "~" will be expanded to the logged in users
   homedirs.
*/

void read_config(int fd, const char *watch_file_path)
{

	FILE *cfg = NULL;
	if (debug_mode)
		printf("Read Config\n");

	watch_list_free(fd);

	cfg = fopen(watch_file_path, "r");
	if (!cfg){
		perror(watch_file_path);
		exitApp("Error reading config file");
	}
	process_config(fd, cfg);
	fclose(cfg);

	inotify_rm_watch(fd, master_wd);
	master_wd =
	    inotify_add_watch(fd, watch_file_path, IN_MOVED_FROM | IN_MODIFY);
	if (master_wd == -1)
		exitApp("Error watching config file.");
}