/* Remote utility routines for the remote server for GDB.
- Copyright 1986, 1989, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
- 2002
- Free Software Foundation, Inc.
+ Copyright (C) 1986, 1989, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000,
+ 2001, 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
This file is part of GDB.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ Boston, MA 02110-1301, USA. */
#include "server.h"
+#if HAVE_TERMINAL_H
#include "terminal.h"
+#endif
#include <stdio.h>
#include <string.h>
+#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
+#endif
#include <sys/file.h>
+#if HAVE_NETINET_IN_H
#include <netinet/in.h>
+#endif
+#if HAVE_SYS_SOCKET_H
#include <sys/socket.h>
+#endif
+#if HAVE_NETDB_H
#include <netdb.h>
+#endif
+#if HAVE_NETINET_TCP_H
#include <netinet/tcp.h>
+#endif
+#if HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
+#endif
#include <signal.h>
#include <fcntl.h>
#include <sys/time.h>
#include <unistd.h>
+#if HAVE_ARPA_INET_H
+#include <arpa/inet.h>
+#endif
+#include <sys/stat.h>
+#include <errno.h>
+
+#if USE_WIN32API
+#include <winsock.h>
+#endif
+
+#ifndef HAVE_SOCKLEN_T
+typedef int socklen_t;
+#endif
+
+/* A cache entry for a successfully looked-up symbol. */
+struct sym_cache
+{
+ const char *name;
+ CORE_ADDR addr;
+ struct sym_cache *next;
+};
+
+/* The symbol cache. */
+static struct sym_cache *symbol_cache;
+
+/* If this flag has been set, assume cache misses are
+ failures. */
+int all_symbols_looked_up;
int remote_debug = 0;
struct ui_file *gdb_stdlog;
static int remote_desc;
+/* FIXME headerize? */
+extern int using_threads;
+extern int debug_threads;
+
+#ifdef USE_WIN32API
+# define read(fd, buf, len) recv (fd, buf, len, 0)
+# define write(fd, buf, len) send (fd, buf, len, 0)
+#endif
+
/* Open a connection to a remote debugger.
NAME is the filename used for communication. */
void
remote_open (char *name)
{
+#if defined(F_SETFL) && defined (FASYNC)
int save_fcntl_flags;
-
- if (!strchr (name, ':'))
+#endif
+ char *port_str;
+
+ port_str = strchr (name, ':');
+ if (port_str == NULL)
{
- remote_desc = open (name, O_RDWR);
+#ifdef USE_WIN32API
+ error ("Only <host>:<port> is supported on this platform.");
+#else
+ struct stat statbuf;
+
+ if (stat (name, &statbuf) == 0
+ && (S_ISCHR (statbuf.st_mode) || S_ISFIFO (statbuf.st_mode)))
+ remote_desc = open (name, O_RDWR);
+ else
+ {
+ errno = EINVAL;
+ remote_desc = -1;
+ }
+
if (remote_desc < 0)
perror_with_name ("Could not open remote device");
#endif
fprintf (stderr, "Remote debugging using %s\n", name);
+#endif /* USE_WIN32API */
}
else
{
+#ifdef USE_WIN32API
+ static int winsock_initialized;
+#endif
char *port_str;
int port;
struct sockaddr_in sockaddr;
- int tmp;
- struct protoent *protoent;
+ socklen_t tmp;
int tmp_desc;
port_str = strchr (name, ':');
port = atoi (port_str + 1);
- tmp_desc = socket (PF_INET, SOCK_STREAM, 0);
+#ifdef USE_WIN32API
+ if (!winsock_initialized)
+ {
+ WSADATA wsad;
+
+ WSAStartup (MAKEWORD (1, 0), &wsad);
+ winsock_initialized = 1;
+ }
+#endif
+
+ tmp_desc = socket (PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (tmp_desc < 0)
perror_with_name ("Can't open socket");
|| listen (tmp_desc, 1))
perror_with_name ("Can't bind address");
+ fprintf (stderr, "Listening on port %d\n", port);
+ fflush (stderr);
+
tmp = sizeof (sockaddr);
remote_desc = accept (tmp_desc, (struct sockaddr *) &sockaddr, &tmp);
if (remote_desc == -1)
perror_with_name ("Accept failed");
- protoent = getprotobyname ("tcp");
- if (!protoent)
- perror_with_name ("getprotobyname");
-
/* Enable TCP keep alive process. */
tmp = 1;
setsockopt (tmp_desc, SOL_SOCKET, SO_KEEPALIVE, (char *) &tmp, sizeof (tmp));
/* Tell TCP not to delay small packets. This greatly speeds up
interactive response. */
tmp = 1;
- setsockopt (remote_desc, protoent->p_proto, TCP_NODELAY,
+ setsockopt (remote_desc, IPPROTO_TCP, TCP_NODELAY,
(char *) &tmp, sizeof (tmp));
+
+#ifndef USE_WIN32API
close (tmp_desc); /* No longer need this */
signal (SIGPIPE, SIG_IGN); /* If we don't do this, then gdbserver simply
exits when the remote side dies. */
+#else
+ closesocket (tmp_desc); /* No longer need this */
+#endif
/* Convert IP address to string. */
fprintf (stderr, "Remote debugging from host %s\n",
void
remote_close (void)
{
+#ifdef USE_WIN32API
+ closesocket (remote_desc);
+#else
close (remote_desc);
+#endif
}
/* Convert hex digit A to a number. */
return 0;
}
+int
+unhexify (char *bin, const char *hex, int count)
+{
+ int i;
+
+ for (i = 0; i < count; i++)
+ {
+ if (hex[0] == 0 || hex[1] == 0)
+ {
+ /* Hex string is short, or of uneven length.
+ Return the count that has been converted so far. */
+ return i;
+ }
+ *bin++ = fromhex (hex[0]) * 16 + fromhex (hex[1]);
+ hex += 2;
+ }
+ return i;
+}
+
+void
+decode_address (CORE_ADDR *addrp, const char *start, int len)
+{
+ CORE_ADDR addr;
+ char ch;
+ int i;
+
+ addr = 0;
+ for (i = 0; i < len; i++)
+ {
+ ch = start[i];
+ addr = addr << 4;
+ addr = addr | (fromhex (ch) & 0x0f);
+ }
+ *addrp = addr;
+}
+
+const char *
+decode_address_to_semicolon (CORE_ADDR *addrp, const char *start)
+{
+ const char *end;
+
+ end = start;
+ while (*end != '\0' && *end != ';')
+ end++;
+
+ decode_address (addrp, start, end - start);
+
+ if (*end == ';')
+ end++;
+ return end;
+}
+
/* Convert number NIB to a hex digit. */
static int
return 'a' + nib - 10;
}
+int
+hexify (char *hex, const char *bin, int count)
+{
+ int i;
+
+ /* May use a length, or a nul-terminated string as input. */
+ if (count == 0)
+ count = strlen (bin);
+
+ for (i = 0; i < count; i++)
+ {
+ *hex++ = tohex ((*bin >> 4) & 0xf);
+ *hex++ = tohex (*bin++ & 0xf);
+ }
+ *hex = 0;
+ return i;
+}
+
+/* Convert BUFFER, binary data at least LEN bytes long, into escaped
+ binary data in OUT_BUF. Set *OUT_LEN to the length of the data
+ encoded in OUT_BUF, and return the number of bytes in OUT_BUF
+ (which may be more than *OUT_LEN due to escape characters). The
+ total number of bytes in the output buffer will be at most
+ OUT_MAXLEN. */
+
+int
+remote_escape_output (const gdb_byte *buffer, int len,
+ gdb_byte *out_buf, int *out_len,
+ int out_maxlen)
+{
+ int input_index, output_index;
+
+ output_index = 0;
+ for (input_index = 0; input_index < len; input_index++)
+ {
+ gdb_byte b = buffer[input_index];
+
+ if (b == '$' || b == '#' || b == '}' || b == '*')
+ {
+ /* These must be escaped. */
+ if (output_index + 2 > out_maxlen)
+ break;
+ out_buf[output_index++] = '}';
+ out_buf[output_index++] = b ^ 0x20;
+ }
+ else
+ {
+ if (output_index + 1 > out_maxlen)
+ break;
+ out_buf[output_index++] = b;
+ }
+ }
+
+ *out_len = input_index;
+ return output_index;
+}
+
+/* Convert BUFFER, escaped data LEN bytes long, into binary data
+ in OUT_BUF. Return the number of bytes written to OUT_BUF.
+ Raise an error if the total number of bytes exceeds OUT_MAXLEN.
+
+ This function reverses remote_escape_output. It allows more
+ escaped characters than that function does, in particular because
+ '*' must be escaped to avoid the run-length encoding processing
+ in reading packets. */
+
+static int
+remote_unescape_input (const gdb_byte *buffer, int len,
+ gdb_byte *out_buf, int out_maxlen)
+{
+ int input_index, output_index;
+ int escaped;
+
+ output_index = 0;
+ escaped = 0;
+ for (input_index = 0; input_index < len; input_index++)
+ {
+ gdb_byte b = buffer[input_index];
+
+ if (output_index + 1 > out_maxlen)
+ error ("Received too much data from the target.");
+
+ if (escaped)
+ {
+ out_buf[output_index++] = b ^ 0x20;
+ escaped = 0;
+ }
+ else if (b == '}')
+ escaped = 1;
+ else
+ out_buf[output_index++] = b;
+ }
+
+ if (escaped)
+ error ("Unmatched escape character in target response.");
+
+ return output_index;
+}
+
+/* Look for a sequence of characters which can be run-length encoded.
+ If there are any, update *CSUM and *P. Otherwise, output the
+ single character. Return the number of characters consumed. */
+
+static int
+try_rle (char *buf, int remaining, unsigned char *csum, char **p)
+{
+ int n;
+
+ /* Always output the character. */
+ *csum += buf[0];
+ *(*p)++ = buf[0];
+
+ /* Don't go past '~'. */
+ if (remaining > 97)
+ remaining = 97;
+
+ for (n = 1; n < remaining; n++)
+ if (buf[n] != buf[0])
+ break;
+
+ /* N is the index of the first character not the same as buf[0].
+ buf[0] is counted twice, so by decrementing N, we get the number
+ of characters the RLE sequence will replace. */
+ n--;
+
+ if (n < 3)
+ return 1;
+
+ /* Skip the frame characters. The manual says to skip '+' and '-'
+ also, but there's no reason to. Unfortunately these two unusable
+ characters double the encoded length of a four byte zero
+ value. */
+ while (n + 29 == '$' || n + 29 == '#')
+ n--;
+
+ *csum += '*';
+ *(*p)++ = '*';
+ *csum += n + 29;
+ *(*p)++ = n + 29;
+
+ return n + 1;
+}
+
/* Send a packet to the remote machine, with error checking.
- The data of the packet is in BUF. Returns >= 0 on success, -1 otherwise. */
+ The data of the packet is in BUF, and the length of the
+ packet is in CNT. Returns >= 0 on success, -1 otherwise. */
int
-putpkt (char *buf)
+putpkt_binary (char *buf, int cnt)
{
int i;
unsigned char csum = 0;
char *buf2;
char buf3[1];
- int cnt = strlen (buf);
char *p;
buf2 = malloc (PBUFSIZ);
p = buf2;
*p++ = '$';
- for (i = 0; i < cnt; i++)
- {
- csum += buf[i];
- *p++ = buf[i];
- }
+ for (i = 0; i < cnt;)
+ i += try_rle (buf + i, cnt - i, &csum, &p);
+
*p++ = '#';
*p++ = tohex ((csum >> 4) & 0xf);
*p++ = tohex (csum & 0xf);
}
if (remote_debug)
- printf ("putpkt (\"%s\"); [looking for ack]\n", buf2);
+ {
+ fprintf (stderr, "putpkt (\"%s\"); [looking for ack]\n", buf2);
+ fflush (stderr);
+ }
cc = read (remote_desc, buf3, 1);
if (remote_debug)
- printf ("[received '%c' (0x%x)]\n", buf3[0], buf3[0]);
+ {
+ fprintf (stderr, "[received '%c' (0x%x)]\n", buf3[0], buf3[0]);
+ fflush (stderr);
+ }
+
if (cc <= 0)
{
if (cc == 0)
free (buf2);
return -1;
}
+
+ /* Check for an input interrupt while we're here. */
+ if (buf3[0] == '\003')
+ (*the_target->send_signal) (SIGINT);
}
while (buf3[0] != '+');
return 1; /* Success! */
}
+/* Send a packet to the remote machine, with error checking. The data
+ of the packet is in BUF, and the packet should be a NUL-terminated
+ string. Returns >= 0 on success, -1 otherwise. */
+
+int
+putpkt (char *buf)
+{
+ return putpkt_binary (buf, strlen (buf));
+}
+
+#ifndef USE_WIN32API
+
/* Come here when we get an input interrupt from the remote side. This
interrupt should only be active while we are waiting for the child to do
something. About the only thing that should come through is a ^C, which
if (select (remote_desc + 1, &readset, 0, 0, &immediate) > 0)
{
int cc;
- char c;
+ char c = 0;
cc = read (remote_desc, &c, 1);
if (cc != 1 || c != '\003')
{
- fprintf (stderr, "input_interrupt, cc = %d c = %d\n", cc, c);
+ fprintf (stderr, "input_interrupt, count = %d c = %d ('%c')\n",
+ cc, c, c);
return;
}
- kill (inferior_pid, SIGINT);
+ (*the_target->send_signal) (SIGINT);
}
}
+#endif
+
+/* Asynchronous I/O support. SIGIO must be enabled when waiting, in order to
+ accept Control-C from the client, and must be disabled when talking to
+ the client. */
+
+void
+block_async_io (void)
+{
+#ifndef USE_WIN32API
+ sigset_t sigio_set;
+ sigemptyset (&sigio_set);
+ sigaddset (&sigio_set, SIGIO);
+ sigprocmask (SIG_BLOCK, &sigio_set, NULL);
+#endif
+}
+void
+unblock_async_io (void)
+{
+#ifndef USE_WIN32API
+ sigset_t sigio_set;
+ sigemptyset (&sigio_set);
+ sigaddset (&sigio_set, SIGIO);
+ sigprocmask (SIG_UNBLOCK, &sigio_set, NULL);
+#endif
+}
+
+/* Current state of asynchronous I/O. */
+static int async_io_enabled;
+
+/* Enable asynchronous I/O. */
void
enable_async_io (void)
{
+ if (async_io_enabled)
+ return;
+
+#ifndef USE_WIN32API
signal (SIGIO, input_interrupt);
+#endif
+ async_io_enabled = 1;
}
+/* Disable asynchronous I/O. */
void
disable_async_io (void)
{
+ if (!async_io_enabled)
+ return;
+
+#ifndef USE_WIN32API
signal (SIGIO, SIG_IGN);
+#endif
+ async_io_enabled = 0;
}
/* Returns next char from remote GDB. -1 if error. */
static int
readchar (void)
{
- static char buf[BUFSIZ];
+ static unsigned char buf[BUFSIZ];
static int bufcnt = 0;
- static char *bufp;
+ static unsigned char *bufp;
if (bufcnt-- > 0)
- return *bufp++ & 0x7f;
+ return *bufp++;
bufcnt = read (remote_desc, buf, sizeof (buf));
if (c == '$')
break;
if (remote_debug)
- printf ("[getpkt: discarding char '%c']\n", c);
+ {
+ fprintf (stderr, "[getpkt: discarding char '%c']\n", c);
+ fflush (stderr);
+ }
+
if (c < 0)
return -1;
}
}
if (remote_debug)
- printf ("getpkt (\"%s\"); [sending ack] \n", buf);
+ {
+ fprintf (stderr, "getpkt (\"%s\"); [sending ack] \n", buf);
+ fflush (stderr);
+ }
write (remote_desc, "+", 1);
if (remote_debug)
- printf ("[sent ack]\n");
+ {
+ fprintf (stderr, "[sent ack]\n");
+ fflush (stderr);
+ }
+
return bp - buf;
}
void
write_enn (char *buf)
{
+ /* Some day, we should define the meanings of the error codes... */
buf[0] = 'E';
- buf[1] = 'N';
- buf[2] = 'N';
+ buf[1] = '0';
+ buf[2] = '1';
buf[3] = '\0';
}
void
-convert_int_to_ascii (char *from, char *to, int n)
+convert_int_to_ascii (unsigned char *from, char *to, int n)
{
int nib;
- char ch;
+ int ch;
while (n--)
{
ch = *from++;
void
-convert_ascii_to_int (char *from, char *to, int n)
+convert_ascii_to_int (char *from, unsigned char *to, int n)
{
int nib1, nib2;
while (n--)
static char *
outreg (int regno, char *buf)
{
- int regsize = register_size (regno);
-
if ((regno >> 12) != 0)
*buf++ = tohex ((regno >> 12) & 0xf);
if ((regno >> 8) != 0)
*buf++ = tohex ((regno >> 4) & 0xf);
*buf++ = tohex (regno & 0xf);
*buf++ = ':';
- convert_int_to_ascii (register_data (regno), buf, regsize);
- buf += 2 * regsize;
+ collect_register_as_string (regno, buf);
+ buf += 2 * register_size (regno);
*buf++ = ';';
return buf;
}
void
-prepare_resume_reply (char *buf, char status, unsigned char signo)
+new_thread_notify (int id)
+{
+ char own_buf[256];
+
+ /* The `n' response is not yet part of the remote protocol. Do nothing. */
+ if (1)
+ return;
+
+ if (server_waiting == 0)
+ return;
+
+ sprintf (own_buf, "n%x", id);
+ disable_async_io ();
+ putpkt (own_buf);
+ enable_async_io ();
+}
+
+void
+dead_thread_notify (int id)
+{
+ char own_buf[256];
+
+ /* The `x' response is not yet part of the remote protocol. Do nothing. */
+ if (1)
+ return;
+
+ sprintf (own_buf, "x%x", id);
+ disable_async_io ();
+ putpkt (own_buf);
+ enable_async_io ();
+}
+
+void
+prepare_resume_reply (char *buf, char status, unsigned char sig)
{
int nib;
*buf++ = status;
- /* FIXME! Should be converting this signal number (numbered
- according to the signal numbering of the system we are running on)
- to the signal numbers used by the gdb protocol (see enum target_signal
- in gdb/target.h). */
- nib = ((signo & 0xf0) >> 4);
+ nib = ((sig & 0xf0) >> 4);
*buf++ = tohex (nib);
- nib = signo & 0x0f;
+ nib = sig & 0x0f;
*buf++ = tohex (nib);
if (status == 'T')
{
const char **regp = gdbserver_expedite_regs;
+
+ if (the_target->stopped_by_watchpoint != NULL
+ && (*the_target->stopped_by_watchpoint) ())
+ {
+ CORE_ADDR addr;
+ int i;
+
+ strncpy (buf, "watch:", 6);
+ buf += 6;
+
+ addr = (*the_target->stopped_data_address) ();
+
+ /* Convert each byte of the address into two hexadecimal chars.
+ Note that we take sizeof (void *) instead of sizeof (addr);
+ this is to avoid sending a 64-bit address to a 32-bit GDB. */
+ for (i = sizeof (void *) * 2; i > 0; i--)
+ {
+ *buf++ = tohex ((addr >> (i - 1) * 4) & 0xf);
+ }
+ *buf++ = ';';
+ }
+
while (*regp)
{
buf = outreg (find_regno (*regp), buf);
regp ++;
}
- /* If the debugger hasn't used any thread features, don't burden it with
- threads. If we didn't check this, GDB 4.13 and older would choke. */
- if (cont_thread != 0)
+ /* Formerly, if the debugger had not used any thread features we would not
+ burden it with a thread status response. This was for the benefit of
+ GDB 4.13 and older. However, in recent GDB versions the check
+ (``if (cont_thread != 0)'') does not have the desired effect because of
+ sillyness in the way that the remote protocol handles specifying a thread.
+ Since thread support relies on qSymbol support anyway, assume GDB can handle
+ threads. */
+
+ if (using_threads)
{
- if (old_thread_from_wait != thread_from_wait)
+ unsigned int gdb_id_from_wait;
+
+ /* FIXME right place to set this? */
+ thread_from_wait = ((struct inferior_list_entry *)current_inferior)->id;
+ gdb_id_from_wait = thread_to_gdb_id (current_inferior);
+
+ if (debug_threads)
+ fprintf (stderr, "Writing resume reply for %ld\n\n", thread_from_wait);
+ /* This if (1) ought to be unnecessary. But remote_wait in GDB
+ will claim this event belongs to inferior_ptid if we do not
+ specify a thread, and there's no way for gdbserver to know
+ what inferior_ptid is. */
+ if (1 || old_thread_from_wait != thread_from_wait)
{
- sprintf (buf, "thread:%x;", thread_from_wait);
+ general_thread = thread_from_wait;
+ sprintf (buf, "thread:%x;", gdb_id_from_wait);
buf += strlen (buf);
old_thread_from_wait = thread_from_wait;
}
void
decode_M_packet (char *from, CORE_ADDR *mem_addr_ptr, unsigned int *len_ptr,
- char *to)
+ unsigned char *to)
{
int i = 0;
char ch;
convert_ascii_to_int (&from[i++], to, *len_ptr);
}
+
+int
+decode_X_packet (char *from, int packet_len, CORE_ADDR *mem_addr_ptr,
+ unsigned int *len_ptr, unsigned char *to)
+{
+ int i = 0;
+ char ch;
+ *mem_addr_ptr = *len_ptr = 0;
+
+ while ((ch = from[i++]) != ',')
+ {
+ *mem_addr_ptr = *mem_addr_ptr << 4;
+ *mem_addr_ptr |= fromhex (ch) & 0x0f;
+ }
+
+ while ((ch = from[i++]) != ':')
+ {
+ *len_ptr = *len_ptr << 4;
+ *len_ptr |= fromhex (ch) & 0x0f;
+ }
+
+ if (remote_unescape_input ((const gdb_byte *) &from[i], packet_len - i,
+ to, *len_ptr) != *len_ptr)
+ return -1;
+
+ return 0;
+}
+
+/* Ask GDB for the address of NAME, and return it in ADDRP if found.
+ Returns 1 if the symbol is found, 0 if it is not, -1 on error. */
+
+int
+look_up_one_symbol (const char *name, CORE_ADDR *addrp)
+{
+ char own_buf[266], *p, *q;
+ int len;
+ struct sym_cache *sym;
+
+ /* Check the cache first. */
+ for (sym = symbol_cache; sym; sym = sym->next)
+ if (strcmp (name, sym->name) == 0)
+ {
+ *addrp = sym->addr;
+ return 1;
+ }
+
+ /* If we've passed the call to thread_db_look_up_symbols, then
+ anything not in the cache must not exist; we're not interested
+ in any libraries loaded after that point, only in symbols in
+ libpthread.so. It might not be an appropriate time to look
+ up a symbol, e.g. while we're trying to fetch registers. */
+ if (all_symbols_looked_up)
+ return 0;
+
+ /* Send the request. */
+ strcpy (own_buf, "qSymbol:");
+ hexify (own_buf + strlen ("qSymbol:"), name, strlen (name));
+ if (putpkt (own_buf) < 0)
+ return -1;
+
+ /* FIXME: Eventually add buffer overflow checking (to getpkt?) */
+ len = getpkt (own_buf);
+ if (len < 0)
+ return -1;
+
+ if (strncmp (own_buf, "qSymbol:", strlen ("qSymbol:")) != 0)
+ {
+ /* Malformed response. */
+ if (remote_debug)
+ {
+ fprintf (stderr, "Malformed response to qSymbol, ignoring.\n");
+ fflush (stderr);
+ }
+
+ return -1;
+ }
+
+ p = own_buf + strlen ("qSymbol:");
+ q = p;
+ while (*q && *q != ':')
+ q++;
+
+ /* Make sure we found a value for the symbol. */
+ if (p == q || *q == '\0')
+ return 0;
+
+ decode_address (addrp, p, q - p);
+
+ /* Save the symbol in our cache. */
+ sym = malloc (sizeof (*sym));
+ sym->name = strdup (name);
+ sym->addr = *addrp;
+ sym->next = symbol_cache;
+ symbol_cache = sym;
+
+ return 1;
+}
projects / deliverable / binutils-gdb.git / blobdiff