mirror of
https://github.com/privatevoid-net/nix-super.git
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45 lines
1.1 KiB
C++
45 lines
1.1 KiB
C++
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#include <sys/time.h>
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#include "util.hh"
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#include "types.hh"
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namespace nix {
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void createSymlink(const Path & target, const Path & link,
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std::optional<time_t> mtime)
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{
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if (symlink(target.c_str(), link.c_str()))
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throw SysError("creating symlink from '%1%' to '%2%'", link, target);
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if (mtime) {
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struct timeval times[2];
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times[0].tv_sec = *mtime;
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times[0].tv_usec = 0;
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times[1].tv_sec = *mtime;
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times[1].tv_usec = 0;
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if (lutimes(link.c_str(), times))
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throw SysError("setting time of symlink '%s'", link);
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}
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}
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void replaceSymlink(const Path & target, const Path & link,
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std::optional<time_t> mtime)
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{
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for (unsigned int n = 0; true; n++) {
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Path tmp = canonPath(fmt("%s/.%d_%s", dirOf(link), n, baseNameOf(link)));
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try {
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createSymlink(target, tmp, mtime);
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} catch (SysError & e) {
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if (e.errNo == EEXIST) continue;
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throw;
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}
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if (rename(tmp.c_str(), link.c_str()) != 0)
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throw SysError("renaming '%1%' to '%2%'", tmp, link);
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break;
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}
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}
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}
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