summary refs log tree commit diff
path: root/src/libnix/exec.cc
blob: 2e092b2e0dd6010d966048fa6258b9e6ebd98ead (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
#include <iostream>

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <unistd.h>
#include <fcntl.h>

#include "exec.hh"
#include "util.hh"
#include "globals.hh"


class AutoDelete
{
    string path;
    bool del;
public:

    AutoDelete(const string & p) : path(p) 
    {
        del = true;
    }

    ~AutoDelete()
    {
        if (del) deletePath(path);
    }

    void cancel()
    {
        del = false;
    }
};


static string pathNullDevice = "/dev/null";


/* Run a program. */
void runProgram(const string & program, 
    const Strings & args, const Environment & env)
{
    /* Create a log file. */
    string logFileName = nixLogDir + "/run.log";
    string logCommand = 
	verbosity >= lvlDebug 
	? "tee -a "  + logFileName + " >&2"
	: "cat >> " + logFileName;
    /* !!! auto-pclose on exit */
    FILE * logFile = popen(logCommand.c_str(), "w"); /* !!! escaping */
    if (!logFile)
        throw SysError(format("creating log file `%1%'") % logFileName);

    /* Create a temporary directory where the build will take
       place. */
    string tmpDir = createTempDir();

    AutoDelete delTmpDir(tmpDir);

    /* Fork a child to build the package. */
    pid_t pid;
    switch (pid = fork()) {
            
    case -1:
        throw SysError("unable to fork");

    case 0: 

        try { /* child */

            if (chdir(tmpDir.c_str()) == -1)
                throw SysError(format("changing into to `%1%'") % tmpDir);

            /* Fill in the arguments. */
            const char * argArr[args.size() + 2];
            const char * * p = argArr;
            string progName = baseNameOf(program);
            *p++ = progName.c_str();
            for (Strings::const_iterator i = args.begin();
                 i != args.end(); i++)
                *p++ = i->c_str();
            *p = 0;

            /* Fill in the environment. */
            Strings envStrs;
            const char * envArr[env.size() + 1];
            p = envArr;
            for (Environment::const_iterator i = env.begin();
                 i != env.end(); i++)
                *p++ = envStrs.insert(envStrs.end(), 
                    i->first + "=" + i->second)->c_str();
            *p = 0;

            /* Dup the log handle into stderr. */
            if (dup2(fileno(logFile), STDERR_FILENO) == -1)
                throw SysError("cannot pipe standard error into log file");
            
            /* Dup stderr to stdin. */
            if (dup2(STDERR_FILENO, STDOUT_FILENO) == -1)
                throw SysError("cannot dup stderr into stdout");

	    /* Reroute stdin to /dev/null. */
	    int fdDevNull = open(pathNullDevice.c_str(), O_RDWR);
	    if (fdDevNull == -1)
		throw SysError(format("cannot open `%1%'") % pathNullDevice);
	    if (dup2(fdDevNull, STDIN_FILENO) == -1)
		throw SysError("cannot dup null device into stdin");

            /* Execute the program.  This should not return. */
            execve(program.c_str(), (char * *) argArr, (char * *) envArr);

            throw SysError(format("unable to execute %1%") % program);
            
        } catch (exception & e) {
            cerr << format("build error: %1%\n") % e.what();
        }
        _exit(1);

    }

    /* parent */

    /* Close the logging pipe.  Note that this should not cause
       the logger to exit until builder exits (because the latter
       has an open file handle to the former). */
    pclose(logFile);
    
    /* Wait for the child to finish. */
    int status;
    if (waitpid(pid, &status, 0) != pid)
        throw Error("unable to wait for child");
    
    if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
	if (keepFailed) {
	    msg(lvlTalkative, 
		format("build failed; keeping build directory `%1%'") % tmpDir);
	    delTmpDir.cancel();
	}
        throw Error("unable to build package");
    }
}