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Use err.h instead of self-implemented error output

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madmaurice 2021-01-15 20:22:22 +01:00
parent 13c7aa2ca4
commit 2f56f84214
1 changed files with 14 additions and 20 deletions
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34
main.c
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@ -2,6 +2,7 @@
#define _GNU_SOURCE
#include <sched.h>
#include <errno.h>
#include <err.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
@ -12,12 +13,6 @@
pid_t pid_child;
void fatal(const char* str, int errcode)
{
printf("%s (%d)\n", str, errcode);
exit(errcode);
}
void drop_root(void)
{
/// Drop root privileges
@ -25,15 +20,15 @@ void drop_root(void)
// be able to drop group once we dropped user
gid_t gid = getgid();
if (setresgid(-1,gid,gid) == -1)
fatal("Failed to drop root privileges with setresgid", errno);
err(errno, "Failed to drop root privileges with setresgid");
uid_t uid = getuid();
if (setresuid(-1,uid,uid) == -1)
fatal("Failed to drop root privileges with setresuid", errno);
err(errno, "Failed to drop root privileges with setresuid");
// sanity check
if (seteuid(0) != -1)
fatal("Sanity check failed. Able to regain root", 42);
errx(1, "Sanity check failed. Able to regain root");
}
struct sigaction forward_signal_descriptor;
@ -48,8 +43,6 @@ void forward_signal(int sig)
int main(int argc, char* const* argv)
{
int err;
forward_signal_descriptor.sa_flags = SA_RESTART;
forward_signal_descriptor.sa_handler = &forward_signal;
@ -64,7 +57,7 @@ int main(int argc, char* const* argv)
// next fork shall be in a new pid namespace
if (unshare(CLONE_NEWPID) != 0)
{
fatal("Failed to unshare pid namespace", errno);
err(errno, "Failed to unshare pid namespace");
}
// Drop root privileges, we only needed those for the unshare call.
@ -74,7 +67,7 @@ int main(int argc, char* const* argv)
if (pid == -1)
{
fatal("Failed to fork", errno);
err(errno, "Failed to fork");
}
if (pid != 0)
@ -94,7 +87,7 @@ int main(int argc, char* const* argv)
int status;
if (waitpid(pid, &status, 0) == -1)
{
fatal("Failed to wait for init process", errno);
err(errno, "Failed to wait for init process");
}
return WEXITSTATUS(status);
@ -109,7 +102,7 @@ int main(int argc, char* const* argv)
pid = fork();
if (pid == -1)
{
fatal("Failed to fork in init process", errno);
err(errno, "Failed to fork in init process");
}
if (pid != 0)
@ -133,18 +126,19 @@ int main(int argc, char* const* argv)
pid_child = first_child;
if (sigaction(SIGTERM, &forward_signal_descriptor, NULL) == -1)
{
fatal("Unable to setup signal forward in init", 1);
err(1, "Unable to setup signal forward in init");
}
int wait_errno;
// wait could be interrupt due to a signal. In that case just call wait again.
do {
exited_child = wait(&child_status);
err = errno;
} while (!(exited_child == first_child || (exited_child == -1 && err == ECHILD)));
wait_errno = errno;
} while (!(exited_child == first_child || (exited_child == -1 && wait_errno == ECHILD)));
if (exited_child == -1)
{
return err;
err(wait_errno, "Error while waiting for subprocess");
}
else
{
@ -159,7 +153,7 @@ int main(int argc, char* const* argv)
if (execvp(argv[0], argv) == -1)
{
fatal("Failed to exec", errno);
err(errno, "Failed to exec");
}
}
}