Revision 0b6806b9e45c659d25b87fb5713c920a3081eac8 authored by Steffen Prohaska on 20 August 2013, 06:43:54 UTC, committed by Junio C Hamano on 20 August 2013, 18:10:59 UTC
Checking out 2GB or more through an external filter (see test) fails on Mac OS X 10.8.4 (12E55) for a 64-bit executable with: error: read from external filter cat failed error: cannot feed the input to external filter cat error: cat died of signal 13 error: external filter cat failed 141 error: external filter cat failed The reason is that read() immediately returns with EINVAL when asked to read more than 2GB. According to POSIX [1], if the value of nbyte passed to read() is greater than SSIZE_MAX, the result is implementation-defined. The write function has the same restriction [2]. Since OS X still supports running 32-bit executables, the 32-bit limit (SSIZE_MAX = INT_MAX = 2GB - 1) seems to be also imposed on 64-bit executables under certain conditions. For write, the problem has been addressed earlier [6c642a]. Address the problem for read() and write() differently, by limiting size of IO chunks unconditionally on all platforms in xread() and xwrite(). Large chunks only cause problems, like causing latencies when killing the process, even if OS X was not buggy. Doing IO in reasonably sized smaller chunks should have no negative impact on performance. The compat wrapper clipped_write() introduced earlier [6c642a] is not needed anymore. It will be reverted in a separate commit. The new test catches read and write problems. Note that 'git add' exits with 0 even if it prints filtering errors to stderr. The test, therefore, checks stderr. 'git add' should probably be changed (sometime in another commit) to exit with nonzero if filtering fails. The test could then be changed to use test_must_fail. Thanks to the following people for suggestions and testing: Johannes Sixt <j6t@kdbg.org> John Keeping <john@keeping.me.uk> Jonathan Nieder <jrnieder@gmail.com> Kyle J. McKay <mackyle@gmail.com> Linus Torvalds <torvalds@linux-foundation.org> Torsten Bögershausen <tboegi@web.de> [1] http://pubs.opengroup.org/onlinepubs/009695399/functions/read.html [2] http://pubs.opengroup.org/onlinepubs/009695399/functions/write.html [6c642a] commit 6c642a878688adf46b226903858b53e2d31ac5c3 compate/clipped-write.c: large write(2) fails on Mac OS X/XNU Signed-off-by: Steffen Prohaska <prohaska@zib.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 4d06473
shell.c
#include "cache.h"
#include "quote.h"
#include "exec_cmd.h"
#include "strbuf.h"
#include "run-command.h"
#define COMMAND_DIR "git-shell-commands"
#define HELP_COMMAND COMMAND_DIR "/help"
#define NOLOGIN_COMMAND COMMAND_DIR "/no-interactive-login"
static int do_generic_cmd(const char *me, char *arg)
{
const char *my_argv[4];
setup_path();
if (!arg || !(arg = sq_dequote(arg)))
die("bad argument");
if (prefixcmp(me, "git-"))
die("bad command");
my_argv[0] = me + 4;
my_argv[1] = arg;
my_argv[2] = NULL;
return execv_git_cmd(my_argv);
}
static int do_cvs_cmd(const char *me, char *arg)
{
const char *cvsserver_argv[3] = {
"cvsserver", "server", NULL
};
if (!arg || strcmp(arg, "server"))
die("git-cvsserver only handles server: %s", arg);
setup_path();
return execv_git_cmd(cvsserver_argv);
}
static int is_valid_cmd_name(const char *cmd)
{
/* Test command contains no . or / characters */
return cmd[strcspn(cmd, "./")] == '\0';
}
static char *make_cmd(const char *prog)
{
char *prefix = xmalloc((strlen(prog) + strlen(COMMAND_DIR) + 2));
strcpy(prefix, COMMAND_DIR);
strcat(prefix, "/");
strcat(prefix, prog);
return prefix;
}
static void cd_to_homedir(void)
{
const char *home = getenv("HOME");
if (!home)
die("could not determine user's home directory; HOME is unset");
if (chdir(home) == -1)
die("could not chdir to user's home directory");
}
static void run_shell(void)
{
int done = 0;
static const char *help_argv[] = { HELP_COMMAND, NULL };
if (!access(NOLOGIN_COMMAND, F_OK)) {
/* Interactive login disabled. */
const char *argv[] = { NOLOGIN_COMMAND, NULL };
int status;
status = run_command_v_opt(argv, 0);
if (status < 0)
exit(127);
exit(status);
}
/* Print help if enabled */
run_command_v_opt(help_argv, RUN_SILENT_EXEC_FAILURE);
do {
struct strbuf line = STRBUF_INIT;
const char *prog;
char *full_cmd;
char *rawargs;
char *split_args;
const char **argv;
int code;
int count;
fprintf(stderr, "git> ");
if (strbuf_getline(&line, stdin, '\n') == EOF) {
fprintf(stderr, "\n");
strbuf_release(&line);
break;
}
strbuf_trim(&line);
rawargs = strbuf_detach(&line, NULL);
split_args = xstrdup(rawargs);
count = split_cmdline(split_args, &argv);
if (count < 0) {
fprintf(stderr, "invalid command format '%s': %s\n", rawargs,
split_cmdline_strerror(count));
free(split_args);
free(rawargs);
continue;
}
prog = argv[0];
if (!strcmp(prog, "")) {
} else if (!strcmp(prog, "quit") || !strcmp(prog, "logout") ||
!strcmp(prog, "exit") || !strcmp(prog, "bye")) {
done = 1;
} else if (is_valid_cmd_name(prog)) {
full_cmd = make_cmd(prog);
argv[0] = full_cmd;
code = run_command_v_opt(argv, RUN_SILENT_EXEC_FAILURE);
if (code == -1 && errno == ENOENT) {
fprintf(stderr, "unrecognized command '%s'\n", prog);
}
free(full_cmd);
} else {
fprintf(stderr, "invalid command format '%s'\n", prog);
}
free(argv);
free(rawargs);
} while (!done);
}
static struct commands {
const char *name;
int (*exec)(const char *me, char *arg);
} cmd_list[] = {
{ "git-receive-pack", do_generic_cmd },
{ "git-upload-pack", do_generic_cmd },
{ "git-upload-archive", do_generic_cmd },
{ "cvs", do_cvs_cmd },
{ NULL },
};
int main(int argc, char **argv)
{
char *prog;
const char **user_argv;
struct commands *cmd;
int count;
git_setup_gettext();
git_extract_argv0_path(argv[0]);
/*
* Always open file descriptors 0/1/2 to avoid clobbering files
* in die(). It also avoids messing up when the pipes are dup'ed
* onto stdin/stdout/stderr in the child processes we spawn.
*/
sanitize_stdfds();
/*
* Special hack to pretend to be a CVS server
*/
if (argc == 2 && !strcmp(argv[1], "cvs server")) {
argv--;
} else if (argc == 1) {
/* Allow the user to run an interactive shell */
cd_to_homedir();
if (access(COMMAND_DIR, R_OK | X_OK) == -1) {
die("Interactive git shell is not enabled.\n"
"hint: ~/" COMMAND_DIR " should exist "
"and have read and execute access.");
}
run_shell();
exit(0);
} else if (argc != 3 || strcmp(argv[1], "-c")) {
/*
* We do not accept any other modes except "-c" followed by
* "cmd arg", where "cmd" is a very limited subset of git
* commands or a command in the COMMAND_DIR
*/
die("Run with no arguments or with -c cmd");
}
prog = xstrdup(argv[2]);
if (!strncmp(prog, "git", 3) && isspace(prog[3]))
/* Accept "git foo" as if the caller said "git-foo". */
prog[3] = '-';
for (cmd = cmd_list ; cmd->name ; cmd++) {
int len = strlen(cmd->name);
char *arg;
if (strncmp(cmd->name, prog, len))
continue;
arg = NULL;
switch (prog[len]) {
case '\0':
arg = NULL;
break;
case ' ':
arg = prog + len + 1;
break;
default:
continue;
}
exit(cmd->exec(cmd->name, arg));
}
cd_to_homedir();
count = split_cmdline(prog, &user_argv);
if (count >= 0) {
if (is_valid_cmd_name(user_argv[0])) {
prog = make_cmd(user_argv[0]);
user_argv[0] = prog;
execv(user_argv[0], (char *const *) user_argv);
}
free(prog);
free(user_argv);
die("unrecognized command '%s'", argv[2]);
} else {
free(prog);
die("invalid command format '%s': %s", argv[2],
split_cmdline_strerror(count));
}
}
![swh spinner](/static/img/swh-spinner.gif)
Computing file changes ...