lttng cli: Accept human readable sizes for --subbuf-size

[lttng-tools.git] / src / common / utils.c

diff --git a/src/common/utils.c b/src/common/utils.c
index 1c2b95d3e7d5d3e427bc4c20f59ba4483062dea9..f3718f00fa8ddabb7c921ac55287626dd83f45b8 100644 (file)
--- a/src/common/utils.c
+++ b/src/common/utils.c
@@ -26,6 +26,7 @@
 #include <sys/stat.h>
 #include <unistd.h>
 #include <inttypes.h>
+#include <regex.h>
 
 #include <common/common.h>
 #include <common/runas.h>
@@ -394,3 +395,126 @@ int utils_rotate_stream_file(char *path_name, char *file_name, uint64_t size,
 error:
        return ret;
 }
+
+/**
+ * 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.
+ */
+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(&regex, "^\\(0x\\)\\{0,1\\}[0-9][0-9]*\\([kKMG]\\{0,1\\}\\)$", 0);
+       if (ret != 0) {
+               regex_print_error(ret, &regex);
+               ret = -1;
+               goto end;
+       }
+
+       /* Match regex */
+       ret = regexec(&regex, 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(&regex);
+end:
+       return ret;
+}