From 7f3ecebfcda9b32252a4791dc716c1e3d88c9f70 Mon Sep 17 00:00:00 2001 From: Ilari Liusvaara Date: Tue, 12 Oct 2010 19:39:43 +0300 Subject: [PATCH] git-remote-ext This remote helper invokes external command and passes raw smart transport stream through it. This is useful for instance for invoking ssh with one-off odd options, connecting to git services in unix domain sockets, in abstract namespace, using TLS or other secure protocols, etc... Signed-off-by: Ilari Liusvaara Signed-off-by: Junio C Hamano --- .gitignore | 1 + Documentation/git-remote-ext.txt | 125 ++++++++++++++++ Makefile | 1 + builtin.h | 1 + builtin/remote-ext.c | 248 +++++++++++++++++++++++++++++++ git.c | 1 + 6 files changed, 377 insertions(+) create mode 100644 Documentation/git-remote-ext.txt create mode 100644 builtin/remote-ext.c diff --git a/.gitignore b/.gitignore index 89f37f42f7..87b833c9d8 100644 --- a/.gitignore +++ b/.gitignore @@ -113,6 +113,7 @@ /git-remote-ftp /git-remote-ftps /git-remote-fd +/git-remote-ext /git-remote-testgit /git-repack /git-replace diff --git a/Documentation/git-remote-ext.txt b/Documentation/git-remote-ext.txt new file mode 100644 index 0000000000..8fb260b54b --- /dev/null +++ b/Documentation/git-remote-ext.txt @@ -0,0 +1,125 @@ +git-remote-ext(1) +================= + +NAME +---- +git-remote-ext - Bridge smart transport to external command. + +SYNOPSIS +-------- +git remote add nick "ext::[ ...]" + +DESCRIPTION +----------- +This remote helper uses the specified 'program' to connect +to a remote git server. + +Data written to stdin of this specified 'program' is assumed +to be sent to git:// server, git-upload-pack, git-receive-pack +or git-upload-archive (depending on situation), and data read +from stdout of this program is assumed to be received from +the same service. + +Command and arguments are separated by unescaped space. + +The following sequences have a special meaning: + +'% ':: + Literal space in command or argument. + +'%%':: + Literal percent sign. + +'%s':: + Replaced with name (receive-pack, upload-pack, or + upload-archive) of the service git wants to invoke. + +'%S':: + Replaced with long name (git-receive-pack, + git-upload-pack, or git-upload-archive) of the service + git wants to invoke. + +'%G' (as argument):: + This argument will not be passed to 'program'. Instead, it + will cause helper to start by sending git:// service request to + remote side with service field set to approiate value and + repository field set to . Default is not to send + such request. ++ +This is useful if remote side is git:// server accessed over +some tunnel. + +'%V' (as argument):: + This argument will not be passed to 'program'. Instead it sets + the vhost field in git:// service request. Default is not to + send vhost in such request (if sent). + +ENVIRONMENT VARIABLES: +---------------------- + +GIT_TRANSLOOP_DEBUG:: + If set, prints debugging information about various reads/writes. + +ENVIRONMENT VARIABLES PASSED TO COMMAND: +---------------------------------------- + +GIT_EXT_SERVICE:: + Set to long name (git-upload-pack, etc...) of service helper needs + to invoke. + +GIT_EXT_SERVICE_NOPREFIX:: + Set to long name (upload-pack, etc...) of service helper needs + to invoke. + + +EXAMPLES: +--------- +This remote helper is transparently used by git when +you use commands such as "git fetch ", "git clone ", +, "git push " or "git remote add nick ", where +begins with `ext::`. Examples: + +"ext::ssh -i /home/foo/.ssh/somekey user@host.example %S 'foo/repo'":: + Like host.example:foo/repo, but use /home/foo/.ssh/somekey as + keypair and user as user on remote side. This avoids needing to + edit .ssh/config. + +"ext::socat -t3600 - ABSTRACT-CONNECT:/git-server %G/somerepo":: + Represents repository with path /somerepo accessable over + git protocol at abstract namespace address /git-server. + +"ext::git-server-alias foo %G/repo":: + Represents a repository with path /repo accessed using the + helper program "git-server-alias foo". The path to the + repository and type of request are not passed on the command + line but as part of the protocol stream, as usual with git:// + protocol. + +"ext::git-server-alias foo %G/repo %Vfoo":: + Represents a repository with path /repo accessed using the + helper program "git-server-alias foo". The hostname for the + remote server passed in the protocol stream will be "foo" + (this allows multiple virtual git servers to share a + link-level address). + +"ext::git-server-alias foo %G/repo% with% spaces %Vfoo":: + Represents a repository with path '/repo with spaces' accessed + using the helper program "git-server-alias foo". The hostname for + the remote server passed in the protocol stream will be "foo" + (this allows multiple virtual git servers to share a + link-level address). + +"ext::git-ssl foo.example /bar":: + Represents a repository accessed using the helper program + "git-ssl foo.example /bar". The type of request can be + determined by the helper using environment variables (see + above). + +Documentation +-------------- +Documentation by Ilari Liusvaara, Jonathan Nieder and the git list + + +GIT +--- +Part of the linkgit:git[1] suite diff --git a/Makefile b/Makefile index 17a12dd054..d8ada7892c 100644 --- a/Makefile +++ b/Makefile @@ -723,6 +723,7 @@ BUILTIN_OBJS += builtin/read-tree.o BUILTIN_OBJS += builtin/receive-pack.o BUILTIN_OBJS += builtin/reflog.o BUILTIN_OBJS += builtin/remote.o +BUILTIN_OBJS += builtin/remote-ext.o BUILTIN_OBJS += builtin/remote-fd.o BUILTIN_OBJS += builtin/replace.o BUILTIN_OBJS += builtin/rerere.o diff --git a/builtin.h b/builtin.h index b5da4adc65..c5bfabd01c 100644 --- a/builtin.h +++ b/builtin.h @@ -107,6 +107,7 @@ extern int cmd_read_tree(int argc, const char **argv, const char *prefix); extern int cmd_receive_pack(int argc, const char **argv, const char *prefix); extern int cmd_reflog(int argc, const char **argv, const char *prefix); extern int cmd_remote(int argc, const char **argv, const char *prefix); +extern int cmd_remote_ext(int argc, const char **argv, const char *prefix); extern int cmd_remote_fd(int argc, const char **argv, const char *prefix); extern int cmd_config(int argc, const char **argv, const char *prefix); extern int cmd_rerere(int argc, const char **argv, const char *prefix); diff --git a/builtin/remote-ext.c b/builtin/remote-ext.c new file mode 100644 index 0000000000..1d3f1cf3cc --- /dev/null +++ b/builtin/remote-ext.c @@ -0,0 +1,248 @@ +#include "git-compat-util.h" +#include "transport.h" +#include "run-command.h" + +/* + * URL syntax: + * 'command [arg1 [arg2 [...]]]' Invoke command with given arguments. + * Special characters: + * '% ': Literal space in argument. + * '%%': Literal percent sign. + * '%S': Name of service (git-upload-pack/git-upload-archive/ + * git-receive-pack. + * '%s': Same as \s, but with possible git- prefix stripped. + * '%G': Only allowed as first 'character' of argument. Do not pass this + * Argument to command, instead send this as name of repository + * in in-line git://-style request (also activates sending this + * style of request). + * '%V': Only allowed as first 'character' of argument. Used in + * conjunction with '%G': Do not pass this argument to command, + * instead send this as vhost in git://-style request (note: does + * not activate sending git:// style request). + */ + +static char *git_req; +static char *git_req_vhost; + +static char *strip_escapes(const char *str, const char *service, + const char **next) +{ + size_t rpos = 0; + int escape = 0; + char special = 0; + size_t pslen = 0; + size_t pSlen = 0; + size_t psoff = 0; + struct strbuf ret = STRBUF_INIT; + + /* Calculate prefix length for \s and lengths for \s and \S */ + if (!strncmp(service, "git-", 4)) + psoff = 4; + pSlen = strlen(service); + pslen = pSlen - psoff; + + /* Pass the service to command. */ + setenv("GIT_EXT_SERVICE", service, 1); + setenv("GIT_EXT_SERVICE_NOPREFIX", service + psoff, 1); + + /* Scan the length of argument. */ + while (str[rpos] && (escape || str[rpos] != ' ')) { + if (escape) { + switch (str[rpos]) { + case ' ': + case '%': + case 's': + case 'S': + break; + case 'G': + case 'V': + special = str[rpos]; + if (rpos == 1) + break; + /* Fall-through to error. */ + default: + die("Bad remote-ext placeholder '%%%c'.", + str[rpos]); + } + escape = 0; + } else + escape = (str[rpos] == '%'); + rpos++; + } + if (escape && !str[rpos]) + die("remote-ext command has incomplete placeholder"); + *next = str + rpos; + if (**next == ' ') + ++*next; /* Skip over space */ + + /* + * Do the actual placeholder substitution. The string will be short + * enough not to overflow integers. + */ + rpos = special ? 2 : 0; /* Skip first 2 bytes in specials. */ + escape = 0; + while (str[rpos] && (escape || str[rpos] != ' ')) { + if (escape) { + switch (str[rpos]) { + case ' ': + case '%': + strbuf_addch(&ret, str[rpos]); + break; + case 's': + strbuf_addstr(&ret, service + psoff); + break; + case 'S': + strbuf_addstr(&ret, service); + break; + } + escape = 0; + } else + switch (str[rpos]) { + case '%': + escape = 1; + break; + default: + strbuf_addch(&ret, str[rpos]); + break; + } + rpos++; + } + switch (special) { + case 'G': + git_req = strbuf_detach(&ret, NULL); + return NULL; + case 'V': + git_req_vhost = strbuf_detach(&ret, NULL); + return NULL; + default: + return strbuf_detach(&ret, NULL); + } +} + +/* Should be enough... */ +#define MAXARGUMENTS 256 + +static const char **parse_argv(const char *arg, const char *service) +{ + int arguments = 0; + int i; + const char **ret; + char *temparray[MAXARGUMENTS + 1]; + + while (*arg) { + char *expanded; + if (arguments == MAXARGUMENTS) + die("remote-ext command has too many arguments"); + expanded = strip_escapes(arg, service, &arg); + if (expanded) + temparray[arguments++] = expanded; + } + + ret = xmalloc((arguments + 1) * sizeof(char *)); + for (i = 0; i < arguments; i++) + ret[i] = temparray[i]; + ret[arguments] = NULL; + return (const char **)ret; +} + +static void send_git_request(int stdin_fd, const char *serv, const char *repo, + const char *vhost) +{ + size_t bufferspace; + size_t wpos = 0; + char *buffer; + + /* + * Request needs 12 bytes extra if there is vhost (xxxx \0host=\0) and + * 6 bytes extra (xxxx \0) if there is no vhost. + */ + if (vhost) + bufferspace = strlen(serv) + strlen(repo) + strlen(vhost) + 12; + else + bufferspace = strlen(serv) + strlen(repo) + 6; + + if (bufferspace > 0xFFFF) + die("Request too large to send"); + buffer = xmalloc(bufferspace); + + /* Make the packet. */ + wpos = sprintf(buffer, "%04x%s %s%c", (unsigned)bufferspace, + serv, repo, 0); + + /* Add vhost if any. */ + if (vhost) + sprintf(buffer + wpos, "host=%s%c", vhost, 0); + + /* Send the request */ + if (write_in_full(stdin_fd, buffer, bufferspace) < 0) + die_errno("Failed to send request"); + + free(buffer); +} + +static int run_child(const char *arg, const char *service) +{ + int r; + struct child_process child; + + memset(&child, 0, sizeof(child)); + child.in = -1; + child.out = -1; + child.err = 0; + child.argv = parse_argv(arg, service); + + if (start_command(&child) < 0) + die("Can't run specified command"); + + if (git_req) + send_git_request(child.in, service, git_req, git_req_vhost); + + r = bidirectional_transfer_loop(child.out, child.in); + if (!r) + r = finish_command(&child); + else + finish_command(&child); + return r; +} + +#define MAXCOMMAND 4096 + +static int command_loop(const char *child) +{ + char buffer[MAXCOMMAND]; + + while (1) { + size_t length; + if (!fgets(buffer, MAXCOMMAND - 1, stdin)) { + if (ferror(stdin)) + die("Comammand input error"); + exit(0); + } + /* Strip end of line characters. */ + length = strlen(buffer); + while (isspace((unsigned char)buffer[length - 1])) + buffer[--length] = 0; + + if (!strcmp(buffer, "capabilities")) { + printf("*connect\n\n"); + fflush(stdout); + } else if (!strncmp(buffer, "connect ", 8)) { + printf("\n"); + fflush(stdout); + return run_child(child, buffer + 8); + } else { + fprintf(stderr, "Bad command"); + return 1; + } + } +} + +int cmd_remote_ext(int argc, const char **argv, const char *prefix) +{ + if (argc < 3) { + fprintf(stderr, "Error: URL missing"); + exit(1); + } + + return command_loop(argv[2]); +} diff --git a/git.c b/git.c index b7b96b0dad..e95a1baea2 100644 --- a/git.c +++ b/git.c @@ -374,6 +374,7 @@ static void handle_internal_command(int argc, const char **argv) { "receive-pack", cmd_receive_pack }, { "reflog", cmd_reflog, RUN_SETUP }, { "remote", cmd_remote, RUN_SETUP }, + { "remote-ext", cmd_remote_ext }, { "remote-fd", cmd_remote_fd }, { "replace", cmd_replace, RUN_SETUP }, { "repo-config", cmd_config, RUN_SETUP_GENTLY },