1.1 --- a/src/os/linux/vm/os_linux.cpp Mon Mar 28 12:48:08 2011 +0200
1.2 +++ b/src/os/linux/vm/os_linux.cpp Wed Mar 30 19:38:07 2011 +0400
1.3 @@ -2648,45 +2648,39 @@
1.4 // writing thread stacks don't use growable mappings (i.e. those
1.5 // creeated with MAP_GROWSDOWN), and aren't marked "[stack]", so this
1.6 // only applies to the main thread.
1.7 -static bool
1.8 -get_stack_bounds(uintptr_t *bottom, uintptr_t *top)
1.9 -{
1.10 - FILE *f = fopen("/proc/self/maps", "r");
1.11 - if (f == NULL)
1.12 +
1.13 +static
1.14 +bool get_stack_bounds(uintptr_t *bottom, uintptr_t *top) {
1.15 +
1.16 + char buf[128];
1.17 + int fd, sz;
1.18 +
1.19 + if ((fd = ::open("/proc/self/maps", O_RDONLY)) < 0) {
1.20 return false;
1.21 -
1.22 - while (!feof(f)) {
1.23 - size_t dummy;
1.24 - char *str = NULL;
1.25 - ssize_t len = getline(&str, &dummy, f);
1.26 - if (len == -1) {
1.27 - fclose(f);
1.28 - return false;
1.29 - }
1.30 -
1.31 - if (len > 0 && str[len-1] == '\n') {
1.32 - str[len-1] = 0;
1.33 - len--;
1.34 - }
1.35 -
1.36 - static const char *stack_str = "[stack]";
1.37 - if (len > (ssize_t)strlen(stack_str)
1.38 - && (strcmp(str + len - strlen(stack_str), stack_str) == 0)) {
1.39 - if (sscanf(str, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
1.40 - uintptr_t sp = (uintptr_t)__builtin_frame_address(0);
1.41 - if (sp >= *bottom && sp <= *top) {
1.42 - free(str);
1.43 - fclose(f);
1.44 - return true;
1.45 + }
1.46 +
1.47 + const char kw[] = "[stack]";
1.48 + const int kwlen = sizeof(kw)-1;
1.49 +
1.50 + // Address part of /proc/self/maps couldn't be more than 128 bytes
1.51 + while ((sz = os::get_line_chars(fd, buf, sizeof(buf))) > 0) {
1.52 + if (sz > kwlen && ::memcmp(buf+sz-kwlen, kw, kwlen) == 0) {
1.53 + // Extract addresses
1.54 + if (sscanf(buf, "%" SCNxPTR "-%" SCNxPTR, bottom, top) == 2) {
1.55 + uintptr_t sp = (uintptr_t) __builtin_frame_address(0);
1.56 + if (sp >= *bottom && sp <= *top) {
1.57 + ::close(fd);
1.58 + return true;
1.59 + }
1.60 }
1.61 - }
1.62 - }
1.63 - free(str);
1.64 + }
1.65 }
1.66 - fclose(f);
1.67 +
1.68 + ::close(fd);
1.69 return false;
1.70 }
1.71
1.72 +
1.73 // If the (growable) stack mapping already extends beyond the point
1.74 // where we're going to put our guard pages, truncate the mapping at
1.75 // that point by munmap()ping it. This ensures that when we later
