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Pro1/2 usb-fix.c - parse path on newer kernels #68

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Pro1/2 usb-fix.c - parse path on newer kernels #68

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32 changes: 26 additions & 6 deletions src/main/hook/propatch/usb-fix.c
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#define LOG_MODULE "usb-fix"

#include <ctype.h>
#include <unistd.h>

#include "capnhook/hook/lib.h"
Expand Down Expand Up @@ -69,9 +70,12 @@ ssize_t propatch_usb_fix_readlink(const char *path, char *buf, size_t len)

toks = util_str_split(buf, "/", &count);

log_debug("Parsing USB device path with %zu tokens", count);

// some sanity checks to ensure the format isn't different
if (count != 12 || strcmp(toks[0], "..") != 0 ||
strcmp(toks[1], "devices") != 0 || strcmp(toks[10], "block") != 0) {
// The format can vary between 12 and 13 tokens depending on USB hierarchy depth
if (count < 12 || count > 13 || strcmp(toks[0], "..") != 0 ||
strcmp(toks[1], "devices") != 0 || strcmp(toks[count-2], "block") != 0) {
log_error(
"/sys/block device readlink format changed, usb thumb drive "
"profiles will likely not work!: %s",
Expand All @@ -82,10 +86,26 @@ ssize_t propatch_usb_fix_readlink(const char *path, char *buf, size_t len)

int bus;
int port;
const char *device = toks[11];

if (sscanf(toks[5], "%d-%d", &bus, &port) != 2) {
log_error("Parsing bus-port of %s failed", buf);
const char *device = toks[count-1];

// Find the USB device identifier token (format: X-Y or X-Y.Z or X-Y.Z.W etc.)
// It should be one of the tokens that starts with a digit and contains a dash
bool found_usb_id = false;
for (size_t i = 4; i < count - 3; i++) { // Skip initial path components and final ones
if (isdigit(toks[i][0]) && strchr(toks[i], '-')) {
log_debug("Checking USB identifier token[%zu]: %s", i, toks[i]);
// Try to parse the main bus-port from this token
char *dash_pos = strchr(toks[i], '-');
if (dash_pos && sscanf(toks[i], "%d-%d", &bus, &port) == 2) {
log_debug("Successfully parsed USB bus %d, port %d from token: %s", bus, port, toks[i]);
found_usb_id = true;
break;
}
}
}

if (!found_usb_id) {
log_error("Could not find valid USB bus-port identifier in path: %s", buf);
util_str_free_split(toks, count);
return 0;
}
Expand Down