91 lines
2.6 KiB
C
91 lines
2.6 KiB
C
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// Copyright 2022 Nicholas J. Kain <njkain at gmail dot com>
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// SPDX-License-Identifier: MIT
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#include <sys/types.h>
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#include <stdbool.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include "nk/nstrcpy.h"
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#include "nk/pspawn.h"
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#include "nk/io.h"
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#define MAX_ARGS 256
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#define MAX_ARGBUF 16384
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#define NK_GEN_ARG(STRVAL, STRLEN) do { \
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char *snp = nstrcpyl(argbuf, argbuflen, STRVAL, STRLEN); \
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if (!snp) { \
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static const char errstr[] = "nk_pspawn: constructing argument list failed\n"; \
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safe_write(STDERR_FILENO, errstr, sizeof errstr); \
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_Exit(EXIT_FAILURE); \
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} \
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argv[curv] = argbuf; argv[++curv] = NULL; \
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size_t l = (size_t)(snp - argbuf); \
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argbuf += l; argbuflen -= l; \
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} while (0)
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int nk_pspawn(pid_t *pid, const char *command,
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const posix_spawn_file_actions_t *restrict file_actions,
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const posix_spawnattr_t *restrict attrp,
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const char *args, char * const envp[])
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{
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char *argv[MAX_ARGS];
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char argbuf_s[MAX_ARGBUF];
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char *argbuf = argbuf_s;
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size_t curv = 0;
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size_t argbuflen = sizeof argbuf_s;
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if (!command)
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_Exit(EXIT_SUCCESS);
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// strip the path from the command name and set argv[0]
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const char *p = strrchr(command, '/');
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{
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const char *q = p ? p + 1 : command;
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size_t ql = strlen(q);
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NK_GEN_ARG(q, ql);
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}
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if (args) {
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p = args;
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const char *q = args;
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bool squote = false, dquote = false, atend = false;
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for (;; ++p) {
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switch (*p) {
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default: continue;
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case '\0':
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atend = true;
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goto endarg;
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case ' ':
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if (!squote && !dquote)
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goto endarg;
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continue;
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case '\'':
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if (!dquote)
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squote = !squote;
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continue;
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case '"':
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if (!squote)
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dquote = !dquote;
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continue;
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}
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endarg:
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{
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if (p == q) break;
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// Push an argument.
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if (q > p) {
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static const char errstr[] = "nk_execute: argument length too long\n";
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safe_write(STDERR_FILENO, errstr, sizeof errstr);
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_Exit(EXIT_FAILURE);
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}
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NK_GEN_ARG(q, (size_t)(p - q));
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q = p + 1;
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if (atend || curv >= (MAX_ARGS - 1))
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break;
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}
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}
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}
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return posix_spawn(pid, command, file_actions, attrp, argv, envp);
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}
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