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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202/* SPDX-License-Identifier: GPL-2.0 *//* * Lightweight buffered reading library. * * Copyright 2019 Google LLC. */#ifndef __API_IO__#define __API_IO__
#include <errno.h>#include <poll.h>#include <stdlib.h>#include <string.h>#include <unistd.h>#include <linux/types.h>
struct io { /* File descriptor being read/ */ int fd; /* Size of the read buffer. */ unsigned int buf_len; /* Pointer to storage for buffering read. */ char *buf; /* End of the storage. */ char *end; /* Currently accessed data pointer. */ char *data; /* Read timeout, 0 implies no timeout. */ int timeout_ms; /* Set true on when the end of file on read error. */ bool eof;};
static inline void io__init(struct io *io, int fd, char *buf, unsigned int buf_len){ io->fd = fd; io->buf_len = buf_len; io->buf = buf; io->end = buf; io->data = buf; io->timeout_ms = 0; io->eof = false;}
/* Read from fd filling the buffer. Called when io->data == io->end. */static inline int io__fill_buffer(struct io *io){ ssize_t n;
if (io->eof) return -1;
if (io->timeout_ms != 0) { struct pollfd pfds[] = { { .fd = io->fd, .events = POLLIN, }, };
n = poll(pfds, 1, io->timeout_ms); if (n == 0) errno = ETIMEDOUT; if (n > 0 && !(pfds[0].revents & POLLIN)) { errno = EIO; n = -1; } if (n <= 0) { io->eof = true; return -1; } } n = read(io->fd, io->buf, io->buf_len);
if (n <= 0) { io->eof = true; return -1; } io->data = &io->buf[0]; io->end = &io->buf[n]; return 0;}
/* Reads one character from the "io" file with similar semantics to fgetc. */static inline int io__get_char(struct io *io){ if (io->data == io->end) { int ret = io__fill_buffer(io);
if (ret) return ret; } return *io->data++;}
/* Read a hexadecimal value with no 0x prefix into the out argument hex. If the * first character isn't hexadecimal returns -2, io->eof returns -1, otherwise * returns the character after the hexadecimal value which may be -1 for eof. * If the read value is larger than a u64 the high-order bits will be dropped. */static inline int io__get_hex(struct io *io, __u64 *hex){ bool first_read = true;
*hex = 0; while (true) { int ch = io__get_char(io);
if (ch < 0) return ch; if (ch >= '0' && ch <= '9') *hex = (*hex << 4) | (ch - '0'); else if (ch >= 'a' && ch <= 'f') *hex = (*hex << 4) | (ch - 'a' + 10); else if (ch >= 'A' && ch <= 'F') *hex = (*hex << 4) | (ch - 'A' + 10); else if (first_read) return -2; else return ch; first_read = false; }}
/* Read a positive decimal value with out argument dec. If the first character * isn't a decimal returns -2, io->eof returns -1, otherwise returns the * character after the decimal value which may be -1 for eof. If the read value * is larger than a u64 the high-order bits will be dropped. */static inline int io__get_dec(struct io *io, __u64 *dec){ bool first_read = true;
*dec = 0; while (true) { int ch = io__get_char(io);
if (ch < 0) return ch; if (ch >= '0' && ch <= '9') *dec = (*dec * 10) + ch - '0'; else if (first_read) return -2; else return ch; first_read = false; }}
/* Read up to and including the first delim. */static inline ssize_t io__getdelim(struct io *io, char **line_out, size_t *line_len_out, int delim){ char buf[128]; int buf_pos = 0; char *line = NULL, *temp; size_t line_len = 0; int ch = 0;
/* TODO: reuse previously allocated memory. */ free(*line_out); while (ch != delim) { ch = io__get_char(io);
if (ch < 0) break;
if (buf_pos == sizeof(buf)) { temp = realloc(line, line_len + sizeof(buf)); if (!temp) goto err_out; line = temp; memcpy(&line[line_len], buf, sizeof(buf)); line_len += sizeof(buf); buf_pos = 0; } buf[buf_pos++] = (char)ch; } temp = realloc(line, line_len + buf_pos + 1); if (!temp) goto err_out; line = temp; memcpy(&line[line_len], buf, buf_pos); line[line_len + buf_pos] = '\0'; line_len += buf_pos; *line_out = line; *line_len_out = line_len; return line_len;err_out: free(line); *line_out = NULL; *line_len_out = 0; return -ENOMEM;}
static inline ssize_t io__getline(struct io *io, char **line_out, size_t *line_len_out){ return io__getdelim(io, line_out, line_len_out, /*delim=*/'\n');}
#endif /* __API_IO__ */