Files
clang-p2996/lldb/test/python_api/hello_world/main.c
Todd Fiala f183754779 Fix HelloWorld attach test for Linux kernels with ptrace ancestor lockdown.
Similar to a recent test I fixed for gdb-remote attach scenarios, this
fix is for Linux kernels, such as Ubuntu's stock setup on 11.04-ish and
later, where ptrace starts requiring a ptracer to be an ancestor of the
inferior to be ptraced.  This change checks for Linux and the ptrace-related
flags.  If they're found, it tries to switch on the "allow any ptracer" mode
for the inferior as the first statements in the program.  It's a best-effort
solution - if the prctl call fails, the failure is ignored, and probably will
lead to the test failing.

The ptrace security behavior can be modified system-wide, but is outside the
scope of the test to address.  Hence I went with this particular solution.

llvm-svn: 220650
2014-10-26 21:37:46 +00:00

36 lines
1.0 KiB
C

#include <stdio.h>
#if defined(__linux__)
#include <sys/prctl.h>
#endif
int main(int argc, char const *argv[]) {
#if defined(__linux__)
// Immediately enable any ptracer so that we can allow the stub attach
// operation to succeed. Some Linux kernels are locked down so that
// only an ancestor process can be a ptracer of a process. This disables that
// restriction. Without it, attach-related stub tests will fail.
#if defined(PR_SET_PTRACER) && defined(PR_SET_PTRACER_ANY)
int prctl_result;
// For now we execute on best effort basis. If this fails for
// some reason, so be it.
prctl_result = prctl(PR_SET_PTRACER, PR_SET_PTRACER_ANY, 0, 0, 0);
(void) prctl_result;
#endif
#endif
printf("Hello world.\n"); // Set break point at this line.
if (argc == 1)
return 0;
// Waiting to be attached by the debugger, otherwise.
char line[100];
while (fgets(line, sizeof(line), stdin)) { // Waiting to be attached...
printf("input line=>%s\n", line);
}
printf("Exiting now\n");
}