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sys/vfs: add vfs_readline()

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This commit is contained in:
Benjamin Valentin 2024-04-30 17:41:39 +02:00
parent ee8569f7da
commit 469c919969
2 changed files with 71 additions and 5 deletions
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14
sys/include/vfs.h
View File

@ -841,6 +841,20 @@ int vfs_open(const char *name, int flags, mode_t mode);
*/
ssize_t vfs_read(int fd, void *dest, size_t count);
/**
* @brief Read a line from an open text file
*
* Reads from a file until a `\r` or `\n` character is found.
*
* @param[in] fd fd number obtained from vfs_open
* @param[out] dest destination buffer to hold the line
* @param[in] count maximum number of characters to read
*
* @return number of bytes read on success
* @return <0 on error
*/
ssize_t vfs_readline(int fd, char *dest, size_t count);
/**
* @brief Write bytes to an open file
*

62
sys/vfs/vfs.c
View File

@ -317,28 +317,80 @@ int vfs_open(const char *name, int flags, mode_t mode)
return fd;
}
ssize_t vfs_read(int fd, void *dest, size_t count)
static inline int _prep_read(int fd, const void *dest, vfs_file_t **filp)
{
DEBUG("vfs_read: %d, %p, %" PRIuSIZE "\n", fd, dest, count);
if (dest == NULL) {
return -EFAULT;
}
int res = _fd_is_valid(fd);
if (res < 0) {
return res;
}
vfs_file_t *filp = &_vfs_open_files[fd];
if (((filp->flags & O_ACCMODE) != O_RDONLY) & ((filp->flags & O_ACCMODE) != O_RDWR)) {
*filp = &_vfs_open_files[fd];
if ((((*filp)->flags & O_ACCMODE) != O_RDONLY) &&
(((*filp)->flags & O_ACCMODE) != O_RDWR)) {
/* File not open for reading */
return -EBADF;
}
if (filp->f_op->read == NULL) {
if ((*filp)->f_op->read == NULL) {
/* driver does not implement read() */
return -EINVAL;
}
return 0;
}
ssize_t vfs_read(int fd, void *dest, size_t count)
{
DEBUG("vfs_read: %d, %p, %" PRIuSIZE "\n", fd, dest, count);
vfs_file_t *filp = NULL;
int res = _prep_read(fd, dest, &filp);
if (res) {
DEBUG("vfs_read: can't open file - %d\n", res);
return res;
}
return filp->f_op->read(filp, dest, count);
}
ssize_t vfs_readline(int fd, char *dst, size_t len_max)
{
DEBUG("vfs_readline: %d, %p, %" PRIuSIZE "\n", fd, (void *)dst, len_max);
vfs_file_t *filp = NULL;
int res = _prep_read(fd, dst, &filp);
if (res) {
DEBUG("vfs_readline: can't open file - %d\n", res);
return res;
}
const char *start = dst;
while (len_max) {
int res = filp->f_op->read(filp, dst, 1);
if (res < 0) {
break;
}
if (*dst == '\r' || *dst == '\n' || res == 0) {
*dst = 0;
++dst;
break;
} else {
--len_max;
++dst;
}
}
if (len_max == 0) {
return -E2BIG;
}
return dst - start;
}
ssize_t vfs_write(int fd, const void *src, size_t count)
{
DEBUG_NOT_STDOUT(fd, "vfs_write: %d, %p, %" PRIuSIZE "\n", fd, src, count);