Messages in this thread Patch in this message | | | Date | Tue, 31 Aug 2004 12:25:59 -0700 | From | William Lee Irwin III <> | Subject | Re: [util-linux] readprofile ignores the last element in /proc/profile |
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On Monday 30 August 2004 01:22, William Lee Irwin III wrote: >> Well, since I couldn't stop vomiting for hours after I looked at the >> code for readprofile(1), here's a reimplementation, with various >> misfeatures removed, included as a MIME attachment.
On Wed, Sep 01, 2004 at 01:45:51AM +0900, mita akinobu wrote: > The rewritten readprofile still ignores the last element on my machine. > Boot option: > profile=2 > System.map: > c0100264 t ignore_int > c0100298 T _stext > c0100298 T calibrate_delay > [...] > c03acbf1 T __spinlock_text_end > c03ae0af A _etext > c03ae0b0 A __start___ex_table
It can't find anything outside a symbol in System.map, as it's iterating over symbols in System.map. Special treatment for the final profile buffer position is likely in order.
On Wed, Sep 01, 2004 at 01:45:51AM +0900, mita akinobu wrote: > This is quick fix. > --- readprofile.c.orig 2004-08-31 23:01:23.000000000 +0900 > +++ readprofile.c 2004-09-01 01:39:00.316750264 +0900 > @@ -25,6 +25,7 @@ struct profile_state { > int fd, shift; > uint32_t *buf; > size_t bufsz; > + size_t bufcnt; > struct sym syms[2], *last, *this; > unsigned long long stext, vaddr; > unsigned long total; > @@ -101,8 +102,8 @@ static int state_transition(struct profi > exit(EXIT_FAILURE); > } > } > - if (read(state->fd, state->buf, end - start) == end - start) { > - for (off = 0; off < (end - start)/sizeof(uint32_t); ++off) > + if ((state->bufcnt = read(state->fd, state->buf, end - start)) >= 0) { > + for (off = 0; off < (state->bufcnt)/sizeof(uint32_t); ++off) > state->last->hits += state->buf[off]; > } else { > ret = 1;
So the last read is always short, which is irritating; but bufcnt needs to be ssize_t or the nonnegativity condition can never fail. Otherwise it will report bogus results or terminate in a disorderly fashion if the read() fails outright, e.g. running out of memory or interruption by signals. So I propose the following alternative patch.
-- wli
--- readprofile.c.orig2 2004-08-31 12:11:54.000000000 -0700 +++ readprofile.c 2004-08-31 12:13:44.000000000 -0700 @@ -65,6 +65,7 @@ int ret = 0; long page_mask, start, end; unsigned off; + ssize_t bufcnt; if (!state->stext) { if (!strcmp(state->sym, "_stext")) @@ -101,8 +102,8 @@ exit(EXIT_FAILURE); } } - if (read(state->fd, state->buf, end - start) == end - start) { - for (off = 0; off < (end - start)/sizeof(uint32_t); ++off) + if ((bufcnt = read(state->fd, state->buf, end - start)) >= 0) { + for (off = 0; off < bufcnt/sizeof(uint32_t); ++off) state->last->hits += state->buf[off]; } else { ret = 1; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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