ObjFW  Check-in [c615b62ed8]

Overview
Comment:Don't use readdir_r

readdir_r can easily lead to stack overflows if the path is longer than
the space reserved for d_name in dirent. While some OSes use a length of
MAXNAMLEN + 1, others use just 1. This could be worked around by always
allocating a buffer of sizeof(struct dirent) + MAXNAMLEN (which would
work only in case MAXNAMLEN is actually the longest readdir_r can
return), but is probably not worth the risk, especially as glibc has
entirely deprecated readdir_r and it is expected to be removed from
POSIX.

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SHA3-256: c615b62ed8dfcdb37ded7c7a8b2c63d17f71c4f3f4f44850b08394fbd6e645d0
User & Date: js on 2024-04-16 23:50:40
Other Links: manifest | tags
Context
2024-04-17
20:45
forwarding: Don't grow the stack twice on ARM64 check-in: 8e95cb1c77 user: js tags: trunk
2024-04-16
23:50
Don't use readdir_r check-in: c615b62ed8 user: js tags: trunk
23:18
lookup-asm-arm64-elf.S: Save one instruction check-in: 460b84b9b2 user: js tags: trunk
Changes
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Modified configure.ac from [fa7714f07b] to [63f2b5a434].

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	AC_CHECK_FUNC(symlink, [
		AC_DEFINE(OF_HAVE_SYMLINK, 1, [Whether we have symlink()])
	])
	AC_CHECK_FUNCS([lstat])
	AC_CHECK_MEMBERS([struct stat.st_birthtime], [], [], [
		#include <sys/stat.h>
	])

	old_OBJCFLAGS="$OBJCFLAGS"
	OBJCFLAGS="$OBJCFLAGS -Werror"
	AC_MSG_CHECKING(for readdir_r)
	AC_COMPILE_IFELSE([
		AC_LANG_PROGRAM([
			#include <dirent.h>
		], [
			DIR *dir = 0;
			struct dirent entry, *result;

			readdir_r(dir, &entry, &result);
		])
	], [
		AC_MSG_RESULT(yes)
		AC_DEFINE(HAVE_READDIR_R, 1, [Whether we have readdir_r()])
	], [
		AC_MSG_RESULT(no)
	])
	OBJCFLAGS="$old_OBJCFLAGS"
])

AC_CHECK_HEADERS(dirent.h)
AC_CHECK_FUNCS([sysconf gmtime_r localtime_r])

case "$host_os" in
amigaos* | morphos*)








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	AC_CHECK_FUNC(symlink, [
		AC_DEFINE(OF_HAVE_SYMLINK, 1, [Whether we have symlink()])
	])
	AC_CHECK_FUNCS([lstat])
	AC_CHECK_MEMBERS([struct stat.st_birthtime], [], [], [
		#include <sys/stat.h>
	])




















])

AC_CHECK_HEADERS(dirent.h)
AC_CHECK_FUNCS([sysconf gmtime_r localtime_r])

case "$host_os" in
amigaos* | morphos*)
︙︙

Modified src/OFFileIRIHandler.m from [ef59c89349] to [d9639e50f4].

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static void
releasePasswdMutex(void)
{
	[passwdMutex release];
}
#endif
#if !defined(HAVE_READDIR_R) && defined(OF_HAVE_THREADS) && !defined(OF_WINDOWS)
static OFMutex *readdirMutex;

static void
releaseReaddirMutex(void)
{
	[readdirMutex release];
}








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static void
releasePasswdMutex(void)
{
	[passwdMutex release];
}
#endif
#if defined(OF_HAVE_THREADS) && !defined(__GLIBC__) && !defined(OF_WINDOWS)
static OFMutex *readdirMutex;

static void
releaseReaddirMutex(void)
{
	[readdirMutex release];
}
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	if (self != [OFFileIRIHandler class])
		return;

#if defined(OF_FILE_MANAGER_SUPPORTS_OWNER) && defined(OF_HAVE_THREADS)
	passwdMutex = [[OFMutex alloc] init];
	atexit(releasePasswdMutex);
#endif
#if !defined(HAVE_READDIR_R) && !defined(OF_WINDOWS) && defined(OF_HAVE_THREADS)
	readdirMutex = [[OFMutex alloc] init];
	atexit(releaseReaddirMutex);
#endif

#ifdef OF_WINDOWS
	if ((module = GetModuleHandle("msvcrt.dll")) != NULL)
		_wutime64FuncPtr = (int (*)(const wchar_t *,








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	if (self != [OFFileIRIHandler class])
		return;

#if defined(OF_FILE_MANAGER_SUPPORTS_OWNER) && defined(OF_HAVE_THREADS)
	passwdMutex = [[OFMutex alloc] init];
	atexit(releasePasswdMutex);
#endif
#if defined(OF_HAVE_THREADS) && !defined(__GLIBC__) && !defined(OF_WINDOWS)
	readdirMutex = [[OFMutex alloc] init];
	atexit(releaseReaddirMutex);
#endif

#ifdef OF_WINDOWS
	if ((module = GetModuleHandle("msvcrt.dll")) != NULL)
		_wutime64FuncPtr = (int (*)(const wchar_t *,
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	OFStringEncoding encoding = [OFLocale encoding];
	DIR *dir;
	if ((dir = opendir([path cStringWithEncoding: encoding])) == NULL)
		@throw [OFOpenItemFailedException exceptionWithIRI: IRI
							      mode: nil
							     errNo: errno];

# if !defined(HAVE_READDIR_R) && defined(OF_HAVE_THREADS)
	@try {
		[readdirMutex lock];
	} @catch (id e) {
		closedir(dir);
		@throw e;
	}
# endif

	@try {
		for (;;) {
			struct dirent *dirent;
# ifdef HAVE_READDIR_R
			struct dirent buffer;
# endif
			OFString *file;

# ifdef HAVE_READDIR_R
			if (readdir_r(dir, &buffer, &dirent) != 0)
				@throw [OFReadFailedException
				    exceptionWithObject: self
					requestedLength: 0
						  errNo: errno];

			if (dirent == NULL)
				break;
# else
			errno = 0;
			if ((dirent = readdir(dir)) == NULL) {
				if (errno == 0)
					break;
				else
					@throw [OFReadFailedException
					    exceptionWithObject: self
						requestedLength: 0
							  errNo: errno];
			}
# endif

			if (strcmp(dirent->d_name, ".") == 0 ||
			    strcmp(dirent->d_name, "..") == 0)
				continue;

			file = [[OFString alloc] initWithCString: dirent->d_name
							encoding: encoding];
			@try {
				[IRIs addObject:
				    [IRI IRIByAppendingPathComponent: file]];
			} @finally {
				[file release];
			}
		}
	} @finally {
		closedir(dir);
# if !defined(HAVE_READDIR_R) && defined(OF_HAVE_THREADS)
		[readdirMutex unlock];
# endif
	}
#endif

	[IRIs makeImmutable];









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	OFStringEncoding encoding = [OFLocale encoding];
	DIR *dir;
	if ((dir = opendir([path cStringWithEncoding: encoding])) == NULL)
		@throw [OFOpenItemFailedException exceptionWithIRI: IRI
							      mode: nil
							     errNo: errno];

# if defined(OF_HAVE_THREADS) && !defined(__GLIBC__)
	@try {
		[readdirMutex lock];
	} @catch (id e) {
		closedir(dir);
		@throw e;
	}
# endif

	@try {
		for (;;) {
			struct dirent *dirent;



			OFString *file;











			errno = 0;
			if ((dirent = readdir(dir)) == NULL) {
				if (errno == 0)
					break;
				else
					@throw [OFReadFailedException
					    exceptionWithObject: self
						requestedLength: 0
							  errNo: errno];
			}


			if (strcmp(dirent->d_name, ".") == 0 ||
			    strcmp(dirent->d_name, "..") == 0)
				continue;

			file = [[OFString alloc] initWithCString: dirent->d_name
							encoding: encoding];
			@try {
				[IRIs addObject:
				    [IRI IRIByAppendingPathComponent: file]];
			} @finally {
				[file release];
			}
		}
	} @finally {
		closedir(dir);
# if defined(OF_HAVE_THREADS) && !defined(__GLIBC__)
		[readdirMutex unlock];
# endif
	}
#endif

	[IRIs makeImmutable];
︙︙

Fossil 2.23 [47362306a7] 2023-11-01 18:56:47
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