Re: [PATCH 1/2] perf tool: Refactor comm/tgid lookup

From: Jiri Olsa
Date: Mon Mar 30 2015 - 04:01:39 EST


On Sun, Mar 29, 2015 at 04:30:01PM -0600, David Ahern wrote:

SNIP

> + fd = open(filename, O_RDONLY);
> + if (fd < 0) {
> pr_debug("couldn't open %s\n", filename);
> return 0;
> }
>
> - while (!comm[0] || (tgid < 0)) {
> - if (fgets(bf, sizeof(bf), fp) == NULL) {
> - pr_warning("couldn't get COMM and pgid, malformed %s\n",
> - filename);
> - break;
> - }
> -
> - if (memcmp(bf, "Name:", 5) == 0) {
> - char *name = bf + 5;
> - while (*name && isspace(*name))
> - ++name;
> - size = strlen(name) - 1;
> - if (size >= len)
> - size = len - 1;
> - memcpy(comm, name, size);
> - comm[size] = '\0';
> -
> - } else if (memcmp(bf, "Tgid:", 5) == 0) {
> - char *tgids = bf + 5;
> - while (*tgids && isspace(*tgids))
> - ++tgids;
> - tgid = atoi(tgids);
> - }
> + n = read(fd, bf, sizeof(bf) - 1);
> + close(fd);

we have filename__read_str, which will read whole file into buffer,
and you dont need to worry about the file size.. not that there's
any worry wrt /proc/<pid>/status file, but who knows.. ;-)

jirka
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