mirror of
https://github.com/git/git
synced 2024-08-28 12:09:19 +00:00
![Elijah Newren](/assets/img/avatar_default.png)
Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
838 lines
17 KiB
C
838 lines
17 KiB
C
/*
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* Various trivial helper wrappers around standard functions
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*/
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#include "git-compat-util.h"
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#include "abspath.h"
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#include "config.h"
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#include "gettext.h"
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#include "object.h"
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#include "repository.h"
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#include "strbuf.h"
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#include "trace2.h"
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#include "wrapper.h"
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static intmax_t count_fsync_writeout_only;
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static intmax_t count_fsync_hardware_flush;
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#ifdef HAVE_RTLGENRANDOM
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/* This is required to get access to RtlGenRandom. */
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#define SystemFunction036 NTAPI SystemFunction036
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#include <NTSecAPI.h>
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#undef SystemFunction036
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#endif
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static int memory_limit_check(size_t size, int gentle)
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{
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static size_t limit = 0;
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if (!limit) {
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limit = git_env_ulong("GIT_ALLOC_LIMIT", 0);
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if (!limit)
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limit = SIZE_MAX;
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}
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if (size > limit) {
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if (gentle) {
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error("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
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(uintmax_t)size, (uintmax_t)limit);
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return -1;
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} else
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die("attempting to allocate %"PRIuMAX" over limit %"PRIuMAX,
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(uintmax_t)size, (uintmax_t)limit);
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}
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return 0;
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}
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char *xstrdup(const char *str)
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{
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char *ret = strdup(str);
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if (!ret)
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die("Out of memory, strdup failed");
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return ret;
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}
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static void *do_xmalloc(size_t size, int gentle)
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{
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void *ret;
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if (memory_limit_check(size, gentle))
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return NULL;
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ret = malloc(size);
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if (!ret && !size)
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ret = malloc(1);
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if (!ret) {
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if (!gentle)
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die("Out of memory, malloc failed (tried to allocate %lu bytes)",
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(unsigned long)size);
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else {
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error("Out of memory, malloc failed (tried to allocate %lu bytes)",
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(unsigned long)size);
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return NULL;
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}
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}
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#ifdef XMALLOC_POISON
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memset(ret, 0xA5, size);
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#endif
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return ret;
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}
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void *xmalloc(size_t size)
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{
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return do_xmalloc(size, 0);
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}
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static void *do_xmallocz(size_t size, int gentle)
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{
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void *ret;
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if (unsigned_add_overflows(size, 1)) {
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if (gentle) {
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error("Data too large to fit into virtual memory space.");
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return NULL;
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} else
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die("Data too large to fit into virtual memory space.");
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}
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ret = do_xmalloc(size + 1, gentle);
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if (ret)
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((char*)ret)[size] = 0;
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return ret;
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}
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void *xmallocz(size_t size)
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{
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return do_xmallocz(size, 0);
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}
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void *xmallocz_gently(size_t size)
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{
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return do_xmallocz(size, 1);
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}
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/*
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* xmemdupz() allocates (len + 1) bytes of memory, duplicates "len" bytes of
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* "data" to the allocated memory, zero terminates the allocated memory,
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* and returns a pointer to the allocated memory. If the allocation fails,
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* the program dies.
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*/
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void *xmemdupz(const void *data, size_t len)
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{
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return memcpy(xmallocz(len), data, len);
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}
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char *xstrndup(const char *str, size_t len)
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{
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char *p = memchr(str, '\0', len);
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return xmemdupz(str, p ? p - str : len);
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}
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int xstrncmpz(const char *s, const char *t, size_t len)
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{
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int res = strncmp(s, t, len);
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if (res)
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return res;
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return s[len] == '\0' ? 0 : 1;
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}
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void *xrealloc(void *ptr, size_t size)
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{
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void *ret;
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if (!size) {
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free(ptr);
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return xmalloc(0);
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}
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memory_limit_check(size, 0);
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ret = realloc(ptr, size);
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if (!ret)
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die("Out of memory, realloc failed");
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return ret;
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}
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void *xcalloc(size_t nmemb, size_t size)
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{
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void *ret;
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if (unsigned_mult_overflows(nmemb, size))
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die("data too large to fit into virtual memory space");
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memory_limit_check(size * nmemb, 0);
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ret = calloc(nmemb, size);
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if (!ret && (!nmemb || !size))
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ret = calloc(1, 1);
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if (!ret)
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die("Out of memory, calloc failed");
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return ret;
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}
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void xsetenv(const char *name, const char *value, int overwrite)
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{
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if (setenv(name, value, overwrite))
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die_errno(_("could not setenv '%s'"), name ? name : "(null)");
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}
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/**
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* xopen() is the same as open(), but it die()s if the open() fails.
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*/
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int xopen(const char *path, int oflag, ...)
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{
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mode_t mode = 0;
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va_list ap;
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/*
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* va_arg() will have undefined behavior if the specified type is not
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* compatible with the argument type. Since integers are promoted to
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* ints, we fetch the next argument as an int, and then cast it to a
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* mode_t to avoid undefined behavior.
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*/
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va_start(ap, oflag);
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if (oflag & O_CREAT)
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mode = va_arg(ap, int);
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va_end(ap);
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for (;;) {
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int fd = open(path, oflag, mode);
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if (fd >= 0)
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return fd;
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if (errno == EINTR)
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continue;
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if ((oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
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die_errno(_("unable to create '%s'"), path);
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else if ((oflag & O_RDWR) == O_RDWR)
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die_errno(_("could not open '%s' for reading and writing"), path);
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else if ((oflag & O_WRONLY) == O_WRONLY)
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die_errno(_("could not open '%s' for writing"), path);
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else
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die_errno(_("could not open '%s' for reading"), path);
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}
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}
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static int handle_nonblock(int fd, short poll_events, int err)
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{
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struct pollfd pfd;
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if (err != EAGAIN && err != EWOULDBLOCK)
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return 0;
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pfd.fd = fd;
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pfd.events = poll_events;
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/*
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* no need to check for errors, here;
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* a subsequent read/write will detect unrecoverable errors
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*/
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poll(&pfd, 1, -1);
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return 1;
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}
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/*
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* xread() is the same a read(), but it automatically restarts read()
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* operations with a recoverable error (EAGAIN and EINTR). xread()
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* DOES NOT GUARANTEE that "len" bytes is read even if the data is available.
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*/
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ssize_t xread(int fd, void *buf, size_t len)
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{
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ssize_t nr;
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if (len > MAX_IO_SIZE)
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len = MAX_IO_SIZE;
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while (1) {
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nr = read(fd, buf, len);
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if (nr < 0) {
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if (errno == EINTR)
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continue;
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if (handle_nonblock(fd, POLLIN, errno))
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continue;
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}
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return nr;
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}
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}
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/*
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* xwrite() is the same a write(), but it automatically restarts write()
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* operations with a recoverable error (EAGAIN and EINTR). xwrite() DOES NOT
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* GUARANTEE that "len" bytes is written even if the operation is successful.
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*/
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ssize_t xwrite(int fd, const void *buf, size_t len)
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{
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ssize_t nr;
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if (len > MAX_IO_SIZE)
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len = MAX_IO_SIZE;
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while (1) {
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nr = write(fd, buf, len);
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if (nr < 0) {
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if (errno == EINTR)
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continue;
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if (handle_nonblock(fd, POLLOUT, errno))
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continue;
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}
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return nr;
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}
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}
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/*
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* xpread() is the same as pread(), but it automatically restarts pread()
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* operations with a recoverable error (EAGAIN and EINTR). xpread() DOES
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* NOT GUARANTEE that "len" bytes is read even if the data is available.
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*/
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ssize_t xpread(int fd, void *buf, size_t len, off_t offset)
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{
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ssize_t nr;
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if (len > MAX_IO_SIZE)
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len = MAX_IO_SIZE;
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while (1) {
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nr = pread(fd, buf, len, offset);
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if ((nr < 0) && (errno == EAGAIN || errno == EINTR))
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continue;
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return nr;
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}
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}
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ssize_t read_in_full(int fd, void *buf, size_t count)
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{
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char *p = buf;
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ssize_t total = 0;
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while (count > 0) {
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ssize_t loaded = xread(fd, p, count);
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if (loaded < 0)
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return -1;
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if (loaded == 0)
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return total;
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count -= loaded;
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p += loaded;
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total += loaded;
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}
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return total;
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}
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ssize_t write_in_full(int fd, const void *buf, size_t count)
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{
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const char *p = buf;
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ssize_t total = 0;
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while (count > 0) {
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ssize_t written = xwrite(fd, p, count);
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if (written < 0)
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return -1;
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if (!written) {
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errno = ENOSPC;
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return -1;
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}
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count -= written;
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p += written;
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total += written;
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}
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return total;
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}
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ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset)
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{
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char *p = buf;
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ssize_t total = 0;
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while (count > 0) {
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ssize_t loaded = xpread(fd, p, count, offset);
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if (loaded < 0)
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return -1;
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if (loaded == 0)
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return total;
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count -= loaded;
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p += loaded;
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total += loaded;
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offset += loaded;
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}
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return total;
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}
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int xdup(int fd)
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{
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int ret = dup(fd);
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if (ret < 0)
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die_errno("dup failed");
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return ret;
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}
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/**
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* xfopen() is the same as fopen(), but it die()s if the fopen() fails.
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*/
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FILE *xfopen(const char *path, const char *mode)
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{
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for (;;) {
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FILE *fp = fopen(path, mode);
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if (fp)
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return fp;
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if (errno == EINTR)
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continue;
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if (*mode && mode[1] == '+')
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die_errno(_("could not open '%s' for reading and writing"), path);
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else if (*mode == 'w' || *mode == 'a')
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die_errno(_("could not open '%s' for writing"), path);
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else
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die_errno(_("could not open '%s' for reading"), path);
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}
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}
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FILE *xfdopen(int fd, const char *mode)
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{
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FILE *stream = fdopen(fd, mode);
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if (!stream)
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die_errno("Out of memory? fdopen failed");
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return stream;
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}
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FILE *fopen_for_writing(const char *path)
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{
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FILE *ret = fopen(path, "w");
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if (!ret && errno == EPERM) {
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if (!unlink(path))
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ret = fopen(path, "w");
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else
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errno = EPERM;
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}
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return ret;
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}
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static void warn_on_inaccessible(const char *path)
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{
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warning_errno(_("unable to access '%s'"), path);
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}
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int warn_on_fopen_errors(const char *path)
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{
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if (errno != ENOENT && errno != ENOTDIR) {
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warn_on_inaccessible(path);
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return -1;
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}
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return 0;
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}
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FILE *fopen_or_warn(const char *path, const char *mode)
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{
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FILE *fp = fopen(path, mode);
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if (fp)
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return fp;
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warn_on_fopen_errors(path);
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return NULL;
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}
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int xmkstemp(char *filename_template)
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{
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int fd;
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char origtemplate[PATH_MAX];
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strlcpy(origtemplate, filename_template, sizeof(origtemplate));
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fd = mkstemp(filename_template);
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if (fd < 0) {
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int saved_errno = errno;
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const char *nonrelative_template;
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if (strlen(filename_template) != strlen(origtemplate))
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filename_template = origtemplate;
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nonrelative_template = absolute_path(filename_template);
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errno = saved_errno;
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die_errno("Unable to create temporary file '%s'",
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nonrelative_template);
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}
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return fd;
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}
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/* Adapted from libiberty's mkstemp.c. */
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#undef TMP_MAX
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#define TMP_MAX 16384
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int git_mkstemps_mode(char *pattern, int suffix_len, int mode)
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{
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static const char letters[] =
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"abcdefghijklmnopqrstuvwxyz"
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"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
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"0123456789";
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static const int num_letters = ARRAY_SIZE(letters) - 1;
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static const char x_pattern[] = "XXXXXX";
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static const int num_x = ARRAY_SIZE(x_pattern) - 1;
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char *filename_template;
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size_t len;
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int fd, count;
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len = strlen(pattern);
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if (len < num_x + suffix_len) {
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errno = EINVAL;
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return -1;
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}
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if (strncmp(&pattern[len - num_x - suffix_len], x_pattern, num_x)) {
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errno = EINVAL;
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return -1;
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}
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/*
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* Replace pattern's XXXXXX characters with randomness.
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* Try TMP_MAX different filenames.
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*/
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filename_template = &pattern[len - num_x - suffix_len];
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for (count = 0; count < TMP_MAX; ++count) {
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int i;
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uint64_t v;
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if (csprng_bytes(&v, sizeof(v)) < 0)
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return error_errno("unable to get random bytes for temporary file");
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/* Fill in the random bits. */
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for (i = 0; i < num_x; i++) {
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filename_template[i] = letters[v % num_letters];
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v /= num_letters;
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}
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fd = open(pattern, O_CREAT | O_EXCL | O_RDWR, mode);
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if (fd >= 0)
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return fd;
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/*
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* Fatal error (EPERM, ENOSPC etc).
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* It doesn't make sense to loop.
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*/
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if (errno != EEXIST)
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break;
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}
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/* We return the null string if we can't find a unique file name. */
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pattern[0] = '\0';
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return -1;
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}
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int git_mkstemp_mode(char *pattern, int mode)
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{
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/* mkstemp is just mkstemps with no suffix */
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return git_mkstemps_mode(pattern, 0, mode);
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}
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int xmkstemp_mode(char *filename_template, int mode)
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{
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int fd;
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char origtemplate[PATH_MAX];
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strlcpy(origtemplate, filename_template, sizeof(origtemplate));
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fd = git_mkstemp_mode(filename_template, mode);
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if (fd < 0) {
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int saved_errno = errno;
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const char *nonrelative_template;
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if (!filename_template[0])
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filename_template = origtemplate;
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nonrelative_template = absolute_path(filename_template);
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errno = saved_errno;
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die_errno("Unable to create temporary file '%s'",
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nonrelative_template);
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}
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return fd;
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}
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/*
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* Some platforms return EINTR from fsync. Since fsync is invoked in some
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* cases by a wrapper that dies on failure, do not expose EINTR to callers.
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*/
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static int fsync_loop(int fd)
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{
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int err;
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do {
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err = fsync(fd);
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} while (err < 0 && errno == EINTR);
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return err;
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}
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int git_fsync(int fd, enum fsync_action action)
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{
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switch (action) {
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case FSYNC_WRITEOUT_ONLY:
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count_fsync_writeout_only += 1;
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#ifdef __APPLE__
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/*
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* On macOS, fsync just causes filesystem cache writeback but
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* does not flush hardware caches.
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*/
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return fsync_loop(fd);
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#endif
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#ifdef HAVE_SYNC_FILE_RANGE
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/*
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|
* On linux 2.6.17 and above, sync_file_range is the way to
|
|
* issue a writeback without a hardware flush. An offset of
|
|
* 0 and size of 0 indicates writeout of the entire file and the
|
|
* wait flags ensure that all dirty data is written to the disk
|
|
* (potentially in a disk-side cache) before we continue.
|
|
*/
|
|
|
|
return sync_file_range(fd, 0, 0, SYNC_FILE_RANGE_WAIT_BEFORE |
|
|
SYNC_FILE_RANGE_WRITE |
|
|
SYNC_FILE_RANGE_WAIT_AFTER);
|
|
#endif
|
|
|
|
#ifdef fsync_no_flush
|
|
return fsync_no_flush(fd);
|
|
#endif
|
|
|
|
errno = ENOSYS;
|
|
return -1;
|
|
|
|
case FSYNC_HARDWARE_FLUSH:
|
|
count_fsync_hardware_flush += 1;
|
|
|
|
/*
|
|
* On macOS, a special fcntl is required to really flush the
|
|
* caches within the storage controller. As of this writing,
|
|
* this is a very expensive operation on Apple SSDs.
|
|
*/
|
|
#ifdef __APPLE__
|
|
return fcntl(fd, F_FULLFSYNC);
|
|
#else
|
|
return fsync_loop(fd);
|
|
#endif
|
|
default:
|
|
BUG("unexpected git_fsync(%d) call", action);
|
|
}
|
|
}
|
|
|
|
static void log_trace_fsync_if(const char *key, intmax_t value)
|
|
{
|
|
if (value)
|
|
trace2_data_intmax("fsync", the_repository, key, value);
|
|
}
|
|
|
|
void trace_git_fsync_stats(void)
|
|
{
|
|
log_trace_fsync_if("fsync/writeout-only", count_fsync_writeout_only);
|
|
log_trace_fsync_if("fsync/hardware-flush", count_fsync_hardware_flush);
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
int open_nofollow(const char *path, int flags)
|
|
{
|
|
#ifdef O_NOFOLLOW
|
|
return open(path, flags | O_NOFOLLOW);
|
|
#else
|
|
struct stat st;
|
|
if (lstat(path, &st) < 0)
|
|
return -1;
|
|
if (S_ISLNK(st.st_mode)) {
|
|
errno = ELOOP;
|
|
return -1;
|
|
}
|
|
return open(path, flags);
|
|
#endif
|
|
}
|
|
|
|
int csprng_bytes(void *buf, size_t len)
|
|
{
|
|
#if defined(HAVE_ARC4RANDOM) || defined(HAVE_ARC4RANDOM_LIBBSD)
|
|
/* This function never returns an error. */
|
|
arc4random_buf(buf, len);
|
|
return 0;
|
|
#elif defined(HAVE_GETRANDOM)
|
|
ssize_t res;
|
|
char *p = buf;
|
|
while (len) {
|
|
res = getrandom(p, len, 0);
|
|
if (res < 0)
|
|
return -1;
|
|
len -= res;
|
|
p += res;
|
|
}
|
|
return 0;
|
|
#elif defined(HAVE_GETENTROPY)
|
|
int res;
|
|
char *p = buf;
|
|
while (len) {
|
|
/* getentropy has a maximum size of 256 bytes. */
|
|
size_t chunk = len < 256 ? len : 256;
|
|
res = getentropy(p, chunk);
|
|
if (res < 0)
|
|
return -1;
|
|
len -= chunk;
|
|
p += chunk;
|
|
}
|
|
return 0;
|
|
#elif defined(HAVE_RTLGENRANDOM)
|
|
if (!RtlGenRandom(buf, len))
|
|
return -1;
|
|
return 0;
|
|
#elif defined(HAVE_OPENSSL_CSPRNG)
|
|
int res = RAND_bytes(buf, len);
|
|
if (res == 1)
|
|
return 0;
|
|
if (res == -1)
|
|
errno = ENOTSUP;
|
|
else
|
|
errno = EIO;
|
|
return -1;
|
|
#else
|
|
ssize_t res;
|
|
char *p = buf;
|
|
int fd, err;
|
|
fd = open("/dev/urandom", O_RDONLY);
|
|
if (fd < 0)
|
|
return -1;
|
|
while (len) {
|
|
res = xread(fd, p, len);
|
|
if (res < 0) {
|
|
err = errno;
|
|
close(fd);
|
|
errno = err;
|
|
return -1;
|
|
}
|
|
len -= res;
|
|
p += res;
|
|
}
|
|
close(fd);
|
|
return 0;
|
|
#endif
|
|
}
|