Rename buffer.c -> logsrv_util.c and add iolog_seekto()

logsrvd/logsrv_util.c

@@ -0,0 +1,176 @@
+/*
+ * Copyright (c) 2019 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include "config.h"
+
+#include <sys/types.h>
+
+#include <errno.h>
+#ifdef HAVE_STDBOOL_H
+# include <stdbool.h>
+#else
+# include "compat/stdbool.h"
+#endif /* HAVE_STDBOOL_H */
+#if defined(HAVE_STDINT_H)
+# include <stdint.h>
+#elif defined(HAVE_INTTYPES_H)
+# include <inttypes.h>
+#endif
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+#include <unistd.h>
+
+#include "sudo_gettext.h"	/* must be included before sudo_compat.h */
+#include "sudo_compat.h"
+#include "sudo_debug.h"
+#include "sudo_util.h"
+#include "sudo_fatal.h"
+#include "sudo_iolog.h"
+#include "logsrv_util.h"
+
+/*
+ * Round 32-bit unsigned length to the next highest power of two.
+ * Always returns at least 64.
+ * Algorithm from bit twiddling hacks.
+ */
+unsigned int
+bufsize_roundup(unsigned int len)
+{
+    if (len < 64)
+	return 64;
+    len--;
+    len |= len >> 1;
+    len |= len >> 2;
+    len |= len >> 4;
+    len |= len >> 8;
+    len |= len >> 16;
+    len++;
+    return len;
+}
+
+/*
+ * Expand buf as needed or just reset it.
+ */
+bool
+expand_buf(struct connection_buffer *buf, unsigned int needed)
+{
+    void *newdata;
+    debug_decl(expand_buf, SUDO_DEBUG_UTIL)
+
+    if (buf->size < needed) {
+	/* Expand buffer. */
+	needed = bufsize_roundup(needed);
+	if ((newdata = malloc(needed)) == NULL) {
+	    sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_ERRNO,
+		"%s: unable to malloc %u", __func__, needed);
+	    debug_return_bool(false);
+	}
+	if (buf->off > 0)
+	    memcpy(newdata, buf->data + buf->off, buf->len - buf->off);
+	free(buf->data);
+	buf->data = newdata;
+	buf->size = needed;
+    } else {
+	/* Just reset existing buffer. */
+	if (buf->off > 0) {
+	    memmove(buf->data, buf->data + buf->off,
+		buf->len - buf->off);
+	}
+    }
+    buf->len -= buf->off;
+    buf->off = 0;
+
+    debug_return_bool(true);
+}
+
+/*
+ * Open any I/O log files that are present.
+ * The timing file must always exist.
+ */
+bool
+iolog_open_all(int dfd, const char *iolog_dir, struct iolog_file *iolog_files,
+    const char *mode)
+{
+    int iofd;
+    debug_decl(iolog_open_all, SUDO_DEBUG_UTIL)
+
+    for (iofd = 0; iofd < IOFD_MAX; iofd++) {
+	iolog_files[iofd].enabled = true;
+        if (!iolog_open(&iolog_files[iofd], dfd, iofd, mode)) {
+	    if (errno != ENOENT) {
+		sudo_warn(U_("unable to open %s/%s"), iolog_dir,
+		    iolog_fd_to_name(iofd));
+		debug_return_bool(false);
+	    }
+	}
+    }
+    if (!iolog_files[IOFD_TIMING].enabled) {
+	sudo_warn(U_("unable to open %s/%s"), iolog_dir,
+	    iolog_fd_to_name(IOFD_TIMING));
+	debug_return_bool(false);
+    }
+    debug_return_bool(true);
+}
+
+/*
+ * Seek to the specified point in time in the I/O logs.
+ */
+bool
+iolog_seekto(int iolog_dir_fd, const char *iolog_path,
+    struct iolog_file *iolog_files, struct timespec *elapsed_time,
+    const struct timespec *target)
+{
+    struct timing_closure timing;
+    off_t pos;
+    debug_decl(iolog_seekto, SUDO_DEBUG_UTIL)
+
+    /* Parse timing file until we reach the target point. */
+    for (;;) {
+	if (read_timing_record(&iolog_files[IOFD_TIMING], &timing) != 0)
+	    goto bad;
+	sudo_timespecadd(&timing.delay, elapsed_time, elapsed_time);
+	if (timing.event < IOFD_TIMING) {
+	    if (!iolog_files[timing.event].enabled) {
+		/* Missing log file. */
+		sudo_warn(U_("missing I/O log file %s/%s"), iolog_path,
+		    iolog_fd_to_name(timing.event));
+		goto bad;
+	    }
+	    pos = iolog_seek(&iolog_files[timing.event], timing.u.nbytes,
+		SEEK_CUR);
+	    if (pos == -1) {
+		sudo_warn(U_("%s/%s: unable to seek forward %zu"), iolog_path,
+		    iolog_fd_to_name(timing.event), timing.u.nbytes);
+		goto bad;
+	    }
+	}
+	if (sudo_timespeccmp(elapsed_time, target, >=)) {
+	    if (sudo_timespeccmp(elapsed_time, target, ==))
+		break;
+
+	    /* Mismatch between resume point and stored log. */
+	    sudo_warnx(U_("unable to find resume point [%lld, %ld] in %s/%s"),
+		(long long)target->tv_sec, target->tv_nsec, iolog_path,
+		"timing");
+	    goto bad;
+	}
+    }
+    debug_return_bool(true);
+bad:
+    debug_return_bool(false);
+}