lix/src/fstate.cc

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#include <map>
#include <iostream>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>
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#include <fcntl.h>
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#include "fstate.hh"
#include "globals.hh"
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#include "store.hh"
#include "db.hh"
#include "references.hh"
/* A Unix environment is a mapping from strings to strings. */
typedef map<string, string> Environment;
class AutoDelete
{
string path;
public:
AutoDelete(const string & p) : path(p)
{
}
~AutoDelete()
{
deletePath(path);
}
};
/* Run a program. */
static void runProgram(const string & program, Environment env)
{
/* Create a log file. */
string logFileName = nixLogDir + "/run.log";
/* !!! auto-pclose on exit */
FILE * logFile = popen(("tee -a " + logFileName + " >&2").c_str(), "w"); /* !!! escaping */
if (!logFile)
throw SysError(format("creating log file `%1%'") % logFileName);
/* Create a temporary directory where the build will take
place. */
static int counter = 0;
string tmpDir = (format("/tmp/nix-%1%-%2%") % getpid() % counter++).str();
if (mkdir(tmpDir.c_str(), 0777) == -1)
throw SysError(format("creating directory `%1%'") % tmpDir);
AutoDelete delTmpDir(tmpDir);
/* Fork a child to build the package. */
pid_t pid;
switch (pid = fork()) {
case -1:
throw SysError("unable to fork");
case 0:
try { /* child */
if (chdir(tmpDir.c_str()) == -1)
throw SysError(format("changing into to `%1%'") % tmpDir);
/* Fill in the environment. We don't bother freeing
the strings, since we'll exec or die soon
anyway. */
const char * env2[env.size() + 1];
int i = 0;
for (Environment::iterator it = env.begin();
it != env.end(); it++, i++)
env2[i] = (new string(it->first + "=" + it->second))->c_str();
env2[i] = 0;
/* Dup the log handle into stderr. */
if (dup2(fileno(logFile), STDERR_FILENO) == -1)
throw SysError("cannot pipe standard error into log file");
/* Dup stderr to stdin. */
if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1)
throw SysError("cannot dup stderr into stdout");
/* Make the program executable. !!! hack. */
if (chmod(program.c_str(), 0755))
throw SysError("cannot make program executable");
/* Execute the program. This should not return. */
execle(program.c_str(), baseNameOf(program).c_str(), 0, env2);
throw SysError(format("unable to execute %1%") % program);
} catch (exception & e) {
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cerr << format("build error: %1%\n") % e.what();
}
_exit(1);
}
/* parent */
/* Close the logging pipe. Note that this should not cause
the logger to exit until builder exits (because the latter
has an open file handle to the former). */
pclose(logFile);
/* Wait for the child to finish. */
int status;
if (waitpid(pid, &status, 0) != pid)
throw Error("unable to wait for child");
if (!WIFEXITED(status) || WEXITSTATUS(status) != 0)
throw Error("unable to build package");
}
/* Throw an exception if the given platform string is not supported by
the platform we are executing on. */
static void checkPlatform(const string & platform)
{
if (platform != thisSystem)
throw Error(format("a `%1%' is required, but I am a `%2%'")
% platform % thisSystem);
}
string printTerm(ATerm t)
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{
char * s = ATwriteToString(t);
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return s;
}
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Error badTerm(const format & f, ATerm t)
{
return Error(format("%1%, in `%2%'") % f.str() % printTerm(t));
}
Hash hashTerm(ATerm t)
{
return hashString(printTerm(t));
}
FState hash2fstate(Hash hash)
{
return ATmake("Include(<str>)", ((string) hash).c_str());
}
ATerm termFromId(const FSId & id, string * p)
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{
string path = expandId(id);
if (p) *p = path;
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ATerm t = ATreadFromNamedFile(path.c_str());
if (!t) throw Error(format("cannot read aterm from `%1%'") % path);
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return t;
}
FSId writeTerm(ATerm t, const string & suffix, string * p)
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{
FSId id = hashTerm(t);
string path = canonPath(nixStore + "/" +
(string) id + suffix + ".nix");
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if (!ATwriteToNamedTextFile(t, path.c_str()))
throw Error(format("cannot write aterm %1%") % path);
registerPath(path, id);
if (p) *p = path;
return id;
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}
void registerSuccessor(const FSId & id1, const FSId & id2)
{
setDB(nixDB, dbSuccessors, id1, id2);
}
static FSId storeSuccessor(const FSId & id1, FState sc)
{
FSId id2 = writeTerm(sc, "-s-" + (string) id1, 0);
registerSuccessor(id1, id2);
return id2;
}
#if 0
static FState realise(FState fs, StringSet & paths)
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{
char * s1, * s2, * s3;
Content content;
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ATermList refs, ins, bnds;
/* First repeatedly try to substitute $fs$ by any known successors
in order to speed up the rewrite process. */
{
string fsHash, scHash;
while (queryDB(nixDB, dbSuccessors, fsHash = hashTerm(fs), scHash)) {
debug(format("successor %1% -> %2%") % (string) fsHash % scHash);
string path;
FState fs2 = termFromHash(parseHash(scHash), &path);
paths.insert(path);
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if (fs == fs2) {
debug(format("successor cycle detected in %1%") % printTerm(fs));
break;
}
fs = fs2;
}
}
/* Fall through. */
if (ATmatch(fs, "Include(<str>)", &s1)) {
string path;
fs = termFromHash(parseHash(s1), &path);
paths.insert(path);
return realise(fs, paths);
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}
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else if (ATmatch(fs, "Path(<str>, <term>, [<list>])", &s1, &content, &refs)) {
string path(s1);
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msg(format("realising atomic path %1%") % path);
Nest nest(true);
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if (path[0] != '/')
throw Error(format("path `%1% is not absolute") % path);
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/* Realise referenced paths. */
ATermList refs2 = ATempty;
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while (!ATisEmpty(refs)) {
refs2 = ATinsert(refs2, realise(ATgetFirst(refs), paths));
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refs = ATgetNext(refs);
}
refs2 = ATreverse(refs2);
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if (!ATmatch(content, "Hash(<str>)", &s1))
throw badTerm("hash expected", content);
Hash hash = parseHash(s1);
/* Normal form. */
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ATerm nf = ATmake("Path(<str>, <term>, <term>)",
path.c_str(), content, refs2);
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/* Register the normal form. */
nf = storeSuccessor(fs, nf, paths);
/* Expand the hash into the target path. */
expandHash(hash, path);
return nf;
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}
else if (ATmatch(fs, "Derive(<str>, <str>, [<list>], <str>, [<list>])",
&s1, &s2, &ins, &s3, &bnds))
{
string platform(s1), builder(s2), outPath(s3);
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msg(format("realising derivate path %1%") % outPath);
Nest nest(true);
checkPlatform(platform);
/* Realise inputs. */
Strings inPaths;
ATermList ins2 = ATempty;
while (!ATisEmpty(ins)) {
FState in = realise(ATgetFirst(ins), paths);
inPaths.push_back(fstatePath(in));
ins2 = ATinsert(ins2, in);
ins = ATgetNext(ins);
}
ins = ATreverse(ins2);
/* Build the environment. */
Environment env;
while (!ATisEmpty(bnds)) {
ATerm bnd = ATgetFirst(bnds);
if (!ATmatch(bnd, "(<str>, <str>)", &s1, &s2))
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throw badTerm("tuple of strings expected", bnd);
env[s1] = s2;
bnds = ATgetNext(bnds);
}
/* Check whether the target already exists. */
if (pathExists(outPath))
deleteFromStore(outPath);
// throw Error(format("path %1% already exists") % outPath);
/* Run the builder. */
runProgram(builder, env);
/* Check whether the result was created. */
if (!pathExists(outPath))
throw Error(format("program %1% failed to create a result in %2%")
% builder % outPath);
#if 0
/* Remove write permission from the value. */
int res = system(("chmod -R -w " + targetPath).c_str()); // !!! escaping
if (WEXITSTATUS(res) != 0)
throw Error("cannot remove write permission from " + targetPath);
#endif
/* Hash the result. */
Hash outHash = hashPath(outPath);
/* Register targetHash -> targetPath. !!! this should be in
values.cc. */
registerPath(outPath, outHash);
/* Filter out inputs that are not referenced in the output. */
for (Strings::iterator i = inPaths.begin();
i != inPaths.end(); i++)
debug(format("in: %1%") % *i);
Strings outPaths = filterReferences(outPath, inPaths);
for (Strings::iterator i = outPaths.begin();
i != outPaths.end(); i++)
debug(format("out: %1%") % *i);
ins2 = ATempty;
while (!ATisEmpty(ins)) {
FState in = ATgetFirst(ins);
string path = fstatePath(in);
for (Strings::iterator i = outPaths.begin();
i != outPaths.end(); i++)
if (path.find(*i) != string::npos) {
debug(format("out2: %1%") % path);
ins2 = ATinsert(ins2, in);
}
ins = ATgetNext(ins);
}
ins = ATreverse(ins2);
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/* Register the normal form of fs. */
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FState nf = ATmake("Path(<str>, Hash(<str>), <term>)",
outPath.c_str(), ((string) outHash).c_str(), ins);
nf = storeSuccessor(fs, nf, paths);
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return nf;
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}
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throw badTerm("bad fstate expression", fs);
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}
FState realiseFState(FState fs, StringSet & paths)
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{
return realise(fs, paths);
}
string fstatePath(FState fs)
{
char * s1, * s2, * s3;
FState e1, e2;
if (ATmatch(fs, "Path(<str>, <term>, [<list>])", &s1, &e1, &e2))
return s1;
else if (ATmatch(fs, "Derive(<str>, <str>, [<list>], <str>, [<list>])",
&s1, &s2, &e1, &s3, &e2))
return s3;
else if (ATmatch(fs, "Include(<str>)", &s1))
return fstatePath(termFromHash(parseHash(s1)));
else
return "";
}
void fstateRefs2(FState fs, StringSet & paths)
{
char * s1, * s2, * s3;
FState e1, e2;
ATermList refs, ins;
if (ATmatch(fs, "Path(<str>, <term>, [<list>])", &s1, &e1, &refs)) {
paths.insert(s1);
while (!ATisEmpty(refs)) {
fstateRefs2(ATgetFirst(refs), paths);
refs = ATgetNext(refs);
}
}
else if (ATmatch(fs, "Derive(<str>, <str>, [<list>], <str>, [<list>])",
&s1, &s2, &ins, &s3, &e2))
{
while (!ATisEmpty(ins)) {
fstateRefs2(ATgetFirst(ins), paths);
ins = ATgetNext(ins);
}
}
else if (ATmatch(fs, "Include(<str>)", &s1))
fstateRefs2(termFromHash(parseHash(s1)), paths);
else throw badTerm("bad fstate expression", fs);
}
void fstateRefs(FState fs, StringSet & paths)
{
fstateRefs2(fs, paths);
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}
#endif
static void parseIds(ATermList ids, FSIds & out)
{
while (!ATisEmpty(ids)) {
char * s;
ATerm id = ATgetFirst(ids);
if (!ATmatch(id, "<str>", &s))
throw badTerm("not an id", id);
out.push_back(parseHash(s));
debug(s);
ids = ATgetNext(ids);
}
}
/* Parse a slice. */
static Slice parseSlice(FState fs)
{
Slice slice;
ATermList roots, elems;
if (!ATmatch(fs, "Slice([<list>], [<list>])", &roots, &elems))
throw badTerm("not a slice", fs);
parseIds(roots, slice.roots);
while (!ATisEmpty(elems)) {
char * s1, * s2;
ATermList refs;
ATerm t = ATgetFirst(elems);
if (!ATmatch(t, "(<str>, <str>, [<list>])", &s1, &s2, &refs))
throw badTerm("not a slice element", t);
SliceElem elem;
elem.path = s1;
elem.id = parseHash(s2);
parseIds(refs, elem.refs);
slice.elems.push_back(elem);
elems = ATgetNext(elems);
}
return slice;
}
static ATermList unparseIds(const FSIds & ids)
{
ATermList l = ATempty;
for (FSIds::const_iterator i = ids.begin();
i != ids.end(); i++)
l = ATinsert(l,
ATmake("<str>", ((string) *i).c_str()));
return ATreverse(l);
}
static FState unparseSlice(const Slice & slice)
{
ATermList roots = unparseIds(slice.roots);
ATermList elems = ATempty;
for (SliceElems::const_iterator i = slice.elems.begin();
i != slice.elems.end(); i++)
elems = ATinsert(elems,
ATmake("(<str>, <str>, <term>)",
i->path.c_str(),
((string) i->id).c_str(),
unparseIds(i->refs)));
return ATmake("Slice(<term>, <term>)", roots, elems);
}
typedef set<FSId> FSIdSet;
Slice normaliseFState(FSId id)
{
debug(format("normalising fstate"));
Nest nest(true);
/* Try to substitute $id$ by any known successors in order to
speed up the rewrite process. */
string idSucc;
while (queryDB(nixDB, dbSuccessors, id, idSucc)) {
debug(format("successor %1% -> %2%") % (string) id % idSucc);
id = parseHash(idSucc);
}
/* Get the fstate expression. */
FState fs = termFromId(id);
/* Already in normal form (i.e., a slice)? */
if (ATgetType(fs) == AT_APPL &&
(string) ATgetName(ATgetAFun(fs)) == "Slice")
return parseSlice(fs);
/* Then we it's a Derive node. */
ATermList outs, ins, bnds;
char * builder;
char * platform;
if (!ATmatch(fs, "Derive([<list>], [<list>], <str>, <str>, [<list>])",
&outs, &ins, &builder, &platform, &bnds))
throw badTerm("not a derive", fs);
/* Right platform? */
checkPlatform(platform);
/* Realise inputs (and remember all input paths). */
FSIds inIds;
parseIds(ins, inIds);
typedef map<string, SliceElem> ElemMap;
ElemMap inMap;
for (FSIds::iterator i = inIds.begin(); i != inIds.end(); i++) {
Slice slice = normaliseFState(*i);
realiseSlice(slice);
for (SliceElems::iterator j = slice.elems.begin();
j != slice.elems.end(); j++)
inMap[j->path] = *j;
}
Strings inPaths;
for (ElemMap::iterator i = inMap.begin(); i != inMap.end(); i++)
inPaths.push_back(i->second.path);
/* Build the environment. */
Environment env;
while (!ATisEmpty(bnds)) {
char * s1, * s2;
ATerm bnd = ATgetFirst(bnds);
if (!ATmatch(bnd, "(<str>, <str>)", &s1, &s2))
throw badTerm("tuple of strings expected", bnd);
env[s1] = s2;
bnds = ATgetNext(bnds);
}
/* Check that none of the output paths exist. */
typedef pair<string, FSId> OutPath;
list<OutPath> outPaths;
while (!ATisEmpty(outs)) {
ATerm t = ATgetFirst(outs);
char * s1, * s2;
if (!ATmatch(t, "(<str>, <str>)", &s1, &s2))
throw badTerm("string expected", t);
outPaths.push_back(OutPath(s1, parseHash(s2)));
inPaths.push_back(s1);
outs = ATgetNext(outs);
}
for (list<OutPath>::iterator i = outPaths.begin();
i != outPaths.end(); i++)
if (pathExists(i->first))
throw Error(format("path `%1%' exists") % i->first);
/* Run the builder. */
runProgram(builder, env);
Slice slice;
/* Check whether the output paths were created, and register each
one. */
FSIdSet used;
for (list<OutPath>::iterator i = outPaths.begin();
i != outPaths.end(); i++)
{
string path = i->first;
if (!pathExists(path))
throw Error(format("path `%1%' does not exist") % path);
registerPath(path, i->second);
slice.roots.push_back(i->second);
Strings refs = filterReferences(path, inPaths);
SliceElem elem;
elem.path = path;
elem.id = i->second;
for (Strings::iterator j = refs.begin(); j != refs.end(); j++) {
ElemMap::iterator k;
if ((k = inMap.find(*j)) != inMap.end()) {
elem.refs.push_back(k->second.id);
used.insert(k->second.id);
} else abort(); /* fix! check in created paths */
}
slice.elems.push_back(elem);
}
for (ElemMap::iterator i = inMap.begin();
i != inMap.end(); i++)
{
FSIdSet::iterator j = used.find(i->second.id);
if (j == used.end())
debug(format("NOT referenced: `%1%'") % i->second.path);
else {
debug(format("referenced: `%1%'") % i->second.path);
slice.elems.push_back(i->second);
}
}
FState nf = unparseSlice(slice);
debug(printTerm(nf));
storeSuccessor(id, nf);
return slice;
}
static void checkSlice(const Slice & slice)
{
if (slice.elems.size() == 0)
throw Error("empty slice");
FSIdSet decl;
for (SliceElems::const_iterator i = slice.elems.begin();
i != slice.elems.end(); i++)
{
debug((string) i->id);
decl.insert(i->id);
}
for (FSIds::const_iterator i = slice.roots.begin();
i != slice.roots.end(); i++)
if (decl.find(*i) == decl.end())
throw Error(format("undefined id: %1%") % (string) *i);
for (SliceElems::const_iterator i = slice.elems.begin();
i != slice.elems.end(); i++)
for (FSIds::const_iterator j = i->refs.begin();
j != i->refs.end(); j++)
if (decl.find(*j) == decl.end())
throw Error(format("undefined id: %1%") % (string) *j);
}
void realiseSlice(const Slice & slice)
{
debug(format("realising slice"));
Nest nest(true);
checkSlice(slice);
/* Perhaps all paths already contain the right id? */
bool missing = false;
for (SliceElems::const_iterator i = slice.elems.begin();
i != slice.elems.end(); i++)
{
SliceElem elem = *i;
string id;
if (!queryDB(nixDB, dbPath2Id, elem.path, id)) {
if (pathExists(elem.path))
throw Error(format("path `%1%' obstructed") % elem.path);
missing = true;
break;
}
if (parseHash(id) != elem.id)
throw Error(format("path `%1%' obstructed") % elem.path);
}
if (!missing) {
debug(format("already installed"));
return;
}
/* For each element, expand its id at its path. */
for (SliceElems::const_iterator i = slice.elems.begin();
i != slice.elems.end(); i++)
{
SliceElem elem = *i;
expandId(elem.id, elem.path);
}
}