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* Don't use fork() in copyPath(), but a string buffer.

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This commit is contained in:
Eelco Dolstra 2005-03-03 13:58:02 +00:00
parent 9e6bca8765
commit 4bbdcfbb45
2 changed files with 17 additions and 47 deletions
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61
src/libstore/store.cc
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@ -1,7 +1,6 @@
#include <iostream>
#include <algorithm>
#include <sys/wait.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
@ -126,20 +125,24 @@ void createStoreTransaction(Transaction & txn)
struct CopySink : DumpSink
{
int fd;
string s;
virtual void operator () (const unsigned char * data, unsigned int len)
{
writeFull(fd, data, len);
s.append((const char *) data, len);
}
};
struct CopySource : RestoreSource
{
int fd;
string & s;
unsigned int pos;
CopySource(string & _s) : s(_s), pos(0) { }
virtual void operator () (unsigned char * data, unsigned int len)
{
readFull(fd, data, len);
s.copy((char *) data, len, pos);
pos += len;
assert(pos <= s.size());
}
};
@ -148,52 +151,19 @@ void copyPath(const Path & src, const Path & dst)
{
debug(format("copying `%1%' to `%2%'") % src % dst);
/* Unfortunately C++ doesn't support coprocedures, so we have no
nice way to chain CopySink and CopySource together. Instead we
fork off a child to run the sink. (Fork-less platforms should
use a thread). */
/* Dump an archive of the path `src' into a string buffer, then
restore the archive to `dst'. This is not a very good method
for very large paths, but `copyPath' is mainly used for small
files. */
/* Create a pipe. */
Pipe pipe;
pipe.create();
/* Fork. */
Pid pid;
pid = fork();
switch (pid) {
case -1:
throw SysError("unable to fork");
case 0: /* child */
try {
pipe.writeSide.close();
CopySource source;
source.fd = pipe.readSide;
restorePath(dst, source);
_exit(0);
} catch (exception & e) {
cerr << "error: " << e.what() << endl;
}
_exit(1);
}
/* Parent. */
pipe.readSide.close();
CopySink sink;
sink.fd = pipe.writeSide;
{
SwitchToOriginalUser sw;
dumpPath(src, sink);
}
/* Wait for the child to finish. */
int status = pid.wait(true);
if (!statusOk(status))
throw Error(format("cannot copy `%1% to `%2%': child %3%")
% src % dst % statusToString(status));
CopySource source(sink.s);
restorePath(dst, source);
}
@ -619,9 +589,6 @@ Path addToStore(const Path & _srcPath)
if (pathExists(dstPath)) deletePath(dstPath);
/* !!! race: srcPath might change between hashPath() and
here! */
copyPath(srcPath, dstPath);
Hash h2 = hashPath(htSHA256, dstPath);