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From 1466d84c159c1a9d1839c1b346906b722e6311a3 Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Fri, 24 Jul 2015 01:40:44 +0200
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Subject: [PATCH] journal-verify: don't hit SIGFPE when determining progress
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If we determine the progress based on a number of objects available,
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don't blindly devide by the number of objects, given that it might be 0.
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Cherry-picked from: 45c047b227d96e98e7076c15ae774ff6390dc403
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Related: #1350232
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---
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 src/journal/journal-verify.c | 16 +++++++++++++---
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 1 file changed, 13 insertions(+), 3 deletions(-)
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diff --git a/src/journal/journal-verify.c b/src/journal/journal-verify.c
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index b03335ef3..983217c1b 100644
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--- a/src/journal/journal-verify.c
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+++ b/src/journal/journal-verify.c
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@@ -69,6 +69,16 @@ static void draw_progress(uint64_t p, usec_t *last_usec) {
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         fflush(stdout);
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 }
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+static uint64_t scale_progress(uint64_t scale, uint64_t p, uint64_t m) {
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+
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+        /* Calculates scale * p / m, but handles m == 0 safely, and saturates */
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+
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+        if (p >= m || m == 0)
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+                return scale;
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+
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+        return scale * p / m;
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+}
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+
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 static void flush_progress(void) {
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         unsigned n, i;
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@@ -584,7 +594,7 @@ static int verify_hash_table(
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                 uint64_t last = 0, p;
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                 if (show_progress)
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-                        draw_progress(0xC000 + (0x3FFF * i / n), last_usec);
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+                        draw_progress(0xC000 + scale_progress(0x3FFF, i, n), last_usec);
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                 p = le64toh(f->data_hash_table[i].head_hash_offset);
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                 while (p != 0) {
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@@ -726,7 +736,7 @@ static int verify_entry_array(
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                 Object *o;
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                 if (show_progress)
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-                        draw_progress(0x8000 + (0x3FFF * i / n), last_usec);
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+                        draw_progress(0x8000 + scale_progress(0x3FFF, i, n), last_usec);
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                 if (a == 0) {
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                         error(a, "array chain too short at %"PRIu64" of %"PRIu64, i, n);
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@@ -863,7 +873,7 @@ int journal_file_verify(
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         p = le64toh(f->header->header_size);
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         while (p != 0) {
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                 if (show_progress)
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-                        draw_progress(0x7FFF * p / le64toh(f->header->tail_object_offset), &last_usec);
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+                        draw_progress(scale_progress(0x7FFF, p, le64toh(f->header->tail_object_offset)), &last_usec);
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                 r = journal_file_move_to_object(f, OBJECT_UNUSED, p, &o);
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                 if (r < 0) {