From: Eric Wong <e@80x24.org>
To: mwrap-perl@80x24.org
Subject: [PATCH 1/3] support changing bt_req_depth dynamically
Date: Fri, 16 Dec 2022 14:39:31 +0000 [thread overview]
Message-ID: <20221216143933.22430-2-e@80x24.org> (raw)
In-Reply-To: <20221216143933.22430-1-e@80x24.org>
This is a valuable tuning knob and allows users to forgo
restarting an app to change backtrace depth. A /reset is
recommended.
---
Mwrap.xs | 16 ++++++++++++
httpd.h | 70 +++++++++++++++++++++++++++++++++++++++++++++-------
mwrap_core.h | 11 +++++----
t/httpd.t | 4 +++
t/mwrap.t | 8 ++++++
5 files changed, 95 insertions(+), 14 deletions(-)
diff --git a/Mwrap.xs b/Mwrap.xs
index 568ec2b..846d89d 100644
--- a/Mwrap.xs
+++ b/Mwrap.xs
@@ -132,6 +132,22 @@ mwrap_reset()
CODE:
mwrap_reset();
+unsigned
+mwrap_bt_depth(arg = &PL_sv_undef)
+ SV *arg;
+CODE:
+ if (SvOK(arg)) {
+ UV n = SvUVx(arg);
+ if (n > MWRAP_BT_MAX)
+ n = MWRAP_BT_MAX;
+ CMM_STORE_SHARED(bt_req_depth, (uint32_t)n);
+ RETVAL = n;
+ } else {
+ RETVAL = CMM_LOAD_SHARED(bt_req_depth);
+ }
+OUTPUT:
+ RETVAL
+
Devel::Mwrap::SrcLoc
mwrap_get(loc)
SV *loc;
diff --git a/httpd.h b/httpd.h
index 9b4ebe7..fc7b873 100644
--- a/httpd.h
+++ b/httpd.h
@@ -41,6 +41,7 @@
#define URL "https://80x24.org/mwrap-perl.git/about"
#define TYPE_HTML "text/html; charset=UTF-8"
#define TYPE_CSV "text/csv"
+#define TYPE_PLAIN "text/plain"
enum mw_qev {
MW_QEV_IGNORE = 0,
@@ -341,6 +342,15 @@ static enum mw_qev h1_do_trim(struct mw_h1 *h1)
return h1_res_oneshot(h1, r200, sizeof(r200) - 1);
}
+static enum mw_qev h1_do_ctl_finish(struct mw_h1 *h1)
+{
+ struct mw_fbuf plain;
+ FILE *fp = wbuf_init(&plain);
+ if (!fp) return h1_close(h1);
+ fprintf(fp, "MWRAP=bt:%u\n", (unsigned)CMM_LOAD_SHARED(bt_req_depth));
+ return h1_200(h1, &plain, TYPE_PLAIN);
+}
+
#define PATH_SKIP(h1r, pfx) path_skip(h1r, pfx, sizeof(pfx) - 1)
static const char *path_skip(struct mw_h1req *h1r, const char *pfx, size_t len)
{
@@ -570,7 +580,7 @@ static enum mw_qev each_at(struct mw_h1 *h1, struct mw_h1req *h1r)
FPUTS("<html><head><title>", fp);
write_html(fp, lb.ptr, lb.len);
FPUTS("</title></head><body><p>live allocations at:", fp);
- if (bt_req_depth) FPUTS("<br/>", fp);
+ if (l->bt_len > 1 || (l->bt_len == 1 && l->f)) FPUTS("<br/>", fp);
else fputc(' ', fp);
write_html(fp, lb.ptr, lb.len);
@@ -627,13 +637,14 @@ static enum mw_qev each_gt(struct mw_h1 *h1, struct mw_h1req *h1r,
if (!fp) return h1_close(h1);
if (!csv) {
+ unsigned depth = (unsigned)CMM_LOAD_SHARED(bt_req_depth);
fprintf(fp, "<html><head><title>mwrap each >%lu"
"</title></head><body><p>mwrap each >%lu "
"(change `%lu' in URL to adjust filtering) - "
- "MWRAP=bt:%u", min, min, min, (unsigned)bt_req_depth);
+ "MWRAP=bt:%u", min, min, min, depth);
show_stats(fp);
/* need borders to distinguish multi-level traces */
- if (bt_req_depth)
+ if (depth)
FPUTS("<table\nborder=1><tr>", fp);
else /* save screen space if only tracing one line */
FPUTS("<table><tr>", fp);
@@ -757,6 +768,8 @@ static enum mw_qev h1_dispatch(struct mw_h1 *h1, struct mw_h1req *h1r)
return h1_do_reset(h1);
if (h1r->path_len == 5 && !memcmp(h1r->path, "/trim", 5))
return h1_do_trim(h1);
+ if (h1r->path_len == 4 && !memcmp(h1r->path, "/ctl", 4))
+ return h1_do_ctl_finish(h1);
}
return h1_404(h1);
}
@@ -816,12 +829,31 @@ static enum mw_qev h1_drain_input(struct mw_h1 *h1, struct mw_h1req *h1r)
return h1_dispatch(h1, h1r);
}
+static bool valid_end(const char *end)
+{
+ switch (*end) {
+ case '\r': case ' ': case '\t': case '\n': return true;
+ default: return false;
+ }
+}
+
+/* no error reporting, too much code */
+static void ctl_set(struct mw_h1 *h1, long n)
+{
+ if (n >= 0) {
+ if (n > MWRAP_BT_MAX)
+ n = MWRAP_BT_MAX;
+ CMM_STORE_SHARED(bt_req_depth, (uint32_t)n);
+ }
+}
+
static enum mw_qev h1_parse_harder(struct mw_h1 *h1, struct mw_h1req *h1r)
{
enum { HDR_IGN, HDR_CONN, HDR_XENC, HDR_CLEN } cur = HDR_IGN;
bool conn_set = false;
char *end;
struct phr_header *hdr = h1r->hdr;
+ long depth = -1;
h1->prev_len = 0;
h1->has_input = 0;
@@ -837,8 +869,21 @@ static enum mw_qev h1_parse_harder(struct mw_h1 *h1, struct mw_h1req *h1r)
cur = HDR_CONN;
else if (NAME_EQ(hdr, "Trailer"))
return h1_400(h1);
- else if (hdr->name)
+ else if (hdr->name) {
cur = HDR_IGN;
+ /*
+ * don't want to increase code to deal with POST
+ * request bodies, so let pico handle parameters in
+ * HTTP request headers, instead.
+ */
+ if (NAME_EQ(hdr, "X-Mwrap-BT-Depth")) {
+ errno = 0;
+ depth = strtol(hdr->value, &end, 10);
+ if (errno || !valid_end(end))
+ depth = -1;
+ }
+ }
+
/* else: continuation line */
if (!hdr->value_len)
continue;
@@ -860,12 +905,8 @@ static enum mw_qev h1_parse_harder(struct mw_h1 *h1, struct mw_h1req *h1r)
h1->has_input = 1;
errno = 0;
h1->in_len = strtoul(hdr->value, &end, 10);
- if (errno)
+ if (errno || !valid_end(end))
return h1_400(h1);
- switch (*end) {
- case '\r': case ' ': case '\t': case '\n': break;
- default: return h1_400(h1);
- }
break;
case HDR_IGN:
break;
@@ -883,6 +924,17 @@ static enum mw_qev h1_parse_harder(struct mw_h1 *h1, struct mw_h1req *h1r)
} else {
return h1_404(h1);
}
+
+ /*
+ * special case for /ctl, since I don't feel like parsing queries
+ * in the request body (ensure no query string, too)
+ */
+ if (h1r->method_len == 4 && !memcmp(h1r->method, "POST", 4)) {
+ if (h1r->path_len == 4 && !memcmp(h1r->path, "/ctl", 4))
+ ctl_set(h1, depth);
+ }
+
+ /* break off QUERY_STRING */
h1r->qstr = memchr(h1r->path, '?', h1r->path_len);
if (h1r->qstr) {
++h1r->qstr; /* ignore '?' */
diff --git a/mwrap_core.h b/mwrap_core.h
index 3fd67f1..9e4f065 100644
--- a/mwrap_core.h
+++ b/mwrap_core.h
@@ -13,6 +13,7 @@
typedef void COP;
#endif
+/* set a sensible max to avoid stack overflows */
#ifndef MWRAP_BT_MAX
# define MWRAP_BT_MAX 32
#endif
@@ -136,14 +137,14 @@ static void *my_mempcpy(void *dest, const void *src, size_t n)
#define SRC_LOC_BT(bt) union stk_bt bt; do { \
- uint32_t depth = locating ? 1 : bt_req_depth; \
+ uint32_t depth = locating ? 1 : CMM_LOAD_SHARED(bt_req_depth); \
switch (depth) { \
case 0: \
case 1: bt.sl.bt_len = 1; bt.sl.bt[0] = RETURN_ADDRESS(0); break; \
default: /* skip 1st level of BT since thats our function */ \
- mwrap_assert(bt_req_depth <= MWRAP_BT_MAX); \
+ mwrap_assert(depth <= MWRAP_BT_MAX); \
++locating; \
- long n = (long)backtrace(bt_dst(&bt), bt_req_depth); \
+ long n = (long)backtrace(bt_dst(&bt), depth); \
--locating; \
bt.sl.bt_len = n <= 1 ? 0 : (uint32_t)n - 1; \
if (n > 1) mwrap_assert(bt.sl.bt[0] == RETURN_ADDRESS(0)); \
@@ -1026,9 +1027,9 @@ __attribute__((constructor)) static void mwrap_ctor(void)
char *end;
unsigned long n = strtoul(bt, &end, 10);
if (n && !errno && (*end == ',' || *end == 0)) {
- if (n >= MWRAP_BT_MAX)
+ if (n > MWRAP_BT_MAX)
n = MWRAP_BT_MAX;
- bt_req_depth = (uint32_t)n;
+ CMM_STORE_SHARED(bt_req_depth, (uint32_t)n);
}
}
}
diff --git a/t/httpd.t b/t/httpd.t
index 176c6ed..3fe9c1f 100644
--- a/t/httpd.t
+++ b/t/httpd.t
@@ -157,6 +157,10 @@ SKIP: {
$rc = system(qw(curl -vsSf --unix-socket), $sock, '-o', $cout,
'-d', 'x=y', "http://0/$pid/reset");
is($rc, 0, 'curl /reset');
+ $rc = system(qw(curl -vsSf --unix-socket), $sock, '-o', $cout,
+ '-HX-Mwrap-BT-Depth:10', '-XPOST', "http://0/$pid/ctl");
+ is($rc, 0, 'curl /ctl (X-Mwrap-BT-Depth)');
+ like(slurp($cout), qr/\bMWRAP=bt:10\b/, 'changed bt depth');
};
diff --git a/t/mwrap.t b/t/mwrap.t
index bf6ae6e..76a2366 100644
--- a/t/mwrap.t
+++ b/t/mwrap.t
@@ -166,4 +166,12 @@ EOM
'aligned_alloc + cfree function ran w/o crashing');
};
+is(Devel::Mwrap::bt_depth(), 0, 'default bt depth is zero');
+is(Devel::Mwrap::bt_depth(5), 5, 'set depth to reasonable level');
+is(Devel::Mwrap::bt_depth(), 5, 'depth stays at 5');
+is(Devel::Mwrap::bt_depth(500), 32, 'depth clamped to 32 when 500 attempted');
+is(Devel::Mwrap::bt_depth(), 32, 'depth stayed clamped at 32');
+is(Devel::Mwrap::bt_depth(undef), 32, 'depth stayed clamped at 32');
+is(Devel::Mwrap::bt_depth(-1), 32, 'depth stayed clamped at 32');
+
done_testing;
next prev parent reply other threads:[~2022-12-16 14:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-16 14:39 [PATCH 0/3] fleshing out some things Eric Wong
2022-12-16 14:39 ` Eric Wong [this message]
2022-12-16 14:39 ` [PATCH 2/3] support symlink install Eric Wong
2022-12-16 14:39 ` [PATCH 3/3] various documentation updates Eric Wong
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