tjh.dev
1# Assert that FILE exists and is executable
2#
3# assertExecutable FILE
4assertExecutable() {
5 local file="$1"
6 [[ -f "$file" && -x "$file" ]] || \
7 die "Cannot wrap '$file' because it is not an executable file"
8}
9
10# construct an executable file that wraps the actual executable
11# makeWrapper EXECUTABLE OUT_PATH ARGS
12
13# ARGS:
14# --argv0 NAME : set name of executed process to NAME
15# (otherwise it’s called …-wrapped)
16# --set VAR VAL : add VAR with value VAL to the executable’s
17# environment
18# --set-default VAR VAL : like --set, but only adds VAR if not already set in
19# the environment
20# --unset VAR : remove VAR from the environment
21# --run COMMAND : run command before the executable
22# --add-flags FLAGS : add FLAGS to invocation of executable
23
24# --prefix ENV SEP VAL : suffix/prefix ENV with VAL, separated by SEP
25# --suffix
26# --prefix-each ENV SEP VALS : like --prefix, but VALS is a list
27# --suffix-each ENV SEP VALS : like --suffix, but VALS is a list
28# --prefix-contents ENV SEP FILES : like --suffix-each, but contents of FILES
29# are read first and used as VALS
30# --suffix-contents
31makeWrapper() {
32 local original="$1"
33 local wrapper="$2"
34 local params varName value command separator n fileNames
35 local argv0 flagsBefore flags
36
37 assertExecutable "$original"
38
39 mkdir -p "$(dirname "$wrapper")"
40
41 echo "#! @shell@ -e" > "$wrapper"
42
43 params=("$@")
44 for ((n = 2; n < ${#params[*]}; n += 1)); do
45 p="${params[$n]}"
46
47 if [[ "$p" == "--set" ]]; then
48 varName="${params[$((n + 1))]}"
49 value="${params[$((n + 2))]}"
50 n=$((n + 2))
51 echo "export $varName=${value@Q}" >> "$wrapper"
52 elif [[ "$p" == "--set-default" ]]; then
53 varName="${params[$((n + 1))]}"
54 value="${params[$((n + 2))]}"
55 n=$((n + 2))
56 echo "export $varName=\${$varName-${value@Q}}" >> "$wrapper"
57 elif [[ "$p" == "--unset" ]]; then
58 varName="${params[$((n + 1))]}"
59 n=$((n + 1))
60 echo "unset $varName" >> "$wrapper"
61 elif [[ "$p" == "--run" ]]; then
62 command="${params[$((n + 1))]}"
63 n=$((n + 1))
64 echo "$command" >> "$wrapper"
65 elif [[ ("$p" == "--suffix") || ("$p" == "--prefix") ]]; then
66 varName="${params[$((n + 1))]}"
67 separator="${params[$((n + 2))]}"
68 value="${params[$((n + 3))]}"
69 n=$((n + 3))
70 if test -n "$value"; then
71 if test "$p" = "--suffix"; then
72 echo "export $varName=\$$varName\${$varName:+${separator@Q}}${value@Q}" >> "$wrapper"
73 else
74 echo "export $varName=${value@Q}\${$varName:+${separator@Q}}\$$varName" >> "$wrapper"
75 fi
76 fi
77 elif [[ "$p" == "--prefix-each" ]]; then
78 varName="${params[$((n + 1))]}"
79 separator="${params[$((n + 2))]}"
80 values="${params[$((n + 3))]}"
81 n=$((n + 3))
82 for value in $values; do
83 echo "export $varName=${value@Q}\${$varName:+${separator@Q}}\$$varName" >> "$wrapper"
84 done
85 elif [[ "$p" == "--suffix-each" ]]; then
86 varName="${params[$((n + 1))]}"
87 separator="${params[$((n + 2))]}"
88 values="${params[$((n + 3))]}"
89 n=$((n + 3))
90 for value in $values; do
91 echo "export $varName=\$$varName\${$varName:+$separator}${value@Q}" >> "$wrapper"
92 done
93 elif [[ ("$p" == "--suffix-contents") || ("$p" == "--prefix-contents") ]]; then
94 varName="${params[$((n + 1))]}"
95 separator="${params[$((n + 2))]}"
96 fileNames="${params[$((n + 3))]}"
97 n=$((n + 3))
98 for fileName in $fileNames; do
99 contents="$(cat "$fileName")"
100 if test "$p" = "--suffix-contents"; then
101 echo "export $varName=\$$varName\${$varName:+$separator}${contents@Q}" >> "$wrapper"
102 else
103 echo "export $varName=${contents@Q}\${$varName:+$separator}\$$varName" >> "$wrapper"
104 fi
105 done
106 elif [[ "$p" == "--add-flags" ]]; then
107 flags="${params[$((n + 1))]}"
108 n=$((n + 1))
109 flagsBefore="$flagsBefore $flags"
110 elif [[ "$p" == "--argv0" ]]; then
111 argv0="${params[$((n + 1))]}"
112 n=$((n + 1))
113 else
114 die "makeWrapper doesn't understand the arg $p"
115 fi
116 done
117
118 echo exec ${argv0:+-a \"$argv0\"} \""$original"\" \
119 "$flagsBefore" '"$@"' >> "$wrapper"
120
121 chmod +x "$wrapper"
122}
123
124addSuffix() {
125 suffix="$1"
126 shift
127 for name in "$@"; do
128 echo "$name$suffix"
129 done
130}
131
132filterExisting() {
133 for fn in "$@"; do
134 if test -e "$fn"; then
135 echo "$fn"
136 fi
137 done
138}
139
140# Syntax: wrapProgram <PROGRAM> <MAKE-WRAPPER FLAGS...>
141wrapProgram() {
142 local prog="$1"
143 local hidden
144
145 assertExecutable "$prog"
146
147 hidden="$(dirname "$prog")/.$(basename "$prog")"-wrapped
148 while [ -e "$hidden" ]; do
149 hidden="${hidden}_"
150 done
151 mv "$prog" "$hidden"
152 # Silence warning about unexpanded $0:
153 # shellcheck disable=SC2016
154 makeWrapper "$hidden" "$prog" --argv0 '$0' "${@:2}"
155}