1 |
v2 |
2 |
-mike |
3 |
|
4 |
# Copyright 1999-2012 Gentoo Foundation |
5 |
# Distributed under the terms of the GNU General Public License v2 |
6 |
# $Header: $ |
7 |
|
8 |
# @ECLASS: multiprocessing.eclass |
9 |
# @MAINTAINER: |
10 |
# base-system@g.o |
11 |
# @AUTHOR: |
12 |
# Brian Harring <ferringb@g.o> |
13 |
# Mike Frysinger <vapier@g.o> |
14 |
# @BLURB: parallelization with bash (wtf?) |
15 |
# @DESCRIPTION: |
16 |
# The multiprocessing eclass contains a suite of functions that allow ebuilds |
17 |
# to quickly run things in parallel using shell code. |
18 |
# @EXAMPLE: |
19 |
# |
20 |
# @CODE |
21 |
# # First initialize things: |
22 |
# multijob_init |
23 |
# |
24 |
# # Then hash a bunch of files in parallel: |
25 |
# for n in {0..20} ; do |
26 |
# multijob_child_init md5sum data.${n} > data.${n} |
27 |
# done |
28 |
# |
29 |
# # Then wait for all the children to finish: |
30 |
# multijob_finish |
31 |
# @CODE |
32 |
|
33 |
if [[ ${___ECLASS_ONCE_MULTIPROCESSING} != "recur -_+^+_- spank" ]] ; then |
34 |
___ECLASS_ONCE_MULTIPROCESSING="recur -_+^+_- spank" |
35 |
|
36 |
# @FUNCTION: makeopts_jobs |
37 |
# @USAGE: [${MAKEOPTS}] |
38 |
# @DESCRIPTION: |
39 |
# Searches the arguments (defaults to ${MAKEOPTS}) and extracts the jobs number |
40 |
# specified therein. Useful for running non-make tools in parallel too. |
41 |
# i.e. if the user has MAKEOPTS=-j9, this will echo "9" -- we can't return the |
42 |
# number as bash normalizes it to [0, 255]. If the flags haven't specified a |
43 |
# -j flag, then "1" is shown as that is the default `make` uses. Since there's |
44 |
# no way to represent infinity, we return 999 if the user has -j without a number. |
45 |
makeopts_jobs() { |
46 |
[[ $# -eq 0 ]] && set -- ${MAKEOPTS} |
47 |
# This assumes the first .* will be more greedy than the second .* |
48 |
# since POSIX doesn't specify a non-greedy match (i.e. ".*?"). |
49 |
local jobs=$(echo " $* " | sed -r -n \ |
50 |
-e 's:.*[[:space:]](-j|--jobs[=[:space:]])[[:space:]]*([0-9]+).*:\2:p' \ |
51 |
-e 's:.*[[:space:]](-j|--jobs)[[:space:]].*:999:p') |
52 |
echo ${jobs:-1} |
53 |
} |
54 |
|
55 |
# @FUNCTION: redirect_alloc_fd |
56 |
# @USAGE: <var> <file> [redirection] |
57 |
# @DESCRIPTION: |
58 |
# Find a free fd and redirect the specified file via it. Store the new |
59 |
# fd in the specified variable. Useful for the cases where we don't care |
60 |
# about the exact fd #. |
61 |
redirect_alloc_fd() { |
62 |
local var=$1 file=$2 redir=${3:-"<>"} |
63 |
|
64 |
if [[ $(( (BASH_VERSINFO[0] << 8) + BASH_VERSINFO[1] )) -ge $(( (4 << 8) + 1 )) ]] ; then |
65 |
# Newer bash provides this functionality. |
66 |
eval "exec {${var}}${redir}'${file}'" |
67 |
else |
68 |
# Need to provide the functionality ourselves. |
69 |
local fd=10 |
70 |
while :; do |
71 |
if [[ ! -L /dev/fd/${fd} ]] ; then |
72 |
eval "exec ${fd}${redir}'${file}'" && break |
73 |
fi |
74 |
[[ ${fd} -gt 1024 ]] && return 1 # sanity |
75 |
: $(( ++fd )) |
76 |
done |
77 |
: $(( ${var} = fd )) |
78 |
fi |
79 |
} |
80 |
|
81 |
# @FUNCTION: multijob_init |
82 |
# @USAGE: [${MAKEOPTS}] |
83 |
# @DESCRIPTION: |
84 |
# Setup the environment for executing code in parallel. |
85 |
# You must call this before any other multijob function. |
86 |
multijob_init() { |
87 |
# When something goes wrong, try to wait for all the children so we |
88 |
# don't leave any zombies around. |
89 |
has wait ${EBUILD_DEATH_HOOKS} || EBUILD_DEATH_HOOKS+=" wait" |
90 |
|
91 |
# Setup a pipe for children to write their pids to when they finish. |
92 |
mj_control_pipe="${T}/multijob.pipe" |
93 |
mkfifo "${mj_control_pipe}" |
94 |
redirect_alloc_fd mj_control_fd "${mj_control_pipe}" |
95 |
rm -f "${mj_control_pipe}" |
96 |
|
97 |
# See how many children we can fork based on the user's settings. |
98 |
mj_max_jobs=$(makeopts_jobs "$@") |
99 |
mj_num_jobs=0 |
100 |
} |
101 |
|
102 |
# @FUNCTION: multijob_child_init |
103 |
# @USAGE: [command to run in background] |
104 |
# @DESCRIPTION: |
105 |
# This function has two forms. You can use it to execute a simple command |
106 |
# in the background (and it takes care of everything else), or you must |
107 |
# call this first thing in your forked child process. |
108 |
# |
109 |
# @CODE |
110 |
# # 1st form: pass the command line as arguments: |
111 |
# multijob_child_init ls /dev |
112 |
# |
113 |
# # 2nd form: execute multiple stuff in the background: |
114 |
# ( |
115 |
# multijob_child_init |
116 |
# out=`ls` |
117 |
# if echo "${out}" | grep foo ; then |
118 |
# echo "YEAH" |
119 |
# fi |
120 |
# ) & |
121 |
# multijob_post_fork |
122 |
# @CODE |
123 |
multijob_child_init() { |
124 |
if [[ $# -eq 0 ]] ; then |
125 |
trap 'echo ${BASHPID} $? >&'${mj_control_fd} EXIT |
126 |
trap 'exit 1' INT TERM |
127 |
else |
128 |
( multijob_child_init ; "$@" ) & |
129 |
multijob_post_fork |
130 |
fi |
131 |
} |
132 |
|
133 |
# @FUNCTION: multijob_post_fork |
134 |
# @DESCRIPTION: |
135 |
# You must call this in the parent process after forking a child process. |
136 |
# If the parallel limit has been hit, it will wait for one child to finish |
137 |
# and return the its exit status. |
138 |
multijob_post_fork() { |
139 |
[[ $# -eq 0 ]] || die "${FUNCNAME} takes no arguments" |
140 |
|
141 |
: $(( ++mj_num_jobs )) |
142 |
if [[ ${mj_num_jobs} -ge ${mj_max_jobs} ]] ; then |
143 |
multijob_finish_one |
144 |
fi |
145 |
return $? |
146 |
} |
147 |
|
148 |
# @FUNCTION: multijob_finish_one |
149 |
# @DESCRIPTION: |
150 |
# Wait for a single process to exit and return its exit code. |
151 |
multijob_finish_one() { |
152 |
[[ $# -eq 0 ]] || die "${FUNCNAME} takes no arguments" |
153 |
|
154 |
local pid ret |
155 |
read -r -u ${mj_control_fd} pid ret || die |
156 |
: $(( --mj_num_jobs )) |
157 |
return ${ret} |
158 |
} |
159 |
|
160 |
# @FUNCTION: multijob_finish |
161 |
# @DESCRIPTION: |
162 |
# Wait for all pending processes to exit and return the bitwise or |
163 |
# of all their exit codes. |
164 |
multijob_finish() { |
165 |
local ret=0 |
166 |
while [[ ${mj_num_jobs} -gt 0 ]] ; do |
167 |
multijob_finish_one |
168 |
: $(( ret |= $? )) |
169 |
done |
170 |
# Let bash clean up its internal child tracking state. |
171 |
wait |
172 |
|
173 |
# Do this after reaping all the children. |
174 |
[[ $# -eq 0 ]] || die "${FUNCNAME} takes no arguments" |
175 |
|
176 |
return ${ret} |
177 |
} |
178 |
|
179 |
fi |