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strbuf: set the proper character when creating new nodes

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Commit 82501b3fc added an early break when a terminal node is found to
incorrect place -- before setting c. This caused trie to be built that
does not correspond to what it points to in buffer, causing incorrect
deduplications:

  # cat /etc/udev/rules.d/99-bug.rules
  ENV{FOO}=="0"
  ENV{xx0}=="BAR"
  ENV{BAZ}=="00"

  # udevadm test
  * RULE /etc/udev/rules.d/99-bug.rules:1, token: 0, count: 2, label: ''
  M ENV match 'FOO' '0'(plain)
  * RULE /etc/udev/rules.d/99-bug.rules:2, token: 2, count: 2, label: ''
  M ENV match 'xx0' 'BAR'(plain)
  * RULE /etc/udev/rules.d/99-bug.rules:3, token: 4, count: 2, label: ''
  M ENV match 'BAZ' 'x0'(plain)
  * END

The addition of "xx0" following "0" will cause a trie like this to be
created:

  c=\0
    c=0 "0"
      c=0 "xx0"  <-- note the c is incorrect here, causing "00" to be
    c=O "FOO"        deduplicated to it
    c=R "BAR"

This in effect caused the usb_modeswitch rule for Huawei modems to never
match and this never be switched to serial mode from mass storage.
This commit is contained in:
Lubomir Rintel 2016-05-03 22:15:49 +02:00
parent fa394301e2
commit c45606eb95
1 changed files with 2 additions and 1 deletions
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3
src/basic/strbuf.c
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@ -156,12 +156,13 @@ ssize_t strbuf_add_string(struct strbuf *str, const char *s, size_t len) {
return off;
}
c = s[len - 1 - depth];
/* bsearch is not allowed on a NULL sequence */
if (node->children_count == 0)
break;
/* lookup child node */
c = s[len - 1 - depth];
search.c = c;
child = bsearch(&search, node->children, node->children_count,
sizeof(struct strbuf_child_entry),