finit/src/tmpfiles.c

/* Limited tmpfiles.d implementation
 *
 * Copyright (c) 2025  Joachim Wiberg <troglobit@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

#include "config.h"		/* Generated by configure script */

#include <dirent.h>
#include <ftw.h>
#include <getopt.h>
#include <glob.h>
#include <libgen.h>
#include <grp.h>
#include <pwd.h>
#include <sys/sysmacros.h>

#include <stdlib.h>
#include <string.h>
#include <time.h>
#ifdef _LIBITE_LITE
# include <libite/lite.h>
#else
# include <lite/lite.h>
#endif

#include "log.h"
#include "util.h"

int debug;

int create_flag = 0;
int clean_flag = 0;
int remove_flag = 0;

#define MAX_EXCLUDES 32
static const char *exclude_prefixes[MAX_EXCLUDES];
static int num_excludes;

static void add_exclude_prefix(const char *prefix)
{
	if (num_excludes < MAX_EXCLUDES)
		exclude_prefixes[num_excludes++] = prefix;
}

static int excluded(const char *path)
{
	for (int i = 0; i < num_excludes; i++) {
		if (!strncmp(path, exclude_prefixes[i], strlen(exclude_prefixes[i])))
			return 1;
	}

	return 0;
}

static int is_dir_empty(const char *path)
{
	struct dirent **namelist = NULL;
	int num;

	num = scandir(path, &namelist, NULL, NULL);
	if (num < 0)
		return 0;

	for (int i = 0; i < num; i++)
		free(namelist[i]);
	free(namelist);

	return num >= 3;
}

static int glob_do(const char *path, int (*cb)(const char *))
{
	int rc = 0;
	glob_t gl;

	rc = glob(path, GLOB_NOESCAPE, NULL, &gl);
	if (rc) {
		if (rc == GLOB_NOMATCH) {
			errno = ENOENT;
			return -1;
		}
		return 0;
	}

	for (size_t i = 0; i < gl.gl_pathc; i++)
		rc += cb(gl.gl_pathv[i]);

	return rc;
}

static int parse_mm(char *arg, int *major, int *minor)
{
	char *ptr;

	if (!arg) {
	inval:
		errno = EINVAL;
		return -1;
	}

	ptr = strchr(arg, ':');
	if (!ptr)
		goto inval;

	*ptr++ = 0;
	*major = atoi(arg);
	*minor = atoi(ptr);

	if (!*major || !*minor)
		return -1;

	return 0;
}

static void mkparent(char *path, mode_t mode)
{
	mkpath(dirname(strdupa(path)), mode);
}

static char *write_hex(FILE *fp, char *p)
{
	unsigned char val;
	char num[4], *ptr;
	int i, len = 0;

	for (i = 0; p[i] && len < 2; i++) {
		char c = p[i];

		if ((c >= '0' && c <= '7') ||
		    (c >= 'a' && c <= 'f') ||
		    (c >= 'A' && c <= 'F'))
			num[len++] = c;
		else
			break;
	}

	num[len] = 0;
	if (len == 0) {
		fputs("x", fp);
		return p;
	}

	errno = 0;
	val = strtoul(num, &ptr, 16);
	if (errno || ptr == num)
		goto end;

	fputc(val & 0xff, fp);
end:
	return &p[i];
}

static char *write_num(FILE *fp, char *p)
{
	unsigned char val;
	char num[4], *ptr;
	int i, len = 0;

	for (i = 0; p[i] && len < 3; i++) {
		char c = p[i];

		if (c >= '0' && c <= '7')
			num[len++] = c;
		else
			break;
	}

	num[len] = 0;
	if (len == 0)
		return p;

	errno = 0;
	val = strtoul(num, &ptr, 8);
	if (errno || ptr == num)
		goto end;

	fputc(val & 0xff, fp);
end:
	return &p[i];
}

static void write_arg(FILE *fp, char *arg)
{
	char *p;

	if (!arg)
		return;

	while (*arg && (p = strchr(arg, '\\'))) {
		fwrite(arg, sizeof(char), p - arg, fp);

		*p++ = 0;
		switch (*p) {
		case '\\':
			fputc('\\', fp);
			arg = p + 1;
			break;
		case '\'':
			fputc('\'', fp);
			arg = p + 1;
			break;
		case '"':
			fputc('"', fp);
			arg = p + 1;
			break;
		case 'a':
			fputc('\a', fp);
			arg = p + 1;
			break;
		case 'b':
			fputc('\b', fp);
			arg = p + 1;
			break;
		case 'e':
			fputc('\e', fp);
			arg = p + 1;
			break;
		case 'n':
			fputc('\n', fp);
			arg = p + 1;
			break;
		case 't':
			fputc('\t', fp);
			arg = p + 1;
			break;
		case 'x':
			arg = write_hex(fp, &p[1]);
			break;
		case '0' ... '7':
			arg = write_num(fp, p);
			break;
		default:
			fputc(*p, fp);
			arg = p + 1;
			break;
		}
	}
	fputs(arg, fp);
}

/**
 * Parse age string and return age in seconds.
 * Returns 0 on invalid/empty age ("-" or NULL).
 * Examples: "10d" = 864000, "1w" = 604800, "2h" = 7200
 */
static time_t parse_age(const char *age)
{
	time_t val;
	char *end;

	if (!age || !strcmp(age, "-") || !strcmp(age, "0"))
		return 0;

	errno = 0;
	val = strtoul(age, &end, 10);
	if (errno || end == age)
		return 0;

	switch (*end) {
	case 'w':
		val *= 7;
		/* fallthrough */
	case 'd':
		val *= 24;
		/* fallthrough */
	case 'h':
		val *= 60;
		/* fallthrough */
	case 'm':
		val *= 60;
		/* fallthrough */
	case 's':
	case '\0':
		break;
	default:
		return 0;	/* unknown suffix */
	}

	return val;
}

/**
 * Parse user string - supports both names and numeric UIDs.
 * Returns UID on success, -1 on failure.
 */
static int parse_uid(const char *user)
{
	long val;

	if (!user || !user[0])
		return 0;

	/* Check if it's a numeric UID */
	val = atonum(user);
	if (val >= 0)
		return val;

	/* Not numeric, look up by name */
	return getuser(user, NULL);
}

/**
 * Parse group string - supports both names and numeric GIDs.
 * Returns GID on success, -1 on failure.
 */
static int parse_gid(const char *group)
{
	long val;

	if (!group || !group[0])
		return 0;

	/* Check if it's a numeric GID */
	val = atonum(group);
	if (val >= 0)
		return val;

	/* Not numeric, look up by name */
	return getgroup(group);
}

/* Globals for do_clean() callback - nftw doesn't support user data */
static time_t clean_age;
static time_t clean_now;

static int do_clean(const char *fpath, const struct stat *sb, int tflag, struct FTW *ftw)
{
	int is_dir;

	/* Skip the root directory itself */
	if (ftw->level == 0)
		return 0;

	is_dir = (tflag == FTW_D || tflag == FTW_DP);

	/*
	 * Conservative cleanup matching systemd-tmpfiles behavior:
	 * - Files: keep if ANY of atime, ctime, mtime is recent
	 * - Directories: keep if ANY of atime, mtime is recent (ctime
	 *   excluded because cleanup itself updates directory ctime)
	 */
	if (clean_now - sb->st_mtime < clean_age)
		return 0;	/* mtime is too new, keep it */

	if (clean_now - sb->st_atime < clean_age)
		return 0;	/* atime is too new, keep it */

	if (!is_dir && clean_now - sb->st_ctime < clean_age)
		return 0;	/* ctime is too new, keep it (files only) */

	if (remove(fpath) && errno != ENOENT && errno != EBUSY)
		warn("Failed cleaning %s", fpath);

	return 0;
}

/*
 * The configuration format is one line per path, containing type, path,
 * mode, ownership, age, and argument fields. The lines are separated by
 * newlines, the fields by whitespace:
 *
 * #Type Path        Mode User Group Age Argument…
 * d     /run/user   0755 root root  10d -
 * L     /tmp/foobar -    -    -     -   /dev/null
 *
 * https://www.freedesktop.org/software/systemd/man/tmpfiles.d.html
 */
static void tmpfiles(char *line)
{
	char *type, *path, *token, *user, *group, *age, *arg;
	char *dst = NULL, *opts = "";
	struct stat st, ast;
	int major, minor;
	int strc, rc = 0;
	mode_t mode = 0;
	FILE *fp = NULL;
	char buf[1024];
	glob_t gl;

	type = strtok(line, "\t ");
	if (!type)
		return;

	path = strtok(NULL, "\t ");
	if (!path)
		return;
	if (strchr(path, '%')) {
		errx(1, "Path name specifiers unsupported, skipping.");
		return;
	}
	if (excluded(path))
		return;

	token = strtok(NULL, "\t ");
	if (token) {
		errno = 0;
		mode = strtoul(token, &arg, 8);
		if (errno || arg == token)
			mode = 0;
	}

	user = strtok(NULL, "\t ");
	if (!user || !strcmp(user, "-"))
		user = "root";
	group = strtok(NULL, "\t ");
	if (!group || !strcmp(group, "-"))
		group = "root";

	age = strtok(NULL, "\t ");
	arg = strtok(NULL, "\n");

	strc = stat(path, &st);

	// file and directory removal logic
	if (remove_flag) {
		switch (type[0]) {
		case 'b':
		case 'c':
		case 'C':
		case 'd':
			break;
		case 'D':
			rmcontents(path);
			break;
		case 'e':
		case 'f':
		case 'F':
		case 'l': /* Finit extension, like 'L' but only if target exists */
		case 'L':
		case 'p':
			break;
		case 'r':
			rc = glob_do(path, erase);
			if (rc && errno == ENOENT)
				rc = 0;
			break;
		case 'R':
			rc = glob_do(path, rmrf);
			break;
		case 'w':
			break;
		case 'X':
		case 'x':
			/* handled by clean_flag (--clean) */
			break;
		case 'Z':
		case 'z':
			break;
		default:
			errx(1, "Unsupported tmpfiles command '%s'", type);
			return;
		}
	}

	/* age-based cleanup logic */
	if (clean_flag) {
		time_t max_age = parse_age(age);

		/* Only process if age is specified */
		if (max_age > 0) {
			switch (type[0]) {
			case 'd':
			case 'D':
			case 'e':
				if (!fisdir(path))
					break;
				clean_age = max_age;
				clean_now = time(NULL);
				nftw(path, do_clean, 20, FTW_DEPTH | FTW_PHYS);
				break;
			case 'x':
			case 'X':
				/* exclusion patterns - not yet implemented */
				break;
			default:
				break;
			}
		}
	}

	// file & directory creation logic
	if (create_flag) {
		switch (type[0]) {
		case 'b':
			rc = parse_mm(arg, &major, &minor);
			if (rc)
				break;
			if (!strc) {
				if (type[1] != '+')
					break;
				erase(path);
			}
			mkparent(path, 0755);
			rc = blkdev(path, mode ?: 0644, major, minor);
			break;
		case 'c':
			rc = parse_mm(arg, &major, &minor);
			if (rc)
				break;
			if (!strc) {
				if (type[1] != '+')
					break;
				erase(path);
			}
			mkparent(path, 0755);
			rc = chardev(path, mode ?: 0644, major, minor);
			break;
		case 'C':
			if (!arg) {
				paste(buf, sizeof(buf), "/usr/share/factory", path);
				arg = buf;
			}
			if (fisdir(path) && !is_dir_empty(path))
				break;
			if (fisdir(arg) && !fisslashdir(arg)) {
				size_t len = strlen(arg) + 2;

				dst = malloc(len);
				if (!dst)
					break;
				snprintf(dst, len, "%s/", arg);
				arg = dst;
			}
			mkparent(path, 0755);
			rc = rsync(arg, path, LITE_FOPT_KEEP_MTIME, NULL);
			if (rc && errno == ENOENT)
				rc = 0;
			break;
		case 'd':
		case 'D': {
			int uid, gid;
			mode_t omask;

			mkparent(path, 0755);
			omask = umask(0);
			uid = parse_uid(user);
			if (uid >= 0) {
				gid = parse_gid(group);
				if (gid < 0)
					gid = 0;

				if (!mode)
					mode = 0755;
				rc = makedir(path, mode);
				if (!rc && dirperm(path, mode, uid, gid))
					warn("Failed setting mode/owner on %s", path);
			}
			umask(omask);
			break;
		}
		case 'e':
			if (glob(path, GLOB_NOESCAPE, NULL, &gl))
				break;

			for (size_t i = 0; i < gl.gl_pathc; i++) {
				char *p = gl.gl_pathv[i];
				int uid, gid;

				/* e only adjusts existing directories */
				if (!fisdir(p))
					continue;

				uid = parse_uid(user);
				gid = parse_gid(group);
				if (gid < 0)
					gid = 0;

				if (mode)
					chmod(p, mode);
				if (uid >= 0 && chown(p, uid, gid))
					warn("Failed chown(%s, %d, %d)", p, uid, gid);
			}
			break;
		case 'f':
		case 'F':
			mkparent(path, 0755);
			if (type[1] == '+' || type[0] == 'F') {
				/* f+/F will create or truncate the file */
				fp = fopen(path, "w+");
			} else {
				/* f will create the file if it doesn't exist */
				if (strc)
					fp = fopen(path, "w");
			}

			if (fp) {
				int uid, gid;

				write_arg(fp, arg);
				rc = fclose(fp);

				/* Apply mode and ownership */
				if (mode)
					chmod(path, mode);
				uid = parse_uid(user);
				gid = parse_gid(group);
				if (gid < 0)
					gid = 0;
				if (uid >= 0 && chown(path, uid, gid))
					warn("Failed chown(%s, %d, %d)", path, uid, gid);
			}
			break;
		case 'l': /* Finit extension, like 'L' but only if target exists */
			if (!arg) {
				paste(buf, sizeof(buf), "/usr/share/factory", path);
				if (stat(buf, &ast))
					break;
			} else if (arg[0] != '/') {
				char *tmp;

				tmp = dirname(strdupa(path));
				paste(buf, sizeof(buf), tmp, arg);
				dst = realpath(buf, NULL);
				if (!dst)
					break;
				if (stat(dst, &ast))
					break;
			} else {
				if (stat(arg, &ast))
					break;
			}
			/* fallthrough */
		case 'L':
			if (!strc) {
				if (type[1] != '+')
					break;
				if (fisdir(path))
					rmrf(path);
				else
					erase(path);
			}
			mkparent(path, 0755);
			if (!arg) {
				paste(buf, sizeof(buf), "/usr/share/factory", path);
				arg = buf;
			}
			rc = ln(arg, path);
			if (rc && errno == EEXIST)
				rc = 0;
			break;
		case 'p':
			if (!strc) {
				if (type[1] != '+')
					break;
				erase(path);
			}
			mkparent(path, 0755);
			rc = mkfifo(path, mode ?: 0644);
			break;
		case 'r':
		case 'R':
			break;
		case 'w':
			if (!arg)
				break;

			if (glob(path, GLOB_NOESCAPE, NULL, &gl))
				break;

			for (size_t i = 0; i < gl.gl_pathc; i++) {
				fp = fopen(gl.gl_pathv[i], type[1] == '+' ? "a" : "w");
				if (fp) {
					write_arg(fp, arg);
					rc = fclose(fp);
				}
			}
			break;
		case 'X':
		case 'x':
			/* handled by clean_flag (--clean) */
			break;
		case 'Z':
			opts = "-R";
			/* fallthrough */
		case 'z':
			if (!whichp("restorecon"))
				break;
			if (glob(path, GLOB_NOESCAPE, NULL, &gl))
				break;

			for (size_t i = 0; i < gl.gl_pathc; i++)
				systemf("restorecon %s %s", opts, gl.gl_pathv[i]);
			break;
		default:
			errx(1, "Unsupported tmpfiles command '%s'", type);
			return;
		}
	}

	if (dst)
		free(dst);

	if (rc)
		warn("Failed %s operation on path %s", type, path);
}

static void process_file(const char *fn)
{
	FILE *fp;

	fp = fopen(fn, "r");
	if (!fp) {
		warn("Failed to open %s", fn);
		return;
	}

	while (!feof(fp)) {
		char *line;

		line = fparseln(fp, NULL, NULL, NULL, FPARSELN_UNESCCOMM);
		if (!line)
			continue;

		tmpfiles(line);
		free(line);
	}

	fclose(fp);
}

static int usage(int rc)
{
	fprintf(stderr,
		"Usage: tmpfiles [OPTIONS] [CONFIGFILE...]\n"
		"\n"
		"Options:\n"
		"  -C, --clean               Clean files and directories based on age\n"
		"  -c, --create              Create files and directories\n"
		"  -d, --debug               Show developer debug messages\n"
		"  -E                        Exclude /dev, /proc, /run, and /sys\n"
		"      --exclude-prefix=PFX  Ignore rules for paths starting with PFX\n"
		"  -r, --remove              Remove files and directories marked for removal\n"
		"  -h, --help                This help text\n"
		"\n"
		"If no CONFIGFILE is specified, all *.conf files in the standard\n"
		"tmpfiles.d directories are processed.\n"
		"\n");

	return rc;
}

enum {
	OPT_EXCLUDE_PREFIX = 256,
};

int main(int argc, char *argv[])
{
	struct option long_options[] = {
		{ "clean",          0, NULL, 'C' },
		{ "create",         0, NULL, 'c' },
		{ "debug",          0, NULL, 'd' },
		{ "exclude-prefix", 1, NULL, OPT_EXCLUDE_PREFIX },
		{ "remove",         0, NULL, 'r' },
		{ "help",           0, NULL, 'h' },
		{ NULL, 0, NULL, 0 }
	};

	int c;

	while ((c = getopt_long(argc, argv, "CcdrEh?", long_options, NULL)) != EOF) {
		switch(c) {
		case 'C':
			clean_flag = 1;
			break;

		case 'c':
			create_flag = 1;
			break;

		case 'd':
			debug = 1;
			break;

		case 'E':
			add_exclude_prefix("/dev");
			add_exclude_prefix("/proc");
			add_exclude_prefix("/run");
			add_exclude_prefix("/sys");
			break;

		case OPT_EXCLUDE_PREFIX:
			add_exclude_prefix(optarg);
			break;

		case 'r':
			remove_flag = 1;
			break;

		case 'h':
		case '?':
			return usage(0);

		default:
			return usage(1);
		}
	}

	if (create_flag + clean_flag + remove_flag == 0) {
		fprintf(stderr, "You need to specify at least one of --clean, --create, or --remove.\n");
		return 1;
	}

	/* If config files specified on command line, process only those */
	if (optind < argc) {
		for (int i = optind; i < argc; i++)
			process_file(argv[i]);
		return 0;
	}

	/*
	 * No config files specified, process standard tmpfiles.d directories.
	 *
	 * Only the three last tmpfiles.d/ directories are defined in
	 * tmpfiles.d(5) as system search paths.  Finit adds two more
	 * before that to have Finit specific ones sorted first, and
	 * a configure prefix specific one after that for user needs.
	 */

	/* in priority order */
	char *dir[] = {
		FINIT_TMPFILES "/*.conf",
		TMPFILES_PATH_ "/*.conf",
		"/usr/lib/tmpfiles.d/*.conf",
		"/run/tmpfiles.d/*.conf",
		"/etc/tmpfiles.d/*.conf", /* local admin overrides */
	};
	int flags = GLOB_NOESCAPE;
	glob_t gl;
	size_t i;

	for (i = 0; i < NELEMS(dir); i++) {
		glob(dir[i], flags, NULL, &gl);
		flags |= GLOB_APPEND;
	}

	for (i = 0; i < gl.gl_pathc; i++) {
		char *fn = gl.gl_pathv[i];
		size_t j;

		/* check for overrides */
		for (j = i + 1; j < gl.gl_pathc; j++) {
			if (strcmp(basenm(fn), basenm(gl.gl_pathv[j])))
				continue;
			fn = NULL;
			break;
		}

		if (!fn)
			continue; /* skip, override exists */

		process_file(fn);
	}

	globfree(&gl);

	return 0;
}

/**
 * Local Variables:
 *  indent-tabs-mode: t
 *  c-file-style: "linux"
 * End:
 */