libpakfire: execute: Create fds to read output in parent process

This will be used to log any output of the executed command in the
parent process.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/src/libpakfire/execute.c b/src/libpakfire/execute.c
index 4ce6805ea30447f574ac226ffb022cba922cf982..35a5434a989d0c156a2a09522ae90dfa0b3791a8 100644 (file)
--- a/src/libpakfire/execute.c
+++ b/src/libpakfire/execute.c
@@ -39,6 +39,10 @@ struct pakfire_execute {
        Pakfire pakfire;
        const char** argv;
        char** envp;
+
+       // File descriptors
+       int stdout[2];
+       int stderr[2];
 };
 
 static int pakfire_execute_fork(void* data) {
@@ -79,6 +83,30 @@ static int pakfire_execute_fork(void* data) {
                }
        }
 
+       // Connect standard output and error
+       if (env->stdout[1] && env->stderr[1]) {
+               if (dup2(env->stdout[1], STDOUT_FILENO) < 0) {
+                       ERROR(pakfire, "Could not connect fd %d to stdout: %s\n",
+                               env->stdout[1], strerror(errno));
+
+                       return 1;
+               }
+
+               if (dup2(env->stderr[1], STDERR_FILENO) < 0) {
+                       ERROR(pakfire, "Could not connect fd %d to stderr: %s\n",
+                               env->stderr[1], strerror(errno));
+
+                       return 1;
+               }
+
+               // Close the reading sides of the pipe
+               close(env->stdout[0]);
+               close(env->stderr[0]);
+
+               // Close standard input
+               close(STDIN_FILENO);
+       }
+
        // exec() command
        int r = execve(env->argv[0], (char**)env->argv, env->envp);
        if (r < 0) {
@@ -113,6 +141,23 @@ PAKFIRE_EXPORT int pakfire_execute(Pakfire pakfire, const char* argv[], char* en
        if (!(flags & PAKFIRE_EXECUTE_ENABLE_NETWORK))
                cflags |= CLONE_NEWNET;
 
+       // Make some file descriptors for stdout & stderr
+       if (flags & PAKFIRE_EXECUTE_LOG_OUTPUT) {
+               if (pipe(env.stdout) < 0) {
+                       ERROR(pakfire, "Could not create file descriptors for stdout: %s\n",
+                               strerror(errno));
+
+                       return -errno;
+               }
+
+               if (pipe(env.stderr) < 0) {
+                       ERROR(pakfire, "Could not create file descriptors for stderr: %s\n",
+                               strerror(errno));
+
+                       return -errno;
+               }
+       }
+
        // Fork this process
        pid_t pid = clone(pakfire_execute_fork, stack + sizeof(stack), cflags, &env);
        if (pid < 0) {
@@ -121,21 +166,35 @@ PAKFIRE_EXPORT int pakfire_execute(Pakfire pakfire, const char* argv[], char* en
                return -errno;
        }
 
+       // Close any unused file descriptors
+       if (env.stdout[1])
+               close(env.stdout[1]);
+       if (env.stderr[1])
+               close(env.stderr[1]);
+
        DEBUG(pakfire, "Waiting for PID %d to finish its work\n", pid);
 
        int status;
        waitpid(pid, &status, 0);
 
+       // Set some useful error code
+       int r = -ESRCH;
+
        if (WIFEXITED(status)) {
-               int r = WEXITSTATUS(status);
+               r = WEXITSTATUS(status);
 
                DEBUG(pakfire, "Child process exited with code: %d\n", r);
-               return r;
+       } else {
+               ERROR(pakfire, "Could not determine the exit status of process %d\n", pid);
        }
 
-       ERROR(pakfire, "Could not determine the exit status of process %d\n", pid);
+       // Close any file descriptors
+       if (env.stdout[0])
+               close(env.stdout[0]);
+       if (env.stderr[0])
+               close(env.stderr[0]);
 
-       return -ESRCH;
+       return r;
 }
 
 PAKFIRE_EXPORT int pakfire_execute_command(Pakfire pakfire, const char* command, char* envp[], int flags) {

diff --git a/src/libpakfire/include/pakfire/execute.h b/src/libpakfire/include/pakfire/execute.h
index 18fa0754beeff504afabba7f2a2cc63cb0b9838f..c9cb02c2dbd4f235ffe9d2234cf3b27d1e8d9c92 100644 (file)
--- a/src/libpakfire/include/pakfire/execute.h
+++ b/src/libpakfire/include/pakfire/execute.h
@@ -28,7 +28,8 @@ int pakfire_execute_command(Pakfire pakfire, const char* command, char* envp[],
 
 enum {
        PAKFIRE_EXECUTE_NONE                    = 0,
-       PAKFIRE_EXECUTE_ENABLE_NETWORK  = 1,
+       PAKFIRE_EXECUTE_ENABLE_NETWORK  = (1 << 0),
+       PAKFIRE_EXECUTE_LOG_OUTPUT      = (1 << 1),
 };
 
 #endif /* PAKFIRE_EXECUTE_H */