git/wrapper.c
Junio C Hamano 11529ecec9 Merge branch 'jk/tighten-alloc'
Update various codepaths to avoid manually-counted malloc().

* jk/tighten-alloc: (22 commits)
  ewah: convert to REALLOC_ARRAY, etc
  convert ewah/bitmap code to use xmalloc
  diff_populate_gitlink: use a strbuf
  transport_anonymize_url: use xstrfmt
  git-compat-util: drop mempcpy compat code
  sequencer: simplify memory allocation of get_message
  test-path-utils: fix normalize_path_copy output buffer size
  fetch-pack: simplify add_sought_entry
  fast-import: simplify allocation in start_packfile
  write_untracked_extension: use FLEX_ALLOC helper
  prepare_{git,shell}_cmd: use argv_array
  use st_add and st_mult for allocation size computation
  convert trivial cases to FLEX_ARRAY macros
  use xmallocz to avoid size arithmetic
  convert trivial cases to ALLOC_ARRAY
  convert manual allocations to argv_array
  argv-array: add detach function
  add helpers for allocating flex-array structs
  harden REALLOC_ARRAY and xcalloc against size_t overflow
  tree-diff: catch integer overflow in combine_diff_path allocation
  ...
2016-02-26 13:37:16 -08:00

716 lines
15 KiB
C

/*
* 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 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);
}
}
/*
* 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 (errno == EAGAIN || errno == EWOULDBLOCK) {
struct pollfd pfd;
pfd.events = POLLIN;
pfd.fd = fd;
/*
* it is OK if this poll() failed; we
* want to leave this infinite loop
* only when read() returns with
* success, or an expected failure,
* which would be checked by the next
* call to read(2).
*/
poll(&pfd, 1, -1);
}
}
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) && (errno == EAGAIN || errno == EINTR))
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;
}
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);
}
#ifdef NO_MKSTEMPS
int gitmkstemps(char *pattern, int suffix_len)
{
return git_mkstemps_mode(pattern, suffix_len, 0600);
}
#endif
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)
{
int err;
if (!rc || errno == ENOENT)
return 0;
err = errno;
warning("unable to %s %s: %s", op, file, strerror(errno));
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);
}
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;
}
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)
die("BUG: your snprintf is broken");
if (len >= max)
die("BUG: attempt to snprintf into too-small buffer");
return len;
}
static int write_file_v(const char *path, int fatal,
const char *fmt, va_list params)
{
struct strbuf sb = STRBUF_INIT;
int fd = open(path, O_RDWR | O_CREAT | O_TRUNC, 0666);
if (fd < 0) {
if (fatal)
die_errno(_("could not open %s for writing"), path);
return -1;
}
strbuf_vaddf(&sb, fmt, params);
strbuf_complete_line(&sb);
if (write_in_full(fd, sb.buf, sb.len) != sb.len) {
int err = errno;
close(fd);
strbuf_release(&sb);
errno = err;
if (fatal)
die_errno(_("could not write to %s"), path);
return -1;
}
strbuf_release(&sb);
if (close(fd)) {
if (fatal)
die_errno(_("could not close %s"), path);
return -1;
}
return 0;
}
int write_file(const char *path, const char *fmt, ...)
{
int status;
va_list params;
va_start(params, fmt);
status = write_file_v(path, 1, fmt, params);
va_end(params);
return status;
}
int write_file_gently(const char *path, const char *fmt, ...)
{
int status;
va_list params;
va_start(params, fmt);
status = write_file_v(path, 0, fmt, params);
va_end(params);
return status;
}
void sleep_millisec(int millisec)
{
poll(NULL, 0, millisec);
}