LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-09-20 17:58:18 +03:00
Code Issues Packages Projects Releases Wiki Activity

LibCore: Implement readlink() and current_executable_path() on GNU/Hurd

Browse Source 
Without using PATH_MAX :^)

To read a symlink, we can just open its file with O_NOLINK and read its
contents. To get the executable path, we could read the /proc/self/exe
link like the Linux version does; but that relies on procfs being
mounted. Instead, we could do what procfs itself does to get the path:
ask the proc server about it.
This commit is contained in:
Sergey Bugaev 2023-09-03 22:41:16 +03:00 committed by Andrew Kaster
parent cee38cf1e5
commit 29da1d7c23
Notes: sideshowbarker 2024-07-17 09:37:30 +09:00 
Author: https://github.com/bugaevc
Commit: https://github.com/SerenityOS/serenity/commit/29da1d7c23
Pull-request: https://github.com/SerenityOS/serenity/pull/20961
Reviewed-by: https://github.com/ADKaster ✅
1 changed files with 29 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
Userland/Libraries/LibCore/System.cpp
View File

@ -54,6 +54,13 @@ extern char** environ;
# include <sys/sysctl.h> # include <sys/sysctl.h>
#endif #endif
#if defined(AK_OS_GNU_HURD)
extern "C" {
# include <hurd.h>
}
# include <LibCore/File.h>
#endif
#define HANDLE_SYSCALL_RETURN_VALUE(syscall_name, rc, success_value) \ #define HANDLE_SYSCALL_RETURN_VALUE(syscall_name, rc, success_value) \
if ((rc) < 0) { \ if ((rc) < 0) { \
return Error::from_syscall(syscall_name##sv, rc); \ return Error::from_syscall(syscall_name##sv, rc); \
@ -1659,8 +1666,8 @@ ErrorOr<void> access(StringView pathname, int mode, int flags)
ErrorOr<DeprecatedString> readlink(StringView pathname) ErrorOr<DeprecatedString> readlink(StringView pathname)
{ {
// FIXME: Try again with a larger buffer. // FIXME: Try again with a larger buffer.
char data[PATH_MAX];
#ifdef AK_OS_SERENITY #ifdef AK_OS_SERENITY
char data[PATH_MAX];
Syscall::SC_readlink_params small_params { Syscall::SC_readlink_params small_params {
.path = { pathname.characters_without_null_termination(), pathname.length() }, .path = { pathname.characters_without_null_termination(), pathname.length() },
.buffer = { data, sizeof(data) }, .buffer = { data, sizeof(data) },
@ -1668,7 +1675,16 @@ ErrorOr<DeprecatedString> readlink(StringView pathname)
}; };
int rc = syscall(SC_readlink, &small_params); int rc = syscall(SC_readlink, &small_params);
HANDLE_SYSCALL_RETURN_VALUE("readlink", rc, DeprecatedString(data, rc)); HANDLE_SYSCALL_RETURN_VALUE("readlink", rc, DeprecatedString(data, rc));
#elif defined(AK_OS_GNU_HURD)
// PATH_MAX is not defined, nor is there an upper limit on path lengths.
// Let's do this the right way.
int fd = TRY(open(pathname, O_READ | O_NOLINK));
auto file = TRY(File::adopt_fd(fd, File::OpenMode::Read));
auto buffer = TRY(file->read_until_eof());
// TODO: Get rid of this copy here.
return DeprecatedString::copy(buffer);
#else #else
char data[PATH_MAX];
DeprecatedString path_string = pathname; DeprecatedString path_string = pathname;
int rc = ::readlink(path_string.characters(), data, sizeof(data)); int rc = ::readlink(path_string.characters(), data, sizeof(data));
if (rc == -1) if (rc == -1)
@ -1748,6 +1764,18 @@ ErrorOr<String> current_executable_path()
// Ignore error if it wasn't a symlink // Ignore error if it wasn't a symlink
if (ret == -1 && errno != EINVAL) if (ret == -1 && errno != EINVAL)
return Error::from_syscall("readlink"sv, -errno); return Error::from_syscall("readlink"sv, -errno);
#elif defined(AK_OS_GNU_HURD)
// We could read /proc/self/exe, but why rely on procfs being mounted
// if we can do the same thing procfs does and ask the proc server directly?
process_t proc = getproc();
if (!MACH_PORT_VALID(proc))
return Error::from_syscall("getproc"sv, -errno);
kern_return_t err = proc_get_exe(proc, getpid(), path);
mach_port_deallocate(mach_task_self(), proc);
if (err) {
__hurd_fail(static_cast<error_t>(err));
return Error::from_syscall("proc_get_exe"sv, -errno);
}
#elif defined(AK_OS_DRAGONFLY) #elif defined(AK_OS_DRAGONFLY)
return String::from_deprecated_string(TRY(readlink("/proc/curproc/file"sv))); return String::from_deprecated_string(TRY(readlink("/proc/curproc/file"sv)));
#elif defined(AK_OS_SOLARIS) #elif defined(AK_OS_SOLARIS)