Kill all remaining users of ERRNO_TO_ERROR().
[osl.git] / util.c
1 /*
2 * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file util.c Helper functions needed by both libosl and oslfsck. */
8
9 #include <sys/types.h>
10 #include <dirent.h>
11 #include <sys/mman.h>
12 #include <fcntl.h>
13 #include <sys/select.h>
14
15 #include "log.h"
16 #include "osl.h"
17 #include "error.h"
18 #include "util.h"
19
20 /**
21 * Wrapper for the write system call.
22 *
23 * \param fd The file descriptor to write to.
24 * \param buf The buffer to write.
25 * \param size The length of \a buf in bytes.
26 *
27 * This function writes out the given buffer and retries if an interrupt
28 * occurred during the write.
29 *
30 * \return On success, the number of bytes written is returned, otherwise, a
31 * negative error code is returned.
32 *
33 * \sa write(2).
34 */
35 static ssize_t __write(int fd, const void *buf, size_t size)
36 {
37 ssize_t ret;
38
39 for (;;) {
40 ret = write(fd, buf, size);
41 if ((ret < 0) && (errno == EAGAIN || errno == EINTR))
42 continue;
43 return ret >= 0? ret : -E_OSL_WRITE;
44 }
45 }
46
47 /**
48 * Write a buffer to a file descriptor, re-write on short writes.
49 *
50 * \param fd The file descriptor.
51 * \param buf The buffer to be sent.
52 * \param len The length of \a buf.
53 *
54 * \return Standard. In any case, the number of bytes that have been written is
55 * stored in \a len.
56 */
57 int write_all(int fd, const char *buf, size_t *len)
58 {
59 size_t total = *len;
60
61 assert(total);
62 *len = 0;
63 while (*len < total) {
64 int ret = __write(fd, buf + *len, total - *len);
65 if (ret < 0)
66 return ret;
67 *len += ret;
68 }
69 return 1;
70 }
71
72 /**
73 * Wrapper for the open(2) system call.
74 *
75 * \param path The filename.
76 * \param flags The usual open(2) flags.
77 * \param mode Specifies the permissions to use.
78 *
79 * The mode parameter must be specified when O_CREAT is in the flags, and is
80 * ignored otherwise.
81 *
82 * \return The file descriptor on success, negative on errors.
83 *
84 * \sa open(2).
85 */
86 int osl_open(const char *path, int flags, mode_t mode)
87 {
88 int ret = open(path, flags, mode);
89
90 if (ret >= 0)
91 return ret;
92 return -E_OSL_OPEN;
93 }
94
95 /**
96 * Open a file, write the given buffer and close the file.
97 *
98 * \param filename Full path to the file to open.
99 * \param buf The buffer to write to the file.
100 * \param size The size of \a buf.
101 *
102 * \return Standard.
103 */
104 int write_file(const char *filename, const void *buf, size_t size)
105 {
106 int ret, fd;
107
108 ret = osl_open(filename, O_WRONLY | O_CREAT | O_EXCL, 0644);
109 if (ret < 0)
110 return ret;
111 fd = ret;
112 ret = write_all(fd, buf, &size);
113 if (ret < 0)
114 goto out;
115 ret = 1;
116 out:
117 close(fd);
118 return ret;
119 }
120
121 /**
122 * Open a file and map it into memory.
123 *
124 * \param path Name of the regular file to map.
125 * \param open_mode Either \p O_RDONLY or \p O_RDWR.
126 * \param map On success, the mapping is returned here.
127 * \param size size of the mapping.
128 * \param fd_ptr The file descriptor of the mapping.
129 *
130 * If \a fd_ptr is \p NULL, the file descriptor resulting from the underlying
131 * open call is closed after mmap(). Otherwise the file is kept open and the
132 * file descriptor is returned in \a fd_ptr.
133 *
134 * \return Standard.
135 *
136 * \sa osl_open(), mmap(2).
137 */
138 int mmap_full_file(const char *path, int open_mode, void **map,
139 size_t *size, int *fd_ptr)
140 {
141 int fd, ret, mmap_prot, mmap_flags;
142 struct stat file_status;
143
144 if (open_mode == O_RDONLY) {
145 mmap_prot = PROT_READ;
146 mmap_flags = MAP_PRIVATE;
147 } else {
148 mmap_prot = PROT_READ | PROT_WRITE;
149 mmap_flags = MAP_SHARED;
150 }
151 ret = osl_open(path, open_mode, 0);
152 if (ret < 0)
153 return ret;
154 fd = ret;
155 if (fstat(fd, &file_status) < 0) {
156 ret = -E_OSL_FSTAT;
157 goto out;
158 }
159 *size = file_status.st_size;
160 ret = -E_OSL_EMPTY;
161 DEBUG_LOG("%s: size %zu\n", path, *size);
162 if (!*size)
163 goto out;
164 *map = mmap(NULL, *size, mmap_prot, mmap_flags, fd, 0);
165 if (*map == MAP_FAILED) {
166 *map = NULL;
167 ret = -E_OSL_MMAP;
168 goto out;
169 }
170 ret = 1;
171 out:
172 if (ret < 0 || !fd_ptr)
173 close(fd);
174 else
175 *fd_ptr = fd;
176 return ret;
177 }
178
179 /**
180 * A wrapper for munmap(2).
181 *
182 * \param start The start address of the memory mapping.
183 * \param length The size of the mapping.
184 *
185 * \return Positive on success, \p -E_MUNMAP on errors.
186 *
187 * \sa munmap(2), mmap_full_file().
188 */
189 int osl_munmap(void *start, size_t length)
190 {
191 int err;
192 if (munmap(start, length) >= 0)
193 return 1;
194 err = errno;
195 ERROR_LOG("munmap (%p/%zu) failed: %s\n", start, length,
196 strerror(err));
197 return -E_OSL_MUNMAP;
198 }
199
200 /**
201 * Allocate a sufficiently large string and print into it.
202 *
203 * \param fmt A usual format string.
204 *
205 * Produce output according to \p fmt. No artificial bound on the length of the
206 * resulting string is imposed.
207 *
208 * \return This function either returns a pointer to a string that must be
209 * freed by the caller or \p NULL if memory allocation failed.
210 *
211 * \sa printf(3).
212 */
213 __must_check __printf_1_2 __malloc char *make_message(const char *fmt, ...)
214 {
215 int n;
216 size_t size = 100;
217 char *p = malloc(size);
218
219 if (!p)
220 return NULL;
221 while (1) {
222 char *q;
223 va_list ap;
224 /* Try to print in the allocated space. */
225 va_start(ap, fmt);
226 n = vsnprintf(p, size, fmt, ap);
227 va_end(ap);
228 /* If that worked, return the string. */
229 if (n > -1 && n < size)
230 break;
231 /* Else try again with more space. */
232 if (n > -1) /* glibc 2.1 */
233 size = n + 1; /* precisely what is needed */
234 else /* glibc 2.0 */
235 size *= 2; /* twice the old size */
236 q = realloc(p, size);
237 if (!q) {
238 free(p);
239 return NULL;
240 }
241 p = q;
242 }
243 return p;
244 }
245
246 /**
247 * A wrapper for truncate(2)
248 *
249 * \param path Name of the regular file to truncate
250 * \param size Number of bytes to \b shave \b off
251 *
252 * Truncate the regular file named by \a path by \a size bytes.
253 *
254 * \return Standard.
255 *
256 * \sa truncate(2)
257 */
258 int truncate_file(const char *path, off_t size)
259 {
260 int ret;
261 struct stat statbuf;
262
263 ret = osl_stat(path, &statbuf);
264 if (ret < 0)
265 return ret;
266 ret = -E_OSL_BAD_SIZE;
267 if (statbuf.st_size < size)
268 return ret;
269 if (truncate(path, statbuf.st_size - size) < 0)
270 return -E_OSL_TRUNCATE;
271 return 1;
272 }