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exec tweaks

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This commit is contained in:
Russ Cox 2009-07-13 09:34:45 -07:00
parent fd8e368101
commit b3bebfce8a
1 changed files with 11 additions and 6 deletions
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17
exec.c
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@ -16,19 +16,21 @@ exec(char *path, char **argv)
struct inode *ip; struct inode *ip;
struct proghdr ph; struct proghdr ph;
mem = 0;
sz = 0;
if((ip = namei(path)) == 0) if((ip = namei(path)) == 0)
return -1; return -1;
ilock(ip); ilock(ip);
// Compute memory size of new process. // Check ELF header
mem = 0;
sz = 0;
// Program segments.
if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf)) if(readi(ip, (char*)&elf, 0, sizeof(elf)) < sizeof(elf))
goto bad; goto bad;
if(elf.magic != ELF_MAGIC) if(elf.magic != ELF_MAGIC)
goto bad; goto bad;
// Compute memory size of new process.
// Program segments.
for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){ for(i=0, off=elf.phoff; i<elf.phnum; i++, off+=sizeof(ph)){
if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph)) if(readi(ip, (char*)&ph, off, sizeof(ph)) != sizeof(ph))
goto bad; goto bad;
@ -44,7 +46,10 @@ exec(char *path, char **argv)
for(argc=0; argv[argc]; argc++) for(argc=0; argv[argc]; argc++)
arglen += strlen(argv[argc]) + 1; arglen += strlen(argv[argc]) + 1;
arglen = (arglen+3) & ~3; arglen = (arglen+3) & ~3;
sz += arglen + 4*(argc+1); sz += arglen;
sz += 4*(argc+1); // argv data
sz += 4; // argv
sz += 4; // argc
// Stack. // Stack.
sz += PAGE; sz += PAGE;