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fix: improve error handling of snprintf() in send_thread_stop_status() #4234

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Merged
lum1n0us merged 1 commit into from
May 9, 2025
Merged

fix: improve error handling of snprintf() in send_thread_stop_status() #4234

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81 changes: 57 additions & 24 deletions core/iwasm/libraries/debug-engine/handler.c
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Original file line number Diff line number Diff line change
Expand Up @@ -383,7 +383,7 @@ send_thread_stop_status(WASMGDBServer *server, uint32 status, korp_tid tid)

if (status == 0) {
os_mutex_lock(&tmpbuf_lock);
snprintf(tmpbuf, MAX_PACKET_SIZE, "W%02" PRIx32, status);
(void)snprintf(tmpbuf, MAX_PACKET_SIZE, "W%02" PRIx32, status);
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write_packet(server, tmpbuf);
os_mutex_unlock(&tmpbuf_lock);
return;
Expand All @@ -399,18 +399,38 @@ send_thread_stop_status(WASMGDBServer *server, uint32 status, korp_tid tid)

os_mutex_lock(&tmpbuf_lock);
// TODO: how name a wasm thread?
len += snprintf(tmpbuf, MAX_PACKET_SIZE,
"T%02" PRIx32 "thread:%" PRIx64 ";name:%s;", gdb_status,
(uint64)(uintptr_t)tid, "nobody");
len = snprintf(tmpbuf, MAX_PACKET_SIZE,
"T%02" PRIx32 "thread:%" PRIx64 ";name:%s;", gdb_status,
(uint64)(uintptr_t)tid, "nobody");
if (len < 0 || len >= MAX_PACKET_SIZE) {
os_mutex_unlock(&tmpbuf_lock);
return;
}

if (tids_count > 0) {
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len, "threads:");
int n = snprintf(tmpbuf + len, MAX_PACKET_SIZE - len, "threads:");
if (n < 0 || n >= MAX_PACKET_SIZE - len) {
os_mutex_unlock(&tmpbuf_lock);
return;
}

len += n;
while (i < tids_count) {
if (i == tids_count - 1)
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"%" PRIx64 ";", (uint64)(uintptr_t)tids[i]);
else
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"%" PRIx64 ",", (uint64)(uintptr_t)tids[i]);
if (i == tids_count - 1) {
n = snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"%" PRIx64 ";", (uint64)(uintptr_t)tids[i]);
}
else {
n = snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"%" PRIx64 ",", (uint64)(uintptr_t)tids[i]);
}

if (n < 0 || n >= MAX_PACKET_SIZE - len) {
os_mutex_unlock(&tmpbuf_lock);
return;
}

len += n;
i++;
}
}
Expand All @@ -427,32 +447,45 @@ send_thread_stop_status(WASMGDBServer *server, uint32 status, korp_tid tid)
/* When exception occurs, use reason:exception so the description can be
* correctly processed by LLDB */
uint32 exception_len = strlen(exception);
len +=
int n =
snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;description:", pc,
pc_string, "exception");
if (n < 0 || n >= MAX_PACKET_SIZE - len) {
os_mutex_unlock(&tmpbuf_lock);
return;
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}

len += n;
/* The description should be encoded as HEX */
for (i = 0; i < exception_len; i++) {
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len, "%02x",
exception[i]);
n = snprintf(tmpbuf + len, MAX_PACKET_SIZE - len, "%02x",
exception[i]);
if (n < 0 || n >= MAX_PACKET_SIZE - len) {
os_mutex_unlock(&tmpbuf_lock);
return;
}

len += n;
}
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len, ";");

(void)snprintf(tmpbuf + len, MAX_PACKET_SIZE - len, ";");
}
else {
if (status == WAMR_SIG_TRAP) {
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;", pc,
pc_string, "breakpoint");
(void)snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;", pc,
pc_string, "breakpoint");
}
else if (status == WAMR_SIG_SINGSTEP) {
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;", pc,
pc_string, "trace");
(void)snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;", pc,
pc_string, "trace");
}
else { /* status > 0 (== 0 is checked at the function beginning) */
len += snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;", pc,
pc_string, "signal");
(void)snprintf(tmpbuf + len, MAX_PACKET_SIZE - len,
"thread-pcs:%" PRIx64 ";00:%s;reason:%s;", pc,
pc_string, "signal");
}
}
write_packet(server, tmpbuf);
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