spawn(): improve performance and simplify API
posix_spawn() is designed especially for this purpose, and thus it's
much more lightweight and efficient than manually fork/dup/exec-ing.
on my system, it improves the performance of spawn() by about 10x. given
that we make frequent calls to potentially multiple scripts, the
increased efficiency will add up overtime.
using posix_spawn() also simplifies the logic quite a bit, despite the
very verbose function names. however it does make cleanup a bit more
complicated.
this patch uses the linux kernel style cleanup strategy [0] (which I'm
personally not a huge fan of, but it fits this situation quite nicely)
with a "stack-like" unwinding via `goto`-s.
additionally simplify the spawn() API by taking in {read,write}fd
pointers and returning the pid instead of using some custom struct.
this coincidently also fixes #299
[0]: https://www.kernel.org/doc/html/v4.10/process/coding-style.html?highlight=goto#centralized-exiting-of-functions
This commit is contained in:
NRK
parent
76c2b81b60
commit
49d11f0d1f
34
main.c
34
main.c
@ -277,9 +277,9 @@ static bool check_timeouts(int *t)
|
||||
static size_t get_win_title(char *buf, size_t len)
|
||||
{
|
||||
char *argv[8];
|
||||
spawn_t pfd;
|
||||
char w[12] = "", h[12] = "", z[12] = "", fidx[12], fcnt[12];
|
||||
ssize_t n = -1;
|
||||
int readfd;
|
||||
|
||||
if (wintitle.f.err || buf == NULL || len == 0)
|
||||
return 0;
|
||||
@ -293,11 +293,10 @@ static size_t get_win_title(char *buf, size_t len)
|
||||
snprintf(fcnt, ARRLEN(fcnt), "%d", filecnt);
|
||||
construct_argv(argv, ARRLEN(argv), wintitle.f.cmd, files[fileidx].path,
|
||||
fidx, fcnt, w, h, z, NULL);
|
||||
pfd = spawn(wintitle.f.cmd, argv, X_READ);
|
||||
if (pfd.readfd >= 0) {
|
||||
if ((n = read(pfd.readfd, buf, len-1)) > 0)
|
||||
if (spawn(&readfd, NULL, argv) > 0) {
|
||||
if ((n = read(readfd, buf, len-1)) > 0)
|
||||
buf[n] = '\0';
|
||||
close(pfd.readfd);
|
||||
close(readfd);
|
||||
}
|
||||
|
||||
return MAX(0, n);
|
||||
@ -314,9 +313,7 @@ void close_info(void)
|
||||
|
||||
void open_info(void)
|
||||
{
|
||||
spawn_t pfd;
|
||||
char w[12] = "", h[12] = "";
|
||||
char *argv[6];
|
||||
char *argv[6], w[12] = "", h[12] = "";
|
||||
char *cmd = mode == MODE_IMAGE ? info.f.cmd : info.ft.cmd;
|
||||
bool ferr = mode == MODE_IMAGE ? info.f.err : info.ft.err;
|
||||
|
||||
@ -329,12 +326,8 @@ void open_info(void)
|
||||
}
|
||||
construct_argv(argv, ARRLEN(argv), cmd, files[fileidx].name, w, h,
|
||||
files[fileidx].path, NULL);
|
||||
pfd = spawn(cmd, argv, X_READ);
|
||||
if (pfd.readfd >= 0) {
|
||||
fcntl(pfd.readfd, F_SETFL, O_NONBLOCK);
|
||||
info.fd = pfd.readfd;
|
||||
info.pid = pfd.pid;
|
||||
}
|
||||
if ((info.pid = spawn(&info.fd, NULL, argv)) > 0)
|
||||
fcntl(info.fd, F_SETFL, O_NONBLOCK);
|
||||
}
|
||||
|
||||
static void read_info(void)
|
||||
@ -579,13 +572,13 @@ static bool run_key_handler(const char *key, unsigned int mask)
|
||||
FILE *pfs;
|
||||
bool marked = mode == MODE_THUMB && markcnt > 0;
|
||||
bool changed = false;
|
||||
int f, i;
|
||||
pid_t pid;
|
||||
int writefd, 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) {
|
||||
@ -608,12 +601,11 @@ static bool run_key_handler(const char *key, unsigned int mask)
|
||||
mask & Mod1Mask ? "M-" : "",
|
||||
mask & ShiftMask ? "S-" : "", key);
|
||||
construct_argv(argv, ARRLEN(argv), keyhandler.f.cmd, kstr, NULL);
|
||||
pfd = spawn(keyhandler.f.cmd, argv, X_WRITE);
|
||||
if (pfd.writefd < 0)
|
||||
if ((pid = spawn(NULL, &writefd, argv)) < 0)
|
||||
return false;
|
||||
if ((pfs = fdopen(pfd.writefd, "w")) == NULL) {
|
||||
if ((pfs = fdopen(writefd, "w")) == NULL) {
|
||||
error(0, errno, "open pipe");
|
||||
close(pfd.writefd);
|
||||
close(writefd);
|
||||
return false;
|
||||
}
|
||||
|
||||
@ -626,7 +618,7 @@ static bool run_key_handler(const char *key, unsigned int mask)
|
||||
}
|
||||
}
|
||||
fclose(pfs);
|
||||
while (waitpid(pfd.pid, NULL, 0) == -1 && errno == EINTR);
|
||||
while (waitpid(pid, NULL, 0) == -1 && errno == EINTR);
|
||||
|
||||
for (f = i = 0; f < fcnt; i++) {
|
||||
if ((marked && (files[i].flags & FF_MARK)) || (!marked && i == fileidx)) {
|
||||
|
||||
13
nsxiv.h
13
nsxiv.h
@ -326,17 +326,6 @@ 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);
|
||||
@ -349,7 +338,7 @@ 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);
|
||||
pid_t spawn(int*, int*, char *const []);
|
||||
|
||||
|
||||
/* window.c */
|
||||
|
||||
111
util.c
111
util.c
@ -21,6 +21,7 @@
|
||||
|
||||
#include <assert.h>
|
||||
#include <errno.h>
|
||||
#include <spawn.h>
|
||||
#include <stdarg.h>
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
@ -28,6 +29,7 @@
|
||||
#include <sys/stat.h>
|
||||
#include <unistd.h>
|
||||
|
||||
extern char **environ;
|
||||
const char *progname = "nsxiv";
|
||||
|
||||
void* emalloc(size_t size)
|
||||
@ -228,60 +230,65 @@ void construct_argv(char **argv, unsigned int len, ...)
|
||||
error(EXIT_FAILURE, 0, "argv not NULL terminated");
|
||||
}
|
||||
|
||||
spawn_t spawn(const char *cmd, char *const argv[], unsigned int flags)
|
||||
static int mkspawn_pipe(posix_spawn_file_actions_t *fa, const char *cmd, int *pfd, int dupidx)
|
||||
{
|
||||
pid_t pid;
|
||||
spawn_t status = { -1, -1, -1 };
|
||||
int pfd_read[2] = { -1, -1 }, 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) {
|
||||
int err;
|
||||
if (pipe(pfd) < 0) {
|
||||
error(0, errno, "pipe: %s", cmd);
|
||||
return status;
|
||||
return -1;
|
||||
}
|
||||
|
||||
if (w && pipe(pfd_write) < 0) {
|
||||
error(0, errno, "pipe: %s", cmd);
|
||||
if (r) {
|
||||
close(pfd_read[0]);
|
||||
close(pfd_read[1]);
|
||||
}
|
||||
return status;
|
||||
err = posix_spawn_file_actions_adddup2(fa, pfd[dupidx], dupidx);
|
||||
err = err ? err : posix_spawn_file_actions_addclose(fa, pfd[0]);
|
||||
err = err ? err : posix_spawn_file_actions_addclose(fa, pfd[1]);
|
||||
if (err) {
|
||||
error(0, err, "posix_spawn_file_actions: %s", cmd);
|
||||
close(pfd[0]);
|
||||
close(pfd[1]);
|
||||
}
|
||||
|
||||
if ((pid = fork()) == 0) { /* in child */
|
||||
if ((r && dup2(pfd_read[1], 1) < 0) || (w && dup2(pfd_write[0], 0) < 0))
|
||||
error(EXIT_FAILURE, errno, "dup2: %s", cmd);
|
||||
|
||||
if (r) {
|
||||
close(pfd_read[0]);
|
||||
close(pfd_read[1]);
|
||||
}
|
||||
if (w) {
|
||||
close(pfd_write[0]);
|
||||
close(pfd_write[1]);
|
||||
}
|
||||
execv(cmd, argv);
|
||||
error(EXIT_FAILURE, errno, "exec: %s", cmd);
|
||||
} else if (pid < 0) { /* fork failed */
|
||||
error(0, errno, "fork: %s", cmd);
|
||||
if (r)
|
||||
close(pfd_read[0]);
|
||||
if (w)
|
||||
close(pfd_write[1]);
|
||||
} else { /* in parent */
|
||||
status.pid = pid;
|
||||
status.readfd = pfd_read[0];
|
||||
status.writefd = pfd_write[1];
|
||||
}
|
||||
|
||||
if (r)
|
||||
close(pfd_read[1]);
|
||||
if (w)
|
||||
close(pfd_write[0]);
|
||||
return status;
|
||||
return err ? -1 : 0;
|
||||
}
|
||||
|
||||
pid_t spawn(int *readfd, int *writefd, char *const argv[])
|
||||
{
|
||||
pid_t pid = -1;
|
||||
const char *cmd;
|
||||
int err, pfd_read[2], pfd_write[2];
|
||||
posix_spawn_file_actions_t fa;
|
||||
|
||||
assert(argv != NULL && argv[0] != NULL);
|
||||
cmd = argv[0];
|
||||
|
||||
if ((err = posix_spawn_file_actions_init(&fa)) != 0) {
|
||||
error(0, err, "spawn: %s", cmd);
|
||||
return pid;
|
||||
}
|
||||
|
||||
if (readfd != NULL && mkspawn_pipe(&fa, cmd, pfd_read, 1) < 0)
|
||||
goto err_destroy_fa;
|
||||
if (writefd != NULL && mkspawn_pipe(&fa, cmd, pfd_write, 0) < 0)
|
||||
goto err_close_readfd;
|
||||
|
||||
if ((err = posix_spawn(&pid, cmd, &fa, NULL, argv, environ)) != 0) {
|
||||
error(0, err, "spawn: %s", cmd);
|
||||
} else {
|
||||
if (readfd != NULL)
|
||||
*readfd = pfd_read[0];
|
||||
if (writefd != NULL)
|
||||
*writefd = pfd_write[1];
|
||||
}
|
||||
|
||||
if (writefd != NULL) {
|
||||
close(pfd_write[0]);
|
||||
if (pid < 0)
|
||||
close(pfd_write[1]);
|
||||
}
|
||||
err_close_readfd:
|
||||
if (readfd != NULL) {
|
||||
if (pid < 0)
|
||||
close(pfd_read[0]);
|
||||
close(pfd_read[1]);
|
||||
}
|
||||
err_destroy_fa:
|
||||
posix_spawn_file_actions_destroy(&fa);
|
||||
return pid;
|
||||
}
|
||||
|
||||
Loading…
Reference in New Issue
Block a user