build: cleanup self contained executable

Set $PATH and $TERMINFO_DIRS environment variables, use chdir(2) to
simplify extraction logic, improve error handling.

1 files changed, 110 insertions, 81 deletions

diff --git a/vis-single.c b/vis-single.c
index b6296c0..dc6fe9f 100644
--- a/vis-single.c
+++ b/vis-single.c
@@ -1,18 +1,30 @@
-#define _GNU_SOURCE
-
+#include <sys/wait.h>
 #include <ftw.h>
+#include <limits.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <sys/wait.h>
 #include <unistd.h>
 
-#include <archive.h>
 #include <archive_entry.h>
-#include <sys/acl.h>
+#include <archive.h>
+
+#ifndef PATH_MAX
+#define PATH_MAX 4096
+#endif
 
 #include "vis-single-payload.inc"
 
-int copy_data(struct archive *ar, struct archive *aw) {
+#ifndef VIS_TMP
+#define VIS_TMP "/tmp/.vis-single-XXXXXX"
+#endif
+
+#ifndef VIS_TERMINFO
+#define VIS_TERMINFO "/etc/terminfo:/lib/terminfo:/usr/share/terminfo:" \
+	"/usr/lib/terminfo:/usr/local/share/terminfo:/usr/local/lib/terminfo"
+#endif
+
+static int copy_data(struct archive *ar, struct archive *aw) {
 	int r;
 	const void *buff;
 	size_t size;
@@ -36,116 +48,133 @@ int copy_data(struct archive *ar, struct archive *aw) {
 	return ARCHIVE_OK;
 }
 
-int extract(const char *path) {
-	struct archive *a;
+static int extract(void) {
+	struct archive *in = NULL, *out = NULL;
 	struct archive_entry *entry;
-	struct archive *ext;
-	char * abs_path = NULL;
-	const char * term;
-	char * termenv;
 	int r = ARCHIVE_FAILED;
 
-	if ((a = archive_read_new()) == NULL)
+	if (!(in = archive_read_new()))
 		return ARCHIVE_FAILED;
 
-	if ((r = archive_read_support_filter_xz(a)) != ARCHIVE_OK)
-		goto out10;
+	if ((r = archive_read_support_filter_xz(in)) != ARCHIVE_OK)
+		goto err;
 
-	if ((r = archive_read_support_format_tar(a)) != ARCHIVE_OK)
-		goto out10;
+	if ((r = archive_read_support_format_tar(in)) != ARCHIVE_OK)
+		goto err;
 
-	if ((ext = archive_write_disk_new()) == NULL) {
+	if (!(out = archive_write_disk_new())) {
 		r = ARCHIVE_FAILED;
-		goto out10;
+		goto err;
 	}
 
-	if ((r = archive_read_open_memory(a, vis_single_payload, sizeof(vis_single_payload))) != ARCHIVE_OK) {
-		fprintf(stderr, "archive_read_open_memory() failed: %s\n", archive_error_string(a));
-		goto out20;
+	if ((r = archive_read_open_memory(in, vis_single_payload, sizeof(vis_single_payload))) != ARCHIVE_OK) {
+		fprintf(stderr, "archive_read_open_memory() failed: %s\n", archive_error_string(in));
+		goto err;
 	}
 
-	while (archive_read_next_header(a, &entry) == ARCHIVE_OK) {
-		if (asprintf(&abs_path, "%s/%s", path, archive_entry_pathname(entry)) == -1)
-			goto out20;
-
-		archive_entry_set_pathname(entry, abs_path);
-		free(abs_path);
-
-		if ((r = archive_write_header(ext, entry)) != ARCHIVE_OK) {
-			fprintf(stderr, "archive_write_header() failed: %s\n", archive_error_string(ext));
-			goto out20;
+	while (archive_read_next_header(in, &entry) == ARCHIVE_OK) {
+		if ((r = archive_write_header(out, entry)) != ARCHIVE_OK) {
+			fprintf(stderr, "archive_write_header() failed: %s\n", archive_error_string(out));
+			goto err;
 		}
 
-		if ((r = copy_data(a, ext)) != ARCHIVE_OK)
-			goto out20;
+		if ((r = copy_data(in, out)) != ARCHIVE_OK)
+			goto err;
 
-		if ((r = archive_write_finish_entry(ext)) != ARCHIVE_OK) {
-			fprintf(stderr, "archive_write_finish_entry() failed: %s\n", archive_error_string(ext));
-			goto out20;
+		if ((r = archive_write_finish_entry(out)) != ARCHIVE_OK) {
+			fprintf(stderr, "archive_write_finish_entry() failed: %s\n", archive_error_string(out));
+			goto err;
 		 }
 	}
 
-out20:
-	archive_write_close(ext);
-	archive_write_free(ext);
+err:
+	if (out) {
+		archive_write_close(out);
+		archive_write_free(out);
+	}
 
-out10:
-	archive_read_close(a);
-	archive_read_free(a);
+	if (in) {
+		archive_read_close(in);
+		archive_read_free(in);
+	}
 
-	return ARCHIVE_OK;
+	return r;
 }
 
-int unlink_cb(const char *fpath, const struct stat *sb, int typeflag, struct FTW *ftwbuf) {
-	return remove(fpath);
+static int unlink_cb(const char *path, const struct stat *sb, int typeflag, struct FTW *ftwbuf) {
+	return remove(path);
 }
 
 int main(int argc, char **argv) {
-	char tmp_dirname_template[] = "/tmp/.vis-single-XXXXXX";
-	const char *tmp_dirname;
-	char *abs_path = NULL;
-	const char *term;
-	char *termenv = NULL;
-	int child_pid, statval, rc = EXIT_FAILURE;
-
-	if ((tmp_dirname = mkdtemp(tmp_dirname_template)) == NULL) {
-		perror ("mkdtemp: Could not create tmp directory");
-		goto out10;
+	char exe[256], cwd[PATH_MAX], path[PATH_MAX];
+	int rc = EXIT_FAILURE;
+
+	if (!getcwd(cwd, sizeof(cwd))) {
+		perror("getcwd");
+		return rc;
 	}
 
-	if (extract(tmp_dirname) != ARCHIVE_OK)
-		goto out20;
+	char tmp_dirname_template[] = VIS_TMP;
+	const char *tmp_dirname = mkdtemp(tmp_dirname_template);
 
-	if (asprintf(&abs_path, "%s/vis", tmp_dirname) == -1)
-		goto out20;
+	if (!tmp_dirname) {
+		perror("mkdtemp");
+		return rc;
+	}
 
-	child_pid = fork();
-	if (child_pid == -1) {
-		fprintf(stderr, "could not fork!\n");
-		goto out30;
-	} else if (child_pid == 0) {
-		if ((term = getenv("TERM")) == NULL) {
-			puts("TERM is not defined!");
-			goto out30;
-		}
+	char *old_path = getenv("PATH");
+	if (snprintf(path, sizeof(path), "%s%s%s", tmp_dirname,
+	             old_path ? ":" : "", old_path ? old_path : "") < 0) {
+		goto err;
+	}
+
+	if (setenv("PATH", path, 1) == -1 ||
+	    setenv("TERMINFO_DIRS", VIS_TERMINFO, 0) == -1) {
+		perror("setenv");
+		goto err;
+	}
 
-		if (asprintf(&termenv, "TERM=%s", term) == -1)
-			goto out30;
 
-		char *env[] = { termenv,  NULL };
-		execve(abs_path, argv, env);
+	if (chdir(tmp_dirname) == -1) {
+		perror("chdir");
+		goto err;
 	}
 
-	waitpid(child_pid, &statval, WUNTRACED|WCONTINUED);
-	rc = WEXITSTATUS(statval);
+	if (extract() != ARCHIVE_OK)
+		goto err;
+
+	if (chdir(cwd) == -1) {
+		perror("chdir");
+		goto err;
+	}
 
-out30:
-	free(abs_path);
-	free(termenv);
+	if (snprintf(exe, sizeof(exe), "%s/vis", tmp_dirname) < 0)
+		goto err;
 
-out20:
-	nftw(tmp_dirname, unlink_cb, 64, FTW_DEPTH|FTW_PHYS);
+	int child_pid = fork();
+	if (child_pid == -1) {
+		perror("fork");
+		goto err;
+	} else if (child_pid == 0) {
+		execv(exe, argv);
+		perror("execv");
+		return EXIT_FAILURE;
+	}
+
+	for (;;) {
+		int status;
+		int w = waitpid(child_pid, &status, 0);
+		if (w == -1) {
+			perror("waitpid");
+			break;
+		}
+		if (w == child_pid) {
+			rc = WEXITSTATUS(status);
+			break;
+		}
+	}
 
-out10:
+err:
+	nftw(tmp_dirname, unlink_cb, 64, FTW_DEPTH|FTW_PHYS|FTW_MOUNT);
 	return rc;
 }