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IO API: use fork+exec
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@jonas
jonas committed Jan 13, 2009
1 parent 5679054 commit a6113cb
Showing 1 changed file with 69 additions and 87 deletions.
156 changes: 69 additions & 87 deletions tig.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,7 @@
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <unistd.h>
#include <time.h>
Expand Down Expand Up @@ -144,7 +145,6 @@ enum format_flags {
FORMAT_NONE /* No replacement should be performed. */
};

static bool format_command(char dst[], const char *src[], enum format_flags flags);
static bool format_argv(const char *dst[], const char *src[], enum format_flags flags);

struct int_map {
Expand Down Expand Up @@ -270,48 +270,6 @@ suffixcmp(const char *str, int slen, const char *suffix)
return suffixlen < len ? strcmp(str + len - suffixlen, suffix) : -1;
}

/* Shell quoting
*
* NOTE: The following is a slightly modified copy of the git project's shell
* quoting routines found in the quote.c file.
*
* Help to copy the thing properly quoted for the shell safety. any single
* quote is replaced with '\'', any exclamation point is replaced with '\!',
* and the whole thing is enclosed in a
*
* E.g.
* original sq_quote result
* name ==> name ==> 'name'
* a b ==> a b ==> 'a b'
* a'b ==> a'\''b ==> 'a'\''b'
* a!b ==> a'\!'b ==> 'a'\!'b'
*/

static size_t
sq_quote(char buf[SIZEOF_STR], size_t bufsize, const char *src)
{
char c;

#define BUFPUT(x) do { if (bufsize < SIZEOF_STR) buf[bufsize++] = (x); } while (0)

BUFPUT('\'');
while ((c = *src++)) {
if (c == '\'' || c == '!') {
BUFPUT('\'');
BUFPUT('\\');
BUFPUT(c);
BUFPUT('\'');
} else {
BUFPUT(c);
}
}
BUFPUT('\'');

if (bufsize < SIZEOF_STR)
buf[bufsize] = 0;

return bufsize;
}

static bool
argv_from_string(const char *argv[SIZEOF_ARG], int *argc, char *cmd)
Expand Down Expand Up @@ -359,7 +317,7 @@ enum io_type {
struct io {
enum io_type type; /* The requested type of pipe. */
const char *dir; /* Directory from which to execute. */
FILE *pid; /* Pipe for reading or writing. */
pid_t pid; /* Pipe for reading or writing. */
int pipe; /* Pipe end for reading or writing. */
int error; /* Error status. */
const char *argv[SIZEOF_ARG]; /* Shell command arguments. */
Expand All @@ -374,7 +332,7 @@ static void
reset_io(struct io *io)
{
io->pipe = -1;
io->pid = NULL;
io->pid = 0;
io->buf = io->bufpos = NULL;
io->bufalloc = io->bufsize = 0;
io->error = 0;
Expand Down Expand Up @@ -405,42 +363,89 @@ io_open(struct io *io, const char *name)
return io->pipe != -1;
}

static bool
kill_io(struct io *io)
{
return kill(io->pid, SIGKILL) != -1;
}

static bool
done_io(struct io *io)
{
free(io->buf);
if (io->type == IO_FD)
pid_t pid = io->pid;

if (io->pipe != -1)
close(io->pipe);
else if (io->type == IO_RD || io->type == IO_WR)
pclose(io->pid);
free(io->buf);
reset_io(io);

while (pid > 0) {
int status;
pid_t waiting = waitpid(pid, &status, 0);

if (waiting < 0) {
if (errno == EINTR)
continue;
report("waitpid failed (%s)", strerror(errno));
return FALSE;
}

return waiting == pid &&
!WIFSIGNALED(status) &&
WIFEXITED(status) &&
!WEXITSTATUS(status);
}

return TRUE;
}

static bool
start_io(struct io *io)
{
char buf[SIZEOF_STR * 2];
size_t bufpos = 0;
int pipefds[2] = { -1, -1 };

if (io->type == IO_FD)
return TRUE;

if (io->dir && *io->dir &&
!string_format_from(buf, &bufpos, "cd %s;", io->dir))
if ((io->type == IO_RD || io->type == IO_WR) &&
pipe(pipefds) < 0)
return FALSE;

if (!format_command(buf + bufpos, io->argv, FORMAT_NONE))
return FALSE;
if ((io->pid = fork())) {
if (pipefds[!(io->type == IO_WR)] != -1)
close(pipefds[!(io->type == IO_WR)]);
if (io->pid != -1) {
io->pipe = pipefds[!!(io->type == IO_WR)];
return TRUE;
}

} else {
if (io->type != IO_FG) {
int devnull = open("/dev/null", O_RDWR);
int readfd = io->type == IO_WR ? pipefds[0] : devnull;
int writefd = io->type == IO_RD ? pipefds[1] : devnull;

dup2(readfd, STDIN_FILENO);
dup2(writefd, STDOUT_FILENO);
dup2(devnull, STDERR_FILENO);

close(devnull);
if (pipefds[0] != -1)
close(pipefds[0]);
if (pipefds[1] != -1)
close(pipefds[1]);
}

if (io->type == IO_FG || io->type == IO_BG)
return system(buf) == 0;
if (io->dir && *io->dir && chdir(io->dir) == -1)
die("Failed to change directory: %s", strerror(errno));

io->pid = popen(buf, io->type == IO_RD ? "r" : "w");
if (!io->pid)
return FALSE;
io->pipe = fileno(io->pid);
return io->pipe != -1;
execvp(io->argv[0], (char *const*) io->argv);
die("Failed to execute program: %s", strerror(errno));
}

if (pipefds[!!(io->type == IO_WR)] != -1)
close(pipefds[!!(io->type == IO_WR)]);
return FALSE;
}

static bool
Expand Down Expand Up @@ -2554,31 +2559,6 @@ format_argv(const char *dst_argv[], const char *src_argv[], enum format_flags fl
return src_argv[argc] == NULL;
}

static bool
format_command(char dst[], const char *src_argv[], enum format_flags flags)
{
const char *dst_argv[SIZEOF_ARG * 2] = { NULL };
int bufsize = 0;
int argc;

if (!format_argv(dst_argv, src_argv, flags)) {
free_argv(dst_argv);
return FALSE;
}

for (argc = 0; dst_argv[argc] && bufsize < SIZEOF_STR; argc++) {
if (bufsize > 0)
dst[bufsize++] = ' ';
bufsize = sq_quote(dst, bufsize, dst_argv[argc]);
}

if (bufsize < SIZEOF_STR)
dst[bufsize] = 0;
free_argv(dst_argv);

return src_argv[argc] == NULL && bufsize < SIZEOF_STR;
}

static void
end_update(struct view *view, bool force)
{
Expand All @@ -2588,6 +2568,8 @@ end_update(struct view *view, bool force)
if (!force)
return;
set_nonblocking_input(FALSE);
if (force)
kill_io(view->pipe);
done_io(view->pipe);
view->pipe = NULL;
}
Expand Down

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