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/* Invoke $EDITOR as a filter.
*
* Copyright (c) 2016 Dmitry Bogatov <KAction@gnu.org>
* Copyright (c) 2017 Marc André Tanner <mat@brain-dump.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
static void error(const char *msg, ...) {
va_list ap;
va_start(ap, msg);
vfprintf(stderr, msg, ap);
va_end(ap);
if (errno)
fprintf(stderr, ": %s", strerror(errno));
fprintf(stderr, "\n");
}
int main(int argc, char *argv[])
{
int exit_status = EXIT_FAILURE, tmp_write = -1;
const char *editor = getenv("DVTM_EDITOR");
if (!editor)
editor = getenv("VISUAL");
if (!editor)
editor = getenv("EDITOR");
if (!editor)
editor = "vi";
char tempname[] = "/tmp/dvtm-editor.XXXXXX";
if ((tmp_write = mkstemp(tempname)) == -1) {
error("failed to open temporary file `%s'", tempname);
goto err;
}
/* POSIX does not mandates modes of temporary file. */
if (fchmod(tmp_write, 0600) == -1) {
error("failed to change mode of temporary file `%s'", tempname);
goto err;
}
char buffer[2048];
ssize_t bytes;
while ((bytes = read(STDIN_FILENO, buffer, sizeof(buffer))) > 0) {
do {
ssize_t written = write(tmp_write, buffer, bytes);
if (written == -1) {
error("failed to write data to temporary file `%s'",
tempname);
goto err;
}
bytes -= written;
} while (bytes > 0);
}
if (fsync(tmp_write) == -1) {
error("failed to fsync temporary file `%s'", tempname);
goto err;
}
struct stat stat_before;
if (fstat(tmp_write, &stat_before) == -1) {
error("failed to stat newly created temporary file `%s'", tempname);
goto err;
}
if (close(tmp_write) == -1) {
error("failed to close temporary file `%s'", tempname);
goto err;
}
pid_t pid = fork();
if (pid == -1) {
error("failed to fork editor process");
goto err;
} else if (pid == 0) {
int tty = open("/dev/tty", O_RDWR);
if (tty == -1) {
error("failed to open /dev/tty");
_exit(1);
}
if (dup2(tty, STDIN_FILENO) == -1) {
error("failed to set tty as stdin");
_exit(1);
}
if (dup2(tty, STDOUT_FILENO) == -1) {
error("failed to set tty as stdout");
_exit(1);
}
if (dup2(tty, STDERR_FILENO) == -1) {
error("failed to set tty as stderr");
_exit(1);
}
close(tty);
const char *editor_argv[argc+2];
editor_argv[0] = editor;
for (int i = 1; i < argc; i++)
editor_argv[i] = argv[i];
editor_argv[argc] = tempname;
editor_argv[argc+1] = NULL;
execvp(editor, (char* const*)editor_argv);
error("failed to exec editor process `%s'", editor);
_exit(127);
}
int status;
if (waitpid(pid, &status, 0) == -1) {
error("waitpid failed");
goto err;
}
if (!WIFEXITED(status)) {
error("editor invocation failed");
goto err;
}
if ((status = WEXITSTATUS(status)) != 0) {
error("editor terminated with exit status: %d", status);
goto err;
}
int tmp_read = open(tempname, O_RDONLY);
if (tmp_read == -1) {
error("failed to open for reading of edited temporary file `%s'",
tempname);
goto err;
}
struct stat stat_after;
if (fstat(tmp_read, &stat_after) == -1) {
error("failed to stat edited temporary file `%s'", tempname);
goto err;
}
if (stat_before.st_mtime == stat_after.st_mtime)
goto ok; /* no modifications */
while ((bytes = read(tmp_read, buffer, sizeof(buffer))) > 0) {
do {
ssize_t written = write(STDOUT_FILENO, buffer, bytes);
if (written == -1) {
error("failed to write data to stdout");
goto err;
}
bytes -= written;
} while (bytes > 0);
}
ok:
exit_status = EXIT_SUCCESS;
err:
if (tmp_write != -1)
unlink(tempname);
return exit_status;
}
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