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Final (I think) version of xargs. Throw away all that tedious string

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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 2000-09-25 20:23:21 +00:00
parent bf73909f23
commit e081eae7a4
2 changed files with 124 additions and 188 deletions
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152
findutils/xargs.c
View File

@ -28,68 +28,19 @@
#include <errno.h> #include <errno.h>
#include <getopt.h> #include <getopt.h>
#include <ctype.h> #include <ctype.h>
#include <sys/types.h>
/* get_sh_safe_line_from_file() - This function reads an entire line from a text file #include <sys/wait.h>
* up to a newline. It returns a malloc'ed char * which must be stored and
* free'ed by the caller. */
extern char *get_sh_safe_line_from_file(FILE *file)
{
static const int GROWBY = 80; /* how large we will grow strings by */
char ch, last_ch = 0;
char tmp[]=" ";
int idx = 0;
char *linebuf = NULL;
int linebufsz = 0;
while (1) {
ch = fgetc(file);
if (ch == EOF)
break;
/* grow the line buffer as necessary */
while (idx > linebufsz-4)
linebuf = xrealloc(linebuf, linebufsz += GROWBY);
/* Remove any extra spaces */
if (last_ch == ' ' && ch == ' ')
continue;
/* Replace any tabs with spaces */
if (ch == '\t')
ch=' ';
/* Escape any characters that are treated specially by /bin/sh */
*tmp=ch;
if (strpbrk(tmp, "\\~`!$^&*()=|{}[];\"'<>?#") != NULL && last_ch!='\\') {
linebuf[idx++] = '\\';
}
linebuf[idx++] = ch;
last_ch=ch;
if (ch == '\n')
break;
}
if (idx == 0 && last_ch!=0)
linebuf[idx++]=' ';
if (idx == 0)
return NULL;
linebuf[idx] = 0;
return linebuf;
}
int xargs_main(int argc, char **argv) int xargs_main(int argc, char **argv)
{ {
char *in_from_stdin = NULL; char *in_from_stdin = NULL;
char *args_from_cmdline = NULL; char *args = NULL;
char *cmd_to_be_executed = NULL; char *cmd_to_be_executed = NULL;
char traceflag = 0; char traceflag = 0;
int len_args_from_cmdline, len_cmd_to_be_executed, len, opt; int len_args=10, len_cmd_to_be_executed, opt;
pid_t pid;
int wpid, status;
/* Note that we do not use getopt here, since /* Note that we do not use getopt here, since
* we only want to interpret initial options, * we only want to interpret initial options,
@ -106,46 +57,41 @@ int xargs_main(int argc, char **argv)
} }
} }
/* Store the command and arguments to be executed (from the command line) */ /* Store the command to be executed (taken from the command line) */
if (argc == 0) { if (argc == 0) {
len_args_from_cmdline = 6; len_cmd_to_be_executed=6;
args_from_cmdline = xmalloc(len_args_from_cmdline); cmd_to_be_executed = xmalloc(len_cmd_to_be_executed);
strcat(args_from_cmdline, "echo "); strcat(cmd_to_be_executed, "echo");
} else { } else {
opt=strlen(*argv); opt=strlen(*argv);
len_args_from_cmdline = (opt > 10)? opt : 10; len_cmd_to_be_executed = (opt > 10)? opt : 10;
args_from_cmdline = xcalloc(len_args_from_cmdline, sizeof(char));
while (argc-- > 0) {
if (strlen(*argv) + strlen(args_from_cmdline) >
len_args_from_cmdline) {
len_args_from_cmdline += strlen(*argv);
args_from_cmdline =
xrealloc(args_from_cmdline,
len_args_from_cmdline+1);
}
strcat(args_from_cmdline, *argv);
strcat(args_from_cmdline, " ");
++argv;
}
}
/* Set up some space for the command to be executed to be held in */
len_cmd_to_be_executed=10;
cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char)); cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
strcpy(cmd_to_be_executed, args_from_cmdline); strcat(cmd_to_be_executed, *argv);
}
/* Now, read in one line at a time from stdin, and run command+args on it */
in_from_stdin = get_sh_safe_line_from_file(stdin); /* Now, read in one line at a time from stdin, and stroe this to be used later
* as an argument to the command we just stored */
in_from_stdin = get_line_from_file(stdin);
for (;in_from_stdin!=NULL;) { for (;in_from_stdin!=NULL;) {
char *tmp; char *tmp;
opt = strlen(in_from_stdin); opt = strlen(in_from_stdin);
len = opt + len_args_from_cmdline; len_args += opt + 3;
len_cmd_to_be_executed+=len+3; args=xrealloc(args, len_args);
cmd_to_be_executed=xrealloc(cmd_to_be_executed, len_cmd_to_be_executed);
/* Strip out the final \n */ /* Strip out the final \n */
in_from_stdin[opt-1]=' '; in_from_stdin[opt-1]=' ';
/* Replace any tabs with spaces */
while( (tmp = strchr(in_from_stdin, '\t')) != NULL )
*tmp=' ';
/* Strip out any extra intra-word spaces */
while( (tmp = strstr(in_from_stdin, " ")) != NULL ) {
opt = strlen(in_from_stdin);
memmove(tmp, tmp+1, opt-(tmp-in_from_stdin));
}
/* trim trailing whitespace */ /* trim trailing whitespace */
opt = strlen(in_from_stdin) - 1; opt = strlen(in_from_stdin) - 1;
while (isspace(in_from_stdin[opt])) while (isspace(in_from_stdin[opt]))
@ -157,26 +103,49 @@ int xargs_main(int argc, char **argv)
while(isspace(*tmp)) while(isspace(*tmp))
tmp++; tmp++;
strcat(cmd_to_be_executed, tmp); strcat(args, tmp);
strcat(cmd_to_be_executed, " "); strcat(args, " ");
free(in_from_stdin); free(in_from_stdin);
in_from_stdin = get_sh_safe_line_from_file(stdin); in_from_stdin = get_line_from_file(stdin);
} }
if (traceflag==1) if (traceflag==1) {
fputs(cmd_to_be_executed, stderr); fputs(cmd_to_be_executed, stderr);
fputs(args, stderr);
}
if ((system(cmd_to_be_executed) != 0) && (errno != 0)) if ((pid = fork()) == 0) {
fatalError("%s", strerror(errno)); char *cmd[255];
int i=1;
//printf("argv[0]='%s'\n", cmd_to_be_executed);
cmd[0] = cmd_to_be_executed;
while (--argc && ++argv && *argv ) {
//printf("argv[%d]='%s'\n", i, *argv);
cmd[i++]=*argv;
}
//printf("argv[%d]='%s'\n", i, args);
cmd[i++] = args;
cmd[i] = NULL;
execvp(cmd_to_be_executed, cmd);
/* What? Still here? Exit with an error */
fatalError("%s: %s\n", cmd_to_be_executed, strerror(errno));
}
/* Wait for a child process to exit */
wpid = wait(&status);
#ifdef BB_FEATURE_CLEAN_UP #ifdef BB_FEATURE_CLEAN_UP
free(args_from_cmdline); free(args);
free(cmd_to_be_executed); free(cmd_to_be_executed);
#endif #endif
return 0; if (wpid > 0)
return (WEXITSTATUS(status));
else
return EXIT_FAILURE;
} }
/* /*
Local Variables: Local Variables:
@ -185,4 +154,3 @@ c-basic-offset: 4
tab-width: 4 tab-width: 4
End: End:
*/ */

152
xargs.c
View File

@ -28,68 +28,19 @@
#include <errno.h> #include <errno.h>
#include <getopt.h> #include <getopt.h>
#include <ctype.h> #include <ctype.h>
#include <sys/types.h>
/* get_sh_safe_line_from_file() - This function reads an entire line from a text file #include <sys/wait.h>
* up to a newline. It returns a malloc'ed char * which must be stored and
* free'ed by the caller. */
extern char *get_sh_safe_line_from_file(FILE *file)
{
static const int GROWBY = 80; /* how large we will grow strings by */
char ch, last_ch = 0;
char tmp[]=" ";
int idx = 0;
char *linebuf = NULL;
int linebufsz = 0;
while (1) {
ch = fgetc(file);
if (ch == EOF)
break;
/* grow the line buffer as necessary */
while (idx > linebufsz-4)
linebuf = xrealloc(linebuf, linebufsz += GROWBY);
/* Remove any extra spaces */
if (last_ch == ' ' && ch == ' ')
continue;
/* Replace any tabs with spaces */
if (ch == '\t')
ch=' ';
/* Escape any characters that are treated specially by /bin/sh */
*tmp=ch;
if (strpbrk(tmp, "\\~`!$^&*()=|{}[];\"'<>?#") != NULL && last_ch!='\\') {
linebuf[idx++] = '\\';
}
linebuf[idx++] = ch;
last_ch=ch;
if (ch == '\n')
break;
}
if (idx == 0 && last_ch!=0)
linebuf[idx++]=' ';
if (idx == 0)
return NULL;
linebuf[idx] = 0;
return linebuf;
}
int xargs_main(int argc, char **argv) int xargs_main(int argc, char **argv)
{ {
char *in_from_stdin = NULL; char *in_from_stdin = NULL;
char *args_from_cmdline = NULL; char *args = NULL;
char *cmd_to_be_executed = NULL; char *cmd_to_be_executed = NULL;
char traceflag = 0; char traceflag = 0;
int len_args_from_cmdline, len_cmd_to_be_executed, len, opt; int len_args=10, len_cmd_to_be_executed, opt;
pid_t pid;
int wpid, status;
/* Note that we do not use getopt here, since /* Note that we do not use getopt here, since
* we only want to interpret initial options, * we only want to interpret initial options,
@ -106,46 +57,41 @@ int xargs_main(int argc, char **argv)
} }
} }
/* Store the command and arguments to be executed (from the command line) */ /* Store the command to be executed (taken from the command line) */
if (argc == 0) { if (argc == 0) {
len_args_from_cmdline = 6; len_cmd_to_be_executed=6;
args_from_cmdline = xmalloc(len_args_from_cmdline); cmd_to_be_executed = xmalloc(len_cmd_to_be_executed);
strcat(args_from_cmdline, "echo "); strcat(cmd_to_be_executed, "echo");
} else { } else {
opt=strlen(*argv); opt=strlen(*argv);
len_args_from_cmdline = (opt > 10)? opt : 10; len_cmd_to_be_executed = (opt > 10)? opt : 10;
args_from_cmdline = xcalloc(len_args_from_cmdline, sizeof(char));
while (argc-- > 0) {
if (strlen(*argv) + strlen(args_from_cmdline) >
len_args_from_cmdline) {
len_args_from_cmdline += strlen(*argv);
args_from_cmdline =
xrealloc(args_from_cmdline,
len_args_from_cmdline+1);
}
strcat(args_from_cmdline, *argv);
strcat(args_from_cmdline, " ");
++argv;
}
}
/* Set up some space for the command to be executed to be held in */
len_cmd_to_be_executed=10;
cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char)); cmd_to_be_executed = xcalloc(len_cmd_to_be_executed, sizeof(char));
strcpy(cmd_to_be_executed, args_from_cmdline); strcat(cmd_to_be_executed, *argv);
}
/* Now, read in one line at a time from stdin, and run command+args on it */
in_from_stdin = get_sh_safe_line_from_file(stdin); /* Now, read in one line at a time from stdin, and stroe this to be used later
* as an argument to the command we just stored */
in_from_stdin = get_line_from_file(stdin);
for (;in_from_stdin!=NULL;) { for (;in_from_stdin!=NULL;) {
char *tmp; char *tmp;
opt = strlen(in_from_stdin); opt = strlen(in_from_stdin);
len = opt + len_args_from_cmdline; len_args += opt + 3;
len_cmd_to_be_executed+=len+3; args=xrealloc(args, len_args);
cmd_to_be_executed=xrealloc(cmd_to_be_executed, len_cmd_to_be_executed);
/* Strip out the final \n */ /* Strip out the final \n */
in_from_stdin[opt-1]=' '; in_from_stdin[opt-1]=' ';
/* Replace any tabs with spaces */
while( (tmp = strchr(in_from_stdin, '\t')) != NULL )
*tmp=' ';
/* Strip out any extra intra-word spaces */
while( (tmp = strstr(in_from_stdin, " ")) != NULL ) {
opt = strlen(in_from_stdin);
memmove(tmp, tmp+1, opt-(tmp-in_from_stdin));
}
/* trim trailing whitespace */ /* trim trailing whitespace */
opt = strlen(in_from_stdin) - 1; opt = strlen(in_from_stdin) - 1;
while (isspace(in_from_stdin[opt])) while (isspace(in_from_stdin[opt]))
@ -157,26 +103,49 @@ int xargs_main(int argc, char **argv)
while(isspace(*tmp)) while(isspace(*tmp))
tmp++; tmp++;
strcat(cmd_to_be_executed, tmp); strcat(args, tmp);
strcat(cmd_to_be_executed, " "); strcat(args, " ");
free(in_from_stdin); free(in_from_stdin);
in_from_stdin = get_sh_safe_line_from_file(stdin); in_from_stdin = get_line_from_file(stdin);
} }
if (traceflag==1) if (traceflag==1) {
fputs(cmd_to_be_executed, stderr); fputs(cmd_to_be_executed, stderr);
fputs(args, stderr);
}
if ((system(cmd_to_be_executed) != 0) && (errno != 0)) if ((pid = fork()) == 0) {
fatalError("%s", strerror(errno)); char *cmd[255];
int i=1;
//printf("argv[0]='%s'\n", cmd_to_be_executed);
cmd[0] = cmd_to_be_executed;
while (--argc && ++argv && *argv ) {
//printf("argv[%d]='%s'\n", i, *argv);
cmd[i++]=*argv;
}
//printf("argv[%d]='%s'\n", i, args);
cmd[i++] = args;
cmd[i] = NULL;
execvp(cmd_to_be_executed, cmd);
/* What? Still here? Exit with an error */
fatalError("%s: %s\n", cmd_to_be_executed, strerror(errno));
}
/* Wait for a child process to exit */
wpid = wait(&status);
#ifdef BB_FEATURE_CLEAN_UP #ifdef BB_FEATURE_CLEAN_UP
free(args_from_cmdline); free(args);
free(cmd_to_be_executed); free(cmd_to_be_executed);
#endif #endif
return 0; if (wpid > 0)
return (WEXITSTATUS(status));
else
return EXIT_FAILURE;
} }
/* /*
Local Variables: Local Variables:
@ -185,4 +154,3 @@ c-basic-offset: 4
tab-width: 4 tab-width: 4
End: End:
*/ */