CAMLprim value caml_extunix_readlinkat(value v_dirfd, value v_name)
{
CAMLparam2(v_dirfd, v_name);
CAMLlocal1(v_link);
char* res;
char* p = caml_stat_alloc(caml_string_length(v_name) + 1);
strcpy(p, String_val(v_name));
caml_enter_blocking_section();
res = readlinkat_malloc(Int_val(v_dirfd), p);
caml_leave_blocking_section();
caml_stat_free(p);
if (res == NULL) uerror("readlinkat", v_name);
v_link = caml_copy_string(res);
free(res);
CAMLreturn(v_link);
}
static int fd_copy_symlink(int df, const char *from, const struct stat *st, int dt, const char *to) {
_cleanup_free_ char *target = NULL;
int r;
assert(from);
assert(st);
assert(to);
r = readlinkat_malloc(df, from, &target);
if (r < 0)
return r;
if (symlinkat(target, dt, to) < 0)
return -errno;
if (fchownat(dt, to, st->st_uid, st->st_gid, AT_SYMLINK_NOFOLLOW) < 0)
return -errno;
return 0;
}
/* Joins /proc/[pid]/fd/ and /proc/[pid]/fdinfo/ into the following lines:
* 0:/dev/pts/23
* pos: 0
* flags: 0100002
*
* 1:/dev/pts/23
* pos: 0
* flags: 0100002
*
* 2:/dev/pts/23
* pos: 0
* flags: 0100002
* EOF
*/
static int compose_open_fds(pid_t pid, char **open_fds) {
_cleanup_closedir_ DIR *proc_fd_dir = NULL;
_cleanup_close_ int proc_fdinfo_fd = -1;
_cleanup_free_ char *buffer = NULL;
_cleanup_fclose_ FILE *stream = NULL;
const char *fddelim = "", *path;
struct dirent *dent = NULL;
size_t size = 0;
int r = 0;
assert(pid >= 0);
assert(open_fds != NULL);
path = procfs_file_alloca(pid, "fd");
proc_fd_dir = opendir(path);
if (!proc_fd_dir)
return -errno;
proc_fdinfo_fd = openat(dirfd(proc_fd_dir), "../fdinfo", O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC|O_PATH);
if (proc_fdinfo_fd < 0)
return -errno;
stream = open_memstream(&buffer, &size);
if (!stream)
return -ENOMEM;
FOREACH_DIRENT(dent, proc_fd_dir, return -errno) {
_cleanup_fclose_ FILE *fdinfo = NULL;
_cleanup_free_ char *fdname = NULL;
char line[LINE_MAX];
int fd;
r = readlinkat_malloc(dirfd(proc_fd_dir), dent->d_name, &fdname);
if (r < 0)
return r;
fprintf(stream, "%s%s:%s\n", fddelim, dent->d_name, fdname);
fddelim = "\n";
/* Use the directory entry from /proc/[pid]/fd with /proc/[pid]/fdinfo */
fd = openat(proc_fdinfo_fd, dent->d_name, O_NOFOLLOW|O_CLOEXEC|O_RDONLY);
if (fd < 0)
continue;
fdinfo = fdopen(fd, "re");
if (fdinfo == NULL) {
close(fd);
continue;
}
FOREACH_LINE(line, fdinfo, break) {
fputs(line, stream);
if (!endswith(line, "\n"))
fputc('\n', stream);
}
}
errno = 0;
stream = safe_fclose(stream);
if (errno != 0)
return -errno;
*open_fds = buffer;
buffer = NULL;
return 0;
}
