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Add reuseable abstraction over fork/exec/dup2 (#211)

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N-R-K 2022-02-20 15:54:29 +00:00 committed by GitHub
parent 3cf4fc5e81
commit ad95012be9
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 113 additions and 45 deletions
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69
main.c
View file

@ -240,29 +240,22 @@ void close_info(void)
void open_info(void)
{
int pfd[2];
spawn_t pfd;
char w[12], h[12];
char *argv[5];
if (info.f.err || info.fd >= 0 || win.bar.h == 0)
return;
win.bar.l.buf[0] = '\0';
if (pipe(pfd) < 0)
return;
if ((info.pid = fork()) == 0) {
close(pfd[0]);
dup2(pfd[1], 1);
snprintf(w, sizeof(w), "%d", img.w);
snprintf(h, sizeof(h), "%d", img.h);
execl(info.f.cmd, info.f.cmd, files[fileidx].name, w, h, NULL);
error(EXIT_FAILURE, errno, "exec: %s", info.f.cmd);
}
close(pfd[1]);
if (info.pid < 0) {
close(pfd[0]);
} else {
fcntl(pfd[0], F_SETFL, O_NONBLOCK);
info.fd = pfd[0];
snprintf(w, sizeof(w), "%d", img.w);
snprintf(h, sizeof(h), "%d", img.h);
construct_argv(argv, ARRLEN(argv), info.f.cmd, files[fileidx].name, w, h, NULL);
pfd = spawn(info.f.cmd, argv, X_READ);
if (pfd.readfd >= 0) {
fcntl(pfd.readfd, F_SETFL, O_NONBLOCK);
info.fd = pfd.readfd;
info.i = info.lastsep = 0;
info.pid = pfd.pid;
}
}
@ -510,15 +503,16 @@ void handle_key_handler(bool init)
static bool run_key_handler(const char *key, unsigned int mask)
{
pid_t pid;
FILE *pfs;
bool marked = mode == MODE_THUMB && markcnt > 0;
bool changed = false;
int f, i, pfd[2];
int f, i;
int fcnt = marked ? markcnt : 1;
char kstr[32];
struct stat *oldst, st;
XEvent dump;
char *argv[3];
spawn_t pfd;
if (keyhandler.f.err) {
if (!keyhandler.warned) {
@ -530,41 +524,27 @@ static bool run_key_handler(const char *key, unsigned int mask)
if (key == NULL)
return false;
if (pipe(pfd) < 0) {
error(0, errno, "pipe");
return false;
}
if ((pfs = fdopen(pfd[1], "w")) == NULL) {
error(0, errno, "open pipe");
close(pfd[0]), close(pfd[1]);
return false;
}
oldst = emalloc(fcnt * sizeof(*oldst));
close_info();
strncpy(win.bar.l.buf, "Running key handler...", win.bar.l.size);
win_draw(&win);
win_set_cursor(&win, CURSOR_WATCH);
setenv("NSXIV_USING_NULL", options->using_null ? "1" : "0", 1);
snprintf(kstr, sizeof(kstr), "%s%s%s%s",
mask & ControlMask ? "C-" : "",
mask & Mod1Mask ? "M-" : "",
mask & ShiftMask ? "S-" : "", key);
setenv("NSXIV_USING_NULL", options->using_null ? "1" : "0", 1);
if ((pid = fork()) == 0) {
close(pfd[1]);
dup2(pfd[0], 0);
execl(keyhandler.f.cmd, keyhandler.f.cmd, kstr, NULL);
error(EXIT_FAILURE, errno, "exec: %s", keyhandler.f.cmd);
}
close(pfd[0]);
if (pid < 0) {
error(0, errno, "fork");
fclose(pfs);
goto end;
construct_argv(argv, ARRLEN(argv), keyhandler.f.cmd, kstr, NULL);
pfd = spawn(keyhandler.f.cmd, argv, X_WRITE);
if (pfd.writefd < 0)
return false;
if ((pfs = fdopen(pfd.writefd, "w")) == NULL) {
close(pfd.writefd);
error(0, errno, "open pipe");
return false;
}
oldst = emalloc(fcnt * sizeof(*oldst));
for (f = i = 0; f < fcnt; i++) {
if ((marked && (files[i].flags & FF_MARK)) || (!marked && i == fileidx)) {
stat(files[i].path, &oldst[f]);
@ -573,7 +553,7 @@ static bool run_key_handler(const char *key, unsigned int mask)
}
}
fclose(pfs);
while (waitpid(pid, NULL, 0) == -1 && errno == EINTR);
while (waitpid(pfd.pid, NULL, 0) == -1 && errno == EINTR);
for (f = i = 0; f < fcnt; i++) {
if ((marked && (files[i].flags & FF_MARK)) || (!marked && i == fileidx)) {
@ -592,7 +572,6 @@ static bool run_key_handler(const char *key, unsigned int mask)
/* drop user input events that occurred while running the key handler */
while (XCheckIfEvent(win.env.dpy, &dump, is_input_ev, NULL));
end:
if (mode == MODE_IMAGE) {
if (changed) {
img_close(&img, true);

13
nsxiv.h
View file

@ -342,6 +342,17 @@ typedef struct {
int stlen;
} r_dir_t;
typedef struct {
int readfd;
int writefd;
pid_t pid;
} spawn_t;
enum {
X_READ = (1 << 0),
X_WRITE = (1 << 1)
};
extern const char *progname;
void* emalloc(size_t);
@ -353,6 +364,8 @@ int r_opendir(r_dir_t*, const char*, bool);
int r_closedir(r_dir_t*);
char* r_readdir(r_dir_t*, bool);
int r_mkdir(char*);
void construct_argv(char**, unsigned int, ...);
spawn_t spawn(const char*, char *const [], unsigned int);
/* window.c */

76
util.c
View file

@ -211,3 +211,79 @@ int r_mkdir(char *path)
}
return 0;
}
void construct_argv(char **argv, unsigned int len, ...)
{
unsigned int i;
va_list args;
va_start(args, len);
for (i = 0; i < len; ++i)
argv[i] = va_arg(args, char *);
va_end(args);
if (argv[len-1] != NULL)
error(EXIT_FAILURE, 0, "argv not NULL terminated");
}
spawn_t spawn(const char *cmd, char *const argv[], unsigned int flags)
{
pid_t pid;
spawn_t status = { -1, -1, -1 };
int pfd_read[2] = { -1, -1 };
int pfd_write[2] = { -1, -1 };
const bool r = flags & X_READ;
const bool w = flags & X_WRITE;
if (cmd == NULL || argv == NULL || flags == 0)
return status;
if (r && pipe(pfd_read) < 0) {
error(0, errno, "pipe: %s", cmd);
return status;
}
if (w && pipe(pfd_write) < 0) {
if (r) {
close(pfd_read[0]);
close(pfd_read[1]);
}
error(0, errno, "pipe: %s", cmd);
return status;
}
if ((pid = fork()) == 0) {
bool err = (r && dup2(pfd_read[1], 1) < 0) || (w && dup2(pfd_write[0], 0) < 0);
if (r) {
close(pfd_read[0]);
close(pfd_read[1]);
}
if (w) {
close(pfd_write[0]);
close(pfd_write[1]);
}
if (err)
error(EXIT_FAILURE, errno, "dup2: %s", cmd);
execv(cmd, argv);
error(EXIT_FAILURE, errno, "exec: %s", cmd);
}
if (r)
close(pfd_read[1]);
if (w)
close(pfd_write[0]);
if (pid < 0) {
if (r)
close(pfd_read[0]);
if (w)
close(pfd_write[1]);
error(0, errno, "fork: %s", cmd);
return status;
}
status.pid = pid;
status.readfd = pfd_read[0];
status.writefd = pfd_write[1];
return status;
}