Re: JDK-8211343: nsk_jvmti_parseoptions should handle multiple suboptions

[Chris Plummer]

Wow, the existing comments for this function take a lot of work to translate. You basically need to understand the code in order to understand the comment. Kind of backwards. Below I've included all the existing code and comments, with my translation of the comments and also additional annotations. But before getting into that, I think the proposed fix is just working around all the bugs elsewhere in the function by making opt point to a string that just contains the current option we are working on, rather than attempting (poorly and incorrectly) to point to the next option within the options string. Although tokenizing the string in this way is probably the better approach, it would be nice to at the same time clean up all the other errors and comments in this code. /**  *  * The current option will not perform more than one  * single option which given, this is due to places explained  * in this question.  *  **/ # This current implementation will not parse more than one option. The # reason is explained in comments below.  /*   * This whole play can be reduced with simple StringTokenizer (strtok).   *   */ # This function can be simplified by using strok(). int nsk_jvmti_parseOptions(const char options[]) {     size_t len;     const char* opt;     int success = NSK_TRUE;     context.options.string = NULL;     context.options.count = 0;     context.waittime = 2;     if (options == NULL)         return NSK_TRUE;     len = strlen(options);     context.options.string = (char*)malloc(len + 2);     if (context.options.string == NULL) {             nsk_complain("nsk_jvmti_parseOptions(): out of memory\n");             return NSK_FALSE;     }     strncpy(context.options.string, options, len);     context.options.string[len] = '\0';     context.options.string[len+1] = '\0';     for (opt = context.options.string; ;) {         const char* opt_end;         const char* val_sep;         int opt_len=0;         int val_len=0;         int exit=1;         while (*opt != '\0' && isOptSep(*opt)) opt++;         if (*opt == '\0') break;         val_sep = NULL;         /*             This should break when the first option it encounters other wise         */ # This should break at the end of the first option, before the option value is specified # if there is an option value.         for (opt_end = opt, opt_len=0; !(*opt_end == '\0' || isOptSep(*opt_end)); opt_end++,opt_len++) {             if (*opt_end == NSK_JVMTI_OPTION_VAL_SEP) {                 val_sep = opt_end;                 exit=0;                 break;             }         }         if (exit == 1) break;         /* now scan for the search  for the option value end.         */ # Now scan for the end of the option value. [Chris: This is a bug because it assumes that there is a value. If we stopped in the above loop due to finding the option separator (which also seems to be broken), then we start reading the next option as the option value.]         exit =1;         opt_end++;         val_sep++;         /**          * I was expecting this jvmti_parseOptions(),          * should be for multiple options as well.          * If this break is not there then It will expects          * to have. so a space should be sufficient as well.          */ # I was expecting that nsk_jvmti_parseOptions() would parse multiple options. [Chris: I have no idea what the rest of the comment means. Due to the bug above with handling an option with no value, the code below doesn't do what was expected. The commented out part of it tried to do the right thing by searching for the '-' for the next option, whichis wrong because options don't begin with a '\'. They are separated by a comma, although the code elsewhere wants them separated by a space or a `~`.]         for (val_len=0; !(*opt_end == '\0' || isOptSep(*opt_end)); opt_end++,val_len++) {             //if (*opt_end == NSK_JVMTI_OPTION_START) {             //    break;             //}         }         if (!add_option(opt, opt_len, val_sep, val_len)) {             success = NSK_FALSE;             break;         }         opt_end++;         opt = opt_end;     } On 12/20/18 8:33 AM, Gary Adams wrote: I prototyped with strsep, because strtok is not safe and did not want to deal with the strtok_r versus strtok_s (windows) platform variants. ... #include <stdio.h> #include <string.h> int  main(int argc, char **argv){   char *str = strdup("waittime=5,verbose foo bar baz=11");   char *name;   char *value;   while ((name = strsep (&str, " ,")) != NULL) {     value = index(name, '=');         if (value == NULL) {       printf ("%s\n", name);     } else {       *value++ = '\0';       printf ("%s=%s\n", name, value);     }   } ... ./main waittime=5 verbose foo bar baz=11 On 12/20/18, 10:54 AM, JC Beyler wrote: Hi Gary, I had seen that too and forgot to file it! So thanks! I think the comment you removed is interesting, I'm not sure what it means exactly and I've tried re-reading a few times but the use of "in this question"  is weird :-) Anyway, the webrev looks good except perhaps for the use of strsep, which is BSD, instead of strtok, which is C89/C99/Posix. Thanks for doing this! Jc On Thu, Dec 20, 2018 at 5:17 AM Gary Adams <gary.ad...@oracle.com> wrote: During some earlier jvmti test debugging, I noticed that it was not possible to add a quick argument to the current tests and rerun the test. e.g. expand "waittime=5" to "waittime=5,verbose". I tracked down the options parsing in jvmti_tools.cpp and saw some comments that only a single option could be parsed. So I filed this bug to revisit the issue for the next release:    Issue: https://bugs.openjdk.java.net/browse/JDK-8211343 I think the option parsing should be ripped out and redone, but for now I think a simple tweak to use strsep(), might go a long way to solving the multiple option support. I just started testing, but wanted to know if anyone else has been down this rabbit hole before. diff --git a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp --- a/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp +++ b/test/hotspot/jtreg/vmTestbase/nsk/share/jvmti/jvmti_tools.cpp @@ -196,22 +196,14 @@   } -/** - * - * The current option will not perform more than one - * single option which given, this is due to places explained - * in this question. - * - **/ -    /* -  * This whole play can be reduced with simple StringTokenizer (strtok). -  * +   * Parse a comma or space separated list of options.     */   int nsk_jvmti_parseOptions(const char options[]) {       size_t len;       const char* opt; +    char *str = strdup(options);       int success = NSK_TRUE;       context.options.string = NULL; @@ -232,7 +224,7 @@       context.options.string[len] = '\0';       context.options.string[len+1] = '\0'; -    for (opt = context.options.string; ;) { +    while ((opt = strsep(&str, " ,")) != NULL) {           const char* opt_end;           const char* val_sep;           int opt_len=0; -- Thanks, Jc