liminix/pkgs/preinit/parseopts.c
Raito Bezarius 3c33c0eaf4 fix(preinit): scan multiple times the cmdline and rename altroot in rootalt
The way the parsing works is examining one character at a time.

First, if we had `rootfstype=... root=...`, the parsing would jump and
ignore `root=...`, which sucks.

To fix this, we scan multiple times a copy of the cmdline.

Now, we have a new problem: `root=... altroot=...` lead to opts.device
being equal to the altroot as we are looking one char at a time, so we
will arrive at a moment looking at `root=...` for `altroot=...`.

To avoid this, we rename `altroot` in `rootalt`, cheap, I know.

Signed-off-by: Raito Bezarius <masterancpp@gmail.com>
2024-08-26 20:08:44 +02:00

179 lines
6.3 KiB
C

#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include "opts.h"
static int begins_with(char * str, char * prefix)
{
while(*prefix) {
if(*str == '\0') return 0;
if(*str != *prefix) return 0;
str++;
prefix++;
}
return 1;
}
char * pr_u32(int32_t input) {
static char buf[9];
const char *digits = "0123456789abcdef";
int i=0;
buf[i] = digits[(input & 0xf0000000) >> 28];
buf[i+1] = digits[(input & 0x0f000000) >> 24];
if(buf[i] != '0' || buf[i+1] != '0') i+=2;
buf[i] = digits[(input & 0x00f00000) >> 20];
buf[i+1] = digits[(input & 0x000f0000) >> 16];
if(buf[i] != '0' || buf[i+1] != '0') i+=2;
buf[i] = digits[(input & 0x0000f000) >> 12];
buf[i+1] = digits[(input & 0x00000f00) >> 8];
if(buf[i] != '0' || buf[i+1] != '0') i+=2;
buf[i] = digits[(input & 0x000000f0) >> 4];
buf[i+1] = digits[(input & 0x0000000f)];
i+=2;
buf[i] ='\0';
if(write(2, buf, i))
return buf;
else
return NULL;
}
static char *eat_word(char *p)
{
while(*p && (*p != ' ')) p++;
if(*p) {
*p = '\0';
p++;
};
return p;
}
static char * eat_param(char *p, char *param_name, char **out)
{
if(begins_with(p, param_name)) {
*out = p + strlen(param_name);
p = eat_word(p);
};
return p;
}
#define SCAN_CMDLINE(cmdline, identifier, field) do { \
for (char* p = strdup(cmdline); *p; p++) { \
p = eat_param(p, identifier, &(opts->field)); \
} \
} while(0)
void parseopts(char * cmdline, struct root_opts *opts) {
SCAN_CMDLINE(cmdline, "root=", device);
SCAN_CMDLINE(cmdline, "rootfstype=", fstype);
SCAN_CMDLINE(cmdline, "rootflags=", mount_opts);
SCAN_CMDLINE(cmdline, "rootalt=", altdevice);
}
#ifdef TESTS
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
// cc -DTESTS -o parseopts parseopts.c && ./parseopts
#define die(fmt, ...) do { printf(fmt, __VA_ARGS__); exit(1); } while(0)
#define S(x) #x
#define expect_equal(actual, expected) \
if(!actual || strcmp(actual, expected)) die("%d: expected \"%s\", got \"%s\"", __LINE__, expected, actual);
#define expect_null(actual) \
if (actual) die("%d: expected null, got \"%s\"", __LINE__, actual);
int main()
{
struct root_opts opts = {
.device = "/dev/hda1",
.fstype = "xiafs",
.altdevice = NULL,
.mount_opts = NULL
};
char *buf;
// finds root= rootfstype= rootflags= options
buf = strdup("liminix console=ttyS0,115200 panic=10 oops=panic init=/bin/init loglevel=8 root=/dev/ubi0_4 rootfstype=ubifs rootflags=subvol=1 fw_devlink=off mtdparts=phram0:18M(rootfs) phram.phram=phram0,0x40400000,18874368,65536 root=/dev/mtdblock0 foo");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.device, "/dev/mtdblock0");
expect_equal(opts.fstype, "ubifs");
expect_equal(opts.mount_opts, "subvol=1");
// finds rootalt= options
buf = strdup("liminix console=ttyS0,115200 panic=10 oops=panic init=/bin/init loglevel=8 root=/dev/ubi0_4 rootfstype=ubifs rootflags=subvol=1 fw_devlink=off mtdparts=phram0:18M(rootfs) phram.phram=phram0,0x40400000,18874368,65536 root=/dev/mtdblock0 rootalt=/dev/mtdblock6 foo");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.device, "/dev/mtdblock0");
expect_equal(opts.altdevice, "/dev/mtdblock6");
expect_equal(opts.fstype, "ubifs");
expect_equal(opts.mount_opts, "subvol=1");
// Ensure that `altdevice` is NULL.
buf = strdup("liminix console=ttyS0,115200 panic=10 oops=panic init=/bin/init loglevel=8 fw_devlink=off rootfstype=ubifs mtdparts=phram0:19791872(rootfs) phram.phram=phram0,33554432,19791872,65536 rootfstype=jffs2 root=/dev/mtdblock0");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.device, "/dev/mtdblock0");
expect_null(opts.altdevice);
expect_equal(opts.fstype, "jffs2");
expect_null(opts.mount_opts);
// in case of duplicates, chooses the latter
// also: works if the option is end of string
buf = strdup("liminix console=ttyS0,115200 panic=10 oops=panic init=/bin/init loglevel=8 root=/dev/ubi0_4 rootfstype=ubifs fw_devlink=off mtdparts=phram0:18M(rootfs) phram.phram=phram0,0x40400000,18874368,65536 root=/dev/mtdblock0");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.device, "/dev/mtdblock0");
expect_equal(opts.fstype, "ubifs");
// options may appear in either order
buf = strdup("liminix fw_devlink=off root=/dev/hda1 rootfstype=ubifs foo");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.device, "/dev/hda1");
expect_equal(opts.fstype, "ubifs");
// works when rootflags is the last option
buf = strdup("liminix fw_devlink=off root=/dev/hda1 rootfstype=ubifs rootflags=subvol=@");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.device, "/dev/hda1");
expect_equal(opts.fstype, "ubifs");
expect_equal(opts.mount_opts, "subvol=@");
buf = strdup("liminix rootfstype=ubifs fw_devlink=off root=/dev/hda1 foo");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
expect_equal(opts.fstype, "ubifs");
expect_equal(opts.device, "/dev/hda1");
// provides NULL for missing options
buf = strdup("liminix rufustype=ubifs fw_devlink=off foot=/dev/hda1");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
if(opts.fstype) die("expected null rootfstype, got \"%s\"", opts.fstype);
if(opts.device) die("expected null root, got \"%s\"", opts.device);
if(opts.mount_opts) die("expected null mount_opts, got \"%s\"", opts.mount_opts);
if(opts.altdevice) die("expected null altdevice, got \"%s\"", opts.altdevice);
// provides empty strings for empty options
buf = strdup("liminix rootfstype= fw_devlink=off root= rootalt= /dev/hda1");
memset(&opts, '\0', sizeof opts); parseopts(buf, &opts);
if(strlen(opts.fstype)) die("expected empty rootfstype, got \"%s\"", opts.fstype);
if(strlen(opts.device)) die("expected empty root, got \"%s\"", opts.device);
if(strlen(opts.altdevice)) die("expected empty rootalt, got \"%s\"", opts.altdevice);
expect_equal("01", pr_u32(1));
expect_equal("ab", pr_u32(0xab));
expect_equal("0abc", pr_u32(0xabc));
expect_equal("aabc", pr_u32(0xaabc));
expect_equal("deadcafe", pr_u32(0xdeadcafe));
}
#endif