X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=librunas%2Frunas.c;fp=librunas%2Frunas.c;h=24a772ccf2f9c253d3d0a0635783c5ab947f6b89;hp=0000000000000000000000000000000000000000;hb=60b6c79cedc1023732ff0935aa85b5d0d1c2bcbf;hpb=67f747d8095da3f240f71e33c4a1eb0f84aa5e41

diff --git a/librunas/runas.c b/librunas/runas.c
new file mode 100644
index 000000000..24a772ccf
--- /dev/null
+++ b/librunas/runas.c
@@ -0,0 +1,226 @@
+/*
+ * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca>
+ *                      Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; only version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include <lttngerr.h>
+
+struct mkdir_data {
+	const char *path;
+	mode_t mode;
+};
+
+struct open_data {
+	const char *path;
+	int flags;
+	mode_t mode;
+};
+
+/*
+ * Create recursively directory using the FULL path.
+ */
+static
+int _mkdir_recursive(void *_data)
+{
+	struct mkdir_data *data = _data;
+	const char *path;
+	char *p, tmp[PATH_MAX];
+	struct stat statbuf;
+	mode_t mode;
+	size_t len;
+	int ret;
+
+	path = data->path;
+	mode = data->mode;
+
+	ret = snprintf(tmp, sizeof(tmp), "%s", path);
+	if (ret < 0) {
+		PERROR("snprintf mkdir");
+		goto error;
+	}
+
+	len = ret;
+	if (tmp[len - 1] == '/') {
+		tmp[len - 1] = 0;
+	}
+
+	for (p = tmp + 1; *p; p++) {
+		if (*p == '/') {
+			*p = 0;
+			ret = stat(tmp, &statbuf);
+			if (ret < 0) {
+				ret = mkdir(tmp, mode);
+				if (ret < 0) {
+					if (!(errno == EEXIST)) {
+						PERROR("mkdir recursive");
+						ret = -errno;
+						goto error;
+					}
+				}
+			}
+			*p = '/';
+		}
+	}
+
+	ret = mkdir(tmp, mode);
+	if (ret < 0) {
+		if (!(errno == EEXIST)) {
+			PERROR("mkdir recursive last piece");
+			ret = -errno;
+		} else {
+			ret = 0;
+		}
+	}
+
+error:
+	return ret;
+}
+
+static
+int _mkdir(void *_data)
+{
+	struct mkdir_data *data = _data;
+	return mkdir(data->path, data->mode);
+}
+
+static
+int _open(void *_data)
+{
+	struct open_data *data = _data;
+	return open(data->path, data->flags, data->mode);
+}
+
+static
+int run_as(int (*cmd)(void *data), void *data, uid_t uid, gid_t gid)
+{
+	int ret = 0;
+	pid_t pid;
+
+	/*
+	 * If we are non-root, we can only deal with our own uid.
+	 */
+	if (geteuid() != 0) {
+		if (uid != geteuid()) {
+			ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)",
+				uid, geteuid());
+			return -EPERM;
+		}
+		return (*cmd)(data);
+	}
+
+	pid = fork();
+	if (pid > 0) {
+		int status;
+ 
+		/*
+		 * Parent: wait for child to return, in which case the
+		 * shared memory map will have been created.
+		 */
+		pid = wait(&status);
+		if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
+			ret = -1;
+			goto end;
+		}
+		goto end;
+	} else if (pid == 0) {
+		/* Child */
+		setegid(gid);
+		if (ret < 0) {
+			perror("setegid");
+			exit(EXIT_FAILURE);
+		}
+		ret = seteuid(uid);
+		if (ret < 0) {
+			perror("seteuid");
+			exit(EXIT_FAILURE);
+		}
+		umask(0);
+		ret = (*cmd)(data);
+		if (!ret)
+			exit(EXIT_SUCCESS);
+		else
+			exit(EXIT_FAILURE);
+	} else {
+		return -1;
+	}
+end:
+	return ret;
+}
+
+int mkdir_recursive_run_as(const char *path, mode_t mode, uid_t uid, gid_t gid)
+{
+	struct mkdir_data data;
+
+	DBG3("mkdir() recursive %s with mode %d for uid %d and gid %d",
+			path, mode, uid, gid);
+	data.path = path;
+	data.mode = mode;
+	return run_as(_mkdir_recursive, &data, uid, gid);
+}
+
+int mkdir_run_as(const char *path, mode_t mode, uid_t uid, gid_t gid)
+{
+	struct mkdir_data data;
+
+	DBG3("mkdir() %s with mode %d for uid %d and gid %d",
+			path, mode, uid, gid);
+	data.path = path;
+	data.mode = mode;
+	return run_as(_mkdir, &data, uid, gid);
+}
+
+/*
+ * Note: open_run_as is currently not working. We'd need to pass the fd
+ * opened in the child to the parent.
+ */
+int open_run_as(const char *path, int flags, mode_t mode, uid_t uid, gid_t gid)
+{
+	//struct open_data data;
+	int fd, ret;
+
+	DBG3("open() %s with flags %d mode %d for uid %d and gid %d",
+			path, flags, mode, uid, gid);
+	fd = open(path, flags, mode);
+	if (fd < 0) {
+		perror("open");
+		return fd;
+	}
+	ret = fchown(fd, uid, gid);
+	if (ret < 0) {
+		perror("fchown");
+		close(fd);
+		return ret;
+	}
+	return fd;
+#if 0
+	data.path = path;
+	data.flags = flags;
+	data.mode = mode;
+	return run_as(_open, &data, uid, gid);
+#endif
+}