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#define _POSIX_C_SOURCE 200809L
#define _DEFAULT_SOURCE 1
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdbool.h>
#include <errno.h>
#include <stdarg.h>
#include <string.h>
#include <sys/wait.h>
static char *g_eofstr = NULL;
static char *g_replstr = NULL;
static size_t g_line_count = -1;
static size_t g_arg_count = -1;
static bool g_prompt = false;
static size_t g_size = -1;
static bool g_trace = false;
static bool g_terminate = false;
static char *g_name = "xargs";
void die(const char *fmt, ...)
{
va_list ap;
va_start(ap, fmt);
fprintf(stderr, "%s: ", g_name);
vfprintf(stderr, fmt, ap);
fputc('\n', stderr);
va_end(ap);
exit(1);
}
void *xmalloc(size_t size)
{
void *ret = malloc(size);
if (ret == NULL)
die(strerror(errno));
return ret;
}
char *xstrdup(const char *src)
{
char *ret = strdup(src);
if (ret == NULL)
die(strerror(errno));
return ret;
}
size_t parse_uint(const char *optarg)
{
unsigned long n;
char *end;
errno = 0;
n = strtoul(optarg, &end, 10);
if (!isdigit(*optarg) || errno != 0 || *end != '\0')
die("invalid number \"%s\"", optarg);
return n;
}
size_t args_len(char **args)
{
size_t len;
for (len = 0; args[len] != NULL; len++);
return len;
}
void args_free(char **args)
{
for (size_t i = 0; args[i] != NULL; i++)
free(args[i]);
free(args);
}
char **args_cpy(char **dst, char **src)
{
size_t i;
for (i = 0; src[i] != NULL; i++)
dst[i] = xstrdup(src[i]);
dst[i] = NULL;
return dst;
}
char **args_dup(char **src)
{
char **ret = xmalloc((args_len(src) + 1) * sizeof(char*));
return args_cpy(ret, src);
}
int main(int argc, char **argv)
{
int option;
while ((option = getopt(argc, argv, "E:I:L:n:ps:tx")) > 0)
{
switch (option)
{
case 'E': g_eofstr = optarg; break;
case 'I': g_replstr = optarg; break;
case 'L': g_line_count = parse_uint(optarg); break;
case 'n': g_arg_count = parse_uint(optarg); break;
case 'p': g_prompt = true; break;
case 's': g_size = parse_uint(optarg); break;
case 't': g_trace = true; break;
case 'x': g_terminate = true; break;
}
}
if (g_line_count == 0)
die("value 0 for -L option should be >= 1");
if (g_arg_count == 0)
die("value 0 for -n option should be >= 1");
if (g_prompt)
g_trace = true;
char *cmd = optind != argc ? argv[optind] : "echo";
char **args_prefix;
if (optind == argc || optind + 1 == argc)
{
args_prefix = xmalloc(2 * sizeof(char*));
args_prefix[0] = cmd;
args_prefix[1] = NULL;
}
else
{
size_t len = argc - optind;
args_prefix = xmalloc((len + 1) * sizeof(char*));
size_t i;
for (i = 0; i < len; i++)
args_prefix[i] = argv[optind + i];
args_prefix[len] = NULL;
}
size_t len;
bool eof = false;
size_t command_count = 0;
while (!eof)
{
char **args = args_dup(args_prefix);
char *line = NULL;
size_t line_size = 0;
size_t count = 0;
while (getline(&line, &line_size, stdin) > 0)
{
// removing newline
char *last = line + strlen(line) - 1;
if (*last == '\n')
*last = '\0';
// trim blank characters
while (isblank(*line))
memmove(line, line + 1, strlen(line));
len = strlen(line);
while (len > 0 && isblank(line[len - 1]))
{
line[len - 1] = '\0';
len--;
}
// skipping blank lines
if (*line == '\0')
continue;
// stopping if eof string encountered
if (g_eofstr != NULL && strcmp(g_eofstr, line) == 0)
{
eof = true;
break;
}
// add line to arguments
len = args_len(args);
char **new_args = xmalloc((len + 2) * sizeof(char*));
args_cpy(new_args, args);
new_args[len] = xstrdup(line);
new_args[len + 2] = NULL;
/* args_free(args); */
args = new_args;
count++;
if ((g_line_count != (size_t)-1 && count >= g_line_count) ||
(g_arg_count != (size_t)-1 && count >= g_arg_count))
break;
}
if (feof(stdin))
eof = true;
if (eof && command_count != 0 && !g_prompt)
break;
command_count++;
pid_t child_pid;
child_pid = fork();
switch (child_pid)
{
case -1:
die(strerror(errno));
break;
case 0:
if (g_trace)
for (size_t i = 0; args[i] != NULL; i++)
{
fputs(args[i], stderr);
if (args[i + 1] != NULL)
fputc(' ', stderr);
}
bool confirmation = true;
if (g_prompt)
{
FILE *tty_file = fopen("/dev/tty", "r");
if (tty_file == NULL)
die("Couldn't open tty file");
fputs(" ?...", stderr);
int c = fgetc(tty_file);
confirmation = c == 'y' || c == 'Y';
}
else if (g_trace)
fputc('\n', stderr);
if (!confirmation)
exit(0);
execvp(cmd, args);
die(strerror(errno));
}
waitpid(child_pid, &child_pid, 0);
if (WEXITSTATUS(child_pid) == 255)
break;
}
return 0;
}
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