| 1 | /* |
| 2 | * pty.c - pseudo-terminal handling |
| 3 | */ |
| 4 | |
| 5 | #define _XOPEN_SOURCE |
| 6 | #include <features.h> |
| 7 | |
| 8 | #include <stdio.h> |
| 9 | #include <stdlib.h> |
| 10 | #include <string.h> |
| 11 | #include <assert.h> |
| 12 | |
| 13 | #include <unistd.h> |
| 14 | #include <fcntl.h> |
| 15 | #include <termios.h> |
| 16 | #include <sys/ioctl.h> |
| 17 | #include <sys/types.h> |
| 18 | #include <pwd.h> |
| 19 | |
| 20 | #include "pty.h" |
| 21 | #include "malloc.h" |
| 22 | |
| 23 | static char ptyname[FILENAME_MAX]; |
| 24 | int master = -1; |
| 25 | |
| 26 | void pty_preinit(void) |
| 27 | { |
| 28 | /* |
| 29 | * Allocate the pty. |
| 30 | */ |
| 31 | master = open("/dev/ptmx", O_RDWR); |
| 32 | if (master < 0) { |
| 33 | perror("/dev/ptmx: open"); |
| 34 | exit(1); |
| 35 | } |
| 36 | |
| 37 | if (grantpt(master) < 0) { |
| 38 | perror("grantpt"); |
| 39 | exit(1); |
| 40 | } |
| 41 | |
| 42 | if (unlockpt(master) < 0) { |
| 43 | perror("unlockpt"); |
| 44 | exit(1); |
| 45 | } |
| 46 | } |
| 47 | |
| 48 | void pty_resize(int w, int h) |
| 49 | { |
| 50 | struct winsize sz; |
| 51 | |
| 52 | assert(master >= 0); |
| 53 | |
| 54 | sz.ws_row = h; |
| 55 | sz.ws_col = w; |
| 56 | sz.ws_xpixel = sz.ws_ypixel = 0; |
| 57 | ioctl(master, TIOCSWINSZ, &sz); |
| 58 | } |
| 59 | |
| 60 | int run_program_in_pty(const struct shell_data *shdata, |
| 61 | char *directory, char **program_args) |
| 62 | { |
| 63 | int slave, pid; |
| 64 | char *fallback_args[2]; |
| 65 | |
| 66 | assert(master >= 0); |
| 67 | |
| 68 | ptyname[FILENAME_MAX-1] = '\0'; |
| 69 | strncpy(ptyname, ptsname(master), FILENAME_MAX-1); |
| 70 | |
| 71 | #if 0 |
| 72 | { |
| 73 | struct winsize ws; |
| 74 | struct termios ts; |
| 75 | |
| 76 | /* |
| 77 | * FIXME: think up some good defaults here |
| 78 | */ |
| 79 | |
| 80 | if (!ioctl(0, TIOCGWINSZ, &ws)) |
| 81 | ioctl(master, TIOCSWINSZ, &ws); |
| 82 | if (!tcgetattr(0, &ts)) |
| 83 | tcsetattr(master, TCSANOW, &ts); |
| 84 | } |
| 85 | #endif |
| 86 | |
| 87 | slave = open(ptyname, O_RDWR | O_NOCTTY); |
| 88 | if (slave < 0) { |
| 89 | perror("slave pty: open"); |
| 90 | return 1; |
| 91 | } |
| 92 | |
| 93 | /* |
| 94 | * Fork and execute the command. |
| 95 | */ |
| 96 | pid = fork(); |
| 97 | if (pid < 0) { |
| 98 | perror("fork"); |
| 99 | return 1; |
| 100 | } |
| 101 | |
| 102 | if (pid == 0) { |
| 103 | int i, fd; |
| 104 | |
| 105 | /* |
| 106 | * We are the child. |
| 107 | */ |
| 108 | close(master); |
| 109 | |
| 110 | fcntl(slave, F_SETFD, 0); /* don't close on exec */ |
| 111 | dup2(slave, 0); |
| 112 | dup2(slave, 1); |
| 113 | if (slave != 0 && slave != 1) |
| 114 | close(slave); |
| 115 | dup2(1, 2); |
| 116 | setsid(); |
| 117 | setpgrp(); |
| 118 | i = 0; |
| 119 | #ifdef TIOCNOTTY |
| 120 | if ((fd = open("/dev/tty", O_RDWR)) >= 0) { |
| 121 | ioctl(fd, TIOCNOTTY, &i); |
| 122 | close(fd); |
| 123 | } |
| 124 | #endif |
| 125 | /* |
| 126 | * Make the new pty our controlling terminal. On some OSes |
| 127 | * this is done with TIOCSCTTY; Cygwin doesn't have that, so |
| 128 | * instead it's done by simply opening the pty without |
| 129 | * O_NOCTTY. This code is primarily intended for Cygwin, but |
| 130 | * it's useful to have it work in other contexts for testing |
| 131 | * purposes, so I leave the TIOCSCTTY here anyway. |
| 132 | */ |
| 133 | if ((fd = open(ptyname, O_RDWR)) >= 0) { |
| 134 | #ifdef TIOCSCTTY |
| 135 | ioctl(fd, TIOCSCTTY, &i); |
| 136 | #endif |
| 137 | close(fd); |
| 138 | } else { |
| 139 | perror("slave pty: open"); |
| 140 | exit(127); |
| 141 | } |
| 142 | tcsetpgrp(0, getpgrp()); |
| 143 | |
| 144 | for (i = 0; i < shdata->nenvvars; i++) |
| 145 | putenv(shdata->envvars[i]); |
| 146 | if (shdata->termtype) |
| 147 | putenv(shdata->termtype); |
| 148 | |
| 149 | if (directory) |
| 150 | chdir(directory); |
| 151 | |
| 152 | /* |
| 153 | * Use the provided shell program name, if the user gave |
| 154 | * one. Failing that, use $SHELL; failing that, look up |
| 155 | * the user's default shell in the password file; failing |
| 156 | * _that_, revert to the bog-standard /bin/sh. |
| 157 | */ |
| 158 | if (!program_args) { |
| 159 | char *shell; |
| 160 | |
| 161 | shell = getenv("SHELL"); |
| 162 | if (!shell) { |
| 163 | const char *login; |
| 164 | uid_t uid; |
| 165 | struct passwd *pwd; |
| 166 | |
| 167 | /* |
| 168 | * For maximum generality in the face of multiple |
| 169 | * /etc/passwd entries with different login names and |
| 170 | * shells but a shared uid, we start by using |
| 171 | * getpwnam(getlogin()) if it's available - but we |
| 172 | * insist that its uid must match our real one, or we |
| 173 | * give up and fall back to getpwuid(getuid()). |
| 174 | */ |
| 175 | uid = getuid(); |
| 176 | login = getlogin(); |
| 177 | if (login && (pwd = getpwnam(login)) && pwd->pw_uid == uid) |
| 178 | shell = pwd->pw_shell; |
| 179 | else if ((pwd = getpwuid(uid))) |
| 180 | shell = pwd->pw_shell; |
| 181 | } |
| 182 | if (!shell) |
| 183 | shell = "/bin/sh"; |
| 184 | |
| 185 | fallback_args[0] = shell; |
| 186 | fallback_args[1] = NULL; |
| 187 | program_args = fallback_args; |
| 188 | } |
| 189 | |
| 190 | execv(program_args[0], program_args); |
| 191 | |
| 192 | /* |
| 193 | * If we're here, exec has gone badly foom. |
| 194 | */ |
| 195 | perror("exec"); |
| 196 | exit(127); |
| 197 | } |
| 198 | |
| 199 | close(slave); |
| 200 | |
| 201 | return master; |
| 202 | } |