wrapper.c - jrn/git - Git at Google

 /*
  * Various trivial helper wrappers around standard functions
  */
 #include "cache.h"

 static void do_nothing(size_t size)
 {
 }

 static void (*try_to_free_routine)(size_t size) = do_nothing;

 static void memory_limit_check(size_t size)
 {
 	static int limit = -1;
 	if (limit == -1) {
 		const char *env = getenv("GIT_ALLOC_LIMIT");
 		limit = env ? atoi(env) * 1024 : 0;
 	}
 	if (limit && size > limit)
 		die("attempting to allocate %"PRIuMAX" over limit %d",
 		    (intmax_t)size, limit);
 }

 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
 {
 	try_to_free_t old = try_to_free_routine;
 	if (!routine)
 		routine = do_nothing;
 	try_to_free_routine = routine;
 	return old;
 }

 char *xstrdup(const char *str)
 {
 	char *ret = strdup(str);
 	if (!ret) {
 		try_to_free_routine(strlen(str) + 1);
 		ret = strdup(str);
 		if (!ret)
 			die("Out of memory, strdup failed");
 	}
 	return ret;
 }

 void *xmalloc(size_t size)
 {
 	void *ret;

 	memory_limit_check(size);
 	ret = malloc(size);
 	if (!ret && !size)
 		ret = malloc(1);
 	if (!ret) {
 		try_to_free_routine(size);
 		ret = malloc(size);
 		if (!ret && !size)
 			ret = malloc(1);
 		if (!ret)
 			die("Out of memory, malloc failed (tried to allocate %lu bytes)",
 			    (unsigned long)size);
 	}
 #ifdef XMALLOC_POISON
 	memset(ret, 0xA5, size);
 #endif
 	return ret;
 }

 void *xmallocz(size_t size)
 {
 	void *ret;
 	if (unsigned_add_overflows(size, 1))
 		die("Data too large to fit into virtual memory space.");
 	ret = xmalloc(size + 1);
 	((char*)ret)[size] = 0;
 	return ret;
 }

 /*
  * xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
  * "data" to the allocated memory, zero terminates the allocated memory,
  * and returns a pointer to the allocated memory. If the allocation fails,
  * the program dies.
  */
 void *xmemdupz(const void *data, size_t len)
 {
 	return memcpy(xmallocz(len), data, len);
 }

 char *xstrndup(const char *str, size_t len)
 {
 	char *p = memchr(str, '\0', len);
 	return xmemdupz(str, p ? p - str : len);
 }

 void *xrealloc(void *ptr, size_t size)
 {
 	void *ret;

 	memory_limit_check(size);
 	ret = realloc(ptr, size);
 	if (!ret && !size)
 		ret = realloc(ptr, 1);
 	if (!ret) {
 		try_to_free_routine(size);
 		ret = realloc(ptr, size);
 		if (!ret && !size)
 			ret = realloc(ptr, 1);
 		if (!ret)
 			die("Out of memory, realloc failed");
 	}
 	return ret;
 }

 void *xcalloc(size_t nmemb, size_t size)
 {
 	void *ret;

 	memory_limit_check(size * nmemb);
 	ret = calloc(nmemb, size);
 	if (!ret && (!nmemb || !size))
 		ret = calloc(1, 1);
 	if (!ret) {
 		try_to_free_routine(nmemb * size);
 		ret = calloc(nmemb, size);
 		if (!ret && (!nmemb || !size))
 			ret = calloc(1, 1);
 		if (!ret)
 			die("Out of memory, calloc failed");
 	}
 	return ret;
 }

 /*
  * xread() is the same a read(), but it automatically restarts read()
  * operations with a recoverable error (EAGAIN and EINTR). xread()
  * DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
  */
 ssize_t xread(int fd, void *buf, size_t len)
 {
 	ssize_t nr;
 	while (1) {
 		nr = read(fd, buf, len);
 		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 			continue;
 		return nr;
 	}
 }

 /*
  * xwrite() is the same a write(), but it automatically restarts write()
  * operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
  * GUARANTEE that "len" bytes is written even if the operation is successful.
  */
 ssize_t xwrite(int fd, const void *buf, size_t len)
 {
 	ssize_t nr;
 	while (1) {
 		nr = write(fd, buf, len);
 		if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
 			continue;
 		return nr;
 	}
 }

 ssize_t read_in_full(int fd, void *buf, size_t count)
 {
 	char *p = buf;
 	ssize_t total = 0;

 	while (count > 0) {
 		ssize_t loaded = xread(fd, p, count);
 		if (loaded < 0)
 			return -1;
 		if (loaded == 0)
 			return total;
 		count -= loaded;
 		p += loaded;
 		total += loaded;
 	}

 	return total;
 }

 ssize_t write_in_full(int fd, const void *buf, size_t count)
 {
 	const char *p = buf;
 	ssize_t total = 0;

 	while (count > 0) {
 		ssize_t written = xwrite(fd, p, count);
 		if (written < 0)
 			return -1;
 		if (!written) {
 			errno = ENOSPC;
 			return -1;
 		}
 		count -= written;
 		p += written;
 		total += written;
 	}

 	return total;
 }

 int xdup(int fd)
 {
 	int ret = dup(fd);
 	if (ret < 0)
 		die_errno("dup failed");
 	return ret;
 }

 FILE *xfdopen(int fd, const char *mode)
 {
 	FILE *stream = fdopen(fd, mode);
 	if (stream == NULL)
 		die_errno("Out of memory? fdopen failed");
 	return stream;
 }

 int xmkstemp(char *template)
 {
 	int fd;
 	char origtemplate[PATH_MAX];
 	strlcpy(origtemplate, template, sizeof(origtemplate));

 	fd = mkstemp(template);
 	if (fd < 0) {
 		int saved_errno = errno;
 		const char *nonrelative_template;

 		if (strlen(template) != strlen(origtemplate))
 			template = origtemplate;

 		nonrelative_template = absolute_path(template);
 		errno = saved_errno;
 		die_errno("Unable to create temporary file '%s'",
 			nonrelative_template);
 	}
 	return fd;
 }

 /* git_mkstemp() - create tmp file honoring TMPDIR variable */
 int git_mkstemp(char *path, size_t len, const char *template)
 {
 	const char *tmp;
 	size_t n;

 	tmp = getenv("TMPDIR");
 	if (!tmp)
 		tmp = "/tmp";
 	n = snprintf(path, len, "%s/%s", tmp, template);
 	if (len <= n) {
 		errno = ENAMETOOLONG;
 		return -1;
 	}
 	return mkstemp(path);
 }

 /* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
 int git_mkstemps(char *path, size_t len, const char *template, int suffix_len)
 {
 	const char *tmp;
 	size_t n;

 	tmp = getenv("TMPDIR");
 	if (!tmp)
 		tmp = "/tmp";
 	n = snprintf(path, len, "%s/%s", tmp, template);
 	if (len <= n) {
 		errno = ENAMETOOLONG;
 		return -1;
 	}
 	return mkstemps(path, suffix_len);
 }

 /* Adapted from libiberty's mkstemp.c. */

 #undef TMP_MAX
 #define TMP_MAX 16384

 int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
 {
 	static const char letters[] =
 		"abcdefghijklmnopqrstuvwxyz"
 		"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 		"0123456789";
 	static const int num_letters = 62;
 	uint64_t value;
 	struct timeval tv;
 	char *template;
 	size_t len;
 	int fd, count;

 	len = strlen(pattern);

 	if (len < 6 + suffix_len) {
 		errno = EINVAL;
 		return -1;
 	}

 	if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
 		errno = EINVAL;
 		return -1;
 	}

 	/*
 	 * Replace pattern's XXXXXX characters with randomness.
 	 * Try TMP_MAX different filenames.
 	 */
 	gettimeofday(&tv, NULL);
 	value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
 	template = &pattern[len - 6 - suffix_len];
 	for (count = 0; count < TMP_MAX; ++count) {
 		uint64_t v = value;
 		/* Fill in the random bits. */
 		template[0] = letters[v % num_letters]; v /= num_letters;
 		template[1] = letters[v % num_letters]; v /= num_letters;
 		template[2] = letters[v % num_letters]; v /= num_letters;
 		template[3] = letters[v % num_letters]; v /= num_letters;
 		template[4] = letters[v % num_letters]; v /= num_letters;
 		template[5] = letters[v % num_letters]; v /= num_letters;

 		fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
 		if (fd >= 0)
 			return fd;
 		/*
 		 * Fatal error (EPERM, ENOSPC etc).
 		 * It doesn't make sense to loop.
 		 */
 		if (errno != EEXIST)
 			break;
 		/*
 		 * This is a random value.  It is only necessary that
 		 * the next TMP_MAX values generated by adding 7777 to
 		 * VALUE are different with (module 2^32).
 		 */
 		value += 7777;
 	}
 	/* We return the null string if we can't find a unique file name.  */
 	pattern[0] = '\0';
 	return -1;
 }

 int git_mkstemp_mode(char *pattern, int mode)
 {
 	/* mkstemp is just mkstemps with no suffix */
 	return git_mkstemps_mode(pattern, 0, mode);
 }

 int gitmkstemps(char *pattern, int suffix_len)
 {
 	return git_mkstemps_mode(pattern, suffix_len, 0600);
 }

 int xmkstemp_mode(char *template, int mode)
 {
 	int fd;
 	char origtemplate[PATH_MAX];
 	strlcpy(origtemplate, template, sizeof(origtemplate));

 	fd = git_mkstemp_mode(template, mode);
 	if (fd < 0) {
 		int saved_errno = errno;
 		const char *nonrelative_template;

 		if (!template[0])
 			template = origtemplate;

 		nonrelative_template = absolute_path(template);
 		errno = saved_errno;
 		die_errno("Unable to create temporary file '%s'",
 			nonrelative_template);
 	}
 	return fd;
 }

 static int warn_if_unremovable(const char *op, const char *file, int rc)
 {
 	if (rc < 0) {
 		int err = errno;
 		if (ENOENT != err) {
 			warning("unable to %s %s: %s",
 				op, file, strerror(errno));
 			errno = err;
 		}
 	}
 	return rc;
 }

 int unlink_or_warn(const char *file)
 {
 	return warn_if_unremovable("unlink", file, unlink(file));
 }

 int rmdir_or_warn(const char *file)
 {
 	return warn_if_unremovable("rmdir", file, rmdir(file));
 }

 int remove_or_warn(unsigned int mode, const char *file)
 {
 	return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
 }

 void warn_on_inaccessible(const char *path)
 {
 	warning(_("unable to access '%s': %s"), path, strerror(errno));
 }

 static int access_error_is_ok(int err, unsigned flag)
 {
 	return err == ENOENT || err == ENOTDIR ||
 		((flag & ACCESS_EACCES_OK) && err == EACCES);
 }

 int access_or_warn(const char *path, int mode, unsigned flag)
 {
 	int ret = access(path, mode);
 	if (ret && !access_error_is_ok(errno, flag))
 		warn_on_inaccessible(path);
 	return ret;
 }

 int access_or_die(const char *path, int mode, unsigned flag)
 {
 	int ret = access(path, mode);
 	if (ret && !access_error_is_ok(errno, flag))
 		die_errno(_("unable to access '%s'"), path);
 	return ret;
 }

 struct passwd *xgetpwuid_self(void)
 {
 	struct passwd *pw;

 	errno = 0;
 	pw = getpwuid(getuid());
 	if (!pw)
 		die(_("unable to look up current user in the passwd file: %s"),
 		    errno ? strerror(errno) : _("no such user"));
 	return pw;
 }
	/*
	* Various trivial helper wrappers around standard functions
	*/
	#include "cache.h"

	static void do_nothing(size_t size)
	{
	}

	static void (*try_to_free_routine)(size_t size) = do_nothing;

	static void memory_limit_check(size_t size)
	{
	static int limit = -1;
	if (limit == -1) {
	const char *env = getenv("GIT_ALLOC_LIMIT");
	limit = env ? atoi(env) * 1024 : 0;
	}
	if (limit && size > limit)
	die("attempting to allocate %"PRIuMAX" over limit %d",
	(intmax_t)size, limit);
	}

	try_to_free_t set_try_to_free_routine(try_to_free_t routine)
	{
	try_to_free_t old = try_to_free_routine;
	if (!routine)
	routine = do_nothing;
	try_to_free_routine = routine;
	return old;
	}

	char xstrdup(const char str)
	{
	char *ret = strdup(str);
	if (!ret) {
	try_to_free_routine(strlen(str) + 1);
	ret = strdup(str);
	if (!ret)
	die("Out of memory, strdup failed");
	}
	return ret;
	}

	void *xmalloc(size_t size)
	{
	void *ret;

	memory_limit_check(size);
	ret = malloc(size);
	if (!ret && !size)
	ret = malloc(1);
	if (!ret) {
	try_to_free_routine(size);
	ret = malloc(size);
	if (!ret && !size)
	ret = malloc(1);
	if (!ret)
	die("Out of memory, malloc failed (tried to allocate %lu bytes)",
	(unsigned long)size);
	}
	#ifdef XMALLOC_POISON
	memset(ret, 0xA5, size);
	#endif
	return ret;
	}

	void *xmallocz(size_t size)
	{
	void *ret;
	if (unsigned_add_overflows(size, 1))
	die("Data too large to fit into virtual memory space.");
	ret = xmalloc(size + 1);
	((char*)ret)[size] = 0;
	return ret;
	}

	/*
	* xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
	* "data" to the allocated memory, zero terminates the allocated memory,
	* and returns a pointer to the allocated memory. If the allocation fails,
	* the program dies.
	*/
	void xmemdupz(const void data, size_t len)
	{
	return memcpy(xmallocz(len), data, len);
	}

	char xstrndup(const char str, size_t len)
	{
	char *p = memchr(str, '\0', len);
	return xmemdupz(str, p ? p - str : len);
	}

	void xrealloc(void ptr, size_t size)
	{
	void *ret;

	memory_limit_check(size);
	ret = realloc(ptr, size);
	if (!ret && !size)
	ret = realloc(ptr, 1);
	if (!ret) {
	try_to_free_routine(size);
	ret = realloc(ptr, size);
	if (!ret && !size)
	ret = realloc(ptr, 1);
	if (!ret)
	die("Out of memory, realloc failed");
	}
	return ret;
	}

	void *xcalloc(size_t nmemb, size_t size)
	{
	void *ret;

	memory_limit_check(size * nmemb);
	ret = calloc(nmemb, size);
	if (!ret && (!nmemb \|\| !size))
	ret = calloc(1, 1);
	if (!ret) {
	try_to_free_routine(nmemb * size);
	ret = calloc(nmemb, size);
	if (!ret && (!nmemb \|\| !size))
	ret = calloc(1, 1);
	if (!ret)
	die("Out of memory, calloc failed");
	}
	return ret;
	}

	/*
	* xread() is the same a read(), but it automatically restarts read()
	* operations with a recoverable error (EAGAIN and EINTR). xread()
	* DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
	*/
	ssize_t xread(int fd, void *buf, size_t len)
	{
	ssize_t nr;
	while (1) {
	nr = read(fd, buf, len);
	if ((nr < 0) && (errno == EAGAIN \|\| errno == EINTR))
	continue;
	return nr;
	}
	}

	/*
	* xwrite() is the same a write(), but it automatically restarts write()
	* operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
	* GUARANTEE that "len" bytes is written even if the operation is successful.
	*/
	ssize_t xwrite(int fd, const void *buf, size_t len)
	{
	ssize_t nr;
	while (1) {
	nr = write(fd, buf, len);
	if ((nr < 0) && (errno == EAGAIN \|\| errno == EINTR))
	continue;
	return nr;
	}
	}

	ssize_t read_in_full(int fd, void *buf, size_t count)
	{
	char *p = buf;
	ssize_t total = 0;

	while (count > 0) {
	ssize_t loaded = xread(fd, p, count);
	if (loaded < 0)
	return -1;
	if (loaded == 0)
	return total;
	count -= loaded;
	p += loaded;
	total += loaded;
	}

	return total;
	}

	ssize_t write_in_full(int fd, const void *buf, size_t count)
	{
	const char *p = buf;
	ssize_t total = 0;

	while (count > 0) {
	ssize_t written = xwrite(fd, p, count);
	if (written < 0)
	return -1;
	if (!written) {
	errno = ENOSPC;
	return -1;
	}
	count -= written;
	p += written;
	total += written;
	}

	return total;
	}

	int xdup(int fd)
	{
	int ret = dup(fd);
	if (ret < 0)
	die_errno("dup failed");
	return ret;
	}

	FILE xfdopen(int fd, const char mode)
	{
	FILE *stream = fdopen(fd, mode);
	if (stream == NULL)
	die_errno("Out of memory? fdopen failed");
	return stream;
	}

	int xmkstemp(char *template)
	{
	int fd;
	char origtemplate[PATH_MAX];
	strlcpy(origtemplate, template, sizeof(origtemplate));

	fd = mkstemp(template);
	if (fd < 0) {
	int saved_errno = errno;
	const char *nonrelative_template;

	if (strlen(template) != strlen(origtemplate))
	template = origtemplate;

	nonrelative_template = absolute_path(template);
	errno = saved_errno;
	die_errno("Unable to create temporary file '%s'",
	nonrelative_template);
	}
	return fd;
	}

	/* git_mkstemp() - create tmp file honoring TMPDIR variable */
	int git_mkstemp(char path, size_t len, const char template)
	{
	const char *tmp;
	size_t n;

	tmp = getenv("TMPDIR");
	if (!tmp)
	tmp = "/tmp";
	n = snprintf(path, len, "%s/%s", tmp, template);
	if (len <= n) {
	errno = ENAMETOOLONG;
	return -1;
	}
	return mkstemp(path);
	}

	/* git_mkstemps() - create tmp file with suffix honoring TMPDIR variable. */
	int git_mkstemps(char path, size_t len, const char template, int suffix_len)
	{
	const char *tmp;
	size_t n;

	tmp = getenv("TMPDIR");
	if (!tmp)
	tmp = "/tmp";
	n = snprintf(path, len, "%s/%s", tmp, template);
	if (len <= n) {
	errno = ENAMETOOLONG;
	return -1;
	}
	return mkstemps(path, suffix_len);
	}

	/* Adapted from libiberty's mkstemp.c. */

	#undef TMP_MAX
	#define TMP_MAX 16384

	int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
	{
	static const char letters[] =
	"abcdefghijklmnopqrstuvwxyz"
	"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
	"0123456789";
	static const int num_letters = 62;
	uint64_t value;
	struct timeval tv;
	char *template;
	size_t len;
	int fd, count;

	len = strlen(pattern);

	if (len < 6 + suffix_len) {
	errno = EINVAL;
	return -1;
	}

	if (strncmp(&pattern[len - 6 - suffix_len], "XXXXXX", 6)) {
	errno = EINVAL;
	return -1;
	}

	/*
	* Replace pattern's XXXXXX characters with randomness.
	* Try TMP_MAX different filenames.
	*/
	gettimeofday(&tv, NULL);
	value = ((size_t)(tv.tv_usec << 16)) ^ tv.tv_sec ^ getpid();
	template = &pattern[len - 6 - suffix_len];
	for (count = 0; count < TMP_MAX; ++count) {
	uint64_t v = value;
	/* Fill in the random bits. */
	template[0] = letters[v % num_letters]; v /= num_letters;
	template[1] = letters[v % num_letters]; v /= num_letters;
	template[2] = letters[v % num_letters]; v /= num_letters;
	template[3] = letters[v % num_letters]; v /= num_letters;
	template[4] = letters[v % num_letters]; v /= num_letters;
	template[5] = letters[v % num_letters]; v /= num_letters;

	fd = open(pattern, O_CREAT \| O_EXCL \| O_RDWR, mode);
	if (fd >= 0)
	return fd;
	/*
	* Fatal error (EPERM, ENOSPC etc).
	* It doesn't make sense to loop.
	*/
	if (errno != EEXIST)
	break;
	/*
	* This is a random value. It is only necessary that
	* the next TMP_MAX values generated by adding 7777 to
	* VALUE are different with (module 2^32).
	*/
	value += 7777;
	}
	/* We return the null string if we can't find a unique file name. */
	pattern[0] = '\0';
	return -1;
	}

	int git_mkstemp_mode(char *pattern, int mode)
	{
	/* mkstemp is just mkstemps with no suffix */
	return git_mkstemps_mode(pattern, 0, mode);
	}

	int gitmkstemps(char *pattern, int suffix_len)
	{
	return git_mkstemps_mode(pattern, suffix_len, 0600);
	}

	int xmkstemp_mode(char *template, int mode)
	{
	int fd;
	char origtemplate[PATH_MAX];
	strlcpy(origtemplate, template, sizeof(origtemplate));

	fd = git_mkstemp_mode(template, mode);
	if (fd < 0) {
	int saved_errno = errno;
	const char *nonrelative_template;

	if (!template[0])
	template = origtemplate;

	nonrelative_template = absolute_path(template);
	errno = saved_errno;
	die_errno("Unable to create temporary file '%s'",
	nonrelative_template);
	}
	return fd;
	}

	static int warn_if_unremovable(const char op, const char file, int rc)
	{
	if (rc < 0) {
	int err = errno;
	if (ENOENT != err) {
	warning("unable to %s %s: %s",
	op, file, strerror(errno));
	errno = err;
	}
	}
	return rc;
	}

	int unlink_or_warn(const char *file)
	{
	return warn_if_unremovable("unlink", file, unlink(file));
	}

	int rmdir_or_warn(const char *file)
	{
	return warn_if_unremovable("rmdir", file, rmdir(file));
	}

	int remove_or_warn(unsigned int mode, const char *file)
	{
	return S_ISGITLINK(mode) ? rmdir_or_warn(file) : unlink_or_warn(file);
	}

	void warn_on_inaccessible(const char *path)
	{
	warning(_("unable to access '%s': %s"), path, strerror(errno));
	}

	static int access_error_is_ok(int err, unsigned flag)
	{
	return err == ENOENT \|\| err == ENOTDIR \|\|
	((flag & ACCESS_EACCES_OK) && err == EACCES);
	}

	int access_or_warn(const char *path, int mode, unsigned flag)
	{
	int ret = access(path, mode);
	if (ret && !access_error_is_ok(errno, flag))
	warn_on_inaccessible(path);
	return ret;
	}

	int access_or_die(const char *path, int mode, unsigned flag)
	{
	int ret = access(path, mode);
	if (ret && !access_error_is_ok(errno, flag))
	die_errno(_("unable to access '%s'"), path);
	return ret;
	}

	struct passwd *xgetpwuid_self(void)
	{
	struct passwd *pw;

	errno = 0;
	pw = getpwuid(getuid());
	if (!pw)
	die(_("unable to look up current user in the passwd file: %s"),
	errno ? strerror(errno) : _("no such user"));
	return pw;
	}