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There are some places in passt/pasta which #include <assert.h> and make various assertions. If we hit these something has already gone wrong, but they're there so that we a useful message instead of cryptic misbehaviour if assumptions we thought were correct turn out not to be. Except.. the glibc implementation of assert() uses syscalls that aren't in our seccomp filter, so we'll get a SIGSYS before it actually prints the message. Work around this by adding our own ASSERT() implementation using our existing err() function to log the message, and an abort(). The abort() probably also won't work exactly right with seccomp, but once we've printed the message, dying with a SIGSYS works just as well as dying with a SIGABRT. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
116 lines
2.7 KiB
C
116 lines
2.7 KiB
C
// SPDX-License-Identifier: AGPL-3.0-or-later
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/* PASST - Plug A Simple Socket Transport
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* for qemu/UNIX domain socket mode
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*
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* PASTA - Pack A Subtle Tap Abstraction
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* for network namespace/tap device mode
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*
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* lineread.c - Allocation free line-by-line buffered file input
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*
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* Copyright Red Hat
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* Author: David Gibson <david@gibson.dropbear.id.au>
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*/
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#include <stddef.h>
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#include <fcntl.h>
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#include <string.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include "lineread.h"
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#include "util.h"
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/**
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* lineread_init() - Prepare for line by line file reading without allocation
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* @lr: Line reader state structure to initialize
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* @fd: File descriptor to read lines from
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*/
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void lineread_init(struct lineread *lr, int fd)
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{
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lr->fd = fd;
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lr->next_line = lr->count = 0;
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}
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/**
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* peek_line() - Find and NULL-terminate next line in buffer
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* @lr: Line reader state structure
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* @eof: Caller indicates end-of-file was already found by read()
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*
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* Return: length of line in bytes, -1 if no line was found
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*/
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static int peek_line(struct lineread *lr, bool eof)
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{
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char *nl;
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/* Sanity checks (which also document invariants) */
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ASSERT(lr->count >= 0);
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ASSERT(lr->next_line >= 0);
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ASSERT(lr->next_line + lr->count >= lr->next_line);
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ASSERT(lr->next_line + lr->count <= LINEREAD_BUFFER_SIZE);
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nl = memchr(lr->buf + lr->next_line, '\n', lr->count);
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if (nl) {
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*nl = '\0';
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return nl - lr->buf - lr->next_line + 1;
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}
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if (eof) {
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lr->buf[lr->next_line + lr->count] = '\0';
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/* No trailing newline, so treat all remaining bytes
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* as the last line
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*/
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return lr->count;
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}
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return -1;
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}
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/**
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* lineread_get() - Read a single line from file (no allocation)
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* @lr: Line reader state structure
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* @line: Place a pointer to the next line in this variable
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*
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* Return: Length of line read on success, 0 on EOF, negative on error
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*/
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int lineread_get(struct lineread *lr, char **line)
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{
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bool eof = false;
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int line_len;
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while ((line_len = peek_line(lr, eof)) < 0) {
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int rc;
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if ((lr->next_line + lr->count) == LINEREAD_BUFFER_SIZE) {
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/* No space at end */
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if (lr->next_line == 0) {
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/* Buffer is full, which means we've
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* hit a line too long for us to
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* process. FIXME: report error
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* better
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*/
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return -1;
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}
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memmove(lr->buf, lr->buf + lr->next_line, lr->count);
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lr->next_line = 0;
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}
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/* Read more data into the end of buffer */
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rc = read(lr->fd, lr->buf + lr->next_line + lr->count,
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LINEREAD_BUFFER_SIZE - lr->next_line - lr->count);
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if (rc < 0)
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return rc;
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if (rc == 0)
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eof = true;
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else
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lr->count += rc;
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}
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*line = lr->buf + lr->next_line;
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lr->next_line += line_len;
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lr->count -= line_len;
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return line_len;
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}
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