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Fix 1117: Use realpath in stage1 Darwin os_self_exe_path #1128

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Merged
merged 3 commits into from
Jun 18, 2018
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Fix 1117: Use realpath in stage1 Darwin os_self_exe_path #1128

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e6b6915
Fix 1117: Use realpath in stage1 Darwin os_self_exe_path
jbsolomon Jun 17, 2018
0456822
Fix 1117: Tweak realpath logic to use out_path as scratch space
jbsolomon Jun 18, 2018
c7057bd
Fix 1117: Revise realpath scratch logic
jbsolomon Jun 18, 2018
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21 changes: 19 additions & 2 deletions src/os.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -989,12 +989,29 @@ int os_self_exe_path(Buf *out_path) {
}

#elif defined(ZIG_OS_DARWIN)
// How long is the executable's path?
uint32_t u32_len = 0;
int ret1 = _NSGetExecutablePath(nullptr, &u32_len);
assert(ret1 != 0);
buf_resize(out_path, u32_len);
int ret2 = _NSGetExecutablePath(buf_ptr(out_path), &u32_len);

// Make a buffer having room for the temp path.
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@bnoordhuis bnoordhuis Jun 18, 2018 •
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This might just be me but I personally don't really like comments that just say what the code on the line below does.

As a rule of thumb, comments should explain what won't be obvious from just looking at the code, not restate the code in prose.

edit: hadn't noticed this has been merged between starting and finishing the review.

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@binary132 binary132 Jun 19, 2018

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The justification is that it makes code faster to read.

Buf *tmp = buf_alloc_fixed(u32_len);

// Fill the executable path.
int ret2 = _NSGetExecutablePath(buf_ptr(tmp), &u32_len);
assert(ret2 == 0);

// Resolve the real path from that.
buf_resize(out_path, PATH_MAX);
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@bnoordhuis bnoordhuis Jun 18, 2018

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Probably not relevant to Zig but in libuv we allocate 2*PATH_MAX to work around a bug in old versions of Apple's libc where the expanded path is sometimes > PATH_MAX.

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@andrewrk andrewrk Jun 18, 2018

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Thanks, I'll throw that in

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@andrewrk andrewrk Jun 18, 2018

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cd4676a

char *real_path = realpath(buf_ptr(tmp), buf_ptr(out_path));
assert(real_path == buf_ptr(out_path));

// Deallocate our scratch space.
buf_deinit(tmp);

// Resize out_path for the correct length.
buf_resize(out_path, strlen(buf_ptr(out_path)));

return 0;
#elif defined(ZIG_OS_LINUX)
buf_resize(out_path, 256);
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