File: posix_process.cpp

package info (click to toggle)
diagnostics 0.3.3-12.1
  • links: PTS
  • area: main
  • in suites: bullseye
  • size: 4,148 kB
  • sloc: cpp: 13,603; sh: 10,950; makefile: 225; ansic: 9
file content (157 lines) | stat: -rw-r--r-- 4,742 bytes parent folder | download | duplicates (6)
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
145
146
147
148
149
150
151
152
153
154
155
156
157
/*
 * Copyright (C) 2010 Florian Weimer <fw@deneb.enyo.de>
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <diagnostics/extensions/stacktrace/descriptor.hpp>
#include <diagnostics/extensions/stacktrace/signal.hpp>
#include <diagnostics/extensions/stacktrace/process.hpp>
#include <diagnostics/extensions/stacktrace/raw_process.hpp>

#include <cerrno>
#include <poll.h>
#include <sys/wait.h>
#include <unistd.h>

DIAGNOSTICS_NAMESPACE_BEGIN;
STACKTRACE_NAMESAPCE_BEGIN;

POSIX::ProcessResult::ProcessResult()
: Status(-1), Signal(-1)
{
}

POSIX::ProcessResult::~ProcessResult()
{
}

// Read from OUTPUT and ERROR and store the result in RESULT.
static void
run(pid_t pid,
    POSIX::Descriptor &output, POSIX::Descriptor &error,
    POSIX::ProcessResult &result)
{
  int nfds = 2;
  struct pollfd fds[2];
  fds[0].fd = output.GetRaw();
  fds[0].events = POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI;
  fds[1].fd = error.GetRaw();
  fds[1].events = POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI;

  std::string *strings[2];
  strings[0] = &result.Output;
  strings[1] = &result.Error;

  result.Output.clear();
  result.Error.clear();

  char buf[1024];
  while (nfds > 0) {
    // Always use both descriptors, the kernel will skip them if necessary.
    POSIX::Error::Unless(poll(fds, 2, -1) >= 1);
    for (int i = 0; i < 2; ++i) {
      if (fds[i].revents & POLLNVAL) {
        throw POSIX::Error(EBADF);
      }

      if (fds[i].revents
                 & (POLLIN | POLLRDNORM | POLLRDBAND | POLLPRI)) {
        int ret = read(fds[i].fd, buf, sizeof(buf));
        switch (ret) {
        case 0:
          // EOF, release this descriptor.
          fds[i].events = 0;
          --nfds;
          break;
        case -1:
          if (errno != EAGAIN && errno != EWOULDBLOCK) {
            throw POSIX::Error();
          }
          break;
        default:
          strings[i]->append(buf, ret);
        }
      } else if (fds[i].revents & (POLLERR | POLLHUP )) {
        // Can also be set when POLLIN etc. is set.  In this case, we
        // could safe a poll syscall when the read was smaller than
        // the whole buffer.
        fds[i].events = 0;
        --nfds;
      }
    }
  }

  int status;
  POSIX::Error::Unless(waitpid(pid, &status, 0) >= 0);
  if (WIFEXITED(status)) {
    result.Status = WEXITSTATUS(status);
    result.Signal = -1;
  } else if (WIFSIGNALED(status)) {
    result.Status = -1;
    result.Signal = WTERMSIG(status);
  } else {
    // Cannot actually happen.
    result.Status = -1;
    result.Signal = -1;
  }
}

void
POSIX::Run(const char *program, char *const args[], char *const env[],
                 ProcessResult &result)
{
  Sigset block_chld;
  block_chld.Add(SIGCHLD);
  SaveSigProcMask saved(block_chld);

  POSIX::Pipe output, error;
  output.Read().SetCloseOnExec(true);
  output.Read().SetNonBlocking(true);
  error.Read().SetCloseOnExec(true);
  error.Read().SetNonBlocking(true);

  SpawnFileActions actions;
  actions.AddOpen(0, "/dev/null", O_RDONLY, 0);
  actions.AddDup2(output.Write().GetRaw(), 1);
  actions.AddDup2(error.Write().GetRaw(), 2);

  SpawnAttr attr;
  // Ideally, we would want to restore all signals to their default
  // handlers, but if we specify the full set, the spawn fails in the
  // child (silently!).
  attr.SetSigDefault(Sigset().Add(SIGINT).Add(SIGQUIT));
  attr.SetFlags(POSIX_SPAWN_SETSIGDEF);

  pid_t pid;
  POSIX::Error::Unless
    (posix_spawnp(&pid, program,
                  actions.GetRaw(), attr.GetRaw(),
                  args, env) == 0);
  output.Write().Close();
  error.Write().Close();

  run(pid, output.Read(), error.Read(), result);
}

STACKTRACE_NAMESAPCE_END;
DIAGNOSTICS_NAMESPACE_END;