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Diffstat (limited to 'gdbserver/hostio.cc')
| -rw-r--r-- | gdbserver/hostio.cc | 620 |
1 files changed, 620 insertions, 0 deletions
diff --git a/gdbserver/hostio.cc b/gdbserver/hostio.cc new file mode 100644 index 0000000..8af4fbf --- /dev/null +++ b/gdbserver/hostio.cc @@ -0,0 +1,620 @@ +/* Host file transfer support for gdbserver. + Copyright (C) 2007-2020 Free Software Foundation, Inc. + + Contributed by CodeSourcery. + + This file is part of GDB. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. */ + +#include "server.h" +#include "gdb/fileio.h" +#include "hostio.h" + +#include <fcntl.h> +#include <limits.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include "gdbsupport/fileio.h" + +struct fd_list +{ + int fd; + struct fd_list *next; +}; + +static struct fd_list *open_fds; + +static int +safe_fromhex (char a, int *nibble) +{ + if (a >= '0' && a <= '9') + *nibble = a - '0'; + else if (a >= 'a' && a <= 'f') + *nibble = a - 'a' + 10; + else if (a >= 'A' && a <= 'F') + *nibble = a - 'A' + 10; + else + return -1; + + return 0; +} + +/* Filenames are hex encoded, so the maximum we can handle is half the + packet buffer size. Cap to PATH_MAX, if it is shorter. */ +#if !defined (PATH_MAX) || (PATH_MAX > (PBUFSIZ / 2 + 1)) +# define HOSTIO_PATH_MAX (PBUFSIZ / 2 + 1) +#else +# define HOSTIO_PATH_MAX PATH_MAX +#endif + +static int +require_filename (char **pp, char *filename) +{ + int count; + char *p; + + p = *pp; + count = 0; + + while (*p && *p != ',') + { + int nib1, nib2; + + /* Don't allow overflow. */ + if (count >= HOSTIO_PATH_MAX - 1) + return -1; + + if (safe_fromhex (p[0], &nib1) + || safe_fromhex (p[1], &nib2)) + return -1; + + filename[count++] = nib1 * 16 + nib2; + p += 2; + } + + filename[count] = '\0'; + *pp = p; + return 0; +} + +static int +require_int (char **pp, int *value) +{ + char *p; + int count, firstdigit; + + p = *pp; + *value = 0; + count = 0; + firstdigit = -1; + + while (*p && *p != ',') + { + int nib; + + if (safe_fromhex (p[0], &nib)) + return -1; + + if (firstdigit == -1) + firstdigit = nib; + + /* Don't allow overflow. */ + if (count >= 8 || (count == 7 && firstdigit >= 0x8)) + return -1; + + *value = *value * 16 + nib; + p++; + count++; + } + + *pp = p; + return 0; +} + +static int +require_data (char *p, int p_len, char **data, int *data_len) +{ + int input_index, output_index, escaped; + + *data = (char *) xmalloc (p_len); + + output_index = 0; + escaped = 0; + for (input_index = 0; input_index < p_len; input_index++) + { + char b = p[input_index]; + + if (escaped) + { + (*data)[output_index++] = b ^ 0x20; + escaped = 0; + } + else if (b == '}') + escaped = 1; + else + (*data)[output_index++] = b; + } + + if (escaped) + { + free (*data); + return -1; + } + + *data_len = output_index; + return 0; +} + +static int +require_comma (char **pp) +{ + if (**pp == ',') + { + (*pp)++; + return 0; + } + else + return -1; +} + +static int +require_end (char *p) +{ + if (*p == '\0') + return 0; + else + return -1; +} + +static int +require_valid_fd (int fd) +{ + struct fd_list *fd_ptr; + + for (fd_ptr = open_fds; fd_ptr != NULL; fd_ptr = fd_ptr->next) + if (fd_ptr->fd == fd) + return 0; + + return -1; +} + +/* Fill in own_buf with the last hostio error packet, however it + suitable for the target. */ +static void +hostio_error (char *own_buf) +{ + the_target->hostio_last_error (own_buf); +} + +static void +hostio_packet_error (char *own_buf) +{ + sprintf (own_buf, "F-1,%x", FILEIO_EINVAL); +} + +static void +hostio_reply (char *own_buf, int result) +{ + sprintf (own_buf, "F%x", result); +} + +static int +hostio_reply_with_data (char *own_buf, char *buffer, int len, + int *new_packet_len) +{ + int input_index, output_index, out_maxlen; + + sprintf (own_buf, "F%x;", len); + output_index = strlen (own_buf); + + out_maxlen = PBUFSIZ; + + for (input_index = 0; input_index < len; input_index++) + { + char b = buffer[input_index]; + + if (b == '$' || b == '#' || b == '}' || b == '*') + { + /* These must be escaped. */ + if (output_index + 2 > out_maxlen) + break; + own_buf[output_index++] = '}'; + own_buf[output_index++] = b ^ 0x20; + } + else + { + if (output_index + 1 > out_maxlen) + break; + own_buf[output_index++] = b; + } + } + + *new_packet_len = output_index; + return input_index; +} + +/* Process ID of inferior whose filesystem hostio functions + that take FILENAME arguments will use. Zero means to use + our own filesystem. */ + +static int hostio_fs_pid; + +/* See hostio.h. */ + +void +hostio_handle_new_gdb_connection (void) +{ + hostio_fs_pid = 0; +} + +/* Handle a "vFile:setfs:" packet. */ + +static void +handle_setfs (char *own_buf) +{ + char *p; + int pid; + + /* If the target doesn't have any of the in-filesystem-of methods + then there's no point in GDB sending "vFile:setfs:" packets. We + reply with an empty packet (i.e. we pretend we don't understand + "vFile:setfs:") and that should stop GDB sending any more. */ + if (the_target->multifs_open == NULL + && the_target->multifs_unlink == NULL + && the_target->multifs_readlink == NULL) + { + own_buf[0] = '\0'; + return; + } + + p = own_buf + strlen ("vFile:setfs:"); + + if (require_int (&p, &pid) + || pid < 0 + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + hostio_fs_pid = pid; + + hostio_reply (own_buf, 0); +} + +static void +handle_open (char *own_buf) +{ + char filename[HOSTIO_PATH_MAX]; + char *p; + int fileio_flags, fileio_mode, flags, fd; + mode_t mode; + struct fd_list *new_fd; + + p = own_buf + strlen ("vFile:open:"); + + if (require_filename (&p, filename) + || require_comma (&p) + || require_int (&p, &fileio_flags) + || require_comma (&p) + || require_int (&p, &fileio_mode) + || require_end (p) + || fileio_to_host_openflags (fileio_flags, &flags) + || fileio_to_host_mode (fileio_mode, &mode)) + { + hostio_packet_error (own_buf); + return; + } + + /* We do not need to convert MODE, since the fileio protocol + uses the standard values. */ + if (hostio_fs_pid != 0 && the_target->multifs_open != NULL) + fd = the_target->multifs_open (hostio_fs_pid, filename, + flags, mode); + else + fd = open (filename, flags, mode); + + if (fd == -1) + { + hostio_error (own_buf); + return; + } + + /* Record the new file descriptor. */ + new_fd = XNEW (struct fd_list); + new_fd->fd = fd; + new_fd->next = open_fds; + open_fds = new_fd; + + hostio_reply (own_buf, fd); +} + +static void +handle_pread (char *own_buf, int *new_packet_len) +{ + int fd, ret, len, offset, bytes_sent; + char *p, *data; + static int max_reply_size = -1; + + p = own_buf + strlen ("vFile:pread:"); + + if (require_int (&p, &fd) + || require_comma (&p) + || require_valid_fd (fd) + || require_int (&p, &len) + || require_comma (&p) + || require_int (&p, &offset) + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + /* Do not attempt to read more than the maximum number of bytes + hostio_reply_with_data can fit in a packet. We may still read + too much because of escaping, but this is handled below. */ + if (max_reply_size == -1) + { + sprintf (own_buf, "F%x;", PBUFSIZ); + max_reply_size = PBUFSIZ - strlen (own_buf); + } + if (len > max_reply_size) + len = max_reply_size; + + data = (char *) xmalloc (len); +#ifdef HAVE_PREAD + ret = pread (fd, data, len, offset); +#else + ret = -1; +#endif + /* If we have no pread or it failed for this file, use lseek/read. */ + if (ret == -1) + { + ret = lseek (fd, offset, SEEK_SET); + if (ret != -1) + ret = read (fd, data, len); + } + + if (ret == -1) + { + hostio_error (own_buf); + free (data); + return; + } + + bytes_sent = hostio_reply_with_data (own_buf, data, ret, new_packet_len); + + /* If we were using read, and the data did not all fit in the reply, + we would have to back up using lseek here. With pread it does + not matter. But we still have a problem; the return value in the + packet might be wrong, so we must fix it. This time it will + definitely fit. */ + if (bytes_sent < ret) + bytes_sent = hostio_reply_with_data (own_buf, data, bytes_sent, + new_packet_len); + + free (data); +} + +static void +handle_pwrite (char *own_buf, int packet_len) +{ + int fd, ret, len, offset; + char *p, *data; + + p = own_buf + strlen ("vFile:pwrite:"); + + if (require_int (&p, &fd) + || require_comma (&p) + || require_valid_fd (fd) + || require_int (&p, &offset) + || require_comma (&p) + || require_data (p, packet_len - (p - own_buf), &data, &len)) + { + hostio_packet_error (own_buf); + return; + } + +#ifdef HAVE_PWRITE + ret = pwrite (fd, data, len, offset); +#else + ret = -1; +#endif + /* If we have no pwrite or it failed for this file, use lseek/write. */ + if (ret == -1) + { + ret = lseek (fd, offset, SEEK_SET); + if (ret != -1) + ret = write (fd, data, len); + } + + if (ret == -1) + { + hostio_error (own_buf); + free (data); + return; + } + + hostio_reply (own_buf, ret); + free (data); +} + +static void +handle_fstat (char *own_buf, int *new_packet_len) +{ + int fd, bytes_sent; + char *p; + struct stat st; + struct fio_stat fst; + + p = own_buf + strlen ("vFile:fstat:"); + + if (require_int (&p, &fd) + || require_valid_fd (fd) + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + if (fstat (fd, &st) == -1) + { + hostio_error (own_buf); + return; + } + + host_to_fileio_stat (&st, &fst); + + bytes_sent = hostio_reply_with_data (own_buf, + (char *) &fst, sizeof (fst), + new_packet_len); + + /* If the response does not fit into a single packet, do not attempt + to return a partial response, but simply fail. */ + if (bytes_sent < sizeof (fst)) + write_enn (own_buf); +} + +static void +handle_close (char *own_buf) +{ + int fd, ret; + char *p; + struct fd_list **open_fd_p, *old_fd; + + p = own_buf + strlen ("vFile:close:"); + + if (require_int (&p, &fd) + || require_valid_fd (fd) + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + ret = close (fd); + + if (ret == -1) + { + hostio_error (own_buf); + return; + } + + open_fd_p = &open_fds; + /* We know that fd is in the list, thanks to require_valid_fd. */ + while ((*open_fd_p)->fd != fd) + open_fd_p = &(*open_fd_p)->next; + + old_fd = *open_fd_p; + *open_fd_p = (*open_fd_p)->next; + free (old_fd); + + hostio_reply (own_buf, ret); +} + +static void +handle_unlink (char *own_buf) +{ + char filename[HOSTIO_PATH_MAX]; + char *p; + int ret; + + p = own_buf + strlen ("vFile:unlink:"); + + if (require_filename (&p, filename) + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + if (hostio_fs_pid != 0 && the_target->multifs_unlink != NULL) + ret = the_target->multifs_unlink (hostio_fs_pid, filename); + else + ret = unlink (filename); + + if (ret == -1) + { + hostio_error (own_buf); + return; + } + + hostio_reply (own_buf, ret); +} + +static void +handle_readlink (char *own_buf, int *new_packet_len) +{ + char filename[HOSTIO_PATH_MAX], linkname[HOSTIO_PATH_MAX]; + char *p; + int ret, bytes_sent; + + p = own_buf + strlen ("vFile:readlink:"); + + if (require_filename (&p, filename) + || require_end (p)) + { + hostio_packet_error (own_buf); + return; + } + + if (hostio_fs_pid != 0 && the_target->multifs_readlink != NULL) + ret = the_target->multifs_readlink (hostio_fs_pid, filename, + linkname, + sizeof (linkname) - 1); + else + ret = readlink (filename, linkname, sizeof (linkname) - 1); + + if (ret == -1) + { + hostio_error (own_buf); + return; + } + + bytes_sent = hostio_reply_with_data (own_buf, linkname, ret, new_packet_len); + + /* If the response does not fit into a single packet, do not attempt + to return a partial response, but simply fail. */ + if (bytes_sent < ret) + sprintf (own_buf, "F-1,%x", FILEIO_ENAMETOOLONG); +} + +/* Handle all the 'F' file transfer packets. */ + +int +handle_vFile (char *own_buf, int packet_len, int *new_packet_len) +{ + if (startswith (own_buf, "vFile:open:")) + handle_open (own_buf); + else if (startswith (own_buf, "vFile:pread:")) + handle_pread (own_buf, new_packet_len); + else if (startswith (own_buf, "vFile:pwrite:")) + handle_pwrite (own_buf, packet_len); + else if (startswith (own_buf, "vFile:fstat:")) + handle_fstat (own_buf, new_packet_len); + else if (startswith (own_buf, "vFile:close:")) + handle_close (own_buf); + else if (startswith (own_buf, "vFile:unlink:")) + handle_unlink (own_buf); + else if (startswith (own_buf, "vFile:readlink:")) + handle_readlink (own_buf, new_packet_len); + else if (startswith (own_buf, "vFile:setfs:")) + handle_setfs (own_buf); + else + return 0; + + return 1; +} |