1 files changed, 111 insertions, 0 deletions
diff --git a/src/program.c b/src/program.c
new file mode 100644
index 0000000..c396695
--- /dev/null
+++ b/src/program.c
@@ -0,0 +1,111 @@
+#include "program.h"
+#include "buffer.h"
+#include <unistd.h>
+#include <sys/wait.h>
+#include <sys/prctl.h>
+#include <errno.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#define READ_END 0
+#define WRITE_END 1
+
+int program_buffer_write_callback(char *data, int size, void *userdata) {
+    Buffer *buffer = userdata;
+    buffer_append(buffer, data, size);
+    return 0;
+}
+
+int program_exec(const char **args, ProgramOutputCallback output_callback, void *userdata) {
+    /* 1 arguments */
+    if(args[0] == NULL)
+        return -1;
+    
+    int fd[2];
+    if(pipe(fd) == -1) {
+        perror("Failed to open pipe");
+        return -2;
+    }
+
+    pid_t parent_pid = getpid();
+
+    pid_t pid = fork();
+    if(pid == -1) {
+        perror("Failed to fork");
+        return -3;
+    } else if(pid == 0) { /* child */
+        if(prctl(PR_SET_PDEATHSIG, SIGTERM) == -1) {
+            perror("prctl(PR_SET_PDEATHSIG, SIGTERM) failed");
+            exit(127);
+        }
+
+        /* Test if the parent died before the above call to prctl */
+        if(getppid() != parent_pid)
+            exit(127);
+
+        dup2(fd[WRITE_END], STDOUT_FILENO);
+        close(fd[READ_END]);
+        close(fd[WRITE_END]);
+
+        execvp(args[0], (char* const*)args);
+        perror("execvp");
+        exit(127);
+    } else { /* parent */
+        close(fd[WRITE_END]);
+
+        int result = 0;
+        int status;
+
+        char buffer[4097];
+
+        if(output_callback) {
+            for(;;) {
+                ssize_t bytes_read = read(fd[READ_END], buffer, sizeof(buffer) - 1);
+                if(bytes_read == 0) {
+                    break;
+                } else if(bytes_read == -1) {
+                    int err = errno;
+                    fprintf(stderr, "Failed to read from pipe to program %s, error: %s\n", args[0], strerror(err));
+                    result = -err;
+                    goto cleanup;
+                }
+
+                buffer[bytes_read] = '\0';
+                if(output_callback(buffer, bytes_read, userdata) != 0)
+                    break;
+            }
+        }
+
+        if(waitpid(pid, &status, 0) == -1) {
+            perror("waitpid failed");
+            result = -5;
+            goto cleanup;
+        }
+
+        if(!WIFEXITED(status)) {
+            result = -4;
+            goto cleanup;
+        }
+
+        int exit_status = WEXITSTATUS(status);
+        if(exit_status != 0) {
+            fprintf(stderr, "Failed to execute program (");
+            const char **arg = args;
+            while(*arg) {
+                if(arg != args)
+                    fputc(' ', stderr);
+                fprintf(stderr, "'%s'", *arg);
+                ++arg;
+            }
+            fprintf(stderr, "), exit status %d\n", exit_status);
+            result = -exit_status;
+            goto cleanup;
+        }
+
+        cleanup:
+        close(fd[READ_END]);
+        return result;
+    }
+}