1
2#include <unistd.h>
3#include <sys/types.h>
4#include <sys/stat.h>
5#include <fcntl.h>
6#include <string.h>
7#include <linux/string.h>
8#include <errno.h>
9#include <sys/wait.h>
10#include "subcmd-util.h"
11#include "run-command.h"
12#include "exec-cmd.h"
13
14#define STRERR_BUFSIZE 128
15
16static inline void close_pair(int fd[2])
17{
18 close(fd[0]);
19 close(fd[1]);
20}
21
22static inline void dup_devnull(int to)
23{
24 int fd = open("/dev/null", O_RDWR);
25 dup2(fd, to);
26 close(fd);
27}
28
29int start_command(struct child_process *cmd)
30{
31 int need_in, need_out, need_err;
32 int fdin[2], fdout[2], fderr[2];
33 char sbuf[STRERR_BUFSIZE];
34
35
36
37
38
39
40 need_in = !cmd->no_stdin && cmd->in < 0;
41 if (need_in) {
42 if (pipe(fdin) < 0) {
43 if (cmd->out > 0)
44 close(cmd->out);
45 return -ERR_RUN_COMMAND_PIPE;
46 }
47 cmd->in = fdin[1];
48 }
49
50 need_out = !cmd->no_stdout
51 && !cmd->stdout_to_stderr
52 && cmd->out < 0;
53 if (need_out) {
54 if (pipe(fdout) < 0) {
55 if (need_in)
56 close_pair(fdin);
57 else if (cmd->in)
58 close(cmd->in);
59 return -ERR_RUN_COMMAND_PIPE;
60 }
61 cmd->out = fdout[0];
62 }
63
64 need_err = !cmd->no_stderr && cmd->err < 0;
65 if (need_err) {
66 if (pipe(fderr) < 0) {
67 if (need_in)
68 close_pair(fdin);
69 else if (cmd->in)
70 close(cmd->in);
71 if (need_out)
72 close_pair(fdout);
73 else if (cmd->out)
74 close(cmd->out);
75 return -ERR_RUN_COMMAND_PIPE;
76 }
77 cmd->err = fderr[0];
78 }
79
80 fflush(NULL);
81 cmd->pid = fork();
82 if (!cmd->pid) {
83 if (cmd->no_stdin)
84 dup_devnull(0);
85 else if (need_in) {
86 dup2(fdin[0], 0);
87 close_pair(fdin);
88 } else if (cmd->in) {
89 dup2(cmd->in, 0);
90 close(cmd->in);
91 }
92
93 if (cmd->no_stderr)
94 dup_devnull(2);
95 else if (need_err) {
96 dup2(fderr[1], 2);
97 close_pair(fderr);
98 }
99
100 if (cmd->no_stdout)
101 dup_devnull(1);
102 else if (cmd->stdout_to_stderr)
103 dup2(2, 1);
104 else if (need_out) {
105 dup2(fdout[1], 1);
106 close_pair(fdout);
107 } else if (cmd->out > 1) {
108 dup2(cmd->out, 1);
109 close(cmd->out);
110 }
111
112 if (cmd->dir && chdir(cmd->dir))
113 die("exec %s: cd to %s failed (%s)", cmd->argv[0],
114 cmd->dir, str_error_r(errno, sbuf, sizeof(sbuf)));
115 if (cmd->env) {
116 for (; *cmd->env; cmd->env++) {
117 if (strchr(*cmd->env, '='))
118 putenv((char*)*cmd->env);
119 else
120 unsetenv(*cmd->env);
121 }
122 }
123 if (cmd->preexec_cb)
124 cmd->preexec_cb();
125 if (cmd->exec_cmd) {
126 execv_cmd(cmd->argv);
127 } else {
128 execvp(cmd->argv[0], (char *const*) cmd->argv);
129 }
130 exit(127);
131 }
132
133 if (cmd->pid < 0) {
134 int err = errno;
135 if (need_in)
136 close_pair(fdin);
137 else if (cmd->in)
138 close(cmd->in);
139 if (need_out)
140 close_pair(fdout);
141 else if (cmd->out)
142 close(cmd->out);
143 if (need_err)
144 close_pair(fderr);
145 return err == ENOENT ?
146 -ERR_RUN_COMMAND_EXEC :
147 -ERR_RUN_COMMAND_FORK;
148 }
149
150 if (need_in)
151 close(fdin[0]);
152 else if (cmd->in)
153 close(cmd->in);
154
155 if (need_out)
156 close(fdout[1]);
157 else if (cmd->out)
158 close(cmd->out);
159
160 if (need_err)
161 close(fderr[1]);
162
163 return 0;
164}
165
166static int wait_or_whine(pid_t pid)
167{
168 char sbuf[STRERR_BUFSIZE];
169
170 for (;;) {
171 int status, code;
172 pid_t waiting = waitpid(pid, &status, 0);
173
174 if (waiting < 0) {
175 if (errno == EINTR)
176 continue;
177 fprintf(stderr, " Error: waitpid failed (%s)",
178 str_error_r(errno, sbuf, sizeof(sbuf)));
179 return -ERR_RUN_COMMAND_WAITPID;
180 }
181 if (waiting != pid)
182 return -ERR_RUN_COMMAND_WAITPID_WRONG_PID;
183 if (WIFSIGNALED(status))
184 return -ERR_RUN_COMMAND_WAITPID_SIGNAL;
185
186 if (!WIFEXITED(status))
187 return -ERR_RUN_COMMAND_WAITPID_NOEXIT;
188 code = WEXITSTATUS(status);
189 switch (code) {
190 case 127:
191 return -ERR_RUN_COMMAND_EXEC;
192 case 0:
193 return 0;
194 default:
195 return -code;
196 }
197 }
198}
199
200int finish_command(struct child_process *cmd)
201{
202 return wait_or_whine(cmd->pid);
203}
204
205int run_command(struct child_process *cmd)
206{
207 int code = start_command(cmd);
208 if (code)
209 return code;
210 return finish_command(cmd);
211}
212
213static void prepare_run_command_v_opt(struct child_process *cmd,
214 const char **argv,
215 int opt)
216{
217 memset(cmd, 0, sizeof(*cmd));
218 cmd->argv = argv;
219 cmd->no_stdin = opt & RUN_COMMAND_NO_STDIN ? 1 : 0;
220 cmd->exec_cmd = opt & RUN_EXEC_CMD ? 1 : 0;
221 cmd->stdout_to_stderr = opt & RUN_COMMAND_STDOUT_TO_STDERR ? 1 : 0;
222}
223
224int run_command_v_opt(const char **argv, int opt)
225{
226 struct child_process cmd;
227 prepare_run_command_v_opt(&cmd, argv, opt);
228 return run_command(&cmd);
229}
230
