linux-user: fix /proc/self/stat handling
In the original bug report long files names in Guix caused
/proc/self/stat be truncated without the trailing ") " as specified in
proc manpage which says:
(2) comm %s
The filename of the executable, in parentheses. This
is visible whether or not the executable is swapped
out.
In the kernel this is currently done by do_task_stat calling
proc_task_name() which uses a structure limited by TASK_COMM_LEN (16).
Additionally it should only be reporting the executable name rather
than the full path. Fix both these failings while cleaning up the code
to use GString to build up the reported values. As the whole function
is cleaned up also adjust the white space to the current coding style.
Message-ID: <fb4c55fa-d539-67ee-c6c9-de8fb63c8488@inria.fr>
Reported-by: Brice Goglin <Brice.Goglin@inria.fr>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20200414200631.12799-10-alex.bennee@linaro.org>
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 6495ddc..674f70e 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -7295,34 +7295,29 @@
{
CPUState *cpu = env_cpu((CPUArchState *)cpu_env);
TaskState *ts = cpu->opaque;
- abi_ulong start_stack = ts->info->start_stack;
+ g_autoptr(GString) buf = g_string_new(NULL);
int i;
for (i = 0; i < 44; i++) {
- char buf[128];
- int len;
- uint64_t val = 0;
+ if (i == 0) {
+ /* pid */
+ g_string_printf(buf, FMT_pid " ", getpid());
+ } else if (i == 1) {
+ /* app name */
+ gchar *bin = g_strrstr(ts->bprm->argv[0], "/");
+ bin = bin ? bin + 1 : ts->bprm->argv[0];
+ g_string_printf(buf, "(%.15s) ", bin);
+ } else if (i == 27) {
+ /* stack bottom */
+ g_string_printf(buf, TARGET_ABI_FMT_ld " ", ts->info->start_stack);
+ } else {
+ /* for the rest, there is MasterCard */
+ g_string_printf(buf, "0%c", i == 43 ? '\n' : ' ');
+ }
- if (i == 0) {
- /* pid */
- val = getpid();
- snprintf(buf, sizeof(buf), "%"PRId64 " ", val);
- } else if (i == 1) {
- /* app name */
- snprintf(buf, sizeof(buf), "(%s) ", ts->bprm->argv[0]);
- } else if (i == 27) {
- /* stack bottom */
- val = start_stack;
- snprintf(buf, sizeof(buf), "%"PRId64 " ", val);
- } else {
- /* for the rest, there is MasterCard */
- snprintf(buf, sizeof(buf), "0%c", i == 43 ? '\n' : ' ');
- }
-
- len = strlen(buf);
- if (write(fd, buf, len) != len) {
- return -1;
- }
+ if (write(fd, buf->str, buf->len) != buf->len) {
+ return -1;
+ }
}
return 0;
