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authorLennart Poettering <lennart@poettering.net>2018-03-09 22:45:08 +0100
committerSven Eden <yamakuzure@gmx.net>2018-08-24 16:47:08 +0200
commitb9e2dff07fe8b82a50b081b6032e547632e338f9 (patch)
treea0bdb58cb9e53dab9d030210e5c4f38f00e2d00d /src/test
parent059f624b552e0cedf6683bd7dad62ed950e9f5b4 (diff)
fd-util: add new helper call fd_duplicate_data_fd()
This call creates an fd from another fd containing the same data. Specifically, repeated read() on the returned fd should return the same data as the original fd. This call is useful when we want to copy data out of disk images and suchlike, and want to be pass fds with the data around without having to keep the disk image continously mounted. The implementation tries to be somewhat smart and tries to prefer memfds/pipes over files in /tmp or /var/tmp based on the size of the data, but has appropropriate fallbacks in place.
Diffstat (limited to 'src/test')
-rw-r--r--src/test/test-fd-util.c88
1 files changed, 88 insertions, 0 deletions
diff --git a/src/test/test-fd-util.c b/src/test/test-fd-util.c
index f266e580b..edcb8ab75 100644
--- a/src/test/test-fd-util.c
+++ b/src/test/test-fd-util.c
@@ -230,6 +230,93 @@ static void test_rearrange_stdio(void) {
}
}
+static void assert_equal_fd(int fd1, int fd2) {
+
+ for (;;) {
+ uint8_t a[4096], b[4096];
+ ssize_t x, y;
+
+ x = read(fd1, a, sizeof(a));
+ assert(x >= 0);
+
+ y = read(fd2, b, sizeof(b));
+ assert(y >= 0);
+
+ assert(x == y);
+
+ if (x == 0)
+ break;
+
+ assert(memcmp(a, b, x) == 0);
+ }
+}
+
+static void test_fd_duplicate_data_fd(void) {
+ _cleanup_close_ int fd1 = -1, fd2 = -1;
+ _cleanup_(close_pairp) int sfd[2] = { -1, -1 };
+ _cleanup_(sigkill_waitp) pid_t pid = -1;
+ uint64_t i, j;
+ int r;
+
+ fd1 = open("/etc/fstab", O_RDONLY|O_CLOEXEC);
+ if (fd1 >= 0) {
+
+ fd2 = fd_duplicate_data_fd(fd1);
+ assert_se(fd2 >= 0);
+
+ assert_se(lseek(fd1, 0, SEEK_SET) == 0);
+ assert_equal_fd(fd1, fd2);
+ }
+
+ fd1 = safe_close(fd1);
+ fd2 = safe_close(fd2);
+
+ fd1 = acquire_data_fd("hallo", 6, 0);
+ assert_se(fd1 >= 0);
+
+ fd2 = fd_duplicate_data_fd(fd1);
+ assert_se(fd2 >= 0);
+
+ safe_close(fd1);
+ fd1 = acquire_data_fd("hallo", 6, 0);
+ assert_se(fd1 >= 0);
+
+ assert_equal_fd(fd1, fd2);
+
+ fd1 = safe_close(fd1);
+ fd2 = safe_close(fd2);
+
+ assert_se(socketpair(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0, sfd) >= 0);
+
+ r = safe_fork("(sd-pipe)", FORK_RESET_SIGNALS|FORK_DEATHSIG|FORK_LOG, &pid);
+ assert_se(r >= 0);
+
+ if (r == 0) {
+ /* child */
+
+ sfd[0] = safe_close(sfd[0]);
+
+ for (i = 0; i < 1536*1024 / sizeof(uint64_t); i++)
+ assert_se(write(sfd[1], &i, sizeof(i)) == sizeof(i));
+
+ sfd[1] = safe_close(sfd[1]);
+
+ _exit(EXIT_SUCCESS);
+ }
+
+ sfd[1] = safe_close(sfd[1]);
+
+ fd2 = fd_duplicate_data_fd(sfd[0]);
+ assert_se(fd2 >= 0);
+
+ for (i = 0; i < 1536*1024 / sizeof(uint64_t); i++) {
+ assert_se(read(fd2, &j, sizeof(j)) == sizeof(j));
+ assert_se(i == j);
+ }
+
+ assert_se(read(fd2, &j, sizeof(j)) == 0);
+}
+
int main(int argc, char *argv[]) {
test_close_many();
test_close_nointr();
@@ -240,6 +327,7 @@ int main(int argc, char *argv[]) {
test_acquire_data_fd();
test_fd_move_above_stdio();
test_rearrange_stdio();
+ test_fd_duplicate_data_fd();
return 0;
}