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Introduce --strace flag for system call tracing

Browse source 
This is similar to the --ftrace (c function call trace) flag, except
it's less noisy since it only logs system calls to stderr. Having this
flag is valuable because (1) system call tracing tells us a lot about
the behavior of complex programs and (2) it's usually very hard to get
system call tracing on various operating systems, e.g. strace, ktrace,
dtruss, truss, nttrace, etc. Especially on Apple platforms where even
with the special boot trick, debuggers still aren't guaranteed to work.

    make -j8 o//examples
    o//examples/hello.com --strace

This is enabled by default in MODE=, MODE=opt, and MODE=dbg. In MODE=dbg
extra information will be printed.

    make -j8 MODE=dbg o/dbg/examples
    o/dbg/examples/hello.com --strace |& less

This change also changes:

- Rename IsText() → _istext()
- Rename IsUtf8() → _isutf8()
- Fix madvise() on Windows NT
- Fix empty string case of inet_ntop()
- vfork() wrapper now saves and restores errno
- Update xsigaction() to yoink syscall support
This commit is contained in:
Justine Tunney 2022-03-18 18:07:28 -07:00
parent c541225af0
commit 14e192e5ba
138 changed files with 1519 additions and 631 deletions
Download patch file Download diff file Expand all files Collapse all files

38
libc/calls/sigaction.c
View file

@ -21,6 +21,7 @@
#include "libc/calls/calls.h"
#include "libc/calls/internal.h"
#include "libc/calls/sigbits.h"
#include "libc/calls/strace.internal.h"
#include "libc/calls/struct/sigaction-freebsd.internal.h"
#include "libc/calls/struct/sigaction-linux.internal.h"
#include "libc/calls/struct/sigaction-netbsd.h"
@ -129,19 +130,8 @@ static void sigaction_native2cosmo(union metasigaction *sa) {
}
}
/**
* Installs handler for kernel interrupt, e.g.:
*
* void GotCtrlC(int sig, siginfo_t *si, ucontext_t *ctx);
* struct sigaction sa = {.sa_sigaction = GotCtrlC,
* .sa_flags = SA_RESETHAND|SA_RESTART|SA_SIGINFO};
* CHECK_NE(-1, sigaction(SIGINT, &sa, NULL));
*
* @see xsigaction() for a much better api
* @asyncsignalsafe
* @vforksafe
*/
int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
static int __sigaction(int sig, const struct sigaction *act,
struct sigaction *oldact) {
_Static_assert((sizeof(struct sigaction) > sizeof(struct sigaction_linux) &&
sizeof(struct sigaction) > sizeof(struct sigaction_xnu_in) &&
sizeof(struct sigaction) > sizeof(struct sigaction_xnu_out) &&
@ -233,3 +223,25 @@ int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
}
return rc;
}
/**
* Installs handler for kernel interrupt, e.g.:
*
* void GotCtrlC(int sig, siginfo_t *si, ucontext_t *ctx);
* struct sigaction sa = {.sa_sigaction = GotCtrlC,
* .sa_flags = SA_RESETHAND|SA_RESTART|SA_SIGINFO};
* CHECK_NE(-1, sigaction(SIGINT, &sa, NULL));
*
* @see xsigaction() for a much better api
* @asyncsignalsafe
* @vforksafe
*/
int(sigaction)(int sig, const struct sigaction *act, struct sigaction *oldact) {
int rc;
char buf[2][128];
rc = __sigaction(sig, act, oldact);
STRACE("sigaction(%s, %s, [%s]) → %d% m", strsignal(sig),
__strace_sigaction(buf[0], sizeof(buf[0]), 0, act),
__strace_sigaction(buf[1], sizeof(buf[1]), rc, oldact), rc);
return rc;
}