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Merge pull request #7172 from hercules-ci/libmain-extraStackOverflowHandler

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libmain: Make stack overflow handler configurable
This commit is contained in:
Eelco Dolstra 2022-10-14 17:12:45 +02:00 committed by GitHub
commit 9f7877abac
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2 changed files with 29 additions and 3 deletions
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20
src/libmain/shared.hh
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@ -113,5 +113,25 @@ struct PrintFreed
/* Install a SIGSEGV handler to detect stack overflows. */
void detectStackOverflow();
/* Pluggable behavior to run in case of a stack overflow.
Default value: defaultStackOverflowHandler.
This is called by the handler installed by detectStackOverflow().
This gives Nix library consumers a limit opportunity to report the error
condition. The handler should exit the process.
See defaultStackOverflowHandler() for a reference implementation.
NOTE: Use with diligence, because this runs in the signal handler, with very
limited stack space and a potentially a corrupted heap, all while the failed
thread is blocked indefinitely. All functions called must be reentrant. */
extern std::function<void(siginfo_t * info, void * ctx)> stackOverflowHandler;
/* The default, robust implementation of stackOverflowHandler.
Prints an error message directly to stderr using a syscall instead of the
logger. Exits the process immediately after. */
void defaultStackOverflowHandler(siginfo_t * info, void * ctx);
}

12
src/libmain/stack.cc
View File

@ -1,4 +1,5 @@
#include "error.hh"
#include "shared.hh"
#include <cstring>
#include <cstddef>
@ -29,9 +30,7 @@ static void sigsegvHandler(int signo, siginfo_t * info, void * ctx)
ptrdiff_t diff = (char *) info->si_addr - sp;
if (diff < 0) diff = -diff;
if (diff < 4096) {
char msg[] = "error: stack overflow (possible infinite recursion)\n";
[[gnu::unused]] auto res = write(2, msg, strlen(msg));
_exit(1); // maybe abort instead?
nix::stackOverflowHandler(info, ctx);
}
}
@ -67,5 +66,12 @@ void detectStackOverflow()
#endif
}
std::function<void(siginfo_t * info, void * ctx)> stackOverflowHandler(defaultStackOverflowHandler);
void defaultStackOverflowHandler(siginfo_t * info, void * ctx) {
char msg[] = "error: stack overflow (possible infinite recursion)\n";
[[gnu::unused]] auto res = write(2, msg, strlen(msg));
_exit(1); // maybe abort instead?
}
}