src/lxc/file_utils.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2
   3 #ifndef __LXC_FILE_UTILS_H
   4 #define __LXC_FILE_UTILS_H
   5
   6 #include "config.h"
   7
   8 #include <fcntl.h>
   9 #include <stdbool.h>
  10 #include <stdio.h>
  11 #include <sys/stat.h>
  12 #include <sys/types.h>
  13 #include <sys/uio.h>
  14 #include <sys/vfs.h>
  15 #include <unistd.h>
  16
  17 #include "compiler.h"
  18 #include "memory_utils.h"
  19 #include "syscall_wrappers.h"
  20
  21 /* read and write whole files */
  22 __hidden extern int lxc_write_to_file(const char *filename, const void *buf, size_t count,
  23                                       bool add_newline, mode_t mode) __access_r(2, 3);
  24
  25 __hidden extern int lxc_readat(int dirfd, const char *filename, void *buf, size_t count)
  26     __access_w(3, 4);
  27
  28 __hidden extern int lxc_writeat(int dirfd, const char *filename, const void *buf, size_t count)
  29     __access_r(3, 4);
  30
  31 __hidden extern int lxc_write_openat(const char *dir, const char *filename, const void *buf,
  32                                      size_t count) __access_r(3, 4);
  33
  34 __hidden extern int lxc_read_from_file(const char *filename, void *buf, size_t count)
  35     __access_w(2, 3);
  36
  37 /* send and receive buffers completely */
  38 __hidden extern ssize_t lxc_write_nointr(int fd, const void *buf, size_t count) __access_r(2, 3);
  39
  40 __hidden extern ssize_t lxc_pwrite_nointr(int fd, const void *buf, size_t count, off_t offset)
  41     __access_r(2, 3);
  42
  43 __hidden extern ssize_t lxc_send_nointr(int sockfd, void *buf, size_t len, int flags)
  44     __access_r(2, 3);
  45
  46 __hidden extern ssize_t lxc_read_nointr(int fd, void *buf, size_t count) __access_w(2, 3);
  47
  48 __access_w(2, 3) static inline int lxc_read_string_nointr(int fd, char *buf,
  49                                                           size_t count)
  50 {
  51         ssize_t ret;
  52
  53         ret = lxc_read_nointr(fd, buf, STRARRAYLEN(buf));
  54         if (ret < 0)
  55                 return -errno;
  56         if (ret == 0)
  57                 return ret_errno(ENODATA);
  58         if ((size_t)ret >= sizeof(buf))
  59                 return ret_errno(E2BIG);
  60         buf[ret] = '\0';
  61         return 0;
  62 }
  63
  64 __hidden extern ssize_t lxc_read_nointr_expect(int fd, void *buf, size_t count,
  65                                                const void *expected_buf) __access_w(2, 3);
  66
  67 __hidden extern ssize_t lxc_read_file_expect(const char *path, void *buf, size_t count,
  68                                              const void *expected_buf) __access_w(2, 3);
  69
  70 __hidden extern ssize_t lxc_recv_nointr(int sockfd, void *buf, size_t len, int flags)
  71     __access_w(2, 3);
  72
  73 __hidden extern ssize_t lxc_recvmsg_nointr_iov(int sockfd, struct iovec *iov, size_t iovlen,
  74                                                int flags);
  75
  76 __hidden extern bool file_exists(const char *f);
  77 __hidden extern int print_to_file(const char *file, const char *content);
  78 __hidden extern int is_dir(const char *path);
  79 __hidden extern int lxc_count_file_lines(const char *fn);
  80 __hidden extern int lxc_make_tmpfile(char *template, bool rm);
  81
  82 /* __typeof__ should be safe to use with all compilers. */
  83 typedef __typeof__(((struct statfs *)NULL)->f_type) fs_type_magic;
  84 __hidden extern bool has_fs_type(const char *path, fs_type_magic magic_val);
  85 __hidden extern bool fhas_fs_type(int fd, fs_type_magic magic_val);
  86 __hidden extern bool is_fs_type(const struct statfs *fs, fs_type_magic magic_val);
  87 __hidden extern FILE *fopen_cloexec(const char *path, const char *mode);
  88 __hidden extern ssize_t lxc_sendfile_nointr(int out_fd, int in_fd, off_t *offset, size_t count);
  89 __hidden extern char *file_to_buf(const char *path, size_t *length);
  90 __hidden extern int fd_to_buf(int fd, char **buf, size_t *length);
  91 __hidden extern ssize_t __fd_to_fd(int from, int to);
  92 static inline int fd_to_fd(int from, int to)
  93 {
  94         return __fd_to_fd(from, to) >= 0;
  95 }
  96 __hidden extern int fd_cloexec(int fd, bool cloexec);
  97 __hidden extern int lxc_open_dirfd(const char *dir);
  98 __hidden extern FILE *fdopen_cached(int fd, const char *mode, void **caller_freed_buffer);
  99 __hidden extern FILE *fdopen_at(int dfd, const char *path, const char *mode,
 100                                 unsigned int o_flags,
 101                                 unsigned int resolve_flags);
 102 __hidden extern FILE *fopen_cached(const char *path, const char *mode, void **caller_freed_buffer);
 103 __hidden extern int timens_offset_write(clockid_t clk_id, int64_t s_offset, int64_t ns_offset);
 104 __hidden extern bool exists_dir_at(int dir_fd, const char *path);
 105 __hidden extern bool exists_file_at(int dir_fd, const char *path);
 106 __hidden extern int open_at(int dfd, const char *path, unsigned int o_flags,
 107                             unsigned int resolve_flags, mode_t mode);
 108 __hidden extern int open_at_same(int fd_same, int dfd, const char *path,
 109                                  unsigned int o_flags,
 110                                  unsigned int resolve_flags, mode_t mode);
 111 __hidden extern int open_beneath(int dfd, const char *path, unsigned int flags);
 112 __hidden int fd_make_nonblocking(int fd);
 113 __hidden extern char *read_file_at(int dfd, const char *fnam,
 114                                    unsigned int o_flags,
 115                                    unsigned resolve_flags);
 116 __hidden extern ssize_t lxc_read_try_buf_at(int dfd, const char *path,
 117                                             void *buf, size_t count);
 118
 119 /*
 120  * Check if two fds refer to the same file.
 121  * The function is "lax" in so far, as it doesn't care whether fda and fdb have
 122  * the same flags or whether they share the same device context when they refer
 123  * to devices.
 124  */
 125 __hidden extern bool same_file_lax(int fda, int fdb);
 126
 127 static inline int dup_cloexec(int fd)
 128 {
 129         __do_close int fd_dup = -EBADF;
 130
 131         fd_dup = dup(fd);
 132         if (fd_dup < 0)
 133                 return -errno;
 134
 135         if (fd_cloexec(fd_dup, true))
 136                 return -errno;
 137
 138         return move_fd(fd_dup);
 139 }
 140
 141 __hidden extern bool same_device(int fda, const char *patha, int fdb,
 142                                  const char *pathb);
 143
 144 #endif /* __LXC_FILE_UTILS_H */