Date: Sun, 17 Aug 2008 17:17:54 +0000 From: "Guillaume Ballet" <gballet@gmail.com> To: "Sam Leffler" <sam@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: Extending the ddb command set Message-ID: <fd183dc60808171017m7eabcef2xbe1845e54cda4c99@mail.gmail.com> In-Reply-To: <48A70B37.60401@freebsd.org> References: <fd183dc60808160203r3d90c26dq4d282d2ef153d2db@mail.gmail.com> <48A70B37.60401@freebsd.org>
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On Sat, Aug 16, 2008 at 5:15 PM, Sam Leffler <sam@freebsd.org> wrote: > > Guillaume Ballet wrote: >> >> Hello hackers, >> >> I am currently working on a small project and would like to add a few >> commands to the set that is available in ddb. >> >> I found that very interesting albeit succinct presentation: >> http://people.freebsd.org/~jhb/papers/bsdcan/2008/slides.odp<http://people.freebsd.org/%7Ejhb/papers/bsdcan/2008/slides.odp>; >> >> where the author hints that I should use DB_COMMAND, which I did. Yet when >> invoking ddb, the command does not appear in the help list. I have taken a >> look at the source code and was expecting set_db_cmd_set to appear in my >> module's section list when calling objdump -h >> >> Is DB_COMMAND only working within the kernel itself, and not modules? >> >> > > That is correct; you can't add ddb cmds from modules. It should be doable; just hasn't been done yet. > > Sam > It is indeed doable: Here are the diffs for a first attempt at doing this. I am not entirely satisfied with it, though, as it does not work with DB_SHOW_COMMAND and the likes... Also, I have to declare a lot of ddb-related stuff into kern_linker.c and I don't like it. I am currently working at improving the whole thing, but in the mean time if someone wants to give it a try, comments/rants would be greatly appreciated. Guillaume --- sys/linker.h.orig 2008-08-17 18:45:56.000000000 +0200 +++ sys/linker.h 2008-08-17 18:50:57.000000000 +0200 @@ -155,6 +155,9 @@ int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym, long *_diffp); int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval); +struct command; +int linker_ddb_cmd_search(char *, struct command **); +int linker_ddb_cmd_list(void); /* HWPMC helper */ --- kern/kern_linker.c.orig 2008-08-17 08:38:51.000000000 +0200 +++ kern/kern_linker.c 2008-08-17 18:47:45.000000000 +0200 @@ -777,6 +777,9 @@ * that the files list is inconsistant instead. */ +#include <ddb/ddb.h> +#include <ddb/db_output.h> + int linker_ddb_lookup(const char *symstr, c_linker_sym_t *sym) { @@ -831,6 +834,52 @@ } return (ENOENT); } + +int linker_ddb_cmd_list() +{ + linker_file_t lf; + struct command **start, **stop, **search; + + TAILQ_FOREACH(lf, &linker_files, link) { + if (!linker_file_lookup_set(lf,"db_cmd_set",&start,&stop,NULL)) { + for (search=start; search < stop; search++) { + db_printf("%-12s", (*search)->name); + db_end_line(12); + } + } + } + + return 0; +} + +int linker_ddb_cmd_search(char *name, struct command **cmdp) +{ + linker_file_t lf; + char *lp, *rp; + struct command **cmd, **start, **stop; + int c; + + TAILQ_FOREACH(lf, &linker_files, link) { + if (!linker_file_lookup_set(lf, "db_cmd_set", &start, &stop, NULL)) { + for (cmd=start; cmd < stop; cmd++) { + lp = name; + rp = (*cmd)->name; + + while((c = *lp) == *rp) { + if (c == 0) { + *cmdp = *cmd; + return 0; + } + + lp++; + rp++; + } + } + } + } + + return -1; +} #endif /* --- ddb/db_command.c.orig 2008-08-17 10:26:26.000000000 +0200 +++ ddb/db_command.c 2008-08-17 18:42:22.000000000 +0200 @@ -253,6 +253,9 @@ if (result == CMD_UNIQUE) return (CMD_UNIQUE); } + if (result == CMD_NONE && linker_ddb_cmd_search(name,cmdp) == 0) { + result = CMD_UNIQUE; + } if (result == CMD_NONE) { /* check for 'help' */ if (name[0] == 'h' && name[1] == 'e' @@ -280,6 +283,7 @@ db_printf("%-12s", (*aux_cmdp)->name); db_end_line(12); } + linker_ddb_cmd_list(); } static void --- ddb/db_command.h.orig 2008-08-17 18:37:34.000000000 +0200 +++ ddb/db_command.h 2008-08-17 18:49:29.000000000 +0200 @@ -46,4 +46,7 @@ extern db_addr_t db_next; /* next address to be examined or written */ +extern int linker_ddb_cmd_search(char*,struct command **); +extern int linker_ddb_cmd_list(void); + #endif /* !_DDB_DB_COMMAND_H_ */
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