1#include "rsh.h"
2
3#include <string.h>
4#include <sys/types.h>
5#include <sys/socket.h>
6
7#include "cache.h"
8
9#define COMMAND_SIZE 4096
10
11/*
12 * Write a shell-quoted version of a string into a buffer, and
13 * return bytes that ought to be output excluding final null.
14 */
15static int shell_quote(char *buf, int nmax, const char *str)
16{
17 char ch;
18 int nq;
19 int oc = 0;
20
21 while ( (ch = *str++) ) {
22 nq = 0;
23 if ( strchr(" !\"#$%&\'()*;<=>?[\\]^`{|}", ch) )
24 nq = 1;
25
26 if ( nq ) {
27 if ( nmax > 1 ) {
28 *buf++ = '\\';
29 nmax--;
30 }
31 oc++;
32 }
33
34 if ( nmax > 1 ) {
35 *buf++ = ch;
36 nmax--;
37 }
38 oc++;
39 }
40
41 if ( nmax )
42 *buf = '\0';
43
44 return oc;
45}
46
47/*
48 * Append a string to a string buffer, with or without quoting. Return true
49 * if the buffer overflowed.
50 */
51static int add_to_string(char **ptrp, int *sizep, const char *str, int quote)
52{
53 char *p = *ptrp;
54 int size = *sizep;
55 int oc;
56
57 if ( quote ) {
58 oc = shell_quote(p, size, str);
59 } else {
60 oc = strlen(str);
61 memcpy(p, str, (oc >= size) ? size-1 : oc);
62 }
63
64 if ( oc >= size ) {
65 p[size-1] = '\0';
66 *ptrp += size-1;
67 *sizep = 1;
68 return 1; /* Overflow, string unusable */
69 }
70
71 *ptrp += oc;
72 *sizep -= oc;
73 return 0;
74}
75
76int setup_connection(int *fd_in, int *fd_out, const char *remote_prog,
77 char *url, int rmt_argc, char **rmt_argv)
78{
79 char *host;
80 char *path;
81 int sv[2];
82 char command[COMMAND_SIZE];
83 char *posn;
84 int sizen;
85 int of;
86 int i;
87
88 if (!strcmp(url, "-")) {
89 *fd_in = 0;
90 *fd_out = 1;
91 return 0;
92 }
93
94 host = strstr(url, "//");
95 if (host) {
96 host += 2;
97 path = strchr(host, '/');
98 } else {
99 host = url;
100 path = strchr(host, ':');
101 if (path)
102 *(path++) = '\0';
103 }
104 if (!path) {
105 return error("Bad URL: %s", url);
106 }
107 /* $GIT_RSH <host> "env GIR_DIR=<path> <remote_prog> <args...>" */
108 sizen = COMMAND_SIZE;
109 posn = command;
110 of = 0;
111 of |= add_to_string(&posn, &sizen, "env ", 0);
112 of |= add_to_string(&posn, &sizen, GIT_DIR_ENVIRONMENT, 0);
113 of |= add_to_string(&posn, &sizen, "=", 0);
114 of |= add_to_string(&posn, &sizen, path, 1);
115 of |= add_to_string(&posn, &sizen, " ", 0);
116 of |= add_to_string(&posn, &sizen, remote_prog, 1);
117
118 for ( i = 0 ; i < rmt_argc ; i++ ) {
119 of |= add_to_string(&posn, &sizen, " ", 0);
120 of |= add_to_string(&posn, &sizen, rmt_argv[i], 1);
121 }
122
123 of |= add_to_string(&posn, &sizen, " -", 0);
124
125 if ( of )
126 return error("Command line too long");
127
128 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sv))
129 return error("Couldn't create socket");
130
131 if (!fork()) {
132 const char *ssh, *ssh_basename;
133 ssh = getenv("GIT_SSH");
134 if (!ssh) ssh = "ssh";
135 ssh_basename = strrchr(ssh, '/');
136 if (!ssh_basename)
137 ssh_basename = ssh;
138 else
139 ssh_basename++;
140 close(sv[1]);
141 dup2(sv[0], 0);
142 dup2(sv[0], 1);
143 execlp(ssh, ssh_basename, host, command, NULL);
144 }
145 close(sv[0]);
146 *fd_in = sv[1];
147 *fd_out = sv[1];
148 return 0;
149}