+
+/**
+ * Prints the error message corresponding to a regex error code.
+ *
+ * @param errcode The error code.
+ * @param regex The regex object that produced the error code.
+ */
+static void regex_print_error(int errcode, regex_t *regex)
+{
+ /* Get length of error message and allocate accordingly */
+ size_t length;
+ char *buffer;
+
+ assert(regex != NULL);
+
+ length = regerror(errcode, regex, NULL, 0);
+ if (length == 0) {
+ ERR("regerror returned a length of 0");
+ return;
+ }
+
+ buffer = zmalloc(length);
+ if (!buffer) {
+ ERR("regex_print_error: zmalloc failed");
+ return;
+ }
+
+ /* Get and print error message */
+ regerror(errcode, regex, buffer, length);
+ ERR("regex error: %s\n", buffer);
+ free(buffer);
+
+}
+
+/**
+ * Parse a string that represents a size in human readable format. It
+ * supports decimal integers suffixed by '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 size_t that will be filled with the
+ * resulting size.
+ *
+ * @return 0 on success, -1 on failure.
+ */
+LTTNG_HIDDEN
+int utils_parse_size_suffix(char *str, uint64_t *size)
+{
+ regex_t regex;
+ int ret;
+ const int nmatch = 3;
+ regmatch_t suffix_match, matches[nmatch];
+ unsigned long long base_size;
+ long shift = 0;
+
+ if (!str) {
+ return 0;
+ }
+
+ /* Compile regex */
+ ret = regcomp(®ex, "^\\(0x\\)\\{0,1\\}[0-9][0-9]*\\([kKMG]\\{0,1\\}\\)$", 0);
+ if (ret != 0) {
+ regex_print_error(ret, ®ex);
+ ret = -1;
+ goto end;
+ }
+
+ /* Match regex */
+ ret = regexec(®ex, str, nmatch, matches, 0);
+ if (ret != 0) {
+ ret = -1;
+ goto free;
+ }
+
+ /* There is a match ! */
+ errno = 0;
+ base_size = strtoull(str, NULL, 0);
+ if (errno != 0) {
+ PERROR("strtoull");
+ ret = -1;
+ goto free;
+ }
+
+ /* Check if there is a suffix */
+ suffix_match = matches[2];
+ if (suffix_match.rm_eo - suffix_match.rm_so == 1) {
+ switch (*(str + suffix_match.rm_so)) {
+ case 'K':
+ case 'k':
+ shift = KIBI_LOG2;
+ break;
+ case 'M':
+ shift = MEBI_LOG2;
+ break;
+ case 'G':
+ shift = GIBI_LOG2;
+ break;
+ default:
+ ERR("parse_human_size: invalid suffix");
+ ret = -1;
+ goto free;
+ }
+ }
+
+ *size = base_size << shift;
+
+ /* Check for overflow */
+ if ((*size >> shift) != base_size) {
+ ERR("parse_size_suffix: oops, overflow detected.");
+ ret = -1;
+ goto free;
+ }
+
+ ret = 0;
+
+free:
+ regfree(®ex);
+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
+
+#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);
+}
+
+/**
+ * Obtain the value of LTTNG_HOME environment variable, if exists.
+ * Otherwise returns the value of HOME.
+ */
+LTTNG_HIDDEN
+char *utils_get_home_dir(void)
+{
+ char *val = NULL;
+ val = getenv(DEFAULT_LTTNG_HOME_ENV_VAR);
+ if (val != NULL) {
+ return val;
+ }
+ return getenv(DEFAULT_LTTNG_FALLBACK_HOME_ENV_VAR);
+}
+
+/*
+ * 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 %lu", format,
+ dst, len);
+ }
+
+ return ret;
+}
+
+/*
+ * Return the group ID matching name, else 0 if it cannot be found.
+ */
+LTTNG_HIDDEN
+gid_t utils_get_group_id(const char *name)
+{
+ struct group *grp;
+
+ grp = getgrnam(name);
+ if (!grp) {
+ static volatile int warn_once;
+
+ if (!warn_once) {
+ WARN("No tracing group detected");
+ warn_once = 1;
+ }
+ return 0;
+ }
+ return grp->gr_gid;
+}
+
+/*
+ * 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;
+ }
+
+ optstring[str_pos++] = (char)long_options[i].val;
+ if (long_options[i].has_arg) {
+ optstring[str_pos++] = ':';
+ }
+ }
+
+end:
+ return optstring;
+}