X-Git-Url: http://git.efficios.com/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Futils.c;h=a092d940f422979b724fa5a61a72365c54b83ad7;hp=bf93386c46147eca75e33c59a13b9f8214f49ba4;hb=81684730b3134c61ca310bf26733c01d783103d7;hpb=fbb9748b6dc509542c4a82960da36d7b03a3a66b

diff --git a/src/common/utils.c b/src/common/utils.c
index bf93386c4..a092d940f 100644
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -17,25 +17,31 @@
  * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#define _GNU_SOURCE
+#define _LGPL_SOURCE
 #include <assert.h>
 #include <ctype.h>
 #include <fcntl.h>
 #include <limits.h>
 #include <stdlib.h>
-#include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <inttypes.h>
 #include <grp.h>
 #include <pwd.h>
+#include <sys/file.h>
+#include <unistd.h>
 
 #include <common/common.h>
 #include <common/runas.h>
+#include <common/compat/getenv.h>
+#include <common/compat/string.h>
+#include <common/compat/dirent.h>
+#include <lttng/constant.h>
 
 #include "utils.h"
 #include "defaults.h"
+#include "time.h"
 
 /*
  * Return a partial realpath(3) of the path even if the full path does not
@@ -51,7 +57,7 @@
 LTTNG_HIDDEN
 char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 {
-	char *cut_path, *try_path = NULL, *try_path_prev = NULL;
+	char *cut_path = NULL, *try_path = NULL, *try_path_prev = NULL;
 	const char *next, *prev, *end;
 
 	/* Safety net */
@@ -78,6 +84,8 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 
 	/* Resolve the canonical path of the first part of the path */
 	while (try_path != NULL && next != end) {
+		char *try_path_buf = NULL;
+
 		/*
 		 * If there is not any '/' left, we want to try with
 		 * the full path
@@ -88,11 +96,22 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 		}
 
 		/* Cut the part we will be trying to resolve */
-		cut_path = strndup(path, next - path);
+		cut_path = lttng_strndup(path, next - path);
+		if (cut_path == NULL) {
+			PERROR("lttng_strndup");
+			goto error;
+		}
+
+		try_path_buf = zmalloc(LTTNG_PATH_MAX);
+		if (!try_path_buf) {
+			PERROR("zmalloc");
+			goto error;
+		}
 
 		/* Try to resolve this part */
-		try_path = realpath((char *)cut_path, NULL);
+		try_path = realpath((char *) cut_path, try_path_buf);
 		if (try_path == NULL) {
+			free(try_path_buf);
 			/*
 			 * There was an error, we just want to be assured it
 			 * is linked to an unexistent directory, if it's another
@@ -109,6 +128,7 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 			}
 		} else {
 			/* Save the place we are before trying the next step */
+			try_path_buf = NULL;
 			free(try_path_prev);
 			try_path_prev = try_path;
 			prev = next;
@@ -116,7 +136,8 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 
 		/* Free the allocated memory */
 		free(cut_path);
-	};
+		cut_path = NULL;
+	}
 
 	/* Allocate memory for the resolved path if necessary */
 	if (resolved_path == NULL) {
@@ -142,6 +163,10 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 		 * path are pointers for the same memory space
 		 */
 		cut_path = strdup(prev);
+		if (cut_path == NULL) {
+			PERROR("strdup");
+			goto error;
+		}
 
 		/* Concatenate the strings */
 		snprintf(resolved_path, size, "%s%s", try_path_prev, cut_path);
@@ -149,6 +174,8 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 		/* Free the allocated memory */
 		free(cut_path);
 		free(try_path_prev);
+		cut_path = NULL;
+		try_path_prev = NULL;
 	/*
 	 * Else, we just copy the path in our resolved_path to
 	 * return it as is
@@ -162,9 +189,114 @@ char *utils_partial_realpath(const char *path, char *resolved_path, size_t size)
 
 error:
 	free(resolved_path);
+	free(cut_path);
+	free(try_path);
+	if (try_path_prev != try_path) {
+		free(try_path_prev);
+	}
 	return NULL;
 }
 
+static
+int expand_double_slashes_dot_and_dotdot(char *path)
+{
+	size_t expanded_path_len, path_len;
+	const char *curr_char, *path_last_char, *next_slash, *prev_slash;
+
+	path_len = strlen(path);
+	path_last_char = &path[path_len];
+
+	if (path_len == 0) {
+		goto error;
+	}
+
+	expanded_path_len = 0;
+
+	/* We iterate over the provided path to expand the "//", "../" and "./" */
+	for (curr_char = path; curr_char <= path_last_char; curr_char = next_slash + 1) {
+		/* Find the next forward slash. */
+		size_t curr_token_len;
+
+		if (curr_char == path_last_char) {
+			expanded_path_len++;
+			break;
+		}
+
+		next_slash = memchr(curr_char, '/', path_last_char - curr_char);
+		if (next_slash == NULL) {
+			/* Reached the end of the provided path. */
+			next_slash = path_last_char;
+		}
+
+		/* Compute how long is the previous token. */
+		curr_token_len = next_slash - curr_char;
+		switch(curr_token_len) {
+		case 0:
+			/*
+			 * The pointer has not move meaning that curr_char is
+			 * pointing to a slash. It that case there is no token
+			 * to copy, so continue the iteration to find the next
+			 * token
+			 */
+			continue;
+		case 1:
+			/*
+			 * The pointer moved 1 character. Check if that
+			 * character is a dot ('.'), if it is: omit it, else
+			 * copy the token to the normalized path.
+			 */
+			if (curr_char[0] == '.') {
+				continue;
+			}
+			break;
+		case 2:
+			/*
+			 * The pointer moved 2 characters. Check if these
+			 * characters are double dots ('..'). If that is the
+			 * case, we need to remove the last token of the
+			 * normalized path.
+			 */
+			if (curr_char[0] == '.' && curr_char[1] == '.') {
+				/*
+				 * Find the previous path component by
+				 * using the memrchr function to find the
+				 * previous forward slash and substract that
+				 * len to the resulting path.
+				 */
+				prev_slash = lttng_memrchr(path, '/', expanded_path_len);
+				/*
+				 * If prev_slash is NULL, we reached the
+				 * beginning of the path. We can't go back any
+				 * further.
+				 */
+				if (prev_slash != NULL) {
+					expanded_path_len = prev_slash - path;
+				}
+				continue;
+			}
+			break;
+		default:
+			break;
+		}
+
+		/*
+		 * Copy the current token which is neither a '.' nor a '..'.
+		 */
+		path[expanded_path_len++] = '/';
+		memcpy(&path[expanded_path_len], curr_char, curr_token_len);
+		expanded_path_len += curr_token_len;
+	}
+
+	if (expanded_path_len == 0) {
+		path[expanded_path_len++] = '/';
+	}
+
+	path[expanded_path_len] = '\0';
+	return 0;
+error:
+	return -1;
+}
+
 /*
  * Make a full resolution of the given path even if it doesn't exist.
  * This function uses the utils_partial_realpath function to resolve
@@ -176,11 +308,12 @@ error:
  * the responsibility of the caller to free this memory.
  */
 LTTNG_HIDDEN
-char *utils_expand_path(const char *path)
+char *_utils_expand_path(const char *path, bool keep_symlink)
 {
-	char *next, *previous, *slash, *start_path, *absolute_path = NULL;
+	int ret;
+	char *absolute_path = NULL;
 	char *last_token;
-	int is_dot, is_dotdot;
+	bool is_dot, is_dotdot;
 
 	/* Safety net */
 	if (path == NULL) {
@@ -188,60 +321,52 @@ char *utils_expand_path(const char *path)
 	}
 
 	/* Allocate memory for the absolute_path */
-	absolute_path = zmalloc(PATH_MAX);
+	absolute_path = zmalloc(LTTNG_PATH_MAX);
 	if (absolute_path == NULL) {
 		PERROR("zmalloc expand path");
 		goto error;
 	}
 
-	/*
-	 * If the path is not already absolute nor explicitly relative,
-	 * consider we're in the current directory
-	 */
-	if (*path != '/' && strncmp(path, "./", 2) != 0 &&
-			strncmp(path, "../", 3) != 0) {
-		snprintf(absolute_path, PATH_MAX, "./%s", path);
-	/* Else, we just copy the path */
+	if (path[0] == '/') {
+		ret = lttng_strncpy(absolute_path, path, LTTNG_PATH_MAX);
+		if (ret) {
+			ERR("Path exceeds maximal size of %i bytes", LTTNG_PATH_MAX);
+			goto error;
+		}
 	} else {
-		strncpy(absolute_path, path, PATH_MAX);
-	}
-
-	/* Resolve partially our path */
-	absolute_path = utils_partial_realpath(absolute_path,
-			absolute_path, PATH_MAX);
-
-	/* As long as we find '/./' in the working_path string */
-	while ((next = strstr(absolute_path, "/./"))) {
-
-		/* We prepare the start_path not containing it */
-		start_path = strndup(absolute_path, next - absolute_path);
-
-		/* And we concatenate it with the part after this string */
-		snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 2);
-
-		free(start_path);
-	}
+		/*
+		 * This is a relative path. We need to get the present working
+		 * directory and start the path walk from there.
+		 */
+		char current_working_dir[LTTNG_PATH_MAX];
+		char *cwd_ret;
 
-	/* As long as we find '/../' in the working_path string */
-	while ((next = strstr(absolute_path, "/../"))) {
-		/* We find the last level of directory */
-		previous = absolute_path;
-		while ((slash = strpbrk(previous, "/")) && slash != next) {
-			previous = slash + 1;
+		cwd_ret = getcwd(current_working_dir, sizeof(current_working_dir));
+		if (!cwd_ret) {
+			goto error;
 		}
+		/*
+		 * Get the number of character in the CWD and allocate an array
+		 * to can hold it and the path provided by the caller.
+		 */
+		ret = snprintf(absolute_path, LTTNG_PATH_MAX, "%s/%s",
+				current_working_dir, path);
+		if (ret >= LTTNG_PATH_MAX) {
+			ERR("Concatenating current working directory %s and path %s exceeds maximal size of %i bytes",
+					current_working_dir, path, LTTNG_PATH_MAX);
+			goto error;
+		}
+	}
 
-		/* Then we prepare the start_path not containing it */
-		start_path = strndup(absolute_path, previous - absolute_path);
-
-		/* And we concatenate it with the part after the '/../' */
-		snprintf(absolute_path, PATH_MAX, "%s%s", start_path, next + 4);
-
-		/* We can free the memory used for the start path*/
-		free(start_path);
-
-		/* Then we verify for symlinks using partial_realpath */
+	if (keep_symlink) {
+		/* Resolve partially our path */
 		absolute_path = utils_partial_realpath(absolute_path,
-				absolute_path, PATH_MAX);
+				absolute_path, LTTNG_PATH_MAX);
+	}
+
+	ret = expand_double_slashes_dot_and_dotdot(absolute_path);
+	if (ret) {
+		goto error;
 	}
 
 	/* Identify the last token */
@@ -275,7 +400,17 @@ error:
 	free(absolute_path);
 	return NULL;
 }
+LTTNG_HIDDEN
+char *utils_expand_path(const char *path)
+{
+	return _utils_expand_path(path, true);
+}
 
+LTTNG_HIDDEN
+char *utils_expand_path_keep_symlink(const char *path)
+{
+	return _utils_expand_path(path, false);
+}
 /*
  * Create a pipe in dst.
  */
@@ -457,24 +592,142 @@ int utils_create_pid_file(pid_t pid, const char *filepath)
 		goto error;
 	}
 
-	ret = fprintf(fp, "%d\n", pid);
+	ret = fprintf(fp, "%d\n", (int) pid);
 	if (ret < 0) {
 		PERROR("fprintf pid file");
+		goto error;
 	}
 
-	fclose(fp);
-	DBG("Pid %d written in file %s", pid, filepath);
+	if (fclose(fp)) {
+		PERROR("fclose");
+	}
+	DBG("Pid %d written in file %s", (int) pid, filepath);
+	ret = 0;
 error:
 	return ret;
 }
 
 /*
- * Recursively create directory using the given path and mode.
+ * Create lock file to the given path and filename.
+ * Returns the associated file descriptor, -1 on error.
+ */
+LTTNG_HIDDEN
+int utils_create_lock_file(const char *filepath)
+{
+	int ret;
+	int fd;
+	struct flock lock;
+
+	assert(filepath);
+
+	memset(&lock, 0, sizeof(lock));
+	fd = open(filepath, O_CREAT | O_WRONLY, S_IRUSR | S_IWUSR |
+		S_IRGRP | S_IWGRP);
+	if (fd < 0) {
+		PERROR("open lock file %s", filepath);
+		fd = -1;
+		goto error;
+	}
+
+	/*
+	 * Attempt to lock the file. If this fails, there is
+	 * already a process using the same lock file running
+	 * and we should exit.
+	 */
+	lock.l_whence = SEEK_SET;
+	lock.l_type = F_WRLCK;
+
+	ret = fcntl(fd, F_SETLK, &lock);
+	if (ret == -1) {
+		PERROR("fcntl lock file");
+		ERR("Could not get lock file %s, another instance is running.",
+			filepath);
+		if (close(fd)) {
+			PERROR("close lock file");
+		}
+		fd = ret;
+		goto error;
+	}
+
+error:
+	return fd;
+}
+
+/*
+ * On some filesystems (e.g. nfs), mkdir will validate access rights before
+ * checking for the existence of the path element. This means that on a setup
+ * where "/home/" is a mounted NFS share, and running as an unpriviledged user,
+ * recursively creating a path of the form "/home/my_user/trace/" will fail with
+ * EACCES on mkdir("/home", ...).
+ *
+ * Performing a stat(...) on the path to check for existence allows us to
+ * work around this behaviour.
+ */
+static
+int mkdir_check_exists(const char *path, mode_t mode)
+{
+	int ret = 0;
+	struct stat st;
+
+	ret = stat(path, &st);
+	if (ret == 0) {
+		if (S_ISDIR(st.st_mode)) {
+			/* Directory exists, skip. */
+			goto end;
+		} else {
+			/* Exists, but is not a directory. */
+			errno = ENOTDIR;
+			ret = -1;
+			goto end;
+		}
+	}
+
+	/*
+	 * Let mkdir handle other errors as the caller expects mkdir
+	 * semantics.
+	 */
+	ret = mkdir(path, mode);
+end:
+	return ret;
+}
+
+/*
+ * Create directory using the given path and mode.
  *
  * On success, return 0 else a negative error code.
  */
 LTTNG_HIDDEN
-int utils_mkdir_recursive(const char *path, mode_t mode)
+int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
+{
+	int ret;
+
+	if (uid < 0 || gid < 0) {
+		ret = mkdir_check_exists(path, mode);
+	} else {
+		ret = run_as_mkdir(path, mode, uid, gid);
+	}
+	if (ret < 0) {
+		if (errno != EEXIST) {
+			PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
+					uid, gid);
+		} else {
+			ret = 0;
+		}
+	}
+
+	return ret;
+}
+
+/*
+ * Internal version of mkdir_recursive. Runs as the current user.
+ * Don't call directly; use utils_mkdir_recursive().
+ *
+ * This function is ominously marked as "unsafe" since it should only
+ * be called by a caller that has transitioned to the uid and gid under which
+ * the directory creation should occur.
+ */
+LTTNG_HIDDEN
+int _utils_mkdir_recursive_unsafe(const char *path, mode_t mode)
 {
 	char *p, tmp[PATH_MAX];
 	size_t len;
@@ -504,9 +757,9 @@ int utils_mkdir_recursive(const char *path, mode_t mode)
 				ret = -1;
 				goto error;
 			}
-			ret = mkdir(tmp, mode);
+			ret = mkdir_check_exists(tmp, mode);
 			if (ret < 0) {
-				if (errno != EEXIST) {
+				if (errno != EACCES) {
 					PERROR("mkdir recursive");
 					ret = -errno;
 					goto error;
@@ -516,14 +769,10 @@ int utils_mkdir_recursive(const char *path, mode_t mode)
 		}
 	}
 
-	ret = mkdir(tmp, mode);
+	ret = mkdir_check_exists(tmp, mode);
 	if (ret < 0) {
-		if (errno != EEXIST) {
-			PERROR("mkdir recursive last piece");
-			ret = -errno;
-		} else {
-			ret = 0;
-		}
+		PERROR("mkdir recursive last element");
+		ret = -errno;
 	}
 
 error:
@@ -531,20 +780,44 @@ error:
 }
 
 /*
- * Create the stream tracefile on disk.
+ * Recursively create directory using the given path and mode, under the
+ * provided uid and gid.
  *
- * Return 0 on success or else a negative value.
+ * On success, return 0 else a negative error code.
  */
 LTTNG_HIDDEN
-int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
-		uint64_t count, int uid, int gid, char *suffix)
+int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
 {
-	int ret, out_fd, flags, mode;
-	char full_path[PATH_MAX], *path_name_suffix = NULL, *path;
-	char *extra = NULL;
+	int ret;
 
-	assert(path_name);
-	assert(file_name);
+	if (uid < 0 || gid < 0) {
+		/* Run as current user. */
+		ret = _utils_mkdir_recursive_unsafe(path, mode);
+	} else {
+		ret = run_as_mkdir_recursive(path, mode, uid, gid);
+	}
+	if (ret < 0) {
+		PERROR("mkdir %s, uid %d, gid %d", path ? path : "NULL",
+				uid, gid);
+	}
+
+	return ret;
+}
+
+/*
+ * path is the output parameter. It needs to be PATH_MAX len.
+ *
+ * Return 0 on success or else a negative value.
+ */
+static int utils_stream_file_name(char *path,
+		const char *path_name, const char *file_name,
+		uint64_t size, uint64_t count,
+		const char *suffix)
+{
+	int ret;
+	char full_path[PATH_MAX];
+	char *path_name_suffix = NULL;
+	char *extra = NULL;
 
 	ret = snprintf(full_path, sizeof(full_path), "%s/%s",
 			path_name, file_name);
@@ -567,8 +840,8 @@ int utils_create_stream_file(const char *path_name, char *file_name, uint64_t si
 	}
 
 	/*
-	 * If we split the trace in multiple files, we have to add the count at the
-	 * end of the tracefile name
+	 * If we split the trace in multiple files, we have to add the count at
+	 * the end of the tracefile name.
 	 */
 	if (extra) {
 		ret = asprintf(&path_name_suffix, "%s%s", full_path, extra);
@@ -576,31 +849,90 @@ int utils_create_stream_file(const char *path_name, char *file_name, uint64_t si
 			PERROR("Allocating path name with extra string");
 			goto error_free_suffix;
 		}
-		path = path_name_suffix;
+		strncpy(path, path_name_suffix, PATH_MAX - 1);
+		path[PATH_MAX - 1] = '\0';
 	} else {
-		path = full_path;
+		ret = lttng_strncpy(path, full_path, PATH_MAX);
+		if (ret) {
+			ERR("Failed to copy stream file name");
+			goto error_free_suffix;
+		}
 	}
+	path[PATH_MAX - 1] = '\0';
+	ret = 0;
 
-	flags = O_WRONLY | O_CREAT | O_TRUNC;
+	free(path_name_suffix);
+error_free_suffix:
+	free(extra);
+error:
+	return ret;
+}
+
+/*
+ * Create the stream file on disk.
+ *
+ * Return 0 on success or else a negative value.
+ */
+LTTNG_HIDDEN
+int utils_create_stream_file(const char *path_name, char *file_name, uint64_t size,
+		uint64_t count, int uid, int gid, char *suffix)
+{
+	int ret, flags, mode;
+	char path[PATH_MAX];
+
+	ret = utils_stream_file_name(path, path_name, file_name,
+			size, count, suffix);
+	if (ret < 0) {
+		goto error;
+	}
+
+	/*
+	 * With the session rotation feature on the relay, we might need to seek
+	 * and truncate a tracefile, so we need read and write access.
+	 */
+	flags = O_RDWR | O_CREAT | O_TRUNC;
 	/* Open with 660 mode */
 	mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP;
 
 	if (uid < 0 || gid < 0) {
-		out_fd = open(path, flags, mode);
+		ret = open(path, flags, mode);
 	} else {
-		out_fd = run_as_open(path, flags, mode, uid, gid);
+		ret = run_as_open(path, flags, mode, uid, gid);
 	}
-	if (out_fd < 0) {
+	if (ret < 0) {
 		PERROR("open stream path %s", path);
-		goto error_open;
 	}
-	ret = out_fd;
+error:
+	return ret;
+}
 
-error_open:
-	free(path_name_suffix);
-error_free_suffix:
-	free(extra);
+/*
+ * Unlink the stream tracefile from disk.
+ *
+ * Return 0 on success or else a negative value.
+ */
+LTTNG_HIDDEN
+int utils_unlink_stream_file(const char *path_name, char *file_name, uint64_t size,
+		uint64_t count, int uid, int gid, char *suffix)
+{
+	int ret;
+	char path[PATH_MAX];
+
+	ret = utils_stream_file_name(path, path_name, file_name,
+			size, count, suffix);
+	if (ret < 0) {
+		goto error;
+	}
+	if (uid < 0 || gid < 0) {
+		ret = unlink(path);
+	} else {
+		ret = run_as_unlink(path, uid, gid);
+	}
+	if (ret < 0) {
+		goto error;
+	}
 error:
+	DBG("utils_unlink_stream_file %s returns %d", path, ret);
 	return ret;
 }
 
@@ -620,7 +952,6 @@ int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
 {
 	int ret;
 
-	assert(new_count);
 	assert(stream_fd);
 
 	ret = close(out_fd);
@@ -628,15 +959,38 @@ int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
 		PERROR("Closing tracefile");
 		goto error;
 	}
+	*stream_fd = -1;
 
 	if (count > 0) {
-		*new_count = (*new_count + 1) % count;
+		/*
+		 * In tracefile rotation, for the relay daemon we need
+		 * to unlink the old file if present, because it may
+		 * still be open in reading by the live thread, and we
+		 * need to ensure that we do not overwrite the content
+		 * between get_index and get_packet. Since we have no
+		 * way to verify integrity of the data content compared
+		 * to the associated index, we need to ensure the reader
+		 * has exclusive access to the file content, and that
+		 * the open of the data file is performed in get_index.
+		 * Unlinking the old file rather than overwriting it
+		 * achieves this.
+		 */
+		if (new_count) {
+			*new_count = (*new_count + 1) % count;
+		}
+		ret = utils_unlink_stream_file(path_name, file_name, size,
+				new_count ? *new_count : 0, uid, gid, 0);
+		if (ret < 0 && errno != ENOENT) {
+			goto error;
+		}
 	} else {
-		(*new_count)++;
+		if (new_count) {
+			(*new_count)++;
+		}
 	}
 
-	ret = utils_create_stream_file(path_name, file_name, size, *new_count,
-			uid, gid, 0);
+	ret = utils_create_stream_file(path_name, file_name, size,
+			new_count ? *new_count : 0, uid, gid, 0);
 	if (ret < 0) {
 		goto error;
 	}
@@ -748,6 +1102,134 @@ end:
 	return ret;
 }
 
+/**
+ * Parse a string that represents a time in human readable format. It
+ * supports decimal integers suffixed by:
+ *     "us" for microsecond,
+ *     "ms" for millisecond,
+ *     "s"  for second,
+ *     "m"  for minute,
+ *     "h"  for hour
+ *
+ * The suffix multiply the integer by:
+ *     "us" : 1
+ *     "ms" : 1000
+ *     "s"  : 1000000
+ *     "m"  : 60000000
+ *     "h"  : 3600000000
+ *
+ * Note that unit-less numbers are assumed to be microseconds.
+ *
+ * @param str		The string to parse, assumed to be NULL-terminated.
+ * @param time_us	Pointer to a uint64_t that will be filled with the
+ *			resulting time in microseconds.
+ *
+ * @return 0 on success, -1 on failure.
+ */
+LTTNG_HIDDEN
+int utils_parse_time_suffix(char const * const str, uint64_t * const time_us)
+{
+	int ret;
+	uint64_t base_time;
+	uint64_t multiplier = 1;
+	const char *str_end;
+	char *num_end;
+
+	if (!str) {
+		DBG("utils_parse_time_suffix: received a NULL string.");
+		ret = -1;
+		goto end;
+	}
+
+	/* strtoull will accept a negative number, but we don't want to. */
+	if (strchr(str, '-') != NULL) {
+		DBG("utils_parse_time_suffix: invalid time string, should not contain '-'.");
+		ret = -1;
+		goto end;
+	}
+
+	/* str_end will point to the \0 */
+	str_end = str + strlen(str);
+	errno = 0;
+	base_time = strtoull(str, &num_end, 10);
+	if (errno != 0) {
+		PERROR("utils_parse_time_suffix strtoull on string \"%s\"", str);
+		ret = -1;
+		goto end;
+	}
+
+	if (num_end == str) {
+		/* strtoull parsed nothing, not good. */
+		DBG("utils_parse_time_suffix: strtoull had nothing good to parse.");
+		ret = -1;
+		goto end;
+	}
+
+	/* Check if a prefix is present. */
+	switch (*num_end) {
+	case 'u':
+		/*
+		 * Microsecond (us)
+		 *
+		 * Skip the "us" if the string matches the "us" suffix,
+		 * otherwise let the check for the end of the string handle
+		 * the error reporting.
+		 */
+		if (*(num_end + 1) == 's') {
+			num_end += 2;
+		}
+		break;
+	case 'm':
+		if (*(num_end + 1) == 's') {
+			/* Millisecond (ms) */
+			multiplier = USEC_PER_MSEC;
+			/* Skip the 's' */
+			num_end++;
+		} else {
+			/* Minute (m) */
+			multiplier = USEC_PER_MINUTE;
+		}
+		num_end++;
+		break;
+	case 's':
+		/* Second */
+		multiplier = USEC_PER_SEC;
+		num_end++;
+		break;
+	case 'h':
+		/* Hour */
+		multiplier = USEC_PER_HOURS;
+		num_end++;
+		break;
+	case '\0':
+		break;
+	default:
+		DBG("utils_parse_time_suffix: invalid suffix.");
+		ret = -1;
+		goto end;
+	}
+
+	/* Check for garbage after the valid input. */
+	if (num_end != str_end) {
+		DBG("utils_parse_time_suffix: Garbage after time string.");
+		ret = -1;
+		goto end;
+	}
+
+	*time_us = base_time * multiplier;
+
+	/* Check for overflow */
+	if ((*time_us / multiplier) != base_time) {
+		DBG("utils_parse_time_suffix: oops, overflow detected.");
+		ret = -1;
+		goto end;
+	}
+
+	ret = 0;
+end:
+	return ret;
+}
+
 /*
  * fls: returns the position of the most significant bit.
  * Returns 0 if no bit is set, else returns the position of the most
@@ -768,6 +1250,59 @@ static inline unsigned int fls_u32(uint32_t x)
 #define HAS_FLS_U32
 #endif
 
+#if defined(__x86_64)
+static inline
+unsigned int fls_u64(uint64_t x)
+{
+	long r;
+
+	asm("bsrq %1,%0\n\t"
+	    "jnz 1f\n\t"
+	    "movq $-1,%0\n\t"
+	    "1:\n\t"
+	    : "=r" (r) : "rm" (x));
+	return r + 1;
+}
+#define HAS_FLS_U64
+#endif
+
+#ifndef HAS_FLS_U64
+static __attribute__((unused))
+unsigned int fls_u64(uint64_t x)
+{
+	unsigned int r = 64;
+
+	if (!x)
+		return 0;
+
+	if (!(x & 0xFFFFFFFF00000000ULL)) {
+		x <<= 32;
+		r -= 32;
+	}
+	if (!(x & 0xFFFF000000000000ULL)) {
+		x <<= 16;
+		r -= 16;
+	}
+	if (!(x & 0xFF00000000000000ULL)) {
+		x <<= 8;
+		r -= 8;
+	}
+	if (!(x & 0xF000000000000000ULL)) {
+		x <<= 4;
+		r -= 4;
+	}
+	if (!(x & 0xC000000000000000ULL)) {
+		x <<= 2;
+		r -= 2;
+	}
+	if (!(x & 0x8000000000000000ULL)) {
+		x <<= 1;
+		r -= 1;
+	}
+	return r;
+}
+#endif
+
 #ifndef HAS_FLS_U32
 static __attribute__((unused)) unsigned int fls_u32(uint32_t x)
 {
@@ -814,6 +1349,20 @@ int utils_get_count_order_u32(uint32_t x)
 	return fls_u32(x - 1);
 }
 
+/*
+ * Return the minimum order for which x <= (1UL << order).
+ * Return -1 if x is 0.
+ */
+LTTNG_HIDDEN
+int utils_get_count_order_u64(uint64_t x)
+{
+	if (!x) {
+		return -1;
+	}
+
+	return fls_u64(x - 1);
+}
+
 /**
  * Obtain the value of LTTNG_HOME environment variable, if exists.
  * Otherwise returns the value of HOME.
@@ -822,11 +1371,28 @@ LTTNG_HIDDEN
 char *utils_get_home_dir(void)
 {
 	char *val = NULL;
-	val = getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
+	struct passwd *pwd;
+
+	val = lttng_secure_getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
+	if (val != NULL) {
+		goto end;
+	}
+	val = lttng_secure_getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
 	if (val != NULL) {
-		return val;
+		goto end;
 	}
-	return getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
+
+	/* Fallback on the password file entry. */
+	pwd = getpwuid(getuid());
+	if (!pwd) {
+		goto end;
+	}
+	val = pwd->pw_dir;
+
+	DBG3("Home directory is '%s'", val);
+
+end:
+	return val;
 }
 
 /**
@@ -869,16 +1435,6 @@ end:
 	return home_dir;
 }
 
-/*
- * Obtain the value of LTTNG_KMOD_PROBES environment variable, if exists.
- * Otherwise returns an empty string.
- */
-LTTNG_HIDDEN
-char *utils_get_kmod_probes_list(void)
-{
-	return getenv(DEFAULT_LTTNG_KMOD_PROBES);
-}
-
 /*
  * With the given format, fill dst with the time of len maximum siz.
  *
@@ -960,12 +1516,160 @@ char *utils_generate_optstring(const struct option *long_options,
 			break;
 		}
 
-		optstring[str_pos++] = (char)long_options[i].val;
-		if (long_options[i].has_arg) {
-			optstring[str_pos++] = ':';
+		if (long_options[i].val != '\0') {
+			optstring[str_pos++] = (char) long_options[i].val;
+			if (long_options[i].has_arg) {
+				optstring[str_pos++] = ':';
+			}
 		}
 	}
 
 end:
 	return optstring;
 }
+
+/*
+ * Try to remove a hierarchy of empty directories, recursively. Don't unlink
+ * any file. Try to rmdir any empty directory within the hierarchy.
+ */
+LTTNG_HIDDEN
+int utils_recursive_rmdir(const char *path)
+{
+	DIR *dir;
+	size_t path_len;
+	int dir_fd, ret = 0, closeret, is_empty = 1;
+	struct dirent *entry;
+
+	/* Open directory */
+	dir = opendir(path);
+	if (!dir) {
+		PERROR("Cannot open '%s' path", path);
+		return -1;
+	}
+	dir_fd = lttng_dirfd(dir);
+	if (dir_fd < 0) {
+		PERROR("lttng_dirfd");
+		return -1;
+	}
+
+	path_len = strlen(path);
+	while ((entry = readdir(dir))) {
+		struct stat st;
+		size_t name_len;
+		char filename[PATH_MAX];
+
+		if (!strcmp(entry->d_name, ".")
+				|| !strcmp(entry->d_name, "..")) {
+			continue;
+		}
+
+		name_len = strlen(entry->d_name);
+		if (path_len + name_len + 2 > sizeof(filename)) {
+			ERR("Failed to remove file: path name too long (%s/%s)",
+				path, entry->d_name);
+			continue;
+		}
+		if (snprintf(filename, sizeof(filename), "%s/%s",
+				path, entry->d_name) < 0) {
+			ERR("Failed to format path.");
+			continue;
+		}
+
+		if (stat(filename, &st)) {
+			PERROR("stat");
+			continue;
+		}
+
+		if (S_ISDIR(st.st_mode)) {
+			char subpath[PATH_MAX];
+
+			strncpy(subpath, path, PATH_MAX);
+			subpath[PATH_MAX - 1] = '\0';
+			strncat(subpath, "/",
+				PATH_MAX - strlen(subpath) - 1);
+			strncat(subpath, entry->d_name,
+				PATH_MAX - strlen(subpath) - 1);
+			if (utils_recursive_rmdir(subpath)) {
+				is_empty = 0;
+			}
+		} else if (S_ISREG(st.st_mode)) {
+			is_empty = 0;
+		} else {
+			ret = -EINVAL;
+			goto end;
+		}
+	}
+end:
+	closeret = closedir(dir);
+	if (closeret) {
+		PERROR("closedir");
+	}
+	if (is_empty) {
+		DBG3("Attempting rmdir %s", path);
+		ret = rmdir(path);
+	}
+	return ret;
+}
+
+LTTNG_HIDDEN
+int utils_truncate_stream_file(int fd, off_t length)
+{
+	int ret;
+	off_t lseek_ret;
+
+	ret = ftruncate(fd, length);
+	if (ret < 0) {
+		PERROR("ftruncate");
+		goto end;
+	}
+	lseek_ret = lseek(fd, length, SEEK_SET);
+	if (lseek_ret < 0) {
+		PERROR("lseek");
+		ret = -1;
+		goto end;
+	}
+end:
+	return ret;
+}
+
+static const char *get_man_bin_path(void)
+{
+	char *env_man_path = lttng_secure_getenv(DEFAULT_MAN_BIN_PATH_ENV);
+
+	if (env_man_path) {
+		return env_man_path;
+	}
+
+	return DEFAULT_MAN_BIN_PATH;
+}
+
+LTTNG_HIDDEN
+int utils_show_help(int section, const char *page_name,
+		const char *help_msg)
+{
+	char section_string[8];
+	const char *man_bin_path = get_man_bin_path();
+	int ret = 0;
+
+	if (help_msg) {
+		printf("%s", help_msg);
+		goto end;
+	}
+
+	/* Section integer -> section string */
+	ret = sprintf(section_string, "%d", section);
+	assert(ret > 0 && ret < 8);
+
+	/*
+	 * Execute man pager.
+	 *
+	 * We provide -M to man here because LTTng-tools can
+	 * be installed outside /usr, in which case its man pages are
+	 * not located in the default /usr/share/man directory.
+	 */
+	ret = execlp(man_bin_path, "man", "-M", MANPATH,
+		section_string, page_name, NULL);
+
+end:
+	return ret;
+}