Use directory in /tmp for temporary files

Using a standard directory for temporaries buys us performance when the
user wants it (has configured tmpfs for /tmp) and configurability
(accepts TMPDIR=).

Moving /pack to a temporary directory gives safe concurrent remote
repacks.

diff --git a/git-remote-gcrypt b/git-remote-gcrypt
index 9bd7bc26e40ac6748ae1f886de2afe01e969f758..9c5b59931a97cb872419ccd10fce4dbea9363fe2 100755 (executable)
--- a/git-remote-gcrypt
+++ b/git-remote-gcrypt
@@ -22,7 +22,6 @@ set -u # nounset
 set -f # noglob
 set -C # noclobber
 
-Localdir="${GIT_DIR:=.git}/remote-gcrypt"
 export GITCEPTION="${GITCEPTION:-}+" # Reuse $Gref except when stacked
 Gref="refs/gcrypt/gitception$GITCEPTION"
 Gref_rbranch="refs/heads/master"
@@ -34,6 +33,9 @@ Hex40=$Hex40$Hex40$Hex40$Hex40$Hex40$Hex40$Hex40$Hex40
 Hex40=$Hex40$Hex40$Hex40$Hex40$Hex40 # Match SHA-1 hexdigest
 
 Did_find_repo=  # yes for connected, no for no repo
+Localdir="${GIT_DIR:=.git}/remote-gcrypt"
+Tempdir=
+
 Repoid=
 Refslist=
 Packlist=
@@ -357,12 +359,6 @@ gpg_hash()
        xecho "${hash_%:}"
 }
 
-# $1 type
-tempname()
-{
-       xecho "$Localdir/tmp_$1_.$$"
-}
-
 # Pass the branch/ref by pipe to git
 safe_git_rev_parse()
 {
@@ -505,7 +501,7 @@ ensure_connected()
                Repoid=$(git config "remote.$r_name.gcrypt-id" || :)
 
 
-       tmp_manifest=$(tempname maniF)
+       tmp_manifest="$Tempdir/maniF"
        GET "$URL" "$Manifestfile" "$tmp_manifest" 2>/dev/null || {
                echo_info "Repository not found: $URL"
                return 0
@@ -551,7 +547,7 @@ ensure_connected()
 get_verify_decrypt_pack()
 {
        local rcv_id= tmp_encrypted=
-       tmp_encrypted=$(tempname packF)
+       tmp_encrypted="$Tempdir/packF"
        GET "$URL" "$2" "$tmp_encrypted" &&
        rcv_id=$(gpg_hash "$1" < "$tmp_encrypted") &&
        iseq "$rcv_id" "$2" || echo_die "Packfile $2 does not match digest!"
@@ -615,8 +611,7 @@ repack_if_needed()
        fi
        echo_info "Repacking remote $NAME, ..."
 
-       rm -r -f "$Localdir/pack"
-       mkdir -p "$Localdir/pack"
+       mkdir "$Tempdir/pack"
 
        # Split packages to keep and to repack
        if isnonnull "$Keeplist"; then
@@ -631,9 +626,9 @@ $Keeplist
 EOF
        fi
 
-       xfeed "$r_del_list" get_pack_files "$Localdir/pack/"
+       xfeed "$r_del_list" get_pack_files "$Tempdir/pack/"
 
-       (set +f; git verify-pack -v "$Localdir"/pack/*.idx ||
+       (set +f; git verify-pack -v "$Tempdir"/pack/*.idx ||
         echo_kill "git verify-pack failed!") |
                grep -E '^[0-9a-f]{40}' | cut -f 1 -d ' '
 
@@ -729,8 +724,8 @@ do_push()
 $1
 EOF
 
-       tmp_encrypted=$(tempname packP)
-       tmp_objlist=$(tempname objlP)
+       tmp_encrypted="$Tempdir/packP"
+       tmp_objlist="$Tempdir/objlP"
 
        {
                xfeed "$r_revlist" git rev-list --objects --stdin --
@@ -743,7 +738,7 @@ EOF
                key_=$(genkey "$Packkey_bytes")
                pack_id=$(\
                        {
-                               GIT_ALTERNATE_OBJECT_DIRECTORIES=$Localdir \
+                               GIT_ALTERNATE_OBJECT_DIRECTORIES=$Tempdir \
                                git pack-objects --stdout < "$tmp_objlist" ||
                                echo_kill "git pack-objects failed!"
                        } | {
@@ -762,7 +757,7 @@ EOF
        echo_info "Encrypting to: $Recipients"
        echo_info "Requesting manifest signature"
 
-       tmp_manifest=$(tempname maniP)
+       tmp_manifest="$Tempdir/maniP"
        PRIVENCRYPT "$Recipients" > "$tmp_manifest" <<EOF
 $Refslist
 $Packlist
@@ -786,7 +781,6 @@ EOF
 
        # Delete packs
        if isnonnull "$r_pack_delete"; then
-               rm -r -f "$Localdir/pack"
                REMOVE "$URL" "$(xecho "$r_pack_delete" | \
                        while IFS=': ' read -r _ _ pack_
                        do
@@ -810,23 +804,30 @@ EOF
 
 cleanup_tmpfiles()
 {
-       (set +f; rm -f "$Localdir"/tmp_*".$$" >&2)
+       if isnonnull "${Tempdir%%*."$$"}"; then
+               echo_die "Unexpected Tempdir value: $Tempdir"
+       fi
+       rm -r -f -- "${Tempdir}" >&2
 }
 
 # handle git-remote-helpers protocol
 gcrypt_main_loop()
 {
-       local input_= input_inner= r_args=
+       local input_= input_inner= r_args= temp_key=
 
        NAME=$1  # Remote name
        URL=$2   # Remote URL
 
+       mkdir -p "$Localdir"
+
+       # Set up a subdirectory in /tmp
+       temp_key=$(genkey 9 | tr '/' _)
+       Tempdir="${TMPDIR:-/tmp}/git-remote-gcrypt-${temp_key}.$$"
+       mkdir -m 700 "${Tempdir}"
+
        trap cleanup_tmpfiles EXIT
        trap 'exit 1' 1 2 3 15
 
-       mkdir -p "$Localdir"
-       cleanup_tmpfiles
-
        echo_info "Development version -- Repository format MAY CHANGE"
 
        while read input_