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authorN-R-K <79544946+N-R-K@users.noreply.github.com>2022-02-20 15:54:29 +0000
committerGitHub <noreply@github.com>2022-02-20 15:54:29 +0000
commitad95012be993664e062e7724155c54a482a51315 (patch)
tree519744b4b6ed6b99266505991a0e954d709e9d4d
parent3cf4fc5e816cdda1ae2108987b9558ea6968b9e9 (diff)
Add reuseable abstraction over fork/exec/dup2 (#211)
-rw-r--r--main.c69
-rw-r--r--nsxiv.h13
-rw-r--r--util.c76
3 files changed, 113 insertions, 45 deletions
diff --git a/main.c b/main.c
index ebbbc3a..40f104e 100644
--- a/main.c
+++ b/main.c
@@ -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);
diff --git a/nsxiv.h b/nsxiv.h
index a9d4dad..b6b04fb 100644
--- a/nsxiv.h
+++ b/nsxiv.h
@@ -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 */
diff --git a/util.c b/util.c
index ef0ec43..d580839 100644
--- a/util.c
+++ b/util.c
@@ -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;
+}