From 051cdc3c2d0e24443ac03aff03ee89807ec8c589 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 3 Jun 2009 20:09:11 +0200 Subject: [PATCH] perf help: Fix bug when there's no perf-* command around main_cmds can be empty - fix util/help.c to handle this case without segfaulting. Reported-by: Steven Rostedt Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Corey Ashford Cc: Marcelo Tosatti Cc: Arnaldo Carvalho de Melo Cc: Thomas Gleixner LKML-Reference: Signed-off-by: Ingo Molnar --- Documentation/perf_counter/util/help.c | 28 +++++++++++++++----------- 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/Documentation/perf_counter/util/help.c b/Documentation/perf_counter/util/help.c index 397487fb2bee..6653f7dd1d78 100644 --- a/Documentation/perf_counter/util/help.c +++ b/Documentation/perf_counter/util/help.c @@ -298,7 +298,7 @@ static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old) const char *help_unknown_cmd(const char *cmd) { - int i, n, best_similarity = 0; + int i, n = 0, best_similarity = 0; struct cmdnames main_cmds, other_cmds; memset(&main_cmds, 0, sizeof(main_cmds)); @@ -315,20 +315,24 @@ const char *help_unknown_cmd(const char *cmd) sizeof(main_cmds.names), cmdname_compare); uniq(&main_cmds); - /* This reuses cmdname->len for similarity index */ - for (i = 0; i < main_cmds.cnt; ++i) - main_cmds.names[i]->len = - levenshtein(cmd, main_cmds.names[i]->name, 0, 2, 1, 4); + if (main_cmds.cnt) { + /* This reuses cmdname->len for similarity index */ + for (i = 0; i < main_cmds.cnt; ++i) + main_cmds.names[i]->len = + levenshtein(cmd, main_cmds.names[i]->name, 0, 2, 1, 4); - qsort(main_cmds.names, main_cmds.cnt, - sizeof(*main_cmds.names), levenshtein_compare); + qsort(main_cmds.names, main_cmds.cnt, + sizeof(*main_cmds.names), levenshtein_compare); + + best_similarity = main_cmds.names[0]->len; + n = 1; + while (n < main_cmds.cnt && best_similarity == main_cmds.names[n]->len) + ++n; + } - best_similarity = main_cmds.names[0]->len; - n = 1; - while (n < main_cmds.cnt && best_similarity == main_cmds.names[n]->len) - ++n; if (autocorrect && n == 1) { const char *assumed = main_cmds.names[0]->name; + main_cmds.names[0] = NULL; clean_cmdnames(&main_cmds); fprintf(stderr, "WARNING: You called a Git program named '%s', " @@ -345,7 +349,7 @@ const char *help_unknown_cmd(const char *cmd) fprintf(stderr, "perf: '%s' is not a perf-command. See 'perf --help'.\n", cmd); - if (best_similarity < 6) { + if (main_cmds.cnt && best_similarity < 6) { fprintf(stderr, "\nDid you mean %s?\n", n < 2 ? "this": "one of these"); -- 2.20.1