Adding upstream version 241.upstream/241upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 264 insertions, 0 deletions

diff --git a/src/basic/io-util.c b/src/basic/io-util.c
new file mode 100644
index 0000000..575398f
--- /dev/null
+++ b/src/basic/io-util.c
@@ -0,0 +1,264 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <errno.h>
+#include <limits.h>
+#include <poll.h>
+#include <stdio.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "io-util.h"
+#include "string-util.h"
+#include "time-util.h"
+
+int flush_fd(int fd) {
+        struct pollfd pollfd = {
+                .fd = fd,
+                .events = POLLIN,
+        };
+        int count = 0;
+
+        /* Read from the specified file descriptor, until POLLIN is not set anymore, throwing away everything
+         * read. Note that some file descriptors (notable IP sockets) will trigger POLLIN even when no data can be read
+         * (due to IP packet checksum mismatches), hence this function is only safe to be non-blocking if the fd used
+         * was set to non-blocking too. */
+
+        for (;;) {
+                char buf[LINE_MAX];
+                ssize_t l;
+                int r;
+
+                r = poll(&pollfd, 1, 0);
+                if (r < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        return -errno;
+
+                } else if (r == 0)
+                        return count;
+
+                l = read(fd, buf, sizeof(buf));
+                if (l < 0) {
+
+                        if (errno == EINTR)
+                                continue;
+
+                        if (errno == EAGAIN)
+                                return count;
+
+                        return -errno;
+                } else if (l == 0)
+                        return count;
+
+                count += (int) l;
+        }
+}
+
+ssize_t loop_read(int fd, void *buf, size_t nbytes, bool do_poll) {
+        uint8_t *p = buf;
+        ssize_t n = 0;
+
+        assert(fd >= 0);
+        assert(buf);
+
+        /* If called with nbytes == 0, let's call read() at least
+         * once, to validate the operation */
+
+        if (nbytes > (size_t) SSIZE_MAX)
+                return -EINVAL;
+
+        do {
+                ssize_t k;
+
+                k = read(fd, p, nbytes);
+                if (k < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        if (errno == EAGAIN && do_poll) {
+
+                                /* We knowingly ignore any return value here,
+                                 * and expect that any error/EOF is reported
+                                 * via read() */
+
+                                (void) fd_wait_for_event(fd, POLLIN, USEC_INFINITY);
+                                continue;
+                        }
+
+                        return n > 0 ? n : -errno;
+                }
+
+                if (k == 0)
+                        return n;
+
+                assert((size_t) k <= nbytes);
+
+                p += k;
+                nbytes -= k;
+                n += k;
+        } while (nbytes > 0);
+
+        return n;
+}
+
+int loop_read_exact(int fd, void *buf, size_t nbytes, bool do_poll) {
+        ssize_t n;
+
+        n = loop_read(fd, buf, nbytes, do_poll);
+        if (n < 0)
+                return (int) n;
+        if ((size_t) n != nbytes)
+                return -EIO;
+
+        return 0;
+}
+
+int loop_write(int fd, const void *buf, size_t nbytes, bool do_poll) {
+        const uint8_t *p = buf;
+
+        assert(fd >= 0);
+        assert(buf);
+
+        if (_unlikely_(nbytes > (size_t) SSIZE_MAX))
+                return -EINVAL;
+
+        do {
+                ssize_t k;
+
+                k = write(fd, p, nbytes);
+                if (k < 0) {
+                        if (errno == EINTR)
+                                continue;
+
+                        if (errno == EAGAIN && do_poll) {
+                                /* We knowingly ignore any return value here,
+                                 * and expect that any error/EOF is reported
+                                 * via write() */
+
+                                (void) fd_wait_for_event(fd, POLLOUT, USEC_INFINITY);
+                                continue;
+                        }
+
+                        return -errno;
+                }
+
+                if (_unlikely_(nbytes > 0 && k == 0)) /* Can't really happen */
+                        return -EIO;
+
+                assert((size_t) k <= nbytes);
+
+                p += k;
+                nbytes -= k;
+        } while (nbytes > 0);
+
+        return 0;
+}
+
+int pipe_eof(int fd) {
+        struct pollfd pollfd = {
+                .fd = fd,
+                .events = POLLIN|POLLHUP,
+        };
+
+        int r;
+
+        r = poll(&pollfd, 1, 0);
+        if (r < 0)
+                return -errno;
+
+        if (r == 0)
+                return 0;
+
+        return pollfd.revents & POLLHUP;
+}
+
+int fd_wait_for_event(int fd, int event, usec_t t) {
+
+        struct pollfd pollfd = {
+                .fd = fd,
+                .events = event,
+        };
+
+        struct timespec ts;
+        int r;
+
+        r = ppoll(&pollfd, 1, t == USEC_INFINITY ? NULL : timespec_store(&ts, t), NULL);
+        if (r < 0)
+                return -errno;
+        if (r == 0)
+                return 0;
+
+        return pollfd.revents;
+}
+
+static size_t nul_length(const uint8_t *p, size_t sz) {
+        size_t n = 0;
+
+        while (sz > 0) {
+                if (*p != 0)
+                        break;
+
+                n++;
+                p++;
+                sz--;
+        }
+
+        return n;
+}
+
+ssize_t sparse_write(int fd, const void *p, size_t sz, size_t run_length) {
+        const uint8_t *q, *w, *e;
+        ssize_t l;
+
+        q = w = p;
+        e = q + sz;
+        while (q < e) {
+                size_t n;
+
+                n = nul_length(q, e - q);
+
+                /* If there are more than the specified run length of
+                 * NUL bytes, or if this is the beginning or the end
+                 * of the buffer, then seek instead of write */
+                if ((n > run_length) ||
+                    (n > 0 && q == p) ||
+                    (n > 0 && q + n >= e)) {
+                        if (q > w) {
+                                l = write(fd, w, q - w);
+                                if (l < 0)
+                                        return -errno;
+                                if (l != q -w)
+                                        return -EIO;
+                        }
+
+                        if (lseek(fd, n, SEEK_CUR) == (off_t) -1)
+                                return -errno;
+
+                        q += n;
+                        w = q;
+                } else if (n > 0)
+                        q += n;
+                else
+                        q++;
+        }
+
+        if (q > w) {
+                l = write(fd, w, q - w);
+                if (l < 0)
+                        return -errno;
+                if (l != q - w)
+                        return -EIO;
+        }
+
+        return q - (const uint8_t*) p;
+}
+
+char* set_iovec_string_field(struct iovec *iovec, size_t *n_iovec, const char *field, const char *value) {
+        char *x;
+
+        x = strappend(field, value);
+        if (x)
+                iovec[(*n_iovec)++] = IOVEC_MAKE_STRING(x);
+        return x;
+}