When converting a siginfo_t from waitid(), the interpretation of si_status
depends on the value of si_code: For CLD_EXITED, it is an exit code and
should be copied verbatim. For other codes, it is a signal number
(possibly with additional high bits from ptrace) that should be mapped.
This code was previously changed in commit 1c3dfb506e
("linux-user/signal: Decode waitid si_code"), but the fix was
incomplete.
Tested with the following test program:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
int main() {
pid_t pid = fork();
if (pid == 0) {
exit(12);
} else {
siginfo_t siginfo = {};
waitid(P_PID, pid, &siginfo, WEXITED);
printf("Code: %d, status: %d\n", (int)siginfo.si_code, (int)siginfo.si_status);
}
pid = fork();
if (pid == 0) {
raise(SIGUSR2);
} else {
siginfo_t siginfo = {};
waitid(P_PID, pid, &siginfo, WEXITED);
printf("Code: %d, status: %d\n", (int)siginfo.si_code, (int)siginfo.si_status);
}
}
Output with an x86_64 host and mips64el target before 1c3dfb506e
(incorrect: exit code 12 is translated like a signal):
Code: 1, status: 17
Code: 2, status: 17
After 1c3dfb506e (incorrect: signal number is not translated):
Code: 1, status: 12
Code: 2, status: 12
With this patch:
Code: 1, status: 12
Code: 2, status: 17
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <81534fde7cdfc6acea4889d886fbefdd606630fb.1635019124.git.mschiffer@universe-factory.net>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
139e5de7c8