+
+/*
+ * Set CLOEXEC flag to the give file descriptor.
+ */
+LTTNG_HIDDEN
+int utils_set_fd_cloexec(int fd)
+{
+ int ret;
+
+ if (fd < 0) {
+ ret = -EINVAL;
+ goto end;
+ }
+
+ ret = fcntl(fd, F_SETFD, FD_CLOEXEC);
+ if (ret < 0) {
+ PERROR("fcntl cloexec");
+ ret = -errno;
+ }
+
+end:
+ return ret;
+}
+
+/*
+ * Create pid file to the given path and filename.
+ */
+LTTNG_HIDDEN
+int utils_create_pid_file(pid_t pid, const char *filepath)
+{
+ int ret;
+ FILE *fp;
+
+ assert(filepath);
+
+ fp = fopen(filepath, "w");
+ if (fp == NULL) {
+ PERROR("open pid file %s", filepath);
+ ret = -1;
+ goto error;
+ }
+
+ ret = fprintf(fp, "%d\n", (int) pid);
+ if (ret < 0) {
+ PERROR("fprintf pid file");
+ goto error;
+ }
+
+ if (fclose(fp)) {
+ PERROR("fclose");
+ }
+ DBG("Pid %d written in file %s", (int) pid, filepath);
+ ret = 0;
+error:
+ return ret;
+}
+
+/*
+ * 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;
+}
+
+/*
+ * Create directory using the given path and mode.
+ *
+ * On success, return 0 else a negative error code.
+ */
+LTTNG_HIDDEN
+int utils_mkdir(const char *path, mode_t mode, int uid, int gid)
+{
+ int ret;
+ struct lttng_directory_handle *handle;
+ const struct lttng_credentials creds = {
+ .uid = (uid_t) uid,
+ .gid = (gid_t) gid,
+ };
+
+ handle = lttng_directory_handle_create(NULL);
+ if (!handle) {
+ ret = -1;
+ goto end;
+ }
+ ret = lttng_directory_handle_create_subdirectory_as_user(
+ handle, path, mode,
+ (uid >= 0 || gid >= 0) ? &creds : NULL);
+end:
+ lttng_directory_handle_put(handle);
+ return ret;
+}
+
+/*
+ * Recursively create directory using the given path and mode, under the
+ * provided uid and gid.
+ *
+ * On success, return 0 else a negative error code.
+ */
+LTTNG_HIDDEN
+int utils_mkdir_recursive(const char *path, mode_t mode, int uid, int gid)
+{
+ int ret;
+ struct lttng_directory_handle *handle;
+ const struct lttng_credentials creds = {
+ .uid = (uid_t) uid,
+ .gid = (gid_t) gid,
+ };
+
+ handle = lttng_directory_handle_create(NULL);
+ if (!handle) {
+ ret = -1;
+ goto end;
+ }
+ ret = lttng_directory_handle_create_subdirectory_recursive_as_user(
+ handle, path, mode,
+ (uid >= 0 || gid >= 0) ? &creds : NULL);
+end:
+ lttng_directory_handle_put(handle);
+ return ret;
+}
+
+/*
+ * out_stream_path is the output parameter.
+ *
+ * Return 0 on success or else a negative value.
+ */
+LTTNG_HIDDEN
+int utils_stream_file_path(const char *path_name, const char *file_name,
+ uint64_t size, uint64_t count, const char *suffix,
+ char *out_stream_path, size_t stream_path_len)
+{
+ int ret;
+ char count_str[MAX_INT_DEC_LEN(count) + 1] = {};
+ const char *path_separator;
+
+ if (path_name && (path_name[0] == '\0' ||
+ path_name[strlen(path_name) - 1] == '/')) {
+ path_separator = "";
+ } else {
+ path_separator = "/";
+ }
+
+ path_name = path_name ? : "";
+ suffix = suffix ? : "";
+ if (size > 0) {
+ ret = snprintf(count_str, sizeof(count_str), "_%" PRIu64,
+ count);
+ assert(ret > 0 && ret < sizeof(count_str));
+ }
+
+ ret = snprintf(out_stream_path, stream_path_len, "%s%s%s%s%s",
+ path_name, path_separator, file_name, count_str,
+ suffix);
+ if (ret < 0 || ret >= stream_path_len) {
+ ERR("Truncation occurred while formatting stream path");
+ ret = -1;
+ } else {
+ ret = 0;
+ }
+ return ret;
+}
+
+/**
+ * Parse a string that represents a size in human readable format. It
+ * supports decimal integers suffixed by 'k', 'K', 'M' or 'G'.
+ *
+ * The suffix multiply the integer by:
+ * 'k': 1024
+ * 'M': 1024^2
+ * 'G': 1024^3
+ *
+ * @param str The string to parse.
+ * @param size Pointer to a uint64_t that will be filled with the
+ * resulting size.
+ *
+ * @return 0 on success, -1 on failure.
+ */
+LTTNG_HIDDEN
+int utils_parse_size_suffix(const char * const str, uint64_t * const size)
+{
+ int ret;
+ uint64_t base_size;
+ long shift = 0;
+ const char *str_end;
+ char *num_end;
+
+ if (!str) {
+ DBG("utils_parse_size_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_size_suffix: invalid size string, should not contain '-'.");
+ ret = -1;
+ goto end;
+ }
+
+ /* str_end will point to the \0 */
+ str_end = str + strlen(str);
+ errno = 0;
+ base_size = strtoull(str, &num_end, 0);
+ if (errno != 0) {
+ PERROR("utils_parse_size_suffix strtoull");
+ ret = -1;
+ goto end;
+ }
+
+ if (num_end == str) {
+ /* strtoull parsed nothing, not good. */
+ DBG("utils_parse_size_suffix: strtoull had nothing good to parse.");
+ ret = -1;
+ goto end;
+ }
+
+ /* Check if a prefix is present. */
+ switch (*num_end) {
+ case 'G':
+ shift = GIBI_LOG2;
+ num_end++;
+ break;
+ case 'M': /* */
+ shift = MEBI_LOG2;
+ num_end++;
+ break;
+ case 'K':
+ case 'k':
+ shift = KIBI_LOG2;
+ num_end++;
+ break;
+ case '\0':
+ break;
+ default:
+ DBG("utils_parse_size_suffix: invalid suffix.");
+ ret = -1;
+ goto end;
+ }
+
+ /* Check for garbage after the valid input. */
+ if (num_end != str_end) {
+ DBG("utils_parse_size_suffix: Garbage after size string.");
+ ret = -1;
+ goto end;
+ }
+
+ *size = base_size << shift;
+
+ /* Check for overflow */
+ if ((*size >> shift) != base_size) {
+ DBG("utils_parse_size_suffix: oops, overflow detected.");
+ ret = -1;
+ goto end;
+ }
+
+ ret = 0;
+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
+ * significant bit (from 1 to 32 on 32-bit, from 1 to 64 on 64-bit).
+ */
+#if defined(__i386) || defined(__x86_64)
+static inline unsigned int fls_u32(uint32_t x)
+{
+ int r;
+
+ asm("bsrl %1,%0\n\t"
+ "jnz 1f\n\t"
+ "movl $-1,%0\n\t"
+ "1:\n\t"
+ : "=r" (r) : "rm" (x));
+ return r + 1;
+}
+#define HAS_FLS_U32
+#endif
+
+#if defined(__x86_64) && defined(__LP64__)
+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)
+{
+ unsigned int r = 32;
+
+ if (!x) {
+ return 0;
+ }
+ if (!(x & 0xFFFF0000U)) {
+ x <<= 16;
+ r -= 16;
+ }
+ if (!(x & 0xFF000000U)) {
+ x <<= 8;
+ r -= 8;
+ }
+ if (!(x & 0xF0000000U)) {
+ x <<= 4;
+ r -= 4;
+ }
+ if (!(x & 0xC0000000U)) {
+ x <<= 2;
+ r -= 2;
+ }
+ if (!(x & 0x80000000U)) {
+ x <<= 1;
+ r -= 1;
+ }
+ return r;
+}
+#endif
+
+/*
+ * Return the minimum order for which x <= (1UL << order).
+ * Return -1 if x is 0.
+ */
+LTTNG_HIDDEN
+int utils_get_count_order_u32(uint32_t x)
+{
+ if (!x) {
+ return -1;
+ }
+
+ 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.
+ */
+LTTNG_HIDDEN
+const char *utils_get_home_dir(void)
+{
+ char *val = NULL;
+ 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) {
+ goto end;
+ }
+
+ /* 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;
+}
+
+/**
+ * Get user's home directory. Dynamically allocated, must be freed
+ * by the caller.
+ */
+LTTNG_HIDDEN
+char *utils_get_user_home_dir(uid_t uid)
+{
+ struct passwd pwd;
+ struct passwd *result;
+ char *home_dir = NULL;
+ char *buf = NULL;
+ long buflen;
+ int ret;
+
+ buflen = sysconf(_SC_GETPW_R_SIZE_MAX);
+ if (buflen == -1) {
+ goto end;
+ }
+retry:
+ buf = zmalloc(buflen);
+ if (!buf) {
+ goto end;
+ }
+
+ ret = getpwuid_r(uid, &pwd, buf, buflen, &result);
+ if (ret || !result) {
+ if (ret == ERANGE) {
+ free(buf);
+ buflen *= 2;
+ goto retry;
+ }
+ goto end;
+ }
+
+ home_dir = strdup(pwd.pw_dir);
+end:
+ free(buf);
+ return home_dir;
+}
+
+/*
+ * With the given format, fill dst with the time of len maximum siz.
+ *
+ * Return amount of bytes set in the buffer or else 0 on error.
+ */
+LTTNG_HIDDEN
+size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
+{
+ size_t ret;
+ time_t rawtime;
+ struct tm *timeinfo;
+
+ assert(format);
+ assert(dst);
+
+ /* Get date and time for session path */
+ time(&rawtime);
+ timeinfo = localtime(&rawtime);
+ ret = strftime(dst, len, format, timeinfo);
+ if (ret == 0) {
+ ERR("Unable to strftime with format %s at dst %p of len %zu", format,
+ dst, len);
+ }
+
+ return ret;
+}
+
+/*
+ * Return 0 on success and set *gid to the group_ID matching the passed name.
+ * Else -1 if it cannot be found or an error occurred.
+ */
+LTTNG_HIDDEN
+int utils_get_group_id(const char *name, bool warn, gid_t *gid)
+{
+ static volatile int warn_once;
+ int ret;
+ long sys_len;
+ size_t len;
+ struct group grp;
+ struct group *result;
+ struct lttng_dynamic_buffer buffer;
+
+ /* Get the system limit, if it exists. */
+ sys_len = sysconf(_SC_GETGR_R_SIZE_MAX);
+ if (sys_len == -1) {
+ len = 1024;
+ } else {
+ len = (size_t) sys_len;
+ }
+
+ lttng_dynamic_buffer_init(&buffer);
+ ret = lttng_dynamic_buffer_set_size(&buffer, len);
+ if (ret) {
+ ERR("Failed to allocate group info buffer");
+ ret = -1;
+ goto error;
+ }
+
+ while ((ret = getgrnam_r(name, &grp, buffer.data, buffer.size, &result)) == ERANGE) {
+ const size_t new_len = 2 * buffer.size;
+
+ /* Buffer is not big enough, increase its size. */
+ if (new_len < buffer.size) {
+ ERR("Group info buffer size overflow");
+ ret = -1;
+ goto error;
+ }
+
+ ret = lttng_dynamic_buffer_set_size(&buffer, new_len);
+ if (ret) {
+ ERR("Failed to grow group info buffer to %zu bytes",
+ new_len);
+ ret = -1;
+ goto error;
+ }
+ }
+ if (ret) {
+ PERROR("Failed to get group file entry for group name \"%s\"",
+ name);
+ ret = -1;
+ goto error;
+ }
+
+ /* Group not found. */
+ if (!result) {
+ ret = -1;
+ goto error;
+ }
+
+ *gid = result->gr_gid;
+ ret = 0;
+
+error:
+ if (ret && warn && !warn_once) {
+ WARN("No tracing group detected");
+ warn_once = 1;
+ }
+ lttng_dynamic_buffer_reset(&buffer);
+ return ret;
+}
+
+/*
+ * Return a newly allocated option string. This string is to be used as the
+ * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
+ * of elements in the long_options array. Returns NULL if the string's
+ * allocation fails.
+ */
+LTTNG_HIDDEN
+char *utils_generate_optstring(const struct option *long_options,
+ size_t opt_count)
+{
+ int i;
+ size_t string_len = opt_count, str_pos = 0;
+ char *optstring;
+
+ /*
+ * Compute the necessary string length. One letter per option, two when an
+ * argument is necessary, and a trailing NULL.
+ */
+ for (i = 0; i < opt_count; i++) {
+ string_len += long_options[i].has_arg ? 1 : 0;
+ }
+
+ optstring = zmalloc(string_len);
+ if (!optstring) {
+ goto end;
+ }
+
+ for (i = 0; i < opt_count; i++) {
+ if (!long_options[i].name) {
+ /* Got to the trailing NULL element */
+ break;
+ }
+
+ 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)
+{
+ int ret;
+ struct lttng_directory_handle *handle;
+
+ handle = lttng_directory_handle_create(NULL);
+ if (!handle) {
+ ret = -1;
+ goto end;
+ }
+ ret = lttng_directory_handle_remove_subdirectory(handle, path);
+end:
+ lttng_directory_handle_put(handle);
+ 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;
+}
+
+static
+int read_proc_meminfo_field(const char *field, size_t *value)
+{
+ int ret;
+ FILE *proc_meminfo;
+ char name[PROC_MEMINFO_FIELD_MAX_NAME_LEN] = {};
+
+ proc_meminfo = fopen(PROC_MEMINFO_PATH, "r");
+ if (!proc_meminfo) {
+ PERROR("Failed to fopen() " PROC_MEMINFO_PATH);
+ ret = -1;
+ goto fopen_error;
+ }
+
+ /*
+ * Read the contents of /proc/meminfo line by line to find the right
+ * field.
+ */
+ while (!feof(proc_meminfo)) {
+ unsigned long value_kb;
+
+ ret = fscanf(proc_meminfo,
+ "%" MAX_NAME_LEN_SCANF_IS_A_BROKEN_API "s %lu kB\n",
+ name, &value_kb);
+ if (ret == EOF) {
+ /*
+ * fscanf() returning EOF can indicate EOF or an error.
+ */
+ if (ferror(proc_meminfo)) {
+ PERROR("Failed to parse " PROC_MEMINFO_PATH);
+ }
+ break;
+ }
+
+ if (ret == 2 && strcmp(name, field) == 0) {
+ /*
+ * This number is displayed in kilo-bytes. Return the
+ * number of bytes.
+ */
+ *value = ((size_t) value_kb) * 1024;
+ ret = 0;
+ goto found;
+ }
+ }
+ /* Reached the end of the file without finding the right field. */
+ ret = -1;
+
+found:
+ fclose(proc_meminfo);
+fopen_error:
+ return ret;
+}
+
+/*
+ * Returns an estimate of the number of bytes of memory available based on the
+ * the information in `/proc/meminfo`. The number returned by this function is
+ * a best guess.
+ */
+LTTNG_HIDDEN
+int utils_get_memory_available(size_t *value)
+{
+ return read_proc_meminfo_field(PROC_MEMINFO_MEMAVAILABLE_LINE, value);
+}
+
+/*
+ * Returns the total size of the memory on the system in bytes based on the
+ * the information in `/proc/meminfo`.
+ */
+LTTNG_HIDDEN
+int utils_get_memory_total(size_t *value)
+{
+ return read_proc_meminfo_field(PROC_MEMINFO_MEMTOTAL_LINE, value);
+}
+
+LTTNG_HIDDEN
+int utils_change_working_directory(const char *path)
+{
+ int ret;
+
+ assert(path);
+
+ DBG("Changing working directory to \"%s\"", path);
+ ret = chdir(path);
+ if (ret) {
+ PERROR("Failed to change working directory to \"%s\"", path);
+ goto end;
+ }
+
+ /* Check for write access */
+ if (access(path, W_OK)) {
+ if (errno == EACCES) {
+ /*
+ * Do not treat this as an error since the permission
+ * might change in the lifetime of the process
+ */
+ DBG("Working directory \"%s\" is not writable", path);
+ } else {
+ PERROR("Failed to check if working directory \"%s\" is writable",
+ path);
+ }
+ }
+
+end:
+ return ret;
+}