Reduce max shared memory object name length#68541

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Merged
adamsitnik merged 2 commits into from
May 17, 2022
Merged

Reduce max shared memory object name length #68541

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3d0dc17
reduce max shared memory object name to 30
adamsitnik Apr 26, 2022
bcd6af6
use the fallback to be 100% safe
adamsitnik Apr 26, 2022
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29 changes: 23 additions & 6 deletions ...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
// the result of native shm_open does not work well with our subsequent call to mmap.
return null;
}
else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
{
Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
// in theory it should not happen anymore, but just to be extra safe we use the fallback
return null;
}
else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
{
throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

static string GenerateMapName()
{
const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
// The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
// macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
// The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
// It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
// but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
// According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
// Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
const int MaxNameLength = 30;
// The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
const string NamePrefix = "/dotnet_";
return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.
{
Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
"/dotnet_".CopyTo(span);
Span<char> guid = stackalloc char[32];
Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
Debug.Assert(charsWritten == 32);
NamePrefix.CopyTo(span);
guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.
});
}
}
Expand Down
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Reduce max shared memory object name length#68541

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 Merged

adamsitnik
merged 2 commits into

from

May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
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2 commits


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3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Reduce max shared memory object name length#68541

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 Merged

adamsitnik
merged 2 commits into

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May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
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3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Reduce max shared memory object name length#68541

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 Merged

adamsitnik
merged 2 commits into

from

May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
 Changes from all commits
Commits

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2 commits


Select commit
Hold shift + click to select a range
3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
Reduce max shared memory object name length#68541

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 Merged

adamsitnik
merged 2 commits into

from

May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Reduce max shared memory object name length#68541

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 Merged

adamsitnik
merged 2 commits into

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May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
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3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Reduce max shared memory object name length#68541

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 Merged

adamsitnik
merged 2 commits into

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May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
 Changes from all commits
Commits

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2 commits


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Hold shift + click to select a range
3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

Skip to content
Reduce max shared memory object name length#68541

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Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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 Merged

adamsitnik
merged 2 commits into

from

May 17, 2022
 Merged


Reduce max shared memory object name length
#68541
 Changes from all commits
Commits

Show all changes


2 commits


Select commit
Hold shift + click to select a range
3d0dc17

reduce max shared memory object name to 30


adamsitnik Apr 26, 2022
bcd6af6

use the fallback to be 100% safe


adamsitnik Apr 26, 2022

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Filter by extension
Conversations

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29 changes: 23 additions & 6 deletions
...ries/System.IO.MemoryMappedFiles/src/System/IO/MemoryMappedFiles/MemoryMappedFile.Unix.cs

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.

using System.Diagnostics;
using System.Text;
using Microsoft.Win32.SafeHandles;

namespace System.IO.MemoryMappedFiles
Expand DownExpand Up@@ -201,6 +202,12 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped
 // the result of native shm_open does not work well with our subsequent call to mmap.
 return null;
 }
 else if (errorInfo.Error == Interop.Error.ENAMETOOLONG)
 {
 Debug.Fail($"shm_open failed with ENAMETOOLONG for {Encoding.UTF8.GetByteCount(mapName)} byte long name.");
 // in theory it should not happen anymore, but just to be extra safe we use the fallback
 return null;
 }
 else if (errorInfo.Error != Interop.Error.EEXIST) // map with same name already existed
 {
 throw Interop.GetExceptionForIoErrno(errorInfo);
Expand DownExpand Up@@ -238,13 +245,23 @@ private static SafeFileHandle CreateSharedBackingObject(Interop.Sys.MemoryMapped

 static string GenerateMapName()
 {
 const int MaxSharedMemoryObjectNameLength = 32; // SHM_NAME_MAX on OSX ARM64, on other systems it's equal PATH_MAX (250)
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (32) and unique.
 return string.Create(MaxSharedMemoryObjectNameLength, 0, (span, state) =>
 // macOS shm_open documentation says that the sys-call can fail with ENAMETOOLONG if the name exceeds SHM_NAME_MAX characters.
 // The problem is that SHM_NAME_MAX is not defined anywhere and is not consistent amongst macOS versions (arm64 vs x64 for example).
 // It was reported in 2008 (https://lists.apple.com/archives/xcode-users/2008/Apr/msg00523.html),
 // but considered to be by design (http://web.archive.org/web/20140109200632/http://lists.apple.com/archives/darwin-development/2003/Mar/msg00244.html).
 // According to https://github.com/qt/qtbase/blob/1ed449e168af133184633d174fd7339a13d1d595/src/corelib/kernel/qsharedmemory.cpp#L53-L56 the actual value is 30.
 // Some other OSS libs use 32 (we did as well, but it was not enough) or 31, but we prefer 30 just to be extra safe.
 const int MaxNameLength = 30;
 // The POSIX shared memory object name must begin with '/'. After that we just want something short (30) and unique.
 const string NamePrefix = "/dotnet_";
 return string.Create(MaxNameLength, 0, (span, state) =>
Comment thread
adamsitnik marked this conversation as resolved.

 {
 Guid.NewGuid().TryFormat(span, out int charsWritten, "N");
 Debug.Assert(charsWritten == MaxSharedMemoryObjectNameLength);
 "/dotnet_".CopyTo(span);
 Span<char> guid = stackalloc char[32];
 Guid.NewGuid().TryFormat(guid, out int charsWritten, "N");
 Debug.Assert(charsWritten == 32);
 NamePrefix.CopyTo(span);
 guid.Slice(0, MaxNameLength - NamePrefix.Length).CopyTo(span.Slice(NamePrefix.Length));
 Debug.Assert(Encoding.UTF8.GetByteCount(span) <= MaxNameLength); // the standard uses Utf8
Comment thread
stephentoub marked this conversation as resolved.

 });
 }
 }
Expand Down