finit/src/tmpfiles.c

/* Limited tmpfiles.d implementation
 *
 * Copyright (c) 2023  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 <sys/sysmacros.h>
#include "finit.h"
#include "helpers.h"
#include "tmpfiles.h"
#include "util.h"

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 int do_delete(const char *fpath, const struct stat *sb, int tflag, struct FTW *ftw)
{
	if (ftw->level == 0)
		return 1;

	if (remove(fpath))
		warn("Failed removing condition %s", fpath);

	return 0;

}

static int rmrf(const char *path)
{
	if (!fisdir(path))
		return 0;

	nftw(path, do_delete, 20, FTW_DEPTH);
	if (remove(path) && errno != ENOENT)
		warn("Failed removing path %s", path);

	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);
}

/*
 * 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;
	}

	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 ");
	(void)age;		/* unused atm. */
	arg = strtok(NULL, "\n");

	strc = stat(path, &st);

	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 (!strc) {
			struct dirent **namelist;
			int num;

			if (!S_ISDIR(st.st_mode))
				break;
			num = scandir(path, &namelist, NULL, NULL);
			free(namelist);
			if (num >= 3)
				break; /* not empty */
		}
		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':
		mkparent(path, 0755);
		rc = mksubsys(path, mode ?: 0755, user, group);
		break;
	case 'e':
		if (glob(path, GLOB_NOESCAPE, NULL, &gl))
			break;

		for (size_t i = 0; i < gl.gl_pathc; i++)
			rc += mksubsys(gl.gl_pathv[i], mode ?: 0755, user, group);
		break;
	case 'f':
	case 'F':
		mkparent(path, 0755);
		if (type[1] == '+' || type[0] == 'F') {
			/* f+/F will create or truncate the file */
			if (!arg) {
				rc = create(path, mode ?: 0644, user, group);
				break;
			}
			fp = fopen(path, "w+");
		} else {
			/* f will create the file if it doesn't exist */
			if (strc)
				fp = fopen(path, "w");
		}

		if (fp) {
			write_arg(fp, arg);
			rc = fclose(fp);
		}
		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;
			rmrf(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':
		rc = glob_do(path, erase);
		if (rc && errno == ENOENT)
			rc = 0;
		break;
	case 'R':
		rc = glob_do(path, rmrf);
		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 '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++) {
			snprintf(buf, sizeof(buf), "restorecon %s %s", opts, gl.gl_pathv[i]);
			run(buf, "restorecon");
		}
		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);
}

/*
 * 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.
 */
void tmpfilesd(void)
{
	/* 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;
		FILE *fp;

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

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

		fp = fopen(fn, "r");
		if (!fp)
			continue;

//		info("Parsing %s ...", fn);
		while (!feof(fp)) {
			char *line;

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

			tmpfiles(line);
		}

		fclose(fp);
	}

	globfree(&gl);
}

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