• ~/.mutt/aliases, a flat text file consisting of mutt alias commands
• lbdb configuration to query ~/.mutt/aliases, Debian s LDAP database, and Canonical s LDAP database, so that I can search by name with Ctrl-t in mutt when composing a new message
• Google Contacts, which I used from Android and was completely separate from all of the above

• free software throughout
• storage under my control
• single common database
• minimal manual transcription when consolidating existing databases
• integration with Android such that I can continue using the same contacts, messaging, etc. apps
• integration with mutt such that I can continue using the same query interface
• not having to write my own software, because honestly

[uwsgi]
socket = 127.0.0.1:8801
uid = xandikos
gid = xandikos
umask = 022
master = true
cheaper = 2
processes = 4
plugin = python3
module = xandikos.wsgi:app
env = XANDIKOSPATH=/srv/xandikos/collections

<VirtualHost *:443>
        ServerName xandikos.example.org
        ServerAdmin me@example.org
        ErrorLog /var/log/apache2/xandikos-error.log
        TransferLog /var/log/apache2/xandikos-access.log
        <Location />
                ProxyPass "uwsgi://127.0.0.1:8801/"
                AuthType Basic
                AuthName "Xandikos"
                AuthBasicProvider file
                AuthUserFile "/etc/apache2/xandikos.passwd"
                Require valid-user
        </Location>
</VirtualHost>

[general]
status_path = "~/.vdirsyncer/status/"
[pair contacts]
a = "contacts_local"
b = "contacts_remote"
collections = ["from a", "from b"]
[storage contacts_local]
type = "filesystem"
path = "~/.contacts/"
fileext = ".vcf"
[storage contacts_remote]
type = "carddav"
url = "<Xandikos base URL>"
username = "<my username>"
password = "<my password>"

[addressbooks]
[[contacts]]
path = ~/.contacts/<UUID of my contacts collection>/
[general]
debug = no
default_action = list
editor = vim
merge_editor = vimdiff
[contact table]
# display names by first or last name: first_name / last_name
display = first_name
# group by address book: yes / no
group_by_addressbook = no
# reverse table ordering: yes / no
reverse = no
# append nicknames to name column: yes / no
show_nicknames = no
# show uid table column: yes / no
show_uids = yes
# sort by first or last name: first_name / last_name
sort = first_name
[vcard]
# extend contacts with your own private objects
# these objects are stored with a leading "X-" before the object name in the vcard files
# every object label may only contain letters, digits and the - character
# example:
#   private_objects = Jabber, Skype, Twitter
private_objects = Jabber, Skype, Twitter
# preferred vcard version: 3.0 / 4.0
preferred_version = 3.0
# Look into source vcf files to speed up search queries: yes / no
search_in_source_files = no
# skip unparsable vcard files: yes / no
skip_unparsable = no

#! /bin/sh
m_khard_query ()  
    khard email --parsable --remove-first-line --search-in-source-files "$1"
 

MODULES_PATH="$MODULES_PATH $HOME/.lbdb/modules"
METHODS='m_muttalias m_khard m_ldap'
LDAP_NICKS='debian canonical'

• the command modifier key ( ). It's a small thing but its use on the Mac platform is very consistent, and since it's not used at all within terminals, there's never a clash between window management and terminal applications. Compared to the morass of modifier keys on Linux, I will miss it. It's possible if I settle on a desktop environment and spend some time configuring it I can get to a similarly comfortable place. Similarly, I'd like to stick to one clipboard, and if possible, ignore the select-to-copy, middle-click-to-paste one entirely. This may be an issue for older software.
• The Mac hardware trackpad and gestures are honestly fantastic. I still have some residual muscle memory of using the Thinkpad trackpoint, and so I'm weaning myself off the trackpad by using an external thinkpad keyboard with the work Mac, and increasingly using a x61s where possible.
• SizeUp. I wrote about this in useful mac programs. It's a window management helper that lets you use keyboard shortcuts to move move and resize windows. I may need something similar, depending on what desktop environment I settle on. (I'm currently evaluating Awesome WM).
• 1Password. These days I think a password manager is an essential piece of software, and 1Password is a very, very good example of one. There are several other options now, but sadly none that seem remotely as nice as 1Password. Ryan C Gordon wrote 1pass, a Linux-compatible tool to read a 1Password keychain, but it's quite raw and needs some love. By coincidence that's currently his focus, and one can support him in this work via his Patreon.
• Font rendering. Both monospace and regular fonts look fantastic out of the box on a Mac, and it can be quite hard to switch back and forth between a Mac and Linux due to the difference in quality. I think this is a mixture of ensuring the font rendering software on Linux is configured properly, but also that I install a reasonable selection of fonts.

My implementation on display next to a real PDP-8/e at VCFe 18.0

The Original DEC started the PDP-8 line of computers programmed data processors designed as low cost machines in 1965. It is a quite minimalist 12 bit architecture based on the earlier PDP-5, and by minimalist I mean seriously minimal. If you are familiar with early 8 bit microprocessors like the 6502 or 8080 you will find them luxuriously equipped in comparison. The PDP-8 base architecture has a program counter (PC) and an accumulator (AC)¹. That s it. There are no pointer or index registers². There is no stack. It has addition and AND instructions but subtractions and OR operations have to be manually coded. The optional Extended Arithmetic Element adds the MQ register but that s really it for visible registers. The Wikipedia page on the PDP-8 has a good detailed description. Regarding technology, the PDP-8 series has been in production long enough to get the whole range of implementations from discrete transistor logic to microprocessors. The 8/e which I target was right in the middle, implemented in TTL logic where each IC contains multiple logic elements. This allowed the CPU itself (including timing generator) to fit on three large circuit boards plugged into a backplane. Complete systems would have at least another board for the front panel and multiple boards for the core memory, then additional boards for whatever options and peripherals were desired.

Design Choices and Comparisons I m not the only one who had the idea to build something like that, of course. Among the other modern PDP-8 implementations with a front panel, probably the most prominent project is the Spare Time Gizmos SBC6120 which is a PDP-8 single board computer built around the Harris/Intersil HD-6120 microprocessor, which implementes the PDP-8 architecture, combined with a nice front panel. Another is the PiDP-8/I, which is another nice front panel (modeled after the 8/i which has even more lights) driven by the simh simulator running under Linux on a Raspberry Pi. My goal is to get front panel lights that appear exactly like the real ones in operation. This necessitates driving the lights at full speed as they change with every instruction or even within instructions for some display selections. For example, if you run a tight loop that does nothing but increment AC while displaying that register, it would appear that all lights are lit at equal but less than full brightness. The reason is that the loop runs at such a high speed that even the most significant bit, which is blinking the slowest, is too fast to see flicker. Hence they are all effectively 50% on, just at different frequencies, and appear to be constantly light at the same brightness. This is where the other projects lack what I am looking for. The PiDP-8/I is a multiplexed display which updates at something like 30 Hz or 60 Hz, taking whatever value is current in the simulation software at the time. All the states the lights took inbetween are lost and consequently there is flickering where there shouldn t be. On the SBC6120 at least the address lines appear to update at full speed as these are the actual RAM address lines. However the used 6120 microprocessor does not have required data for the indicator display externally available. Instead, the SBC6120 runs an interrupt at 30 Hz to trap into its firmware/monitor program which then reads the current state and writes it to the front panel display, which is essentially just another peripheral. A different considerable problem with the SBC6120 is its use of the 6100 microprocessor family ICs, which are themselves long out of production and not trivial (or cheaply) to come by. Given that the way to go is to drive all lights in step with every cycle³, this can be done by a software running on a dedicated microcontroller which is how I started or by implementing a real CPU with all the needed outputs in an FPGA which is the project I am writing about. In the next post I give an overview of the hardware I built so far and some of the features that are yet to be implemented.

---

1. With an associated link bit which is a little different from a carry bit in that it is treated as a thirteenth bit, i.e. it will be flipped rather than set when a carry occurs. ^[return]
2. Although there are 8 specially treated memory addresses that will pre-increment when used in indirect addressing. ^[return]
3. Basic cycles on the PDP-8/e are 1.4 s for memory modifying cycles and fast cycles of 1.2 s for everything else. Instructions can be one to three cycles long. ^[return]

• The redis-server binary must be executable, to the redis-user, otherwise it won't run.
• /usr/bin/git must be executable to the git user.

• When a binary is executed the sha1 hash is calculated of the files contents.
• If that matches the value stored in an extended attribute the execution is permitted.
  • If the extended-attribute is missing, or the checksum doesn't match, then the execution is denied.

• If /usr/bin/perl is whitelisted then /usr/bin/perl /tmp/exploit.pl will succeed.
• If /usr/bin/python is whitelisted then the same applies.

(Yes I know about IMA and EVM - this was a simple project for learning purposes. Public-key signatures will be something I'll look at next/soon/later. :)

 $ apt-cache search cross-build-essential
crossbuild-essential-arm64 - Informational list of cross-build-essential packages for
crossbuild-essential-armel - ...
crossbuild-essential-armhf - ...
crossbuild-essential-mipsel - ...
crossbuild-essential-powerpc - ...
crossbuild-essential-ppc64el - ...
                                                                                        

sudo debootstrap stretch /var/lib/container/stretch http://deb.debian.org/debian
echo "strech_cross"   sudo tee /var/lib/container/stretch/etc/debian_chroot
sudo systemd-nspawn -D /var/lib/container/stretch

# Tell dpkg we can install arm64
dpkg --add-architecture arm64
# Add src line to make "apt-get source" work
echo "deb-src http://deb.debian.org/debian stretch main" >> /etc/apt/sources.list
apt-get update
# Install cross-compiler and other essential build tools
apt install --no-install-recommends build-essential crossbuild-essential-arm64

# Get qemu sources from debian
apt-get source qemu
cd qemu-*
# New in stretch: build-dep works in unpacked source tree 
apt-get build-dep -a arm64 .
# Cross-build Qemu for arm64
dpkg-buildpackage -aarm64 -j6 -b

• an interruption of the work-part should be immediately restarted
• an interruption of the sleep-part should go immediately into the work-part

workfun <- function()  
  i <- 1
  do_repeat <- FALSE
  while (TRUE)  
    message("begin of the loop")
    withRestarts(
       
        # do all the work here
        cat("Entering work part i =", i, "\n");
        Sys.sleep(10)
        i <- i + 1
        cat("finished work part\n")
       , 
      gotSIG = function()   
        message("interrupted while working, restarting work part")
        do_repeat <<- TRUE
        NULL
       
    )
    if (do_repeat)  
      cat("restarting work loop\n")
      do_repeat <- FALSE
      next
      else  
      cat("between work and sleep part\n")
     
    withRestarts(
       
        # do the sleep part here
        cat("Entering sleep part i =", i, "\n")
        Sys.sleep(10)
        i <- i + 1
        cat("finished sleep part\n")
       , 
      gotSIG = function()  
        message("got work to do, waking up!")
        NULL
       
    )
    message("end of the loop")
   
 
cat("Current process:", Sys.getpid(), "\n");
withCallingHandlers( 
    workfun()
   ,
  interrupt = function(e)  
    invokeRestart("gotSIG")
   )

1. Cheap but sturdy. Total cost will be under $2500. It would probably cost at least twice as much to get a professional install, and the pros might not even want to do such a small install.
2. Learn the roof mount system. I want to be able to add more panels, remove panels when working on the roof, and understand everything.
3. Make every day a sunny day. With my current solar panels, I get around 10x as much power on a sunny day as a cloudy day, and I have plenty of power on sunny days. So 10x the PV capacity should be a good amount of power all the time.

• local delivery (RTN_LOCAL),
• forwarding to a supplied next hop (RTN_UNICAST),
• silent discard (RTN_BLACKHOLE).

Route lookup in a trie Looking up a route in a routing table is to find the most specific prefix matching the requested destination. Let s assume the following routing table:

$ ip route show scope global table 100
default via 203.0.113.5 dev out2
192.0.2.0/25
        nexthop via 203.0.113.7  dev out3 weight 1
        nexthop via 203.0.113.9  dev out4 weight 1
192.0.2.47 via 203.0.113.3 dev out1
192.0.2.48 via 203.0.113.3 dev out1
192.0.2.49 via 203.0.113.3 dev out1
192.0.2.50 via 203.0.113.3 dev out1

Here are some examples of lookups and the associated results:

Destination IP	Next hop
192.0.2.49	203.0.113.3 via out1
192.0.2.50	203.0.113.3 via out1
192.0.2.51	203.0.113.7 via out3 or 203.0.113.9 via out4 (ECMP)
192.0.2.200	203.0.113.5 via out2

A common structure for route lookup is the trie, a tree structure where each node has its parent as prefix.

Lookup with a simple trie The following trie encodes the previous routing table: For each node, the prefix is known by its path from the root node and the prefix length is the current depth. A lookup in such a trie is quite simple: at each step, fetch the n^th bit of the IP address, where n is the current depth. If it is 0, continue with the first child. Otherwise, continue with the second. If a child is missing, backtrack until a routing entry is found. For example, when looking for 192.0.2.50, we will find the result in the corresponding leaf (at depth 32). However for 192.0.2.51, we will reach 192.0.2.50/31 but there is no second child. Therefore, we backtrack until the 192.0.2.0/25 routing entry. Adding and removing routes is quite easy. From a performance point of view, the lookup is done in constant time relative to the number of routes (due to maximum depth being capped to 32). Quagga is an example of routing software still using this simple approach.

Lookup with a path-compressed trie In the previous example, most nodes only have one child. This leads to a lot of unneeded bitwise comparisons and memory is also wasted on many nodes. To overcome this problem, we can use path compression: each node with only one child is removed (except if it also contains a routing entry). Each remaining node gets a new property telling how many input bits should be skipped. Such a trie is also known as a Patricia trie or a radix tree. Here is the path-compressed version of the previous trie: Since some bits have been ignored, on a match, a final check is executed to ensure all bits from the found entry are matching the input IP address. If not, we must act as if the entry wasn t found (and backtrack to find a matching prefix). The following figure shows two IP addresses matching the same leaf: The reduction on the average depth of the tree compensates the necessity to handle those false positives. The insertion and deletion of a routing entry is still easy enough. Many routing systems are using Patricia trees:

• OpenBSD
• NetBSD
• FreeBSD
• GoBGP (through go-radix)
• Linux for IPv6

Lookup with a level-compressed trie In addition to path compression, level compression² detects parts of the trie that are densily populated and replace them with a single node and an associated vector of 2^k children. This node will handle k input bits instead of just one. For example, here is a level-compressed version our previous trie: Such a trie is called LC-trie or LPC-trie and offers higher lookup performances compared to a radix tree. An heuristic is used to decide how many bits a node should handle. On Linux, if the ratio of non-empty children to all children would be above 50% when the node handles an additional bit, the node gets this additional bit. On the other hand, if the current ratio is below 25%, the node loses the responsibility of one bit. Those values are not tunable. Insertion and deletion becomes more complex but lookup times are also improved.

Implementation in Linux The implementation for IPv4 in Linux exists since 2.6.13 (commit 19baf839ff4a) and is enabled by default since 2.6.39 (commit 3630b7c050d9). Here is the representation of our example routing table in memory³: There are several structures involved:

• struct fib_table represents a routing table,
• struct trie represents a complete trie,
• struct key_vector represents either an internal node (when bits is not zero) or a leaf,
• struct fib_info contains the characteristics shared by several routes (like a next-hop gateway and an output interface),
• struct fib_alias is the glue between the leaves and the fib_info structures.

The trie can be retrieved through /proc/net/fib_trie:

$ cat /proc/net/fib_trie
Id 100:
  +-- 0.0.0.0/0 2 0 2
      -- 0.0.0.0
        /0 universe UNICAST
     +-- 192.0.2.0/26 2 0 1
         -- 192.0.2.0
           /25 universe UNICAST
         -- 192.0.2.47
           /32 universe UNICAST
        +-- 192.0.2.48/30 2 0 1
            -- 192.0.2.48
              /32 universe UNICAST
            -- 192.0.2.49
              /32 universe UNICAST
            -- 192.0.2.50
              /32 universe UNICAST
[...]

For internal nodes, the numbers after the prefix are:

1. the number of bits handled by the node,
2. the number of full children (they only handle one bit),
3. the number of empty children.

Moreover, if the kernel was compiled with CONFIG_IP_FIB_TRIE_STATS, some interesting statistics are available in /proc/net/fib_triestat⁴:

$ cat /proc/net/fib_triestat
Basic info: size of leaf: 48 bytes, size of tnode: 40 bytes.
Id 100:
        Aver depth:     2.33
        Max depth:      3
        Leaves:         6
        Prefixes:       6
        Internal nodes: 3
          2: 3
        Pointers: 12
Null ptrs: 4
Total size: 1  kB
[...]

When a routing table is very dense, a node can handle many bits. For example, a densily populated routing table with 1 million entries packed in a /12 can have one internal node handling 20 bits. In this case, route lookup is essentially reduced to a lookup in a vector. The following graph shows the number of internal nodes used relative to the number of routes for different scenarios (routes extracted from an Internet full view, /32 routes spreaded over 4 different subnets with various densities). When routes are densily packed, the number of internal nodes are quite limited.

Performance So how performant is a route lookup? The maximum depth stays low (about 6 for a full view), so a lookup should be quite fast. With the help of a small kernel module, we can accurately benchmark⁵ the fib_lookup() function: The lookup time is loosely tied to the maximum depth. When the routing table is densily populated, the maximum depth is low and the lookup times are fast. When forwarding at 10 Gbps, the time budget for a packet would be about 50 ns. Since this is also the time needed for the route lookup alone in some cases, we wouldn t be able to forward at line rate with only one core. Nonetheless, the results are pretty good and they are expected to scale linearly with the number of cores. The measurements are done with a Linux kernel 4.11 from Debian unstable. I have gathered performance metrics accross kernel versions in Performance progression of IPv4 route lookup on Linux . Another interesting figure is the time it takes to insert all those routes into the kernel. Linux is also quite efficient in this area since you can insert 2 million routes in less than 10 seconds:

Memory usage The memory usage is available directly in /proc/net/fib_triestat. The statistic provided doesn t account for the fib_info structures, but you should only have a handful of them (one for each possible next-hop). As you can see on the graph below, the memory use is linear with the number of routes inserted, whatever the shape of the routes is. The results are quite good. With only 256 MiB, about 2 million routes can be stored!

Routing rules Unless configured without CONFIG_IP_MULTIPLE_TABLES, Linux supports several routing tables and has a system of configurable rules to select the table to use. These rules can be configured with ip rule. By default, there are three of them:

$ ip rule show
0:      from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Linux will first lookup for a match in the local table. If it doesn t find one, it will lookup in the main table and at last resort, the default table.

Builtin tables The local table contains routes for local delivery:

$ ip route show table local
broadcast 127.0.0.0 dev lo proto kernel scope link src 127.0.0.1
local 127.0.0.0/8 dev lo proto kernel scope host src 127.0.0.1
local 127.0.0.1 dev lo proto kernel scope host src 127.0.0.1
broadcast 127.255.255.255 dev lo proto kernel scope link src 127.0.0.1
broadcast 192.168.117.0 dev eno1 proto kernel scope link src 192.168.117.55
local 192.168.117.55 dev eno1 proto kernel scope host src 192.168.117.55
broadcast 192.168.117.63 dev eno1 proto kernel scope link src 192.168.117.55

This table is populated automatically by the kernel when addresses are configured. Let s look at the three last lines. When the IP address 192.168.117.55 was configured on the eno1 interface, the kernel automatically added the appropriate routes:

• a route for 192.168.117.55 for local unicast delivery to the IP address,
• a route for 192.168.117.255 for broadcast delivery to the broadcast address,
• a route for 192.168.117.0 for broadcast delivery to the network address.

When 127.0.0.1 was configured on the loopback interface, the same kind of routes were added to the local table. However, a loopback address receives a special treatment and the kernel also adds the whole subnet to the local table. As a result, you can ping any IP in 127.0.0.0/8:

$ ping -c1 127.42.42.42
PING 127.42.42.42 (127.42.42.42) 56(84) bytes of data.
64 bytes from 127.42.42.42: icmp_seq=1 ttl=64 time=0.039 ms
--- 127.42.42.42 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.039/0.039/0.039/0.000 ms

The main table usually contains all the other routes:

$ ip route show table main
default via 192.168.117.1 dev eno1 proto static metric 100
192.168.117.0/26 dev eno1 proto kernel scope link src 192.168.117.55 metric 100

The default route has been configured by some DHCP daemon. The connected route (scope link) has been automatically added by the kernel (proto kernel) when configuring an IP address on the eno1 interface. The default table is empty and has little use. It has been kept when the current incarnation of advanced routing has been introduced in Linux 2.1.68 after a first tentative using classes in Linux 2.1.15⁶.

Performance Since Linux 4.1 (commit 0ddcf43d5d4a), when the set of rules is left unmodified, the main and local tables are merged and the lookup is done with this single table (and the default table if not empty). Moreover, since Linux 3.0 (commit f4530fa574df), without specific rules, there is no performance hit when enabling the support for multiple routing tables. However, as soon as you add new rules, some CPU cycles will be spent for each datagram to evaluate them. Here is a couple of graphs demonstrating the impact of routing rules on lookup times: For some reason, the relation is linear when the number of rules is between 1 and 100 but the slope increases noticeably past this threshold. The second graph highlights the negative impact of the first rule (about 30 ns). A common use of rules is to create virtual routers: interfaces are segregated into domains and when a datagram enters through an interface from domain A, it should use routing table A:

# ip rule add iif vlan457 table 10
# ip rule add iif vlan457 blackhole
# ip rule add iif vlan458 table 20
# ip rule add iif vlan458 blackhole

The blackhole rules may be removed if you are sure there is a default route in each routing table. For example, we add a blackhole default with a high metric to not override a regular default route:

# ip route add blackhole default metric 9999 table 10
# ip route add blackhole default metric 9999 table 20
# ip rule add iif vlan457 table 10
# ip rule add iif vlan458 table 20

To reduce the impact on performance when many interface-specific rules are used, interfaces can be attached to VRF instances and a single rule can be used to select the appropriate table:

# ip link add vrf-A type vrf table 10
# ip link set dev vrf-A up
# ip link add vrf-B type vrf table 20
# ip link set dev vrf-B up
# ip link set dev vlan457 master vrf-A
# ip link set dev vlan458 master vrf-B
# ip rule show
0:      from all lookup local
1000:   from all lookup [l3mdev-table]
32766:  from all lookup main
32767:  from all lookup default

The special l3mdev-table rule was automatically added when configuring the first VRF interface. This rule will select the routing table associated to the VRF owning the input (or output) interface. VRF was introduced in Linux 4.3 (commit 193125dbd8eb), the performance was greatly enhanced in Linux 4.8 (commit 7889681f4a6c) and the special routing rule was also introduced in Linux 4.8 (commit 96c63fa7393d, commit 1aa6c4f6b8cd). You can find more details about it in the kernel documentation.

Conclusion The takeaways from this article are:

• route lookup times hardly increase with the number of routes,
• densily packed /32 routes lead to amazingly fast route lookups,
• memory use is low (128 MiB par million routes),
• no optimization is done on routing rules.

---

1. The routing cache was subject to reasonably easy to launch denial of service attacks. It was also believed to not be efficient for high volume sites like Google but I have first-hand experience it was not the case for moderately high volume sites.
2. IP-address lookup using LC-tries , IEEE Journal on Selected Areas in Communications, 17(6):1083-1092, June 1999.
3. For internal nodes, the key_vector structure is embedded into a tnode structure. This structure contains information rarely used during lookup, notably the reference to the parent that is usually not needed for backtracking as Linux keeps the nearest candidate in a variable.
4. One leaf can contain several routes (struct fib_alias is a list). The number of prefixes can therefore be greater than the number of leaves. The system also keeps statistics about the distribution of the internal nodes relative to the number of bits they handle. In our example, all the three internal nodes are handling 2 bits.
5. The measurements are done in a virtual machine with one vCPU. The host is an Intel Core i5-4670K running at 3.7 GHz during the experiment (CPU governor was set to performance). The benchmark is single-threaded. It runs a warm-up phase, then executes about 100,000 timed iterations and keeps the median. Timings of individual runs are computed from the TSC.
6. Fun fact: the documentation of this first tentative of more flexible routing is still available in today s kernel tree and explains the usage of the default class .

• several packages have been merged, some are dropped (eg. texlive-htmlxml) and one new package (texlive-plain-generic) has been added
• luatex got updated to 1.0.4, and is now considered stable
• updmap and fmtutil now require either -sys or -user
• tlmgr got a shell mode (interactive/scripting interface) and a new feature to add arbitrary TEXMF trees (conf auxtrees)

When invoking this function, be careful not to interpolate arguments into the string run by the shell, such as Exec::shell(format!("sort ", filename)). Such code is prone to errors and, if filename comes from an untrusted source, to shell injection attacks. Instead, use Exec::cmd("sort").arg(filename).

fn copyright_fromgit(repo: &str) -> Result<Vec<String>>  
    let tempdir = TempDir::new_in(".", "debcargo")?;
    Exec::cmd("git")
     .args(&["clone", "--bare", repo, tempdir.path().to_str().unwrap()])
     .stdout(subprocess::NullFile)
     .stderr(subprocess::NullFile)
     .popen()?;
    let author_process =  
        Exec::shell(OsStr::new("git log --format=\"%an <%ae>\"")).cwd(tempdir.path())  
        Exec::shell(OsStr::new("sort -u"))
     .capture()?;
    let authors = author_process.stdout_str().trim().to_string();
    let authors: Vec<&str> = authors.split('\n').collect();
    let mut notices: Vec<String> = Vec::new();
    for author in &authors  
        let author_string = format!("--author= ", author);
        let first =  
            Exec::cmd("/usr/bin/git")
             .args(&["log", "--format=%ad",
                    "--date=format:%Y",
                    "--reverse",
                    &author_string])
             .cwd(tempdir.path())   Exec::shell(OsStr::new("head -n1"))
         .capture()?;
        let latest =  
            Exec::cmd("/usr/bin/git")
             .args(&["log", "--format=%ad", "--date=format:%Y", &author_string])
             .cwd(tempdir.path())   Exec::shell("head -n1")
         .capture()?;
        let start = i32::from_str(first.stdout_str().trim())?;
        let end = i32::from_str(latest.stdout_str().trim())?;
        let cnotice = match start.cmp(&end)  
            Ordering::Equal => format!(" ,  ", start, author),
            _ => format!(" - ,  ", start, end, author),
         ;
        notices.push(cnotice);
     
    Ok(notices)
 

** libs
Error in .shlib_internal(args) : 
  C++14 standard requested but CXX14 is not defined

#!/bin/bash
## Travis can let us run R 3.4.0 (from CRAN and the PPAs) but this R version
## does not know about C++14.  Even though we can select CXX_STD = C++14, R
## will fail as the version we use there was built in too old an environment,
## namely Ubuntu "trusty" 14.04.
##
## So we install g++-6 from another repo and rely on the fact that is
## defaults to C++14.  Sadly, we need R to not fail and hence, just on
## Travis, remove the C++14 instruction
if [[ "$ CI " == "true" ]]; then
    if [[ "$ TRAVIS " == "true" ]]; then 
        echo "** Overriding src/Makevars and removing C++14 on Travis only"
        sed -i 's CXX_STD = CXX14 ' src/Makevars
    fi
fi

• Chris Lamb: #864082 filed against fontconfig, forwarded upstream

• Adrian Bunk (4)
• Chris Lamb (1)
• Christoph Biedl (1)
• Niko Tyni (1)

• build: ensure that flock is available for make download (Felix Fietkau)
• include/toplevel: set env GIT_ASKPASS=/bin/true (Alexander 'lynxis' Couzens)

• Chris Lamb: Some code style improvements

• Build tar before downloading everything: On system without tar --sort=name we need to compile tar before downloading everything
• Set CONFIG_AUTOREMOVE to reduce required space
• Create a workaround for signing keys: LEDE signs the release with a signing key, but generates the signing key if it's not present. To have a reproducible release we need to take care of signing keys.
• openwrt_get_banner(): use staging_dir instead of build_dir because the former is persistent among the two builds.
• Don't build all packages to improve development speed for now.
• Only build one board instead of all boards. Reducing the build time improves developing speed. Once the image is reproducible we will enable more boards.
• Disable node_cleanup_tmpdirs

• Do full git reset/clean like Jenkins does
• hard code WORKSPACE dir names, as WORKSPACE cannot be generated from $0 as it's a temporary name.

• Remote scheduler:
  • English fix to error message.
  • Allow multiple architectures in one invocation.
  • Refactor: Break out a helper function. Rename variable to disambiguate with scheduling_args.message.
• Include timestamps in logs
• Set timestamps to second resolution (was millisecond by default).

• Improvements to the breakages page:
  • List broken packages and diffoscope problems first, and t.r-b.o problems last.
  • Reword, drop 'caused by'.
• Add niceness to our list of variations, running with niceness of 11 for the first build and niceness of 10 for the second one. Thanks to Vagrant for the idea.
• Automatic scheduler:
  • Reschedule after 12h packages that failed with error 404
  • Run scheduler every 3h instead of every 6h
• Add basic README about the infrastructure and merge Vagrants notes about his console host.