mirror of
https://github.com/git/git
synced 2024-08-27 19:49:21 +00:00
![Pranit Bauva](/assets/img/avatar_default.png)
is_empty_file() can help to refactor a lot of code. This will be very helpful in porting "git bisect" to C. Suggested-by: Torsten Bögershausen <tboegi@web.de> Mentored-by: Lars Schneider <larsxschneider@gmail.com> Mentored-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Pranit Bauva <pranit.bauva@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
706 lines
15 KiB
C
706 lines
15 KiB
C
/*
|
|
* Various trivial helper wrappers around standard functions
|
|
*/
|
|
#include "cache.h"
|
|
#include "config.h"
|
|
|
|
static void do_nothing(size_t size)
|
|
{
|
|
}
|
|
|
|
static void (*try_to_free_routine)(size_t size) = do_nothing;
|
|
|
|
static int memory_limit_check(size_t size, int gentle)
|
|
{
|
|
static size_t limit = 0;
|
|
if (!limit) {
|
|
limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
|
|
if (!limit)
|
|
limit = SIZE_MAX;
|
|
}
|
|
if (size > limit) {
|
|
if (gentle) {
|
|
error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
|
|
(uintmax_t)size, (uintmax_t)limit);
|
|
return -1;
|
|
} else
|
|
die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
|
|
(uintmax_t)size, (uintmax_t)limit);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static void *do_xmalloc(size_t size, int gentle)
|
|
{
|
|
void *ret;
|
|
|
|
if (memory_limit_check(size, gentle))
|
|
return NULL;
|
|
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) {
|
|
if (!gentle)
|
|
die("Out of memory, malloc failed (tried to allocate %lu bytes)",
|
|
(unsigned long)size);
|
|
else {
|
|
error("Out of memory, malloc failed (tried to allocate %lu bytes)",
|
|
(unsigned long)size);
|
|
return NULL;
|
|
}
|
|
}
|
|
}
|
|
#ifdef XMALLOC_POISON
|
|
memset(ret, 0xA5, size);
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
void *xmalloc(size_t size)
|
|
{
|
|
return do_xmalloc(size, 0);
|
|
}
|
|
|
|
static void *do_xmallocz(size_t size, int gentle)
|
|
{
|
|
void *ret;
|
|
if (unsigned_add_overflows(size, 1)) {
|
|
if (gentle) {
|
|
error("Data too large to fit into virtual memory space.");
|
|
return NULL;
|
|
} else
|
|
die("Data too large to fit into virtual memory space.");
|
|
}
|
|
ret = do_xmalloc(size + 1, gentle);
|
|
if (ret)
|
|
((char*)ret)[size] = 0;
|
|
return ret;
|
|
}
|
|
|
|
void *xmallocz(size_t size)
|
|
{
|
|
return do_xmallocz(size, 0);
|
|
}
|
|
|
|
void *xmallocz_gently(size_t size)
|
|
{
|
|
return do_xmallocz(size, 1);
|
|
}
|
|
|
|
/*
|
|
* 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, 0);
|
|
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;
|
|
|
|
if (unsigned_mult_overflows(nmemb, size))
|
|
die("data too large to fit into virtual memory space");
|
|
|
|
memory_limit_check(size * nmemb, 0);
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* Limit size of IO chunks, because huge chunks only cause pain. OS X
|
|
* 64-bit is buggy, returning EINVAL if len >= INT_MAX; and even in
|
|
* the absence of bugs, large chunks can result in bad latencies when
|
|
* you decide to kill the process.
|
|
*
|
|
* We pick 8 MiB as our default, but if the platform defines SSIZE_MAX
|
|
* that is smaller than that, clip it to SSIZE_MAX, as a call to
|
|
* read(2) or write(2) larger than that is allowed to fail. As the last
|
|
* resort, we allow a port to pass via CFLAGS e.g. "-DMAX_IO_SIZE=value"
|
|
* to override this, if the definition of SSIZE_MAX given by the platform
|
|
* is broken.
|
|
*/
|
|
#ifndef MAX_IO_SIZE
|
|
# define MAX_IO_SIZE_DEFAULT (8*1024*1024)
|
|
# if defined(SSIZE_MAX) && (SSIZE_MAX < MAX_IO_SIZE_DEFAULT)
|
|
# define MAX_IO_SIZE SSIZE_MAX
|
|
# else
|
|
# define MAX_IO_SIZE MAX_IO_SIZE_DEFAULT
|
|
# endif
|
|
#endif
|
|
|
|
/**
|
|
* xopen() is the same as open(), but it die()s if the open() fails.
|
|
*/
|
|
int xopen(const char *path, int oflag, ...)
|
|
{
|
|
mode_t mode = 0;
|
|
va_list ap;
|
|
|
|
/*
|
|
* va_arg() will have undefined behavior if the specified type is not
|
|
* compatible with the argument type. Since integers are promoted to
|
|
* ints, we fetch the next argument as an int, and then cast it to a
|
|
* mode_t to avoid undefined behavior.
|
|
*/
|
|
va_start(ap, oflag);
|
|
if (oflag & O_CREAT)
|
|
mode = va_arg(ap, int);
|
|
va_end(ap);
|
|
|
|
for (;;) {
|
|
int fd = open(path, oflag, mode);
|
|
if (fd >= 0)
|
|
return fd;
|
|
if (errno == EINTR)
|
|
continue;
|
|
|
|
if ((oflag & O_RDWR) == O_RDWR)
|
|
die_errno(_("could not open '%s' for reading and writing"), path);
|
|
else if ((oflag & O_WRONLY) == O_WRONLY)
|
|
die_errno(_("could not open '%s' for writing"), path);
|
|
else
|
|
die_errno(_("could not open '%s' for reading"), path);
|
|
}
|
|
}
|
|
|
|
static int handle_nonblock(int fd, short poll_events, int err)
|
|
{
|
|
struct pollfd pfd;
|
|
|
|
if (err != EAGAIN && err != EWOULDBLOCK)
|
|
return 0;
|
|
|
|
pfd.fd = fd;
|
|
pfd.events = poll_events;
|
|
|
|
/*
|
|
* no need to check for errors, here;
|
|
* a subsequent read/write will detect unrecoverable errors
|
|
*/
|
|
poll(&pfd, 1, -1);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
if (len > MAX_IO_SIZE)
|
|
len = MAX_IO_SIZE;
|
|
while (1) {
|
|
nr = read(fd, buf, len);
|
|
if (nr < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
if (handle_nonblock(fd, POLLIN, errno))
|
|
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;
|
|
if (len > MAX_IO_SIZE)
|
|
len = MAX_IO_SIZE;
|
|
while (1) {
|
|
nr = write(fd, buf, len);
|
|
if (nr < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
if (handle_nonblock(fd, POLLOUT, errno))
|
|
continue;
|
|
}
|
|
|
|
return nr;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* xpread() is the same as pread(), but it automatically restarts pread()
|
|
* operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
|
|
* NOT GUARANTEE that "len" bytes is read even if the data is available.
|
|
*/
|
|
ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
|
|
{
|
|
ssize_t nr;
|
|
if (len > MAX_IO_SIZE)
|
|
len = MAX_IO_SIZE;
|
|
while (1) {
|
|
nr = pread(fd, buf, len, offset);
|
|
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;
|
|
}
|
|
|
|
ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
|
|
{
|
|
char *p = buf;
|
|
ssize_t total = 0;
|
|
|
|
while (count > 0) {
|
|
ssize_t loaded = xpread(fd, p, count, offset);
|
|
if (loaded < 0)
|
|
return -1;
|
|
if (loaded == 0)
|
|
return total;
|
|
count -= loaded;
|
|
p += loaded;
|
|
total += loaded;
|
|
offset += loaded;
|
|
}
|
|
|
|
return total;
|
|
}
|
|
|
|
int xdup(int fd)
|
|
{
|
|
int ret = dup(fd);
|
|
if (ret < 0)
|
|
die_errno("dup failed");
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* xfopen() is the same as fopen(), but it die()s if the fopen() fails.
|
|
*/
|
|
FILE *xfopen(const char *path, const char *mode)
|
|
{
|
|
for (;;) {
|
|
FILE *fp = fopen(path, mode);
|
|
if (fp)
|
|
return fp;
|
|
if (errno == EINTR)
|
|
continue;
|
|
|
|
if (*mode && mode[1] == '+')
|
|
die_errno(_("could not open '%s' for reading and writing"), path);
|
|
else if (*mode == 'w' || *mode == 'a')
|
|
die_errno(_("could not open '%s' for writing"), path);
|
|
else
|
|
die_errno(_("could not open '%s' for reading"), path);
|
|
}
|
|
}
|
|
|
|
FILE *xfdopen(int fd, const char *mode)
|
|
{
|
|
FILE *stream = fdopen(fd, mode);
|
|
if (stream == NULL)
|
|
die_errno("Out of memory? fdopen failed");
|
|
return stream;
|
|
}
|
|
|
|
FILE *fopen_for_writing(const char *path)
|
|
{
|
|
FILE *ret = fopen(path, "w");
|
|
|
|
if (!ret && errno == EPERM) {
|
|
if (!unlink(path))
|
|
ret = fopen(path, "w");
|
|
else
|
|
errno = EPERM;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void warn_on_inaccessible(const char *path)
|
|
{
|
|
warning_errno(_("unable to access '%s'"), path);
|
|
}
|
|
|
|
int warn_on_fopen_errors(const char *path)
|
|
{
|
|
if (errno != ENOENT && errno != ENOTDIR) {
|
|
warn_on_inaccessible(path);
|
|
return -1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
FILE *fopen_or_warn(const char *path, const char *mode)
|
|
{
|
|
FILE *fp = fopen(path, mode);
|
|
|
|
if (fp)
|
|
return fp;
|
|
|
|
warn_on_fopen_errors(path);
|
|
return NULL;
|
|
}
|
|
|
|
int xmkstemp(char *filename_template)
|
|
{
|
|
int fd;
|
|
char origtemplate[PATH_MAX];
|
|
strlcpy(origtemplate, filename_template, sizeof(origtemplate));
|
|
|
|
fd = mkstemp(filename_template);
|
|
if (fd < 0) {
|
|
int saved_errno = errno;
|
|
const char *nonrelative_template;
|
|
|
|
if (strlen(filename_template) != strlen(origtemplate))
|
|
filename_template = origtemplate;
|
|
|
|
nonrelative_template = absolute_path(filename_template);
|
|
errno = saved_errno;
|
|
die_errno("Unable to create temporary file '%s'",
|
|
nonrelative_template);
|
|
}
|
|
return fd;
|
|
}
|
|
|
|
/* 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 *filename_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();
|
|
filename_template = &pattern[len - 6 - suffix_len];
|
|
for (count = 0; count < TMP_MAX; ++count) {
|
|
uint64_t v = value;
|
|
/* Fill in the random bits. */
|
|
filename_template[0] = letters[v % num_letters]; v /= num_letters;
|
|
filename_template[1] = letters[v % num_letters]; v /= num_letters;
|
|
filename_template[2] = letters[v % num_letters]; v /= num_letters;
|
|
filename_template[3] = letters[v % num_letters]; v /= num_letters;
|
|
filename_template[4] = letters[v % num_letters]; v /= num_letters;
|
|
filename_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 xmkstemp_mode(char *filename_template, int mode)
|
|
{
|
|
int fd;
|
|
char origtemplate[PATH_MAX];
|
|
strlcpy(origtemplate, filename_template, sizeof(origtemplate));
|
|
|
|
fd = git_mkstemp_mode(filename_template, mode);
|
|
if (fd < 0) {
|
|
int saved_errno = errno;
|
|
const char *nonrelative_template;
|
|
|
|
if (!filename_template[0])
|
|
filename_template = origtemplate;
|
|
|
|
nonrelative_template = absolute_path(filename_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)
|
|
{
|
|
int err;
|
|
if (!rc || errno == ENOENT)
|
|
return 0;
|
|
err = errno;
|
|
warning_errno("unable to %s '%s'", op, file);
|
|
errno = err;
|
|
return rc;
|
|
}
|
|
|
|
int unlink_or_msg(const char *file, struct strbuf *err)
|
|
{
|
|
int rc = unlink(file);
|
|
|
|
assert(err);
|
|
|
|
if (!rc || errno == ENOENT)
|
|
return 0;
|
|
|
|
strbuf_addf(err, "unable to unlink '%s': %s",
|
|
file, strerror(errno));
|
|
return -1;
|
|
}
|
|
|
|
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);
|
|
}
|
|
|
|
static int access_error_is_ok(int err, unsigned flag)
|
|
{
|
|
return (is_missing_file_error(err) ||
|
|
((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;
|
|
}
|
|
|
|
char *xgetcwd(void)
|
|
{
|
|
struct strbuf sb = STRBUF_INIT;
|
|
if (strbuf_getcwd(&sb))
|
|
die_errno(_("unable to get current working directory"));
|
|
return strbuf_detach(&sb, NULL);
|
|
}
|
|
|
|
int xsnprintf(char *dst, size_t max, const char *fmt, ...)
|
|
{
|
|
va_list ap;
|
|
int len;
|
|
|
|
va_start(ap, fmt);
|
|
len = vsnprintf(dst, max, fmt, ap);
|
|
va_end(ap);
|
|
|
|
if (len < 0)
|
|
BUG("your snprintf is broken");
|
|
if (len >= max)
|
|
BUG("attempt to snprintf into too-small buffer");
|
|
return len;
|
|
}
|
|
|
|
void write_file_buf(const char *path, const char *buf, size_t len)
|
|
{
|
|
int fd = xopen(path, O_WRONLY | O_CREAT | O_TRUNC, 0666);
|
|
if (write_in_full(fd, buf, len) < 0)
|
|
die_errno(_("could not write to '%s'"), path);
|
|
if (close(fd))
|
|
die_errno(_("could not close '%s'"), path);
|
|
}
|
|
|
|
void write_file(const char *path, const char *fmt, ...)
|
|
{
|
|
va_list params;
|
|
struct strbuf sb = STRBUF_INIT;
|
|
|
|
va_start(params, fmt);
|
|
strbuf_vaddf(&sb, fmt, params);
|
|
va_end(params);
|
|
|
|
strbuf_complete_line(&sb);
|
|
|
|
write_file_buf(path, sb.buf, sb.len);
|
|
strbuf_release(&sb);
|
|
}
|
|
|
|
void sleep_millisec(int millisec)
|
|
{
|
|
poll(NULL, 0, millisec);
|
|
}
|
|
|
|
int xgethostname(char *buf, size_t len)
|
|
{
|
|
/*
|
|
* If the full hostname doesn't fit in buf, POSIX does not
|
|
* specify whether the buffer will be null-terminated, so to
|
|
* be safe, do it ourselves.
|
|
*/
|
|
int ret = gethostname(buf, len);
|
|
if (!ret)
|
|
buf[len - 1] = 0;
|
|
return ret;
|
|
}
|
|
|
|
int is_empty_or_missing_file(const char *filename)
|
|
{
|
|
struct stat st;
|
|
|
|
if (stat(filename, &st) < 0) {
|
|
if (errno == ENOENT)
|
|
return 1;
|
|
die_errno(_("could not stat %s"), filename);
|
|
}
|
|
|
|
return !st.st_size;
|
|
}
|