wrapper.h

   1 #ifndef WRAPPER_H
   2 #define WRAPPER_H
   3
   4 char *xstrdup(const char *str);
   5 void *xmalloc(size_t size);
   6 void *xmallocz(size_t size);
   7 void *xmallocz_gently(size_t size);
   8 void *xmemdupz(const void *data, size_t len);
   9 char *xstrndup(const char *str, size_t len);
  10 void *xrealloc(void *ptr, size_t size);
  11 void *xcalloc(size_t nmemb, size_t size);
  12 void xsetenv(const char *name, const char *value, int overwrite);
  13 void *xmmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);
  14 const char *mmap_os_err(void);
  15 void *xmmap_gently(void *start, size_t length, int prot, int flags, int fd, off_t offset);
  16 int xopen(const char *path, int flags, ...);
  17 ssize_t xread(int fd, void *buf, size_t len);
  18 ssize_t xwrite(int fd, const void *buf, size_t len);
  19 ssize_t xpread(int fd, void *buf, size_t len, off_t offset);
  20 int xdup(int fd);
  21 FILE *xfopen(const char *path, const char *mode);
  22 FILE *xfdopen(int fd, const char *mode);
  23 int xmkstemp(char *temp_filename);
  24 int xmkstemp_mode(char *temp_filename, int mode);
  25 char *xgetcwd(void);
  26 FILE *fopen_for_writing(const char *path);
  27 FILE *fopen_or_warn(const char *path, const char *mode);
  28
  29 /*
  30  * Like strncmp, but only return zero if s is NUL-terminated and exactly len
  31  * characters long.  If it is not, consider it greater than t.
  32  */
  33 int xstrncmpz(const char *s, const char *t, size_t len);
  34
  35 __attribute__((format (printf, 3, 4)))
  36 int xsnprintf(char *dst, size_t max, const char *fmt, ...);
  37
  38 int xgethostname(char *buf, size_t len);
  39
  40 /* set default permissions by passing mode arguments to open(2) */
  41 int git_mkstemps_mode(char *pattern, int suffix_len, int mode);
  42 int git_mkstemp_mode(char *pattern, int mode);
  43
  44 ssize_t read_in_full(int fd, void *buf, size_t count);
  45 ssize_t write_in_full(int fd, const void *buf, size_t count);
  46 ssize_t pread_in_full(int fd, void *buf, size_t count, off_t offset);
  47
  48 static inline ssize_t write_str_in_full(int fd, const char *str)
  49 {
  50         return write_in_full(fd, str, strlen(str));
  51 }
  52
  53 /**
  54  * Open (and truncate) the file at path, write the contents of buf to it,
  55  * and close it. Dies if any errors are encountered.
  56  */
  57 void write_file_buf(const char *path, const char *buf, size_t len);
  58
  59 /**
  60  * Like write_file_buf(), but format the contents into a buffer first.
  61  * Additionally, write_file() will append a newline if one is not already
  62  * present, making it convenient to write text files:
  63  *
  64  *   write_file(path, "counter: %d", ctr);
  65  */
  66 __attribute__((format (printf, 2, 3)))
  67 void write_file(const char *path, const char *fmt, ...);
  68
  69 /* Return 1 if the file is empty or does not exists, 0 otherwise. */
  70 int is_empty_or_missing_file(const char *filename);
  71
  72 enum fsync_action {
  73         FSYNC_WRITEOUT_ONLY,
  74         FSYNC_HARDWARE_FLUSH
  75 };
  76
  77 /*
  78  * Issues an fsync against the specified file according to the specified mode.
  79  *
  80  * FSYNC_WRITEOUT_ONLY attempts to use interfaces available on some operating
  81  * systems to flush the OS cache without issuing a flush command to the storage
  82  * controller. If those interfaces are unavailable, the function fails with
  83  * ENOSYS.
  84  *
  85  * FSYNC_HARDWARE_FLUSH does an OS writeout and hardware flush to ensure that
  86  * changes are durable. It is not expected to fail.
  87  */
  88 int git_fsync(int fd, enum fsync_action action);
  89
  90 /*
  91  * Preserves errno, prints a message, but gives no warning for ENOENT.
  92  * Returns 0 on success, which includes trying to unlink an object that does
  93  * not exist.
  94  */
  95 int unlink_or_warn(const char *path);
  96  /*
  97   * Tries to unlink file.  Returns 0 if unlink succeeded
  98   * or the file already didn't exist.  Returns -1 and
  99   * appends a message to err suitable for
 100   * 'error("%s", err->buf)' on error.
 101   */
 102 int unlink_or_msg(const char *file, struct strbuf *err);
 103 /*
 104  * Preserves errno, prints a message, but gives no warning for ENOENT.
 105  * Returns 0 on success, which includes trying to remove a directory that does
 106  * not exist.
 107  */
 108 int rmdir_or_warn(const char *path);
 109
 110 /*
 111  * Call access(2), but warn for any error except "missing file"
 112  * (ENOENT or ENOTDIR).
 113  */
 114 #define ACCESS_EACCES_OK (1U << 0)
 115 int access_or_warn(const char *path, int mode, unsigned flag);
 116 int access_or_die(const char *path, int mode, unsigned flag);
 117
 118 /* Warn on an inaccessible file if errno indicates this is an error */
 119 int warn_on_fopen_errors(const char *path);
 120
 121 /*
 122  * Open with O_NOFOLLOW, or equivalent. Note that the fallback equivalent
 123  * may be racy. Do not use this as protection against an attacker who can
 124  * simultaneously create paths.
 125  */
 126 int open_nofollow(const char *path, int flags);
 127
 128 void sleep_millisec(int millisec);
 129
 130 /*
 131  * Generate len bytes from the system cryptographically secure PRNG.
 132  * Returns 0 on success and -1 on error, setting errno.  The inability to
 133  * satisfy the full request is an error.
 134  */
 135 int csprng_bytes(void *buf, size_t len);
 136
 137 /*
 138  * Returns a random uint32_t, uniformly distributed across all possible
 139  * values.
 140  */
 141 uint32_t git_rand(void);
 142
 143 /* Provide log2 of the given `size_t`. */
 144 static inline unsigned log2u(uintmax_t sz)
 145 {
 146         unsigned l = 0;
 147
 148         /*
 149          * Technically this isn't required, but it helps the compiler optimize
 150          * this to a `bsr` instruction.
 151          */
 152         if (!sz)
 153                 return 0;
 154
 155         for (; sz; sz >>= 1)
 156                 l++;
 157
 158         return l - 1;
 159 }
 160
 161 #endif /* WRAPPER_H */