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#define _GNU_SOURCE
#define _LARGEFILE64_SOURCE
#include <asm/unistd_32.h>
#include <fcntl.h>
#include <limits.h>
#include <pwd.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/types.h>
#include <unistd.h>
#if !defined(__i386__)
#error "Compile this helper with -m32 so it exercises the compat syscall ABI."
#endif
static void
die(const char *msg)
{
perror(msg);
exit(1);
}
static void
must(bool ok, const char *msg)
{
if (!ok)
die(msg);
}
static void
must_eq(long rc, const char *msg)
{
if (rc == -1)
die(msg);
}
static void
write_pid_file(const char *path)
{
FILE *fp = fopen(path, "w");
must(fp != NULL, "fopen pid file");
fprintf(fp, "%ld\n", (long)getpid());
fclose(fp);
}
static void
wait_for_go(const char *path)
{
while (access(path, F_OK) != 0)
usleep(10000);
}
static void
write_full(int fd, const char *buf, size_t len)
{
while (len > 0) {
ssize_t written = write(fd, buf, len);
must_eq(written, "write");
buf += written;
len -= (size_t)written;
}
}
int
main(int argc, char **argv)
{
if (argc != 5) {
fprintf(stderr, "usage: %s PID_FILE GO_FILE BASE_DIR USER\n", argv[0]);
return 2;
}
const char *pid_file = argv[1];
const char *go_file = argv[2];
const char *base = argv[3];
const char *user = argv[4];
struct passwd *pw = getpwnam(user);
must(pw != NULL, "getpwnam");
must(pw->pw_uid <= USHRT_MAX, "uid fits 16-bit compat ABI");
must(pw->pw_gid <= USHRT_MAX, "gid fits 16-bit compat ABI");
write_pid_file(pid_file);
wait_for_go(go_file);
char path_file[1024];
char path_link[1024];
snprintf(path_file, sizeof(path_file), "%s/compat-open.txt", base);
snprintf(path_link, sizeof(path_link), "%s/compat-link.txt", base);
must_eq(mkdir(base, 0777), "mkdir compat base");
int dirfd = open(base, O_RDONLY | O_DIRECTORY);
must_eq(dirfd, "open compat base");
int fd = open(path_file, O_CREAT | O_RDWR | O_TRUNC, 0644);
must_eq(fd, "open compat-open.txt");
write_full(fd, "compat-data", 11);
must_eq(lseek(fd, 0, SEEK_SET), "lseek compat-open.txt");
must_eq(symlink(path_file, path_link), "symlink compat-link.txt");
char dir_buf[4096];
long long llseek_result = 0;
struct statfs64 sfs;
must_eq(syscall(__NR_readdir, dirfd, dir_buf, sizeof(dir_buf)),
"compat readdir");
must_eq(syscall(__NR__llseek, fd, 0UL, 0UL, &llseek_result, SEEK_END),
"compat _llseek");
must_eq(syscall(__NR_statfs64, base, sizeof(sfs), &sfs),
"compat statfs64");
must_eq(syscall(__NR_fstatfs64, fd, sizeof(sfs), &sfs),
"compat fstatfs64");
must_eq(syscall(__NR_chown, path_file, pw->pw_uid, pw->pw_gid),
"compat chown16");
must_eq(syscall(__NR_lchown, path_link, pw->pw_uid, pw->pw_gid),
"compat lchown16");
must_eq(syscall(__NR_fchown, fd, pw->pw_uid, pw->pw_gid),
"compat fchown16");
must_eq(close(fd), "close compat-open.txt");
must_eq(close(dirfd), "close compat base");
return 0;
}
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