Final (I think) version of xargs. Throw away all that tedious string
scrubbing, and quit using system. Instead, use fork() and exec(), which yields and smaller, simpler, and cleaner design. -Erik
This commit is contained in:
Eric Andersen
parent
bf73909f23
commit
e081eae7a4
@ -28,68 +28,19 @@
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#include <errno.h>
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#include <getopt.h>
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#include <ctype.h>
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/* get_sh_safe_line_from_file() - This function reads an entire line from a text file
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* up to a newline. It returns a malloc'ed char * which must be stored and
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* free'ed by the caller. */
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extern char *get_sh_safe_line_from_file(FILE *file)
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{
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static const int GROWBY = 80; /* how large we will grow strings by */
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char ch, last_ch = 0;
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char tmp[]=" ";
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int idx = 0;
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char *linebuf = NULL;
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int linebufsz = 0;
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while (1) {
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ch = fgetc(file);
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if (ch == EOF)
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break;
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/* grow the line buffer as necessary */
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while (idx > linebufsz-4)
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linebuf = xrealloc(linebuf, linebufsz += GROWBY);
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/* Remove any extra spaces */
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if (last_ch == ' ' && ch == ' ')
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continue;
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/* Replace any tabs with spaces */
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if (ch == '\t')
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ch=' ';
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/* Escape any characters that are treated specially by /bin/sh */
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*tmp=ch;
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if (strpbrk(tmp, "\\~`!$^&*()=|{}[];\"'<>?#") != NULL && last_ch!='\\') {
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linebuf[idx++] = '\\';
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}
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linebuf[idx++] = ch;
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last_ch=ch;
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if (ch == '\n')
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break;
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}
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if (idx == 0 && last_ch!=0)
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linebuf[idx++]=' ';
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if (idx == 0)
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return NULL;
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linebuf[idx] = 0;
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return linebuf;
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}
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#include <sys/types.h>
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#include <sys/wait.h>
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int xargs_main(int argc, char **argv)
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{
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char *in_from_stdin = NULL;
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char *args_from_cmdline = NULL;
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char *args = NULL;
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char *cmd_to_be_executed = NULL;
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char traceflag = 0;
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int len_args_from_cmdline, len_cmd_to_be_executed, len, opt;
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int len_args=10, len_cmd_to_be_executed, opt;
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pid_t pid;
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int wpid, status;
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/* Note that we do not use getopt here, since
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* we only want to interpret initial options,
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@ -102,50 +53,45 @@ int xargs_main(int argc, char **argv)
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break;
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default:
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fatalError(xargs_usage);
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}
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}
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}
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}
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/* Store the command and arguments to be executed (from the command line) */
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/* Store the command to be executed (taken from the command line) */
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if (argc == 0) {
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len_args_from_cmdline = 6;
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args_from_cmdline = xmalloc(len_args_from_cmdline);
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strcat(args_from_cmdline, "echo ");
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len_cmd_to_be_executed=6;
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cmd_to_be_executed = xmalloc(len_cmd_to_be_executed);
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strcat(cmd_to_be_executed, "echo");
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} else {
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opt=strlen(*argv);
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len_args_from_cmdline = (opt > 10)? opt : 10;
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args_from_cmdline = xcalloc(len_args_from_cmdline, sizeof(char));
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while (argc-- > 0) {
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if (strlen(*argv) + strlen(args_from_cmdline) >
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len_args_from_cmdline) {
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len_args_from_cmdline += strlen(*argv);
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args_from_cmdline =
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xrealloc(args_from_cmdline,
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len_args_from_cmdline+1);
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}
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strcat(args_from_cmdline, *argv);
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strcat(args_from_cmdline, " ");
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++argv;
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}
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len_cmd_to_be_executed = (opt > 10)? opt : 10;
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cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
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strcat(cmd_to_be_executed, *argv);
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}
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/* Set up some space for the command to be executed to be held in */
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len_cmd_to_be_executed=10;
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cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
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strcpy(cmd_to_be_executed, args_from_cmdline);
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/* Now, read in one line at a time from stdin, and run command+args on it */
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in_from_stdin = get_sh_safe_line_from_file(stdin);
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/* Now, read in one line at a time from stdin, and stroe this to be used later
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* as an argument to the command we just stored */
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in_from_stdin = get_line_from_file(stdin);
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for (;in_from_stdin!=NULL;) {
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char *tmp;
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opt = strlen(in_from_stdin);
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len = opt + len_args_from_cmdline;
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len_cmd_to_be_executed+=len+3;
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cmd_to_be_executed=xrealloc(cmd_to_be_executed, len_cmd_to_be_executed);
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len_args += opt + 3;
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args=xrealloc(args, len_args);
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/* Strip out the final \n */
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in_from_stdin[opt-1]=' ';
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/* Replace any tabs with spaces */
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while( (tmp = strchr(in_from_stdin, '\t')) != NULL )
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*tmp=' ';
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/* Strip out any extra intra-word spaces */
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while( (tmp = strstr(in_from_stdin, " ")) != NULL ) {
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opt = strlen(in_from_stdin);
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memmove(tmp, tmp+1, opt-(tmp-in_from_stdin));
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}
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/* trim trailing whitespace */
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opt = strlen(in_from_stdin) - 1;
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while (isspace(in_from_stdin[opt]))
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@ -157,26 +103,49 @@ int xargs_main(int argc, char **argv)
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while(isspace(*tmp))
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tmp++;
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strcat(cmd_to_be_executed, tmp);
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strcat(cmd_to_be_executed, " ");
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strcat(args, tmp);
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strcat(args, " ");
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free(in_from_stdin);
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in_from_stdin = get_sh_safe_line_from_file(stdin);
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in_from_stdin = get_line_from_file(stdin);
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}
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if (traceflag==1)
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if (traceflag==1) {
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fputs(cmd_to_be_executed, stderr);
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fputs(args, stderr);
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}
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if ((system(cmd_to_be_executed) != 0) && (errno != 0))
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fatalError("%s", strerror(errno));
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if ((pid = fork()) == 0) {
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char *cmd[255];
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int i=1;
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//printf("argv[0]='%s'\n", cmd_to_be_executed);
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cmd[0] = cmd_to_be_executed;
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while (--argc && ++argv && *argv ) {
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//printf("argv[%d]='%s'\n", i, *argv);
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cmd[i++]=*argv;
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}
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//printf("argv[%d]='%s'\n", i, args);
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cmd[i++] = args;
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cmd[i] = NULL;
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execvp(cmd_to_be_executed, cmd);
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/* What? Still here? Exit with an error */
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fatalError("%s: %s\n", cmd_to_be_executed, strerror(errno));
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}
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/* Wait for a child process to exit */
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wpid = wait(&status);
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#ifdef BB_FEATURE_CLEAN_UP
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free(args_from_cmdline);
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free(args);
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free(cmd_to_be_executed);
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#endif
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return 0;
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if (wpid > 0)
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return (WEXITSTATUS(status));
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else
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return EXIT_FAILURE;
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}
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/*
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Local Variables:
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@ -185,4 +154,3 @@ c-basic-offset: 4
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tab-width: 4
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End:
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*/
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156
xargs.c
156
xargs.c
@ -28,68 +28,19 @@
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#include <errno.h>
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#include <getopt.h>
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#include <ctype.h>
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/* get_sh_safe_line_from_file() - This function reads an entire line from a text file
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* up to a newline. It returns a malloc'ed char * which must be stored and
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* free'ed by the caller. */
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extern char *get_sh_safe_line_from_file(FILE *file)
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{
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static const int GROWBY = 80; /* how large we will grow strings by */
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char ch, last_ch = 0;
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char tmp[]=" ";
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int idx = 0;
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char *linebuf = NULL;
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int linebufsz = 0;
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while (1) {
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ch = fgetc(file);
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if (ch == EOF)
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break;
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/* grow the line buffer as necessary */
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while (idx > linebufsz-4)
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linebuf = xrealloc(linebuf, linebufsz += GROWBY);
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/* Remove any extra spaces */
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if (last_ch == ' ' && ch == ' ')
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continue;
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/* Replace any tabs with spaces */
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if (ch == '\t')
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ch=' ';
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/* Escape any characters that are treated specially by /bin/sh */
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*tmp=ch;
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if (strpbrk(tmp, "\\~`!$^&*()=|{}[];\"'<>?#") != NULL && last_ch!='\\') {
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linebuf[idx++] = '\\';
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}
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linebuf[idx++] = ch;
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last_ch=ch;
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if (ch == '\n')
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break;
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}
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if (idx == 0 && last_ch!=0)
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linebuf[idx++]=' ';
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if (idx == 0)
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return NULL;
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linebuf[idx] = 0;
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return linebuf;
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}
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#include <sys/types.h>
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#include <sys/wait.h>
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int xargs_main(int argc, char **argv)
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{
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char *in_from_stdin = NULL;
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char *args_from_cmdline = NULL;
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char *args = NULL;
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char *cmd_to_be_executed = NULL;
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char traceflag = 0;
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int len_args_from_cmdline, len_cmd_to_be_executed, len, opt;
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int len_args=10, len_cmd_to_be_executed, opt;
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pid_t pid;
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int wpid, status;
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/* Note that we do not use getopt here, since
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* we only want to interpret initial options,
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@ -102,50 +53,45 @@ int xargs_main(int argc, char **argv)
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break;
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default:
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fatalError(xargs_usage);
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}
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}
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}
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}
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/* Store the command and arguments to be executed (from the command line) */
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/* Store the command to be executed (taken from the command line) */
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if (argc == 0) {
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len_args_from_cmdline = 6;
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args_from_cmdline = xmalloc(len_args_from_cmdline);
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strcat(args_from_cmdline, "echo ");
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len_cmd_to_be_executed=6;
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cmd_to_be_executed = xmalloc(len_cmd_to_be_executed);
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strcat(cmd_to_be_executed, "echo");
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} else {
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opt=strlen(*argv);
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len_args_from_cmdline = (opt > 10)? opt : 10;
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args_from_cmdline = xcalloc(len_args_from_cmdline, sizeof(char));
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while (argc-- > 0) {
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if (strlen(*argv) + strlen(args_from_cmdline) >
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len_args_from_cmdline) {
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len_args_from_cmdline += strlen(*argv);
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args_from_cmdline =
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xrealloc(args_from_cmdline,
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len_args_from_cmdline+1);
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}
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strcat(args_from_cmdline, *argv);
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strcat(args_from_cmdline, " ");
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++argv;
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}
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len_cmd_to_be_executed = (opt > 10)? opt : 10;
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cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
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strcat(cmd_to_be_executed, *argv);
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}
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/* Set up some space for the command to be executed to be held in */
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len_cmd_to_be_executed=10;
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cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
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strcpy(cmd_to_be_executed, args_from_cmdline);
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/* Now, read in one line at a time from stdin, and run command+args on it */
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in_from_stdin = get_sh_safe_line_from_file(stdin);
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/* Now, read in one line at a time from stdin, and stroe this to be used later
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* as an argument to the command we just stored */
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in_from_stdin = get_line_from_file(stdin);
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for (;in_from_stdin!=NULL;) {
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char *tmp;
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opt = strlen(in_from_stdin);
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len = opt + len_args_from_cmdline;
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len_cmd_to_be_executed+=len+3;
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cmd_to_be_executed=xrealloc(cmd_to_be_executed, len_cmd_to_be_executed);
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len_args += opt + 3;
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args=xrealloc(args, len_args);
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/* Strip out the final \n */
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in_from_stdin[opt-1]=' ';
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/* Replace any tabs with spaces */
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while( (tmp = strchr(in_from_stdin, '\t')) != NULL )
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*tmp=' ';
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/* Strip out any extra intra-word spaces */
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while( (tmp = strstr(in_from_stdin, " ")) != NULL ) {
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opt = strlen(in_from_stdin);
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memmove(tmp, tmp+1, opt-(tmp-in_from_stdin));
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}
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/* trim trailing whitespace */
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opt = strlen(in_from_stdin) - 1;
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while (isspace(in_from_stdin[opt]))
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@ -157,26 +103,49 @@ int xargs_main(int argc, char **argv)
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while(isspace(*tmp))
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tmp++;
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strcat(cmd_to_be_executed, tmp);
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strcat(cmd_to_be_executed, " ");
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strcat(args, tmp);
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strcat(args, " ");
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free(in_from_stdin);
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in_from_stdin = get_sh_safe_line_from_file(stdin);
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in_from_stdin = get_line_from_file(stdin);
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}
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if (traceflag==1)
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if (traceflag==1) {
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fputs(cmd_to_be_executed, stderr);
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fputs(args, stderr);
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}
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if ((system(cmd_to_be_executed) != 0) && (errno != 0))
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fatalError("%s", strerror(errno));
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if ((pid = fork()) == 0) {
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char *cmd[255];
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int i=1;
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//printf("argv[0]='%s'\n", cmd_to_be_executed);
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cmd[0] = cmd_to_be_executed;
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while (--argc && ++argv && *argv ) {
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//printf("argv[%d]='%s'\n", i, *argv);
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cmd[i++]=*argv;
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}
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//printf("argv[%d]='%s'\n", i, args);
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cmd[i++] = args;
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cmd[i] = NULL;
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execvp(cmd_to_be_executed, cmd);
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/* What? Still here? Exit with an error */
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fatalError("%s: %s\n", cmd_to_be_executed, strerror(errno));
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}
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/* Wait for a child process to exit */
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wpid = wait(&status);
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#ifdef BB_FEATURE_CLEAN_UP
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free(args_from_cmdline);
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free(args);
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free(cmd_to_be_executed);
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#endif
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return 0;
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if (wpid > 0)
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return (WEXITSTATUS(status));
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else
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return EXIT_FAILURE;
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}
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/*
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Local Variables:
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@ -185,4 +154,3 @@ c-basic-offset: 4
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tab-width: 4
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End:
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*/
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